Surgical Decision-Making in Neonates with Borderline Left Ventricular Hypoplasia without Significant Aortic or Mitral Valve Stenosis using Cardiovascular Magnetic Resonance

Abstract Background Most patients with significant left ventricular (LV) hypoplasia undergo single ventricle (SV) palliation, but biventricular (Bi-V) repair is viable in some patients with borderline LV hypoplasia. We sought to identify CMR (cardiovascular magnetic resonance) criteria predictive of successful primary Bi-V repair in neonates with borderline LV hypoplasia without significant stenosis of the mitral valve (MV) and aortic valve (AV), and to determine reasons for reintervention after successful Bi-V repair. Methods This retrospective study included all patients with borderline LV hypoplasia who underwent CMR from 2003-2024 for surgical decision-making. Patients with abnormal segmental connections, atrioventricular septal defects, unrestrictive ventricular septal defects, those with more than mild MV stenosis (mean Doppler flow gradient > 5 mmHg) and/or more than mild AV stenosis (peak Doppler flow gradient >20 mmHg) were excluded. Patients were divided into two groups based on initial intervention - primary Bi-V repair and hybrid/ other staging procedure. Outcomes were categorized as successful primary Bi-V repair, successful staged Bi-V repair and failure to achieve Bi-V repair (hybrid followed by SV palliation, transplant, death). Fisher exact test and Mann-Whitney U test was utilized to explore potential relationships. ROC curves were used to test diagnostic accuracy of parameters to predict successful primary Bi-V repair. Results Among 37 patients meeting the inclusion criteria, 23 (62%) patients underwent successful primary Bi-V repair, 8 (22%) underwent staged Bi-V repair, 6 (16%) failed to achieve Bi-V repair. Patients who underwent successful primary/ staged Bi-V repair had higher values for left ventricular diastolic volume index (LVEDVi 28 mL/m 2 vs. 17.4.00 mL/m 2 ; p 27 mL/m 2 and Q Ao is > 1.99 L/min/m 2 .