Abstract
OBJECTIVES
Controversy exists in ascertaining the ideal location for adults with congenital heart disease requiring surgical intervention. In this study, we sought to compare the perioperative management between our paediatric and adult hospitals and to determine how clinical factors and the location affect the length of stay after pulmonary valve replacement.
METHODS
A retrospective analysis of patients, 18 years of age, undergoing pulmonary valve replacement was conducted at our paediatric and adult hospitals between 1 January 2000 and 30 October 2014. Patients with previous Ross or concomitant left heart procedures were excluded. Descriptive statistics were used to assess demographics and clinical characteristics. Inverse probability weight-adjusted models were used to determine differences in the number of surgical complications, duration of mechanical ventilation and postoperative length of stay between paediatric and adult hospitals. Additional models were calculated to identify factors associated with prolonged length of stay.
RESULTS
There were altogether 98 patients in the adult (48 patients) and paediatric (50 patients) hospitals. Patients in the adult hospital were older with more comorbidities (arrhythmia, hypertension, depression and a history of cardiac arrest, all P < 0.05). Those at the paediatric hospital had better preoperative right ventricular function and less tricuspid regurgitation. The cardiopulmonary bypass time, the length of intubation and the length of stay were higher at the adult hospital, despite no difference in the number of complications between locations. Factors contributing to the increased length of stay include patient characteristics and postoperative management strategies. There were no deaths.
CONCLUSIONS
Pulmonary valve replacement may be performed safely with no deaths and with a comparable complication rate at both hospitals. Patients undergoing surgery at the adult hospital have longer intubation times and length of stay. Opportunities exist to streamline management strategies.
Keywords: Congenital heart disease, Adult congenital heart disease, Outcomes
INTRODUCTION
A significant number of patients with congenital heart disease (CHD) require congenital heart surgery in adulthood. It is estimated that approximately 50% of patients with tetralogy of Fallot undergo reoperation within 30 years [1]. Pulmonary valve replacement (PVR) is one of the most common congenital heart procedures performed in adults with CHD [2, 3].
Despite the growing number of adults who require congenital heart surgery, the optimal hospital setting in which these patients should be cared for is not known. The surgeon and hospital characteristics have been examined for a variety of adult congenital heart surgical procedures in prior studies [4–10]. However, no studies to date have had sufficient data to evaluate whether the variation in outcome was due to differences in the background training of operating surgeons (adult versus congenital) or practice differences between hospitals (adult versus paediatric). The relative benefit of one setting over another remains challenging to define in part due to the lack of a widely accepted risk adjustment tool for case mix and variable perioperative management techniques among institutions. Medical comorbidities in adult CHD (ACHD) patients can add to surgical risk, which makes ascertainment of the ideal location of care that much more difficult.
Our ACHD centre spans both a paediatric hospital and an adult hospital and, as such, provides a unique opportunity to examine surgical outcomes. As a joint medical-surgical programme, patients are assigned to either hospital for surgery by a cardiologist and cardiac surgeon based on patient age, comorbidities and patient preference. In general, older patients with medical comorbidities undergo surgery in the adult hospital; whereas younger, less medically complex patients undergo surgery in the paediatric hospital. To better understand the influence of the hospital setting on perioperative outcomes for ACHD surgery, we examine our programmatic practice of assigning patients to the paediatric or adult hospitals for PVR surgery.
Specifically, the aims of this study are to (i) describe differences in patient mix, operative practice and perioperative management between our paediatric and adult hospitals; (ii) determine whether perioperative outcomes differed between the 2 hospitals and (iii) perform an exploratory analysis to evaluate patient-level, operative and perioperative practice factors affecting length of stay (LOS) after PVR.
MATERIALS AND METHODS
Study population and data sources
A single-centre retrospective cohort study was performed. Patients ≥18 years who underwent PVR from 2000 to 2014 at either the Children’s Hospital of Philadelphia (CHOP) or the Hospital of the University of Pennsylvania (HUP) were studied. Exclusion criteria were previous Ross operation or concomitant left-sided heart surgery. Data were obtained from the Society of Thoracic Surgeons Congenital Heart Surgery Database (STS-CHSD) at CHOP and from the Society of Thoracic Surgeons Adult Cardiac Surgery Database at HUP. Additional data elements were abstracted from a review of the electronic medical records at both hospitals.
Study measures and statistical analysis
The primary outcomes of interest were surgical complications, duration of mechanical ventilation and postoperative LOS. Complications were categorized according to the STS-CHSD Version 3.22 and the standardized definitions [11]. Compiled by an international multidisciplinary working group, this catalogue defined a complication as an unwanted clinical event and defined a set of ICD-9-CM (International Statistical Classification of Diseases and Related Health Problems 9th Revision - Clinical Modification) codes as a means to identify complications during congenital heart surgery admissions [12, 13]. Complications occurring (i) within 30 days after surgery in or out of the hospital or (ii) after 30 days during the same hospitalization subsequent to the surgery were included. All complications were adjudicated with an STS Data Specialist at CHOP and an attending congenital heart surgeon (S.F.).
The primary exposure of interest was the location of surgery (paediatric or adult hospitals). As previously described, we typically refer older patients with a greater number of comorbid conditions to our adult hospital. This practice potentially alters covariates for outcome, creating the possibility of confounding by indication. In addition, during the study period, 5 surgeons operated at the 2 institutions. The operating surgeon (congenital versus adult) was an additional variable included in all models based on a priori suspicion that it was an important covariate to include. Descriptive statistics for subjects at our adult and paediatric hospitals were calculated. Differences in the distributions of these characteristics between the 2 subgroups were compared using the χ2 test, the Fisher’s exact test and the Mann–Whitney U-test.
To overcome the aforementioned confounding by indication, we generated stabilized inverse probability weights (IPWs), which were then applied to our multivariable regression outcome models. This approach adjusts for differences in the distribution of important covariates between the 2 patient populations [14]. These weights were derived from a multivariable logistic regression model [15]. The components of the propensity score model were chosen based on both clinical suspicion and descriptive statistics described above with care to avoid including multiple collinear variables as previously described [16–18]. Variables were age at the time of surgery, gender, body mass index 30, arrhythmia, hypertension, depression, genetic syndrome, number of prior median sternotomies, pulmonary regurgitation as surgical indication, preoperative left ventricular dysfunction and preoperative right ventricular (RV) dysfunction.
To determine whether each covariate included in the propensity score model was adequately balanced across the 2 hospitals, individual weighted regression models were examined to determine if surgery location is still significantly associated with each subject-level characteristic after the weight was applied. A non-statistically significant association indicates that in the weighted sample there is no longer an association between the surgery location and the subject-level characteristic. Any covariate not successfully balanced was included as a covariate in the outcome models.
These IPWs were then applied to multivariable models to evaluate whether outcomes differed between adult and paediatric hospitals after an adjustment for measured confounders. Specifically, multivariable IPW Poisson regression models were performed for each of the primary outcomes. The incidence rate ratio with 95% confidence intervals is presented.
A set of exploratory secondary analyses was performed to evaluate as to which patient characteristics and perioperative practices were associated with LOS. A separate univariable Poisson regression model was used to test the association between each covariate and LOS.
An alpha of 0.05 was used as the threshold for statistical significance and all statistical tests are 2-sided tests. SAS (version 9.4) and STATA (version 15) were used to conduct all analyses.
RESULTS
In total, 98 patients underwent PVR, with 50 patients at the paediatric hospital and 48 patients at the adult hospital (Table 1). The median age for the cohort was 31.3 years (range 18.3–65.2) with significantly younger patients undergoing surgery at the paediatric hospital [25.1 years (range 18.3–48.7)] compared to the adult hospital [37.1 years (range 20.4–65.2)], P-value <0.001. In general, patients operated on in the adult hospital had more medical comorbidities such as arrhythmia, hypertension, obesity, depression and renal insufficiency.
Table 1:
Preoperative demographic, clinical characteristics and imaging parameters, n = 98
| Total (n = 98) | Paediatric (n = 50) | Adult (n = 48) | P-value | |
|---|---|---|---|---|
| Age (years), median (range) | 31.3 (18.3–65.2) | 25.1 (18.3–48.7) | 37.1 (20.4–65.2) | <0.001 |
| Weight (kg), median (range) | 67.2 (39.8–160.9) | 67.6 (39.8–109) | 66.6 (44.1–160.9) | 0.24 |
| Female, n (%) | 41 (42) | 19 (38) | 22 (24) | 0.43 |
| Race (n=94), n (%) | ||||
| White | 77 (79) | 43 (86) | 34 (71) | 0.067 |
| Black | 9 (9) | 4 (8) | 5 (10) | 0.74 |
| Other | 8 (8) | 2 (4) | 6 (13) | 0.16 |
| Comorbidity, n (%) | ||||
| Arrhythmia | 50 (51) | 19 (38) | 31 (65) | 0.008 |
| Obesity | 15 (15) | 4 (8) | 11 (23) | 0.051 |
| Hypertension | 11 (11) | 1 (2) | 10 (21) | <0.003 |
| Depression | 10 (10) | 2 (4) | 8 (17) | 0.049 |
| Renal insufficiency | 4 (4) | 0 | 4 (8) | 0.054 |
| Cardiac arrest | 5 (5) | 0 | 5 (10) | 0.025 |
| Hyperlipidaemia | 4 (4) | 1 (2) | 4 (8) | 0.20 |
| Chronic liver disease | 4 (4) | 2 (4) | 2 (4) | 1.00 |
| Chronic lung disease | 6 (6) | 3 (6) | 3 (6) | 1.00 |
| Stroke | 7 (7) | 3 (6) | 4 (8) | 0.71 |
| Cardiac medications, n (%) | 52 (53) | 25 (50) | 27 (56) | 0.54 |
| Genetic syndrome (n=97), n (%) | ||||
| DiGeorge | 8 (8) | 5 (10) | 3 (6) | 0.72 |
| Down | 2 (2) | 2 (4) | 0 | 0.50 |
| Other | 1 (1) | 0 | 1 (2) | 0.49 |
| Congenital heart lesion, n (%) | ||||
| Tetralogy of Fallot | 75 (77) | 42 (84) | 33 (69) | 0.075 |
| Pulmonary stenosis | 22 (22) | 8 (16) | 14 (29) | 0.12 |
| Other | 1 (1) | 0 | 1 (2) | 0.49 |
| Surgical indication, n (%) | ||||
| Pulmonary regurgitation | 75 (77) | 41 (82) | 34 (71) | 0.19 |
| Pulmonary stenosis | 4 (4) | 1 (2) | 3 (6) | 0.36 |
| Mixed pulmonary valve | 15 (15) | 8 (16) | 7 (15) | 0.85 |
| Other | 4 (4) | 0 | 4 (8) | 0.054 |
| Previous median sternotomy, median (range) | 1 (0–4) | 1 (0–4) | 1 (0–4) | 1.00 |
| LV dysfunction, at least mild,an (%) | 15/89 (17) | 3/43 (7) | 12/46 (26) | 0.016 |
| RV dysfunction, at least mild,an (%) | 48/90 (53) | 13/42 (31) | 35/48 (73) | <0.001 |
| Pulmonary regurgitation, at least moderate,an (%) | 90/92 (98) | 46/46 (100) | 44/46 (96) | 0.50 |
| Pulmonary stenosis, at least moderate,an (%) | 11/59 (19) | 5/36 (14) | 6/23 (26) | 0.24 |
| Tricuspid regurgitation, at least moderate,an (%) | 29/97 (30) | 9/49 (18) | 20/48 (42) | 0.012 |
| RV end-diastolic volume (ml/m2), median (range)b | 170.3 (104–402) | 168.5 (107–208) | 174 (104–204) | 0.28 |
| RV end-systolic volume (ml/m2), median (range)b | 96 (47–318) | 82.9 (47–130) | 105 (48–318) | <0.003 |
| RV ejection fraction (%), median (range)b | 43 (15–65) | 49 (35–65) | 38 (15–63) | <0.001 |
| LV ejection fraction (%), median (range)b | 59 (32–81) | 64 (48–81) | 55 (32–76) | <0.003 |
Echocardiography.
Cardiac magnetic resonance imaging.
LV: left ventricular; RV: right ventricular.
Key imaging parameters of preoperative ventricular size, function and valvar regurgitation are summarized in Table 1. Patients at the adult hospital, on average, had worse biventricular function and tricuspid regurgitation compared to those who underwent PVR in the paediatric hospital. However, the prevalence of at least moderate pulmonary regurgitation was comparable. Only 74 patients, 39 (81%) at the adult hospital and 35 (70%) at the paediatric hospital, had preoperative cardiac magnetic resonance imaging. There was no difference in the indexed RV end-diastolic volume but indexed RV end-systolic volume was higher in those who underwent surgery at the adult hospital.
All PVR surgeries at the paediatric’s hospital and the majority (69%) of those at the adult hospital were performed by a congenital heart surgeon. Most patients (79%) underwent concurrent procedures including pulmonary arterioplasty, tricuspid valvuloplasty, RV outflow tract procedure and RV resection or plication. The prevalence of concomitant procedures was not significantly different between hospitals. Cardiopulmonary bypass time was shorter and postoperative echocardiogram before discharge was more frequently performed in the paediatric hospital; whereas practices such as intraoperative transoesophageal echocardiography, central line placement and vasoactive medication administration were more frequent in the adult hospital (Fig. 1).
Figure 1:
Operative and perioperative characteristics, n = 98. CHS: congential heart surgeon; CPB: cardiopulmonary bypass; TOE: transoesophageal echocardiogram; TTE: transthoracic echocardiogram; XC: cross-clamp.
Outcomes
There were significant unadjusted differences in outcomes between the adult and paediatric hospitals (Table 2). Specifically, intubation time and total length of stay were shorter in the paediatric hospital but the frequency of having incurred ‘any complication’ (at least 1 complication per patient) was no different between hospitals. There were 26 complications sustained by 15 patients at the paediatric hospital compared to 17 complications in 9 patients in the adult hospital. The median range of number of complications per patient was zero (range 0–6) at both hospitals. In general, the most frequent complications were unplanned readmission to hospital within 30 days of surgery in 7.1% (7/98), arrhythmia requiring drug therapy in 6.1% (6/98), arrhythmia requiring cardioversion or defibrillation in 5.1% (5/98), arrhythmia requiring temporary pacing in 4.1% (4/98) and postoperative respiratory insufficiency requiring reintubation in 4.1% (4/98). There were no significant differences in the length of stay in the intensive care unit (ICU). More patients were discharged to home without physical therapy from the paediatric hospital but this did not reach statistical significance. There was no death at either hospital.
Table 2:
Unadjusted outcomes after pulmonary valve replacement surgery in paediatric versus adult hospitals
| Total (n = 98) | Paediatric (n = 50) | Adult (n = 48) | P-value | |
|---|---|---|---|---|
| Length of intubation (h), median (range) | 9.4 (3.7–1031.2) | 4.9 (3.7–58) | 13.8 (5.0–1031.2) | <0.001 |
| ICU length of stay (h), median (range) | 28.4 (14.8–1050) | 30.8 (17.4–234.8) | 27.9 (14.8–1050) | 0.41 |
| Any complication, n (%) | 24 (24) | 15 (30) | 9 (19) | 0.20 |
| Total length of stay (days), median (range) | 5 (2–60) | 3 (2–14) | 6 (3–60) | <0.001 |
| Discharged home, n (%) | 91 (93) | 49 (98) | 42 (88) | 0.062 |
ICU: intensive care unit.
Table 3 shows the results of the unadjusted and adjusted multivariable IPW regression models examining the primary outcomes of total length of stay, duration of mechanical ventilation and number of complications. After adjustment for measured confounders, PVR at the adult hospital was associated with a 33% higher predicted LOS (P = 0.034) and nearly 3-fold longer intubation time (P = 0.007). There was no significant difference in the number of postoperative complications seen between the 2 hospitals.
Table 3:
Multivariable unweighted and adjusted Poisson models for outcome (paediatric hospital sample as reference)
| Unweighted IRR (95% CI) | P-value | Adjusted IRR (95% CI) | P-value | |
|---|---|---|---|---|
| Length of intubation (h) | 4.56 (3.05–6.81) | <0.01 | 2.94 (1.36–6.35) | 0.007 |
| Number of complications | 0.68 (0.37–1.26) | 0.22 | 0.45 (0.16–1.23) | 0.12 |
| Total length stay (days) | 1.90 (1.60–2.20) | <0.01 | 1.33 (1.02–1.73) | 0.034 |
Adjusted models are both covariate-adjusted and inverse probability weighted.
CI: confidence interval; IRR: incidence rate ratio.
The association between patient-level, operative and perioperative factors and increased LOS was assessed across the entire study population (Table 4). Medical comorbidities (especially depression), cardiac medications, biventricular dysfunction, at least moderate pulmonary regurgitation and mild tricuspid regurgitation were associated with longer length of stay. Perioperative factors such as intubation for greater than 24 h, central line placement, and vasoactive medication use were also associated with longer length of stay after PVR. Being operated on by an adult cardiac surgeon was associated with an over 2-fold increased risk of longer length of stay compared to those operated on by a congenital heart surgeon (P < 0.001).
Table 4:
Univariable Poisson models for length of stay
| IRR (95% CI) | P-value | |
|---|---|---|
| Clinical characteristics | ||
| Arrhythmia | 1.46 (1.24–1.71) | <0.001 |
| Depression | 2.73 (2.27–3.28) | <0.001 |
| Number of comorbidities | 1.24 (1.18–1.29) | <0.001 |
| Genetic syndrome | 1.04 (0.82–1.31) | 0.76 |
| Number of cardiac medications | 1.24 (1.17–1.32) | <0.001 |
| Imaging parameters | ||
| LV dysfunction, at least mild | 1.36 (1.11–1.65) | 0.002 |
| RV dysfunction, at least mild | 1.86 (1.55–2.15) | <0.001 |
| PR, at least moderate | 0.62 (0.49–0.79) | <0.001 |
| PS, at least moderate | 1.28 (1.02–1.60) | 0.033 |
| TR, at least mild | 1.64 (1.40–1.92) | <0.001 |
| RVEDV ≥150 ml/m2 | 0.95 (0.75–1.20) | 0.67 |
| RVESV ≥80 ml/m2 | 1.33 (1.08–1.65) | 0.009 |
| Operative and perioperative | ||
| Non-congenital heart surgeon | 2.24 (1.90–2.64) | <0.001 |
| Any concurrent procedure | 1.52 (1.22–1.89) | <0.001 |
| Central line access | 1.81 (1.52–2.16) | <0.001 |
| Intraoperative blood transfusion | 1.78 (1.52–2.09) | <0.001 |
| Vasoactive medication use | 1.80 (1.50–2.15) | <0.001 |
| Intubation ≥24 h | 2.72 (2.30–3.22) | <0.001 |
CI: confidence interval; IRR: incidence rate ratio; LV: left ventricular; PR: pulmonary regurgitation; PS: pulmonary stenosis; RV: right ventricular; RVEDV: right ventricular end diastolic volume; RVESV: right ventricular end systolic volume; TR: tricupsid regurgitation.
DISCUSSION
The ideal hospital setting for ACHD surgery remains controversial. Adult hospitals are well-equipped to care for adults and their comorbid conditions, whereas paediatric facilities are favoured because of the familiarity with CHD. In 2010, Karamlou et al. [5] assessed care paradigms examining the congenital heart surgeon versus the adult surgeon and the paediatric hospital versus the adult hospital. They concluded that patients are best served when treated by congenital heart surgeons in a paediatric hospital, and attributed this to refined processes of care in addition to the expertise of the surgeons themselves. However, they also acknowledged that patients operated on at the adult hospital can be more complex and note that ACHD patients who are operated on by congenital heart surgeons in the adult hospital had the worst surgical outcomes. Though the study authors suggest that ACHD patients should be operated on by congenital heart surgeons in a centre mimicking the paediatric hospital, it remains unclear as to which features of a paediatric hospital confer these advantages and whether some of the benefits of the paediatric hospital are attributable to younger patients with less comorbidities.
Kogon et al. [7] offered the opposite conclusion regarding the setting of care. In this single-centre study of 303 ACHD operations performed by congenital heart surgeons in either a paediatric or adult hospital, risk factors for surgical mortality included older age and surgery performed at a paediatric hospital. The authors conclude that these patients are best served by a congenital heart surgeon operating in an adult hospital setting. Both studies look to answer the question of the ideal location of care but with the lack of adjustment for case mix and comorbidities, it is difficult to know how and to what extent these factors impact outcomes.
Of the self-recognized ACHD centres in the US, many are based at joint adult and paediatric hospitals on the same campus, whereas other centres function from either exclusively an adult hospital or a paediatric hospital. Our ACHD programme spans both a free-standing paediatric hospital and adult hospital and is uniquely positioned to examine the hospital setting on surgical outcomes. To account for case mix, we concentrated on 1 surgical procedure (PVR) and analysed concomitant surgical procedures to further ensure that we adequately captured variations in surgical complexity. Our clinical practice for choosing the surgical location is based on the clinical assessment and the joint decision by the ACHD cardiologist and the cardiac surgeon and generally based on age, comorbidities and patient preference. This is largely driven by the access to adult subspecialty services to address comorbidities and potential perioperative complications that are not available at the paediatric hospital. By developing a propensity score to balance the groups as much as possible to account for differences in patient characteristics, we developed models accounting for surgeon type that could then examine the hospital setting as the exposure of interest on surgical outcomes.
It is well recognized that PVR is performed safely with low mortality and minimal morbidity at both paediatric and adult hospitals, which is validated in our study. Because hospital mortality for ACHD procedures is low, LOS, hospital costs or complications may be more appropriate outcome metrics [8].
We hypothesized that there may be potentially modifiable practices that could impact outcomes such as LOS. In our exploratory analysis, we found that central line placement, vasoactive medication use and intubation for greater than 24 h were predictors of longer LOS. These are used almost universally in the adult hospital and sparingly in the paediatric hospital. We cannot measure the degree to which these differences reflect institutional practice or are therapeutic responses to individual patients. However, the uniformity of practice at the adult hospital suggests that some of it may be due to routine, standardized practice.
One practice difference between our paediatric and adult hospitals that could explain longer intubation times is the utilization of fast-track extubation. There exists an established relationship between longer intubation and increased LOS, and adverse outcomes [19]. Early extubation has been associated with decreased infectious complications, renal failure, stroke, ICU readmission, reintubation, operative mortality and cost [20]. Owing to the younger and generally healthier state of paediatric patients, operating room extubation is routine for many paediatric cardiac surgical interventions [21]. And, likely because of the inherently older and sicker adult population, there is a historic delay towards extubation at our adult hospital. Given the relatively young age of our ACHD patients with less comorbid conditions, our results suggest an anaesthetic approach and perioperative care may be modified to permit operating room extubation with more frequency [22, 23].
The same can be stated for insertion of central lines and administration of inotropes in the perioperative period. Neither are performed with high frequency in our paediatric hospital but are routine practice in our adult hospital. Specifically, central venous access is standard practice for redo sternotomy at our adult hospital and is hospital policy for the administration of inotropy if/when needed. It is possible that the presence of a central line may lower the threshold for utilization of such medications in the perioperative period and impact LOS. A goal-directed therapy, with the aid of pulmonary arterial catheter and central venous access, has been extensively examined in the adult cardiac surgery population and forms the basis of some of these practices. Taking into consideration younger age, less complex case mix and lower prevalence of multiorgan dysfunction in the ACHD patient, it may be possible that some of these practices could be reserved only for ACHD patients deemed at especially high surgical risk.
There were also patient-level factors associated with increased LOS that may be potentially modifiable. Depression was associated with an over 2.7-fold higher predicted length of stay and was the characteristic with the highest incidence rate ratio of all the variables tested. Depression has been identified as a risk factor for high resource use in ACHD surgery and though its relationship with surgical outcomes is not well-understood, screening and treatment of depression may render it a modifiable risk factor [24, 25]. Biventricular dysfunction and a parameter of RV size (end-systolic dimension by cardiac magnetic resonance imaging) was also found to be associated with longer hospitalization after PVR. Though our analysis was not robust enough to fully understand the nature of this association, it is possible that these parameters reflect pulmonary valve disease advanced enough to cause a significant impact on the ventricular size and function and severity of tricuspid regurgitation. We cautiously suggest that our data could support an earlier referral for PVR to mitigate prolonged LOS.
By attempting to separate the congenital versus non-congenital heart surgeon from the hospital setting (adult versus paediatrics), we aim to highlight the contribution of surgical expertise at the hand of an operator versus institutional expertise. Our findings support conclusions from other studies emphasizing the importance of a congenital heart surgeon familiar with the anatomy and physiology of CHD in the care of the ACHD surgical patient [4, 5, 7].
Limitations
The study is a retrospective cohort study of our institutional experience with some inherent limitations. There is an obvious selection bias, as clinically we sort patients from 1 hospital to another based on patient characteristics. Though our statistical approach sought to adjust for these relevant confounders, unmeasured confounding remains a possibility. In addition, IPW modelling is expedient from the perspective of statistical power, but with a fixed study population we acknowledge the risk of type II error. It must be acknowledged that the study is not able to adequately describe the relative contributions of surgeon background (congenital versus non-congenital) and hospital setting to outcomes, one reason being the lack of non-congenital heart surgeons performing PVR at the paediatric hospital. The relatively small numbers in this cohort is another limitation in identifying associations that are not powered for detection.
CONCLUSION
In conclusion, in our dual-hospital ACHD programme, patients who underwent PVR at the adult hospital were older, had more medical comorbidities and a higher prevalence of biventricular dysfunction compared to those at the paediatric hospital. After adjusting for patient-level variables that could confound patient sorting of location, LOS and duration of mechanical ventilation remained higher in the adult hospital, but there was no significant difference in the number of surgical complications. Predictors of longer LOS included central line placement, intubation time greater than 24 h and administration of vasoactive medications. The PVR surgery performed by a non-congenital heart surgeon was associated with a 2-fold increase risk of longer length of stay.
Although PVR may be performed safely in either a paediatric or adult venue, models of care are highly dependent on the local practice and patient population. In a dual-hospital setting, expertise and best practice patterns from each institution may be shared to allow for improved outcomes. Further investigations in institutional perioperative practices that could improve surgical outcomes in ACHD are warranted.
Funding
This work was supported in part by a generous contribution from the Bronchick Family Foundation, the HFO Foundation and Big Hearts to Little Hearts.
Conflict of interest: none declared.
Footnotes
Presented at the 32nd Annual Meeting of the European Association for Cardio-Thoracic Surgery, Milan, Italy, 18–20 October 2018.
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