The following is the summary of “Is anterior mitral valve leaflet length important in outcome of septal myectomy for obstructive hypertrophic cardiomyopathy?” published in the January 2023 issue of Thoracic and cardiovascular surgery by Carvalho, et al.

Some surgeons recommend the application of the anterior mitral valve leaflet in conjunction with septal myectomy to address the phenotypic characteristic of hypertrophic cardiomyopathy, mitral valve leaflet elongation. Mitral valve leaflet length and results after septal myectomy for obstructive hypertrophic cardiomyopathy are the focus of the current investigation. Between February 2015 and April 2018, 564 patients with obstructive hypertrophic cardiomyopathy had transaortic septal myectomy, and researchers analyzed their medical records and echocardiograms. The typical treatment involved an extensive septal myectomy without plication of the anterior leaflet. The coaptation length between the anterior and posterior mitral valve leaflets was determined from intraoperative prebypass transesophageal echocardiograms. These mitral valve leaflet measurements were also performed on 92 individuals receiving aortic valve replacement and 90 patients undergoing isolated coronary artery bypass grafting during the same time period.

Investigators evaluated the relationship between the length of the heart’s leaflets, the degree to which the left ventricular outflow tract gradient is relieved, and the patients’ ability to survive for a full year after septal myectomy for hypertrophic cardiomyopathy. Patients’ ages ranged from 50.2 to 67.7 (median: 60.3), with males making up 54.1% of the total. 36 patients (6.4%), mostly for intrinsic mitral valve disease, required concomitant mitral valve repair, and 8 patients (1.4%) required mitral valve replacement. The mitral valve leaflet measurements of patients with hypertrophic cardiomyopathy were statistically considerably longer than those of individuals following CABG or aortic valve replacement (P<.001 for all 3 measurements). Resting gradients in the left ventricular outflow tract prior to surgery did not differ significantly between groups defined by leaflet length (30 mm, median 49 [21, 81.5] mm Hg vs. 30 mm, 50.5 [21, 77] mm Hg; P=.76). Also, the length of the patient’s anterior leaflets had no bearing on the degree of gradient reduction after myectomy, with the median gradient reduction being 33 (69, 6) mm Hg for patients with leaflet length 30 mm or less and 36.5 (62, 6) mm Hg for patients with leaflet length 30 mm or more (P=.36). 

There was no significant correlation between the size of the anterior mitral valve leaflet and the risk of dying within a year (P=.758). Previous research has shown that people with hypertrophic cardiomyopathy have somewhat elongated mitral valve leaflets, and our study verifies this observation. Higher left ventricular outflow tract gradients were not linked to had longer anterior mitral valve leaflets, in contrast to previous results. Importantly, study group did not find any correlation between the length of the front mitral valve leaflet and the resting gradient or gradient relief in the left ventricular outflow tract after surgery. Therefore, in the absence of intrinsic mitral valve dysfunction, transaortic septal myectomy is sufficient for most individuals so long as the excision is made beyond the point of septal contact.