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. 2022 Dec 1;17(12):e0278610. doi: 10.1371/journal.pone.0278610

Risk factors for cerebral complications in patients with pulmonary arteriovenous malformations: A multicenter retrospective cohort study

Young-Ok Na 1,2, Hwa Kyung Park 1,2, Jae-Kyeong Lee 1,2, Bo-Gun Kho 1,2, Tae-Ok Kim 1,2, Hong-Joon Shin 1,2,*, Yong-Soo Kwon 1,2, Yu-Il Kim 1,2, Sung-Chul Lim 1,2, Hyung-Joo Oh 1,2, Cheol-Kyu Park 2,3, In-Jae Oh 2,3, Young-Chul Kim 2,3, Ha-Young Park 2,4
Editor: Alfred Pokmeng See5
PMCID: PMC9714939  PMID: 36454973

Abstract

Objective

Pulmonary arteriovenous malformation (PAVM) is a rare pulmonary disease. Although most patients with PAVMs are asymptomatic, cerebral complications associated with PAVMs are often fatal. This study aimed to evaluate the risk factors for cerebral complications in patients with PAVMs.

Methods

We retrospectively reviewed the medical charts of patients with PAVMs between 2003 and 2021 at two tertiary referral hospitals and one secondary hospital.

Results

Fifty-five patients diagnosed with PAVMs were enrolled in this study. Most patients were female (89.1%), and the median age was 53 years. Thirty patients (54.5%) had incidentally detected PAVMs without symptoms. Twenty-four patients (43.7%) with PAVMs were treated with embolotherapy or surgery. Thirteen patients (23.6%) had cerebral complications. There was no significant difference in the development of cerebral complications according to treatment; however, older age (≥ 65 years) was associated with the development of new cerebral complications in untreated patients with PAVMs (odds ratio, 17.09; 95% confidence interval, 1.16–250.31; P = 0.038).

Conclusion

Older age (≥ 65 years) was a risk factor for the development of cerebral complications in patients with PAVMs; therefore, treatment should be considered in older patients with PAVMs.

Introduction

Pulmonary arteriovenous malformation (PAVM) is a rare pulmonary disease, characterized by abnormal direct vascular communications between pulmonary arteries and veins resulting in right-to-left shunts [1]. The most common cause of PAVMs is hereditary hemorrhagic telangiectasia (HHT), although it varies by region and race [1–5].Most patients with PAVMs are asymptomatic; however, symptoms such as dyspnea, hemoptysis, chest discomfort, and neurological symptoms may accompany PAVMs [4, 6–10].

Serious complications of PAVMs include hypoxia, hemothorax, stroke, and brain abscess [6–8, 10, 11]. Treatments for PAVM, such as embolotherapy, reduce the development of PAVM complications [12]. Cerebral complications are reported in 9% to 41% of patients with PAVM, which can be fatal [6–11]. The risk of cerebral complications is low in younger patients, but high in patients with multiple PAVMs [13, 14]. The risk factor of cerebral complications associated with PAVM is not well known.

This study aimed to evaluate the risk factors associated with cerebral complications in patients with PAVMs.

Patients and methods

Study design and population

We retrospectively reviewed the medical charts of patients with PAVMs between January 2003 and May 2021 at two tertiary referral hospitals and one secondary hospital. We screened patients with PAVMs using diagnostic code, chest computed tomography (CT) findings, or pulmonary angiography findings during the study period. PAVMs were diagnosed by chest CT with enhancement or pulmonary angiography.

Data collection

We investigated the patients’ age, sex, underlying diseases (hypertension and diabetes), mode of PAVM detection (initial symptoms or incidentally), and treatments. We also investigated the types and feeding artery diameters of PAVMs and presence of HHT. The diagnoses of HHT were made according to the Curacao diagnostic criteria for HHT [15] as follows: spontaneous, recurrent nose bleeds; multiple telangiectasis, especially in the lips, oral cavity, fingers, and nose; visceral lesions such as gastrointestinal telangiectasia; hepatic and cerebral arteriovenous malformations; and a first-degree relative with HHT. Definite HHT was classified as patients who fulfilled three or more of the above-mentioned criteria. Probable HHT was classified as patients with two criteria fulfillments. The feeding artery and venous sac diameters were measured [16]. A modified Rankin Scale (mRS) score was used to evaluate the degree of disability or dependence in daily activities in patients with PAVM with cerebral complications [17]. The cerebral complications associated with PAVM were divided into cerebral ischemia, hemorrhage, and abscess. To determine whether there had been any brain complications before PAVM diagnosis, we reviewed the patient’s medical records. A brain CT or MRI was used to diagnose cerebral complications associated with PAVM at the time of initial PAVM diagnosis or after PAVM was detected.

Types of PAVMs

We classified the PAVMs as single and multiple types. Multiple PAVMs were defined as at least two PAVMs observed on imaging findings.

Definition

Patients with incidentally detected PAVM were those whose PAVM was detected during a health screening, preoperative evaluation, or evaluation of other diseases, and presented asymptomatically.

Evaluation of recanalization after embolotherapy

Patients who had a follow-up chest CT scan after embolotherapy were analyzed to evaluate recanalization. An evaluation of recanalization was performed on patients who had a follow-up chest CT scan after embolotherapy [6, 7, 18]. Recanalization was determined by 70% criteria following embolotherapy, which means less than 70% regression of the PAVM sac and draining vein [18].

Ethics statement

The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The protocol which was conducted according to the principle expressed in the Declaration of Helsinki (as revised in 2013). The Institutional Review Board at Chonnam National University Hospital (Gwangju, Republic of Korea) approved the study protocol and permitted the review and publication of our findings, as well as that of information derived from patient records (CNUH 2022–055) requirement for informed consent was waived because of the retrospective nature of the study, and approved by the Ethics Committee. Patient information was fully rendered innominate before the analysis.

Statistical analyses

All data were expressed as medians with interquartile ranges or numbers (percentages). Factors associated with cerebral complications were selected by univariate logistic regression analysis. Subsequent multivariate logistic regression analyses included variables with P values< 0.2 in the univariate analysis using a backward method. We used Kaplan–Meier analysis to evaluate the time without development of cerebral complications. Factors associated with cerebral complications were identified using Cox-regression analysis that included variables with P < 0.2 in the univariate analysis using the backward method. All statistical analyses were performed using SPSS version 25.0 (IBM, Armonk, NY, USA); a P value of <0.05 was considered statistically significant.

Results

A total of 70 individuals were screened, of which 15 were excluded for the following reasons: a CT or angiography did not reveal PAVM (n = 11), or they were diagnosed with pulmonary sequestration (n = 3) or a pulmonary venous anomaly (n = 1). Therefore, a total of 55 patients with PAVM were enrolled in this study.

Patient characteristics

Fifty-five patients diagnosed with PAVMs were enrolled in this study. The median follow-up duration was 20.4 months (interquartile range, 3.3–50.5 months). The baseline characteristics of the study patients are shown in Table 1. Most patients were female (89.1%), and the median age was 53 years. The most common type of PAVMs was the single type (76.4%). Only one patient had HHT. Thirty patients had incidentally detected PAVM via the following: health screening (n = 18), preoperative evaluation (n = 6), or evaluation of other diseases (n = 6). A total of thirteen patients (23.6%) had cerebral complications, including cerebral ischemia (n = 11), cerebral hemorrhage (n = 1), and cerebral abscess (n = 1). Of the 13 patients with cerebral complications, six developed these complications before their PAVM diagnosis, five developed these complications concurrently with their PAVM diagnosis, and two developed these complications after their PAVM diagnosis. Twenty-one (38.2%) patients underwent transcatheter embolization for PAVMs. Of these, two patients were not treated at the time of PAVM diagnosis and underwent embolotherapy after developing cerebral complications. Three patients (5.5%) underwent surgery for PAVMs. Cerebral complications occurred in four patients who did not undergo treatment after a PAVM diagnosis, and two patients had previous cerebral complications. Cerebral complications in all four patients included cerebral ischemia, and one patient showed severe functional impairments, with an mRS score of 5. The other three patients, however, only showed mild impairments with mRS scores of 1–3 (S1 Table). None of the patients who underwent treatment for PAVM developed further cerebral complications during the follow-up period.

Table 1. Baseline characteristics of patients with pulmonary arteriovenous malformations.

Variables n (%)
Total
    Male 6 (10.9)
    Female 49 (89.1)
Age, yrs
    Median 53
    IQR 45–62
Types of PAVMs
    Single 42 (76.4)
    Multiple 13 (23.6)
Location of PAVMs
    Right upper lobe 11 (20.0)
    Right middle lobe 10 (18.2)
    Right lower lobe 14 (25.5)
    Left upper lobe 19 (34.5)
    Left lower lobe 15 (27.3)
Hereditary hemorrhagic telangiectasia 1 (1.8)
Feeding artery diameter, mm
    Median 4.1
    IQR 3.3–4.8
Venous sac diameter, mm
    Median 11.8
    IQR 8.4–17.3
Underlying disease
    Diabetes 3 (5.5)
    Hypertension 11 (20.0)
Causes of detection
    Incidentally 30 (54.5)
    Coughing 7 (12.7)
    Neurologic symptoms 4 (7.3)
    Chest pain 4 (7.3)
    Hemoptysis 3 (5.5)
    Dyspnea 3 (5.5)
    Pneumonia 2 (3.6)
    Others 2 (3.6)
Cerebral complications 13 (23.6)
Cerebral ischemia 11 (84.6)
    Cerebral hemorrhage 1 (7.7)
    Cerebral abscess 1 (7.7)
Treatment
    Observation 31 (56.4)
    Transcatheter embolization 21 (38.2)
    Surgery 3 (5.5)
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IQR, interquartile range; PAVM, pulmonary arteriovenous malformation

A follow-up chest CT scan was performed on 13 of the 21 PAVM patients who underwent embolotherapy, and among them, recanalization was observed in two.

Fig 1 shows the number of patients diagnosed with PAVM in the three hospitals at 5-year intervals since 2003. Each year, the number of newly diagnosed PAVM patients has increased. In particular, the number of patients diagnosed incidentally without symptoms associated with PAVM has increased.

Fig 1. Number of patients diagnosed with pulmonary arteriovenous malformation from 2003 to 2021.

Fig 1

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Risk factors for cerebral complications associated with PAVMs

We evaluated the risk factors for cerebral complications, including cerebral hemorrhage and ischemia, at the time of PAVM diagnosis (Table 2). Multivariate logistic regression analysis showed older age (≥ 65 years) was associated with increased cerebral complications (odds ratio [OR], 23.18; 95% confidence interval [CI], 2.61–205.45; P = 0.005)(Table 2). In contrast, patients with incidentally detected PAVMs showed decreased rates of cerebral complications (OR 0.14; 95% CI, 0.02–0.88; P = 0.037). Furthermore, the incidence of cerebral complications was low in incidentally detected patients.

Table 2. Risk factors associated with cerebral complications in patients with pulmonary arteriovenous malformations (n = 55).

Variables OR 95% CI P value
Univariate analysis
Age ≥ 65 10.85 2.18–53.95 0.004
Male < 0.00 0.00–0.00 0.999
Incidental detection 0.25 0.06–0.97 0.046
Hypertension 3.75 0.91–15.40 0.067
Diabetes 7.45 0.61–90.00 0.114
Feeding artery diameter 1.08 0.76–1.53 0.647
Venous sac diameter 0.98 0.90–1.08 0.804
Types of PAVM 0.96 0.22–4.18 0.957
Location of PAVM
    Right upper lobe 0.26 0.31–2.31 0.230
    Right middle lobe 0.77 0.14–4.19 0.765
    Right lower lobe 1.42 0.35–5.62 0.616
    Left upper lobe 0.80 0.21–3.04 0.743
    Left lower lobe 2.00 0.53–7.51 0.305
Multivariate analysis
Age ≥ 65 23.18 2.61–205.45 0.005
Incidental detection 0.14 0.02–0.88 0.037
Hypertension 7.53 0.86–65.50 0.067
Diabetes <0.00 0.00–0.00 0.999
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OR, odds ratio; CI, confidence interval; PAVM, pulmonary arteriovenous malformation

Fig 2 shows the Kaplan–Meier curve for the development of new cerebral complications in the treated and untreated groups after PAVM diagnosis.

Fig 2. Kaplan–Meier curve illustrating the time without the development of new cerebral complications associated with PAVM treatment.

Fig 2

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The untreated group tended to develop more cerebral complications during the follow-up period; however, there was no significant difference between the two groups (log-rank P = 0.088).

Subgroup analysis of risk factors for new cerebral complications among untreated patients with PAVMs

We investigated the risk factors associated with new cerebral complications in 33 patients who did not receive treatment after their PAVM diagnosis. Multivariate logistic regression analysis showed older age (≥65 years) was associated with increased cerebral complications (OR, 17.09; 95% CI, 1.16–250.31; P = 0.038) (Table 3).

Table 3. Risk factors for new cerebral complications in untreated patients after PAVMs were detected (n = 33).

Variables OR 95% CI P value
Univariate analysis
Age ≥ 65 18.00 1.48–218.95 0.023
Male < 0.00 0.00–0.00 0.999
Incidental detection 0.21 0.02–2.34 0.208
Hypertension 4.80 0.54–42.63 0.159
Feeding artery diameter 0.80 0.34–1.86 0.608
Venous sac diameter 1.01 0.81–1.24 0.947
Types of PAVM < 0.00 0.00–0.00 0.999
Multivariate analysis
Age ≥ 65 17.09 1.16–250.31 0.038
HTN 7.68 0.47–125.23 0.152
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OR, odds ratio; CI, confidence interval; PAVM, pulmonary arteriovenous malformation

Fig 3 shows the Kaplan–Meier curve for the development of new cerebral complications in the ≥ 65 years and < 65 years age groups of patients who did not undergo treatment after a PAVM diagnosis. The older age group (≥65 years) was significantly associated with the development of cerebral complications during the follow-up period (log-rank P = 0.014).Multivariate Cox-regression analysis showed that the older age group (≥65 years) was associated with an increased risk of cerebral complications (hazard ratio, 18.00; 95% CI, 1.48–218.95; P = 0.023).

Fig 3. Kaplan–Meier curve illustrating the time without the development of new cerebral complications in untreated PAVM patients (n = 33).

Fig 3

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Discussion

We described the risk factors for cerebral complications in patients with PAVMs in this multicenter retrospective cohort study. The number of newly diagnosed PAVM patients is increasing; in particular, the number of patients diagnosed incidentally without symptoms has increased. Older age (≥ 65 years) was associated with increased cerebral complications. The untreated group tended to develop more cerebral complications during the follow-up period; however, there was no significant difference between the two groups. The older age group (≥65 years) was significantly associated with the development of cerebral complications during the follow-up period among patients who did not undergo treatment for PAVMs.

Most patients with PAVMs had respiratory symptoms according to Gossage et al. [3]. However, subsequent studies have reported that most patients with PAVMs are asymptomatic [4, 6–10]. In this study, 54.5% of patients with PAVMs were asymptomatic, and PAVMs were detected incidentally. In particular, the number of patients with incidentally detected PAVM had increased over time in the follow-up cohort. The increase in the number of patients with incidentally detected PAVM is most likely due to the incidental detection of PAVMs on chest imaging or during preoperative evaluations [6–10]. We found that the majority of patients (54%) were diagnosed with PAVM incidentally during similar health screenings. Transthoracic contrast echocardiography (TTCE) is recommended as a screening test for PAVMs in patients with a high risk of PAVMs or suspected right-to-left shunts [15, 19–21].The sensitivity and specificity of TTCE for detecting right-to-left shunts are high [19, 20, 22]. Compared to chest CT, TTCE does not expose the patient to radiation [15]. When a right-to-left shunt is confirmed with TTCE, a chest CT or angiography is performed to confirm the PAVM [15, 23]. Although Chest CT and TTCE examined together exhibit almost 100% sensitivity and negative predictive value [19, 20], it is unclear whether TTCE should be performed in patients withincidentally detected PAVMs on chest CT scans. In this study, only four patients (7.3%) underwent TTCE. Because additional TTCE may not be necessary in patients with PAVM detected incidentally on chest CT, further prospective studies are needed.

HHT is an autosomal dominant disease. Patients with PAVM account for 15% to 35% of all patients with HHT [15]. In North America and Europe, 60% to 80% of PAVM patients were found to have HHT [1–3]. In Japan, according to Shioya et al, patients with HHT and PAVMs accounted for 15% of PAVM patients [5]. Kim et al. reported that HHT-related PAVM occurred in 13% of cases in South Korea [4]. In the present study, there was only one patient with HHT. PAVM is rarely reported in Asia, which may be attributable to racial differences [15, 24]. In this retrospective study, HHT may have been underestimated in patients with PAVM. In order to avoid fatal complications, systematic education and training for the diagnosis and treatment of PAVMs in patients with HHT are needed [25].

Life-threatening complications of PAVMs include stroke, transient ischemic attack, cerebral abscess, and massive hemoptysis. Between 9% and 41% of patients with PAVMs develop cerebral complications, mainly stroke and cerebral abscess [6–11]. Patients with multiple PAVMs and older patients were at greater risk of cerebral complications [13, 14]. According to various studies, cerebral complications are more likely to occur in patients with PAVMs with feeding artery diameters greater than 3 mm [2, 13].Some previous reports suggest that cerebral complications are not directly related to feeding artery diametersize [9, 26]. Patients with feeding artery diameters of 2 mm are also recommended for treatment in the recent PAVM treatment guidelines [15]. There was no statistical significance between feeding artery diameter size and cerebral complications in this study. In patients over 65 years of age, the odds of developing cerebral complications were 16 times higher than that in patients under 65 years of age. In this study, incidentally detected PAVM patients had a lower risk of cerebral complications than symptomatic PAVM patients. Patients with symptomatic PAVM had more cerebral complications at the time of diagnosis (32.0% vs. 10.0%; P = 0.088). Additionally, three out of 15 untreated symptomatic PAVM patients developed cerebral complications, whereas one out of 18 untreated incidentally detected PAVM patients developed cerebral complications. The early detection of PAVM before complications develop may contribute to the low risk of cerebral complications in patients with incidentally detected PAVM.

The treatment of choice for patients with PAVMs is embolotherapy [1, 15, 21]. Surgical excision may be required when embolotherapy fails or pulmonary hemorrhage associated with PAVM rupture occurs [1, 15]. Embolotherapy improves oxygenation and exercise tolerance and decreases dyspnea, paradoxical embolization, strokes, migraines, and pulmonary hemorrhages [12]. Several studies have reported that PAVM treatment is associated with fewer cerebral complications [6, 9, 18, 26]. The untreated group had more cerebral complications than the treated group (P = 0.088) in this study. The treated group did not experience any cerebral complications during the follow-up period. In the older age group (≥ 65 years), the odds of developing cerebral complications were 18 times higher than in the younger age group (< 65 years) among patients who did not receive treatment after the PAVM diagnosis. Maher et al. also found that older patients with PAVM often experienced cerebral complications [14]. The high risk of cerebral complications in older patients with PAVMs should prompt them to seek active treatment.

This study had some limitations. First, this study was conducted retrospectively. Therefore, there is a limit to the generalizability of the findings. Second, there were very few patients with HHT compared with previous studies in this study. Because this is a retrospective study, HHT may have been underestimated. Third, a small number of 55 patients were enrolled in this 19-year retrospective study owing to the rarity of PAVM. Although we evaluated the functional disability associated with cerebral complications, the number of patients in this study was insufficient for statistical analysis. Therefore, prospective multicenter studies are required for a more robust evaluation. Fourth, diabetes and hypertension are well-known risk factors for stroke [27]. Hypertension and diabetes were not statistically significant in the univariate logistic regression analysis in this study. However, there were a few patients with hypertension or diabetes in this study cohort (11 with hypertension and three with diabetes). Fifth, the majority of strokes occur in people over 65. It is possible that observed cerebral complications cannot be definitively attributed to PAVM due to a small number of enrolled patients [28]. Therefore, multicenter studies that allow the inclusion of a larger number of patients with PAVMs are needed.

Conclusions

The number of patients newly diagnosed with PAVM, particularly the number diagnosed incidentally without symptoms, is increasing. Older age (≥65 years) was a risk factor for cerebral complications in patients with PAVMs; thus, treatment should be considered in older patients.

Supporting information

S1 File. Dataset.

(XLSX)

Click here for additional data file. (23.1KB, xlsx)
S1 Table. Characteristics of patients with cerebral complications.

(DOCX)

Click here for additional data file. (19KB, docx)

Data Availability

All relevant data are within the manuscript and its Supporting Information files.

Funding Statement

This study was supported by the National Research Foundation of Korea funded by the Korean Government (grant 2019R1F1A1060899). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

References

  • 1.Shovlin CL. Pulmonary arteriovenous malformations. Am J Respir Crit Care Med. 2014;190(11):1217–28. doi: 10.1164/rccm.201407-1254CI [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 2.White RI Jr., Lynch-Nyhan A, Terry P, Buescher PC, Farmlett EJ, Charnas L, et al. Pulmonary arteriovenous malformations: techniques and long-term outcome of embolotherapy. Radiology. 1988;169(3):663–9. doi: 10.1148/radiology.169.3.3186989 [DOI] [PubMed] [Google Scholar]
  • 3.Gossage JR, Kanj G. Pulmonary arteriovenous malformations. A state of the art review. Am J Respir Crit Care Med. 1998;158(2):643–61. doi: 10.1164/ajrccm.158.2.9711041 [DOI] [PubMed] [Google Scholar]
  • 4.Kim HJ, Lee JS, Oh YM, Shim TS, Lim CM, Koh YS, et al. Clinical characteristics of pulmonary arteriovenous malformations in Koreans. Respirology. 2015;20(1):155–9. doi: 10.1111/resp.12411 [DOI] [PubMed] [Google Scholar]
  • 5.Shioya T, Satake M, Uemura S, Iwakura M, Asano M, Okuda Y, et al. Comparison of PAVMs associated or not associated with hereditary hemorrhagic telangiectasia in the Japanese population. Respir Investig. 2015;53(6):300–4. doi: 10.1016/j.resinv.2015.06.004 [DOI] [PubMed] [Google Scholar]
  • 6.Mager JJ, Overtoom TT, Blauw H, Lammers JW, Westermann CJ. Embolotherapy of pulmonary arteriovenous malformations: long-term results in 112 patients. J Vasc Interv Radiol. 2004;15(5):451–6. doi: 10.1097/01.rvi.0000126811.05229.b6 [DOI] [PubMed] [Google Scholar]
  • 7.Pollak JS, Saluja S, Thabet A, Henderson KJ, Denbow N, White RI Jr., Clinical and anatomic outcomes after embolotherapy of pulmonary arteriovenous malformations. J Vasc Interv Radiol. 2006;17(1):35–44; quiz 5. [DOI] [PubMed] [Google Scholar]
  • 8.Cottin V, Chinet T, Lavole A, Corre R, Marchand E, Reynaud-Gaubert M, et al. Pulmonary arteriovenous malformations in hereditary hemorrhagic telangiectasia: a series of 126 patients. Medicine (Baltimore). 2007;86(1):1–17. doi: 10.1097/MD.0b013e31802f8da1 [DOI] [PubMed] [Google Scholar]
  • 9.Shovlin CL, Jackson JE, Bamford KB, Jenkins IH, Benjamin AR, Ramadan H, et al. Primary determinants of ischaemic stroke/brain abscess risks are independent of severity of pulmonary arteriovenous malformations in hereditary haemorrhagic telangiectasia. Thorax. 2008;63(3):259–66. doi: 10.1136/thx.2007.087452 [DOI] [PubMed] [Google Scholar]
  • 10.Angriman F, Ferreyro BL, Wainstein EJ, Serra MM. Pulmonary arteriovenous malformations and embolic complications in patients with hereditary hemorrhagic telangiectasia. Arch Bronconeumol. 2014;50(7):301–4. doi: 10.1016/j.arbres.2013.08.006 [DOI] [PubMed] [Google Scholar]
  • 11.Shin JH, Park SJ, Ko GY, Yoon HK, Gwon DI, Kim JH, et al. Embolotherapy for pulmonary arteriovenous malformations in patients without hereditary hemorrhagic telangiectasia. Korean J Radiol. 2010;11(3):312–9. doi: 10.3348/kjr.2010.11.3.312 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 12.Gupta P, Mordin C, Curtis J, Hughes JM, Shovlin CL, Jackson JE. Pulmonary arteriovenous malformations: effect of embolization on right-to-left shunt, hypoxemia, and exercise tolerance in 66 patients. AJR Am J Roentgenol. 2002;179(2):347–55. doi: 10.2214/ajr.179.2.1790347 [DOI] [PubMed] [Google Scholar]
  • 13.Moussouttas M, Fayad P, Rosenblatt M, Hashimoto M, Pollak J, Henderson K, et al. Pulmonary arteriovenous malformations: cerebral ischemia and neurologic manifestations. Neurology. 2000;55(7):959–64. doi: 10.1212/wnl.55.7.959 [DOI] [PubMed] [Google Scholar]
  • 14.Maher CO, Piepgras DG, Brown RD, Jr., Friedman JA, Pollock BE. Cerebrovascular manifestations in 321 cases of hereditary hemorrhagic telangiectasia. Stroke. 2001;32(4):877–82. [DOI] [PubMed] [Google Scholar]
  • 15.Faughnan ME, Palda VA, Garcia-Tsao G, Geisthoff UW, McDonald J, Proctor DD, et al. International guidelines for the diagnosis and management of hereditary haemorrhagic telangiectasia. J Med Genet. 2011;48(2):73–87. doi: 10.1136/jmg.2009.069013 [DOI] [PubMed] [Google Scholar]
  • 16.Biswas D, Dey A, Chakraborty M, Biswas S. Pulmonary arteriovenous malformation: An uncommon disease with common presentation. Lung India. 2010;27(4):247–9. doi: 10.4103/0970-2113.71965 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 17.Wilson JT, Hareendran A, Grant M, Baird T, Schulz UG, Muir KW, et al. Improving the assessment of outcomes in stroke: use of a structured interview to assign grades on the modified Rankin Scale. Stroke. 2002;33(9):2243–6. doi: 10.1161/01.str.0000027437.22450.bd [DOI] [PubMed] [Google Scholar]
  • 18.Lee DW, White R Jr., Egglin TK, Pollak JS, Fayad PB, Wirth JA, et al. Embolotherapy of large pulmonary arteriovenous malformations: long-term results. Ann Thorac Surg. 1997;64(4):930–9; discussion 9–40. doi: 10.1016/s0003-4975(97)00815-1 [DOI] [PubMed] [Google Scholar]
  • 19.Nanthakumar K, Graham AT, Robinson TI, Grande P, Pugash RA, Clarke JA, et al. Contrast echocardiography for detection of pulmonary arteriovenous malformations. Am Heart J. 2001;141(2):243–6. doi: 10.1067/mhj.2001.112682 [DOI] [PubMed] [Google Scholar]
  • 20.Cottin V, Plauchu H, Bayle JY, Barthelet M, Revel D, Cordier JF. Pulmonary arteriovenous malformations in patients with hereditary hemorrhagic telangiectasia. Am J Respir Crit Care Med. 2004;169(9):994–1000. doi: 10.1164/rccm.200310-1441OC [DOI] [PubMed] [Google Scholar]
  • 21.Majumdar S, McWilliams JP. Approach to Pulmonary Arteriovenous Malformations: A Comprehensive Update. J Clin Med. 2020;9(6). doi: 10.3390/jcm9061927 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 22.Gazzaniga P, Buscarini E, Leandro G, Reduzzi L, Grosso M, Pongiglione G, et al. Contrast echocardiography for pulmonary arteriovenous malformations screening: does any bubble matter? Eur J Echocardiogr. 2009;10(4):513–8. doi: 10.1093/ejechocard/jen317 [DOI] [PubMed] [Google Scholar]
  • 23.Burke CM, Safai C, Nelson DP, Raffin TA. Pulmonary arteriovenous malformations: a critical update. Am Rev Respir Dis. 1986;134(2):334–9. doi: 10.1164/arrd.1986.134.2.334 [DOI] [PubMed] [Google Scholar]
  • 24.Shovlin CL. Hereditary haemorrhagic telangiectasia: pathophysiology, diagnosis and treatment. Blood Rev. 2010;24(6):203–19. doi: 10.1016/j.blre.2010.07.001 [DOI] [PubMed] [Google Scholar]
  • 25.Shovlin CL, Gossage JR. Pulmonary arteriovenous malformations: evidence of physician under-education. ERJ Open Res. 2017;3(2). doi: 10.1183/23120541.00104-2016 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 26.Todo K, Moriwaki H, Higashi M, Kimura K, Naritomi H. A small pulmonary arteriovenous malformation as a cause of recurrent brain embolism. AJNR Am J Neuroradiol. 2004;25(3):428–30. [PMC free article] [PubMed] [Google Scholar]
  • 27.Alloubani A, Saleh A, Abdelhafiz I. Hypertension and diabetes mellitus as a predictive risk factors for stroke. Diabetes Metab Syndr. 2018;12(4):577–84. doi: 10.1016/j.dsx.2018.03.009 [DOI] [PubMed] [Google Scholar]
  • 28.Yousufuddin M, Young N. Aging and ischemic stroke. Aging (Albany NY). 2019;11(9):2542–4. doi: 10.18632/aging.101931 [DOI] [PMC free article] [PubMed] [Google Scholar]

Decision Letter 0

Alfred Pokmeng See

3 May 2022

PONE-D-22-08058Risk factors for cerebral complications in patients with pulmonary arteriovenous malformations: a multicenter retrospective cohort studyPLOS ONE

Dear Dr. Shin,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

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We look forward to receiving your revised manuscript.

Kind regards,

Alfred Pokmeng See, M.D.

Academic Editor

PLOS ONE

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Additional Editor Comments:

Dear Dr. Shin,

Thank you for your submission regarding cerebral complications of pulmonary AVMs. Two reviewers from different subspecialty backgrounds have considered the manuscript and offer meaningful suggestions. A central concern is the specification of neurologic complications and use of functional outcome metrics, which would be standard in stroke reporting. Not all "cerebral complications" are equivalent and they may be unrelated to the pulmonary AVM. The reviewers also provide useful suggestions to conform with typical reporting in clinical neurology research.

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Reviewers' comments:

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Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

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Reviewer #1: Partly

Reviewer #2: Partly

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

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Reviewer #1: Yes

Reviewer #2: Yes

**********

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Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Review Comments to the Author

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Reviewer #1: The authors seek to address an important issue in PAVM pathophysiology—the risk of developing cerebral complications—especially when the primary pathology is asymptomatic and incidental. The authors acknowledge their biggest limitation which is the small sample size of their population. Unfortunately, the small sample size underpowers their statistical analysis as can be seen in the wide range of their confidence interval. As such, I am concerned that their claims, especially with their subgroup analysis, is overstated. Nonetheless, this serves as a starting point for future studies. I would recommend that the authors strengthen their focus on the types of neurologic complications and highlight patient outcomes before this paper is suitable for acceptance.

Comments:

1. Study Design: I think the authors need to provide more details on how the patients were selected. Why were these patients with “incidental PAVMs” who are presumably asymptomatic scanned w a CT or pulmonary angiography? Would that introduce a population bias?

2. Results line 110-111: Since the authors want to describe the risk of cerebral complications w PAVMs, I think it is important for them to describe the types of cerebral complications they had in their populations. They only provide a binary description of symptomatic and incidentally detected.

3. Results line 115-116: Would recommend describing the complications that occurred in the patients who did not undergo treatment (were they considered more severe? Any pattern?)

4. Results line 115-116: The authors state a total of 13 pts had cerebral complications and of them, four patients did not undergo treatment. Subsequently, in line 117-118, they state that none of the patients who underwent treatment for PAVMs had cerebral complications. Please provide clarification or additional details on the remaining 9 patients with complications.

5. Would recommend providing a table detailing the demographics of the patients with cerebral complications and their outcomes

6. Table 2 reports several risk factors based on characteristics of PAVMs (feeding artery diameter, types of AVM) but does not report size or location which may be useful to include.

7. Figure 2: Is a Kaplan Meier survival curve the best choice in trying to highlight the morbidity of cerebral complications especially since there was no survival difference? It may be more meaningful to look at functional scales such as mRS or GOS.

8. Line 191: Missing the word echo for TTCE

Reviewer #2: In the conclusions section, there is no mention of the possibility that both hypertension and diabetes may also be a contributing factor given that one or other were present in all patients with cerebral complications with pAVM. Perhaps comment as to why it is not relevant or consider that in fact may well be.

**********

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Reviewer #1: No

Reviewer #2: No

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PLoS One. 2022 Dec 1;17(12):e0278610. doi: 10.1371/journal.pone.0278610.r002

Author response to Decision Letter 0

12 Jun 2022

PONE-D-22-08058

Risk factors for cerebral complications in patients with pulmonary arteriovenous malformations: a multicenter retrospective cohort study

PLOS ONE

Responses to reviewers

Reviewer #1: The authors seek to address an important issue in PAVM pathophysiology—the risk of developing cerebral complications—especially when the primary pathology is asymptomatic and incidental. The authors acknowledge their biggest limitation which is the small sample size of their population. Unfortunately, the small sample size underpowers their statistical analysis as can be seen in the wide range of their confidence interval. As such, I am concerned that their claims, especially with their subgroup analysis, is overstated. Nonetheless, this serves as a starting point for future studies. I would recommend that the authors strengthen their focus on the types of neurologic complications and highlight patient outcomes before this paper is suitable for acceptance.

A. Thank you for your precise and kind comments. This study only included a small number of participants because PAVM is a rare disease. We believe this study can serve as a starting point for diagnosing and treating of PAVM. We tried to strengthened the types and outcomes of neurologic complications, as you pointed out.

Q1. Study Design: I think the authors need to provide more details on how the patients were selected. Why were these patients with “incidental PAVMs” who are presumably asymptomatic scanned w a CT or pulmonary angiography? Would that introduce a population bias?

A1. Thank you for your comment. We screened patients with PAVM confirmed by diagnostic code, chest computed tomography (CT) findings, or pulmonary angiography findings during the study period. A total of 70 individuals were screened, of which 15 were excluded due to the following reasons: CT or angiography did not reveal PAVM (n = 11), and diagnosis of pulmonary sequestration (n = 3) or pulmonary venous anomaly (n = 1). A total of 55 patients with PAVM were enrolled in this study.

We added this information to method and results sections. See line 57-59 on page 4 and line 109-112 on page 7.

Q2. Results line 110-111: Since the authors want to describe the risk of cerebral complications w PAVMs, I think it is important for them to describe the types of cerebral complications they had in their populations. They only provide a binary description of symptomatic and incidentally detected.

A2. Thank you for your valuable comment. We added the types of complications in the results section, as your recommendation. See line 120-123 on page 7.

Q3. Results line 115-116: Would recommend describing the complications that occurred in the patients who did not undergo treatment (were they considered more severe? Any pattern?)

A3. Thank you for your valuable comments. Cerebral complication in all the four patients included strokes, and one of them showed severe functional impairments, with a mRS score of 5. The other three, however, only showed mild impairments with mRS scores of 1¬3. We added this information to method and results sections. See line 126-132 on page 7-8.

Q4. Results line 115-116: The authors state a total of 13 pts had cerebral complications and of them, four patients did not undergo treatment. Subsequently, in line 117-118, they state that none of the patients who underwent treatment for PAVMs had cerebral complications. Please provide clarification or additional details on the remaining 9 patients with complications.

A4. Thank you for your valuable comments. In this study, of the 13 patients with cerebral complications, 12 had stroke and one had a cerebral abscess; moreover, six developed cerebral complications before PAVM diagnosis, and five developed them concurrently with PAVM diagnosis. Among patients with untreated PAVM, four patients developed cerebral complications after diagnosis of PAVM, and two of those had previous cerebral complications. We modified the results section as your recommendation. See line 120-123 on page 7.

Q5. Would recommend providing a table detailing the demographics of the patients with cerebral complications and their outcomes

A5. Thank you for your comments. We added a S1 Table for 13 patients with cerebral complications. See S1 Table.

Q6. Table 2 reports several risk factors based on characteristics of PAVMs (feeding artery diameter, types of AVM) but does not report size or location which may be useful to include.

A6. Thank you for your valuable comments. PAVM locations and size of venous sac have been added to tables 1 and 2. However, both variables were not risk factors for development of cerebral complications in the univariate logistic regression analysis. See table 1 and 2 on page 8 and 11, respectively.

Q7. Figure 2: Is a Kaplan Meier survival curve the best choice in trying to highlight the morbidity of cerebral complications especially since there was no survival difference? It may be more meaningful to look at functional scales such as mRS or GOS.

A7. Thank you for your comments. Figure 2 shows a Kaplan-Meier curve of time without cerebral complications following treatment of pulmonary arteriovenous malformation. Although the untreated group developed more cerebral complications during the follow-up period, there was no significant difference between the two groups (log-rank P = 0.088). Due to the small number of patients enrolled, we did not consider the difference to be statistically significant.

Based on your opinion, we measured the modified Rankin Scale (mRS) of patients with cerebral complications after detection of PAVM. In four patients, cerebral complications developed after PAVM detection, and the mRS varied from 1, 1, 3, and 5, respectively, therefore the number of patients was insufficient for a statistical analysis. These findings have been added as limitation part. See line 260-262 page on 17.

Q8. Line 191: Missing the word echo for TTCE

A8. I appreciate your kind words. The error has been corrected.

Reviewer #2

Q1. In the conclusions section, there is no mention of the possibility that both hypertension and diabetes may also be a contributing factor given that one or other were present in all patients with cerebral complications with pAVM. Perhaps comment as to why it is not relevant or consider that in fact may well be.

A1. Thank you for your valuable comments. Diabetes and hypertension are well-known risk factors for stroke. In this study, we investigated whether diabetes and hypertension were risk factors for stroke among PAVM patients. Table 2 of this study shows risk factors associated with cerebral complications. Hypertension and diabetes were not statistically significant in univariate logistic regression analysis in this study. However, there were a few patients with hypertension or diabetes in this study cohort (11 with hypertension and three with diabetes). Therefore, multicenter studies that allow the inclusion of a larger number of patients with PAVMs are needed. This was added to the limitation. See line 263-267 on page 17.

Attachment

Submitted filename: Response to Reviewers.docx

Click here for additional data file. (21.6KB, docx)

Decision Letter 1

Alfred Pokmeng See

28 Jun 2022

PONE-D-22-08058R1Risk factors for cerebral complications in patients with pulmonary arteriovenous malformations: a multicenter retrospective cohort studyPLOS ONE

Dear Dr. Shin,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please submit your revised manuscript by Aug 12 2022 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

  • A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

  • A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

  • An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Alfred Pokmeng See, M.D.

Academic Editor

PLOS ONE

Journal Requirements:

Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

Additional Editor Comments:

Before requesting further input from the reviewers, please further address the following questions:

Reviewer 1

Q1 - The reviewer asks the medical rationale for workup and diagnosis of patients without symptoms that led to PAVM. In lines 57-59, you provide information on how these patients were identified from the medical record system, but not why they were evaluated with CT or angiography. "More than half of the enrolled patients were diagnosed with PAVMs incidentally without symptoms."

Q2. - The reviewer asks for more specifics of the type of cerebral complication, and you now explain stroke vs. abscess. More detail is likely appropriate again, from the perspective of this reviewer as a neuroscience expert. For example, presumably these are ischemic strokes, although hemorrhagic stroke may also be possible. Furthermore, in discussing cerebral complications at the time of diagnosis (13 patients), the authors now report 9 symptomatic vs 4 asymptomatic, and 12 strokes vs 1 abscess, but describe 6 before diagnosis and 5 at the time of diagnosis (adding up to 11, not 13). The characterization of complications before pAVM diagnosis merits further clarification in the methods. Are these prior strokes based on brain imaging (not described in methods)?

Furthermore, table 1 shows 4 patients with neurologic symptoms. How do these relate to the 9symptomatic/4asymptomatic or 6before/5concurrent proportions described in the prose?

Q2-4. - The reviewer asks for a more direct description of:

pAVM - presenting asymptomatically

pAVM - presenting with symptoms unrelated to the brain

pAVM - presenting with neurologic symptoms

pAVM untreated patients - risk of subsequent neurologic symptoms

pAVM treated patients - risk of subsequent neurologic symptoms

Part of the problem appears to be semantic. The authors use the same term, cerebral complication, to describe strokes before diagnosis, strokes which were the presenting symptom leading to diagnosis, and strokes which occur after diagnosis. These are then used in one large paragraph. A flow chart of the events or a timeline plot of events may provide better clarity. For example Figure 1 in https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7606530/

Q5. - S1 provides no legend for interpretation of the coded data or column names. For example, column D "Detect_reasons" has codes 1-9. The reader would benefit from seeing the 9 reasons that pAVM is presenting for evaluation. Table 1 only has 8 'causes of detection'

Reviewer 1 had some concerns about internal consistency of the data in the form presented. Improved clarity of the terminology and better specification of the timeline will likely benefit the manuscript before return to reviewers.

[Note: HTML markup is below. Please do not edit.]

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

PLoS One. 2022 Dec 1;17(12):e0278610. doi: 10.1371/journal.pone.0278610.r004

Author response to Decision Letter 1

22 Aug 2022

Responses to reviewers

Reviewer #1: The authors seek to address an important issue in PAVM pathophysiology—the risk of developing cerebral complications—especially when the primary pathology is asymptomatic and incidental. The authors acknowledge their biggest limitation which is the small sample size of their population. Unfortunately, the small sample size underpowers their statistical analysis as can be seen in the wide range of their confidence interval. As such, I am concerned that their claims, especially with their subgroup analysis, is overstated. Nonetheless, this serves as a starting point for future studies. I would recommend that the authors strengthen their focus on the types of neurologic complications and highlight patient outcomes before this paper is suitable for acceptance.

A. Thank you for your precise and kind comments. This study only included a small number of participants because PAVM is a rare disease. We believe this study can serve as a starting point for diagnosing and treating of PAVM. We tried to strengthened the types and outcomes of neurologic complications, as you pointed out.

Q1. Study Design: I think the authors need to provide more details on how the patients were selected. Why were these patients with “incidental PAVMs” who are presumably asymptomatic scanned w a CT or pulmonary angiography? Would that introduce a population bias?

A1. Thank you for your comment.

We screened patients with PAVMs using diagnostic code, chest computed tomography (CT) findings, or pulmonary angiography findings during the study period. A total of 70 individuals were screened, of which 15 were excluded for the following reasons: a CT or angiography did not reveal PAVM (n = 11), or they were diagnosed with pulmonary sequestration (n = 3) or a pulmonary venous anomaly (n = 1). Therefore, a total of 55 patients with PAVM were enrolled in this study. [See line 57-59 on page 4 and line 118-121 on page 7]

A definition of incidentally detected PAVM has been added to the method section as "Patients with incidentally detected PAVM were those whose PAVM was detected during a health screening, preoperative evaluation, or evaluation of other diseases, and presented asymptomatically. ". [See line 84-57 on page 5]

Thirty patients were incidentally detected PAVM due to health screening (n = 18), preoperative evaluation (n = 6), and evaluation of other diseases (n = 6) such as hepatocellular carcinoma, Sjogren syndrome, External MALToma, AOSD, back pain, or hoarseness. These findings have also been added to the results section [See line 127-129 on page 7]

Q2. Results line 110-111: Since the authors want to describe the risk of cerebral complications w PAVMs, I think it is important for them to describe the types of cerebral complications they had in their populations. They only provide a binary description of symptomatic and incidentally detected.

A2. Thank you for your valuable comment. There were 11 patients with cerebral ischemia and one patient with cerebral hemorrhage. We change the manuscript as “A total of thirteen patients (23.6%) had cerebral complications, including cerebral ischemia (n = 11), cerebral hemorrhage (n = 1), and cerebral abscess (n = 1).”. [See line 129-130 on page 7] We added the types of complications in the results section, as your recommendation. See line 120-123 on page 7.

Q3. Results line 115-116: Would recommend describing the complications that occurred in the patients who did not undergo treatment (were they considered more severe? Any pattern?)

A3. Thank you for your valuable comments. Cerebral complications occurred in four patients who did not undergo treatment after a PAVM diagnosis, and two patients had previous cerebral complications. Cerebral complications in all four patients included cerebral ischemia, and one patient showed severe functional impairments, with an mRS score of 5. The other three patients, however, only showed mild impairments with mRS scores of 1¬3 (S1 Table). We added this information to method and results sections. [See line 136-141 on page 7-8.

Q4. Results line 115-116: The authors state a total of 13 pts had cerebral complications and of them, four patients did not undergo treatment. Subsequently, in line 117-118, they state that none of the patients who underwent treatment for PAVMs had cerebral complications. Please provide clarification or additional details on the remaining 9 patients with complications.

A4. Thank you for your valuable comments.

A total of thirteen patients (23.6%) had cerebral complications, including cerebral ischemia (n = 11), cerebral hemorrhage (n = 1), and cerebral abscess (n = 1). Of the 13 patients with cerebral complications, six developed these complications before their PAVM diagnosis, five developed these complications concurrently with their PAVM diagnosis, and two developed these complications after their PAVM diagnosis.

Cerebral complications occurred in four patients who did not undergo treatment after a PAVM diagnosis, and two patients had previous cerebral complications.

We modified the results section as your recommendation. [See line 129-133 and 136-138 on page 7]

Q5. Would recommend providing a table detailing the demographics of the patients with cerebral complications and their outcomes

A5. Thank you for your comments. We added a S1 Table for 13 patients with cerebral complications. [See S1 Table]

Q6. Table 2 reports several risk factors based on characteristics of PAVMs (feeding artery diameter, types of AVM) but does not report size or location which may be useful to include.

A6. Thank you for your valuable comments. PAVM locations and size of venous sac have been added to tables 1 and 2. However, both variables were not risk factors for development of cerebral complications in the univariate logistic regression analysis. [See table 1 and 2 on page 8 and 11, respectively]

Q7. Figure 2: Is a Kaplan Meier survival curve the best choice in trying to highlight the morbidity of cerebral complications especially since there was no survival difference? It may be more meaningful to look at functional scales such as mRS or GOS.

A7. Thank you for your comments.

Figure 2 shows a Kaplan-Meier curve of time without cerebral complications following treatment of pulmonary arteriovenous malformation. Although the untreated group developed more cerebral complications during the follow-up period, there was no significant difference between the two groups (log-rank P = 0.088). Due to the small number of patients enrolled, we did not consider the difference to be statistically significant.

Based on your opinion, we measured the modified Rankin Scale (mRS) of patients with cerebral complications after detection of PAVM. In four patients, cerebral complications developed after PAVM detection, and the mRS varied from 1, 1, 3, and 5, respectively, therefore the number of patients was insufficient for a statistical analysis. These findings have been added as limitation part. [See line 272-276 page on 18].

Q8. Line 191: Missing the word echo for TTCE

A8. I appreciate your kind words. The error has been corrected.[See line 218 on page 15]

Reviewer #2

Q1. In the conclusions section, there is no mention of the possibility that both hypertension and diabetes may also be a contributing factor given that one or other were present in all patients with cerebral complications with pAVM. Perhaps comment as to why it is not relevant or consider that in fact may well be.

A1. Thank you for your valuable comments. Diabetes and hypertension are well-known risk factors for stroke. In this study, we investigated whether diabetes and hypertension were risk factors for stroke among PAVM patients. Table 2 of this study shows risk factors associated with cerebral complications. Hypertension and diabetes were not statistically significant in univariate logistic regression analysis in this study. However, there were a few patients with hypertension or diabetes in this study cohort (11 with hypertension and three with diabetes). Therefore, multicenter studies that allow the inclusion of a larger number of patients with PAVMs are needed. This was added to the limitation. See line 276-280 on page 18.

Responses to editor

Q1 - The reviewer asks the medical rationale for workup and diagnosis of patients without symptoms that led to PAVM. In lines 57-59, you provide information on how these patients were identified from the medical record system, but not why they were evaluated with CT or angiography. "More than half of the enrolled patients were diagnosed with PAVMs incidentally without symptoms."

A1. Thank you for your precise and kind comments.

A definition of incidentally detected PAVM has been added to the method section as "Patients with incidentally detected PAVM were those whose PAVM was detected during a health screening, preoperative evaluation, or evaluation of other diseases, and presented asymptomatically. ". [See line 84-57 on page 5]

Thirty patients were incidentally detected PAVM due to health screening (n = 18), preoperative evaluation (n = 6), and evaluation of other diseases (n = 6) such as hepatocellular carcinoma, Sjogren syndrome, External MALToma, AOSD, back pain, or hoarseness. These findings have also been added to the results section [See line 127-129 on page 7]

Q2-1- The reviewer asks for more specifics of the type of cerebral complication, and you now explain stroke vs. abscess. More detail is likely appropriate again, from the perspective of this reviewer as a neuroscience expert. For example, presumably these are ischemic strokes, although hemorrhagic stroke may also be possible.

A2-1. Thank you for your comments. There were 11 patients with cerebral ischemia and one patient with cerebral hemorrhage. We change the manuscript as “A total of thirteen patients (23.6%) had cerebral complications, including cerebral ischemia (n = 11), cerebral hemorrhage (n = 1), and cerebral abscess (n = 1).”. [See line 129-130 on page 7]

Q2-2. Furthermore, in discussing cerebral complications at the time of diagnosis (13 patients), the authors now report 9 symptomatic vs 4 asymptomatic, and 12 strokes vs 1 abscess, but describe 6 before diagnosis and 5 at the time of diagnosis (adding up to 11, not 13).

A2-2. Thank you for your comments.

It has caused confusion to use words such as "incidentally detected", "symptomatic", and "asymptomatic.". The term "asymptomatic patients" meant the same thing as incidentally detected patients.

We added the definition of incidentally detected PAVM on the method section. [See page 5, line 84-87] In addition, sentences with unclear meanings were removed. [See page 7, line 131-133], and see page 8, line 144-145 of revised manuscript with track change file]

The discussion section was also edited. [See line 213-217 on page 15]

Q2-3. The characterization of complications before pAVM diagnosis merits further clarification in the methods.

A2-3. Thank you for your comment. We added the clarification of cerebral complications to the method section as “The cerebral complications associated with PAVM were divided into cerebral ischemia, hemorrhage, and abscess.”. [See line 74-75 on page 4]

Q2-4. Are these prior strokes based on brain imaging (not described in methods)?

A2-4. Thank you for your comment. In order to determine whether there had been any brain complications before PAVM diagnosis, we reviewed the patient's medical records. However, brain CT or MRI was used to diagnose cerebral complications associated with PAVM at the time or after detected PAVM. We modified the method section as “A brain CT or MRI was used to diagnose cerebral complications associated with PAVM at the time of initial PAVM diagnosis or after PAVM was detected.” [See line 76-78 on page 5]

Q2-5. The reviewer asks for a more direct description of:

pAVM - presenting asymptomatically

pAVM - presenting with symptoms unrelated to the brain

pAVM - presenting with neurologic symptoms

pAVM untreated patients - risk of subsequent neurologic symptoms

pAVM treated patients - risk of subsequent neurologic symptoms

Part of the problem appears to be semantic. The authors use the same term, cerebral complication, to describe strokes before diagnosis, strokes which were the presenting symptom leading to diagnosis, and strokes which occur after diagnosis. These are then used in one large paragraph. A flow chart of the events or a timeline plot of events may provide better clarity. For example Figure 1 in https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7606530/

A2-5. Thank you for your valuable comments.

There was some confusion in the terminology we used, as you pointed out. In the method section, "PAVM presenting asymptomatically" is defined as “Patients with incidentally detected PAVM were those whose PAVM was detected during a health screening, preoperative evaluation, or evaluation of other diseases, and presented asymptomatically.”. [See line 85-57 on page 5]

In our study, we did not distinguish between PAVMs with symptoms unrelated to the brain and PAVMs with neurologic symptoms.

We clarified the cerebral complications associated with PAVM. We evaluated the risk factors for cerebral complications, including cerebral hemorrhage and ischemia, at the time of PAVM diagnosis (Table 2). Figure 2 shows the Kaplan–Meier curve for the development of new cerebral complications in the treated and untreated groups after PAVM diagnosis. We investigated the risk factors associated with new cerebral complications in 33 patients who did not receive treatment after their PAVM diagnosis (Table 3). Figure 3 shows the Kaplan–Meier curve for the development of new cerebral complications in the ≥ 65 years and < 65 years age groups of patients who did not undergo treatment after a PAVM diagnosis. The results section has been edited. [See line 159-160 on page 10, line 171-172 on page 12, line 177-183 on page 12, line 187-188 on page 13, line 191-193 on page 13, line 199-200 on page 14]

Despite your recommendation, we were not able to create a timeline plot because the timing of past cerebral complications was unclear (retrospective study).

Q3. - S1 provides no legend for interpretation of the coded data or column names. For example, column D "Detect_reasons" has codes 1-9. The reader would benefit from seeing the 9 reasons that pAVM is presenting for evaluation. Table 1 only has 8 'causes of detection'

A3. Thank you for your comments. We modified detect reasons of S1 files. The reason 1 and 2 are belongs to incidentally categories (1: health screening, 2: preoperative evaluation or other disease evaluations).

Attachment

Submitted filename: Response to Editor.docx

Click here for additional data file. (19.3KB, docx)

Decision Letter 2

Alfred Pokmeng See

24 Oct 2022

PONE-D-22-08058R2Risk factors for cerebral complications in patients with pulmonary arteriovenous malformations: a multicenter retrospective cohort studyPLOS ONE

Dear Dr. Shin,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

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Academic Editor

PLOS ONE

Journal Requirements:

Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

Additional Editor Comments:

Thank you for your revisions. Due to reviewer availability, additional reviewers were requested. They shared a similar concern regarding the possibility of comorbid risks for stroke in the older patient population. It would be appropriate to explicitly state in the limitations that the observed cerebral complications cannot be definitively linked to the PAVM, although this is assumed in the analysis.

For Table 3 the multivariate analysis section and the related results text only applies the statistical test (multivariate logistic regression) to a single variable (Age) therefore, it is not different from the univariate logistic regression, and logically, reports the same OR, CI, and p-value. Since no other co-variates were included in the 'multivariate' analysis, it is misleading to present this as a multivariate analysis and to re-present the data in a separate section of the table.

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Reviewers' comments:

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Reviewer #3: All comments have been addressed

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Reviewer #3: Cerebral and hemorrhagic complications associated with PAVMs are often fatal. This study retrospectively evaluated the risk factors for cerebral complications in patients with PAVMs. The included cerebral complications complications were stroke (12 cases) and brain abscess (one case ). The study was retrospective, and it is doubtful whether stroke is caused by PAVM in elderly patients.

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PLoS One. 2022 Dec 1;17(12):e0278610. doi: 10.1371/journal.pone.0278610.r006

Author response to Decision Letter 2

15 Nov 2022

<Response to editor>

Q1) Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

A1) Thank you for your comments. All references cited in this article have been thoroughly reviewed. We have also mentioned additional references below.

Additional Editor Comments:

Q2) Thank you for your revisions. Due to reviewer availability, additional reviewers were requested. They shared a similar concern regarding the possibility of comorbid risks for stroke in the older patient population. It would be appropriate to explicitly state in the limitations that the observed cerebral complications cannot be definitively linked to the PAVM, although this is assumed in the analysis.

A2) Thank you for your comments. We understand the concerns of reviewers and editors. We have added these concerns to the limitation section with reference as your suggestion. (See line 278-280 on page 18.)

Q3) For Table 3 the multivariate analysis section and the related results text only applies the statistical test (multivariate logistic regression) to a single variable (Age) therefore, it is not different from the univariate logistic regression, and logically, reports the same OR, CI, and p-value. Since no other co-variates were included in the 'multivariate' analysis, it is misleading to present this as a multivariate analysis and to re-present the data in a separate section of the table.

A3) Thank you for your valuable comments. We mentioned follows in the statistical analysis part of the methods section: Subsequent multivariate logistic regression analyses included variables with P values < 0.1 in the univariate analysis using a backward method. We changed the variable to be selected in univariate analysis from P <0.1 to P <0.2 in the same way as in Cox-regression analysis. As a result, age >65 and hypertension were selected in the univariate analysis. Table 3 shows the results of multivariate analysis with age >65 and hypertension. Additionally, diabetes was also selected in univariate analysis in Table 2. After multivariate analysis, the results are presented in table 2. (See line 34 on page 2, 110 on page 6, line 162-164 on page 10-11, table 2, line 185 on page 13, and table 3)

* Reference 21 has been added as a recent article. (See line 217-219 on page 15, and line 255 on page 17)

<Response to Reviewer #3>

Q1) Reviewer #3: Cerebral and hemorrhagic complications associated with PAVMs are often fatal. This study retrospectively evaluated the risk factors for cerebral complications in patients with PAVMs. The included cerebral complications complications were stroke (12 cases) and brain abscess (one case ). The study was retrospective, and it is doubtful whether stroke is caused by PAVM in elderly patients.

A1) Thank you for your valuable comments. In this study, we understand the concerns of older patients. The risk of stroke in elderly patients is well known. Further studies are needed to determine whether strokes are more common in elderly patients with pulmoanry AVMs. We have added these concerns to the limitation section. (See line 278-280 on page 18.)

Attachment

Submitted filename: Response to editor and reviewer.docx

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Decision Letter 3

Alfred Pokmeng See

21 Nov 2022

Risk factors for cerebral complications in patients with pulmonary arteriovenous malformations: a multicenter retrospective cohort study

PONE-D-22-08058R3

Dear Dr. Shin,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Kind regards,

Alfred Pokmeng See, M.D.

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Please correct the grammatical error in the revision:

Fifth, majority of strokes occur in people over 65.

Fifth, the majority of strokes occur in people over 65.

Reviewers' comments:

Acceptance letter

Alfred Pokmeng See

23 Nov 2022

PONE-D-22-08058R3

Risk factors for cerebral complications in patients with pulmonary arteriovenous malformations: a multicenter retrospective cohort study

Dear Dr. Shin:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

If we can help with anything else, please email us at plosone@plos.org.

Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Dr. Alfred Pokmeng See

Academic Editor

PLOS ONE

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