Targeted Increase in Pulmonary Blood Flow in a Bidirectional Glenn Circulation

A Review of Biventricular Repair for the Congenital Cardiac Anesthesiologist

The management of children with a borderline ventricle has been debated for many years. The pursuit of a biventricular repair in these children aims to avoid the long-term sequelae of single ventricle palliation. There is a lack of anesthesia literature relating to the care of this complex heterogenous patient population. Anesthesiologists caring for these patients should have an understanding on the many different forms of physiology and the impact on provision of anesthesia and hemodynamic parameters, the goals of biventricular staging and completion as well as the pre-operative, intra-operative, and post-operative considerations relating to this high-risk group of patients.

Management of failing bidirectional cavopulmonary shunt: Influence of additional systemic-to-pulmonary-artery shunt with classic Glenn physiology

Objectives

Methods

Results

Conclusions

Reaching consensus for unified medical language in Fontan care

Aims

The Fontan operation has resulted in improved survival in patients with single‐ventricle congenital heart disease. As a result, there is a growing population of teenagers and adults with a Fontan circulation. Many co‐morbidities have been increasingly recognized in this population due to the unique features of the Fontan circulation. Standardization of how Fontan co‐morbid conditions are defined will help facilitate understanding, consistency and interpretability of research and clinical experience. Unifying common language usage in Fontan is a critical precursor step for data comparison of research findings and clinical outcomes and ultimately accelerating improvements in management for this growing group of patients. This manuscript aimed to create unified definitions for morbidities seen after the Fontan palliation.

Methods

In association of many congenital heart disease organizations, this work used Delphi methodology to reach a broad consensus among recognized experts regarding commonly used terms in Fontan care and research. Each definition underwent at least three rounds of revisions to reach a final definition through surveys sent to experts in the field of single‐ventricle care.

Results

The process of reaching a consensus on multiple morbidities associated with the Fontan procedure is summarized in this manuscript. The different versions that preceded reaching the consensus are also presented in the Supporting Information. Table 1 represents the final definitions according to the consensus.

Conclusions

We propose the use of these definitions for clinical care, future research studies, registry development and clinical trials.

Restriction of Atrial Septal Defect Leads to Growth of Hypoplastic Ventricle in Patients with Borderline Right or Left Heart

Patients with borderline hypoplastic right or left ventricle and VSD may be candidates for either single ventricle palliation or staged ventricular recruitment (SVR) followed by eventual biventricular conversion. Components of SVR include restriction of atrial septal defects (ASD) without ventricular septal defects (VSD) closure and addition of accessory pulmonary blood flow. This study evaluated the impact of ASD restriction on ventricular growth and function. We retrospectively reviewed patients with borderline ventricular hypoplasia and VSD who underwent a staged ventricular recruitment (SVR) procedure from 2012 to June 2019. Pre- and post-recruitment MRI and echocardiogram data were compared and analyzed. We excluded cases in which we intentionally restricted VSD with simultaneous ASD restriction. Forty-six patients (41 with right-dominant ventricle, 25 with risk factors for Fontan procedure) underwent SVR at a median age of 15.1 months' (interquartile range (IQR), 7.2-37.2 months'). The median indexed ventricular end-diastolic volume, end-systolic volume, and stroke volume according to cardiac MRI significantly increased at median 11.0 months' (IQR:7.8~14.1 months') after recruitment. Among them, except 2 operative mortalities after SVR, 26 patients underwent bi-ventricular repair (56.5% including one and a half ventricle repair) at a median of 8.0 months' (IQR: 6.2-12.2 months') after recruitment. Fifteen patients await biventricular completion, and 3 patients underwent single ventricle palliation. Pulmonary blood flow (Qp) tended to increase after recruitment regardless of type of pulmonary blood flow modification without statistical significance. Six patients died at a median duration of 6.5 months' (IQR: 2.9-11.7) after SVR; 3 patients died after biventricular completion, 2 after recruitment, and 1 after returning to single ventricle palliation. All of them were considered poor Fontan candidates due to severe atrioventricular valve regurgitation, pulmonary hypertension, pulmonary vein stenosis, or airway stenosis. Restriction of the atrial septum leads to the growth of hypoplastic ventricle in patients with ventricular septal defects who undergo SVR regardless of the preoperative characteristics, and eventual biventricular repair can be performed in a subgroup of these patients. Future work is necessary to optimize timing of SVR and method of accessory pulmonary blood flow.

One and One-Half Ventricle Repair: Role for Restricting Antegrade Pulmonary Blood Flow

BACKGROUND

In patients with hypoplastic subpulmonary ventricles, the one and one-half ventricle (1.5V) repair is an alternative to the Fontan procedure. However, in 1.5V-treated patients with pulsatile pulmonary blood flow, superior vena cava (SVC) hypertension or right atrial hypertension may develop. This study aimed to (1) describe patient outcomes after 1.5V repair and (2) determine whether pulmonary artery septation at 1.5V repair confers a lower risk of SVC or right atrial hypertension.

METHODS

This study retrospectively reviewed patients who underwent a 1.5V repair between 1989 and 2020. The primary outcome was transplant-free survival. Secondary outcomes were postoperative SVC hypertension (defined by mean Glenn pressures greater than 17 mm Hg, SVC flow reversal or pulsatility, venovenous collateral vessels, or SVC syndrome) and right atrial hypertension (defined as mean right atrial pressures greater than 10 mm Hg with inferior vena cava and hepatic vein dilation or flow reversal).

RESULTS

A total of 74 patients underwent 1.5V repair at a median age of 29.6 months (interquartile range, 8.9 to 45.5 months). Median follow-up time was 39.9 months (interquartile range, 11.4 to 178.1 months). Transplant-free survival at 10 years was 92.4%. Among survivors, 12% (8 of 69) had right atrial hypertension and 39% (27 of 69) had SVC hypertension on follow-up. Survivors with unseptated pulmonary arteries had a greater risk of SVC hypertension compared with patients with septated pulmonary arteries (44% vs 10%; P = .04). No difference was found in right atrial hypertension between the 2 groups.

CONCLUSIONS

Patients with 1.5V repair avoid Fontan-associated complications with favorable transplant-free survival. However, SVC hypertension remains a significant long-term complication. Pulmonary artery septation at 1.5V repair may reduce the risk of SVC hypertension.

Super Glenn for staged biventricular repair: impact on left ventricular growth?

 

OBJECTIVES

The Super Glenn procedure involves targeted increased in blood flow to left sided heart structures with fenestrated atrial septation. The objective of this study was to examine the outcomes of patients who had this procedure as a part of biventricular staging and specifically evaluate the effect on dimensions of left heart structures.

METHODS

Data for patients who had this procedure between 2005 and 2019 were retrospectively identified.

RESULTS

Thirty-seven patients were identified. Most common diagnosis was hypoplastic left heart syndrome in 40% (n = 15). On echocardiography, the median mitral valve z score was -2.26. On cardiac magnetic resonance imaging, median indexed left ventricular end-diastolic volume was 31.5 ml/m2 and mitral/tricuspid inflow ratio was 0.35. The median age at Super Glenn was 2.3 years (interquartile range 1.5-3.6) while median weight was 12 kg (interquartile range 9.8-14). There were no early/hospital deaths. The median intensive care unit length of stay was 4 days, and median hospital length of stay was 10 days. Median follow-up for the entire cohort was 3 years (range 15 days to 13.2 years). There was a statistically significant increase in indexed left ventricular dimensions. There were 5 deaths (14%). Three patients (8%) underwent heart transplant. Freedom from death/transplant was 79% at 5 years. Seven patients (19%) needed a reoperation. Twenty-three patients (62%) underwent biventricular conversion after a median of 11.3 months after Super Glenn.

CONCLUSIONS

The Super Glenn procedure achieves consistent increase in left ventricular dimensions. This may be a useful strategy to help achieve a successful biventricular circulation in patients with borderline left ventricle. The superiority/non-inferiority of this approach over the conventional Fontan pathway is unclear.

Left Ventricular Recruitment in Patients With Hypoplastic Left Heart Syndrome

Hypoplastic left heart complex with "borderline left ventricle" and intact ventricular septum is a clinical conundrum for the congenital heart surgeon. The choice between neonatal biventricular repair and single ventricle palliation can be challenging, and the current tools to aid in the decision-making process fail to account for the morbidity associated with intermediate and late diastolic dysfunction. Staged ventricular recruitment, consisting of valvular repair techniques, resection of endocardial fibroelastosis, atrial septal restriction, and augmentation of pulmonary blood flow, has been shown to improve left ventricular size and function culminating in eventual biventricular circulation. Despite staged ventricular recruitment, some patients cannot undergo biventricular conversion. Strategies to address these complex patients, including the "reverse" double switch, are the next frontier in biventricular repair.

Biventricular Conversion in the Borderline Hypoplastic Heart

PURPOSE OF REVIEW

The development of biventricular repair and conversion pathways for patients with borderline hypoplastic heart disease represents an area of recent inquiry and innovation. This review summarizes emerging techniques and novel treatment algorithms for borderline hypoplastic heart disease with a focus on surgical advances within the last 10 years.

RECENT FINDINGS

Many patients with borderline hypoplastic heart disease are amenable to primary biventricular repair, or biventricular conversion following single-ventricle palliation coupled with ventricular rehabilitation strategies. New insights into the potential for growth and recovery of borderline ventricles have been uncovered. However, questions remain regarding optimal patient selection and the long-term outcomes of select patient groups treated with single-ventricle palliation versus biventricular repair/conversion or transplantation. Efforts to direct a greater proportion of borderline hypoplastic heart patients towards a biventricular circulation are accelerating and represent important avenues for progress and future research in the field of congenital heart disease.

Superior Cavopulmonary Connection: Its Physiology, Limitations, and Anesthetic Implications

The superior cavopulmonary connection (SCPC) or "bidirectional Glenn" is an integral, intermediate stage in palliation of single ventricle patients to the Fontan procedure. The procedure, normally performed at 3 to 6 months of life, increases effective pulmonary blood flow and reduces the ventricular volume load in patients with single ventricle (parallel circulation) physiology. While the SCPC, with or without additional sources of pulmonary blood flow, cannot be considered a long-term palliation strategy, there are a subset of patients who require SCPC palliation for a longer interval than the typical patient. In this article, we will review the physiology of SCPC, the consequences of prolonged SCPC palliation, and modes of failure. We will also discuss strategies to augment pulmonary blood flow in the presence of an SCPC. The anesthetic considerations in SCPC patients will also be discussed, as these patients may present for noncardiac surgery from infancy to adulthood.

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.