Abstract 9936: Cardiac Magnetic Resonance Factors Associated With Successful Univentricular to Biventricular Conversion in Small Left Hearts
Background: In patients (pts) with small left heart structures, the decision to attempt conversion from a univentricular to biventricular (BiV) circulation has profound consequences, but preoperative factors predicting success are not well established. We sought to identify cardiac magnetic resonance imaging (CMR) parameters associated with successful BiV conversion.
Methods: All pts with hypoplastic left heart structures and univentricular physiology who underwent CMR prior to an attempted BiV conversion were retrospectively identified. Subjects were divided into 2 anatomic groups: 1) right-dominant atrioventricular canal defect (AVC), and 2) small left heart structures without an AVC defect (SLH). Successful BiV conversion was defined as a BiV circulation at latest follow-up.
Results: In the SLH group, there were 20 pts who underwent BiV conversion at a median age of 38.5 months (0-82) and 15 (75%) were successful with a median follow-up of 12 months (0-64). Pts with successful BiV conversion had a higher median left ventricular end-diastolic volume (LVEDV) (61 vs. 27 ml/m2, p=0.006), higher median LV/RV stroke volume ratio (0.9 vs. 0.2, p=0.004), and a trend towards higher median mitral/tricuspid inflow ratio (1.1 vs. 0.7, p=0.08). LVEDV ≥30 ml/m2 was associated with higher percentage of successful conversion (88 vs. 25%, p=0.02); 3 of the 4 pts with LVEDV <30 ml/m2 were unsuccessful. Late gadolinium enhancement (LGE) consistent with endocardial fibroelastosis (EFE) was present in 15 pts (75%) and was not associated with failed conversion (p=0.56), although 14 pts (93%) underwent EFE resection either before or after CMR. In the AVC group, there were 10 pts who underwent BiV conversion at a median age of 6.5 months (2-75) and all were successful. Minimum values were LVEDV 22ml/m2, LV/RV stroke volume ratio 0.2, and mitral/tricuspid area ratio 0.3. None had LGE.
Conclusion: In SLH pts, CMR derived LVEDV and LV/RV stroke volume ratio but not LGE are associated with successful BiV conversion. In AVC pts, the high rate of successful BiV conversion precluded discriminant analysis, but the range of CMR parameters permitting success is provided. These data aid in the interpretation of CMR results in pts being considered for a BiV conversion.
- Cardiac MRI
- Pediatric cardiology
- Congenital heart disease
- Hypoplastic left heart
- Congenital heart surgery
- © 2012 by American Heart Association, Inc.