Association of Preoperative Sleep-Disordered Breathing With Functional Status After Septal Myectomy for Obstructive Hypertrophic Cardiomyopathy

Background: Sleep-disordered breathing (SDB) is a risk factor for heart failure symptoms in patients with hypertrophic cardiomyopathy (HCM). However, the relationship between preoperative SDB and postoperative functional status after septal myectomy (SM) is unknown. In this study, we investigated the association of preoperative SDB with late self-reported health status among patients undergoing SM for obstructive HCM. Methods: Prior to SM, an overnight pulse oximetry test was used to measure oxygen desaturation index (ODI), which indicates the average number of desaturation episodes with at least 4% of drops in oxygen level from baseline per hour of sleep. Patients reported postoperative function through a questionnaire-based survey completed 3-5 years following SM. Results: We analyzed 264 patients who underwent transaortic SM from November 2005 through April 2016. On predischarge transthoracic echocardiography post-procedure, no significant difference was present in the extent of mitral valve regurgitation (P = 0.524), left ventricular outflow tract gradient (P = 0.405), or septal thickness (P = 0.744) related to ODI. At 3 to 5 years after their operation, 236 patients (89%) reported good or excellent health. Approximately 18% (n = 48) and 8% (n = 22) of the cohort continued to experience exertional dyspnea and chest tightness, respectively, on walking 2 blocks or less. A greater ODI was not an independent predictor of worse health status or residual symptoms. Conclusions: Relief of left ventricular outflow tract obstruction in patients with obstructive HCM improves symptoms, with 89% of patients reporting good or excellent health. Preoperative SDB is not significantly associated with late functional status after septal myectomy.