Sleep Disordered Breathing and Mortality in Patients With Hypertrophic Obstructive Cardiomyopathy Undergoing Septal Myectomy

Objective: To determine the impact of sleep-disordered breathing (SDB) on survival in patients with hypertrophic cardiomyopathy (HCM) following septal myectomy. Patients and Methods: Patients with obstructive HCM undergoing septal myectomy from 2007 to 2016 were reviewed. Those who had an overnight oximetry test within 6 months before myectomy were included in analysis. Oxygen desaturation index was examined continuously and also categorically (SDB [>5/h] and severe SDB [>15/h]). Results: A total of 619 of 1500 patients undergoing septal myectomy had overnight oximetry tests. Sleep-disordered breathing (oxygen desaturation index >5/h) was identified in 338 (54.6%) patients, and among those patients, 117 (18.9%) were classified as severe. Patients with SDB were older, had greater body mass index and body surface area, were more likely to have arterial hypertension and atrial fibrillation, and had an increased E/e’ ratio on Doppler echocardiography. Notably, there was no difference in preoperative resting left ventricular outflow tract pressure gradient between patients with SDB and those with normal overnight oximetry (55 (interquartile range: 25 to 86) mm Hg versus 52 (interquartile range: 21 to 85) mm Hg; P=.29). There was no difference in age-adjusted survival among patients with normal oximetry compared with those with mild SDB (hazard ratio: 0.98; 95% CI: 0.45 to 2.17), and severe SDB (hazard ratio: 1.06, 95% CI 0.42 - 2.71). Conclusion: Sleep-disordered breathing is present in more than half of patients with obstructive HCM in whom septal myectomy is indicated, and is mainly associated with aging, overweight, and male sex. However, SDB does not alter survival following septal myectomy.