Prognostic factors and outcomes of acute type A aortic dissection: a retrospective clinical study

Abstract

Background

Acute type A aortic dissection (aTAAD) is a cardiovascular emergency requiring surgical intervention. Data on the long-term mortality of surgically treated patients remain scarce. We aimed to examine the prognostic factors and long-term outcomes of surgically treated patients with aTAAD.

Methods

We analyzed data from 952 surgically treated aTAAD patients. The association between the perioperative factors and long-term mortality of these patients was examined.

Results

Altogether, 93 patients died during the follow-up period, resulting in a 5-year mortality rate of 9.7%. The patients who died were older (P=0.02), had averagely higher European System for Cardiac Operative Risk Evaluation (EuroSCORE) II scores (P=0.042), longer cardiopulmonary bypass time (CPBT) (P=0.003), and tended to have postoperative kidney dysfunction (P=0.002) and postoperative cerebral accident (P=0.01). Univariate analysis revealed that age, intensive care unit stay, ventilation use, CPBT, albumin (both at admission and post-surgery), and creatinine (post-surgery) were also significantly associated with long-term mortality. After adjusting for the EuroSCORE II score in the multivariate analysis, only low albumin (both at admission and post-surgery) and high creatinine (post-surgery) levels remained as independent predictors of long-term mortality.

Conclusions

The EuroSCORE II score could be useful in predicting the long-term mortality of surgically treated aTAAD patients. Low albumin (both at admission and post-surgery) and high creatinine (post-surgery) levels are also important predictors.

Highlight box.

Key findings

• The 5-year mortality rate for surgically treated acute type A aortic dissection (aTAAD) patients was 9.7%.

• Independent predictors of long-term mortality were: (I) low albumin levels (both at admission and post-surgery); (II) high creatinine levels (post-surgery); (III) the European system for cardiac operative risk evaluation (EuroSCORE II score). They showed predictive value for long-term mortality.

What is known and what is new?

• aTAAD requires urgent surgery, but predictors of long-term outcomes remain unclear.

• This study identifies perioperative albumin, creatinine, and EuroSCORE II as key predictors of long-term mortality after aTAAD surgery.

What is the implication, and what should change now?

• Monitoring and optimizing albumin and creatinine levels during the perioperative period could improve long-term outcomes.

• The EuroSCORE II score should be integrated into preoperative risk assessment for aTAAD patients.

• Future studies should focus on interventions targeting these prognostic factors to reduce long-term mortality.

• Guidelines should emphasize the significance of nutritional and renal status in managing aTAAD patients.

Introduction

Acute type A aortic dissection (aTAAD) is a lethal cardiovascular condition characterized by a high mortality rate (1). It occurs when a tear in the intimal layer of the aorta allows blood to enter into the medial layer, creating a false lumen that can lead to life-threatening complications. Without performing any surgical intervention, the risk of death escalates rapidly by 1–2% per hour, with 50% of patients succumbing within the first 24 hours post-diagnosis based on the data from the 1950s (2). Similarly, a 2024 study by Teurneau-Hermansson et al. reported a 24-hour mortality rate of 47.3% and an hourly mortality rate of 2.6% in patients who did not undergo surgical treatment (3). Although the advancements in early diagnosis and emergency surgical techniques have improved patient outcomes, aTAAD remains a critical challenge in the field of cardiovascular medicine. Recent data have indicated a slightly improved mortality rate of 0.5% per hour, with a mortality rate at 48 hours of 23.7% (4).

Surgical repair, typically involving the replacement of the affected aortic segment, is a crucial life-saving procedure for those with aTAAD. However, the postoperative mortality and complication incidence rates remain considerably high. The surgical mortality rate of aTAAD patients ranges from 11% to 25% (5-8). Previous studies revealed that the short-term in-hospital mortality rates of aTAAD were between 10.2% and 24.3% (9-11), whereas the long-term survival rates were 96.1% and 90.5% at 1 and 3 years, respectively (12). These statistics underscore the critical need for improvements in both the surgical techniques and perioperative care to reduce mortality and enhance patient outcomes.

Despite the considerable advancements in surgical management, the high mortality and complication rates associated with aTAAD highlight the need for developing better prognostic tools to assess patient risk. Developing prognostic prediction models holds great promise for enabling clinicians to identify patients at a high risk of postoperative mortality and devise effective strategies for enhancing the survival rates. At present, there is little information on the predictors of long-term survival after discharge. Most existing studies have focused on in-hospital mortality predictors, highlighting parameters such as elevated aspartate transaminase (AST) levels, aortic cross-clamping time (ACCT) of >120 minutes (10), and higher preoperative systemic inflammatory index (8) as being linked to increased mortality.

A notable gap remains in identifying the factors that predict long-term survival after hospital discharge. Understanding these factors is crucial for optimizing long-term management and follow-up strategies for aTAAD patients. Additionally, insights into the long-term survival can contribute to the development of targeted interventions to improve the quality of life and reduce recurrence or complications among survivors. The present study aimed to assess the long-term survival rates of patients with aTAAD following hospital discharge and to delineate the clinical differences between those who survived and those who did not during the follow-up period. By identifying and understanding the factors that contribute to the long-term outcomes, clinicians can tailor the treatment and monitoring strategies to improve the survival rates and quality of life of these patients.

Furthermore, the novelty of this study lies in its focus on the long-term outcomes and survival predictors of aTAAD, an area that remains underexplored in current literature. By analyzing a comprehensive range of clinical, biochemical, and procedural variables, the present research seeks to fill existing knowledge gaps and provide a robust framework for assessing long-term risks. Our study findings could pave the way for personalized medicine approaches in aTAAD treatment, potentially transforming how patients are managed after initial hospital discharge and during follow-up care. Through this research, we hope to contribute to the ongoing efforts to reduce the mortality risk and improve the long-term outcomes of patients with aTAAD. Hence, this study was conducted to determine the prognostic factors and outcomes of patients with aTAAD. We present this article in accordance with the STROBE reporting checklist (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2024-2213/rc).

Methods

Study design and patient selection

The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. Given that the present study was a retrospective investigation utilizing existing data, obtaining ethics approval was not required, in line with the Fuwai Hospital’s guidelines for retrospective analyses involving anonymized data. Individual consent for this retrospective analysis was waived.

This retrospective analysis examined consecutive patients with aTAAD treated at Fuwai Hospital, a leading cardiovascular center, from March 2019 to April 2024. The study was designed to assess the long-term survival and factors influencing the outcomes of aTAAD patients who survived the initial hospitalization. Patient data were sourced from the hospital’s electronic medical records, including discharge diagnoses as well as imaging and surgical databases. The diagnosis of aTAAD was confirmed through imaging studies, including computed tomography angiography or magnetic resonance imaging, surgical visualization during operative repair, or autopsy findings.

Patients who succumbed during hospitalization were excluded from the analysis (n=84), with the analysis focused only on the 952 patients who were discharged alive. The inclusion criteria were as follows: patients diagnosed with aTAAD, defined as any non-traumatic dissection involving the ascending aorta presenting within 14 days of symptom onset (13,14); and those who underwent surgical repair and survived to discharge. The exclusion criteria for this study included cases of traumatic aortic dissection, patients who died during the initial hospital stay, and those with preoperative end-stage renal disease requiring chronic dialysis. The latter were excluded to ensure that the analysis focused solely on new-onset postoperative renal failure and to minimize potential confounding from preexisting renal dysfunction.

The median follow-up period of the present study was 3.6 years, at the last data point of the study, the follow-up rate was 85.5%, allowing for the assessment of the long-term survival outcomes. Given that the present study was a retrospective investigation utilizing existing data, obtaining ethics approval was not required, in line with the hospital’s guidelines for retrospective analyses involving anonymized data.

Study setting

Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences, is renowned for its specialized cardiovascular care and research. It serves as a referral center for complex aortic conditions, including aTAAD, providing comprehensive services from emergency diagnosis to surgical intervention and postoperative care.

Sample size calculation

Given the retrospective nature of the study, a formal sample size calculation was not performed before data collection. However, our analysis included all consecutive patients who met the inclusion criteria during the study period, ensuring that the sample was representative of the hospital’s aTAAD population. This approach maximized the use of the available data to enhance the study’s power and generalizability.

Sampling

Patients were selected consecutively based on their admission records and discharge diagnosis of aTAAD. Using the consecutive sampling method minimize selection bias and ensure that the study population accurately reflected the diversity of patients treated for aTAAD at the institution.

Data collection process

Data were extracted from the hospital’s electronic health records by trained clinical researchers. The data collection process involved multiple steps.

Identification of eligible patients

Patients were identified using the hospital’s electronic discharge diagnosis codes for aTAAD.

Verification of diagnosis

Each case was reviewed to confirm the diagnosis using imaging reports, surgical notes, and autopsy findings where applicable.

Data extraction

The pre-, intra-, and postoperative parameters were extracted from the electronic records. These parameters were as follows: preoperative parameters [age, sex, history of hypertension, European System for Cardiac Operative Risk Evaluation (EuroSCORE) II score, albumin (Alb) level, blood creatinine (Cr) level, blood urea nitrogen (BUN) level, alanine aminotransferase (ALT) level, AST level, history of surgery, coronary heart disease, diabetes, hyperlipidemia, chronic obstructive pulmonary disease, chronic renal failure, and smoking history]. These parameters were documented by physicians and nurses upon patient admission; intraoperative parameters [ACCT and cardiopulmonary bypass time (CPBT) were recorded by perfusionists during surgery]; and postoperative parameters [Alb, Cr, and BUN levels immediately after surgery, intensive care unit (ICU) stay duration, postoperative liver dysfunction, postoperative kidney dysfunction, and cerebrovascular accidents].

Operational definitions

• ❖ aTAAD: a non-traumatic dissection of the ascending aorta presenting within 14 days of symptom onset, confirmed by imaging or surgical findings.

• ❖ EuroSCORE II: a risk model used to predict mortality from cardiac surgery, incorporating patient-related factors and surgical variables.

• ❖ Postoperative liver dysfunction: an increase in liver enzymes (ALT and AST) beyond twice the normal upper limit within the first week post-surgery.

• ❖ Postoperative kidney dysfunction: an increase in the serum Cr level by >0.3 mg/dL or the need for renal replacement therapy post-surgery.

• ❖ Mortality following hospital discharge: the primary endpoint, defined as death occurring after a patient was discharged alive from the hospital following surgery.

Outcome measurement

The primary outcome measure was mortality following hospital discharge, assessed through follow-up visits and telephone interviews. The secondary outcomes included postoperative complications, including liver dysfunction, kidney dysfunction, and cerebrovascular accidents. To ensure accuracy, mortality data were corroborated using the national death registry when available.

Statistical analysis

All statistical analyses were conducted using SPSS software version 24 and GraphPad Prism version 10.1.2. Descriptive statistics were used to summarize the baseline characteristics and other relevant clinical parameters of the study population. Continuous variables were expressed as mean ± standard deviation for normally distributed data and median with interquartile range (IQR) for non-normally distributed data. The normality of continuous variables was assessed using the Shapiro-Wilk test. Categorical variables were presented as frequencies and percentages.

Comparative analyses between groups were conducted using the Chi-squared test and independent t-test for categorical and continuous variables, respectively. For continuous variables that did not meet the assumption of normality, the Mann-Whitney U test was employed instead.

The Cox proportional hazards model was utilized for both univariate and multivariable regression analyses to identify the predictors of long-term mortality. Prior to using the Cox model, the proportional hazard assumption was tested using Schoenfeld residuals and graphical diagnostics, such as log-minus-log plots. If any violations of the proportional hazards’ assumption were detected, appropriate stratification or time-dependent covariates were employed to address these issues.

Survival rates were estimated using the Kaplan-Meier method, providing a graphical representation of the survival probabilities over time. The differences in survival rates between groups were compared using the Mantel-Cox log-rank test, which evaluates the null hypothesis that there is no difference in the survival rate between the groups.

The results of the Cox regression analyses were interpreted in terms of hazard ratios (HRs) with 95% confidence intervals (CI). A HR of >1 indicated an increased risk of the event (mortality) occurring, whereas a HR of <1 indicated a decreased risk. Statistical significance was determined using a two-sided P value of <0.05.

Results

Patients’ characteristics

Altogether, the data of 952 surgically treated aTAAD patients were analyzed. The patients’ demographic and disease characteristics are summarized in Table 1. The mean hospitalization time was 14.2±7.5 days. Patients who died post-hospital discharge were on average older (P=0.02), had averagely higher EuroSCORE II scores (P=0.042), longer CPBT (P=0.003), and tended to have postoperative kidney dysfunction (P=0.002) and postoperative cerebral accidents (P=0.01). Overall, 93 patients died during the follow-up period.

Table 1. Baseline characteristics of the study participants (N=952).

Variables	Survived (n=859)	Died (n=93)	P value
Hospitalization (days)	14.3±7.6	14.4±7.7	0.53
Preoperative variables
Age (years)	50.7±11.9	54.2±13.3	0.02
Male	616 (71.7)	65 (69.9)	0.71
EuroSCORE II (%)	6.3±2.8	8.2±3.3	0.042
History of surgery	145 (16.9)	18 (19.4)	0.75
History of CHD	72 (8.4)	8 (8.6)	>0.99
Hypertension	620 (72.2)	65 (69.9)	0.74
Diabetes	41 (4.8)	5 (5.4)	0.82
Hyperlipidemia	332 (38.6)	39 (41.9)	0.75
History of COPD	9 (1.0)	2 (2.2)	0.58
History of CRF	15 (1.7)	5 (5.4)	0.06
Smoking	354 (41.2)	31 (33.3)	0.28
Total albumin (g/L)	36.9±10.9	38.1±20.1	0.60
AST (U/L)	45.6±88.9	54.3±95.1	0.63
ALT (U/L)	39.5±92.2	45.0±83.7	0.73
Cr (μmol/L)	115.9±61.5	127.7±121.7	0.12
BUN (mmol/L)	9.9±9.2	9.5±3.5	0.67
Intraoperative variables
CPBT (min)	65.2±36.6	78.7±54.5	0.003
ACCT (min)	109.4±44.7	112.4±41.7	0.68
Postoperative variables
Post-op kidney dysfunction	206 (24.0)	38 (40.9)	0.002
Post-op liver dysfunction	21 (2.4)	5 (5.4)	0.24
Cerebrovascular accident	9 (1.0)	6 (6.5)	0.01
Albumin (g/L)	34.4±5.3	33.1±6.2	0.054
Creatinine (μmol/L)	129.6±69.9	139.1±71.7	0.22
BUN (mmol/L)	11.2±7.8	11.4±3.9	0.59

Data are presented as No. (%) or mean ± standard deviation. ACCT, aortic cross-clamp time; ALT, alanine aminotransferase; AST, aspartate aminotransferase; BUN, blood urea nitrogen; CHD, coronary heart disease; COPD, chronic obstructive pulmonary disease; CPBT, cardiopulmonary bypass time; Cr, blood creatinine; CRF, chronic renal failure; EuroSCORE, European System for Cardiac Operative Risk Evaluation.

EuroSCORE II score and mortality

The EuroSCORE II score of the patients ranged from 1 to 15. Table 2 shows the percentage of death by EuroSCORE II scores. Mortality gradually increased with increasing EuroSCORE II scores. Figure 1 demonstrates that the post-hospital discharge survival rate of all the patients significantly varied when stratifying the patients by EuroSCORE II scores, with patients with a score of >8% having a significantly lower post-hospital discharge survival rate (87.3%) than in those with EuroSCORE II scores between 5–8% (93.7%) and 0–4% (98.9) (P=0.04).

Table 2. Frequency and percentage distribution of the EuroSCORE ranges in terms of mortality.

EuroSCORE II (%)	Total	Deaths	Percentage
0–4	244	14	5.7
5–8	372	33	8.8
>8	336	46	13.7
Total	952	93	9.8

EuroSCORE, European System for Cardiac Operative Risk Evaluation.

Figure 1.

The survival probability of surgically treated type A aortic dissection patients according to the EuroSCORE II scores. EuroSCORE, European System for Cardiac Operative Risk Evaluation.

Univariate analysis

Stratifying the patients by their EuroSCORE II scores, Table 3 shows that, compared to patients with scores of <4, those with higher scores had significantly higher rates of post-hospital discharge mortality in the unadjusted model [score 5–8: HR =2.19 (95% CI: 1.08–4.71), P=0.03; score >8: HR =5.10 (95% CI: 2.89–8.33), P<0.001]. Besides the EuroSCORE II score, age, ICU stay, ventilation use, CPBT, and Alb (both at admission and after surgery), and Cr (after surgery) levels were also significantly associated with a higher post-hospital discharge mortality rate in the univariable analysis (Table 3).

Table 3. Univariable analysis showing the risk factors of post-hospital discharge mortality among the surgically treated aTAAD patients (N=952).

Risk factor	HR (95% CI)	P value
EuroSCORE II (%)
Score 0–4	Ref	Ref
Score 5–8	2.19 (1.08–4.71)	0.03
Score >8	5.10 (2.89–8.33)	<0.001
Female	1.40 (0.80–2.50)	0.20
Age (years)	1.04 (1.02–1.07)	0.001
ICU stay (days)	1.05 (1.02–1.07)	<0.001
Ventilator use (days)	1.002 (1.001–1.003)	<0.001
Aortic diameter
<32 mm	Ref
≥32 mm	1.68 (0.09–7.94)	0.61
EF
EF (55−75%)	Ref
EF (<55%)	0.66 (0.04–3.10)	0.68
PLT
PLT (150–300/μL)	Ref
PLT <150/μL	1.28 (0.54–2.81)	0.55
PLT >300/μL	1.01 (0.16–3.52)	0.99
CPBT (min)	1.01 (1.00–1.01)	<0.001
ACCT (min)	0.99 (0.98–1.00)	0.12
Albumin
At admission (<25 g/dL)	3.17 (1.10–7.24)	0.01
After surgery (<25 g/dL)	4.11 (1.69–8.60)	<0.001
Creatinine
At admission (>115 μmol/L)	0.68 (0.39–1.20)	0.17
After surgery (>115 μmol/L)	3.54 (1.94–6.91)	<0.001
BUN
At admission (>8.2 mmol/L)	1.42 (0.80–2.63)	0.24
After surgery (>8.2 mmol/L)	1.92 (0.98–4.22)	0.08

ACCT, aortic cross-clamping time; aTAAD, acute type A aortic dissection; BUN, blood urea nitrogen; CI, confidence interval; CPBT, cardiopulmonary bypass time; EF, ejection fraction; EuroSCORE, European System for Cardiac Operative Risk Evaluation; HR, hazard ratio; ICU, intensive care unit; PLT, blood platelet level.

Multivariable analysis

In the multivariable analysis (Table 4), using variables that were significant in the univariate analysis, including age, ICU stay, ventilation use, CPBT, Alb level, and post-surgery Cr level, we found that age and Alb (both at admission and post-surgery) and Cr (post-surgery) levels were independent predictors of post-hospital discharge mortality (Model 1). After adjusting for the EuroSCORE II score (Model 2), Alb (both at admission and post-surgery) and Cr (post-surgery) remained as significant predictors.

Table 4. Multivariable analysis showing the risk factors of post-hospital discharge mortality among the surgically treated aTAAD patients (N=952).

Risk factor	HR (95% CI)	P value
Model 1
Age (years)	1.03 (1.01–1.06)	0.01
ICU stay (days)	0.96 (0.87–1.04)	0.34
Ventilation use (days)	1.00 (0.99–1.01)	0.08
CPBT	1.00 (0.99–1.01)	0.052
Albumin at admission (<25 g/dL)	2.93 (0.97–7.11)	0.03
Albumin after surgery (<25 g/dL)	2.88 (1.06–6.62)	0.02
Creatinine after surgery (>115 μmol/L)	2.77 (1.39–5.82)	0.004
Model 2
EuroSCORE II (%)	1.24 (0.09–1.41)	0.001
Score 0–4	Ref	Ref
Score 5–8	1.88 (0.87–3.11)	0.02
Score >8	3.23 (1.51–5.22)	0.01
Albumin at admission (<25 g/dL)	3.16 (0.92–8.16)	0.03
Albumin after surgery (<25 g/dL)	2.81 (1.04–6.44)	0.02
Creatinine after surgery (>115 μmol/L)	4.16 (2.00–9.49)	<0.001

Model 1: adjusted for age (years), ICU stay (days), ventilation use (days), CPBT (min), albumin at admission (<25 g/L), albumin after surgery (<25 g/L), and creatinine after surgery (>115 µmol/L); Model 2: Model 1 plus EuroSCORE II risk category (0–4%, 5–8%, >8%). aTAAD, acute type A aortic dissection; CI, confidence intervals; CPBT, cardiopulmonary bypass time; EuroSCORE, European System for Cardiac Operative Risk Evaluation; HR, hazard ratio; ICU, intensive care unit.

Receiver operating characteristic (ROC) curve analysis

The ROC curve analysis was performed to determine the optimal cut-off values for the pre- and postoperative blood Alb and postoperative blood Cr levels to identify the mortality risk of aTAAD patients (Figure 2). Our study results showed that only high postoperative blood Cr levels [area under the curve (AUC): 0.632], was associated with post-hospital discharge mortality in patients with aTAAD. The optimal cut-off value was 115 with a sensitivity of 65.8% and a specificity of 43.1%.

Figure 2.

ROC curves of the preoperative and postoperative blood albumin levels and postoperative blood creatinine levels to identify the mortality risk of aTAAD patients. Diagonal segments are produced by ties. Alb, albumin; aTAAD, acute type A aortic dissection; Creat, creatinine; ROC, receiver operating characteristic.

Discussion

To date, aTAAD remains a cardiovascular emergency necessitating immediate surgical intervention. Even with the advancements in surgical methods, the condition remains highly fatal, with in-hospital mortality rates ranging from 10.6% to 26.6% (3,5-10), although the data on long-term survival remain limited. It is, thus, important to identify all high-risk patients so that future clinical trials could focus on developing innovative surgical techniques and improving the survival outcomes of these patients.

In the present study, we examined the outcomes of 952 aTAAD patients who underwent surgical treatment at our hospital. The post-hospital discharge mortality rate was 9.7% after 5 years which was consistent with the data of Ogami et al. (12) and Obel et al. (15), but it was much lower than those of Nappi et al. (11) and Sadi et al. (16). This difference may be due to the continuous advancements in thoracic and heart surgical techniques and the general perioperative management of patients. Moreover, Heuts et al. found that PAR significantly reduced early mortality and the incidence of postoperative renal failure, although it had limited impact on stroke and long-term survival; a survival benefit of TAR was observed at 10-year follow-up (17). We noted that the EuroSCORE II score could be effective in predicting the long-term mortality, in conjunction with blood Alb levels at admission and post-surgery, and Cr levels post-surgery, which were also found to be independent predictors.

The EuroSCORE II is a scoring system used to estimate the risk of mortality in patients undergoing cardiac surgery (18). It is a refined version of the original EuroSCORE, designed to provide more accurate risk assessments by considering a broader range of patient and procedural variables. It is a well-validated and widely used scoring system that is utilized to predict cardiac surgical practices and outcomes. A recent study (19) comparing the predictive power of the EuroSCORE II for 30-day mortality of aTAAD patients with that of the German Registry of Acute Aortic Dissection Type A (GERAADA) (20) showed that the predictive ability of the EuroSCORE II (AUC 0.708, 95% CI: 0.664–0.792) was superior to that of the GERAADA score (0.648, 95% CI: 0.605–0.692). In addition, a recent study has also indicated that the GERAADA score demonstrates moderate discriminative ability and good calibration in predicting in-hospital mortality, with better calibration performance compared to the EuroSCORE II (21). However, no study has looked at its predictive ability beyond 30 days, either alone or in combination with other factors. In the present study, the patients’ mortality rate increased significantly as the EuroSCORE II score increased. Of all the variables related to EuroSCORE II, we entered age, sex, blood Cr level, aortic diameter, and ejection fraction (EF) into the univariate and multivariate analyses. Only blood Cr level of >115 µmol/L was associated with long-term mortality among aTAAD patients in the multivariate analysis. Therefore, the EuroSCORE II score and blood Cr level post-surgery need to be further evaluated in future studies.

Among the other preoperative biomarkers, low blood Alb level at admission (Alb <25 g/L) was an independent predictor of long-term mortality in addition to the EuroSCORE II score. One study on in-hospital mortality of aTAAD patients revealed that preoperative hypoalbuminemia was a key mortality predictor (22), whereas another study (23) related it to acute kidney injury and mortality in aTAAD patients. Hypoalbuminemia in cardiac patients is related to malnutrition, inflammation, and cachexia (24). This becomes more prevalent with old age and disease severity. Available evidence suggests that albuminemia and smoking, in conjunction with hypertension, are significantly associated with acute aortic dissection (22,25), including type B aortic dissection (26). An abnormal baseline blood Alb level may thus indicate pre-existing liver disease or organ ischemia during TAAD. In this study, the post-surgery blood Alb levels were still low. These findings thus suggest that liver protection should be prioritized in surgically treated aTAAD patients.

TAAD surgeries are technically challenging and require CPB. In our study, CPBT was a significant predictor of mortality in the univariate analysis, but it lost its significance after adjusting for the EuroSCORE II score (HR =1.004, 95% CI: 0.999–1.008, P=0.052), whereas ACCT was not a significant predictor in the univariate analysis. This contrasts with the findings of Wen et al. (10), who identified ACCT, rather than CPBT, as a significant predictor. However, our correlation analysis also showed a strong correlation between CPBT and ACCT (r=0.672; P<0.001), indicating that both may be important predictors. A prolonged CPBT suggests technical difficulties and/or complications during surgery, which can influence patient outcomes, such as longer ICU stays (27), extended ventilation use, and postoperative renal impairment (28,29), all of which could contribute to mortality.

The present study has several notable strengths. First, it utilized a large sample size of 952 aTAAD patients and the study was conducted over a 5-year period, providing robust data for analysis and ensuring the results are statistically significant and meaningful. The extensive dataset allowed for a thorough investigation of both preoperative and postoperative factors influencing the long-term outcomes. Another strength of the is its focus on the long-term outcomes, which distinguishes it from many previous studies that primarily focused on short-term mortality. By examining the predictors of long-term survival, this research addresses a critical gap in the existing literature and offers insights into patient management beyond the immediate postoperative period.

Additionally, the present study highlights the utility of the EuroSCORE II in predicting long-term mortality, demonstrating its potential application beyond traditional short-term risk assessment. By analyzing its predictive power in conjunction with other clinical parameters, the present study advances the understanding of how this tool can contribute to the development of effective patient care strategies. Furthermore, the multifactorial analysis, combining univariate and multivariable Cox regression analyses, allowed for a nuanced understanding of how various factors contribute to long-term mortality, identifying independent predictors and potential targets for intervention. Finally, conducting the study in a high-volume cardiovascular center ensures that the findings reflect real-world clinical practices and outcomes, enhancing the generalizability to similar healthcare settings.

Although rigorous efforts were made to ensure data completeness and accuracy, the inherent limitations of retrospective analyses remain. Additionally, as a single-center study, our study findings may not be universally applicable across different healthcare systems or patient populations. The differences in surgical techniques, perioperative care, and patient demographics may influence the generalizability of the results. Moreover, the absence of randomization limits the ability to establish causal relationships between the identified risk factors and long-term mortality. The confounding variables not accounted for in the analyses could potentially influence the observed associations. Finally, although the study provides valuable insights into the long-term outcomes, the follow-up period, although comprehensive, may not capture the late mortality or complications beyond 5 years post-discharge.

Furthermore, cause-specific mortality data were not uniformly available during follow-up, precluding analyses such as Kaplan-Meier curves for cardiovascular-related deaths. Second, frailty—a known prognostic factor in elderly patients—could not be assessed due to the absence of standardized measures (e.g., Clinical Frailty Scale or Fried criteria) in our retrospective dataset. Third, although postoperative pulmonary complications, including pneumonia, were observed, inconsistent documentation limited further analysis. These limitations have been acknowledged and underscore the need for prospective studies with standardized, comprehensive data collection to enable more detailed and accurate outcome evaluations.

Conclusions

In summary, the EuroSCORE II score of >8, blood Alb level of <25 g/L at admission and post-surgery, and post-surgery blood Cr level of >115 µmol/L are independent risk factors of long-term mortality in surgically treated aTAAD patients. Future efforts should be directed at improving the perioperative management of these patients to improve the outcomes.

Supplementary

The article’s supplementary files as

Ethical 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 study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. Given that the present study was a retrospective investigation utilizing existing data, obtaining ethics approval was not required, in line with the Fuwai Hospital’s guidelines for retrospective analyses involving anonymized data. Individual consent for this retrospective analysis was waived.

Data Sharing Statement

Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2024-2213/dss

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DOI: 10.21037/jtd-2024-2213