Late clinical outcome of transient intraoperative systolic anterior motion post mitral valve repair.

Objective: Systolic anterior motion (SAM) after mitral valve repair with significant mitral regurgitation requires immediate reintervention. Transient SAM immediately after repair is usually managed by hemodynamic maneuvers. We investigated the late clinical and echocardiographic significance of postoperative transient SAM. Methods: Between 2004 and 2013, mitral valve repair was performed on 549 consecutive patients with degenerative mitral valve disease. Of the 45 patients (8.2%) identified with postrepair SAM, 5 needed immediate reintervention. Hemodynamic maneuvers, such as preload and afterload augmentation and rate control, effectively abolished SAM in 40 patients (SAM). They were followed and compared with the remaining 509 patients (non-SAM). Results: Mean clinical follow-up was 54 +/- 28 and 31 +/- 26 months and was available in 100% and 95%(SAM and non-SAM) patients, respectively. One hospital death occurred in each group (P = .14). At follow-up, 2 patients (0.3%) showed significant SAM with left ventricular outflow tract obstruction, which resolved in 1 patient after beta-blocker therapy. SAM patients underwent exercise stress echocardiography: 1 patient showed left ventricular outflow tract obstruction that worsened after exercise. At 5 years, freedom from moderate or severe mitral regurgitation and New York Heart Association functional class III-IV was 85% versus 92%(P = .27) and 81% versus 92%(P = .15), and freedom from reoperation was 100% and 96% (P = .4), in SAM and non-SAM patients, respectively. Conclusions: Late postoperative exercise stress echocardiogram revealed low incidence of SAM in patients with immediate postrepair transient SAM. All other late clinical outcomes were similar to those of non-SAM repair patients. Conservative management of intraoperative transient SAM is both successful and reliable.