Association Between Three-Dimensional Left Ventricular Outflow Tract Area and Gradients After Myectomy in Hypertrophic Obstructive Cardiomyopathy

Determine whether the intraoperative three-dimensional left ventricular outflow tract cross-sectional area may be inversely correlated with pressure gradients as a determinant of surgical success after septal myectomy in hypertrophic cardiomyopathy patients. Perioperative data were obtained by retrospective review. Toronto General Hospital, University of Toronto, Toronto, Canada, a tertiary hospital. The study comprised 67 patients with hypertrophic obstructive cardiomyopathy. Transthoracic and intraoperative transesophageal echocardiographic assessment of pressure gradients. Transesophageal measurement of the three-dimensional left ventricular outflow tract cross-sectional area. The smallest left ventricular outflow tract area increased on average 1.883 cm2 (98.3%) after septal myectomy. There was a significant correlation between the increase in the area and the transesophageal pressure gradients (r = –0.32; p = 0.01) after myectomy, but none with postoperative transthoracic gradients at rest (r = –0.10; p = 0.42). Postoperative transesophageal and transthoracic gradients were significantly correlated (r = 0.26; p = 0.04). The best risk factors to predict high residual gradients were preoperative transesophageal gradient >97 mmHg, postoperative transesophageal area