Congenitally corrected transposition: complex anatomic repair or Fontan pathway?

Clinical Factors Affecting Survival in Patients with Congenitally Corrected Transposition of the Great Arteries: A Systematic Review and Meta-Analysis

Background: Congenitally corrected transposition of the great arteries (cc-TGA) is a defect characterized by arterio-ventricular and atrioventricular disconcordance. Most patients have co-existing cardiac abnormalities that warrant further treatment. Some patients do not require surgical intervention, but most undergo physiological repair or anatomical surgery, which enables them to reach adulthood. Aims: We aimed to evaluate mortality risk factors in patients with cc-TGA. Results: We searched the PubMed database and included 10 retrospective cohort studies with at least a 5-year follow-up time with an end-point of cardiovascular death a minimum of 30 days after surgery. We enrolled 532 patients, and 83 met the end-point of cardiovascular death or equivalent event. As a risk factor for long-term mortality, we identified New York Heart Association (NYHA) class ≥III/heart failure hospitalization (OR = 10.53; 95% CI, 3.17-34.98) and systemic ventricle dysfunction (SVD; OR = 4.95; 95% CI, 2.55-9.64). We did not show history of supraventricular arrhythmia (OR = 2.78; 95% CI, 0.94-8.24), systemic valve regurgitation ≥moderate (SVR; OR = 4.02; 95% Cl, 0.84-19.18), and pacemaker implantation (OR = 1.48; 95% Cl, 0.12-18.82) to affect the long-term survival. In operated patients only, SVD (OR = 4.69; 95% CI, 2.06-10.71) and SVR (OR = 3.85; 95% CI, 1.5-9.85) showed a statistically significant impact on survival. Conclusions: The risk factors for long-term mortality for the entire cc-TGA population are NYHA class ≥III/heart failure hospitalization and systemic ventricle dysfunction. In operated patients, systemic ventricle dysfunction and at least moderate systemic valve regurgitation were found to affect survival.

Impact of the Rudimentary Chamber on Outcomes in Fontan Patients

Background: We sought to evaluate the influence of the rudimentary ventricle on long-term outcomes after the Fontan operation, focusing on exercise capacity and cardiac performance. Methods: Between 1995 and 2021, 290 patients underwent a total cavopulmonary connection. "Two-ventricle" Fontan circulation was defined as a rudimentary ventricle >30% of the dominant ventricle or >50% of its predicted normal value. This cohort was compared with patients with single-ventricle Fontan circulation. The primary endpoint was Fontan failure, and the secondary endpoints were VO2 and cardiac catheterization data at ten years postoperatively. Results: The median follow-up after the Fontan operation was 7.9 years (interquartile range: 1.9-13.9). No significant difference was found in Fontan failure-free survival between the "two-ventricle" Fontan circulation group and the single-ventricle Fontan circulation group (83/91, 93% vs 156/199, 78%), respectively at 20 years; P = .11). No significant difference was found in VO2 or cardiac performance except cardiac index, with 2.9 (2.3-4.8) versus 2.5 (2.3-4.3) L/min/m2 (P = .047). Fifty-one patients in the "two-ventricle" Fontan circulation group were followed up for over ten years after the Fontan operation. In the subgroup analysis of this cohort, the rudimentary ventricular end-diastolic volume/dominant ventricular end-diastolic volume ratio showed a significant positive correlation with dominant ventricular end-diastolic pressure (r = 0.58 [95% CI 0.35-0.74], P = .002) and a significant negative correlation with VO2 (r = -0.61 [95% CI -0.80 to -0.28], P = .001). Conclusions: The rudimentary ventricle was not significantly associated with any clinical disadvantages regarding Fontan failure. However, a large rudimentary ventricle was significantly associated with higher end-diastolic pressure and lower exercise capacity.

Outcomes After Anatomic Versus Physiologic Repair of Congenitally Corrected Transposition of the Great Arteries: A Systematic Review and Meta-Analysis

Surgical treatment for congenitally corrected transposition of the great arteries is widely debated, with both physiologic repair and anatomic repair holding advantages and disadvantages. This meta-analysis, which includes 44 total studies consisting of 1857 patients, compares mortality at different time points (operative, in-hospital, and post-discharge), reoperation rates, and postoperative ventricular dysfunction between these two categories of procedures. Although anatomic and physiologic repair had similar operative and in-hospital mortality, anatomic repair patients had significantly less post-discharge mortality (6.1% vs 9.7%; P = .006), lower reoperation rates (17.9% vs 20.6%; P < .001), and less postoperative ventricular dysfunction (16% vs 43%; P < .001). When anatomic repair patients were subdivided into those who had atrial and arterial switch versus those who had atrial switch with Rastelli, the double switch group had significantly lower in-hospital mortality (4.3% vs 7.6%; P = .026) and reoperation rates (15.6% vs 25.9%; P < .001). The results of this meta-analysis suggest a protective benefit of favoring anatomic repair over physiologic repair.

The presence of an additional ventricular chamber does not change the outcome of Fontan circulation: a comparative study

OBJECTIVES

The role of an additional ventricle in patients with a functional single ventricle undergoing the Fontan operation has been debated due to conflicting data. Our goal was to report our experience with Fontan circulation for complex congenital heart disease, with a focus on the influence that an additional ventricular chamber may have on early and long-term clinical outcomes.

METHODS

We performed a retrospective clinical study including all patients undergoing the Fontan procedure between 1978 and 2019. Clinical data were retrieved from our institutional database. A 'biventricular' Fontan (BVF) was defined as that performed in a patient with single ventricle anomaly where an additional diminutive ventricular cavity was present at echocardiographic evaluation.

RESULTS

A total of 210 consecutive patients with functional single ventricle were included. Among these, 46 had BVF (21.9%). Early complications occurred in 42 patients (20.0%; 11 in BVF vs 31 in univentricular Fontan; P = 0.53) There were 18 early deaths (8.6%) with no difference between the groups. At a median follow-up of 12.7 years (interquartile range 5.4-20.7), there were no significant differences in late mortality, whereas cardiac rhythm disturbances resulted more frequently in univentricular Fontan (P = 0.018). Statistical analysis showed an equal distribution of BVF across time (P = 0.620), and there were no significant differences in terms of early and late survival (P = 0.53 and P = 0.72, respectively) or morbidity (P = 0.45 and P = 0.80, respectively).

CONCLUSIONS

A secondary ventricle in Fontan circulation is not significantly related to any clinical disadvantage in terms of survival or onset of complications. However, the immediate postoperative course may be influenced negatively by the presence of an additional secondary ventricle.

Senning With Aortic Translocation and Anatomic Repair for Congenitally Corrected Transposition

BACKGROUND

Anatomic repair for congenitally corrected transposition of the great arteries with ventricular septal defect (VSD) and pulmonic stenosis has been accomplished with atrial switch and Rastelli. Aortic translocation offers a direct left ventricular outflow without an extraanatomic right ventricular-to-pulmonary conduit, which may lead to decreased reoperations. We reviewed our entire experience performing Senning with aortic translocation (SAT).

METHODS

From 2007 to 2017, 8 patients (mean age, 14.1 months; size, 8.86 kg) underwent SAT. Associated anomalies included situs inversus (n = 2), dextrocardia (n = 6), multiple muscular VSDs (n = 2), abnormal or straddling atrioventricular valve chords (n = 5), and branch pulmonary artery stenosis (n = 3). Four of 8 had previous systemic arterial shunts. Mean cardiopulmonary bypass was 487 minutes, and mean cardiac ischemic time was 307 minutes. Additional procedures included repair of branch pulmonary artery stenoses and closure of multiple muscular VSDs.

RESULTS

There was no hospital death. One patient was supported with extracorporeal membrane oxygenation because of junctional tachycardia on postoperative day 5. One patient required pacemaker placement for first-degree heart block. Median hospital length of stay was 31 days. Mean length of follow-up was 52 months. All patients remain well with mild or no aortic regurgitation. The first patient underwent a repeat surgical operation for pulmonary venous baffle obstruction 2 years after SAT.

CONCLUSIONS

Despite the technical complexity, patient outcomes have been satisfactory. We believe SAT provides a superior anatomic repair in these complex defects. Longer-term follow-up is needed regarding late intervention.

Biventricular Conversion in Unseptatable Hearts: "Ventricular Switch"

Patients with complex systemic and pulmonary venous anatomy, common atrioventricular canal defects and conotruncal anomalies have traditionally been routed to univentricular palliation and labeled as "unseptatable." This report describes our initial experience in septation/biventricular conversion ("ventricular switch"), utilizing the left ventricle (LV) as the subpulmonary ventricle, essentially recapitulating the physiology of congenitally corrected transposition of the great arteries. Five consecutive patients with challenging anatomic configuration underwent septation. All patients were severely cyanotic and had important functional limitations. All patients required complex atrial septation. Ventricular septation was precluded by fixed pulmonary vascular resistance in 2 patients. Systemic venous return was diverted to the morphologic LV as part of physiological 2V (n = 4) or 1.5 V repair (n = 1). Median conversion age was 9 years (range 11 months-46 years). Four patients had 12 previous cardiac surgical procedures in preparation for univentricular repair elsewhere. Three dimensional-printed heart models evaluated feasibility of septation. All patients are alive at a median follow-up of 0.6 years (range 0.08-2.7 years). Median hospital stay was 13 (range 10-60) days. LV recruitment improved functional status and significantly increased systemic oxygen saturation in all patients (79 ± 7% vs 95 ± 5%, P = 0.003). We report a novel paradigm for successfully utilizing both ventricles with the morphologic LV as the subpulmonary ventricle, in a complex population thought to be unseptatable. This approach is versatile and can likely be extrapolated to other complex anatomic configurations. Although we utilized this strategy in patients of variable age, earlier ventricular switch may yield the best results.

Systematic review and meta-analysis of outcomes of anatomic repair in congenitally corrected transposition of great arteries

BACKGROUND

Treatment of congenitally corrected transposition of great arteries (cc-TGA) with anatomic repair strategy has been considered superior due to restoration of the morphologic left ventricle in the systemic circulation. However, data on long term outcomes are limited to single center reports and include small sample sizes.

AIM

To perform a systematic review and meta-analysis for observational studies reporting outcomes on anatomic repair for cc-TGA.

METHODS

MEDLINE and Scopus databases were queried using predefined criteria for reports published till December 31, 2017. Studies reporting anatomic repair of minimum 5 cc-TGA patients with at least a 2 year follow up were included. Meta-analysis was performed using Comprehensive meta-analysis v3.0 software.

RESULTS

Eight hundred and ninety-five patients underwent anatomic repair with a pooled follow-up of 5457.2 patient-years (PY). Pooled estimate for operative mortality was 8.3% [95% confidence interval (CI): 6.0%-11.4%]. 0.2% (CI: 0.1%-0.4%) patients required mechanical circulatory support postoperatively and 1.7% (CI: 1.1%-2.4%) developed post-operative atrioventricular block requiring a pacemaker. Patients surviving initial surgery had a transplant free survival of 92.5% (CI: 89.5%-95.4%) per 100 PY and a low rate of need for pacemaker (0.3/100 PY; CI: 0.1-0.4). 84.7% patients (CI: 79.6%-89.9%) were found to be in New York Heart Association (NYHA) functional class I or II after 100 PY follow up. Total re-intervention rate was 5.3 per 100 PY (CI: 3.8-6.8).

CONCLUSION

Operative mortality with anatomic repair strategy for cc-TGA is high. Despite that, transplant free survival after anatomic repair for cc-TGA patients is highly favorable. Majority of patients maintain NYHA I/II functional class. However, monitoring for burden of re-interventions specific for operation type is very essential.

Two Ventricles Are Not Better Than One in the Fontan Circulation: Equivalent Late Outcomes

BACKGROUND

A subset of patients who underwent Fontan operations has two adequate-sized ventricles, but an anatomic biventricular circulation cannot be achieved because of complex morphology or for technical reasons. This study sought to determine whether these patients with two-ventricle Fontan circulation had superior outcomes compared with those with a single ventricle.

METHODS

A binational Fontan Registry of patients (n = 1,377) was analyzed to identify those patients with two adequate ventricles. This cohort was compared with patients with single-ventricle Fontan circulation. The primary end point was a composite end point called "Fontan failure" encompassing death, heart transplantation, Fontan takedown or conversion, protein-losing enteropathy, plastic bronchitis, or New York Heart Association functional class III or IV.

RESULTS

A total of 79 Fontan patients with two adequate ventricles (2V) were compared with 1,291 single ventricle (1V) Fontan patients. Median follow-up for the entire cohort was 11.5 years (interquartile range, 5.1 to 18.8 years). There was no difference in unadjusted 15-year freedom from Fontan failure (2V: 81% [95% confidence interval (CI), 69% to 94%] vs 1V: 86% [95% CI, 83% to 88%], p = 0.4). Propensity-score matching for potential confounding factors yielded 75 two-ventricle Fontan patients matched with 604 single-ventricle Fontan patients, in which 15-year freedom from Fontan failure was also not different (2V: 79% [95% CI, 67% to 94%] vs 1V: 87% [95% CI, 84% to 91%], p = 0.3).

CONCLUSIONS

The two-ventricle Fontan circulation does not have better outcomes compared with the single-ventricle Fontan circulation. Late outcomes may depend more on other characteristics of the Fontan circulation. This finding is relevant when the Fontan procedure is being considered as an alternative to anatomic repair in patients with complex two-ventricle morphologies.