Myectomy with and without Mitral Subvalvular Repair in Patients with Hypertrophic Obstructive Cardiomyopathy with Grade 3 to 4+Mitral Regurgitation without Intrinsic Mitral Valve Disease: A Retrospective Observational Study

Background: Hypertrophic obstructive cardiomyopathy (HOCM) with severe mitral regurgitation (MR) remains controversial for the choice of the concomitant mitral valve (MV) management versus septal myectomy alone. The impacts of different surgical strategies (concomitant mitral subvalvular procedures versus myectomy alone) on one-year results of surgical treatment of HOCM with grade 3 to 4+ MR without intrinsic MV disease were evaluated in this single-center, retrospective observational study. Methods: A total of 146 eligible patients were retrospectively screened into a combined group (n = 40) and an alone group (n = 106), depending on whether they underwent transaortic mitral subvalvular procedures. Perioperative outcomes were collected, and results at 1-year following surgery were compared. Results: Surgical mortality did not differ (0 for combined group vs. 0.9% for alone group, p = 0.538). Six patients (5.0% vs. 3.8%, p = 0.666) developed postoperative complete atrioventricular node block with permanent pacemaker implantation. No death or reoperation was recorded during a median follow-up of 18 months. At 1-year following surgery, (1) the provoked MR severity decreased from baseline in both groups with a significant difference between groups [1.0 (0-1.0) vs. 1.0 (1.0-1.3), p < 0.001]; (2) systolic anterior motion (SAM) was observed in 10 patients (0 vs. 10 in the alone group, p = 0.043); (3) the provoked gradient was also significantly lower than baseline value for each group, with a significant difference between the two groups (8.8 +/- 4.3 mmHg vs. 12.1 +/- 6.7 mmHg, p = 0.006); and (4) New York Heart Association class decreased from baseline value for each group (p < 0.001). Conclusions: In HOCM patients with grade 3 to 4+ MR without intrinsic MV disease, mitral subvalvular management during septal myectomy may be associated with a low incidence of SAM, improved MR, and a lower outflow tract gradient in comparison with septal myectomy alone.

Automated summary

The study suggests that in HOCM patients with severe MR but without intrinsic MV disease, mitral subvalvular management during septal myectomy may lead to reduced MR severity, lower outflow tract gradient, and decreased incidence of SAM.