Echocardiography before and after resect-plicate-release surgical myectomy for obstructive hypertrophic cardiomyopathy

Background Anatomic features of obstructive hypertrophic cardiomyopathy are septal hypertrophy, elongated mitral leaflets, and anterior displacement of the papillary muscles. In addition to extended myectomy, the resect-plicate-release operation adds horizontal plication of the anterior mitral leaflet (AML) and release of the anterolateral papillary muscle (APM) in selected patients. The aim of this study was to test the hypotheses that (1) preoperative findings would be associated with procedures applied, (2) anatomic corrections would be observable postoperatively, and (3) there would be consistently good physiologic outcomes. Methods A retrospective study was conducted of patients with obstructive hypertrophic cardiomyopathy who had adequate echocardiograms before and 9.5 ± 12 months after the resect-plicate-release operation was performed from 2006 to 2012. Results Seventy-seven patients underwent myectomy, 50 AML plication, and 50 APM release. Patients who underwent plication had longer AMLs (32 ± 4 vs 28 ± 4 mm; P <.004). Anterior extension of the APM was more common with papillary muscle release (86% vs 62%, P <.04). Twenty-seven (35%) had septal thickness ≤ 18 mm; mitral valve-sparing operations were possible because of plication in 19 patients (70%), papillary release in 21 (78%), and one or both in 96%. Patients who underwent plication had decreased AML length by 16%, residual leaflet length by 33%, and protrusion by 24%. After APM release, there was decreased distance from mitral coaptation to the posterior wall. Surgery abolished severe systolic anterior motion and resting gradients and reduced mitral regurgitation. Conclusions Echocardiographic AML length and directly observed slack provides a basis to recommend performance of plication and define its extent; plication decreases AML protrusion and stiffens the leaflet. Anterior APM recommends release, which drops the coaptation point posteriorly. Systematic relief of all aspects of obstructive pathophysiology results in consistent outcomes.