Risk factors and progression of systolic anterior motion after mitral valve repair

Objectives The phenomenon of systolic anterior motion (SAM) of the mitral valve (MV) was discovered 50 years ago, but to date only a few studies have identified risk factors for SAM following mitral repair. There are limited data on the necessity of surgical reintervention on the MV once SAM is discovered by intraoperative transesophageal echocardiography. We sought to identify predictors of SAM in a large cohort of consecutive patients, assess the rate of early reintervention on the MV to address SAM, and follow the progression of SAM postdischarge. Methods Analysis of electronically stored echocardiographic exams of adults who underwent MV repair in a recent decade. Results Following MV repair, the incidence of SAM immediately after cardiopulmonary bypass was 13% (98 of 761 patients). Multivariable analysis revealed several preoperative risk factors of SAM development and progression, including a lower ratio of anterior to posterior leaflets heights, younger age, lower end-systolic left ventricular volume, presence of bileaflet prolapse, and male sex. SAM was managed conservatively in 91 patients (93%) and surgically in 7 patients (7%). In a majority of patients (70 of 98 patients [71%]) SAM resolved before hospital discharge. Conclusions Transesophageal echocardiography findings associated with SAM were excessive height of posterior to anterior mitral leaflet, smaller left ventricular end-systolic volume, and bileaflet prolapse. Conservative management of SAM was usually successful, and persistent hemodynamically significant SAM was uncommon. Prophylactic modification of the surgical technique to avoid SAM seems unnecessary for all but those at highest risk for developing SAM.