Concomitant Septal Myectomy in Patients Undergoing Aortic Valve Replacement for Severe Aortic Stenosis

BACKGROUND: Patients with severe aortic stenosis (AS) are often found to have asymmetric septal hypertrophy (ASH). With low sensitivity of echocardiography for detecting dynamic left ventricular outflow tract (LVOT) obstruction in severe AS, we adopted a routine intraoperative inspection of LVOT strategy for aortic valve replacement (AVR), and performed concomitant septal myectomy (CSM) as necessary. We sought to (1) evaluate surgical outcomes of CSM, (2) suggest preoperative echocardiographic parameters that correlate with findings of ASH, and (3) determine the predictors of CSM. METHODS AND RESULTS: A single surgeon performed AVR for moderate-to-severe AS in 301 patients from 2007 to 2012. CSM was performed in 35 (11.6%) patients, resulting in AVR vs. AVR+CSM groups. Echocardiographic parameters, including the ratio of LVOT to aortic annular diameter (LVOT/AA), were compared. Mortality rate was comparable between groups (P=0.37). There were no postoperative complications related to CSM. The AVR+CSM group had a smaller LVOT/AA ratio (P=0.0012). The predictor of CSM was implanted valve size ≤ 21 mm (odds ratio 3.2, confidence interval 1.54-6.65, P=0.002). CONCLUSIONS: CSM can be performed safely at the time of AVR. The preoperative echocardiographic LVOT/AA ratio may help in detecting ASH. As an implanted valve size ≤ 21 mm was the only risk factor for CSM, careful assessment of LVOT is important in patients with a small aortic annulus.