Abstract
BackgroundWe sought to identify cardiovascular magnetic resonance (CMR) parameters associated with successful univentricular to biventricular conversion in patients with small left hearts.MethodsPatients with small left heart structures and a univentricular circulation who underwent CMR prior to biventricular conversion were retrospectively identified and divided into 2 anatomic groups: 1) borderline hypoplastic left heart structures (BHLHS), and 2) right-dominant atrioventricular canal (RDAVC). The primary outcome variable was transplant-free survival with a biventricular circulation.ResultsIn the BHLHS group (n = 22), 16 patients (73%) survived with a biventricular circulation over a median follow-up of 40 months (4–84). Survival was associated with a larger CMR left ventricular (LV) end-diastolic volume (EDV) (p = 0.001), higher LV-to-right ventricle (RV) stroke volume ratio (p < 0.001), and higher mitral-to-tricuspid inflow ratio (p = 0.04). For predicting biventricular survival, the addition of CMR threshold values to echocardiographic LV EDV improved sensitivity from 75% to 93% while maintaining specificity at 100%. In the RDAVC group (n = 10), 9 patients (90%) survived with a biventricular circulation over a median follow-up of 29 months (3–51). The minimum CMR values were a LV EDV of 22 ml/m2 and a LV-to-RV stroke volume ratio of 0.19.ConclusionsIn BHLHS patients, a larger LV EDV, LV-to-RV stroke volume ratio, and mitral-to-tricuspid inflow ratio were associated with successful biventricular conversion. The addition of CMR parameters to echocardiographic measurements improved the sensitivity for predicting successful conversion. In RDAVC patients, the high success rate precluded discriminant analysis, but a range of CMR parameters permitting biventricular conversion were identified.
Highlights
We sought to identify cardiovascular magnetic resonance (CMR) parameters associated with successful univentricular to biventricular conversion in patients with small left hearts
Seventeen patients (77%) underwent a prior procedure designed to increase blood flow into the left ventricular (LV) by providing an additional source of pulmonary blood flow (e.g., Blalock-Taussig shunt in a patient with a bidirectional Glenn shunt), and/or by restricting the atrial septal defect to direct more of the pulmonary venous return into the LV
We found that a greater LV end-diastolic volume (EDV), LV-to-right ventricle (RV) stroke volume ratio, and Mitral valve (MV)-to-Tricuspid valve (TV) inflow ratio were associated with a higher rate of survival with a biventricular circulation in patients with Borderline hypoplastic left heart structures (BHLHS)
Summary
We sought to identify cardiovascular magnetic resonance (CMR) parameters associated with successful univentricular to biventricular conversion in patients with small left hearts. At one end of the spectrum, patients may have severe ventricular hypoplasia and/or valve atresia rendering a biventricular circulation with the pulmonary and systemic ventricles This clinical dilemma most commonly arises in the context of 2 anatomic diagnoses: 1) patients who have various combinations of left-sided valvar hypoplasia and stenosis (mitral and/or aortic), left ventricular (LV) hypoplasia, and aortic coarctation (borderline hypoplastic left heart structures, BHLHS); and 2) those who have right-dominant atrioventricular canal defects (RDAVC) with variable degrees of right ventricular (RV) dominance, abnormalities of the left ventricular papillary muscle and chordal architecture, and left ventricular hypoplasia. We sought to identify CMR parameters associated with successful conversion from a univentricular to biventricular circulation
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