Right Ventricular Sinus Myectomy for Pulmonary Atresia with Intact Ventricular Septum: Predictors of Successful Biventricular Repair and Growth of Right-Sided Structures
R. Bryant, E. R. Nowicki, E. H. Blackstone, J. Rajeswaran, B. W. Duncan, G. L. Rosenthal, U. Mohan, M. Mumtaz, R. B. Mee. Cleveland Clinic, Cleveland, OH,
BACKGROUND: To assess outcomes of selective right ventricular (RV) sinus myectomy for pulmonary atresia with intact ventricular septum (PAIVS) in hearts believed suitable for two-ventricle repair. Specifically, we sought to determine (1) prevalence of biventricular, single-ventricle, and 1½-ventricle repair, (2) anatomic features associated with increased likelihood of biventricular repair, and (3) growth of right-sided cardiac structures.
METHODS: Medical records, echocardiograms, catheterization studies, and follow-up data from 43 PAIVS patients treated from 10/1993-6/2005 were evaluated. Serial echocardiographic measurements of right-sided cardiac structures were converted to Z-values to estimate their growth relative to somatic growth.
RESULTS: To date, 29 patients have undergone definitive repair, including 19 biventricular, 8 single-ventricle, and 2 1½-ventricle repairs. Biventricular repair was achieved in 13/15 patients (87%) who underwent RV sinus myectomy. Anatomic predictors of biventricular repair included a well-formed RV infundibulum (a priori selection feature for RV sinus myectomy), greater tricuspid regurgitation (P<.003), and tricuspid valve Z-score >≈-7 (P<.0008). Initial mean RV cavity Z-score was -1.78 in patients undergoing RV sinus myectomy, increasing to 0 afterward. Tricuspid valve Z-score and other right-sided cardiac structures did not change appreciably over time, regardless of ultimate definitive repair (Figure). Five-year survival after the last operation was 67% for the entire cohort and 73% for patients undergoing RV sinus myectomy.
CONCLUSIONS: RV sinus myectomy for PAIVS has led to biventricular repair in 87% of patients identified as suitable for it. However, tricuspid valve growth is minimal despite an enlarged RV. Thus, its size both predicts and limits successful biventricular repair; initial Z-score ≥-7 predicts high likelihood of biventricular repair.
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