LAUSR

OBJECTIVES Cleft-like indentations (CLIs) of the mitral valve (MV) are best assessed with three-dimensional (3D) transesophageal echocardiography (TEE). The present study examined the prevalence, characteristics, and surgical effect of MV CLIs in patients with hypertrophic cardiomyopathy (HCM). DESIGN Prospective, observational, case-control study. SETTING Tertiary medical center. PARTICIPANTS The study comprised 90 patients with HCM undergoing myectomy and 59 patients undergoing cardiac surgery for non-MV related indications. MEASUREMENTS AND MAIN RESULTS Intraoperative 3D TEE was used to evaluate the presence and characteristics of MV CLIs compared, with a random control group of 59 patients undergoing cardiac surgery for non-MV related indications. Ninety patients with HCM (mean age 54.8 ± 13.3 y, 67.8% male) were compared with 59 control patients (mean age 67 ± 12.7 y, 79.7% male). Three-dimensional TEE images were interpreted by consensus of two experienced echocardiographers. At least one MV CLI was present in 84 patients with HCM (93.3%), compared with 23 control patients (39%; p < 0.01). Compared with control patients, patients with HCM were more likely to have deep MV CLIs (85.6% v 25.4%; p < 0.01) and ≥2 CLIs (52.2% v 26.1%; p = 0.02). Six HCM patients (7%) appeared to have true congenital posterior leaflet clefts versus 0% in control patients (p = 0.08). Preoperative mitral regurgitation severity and jet direction were not associated with the presence of deep or multiple MV CLIs (all p > 0.2). None of the MV CLIs in the HCM group required MV surgical intervention or second pump runs for MV regurgitation correction after myectomy. CONCLUSION Deep and multiple MV CLIs are common in patients with HCM undergoing septal myectomy, including possible true posterior clefts, but they are not associated with the premyectomy severity of mitral regurgitation or jet direction, and do not result in surgical MV intervention.