Biventricular hearts not amenable to biventricular 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.

Where are we after 50 years of the Fontan operation?

First introduced in 1971, the Fontan procedure is the final common destination for all patients with a functional single ventricle. The procedure itself has evolved tremendously over the last five decades. This review traces this journey and presents the importance, outcomes and future outlook of the procedure in the current era.

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.

Staged Biventricular Repair-Oriented Strategy in Borderline Biventricular Repair Candidates with Ventricular Septal Defect

Although borderline biventricular repair (BVR) candidates unsuitable for primary BVR are often subjected to single-ventricle repair (SVR), some of them reach BVR by staged strategy. We evaluated our staged BVR-oriented strategy in borderline BVR candidates with ventricular septal defect (VSD) in whom a BVR/SVR decision was deferred beyond the neonatal period. Forty-two patients were treated with the approach between 1991 and 2012. They had been followed toward BVR until it was judged impossible. Outcomes, time course toward definitive repair (DR: BVR, SVR, or 1 + 1/2 ventricle repair), and hemodynamics were reviewed. A total of 57 palliative surgeries were performed before BVR or bidirectional Glenn (BDG), namely procedures to control pulmonary blood flow in 40, to improve mixing in 5, and to promote left ventricle (LV) growth in 5. LV growth was achieved in four patients. There were three cardiac deaths. Except for four awaiting patients, 19 reached BVR (50 %), 11 patients were converted to other than BVR, and 28 patients achieved DR (74 %) at the median age of 30.9 months. Cardiac cath before BVR or BDG performed at the median age of 22.5 months revealed well-preserved pulmonary vasculature with the median pulmonary artery pressure of 14 mmHg, except three patients unsuitable for SVR. In conclusion, our staged BVR-oriented strategy required longer time course and more complex palliative surgeries compared with a simple SVR strategy. Leaving open the possibility of a late crossover to an SVR pathway is mandatory when adopting staged BVR-oriented strategy in these complex patients.

The new concept of univentricular heart

The concept of univentricular heart moved from hearts with only one ventricle connected with atria [double inlet ventricle or absent atrioventricular (AV) connection] to hearts not amenable to biventricular repair, namely hearts with two ventricles unable to sustain separately pulmonary and systemic circulations in sequence. In the latter definition, even hearts with one hypoplastic ventricle are considered "functional" univentricular hearts. They include pulmonary/aortic atresia or severe stenosis with hypoplastic ventricle, and rare conditions like huge intramural cardiac tumors and Ebstein anomaly with extreme atrialization of right ventricular cavity. In this setting, the surgical repair is univentricular with "Fontan" operation, bypassing the ventricular mass. In other words, functionally univentricular heart is a condition in which, after surgery, only one ventricle sustain systemic circulation. Univentricular hearts (double inlet or absent AV connection) almost invariably show two ventricular chambers, one main and one accessory, which lacks an inlet portion. The latter is located posteriorly when morphologically left and anteriorly when morphologically right. As far as double inlet left ventricle, this is usually associated with discordant ventriculo-arterial (VA) connection (transposition of the great arteries) and all the blood flow to the aorta, which takes origin from the hypoplastic anterior right ventricle, is ventricular septal defect (bulbo-ventricular foramen) dependent. If restrictive, an aortic arch obstruction may be present. Double inlet left ventricle may be rarely associated with VA concordance (Holmes heart). As far as double inlet right ventricle with posterior hypoplastic left ventricular cavity, ventriculo-arterial connection is usually of double outlet type; thus the term double inlet-outlet right ventricle may be coined. Absent right or left AV connection may develop in the setting of both d- or l-loop, whatever the situs. In this condition, the contra-lateral patent AV valve may be either mitral or tricuspid in terms of morphology and the underlying ventricle (main chamber) either morphologically left or right. Establishing the loop, whatever right or left (also called right or left ventricular topology), is a fundamental step in the segmental-sequential analysis of congenital heart disease.

Anatomical repair of double outlet right ventricle associated with complete atrioventricular septal defect and pulmonary stenosis: extending the indications for aortic translocation

The combination of double outlet right ventricle (DORV) and complete atrioventricular septal defect (CAVSD) remains a surgical challenge for anatomical repair. Inasmuch as the ventricular septal defect is noncommitted in this combination, the major concern regarding anatomical repair is the reconstruction of the unobstructed left ventricular outflow tract without compromising right ventricular volume and the right ventricular outflow tract. We report on a patient who underwent an anatomical repair using aortic root translocation for DORV with CAVSD and pulmonary stenosis (PS).

Biventricular repair in patients with heterotaxy syndrome

OBJECTIVE

Complex intracardiac and extracardiac anatomy is often confronted during biventricular repair in patients with heterotaxy syndrome. We examined factors affecting surgical outcomes in these patients.

METHODS

Between January 1990 and July 2007, 371 patients received a diagnosis of heterotaxy syndrome; 91 (91/371, 24.5%) underwent biventricular repair. Left atrial isomerism was present in 73% (66/91) and right atrial isomerism in 10% (9/91), with indeterminate atrial anatomy in 17% (16/91). Median age at biventricular repair was 6.8 months (5 days to 22.3 years). Systemic venous anomalies were present in 75 patients, pulmonary venous anomalies in 26, and endocardial cushion defects in 36. Transposition complexes were present in 15 patients with atrioventricular discordance in 10; 8 underwent double switch, 2 received a physiologic repair, 2 underwent arterial switch, and 3 underwent the Rastelli operation. Other conotruncal anomalies included double-outlet right ventricle in 10 patients, tetralogy of Fallot in 3, and hemitruncus in 2. Separation of systemic from pulmonary venous return included intra-atrial baffling in 48 patients and extracardiac grafting in 2. Combined lesions were common, occurring in 99% (90/91). Statistical analysis with Kaplan-Meier and Cox proportional hazards models were performed.

RESULTS

Average follow-up was 44.9 +/- 57.5 months (3 days to 189.3 months). Kaplan-Meier estimated survival was 93.4% at 10 years; unbalanced complete atrioventricular canal was the only risk factor for mortality (P = .006). Subsequent procedures were common with a 10-year freedom from reoperation or reintervention of 38% +/- 7.5%. Arrhythmias occurred in 36 (39.6%) patients; bradyarrhythmia in 27 (29.7%) and tachyarrhythmia in 15 (16.5%). Freedom from any arrhythmia was 53.9% +/- 6.7% at 10 years.

CONCLUSIONS

Excellent survival for patients with heterotaxy undergoing biventricular repair can be expected, even for multiple, complex lesions. Reintervention is common, and arrhythmia is a long-term concern. This experience shows that patients with heterotaxy syndrome and complex cardiac anatomy can be considered for biventricular repair. Patients with unbalanced complete atrioventricular canal are a high-risk group for which selection criteria are particularly important.

Biventricular repair for right atrial isomerism

BACKGROUND

Biventricular repair is often difficult to accomplish in patients with right atrial isomerism because of complex anomalous structures.

METHODS

Ten patients with right atrial isomerism underwent biventricular repair. Their ages ranged from 15 months to 21 years. The follow-up period ranged from 1 month to 21 years. The Fontan procedure was unsuitable in 7 patients. The atrioventricular valves were separated in 5 patients and common in 5. One patient who had severe right-sided atrioventricular valvular regurgitation required concomitant prosthetic valve replacement. Another patient with a hypoplastic intraventricular septum underwent ventricular septation. Nine patients had two balanced ventricles. A ventricular septal defect was enlarged for rerouting in 3 patients. All patients had anomalous venoatrial connections and required intra-atrial baffle rerouting. One with major aortopulmonary collateral arteries underwent staged unifocalization. Three had extracardiac conduit repair. The outcomes were compared with 97 patients who underwent the Fontan procedure.

RESULTS

There were 3 early deaths and 1 late death. Six survivors are in New York Heart Association functional class I or II. Two are free from medications. Two required reoperation owing to infection or prosthetic valve failure. At 1 year, cardiac index and systemic venous pressure were 3.2 +/- 0.9 L.min(-1).m(-2) and 6.6 +/- 1.6 mm Hg, respectively. There were no significant differences in survival, freedom from arrhythmia, freedom from reoperation, or exercise tolerance between biventricular repair and the Fontan procedure.

CONCLUSIONS

Biventricular repair provided good long-term outcomes in patients with right atrial isomerism. In selected circumstances, biventricular repair is an acceptable alternative to the Fontan procedure.

The role of the Fontan procedure in the surgical treatment of congenital heart malformations with double-outlet right ventricle

The Fontan procedure in one of its many modifications is applicable to the surgical treatment of those patients with double-outlet right ventricle who are not amenable to bi-ventricular correction. Included in this group are patients with significant hypoplasia of one of the ventricles, patients with distant (non-committed) ventricular septal defect, patients with significant straddling of the atrioventricular valves, patients with abnormal atrioventricular connections (such as absence of one of the valves), or common atrioventricular valve connection. The presence of complex associated lesions such as those seen in the heterotaxia syndromes may, by virtue of the surgical risk of attempts at bi-ventricular repair, make the Fontan approach a suitable option for these patients. The presence of a subaortic conus and the potential for subaortic obstruction, a frequent findings in patients with double outlet right ventricle, plays an important role in the preparation and conduct of the Fontan operation. Copyright 2000 by W.B. Saunders Company

Double-outlet right ventricle with non-committed ventricular septal defect

OBJECTIVE

The term non-committed was used to define hearts in which the VSD was anatomically related to, or was close to, neither great vessel, being separated from both by considerable muscle. We report our experience of the surgical management of this subset, considered being of particular surgical relevance.

METHODS

Between January 1987 and December 1997, 23 patients having double-outlet right ventricle (DORV) with non-committed VSD underwent biventricular repair. Nine (39%) had undergone previous palliation. The median age was 20 months and the median weight was 8.5 kg. Two main types of repair were used: intraventricular baffle repair (n = 21) and arterial switch operation with VSD to pulmonary artery baffle (n = 2). At repair, 12 (52%) patients required concomitant VSD enlargement. In two other patients presenting with restrictive inlet VSD associated with tricuspid attachments, crossing the subaortic pathway biventricular repair was abandoned at operation.

RESULTS

There were two hospital deaths (9%, 70% CL: 3-19%). Eight patients (35%, 70% CL: 23-48%) underwent nine reoperations, six for subaortic stenosis. No late death occurred. At last visit, all patients were asymptomatic and only two had cardiac medication.

CONCLUSIONS

The biventricular repair of DORV with non-committed VSD is feasible in the vast majority of cases with comparable results to other subsets of DORV. After repair, the subaortic region is at risk for development of subaortic stenosis.