Aortic valve replacement with or without concomitant septal myectomy in patients with aortic stenosis and asymmetric septal hypertrophy: a retrospective cohort study

The optimal surgical strategy for patients with severe aortic stenosis (AS) accompanied by asymmetric septal hypertrophy (ASH) remains controversial. This study aimed to evaluate the safety and efficacy of concomitant septal myectomy performed at the time of aortic valve replacement in this population. Between January 2020 and December 2025, among 6449 consecutive patients who underwent aortic valve replacement, 39 met the inclusion criteria of severe AS with concomitant ASH (interventricular septal thickness ≥ 15 mm). 22 patients underwent concomitant septal myectomy with AVR, while 17 underwent isolated AVR. Baseline characteristics, perioperative outcomes, echocardiographic parameters, and mid-term follow-up results were compared between groups. Baseline clinical characteristics were largely comparable between groups, although patients in the myectomy with AVR group exhibited more severe preoperative left ventricular outflow tract obstruction (LVOTO) and a higher prevalence of moderate-to-severe mitral regurgitation. Early postoperative echocardiography demonstrated significantly lower LVOT peak velocity and pressure gradient, as well as reduced interventricular septal thickness, in the myectomy with AVR group. Two early deaths occurred in the myectomy with AVR group. At a mean follow-up of 3.11 years, LVOT hemodynamics and prosthetic valve function remained satisfactory in both groups, while left ventricular end-diastolic and end-systolic dimensions were significantly smaller in the myectomy with AVR group. In patients with severe AS and concomitant ASH, both isolated AVR and AVR with concomitant septal myectomy are feasible surgical strategies in selected patients. Isolated AVR was associated with a marked early postoperative elevation in LVOTPG,, suggesting that relief of fixed valvular obstruction may unmask dynamic subvalvular obstruction. Concomitant myectomy eliminates this early hemodynamic vulnerability by directly relieving subvalvular obstruction, and may be particularly beneficial in patients with higher preoperative LVOTPG. This strategy should be performed at centers with established myectomy expertise, and larger prospective studies are needed to define optimal patient selection criteria.