Anterior mitral leaflet length and mitral annulus diameter impact the echocardiographic outcome after isolated myectomy

Abstract

BackgroundMyectomy remains the standard surgical treatment of patients with hypertrophic cardiomyopathy (HOCM). New surgical methods developed in the last decades mainly address the mitral valve and are controversial because of their conflicting assumptions. This study assesses the influence of anterior mitral valve leaflet (AML) length and the anterior-posterior diameter of the mitral annulus (MAD) on dynamic left ventricle outflow tract obstruction and mitral regurgitation (MR) after extended myectomy.MethodsWe retrospectively analysed the transthoracic echocardiograms (TTE) of 36 patients. AML length and MAD were obtained from TTE performed before the operation. The greatest maximal left ventricle outflow tract (LVOT) gradient and MR registered in follow-up were analysed. After surgery, patients were divided into two groups; those with moderate or milder MR and/or an LVOT gradient < 30 mmHg (responders), and those with more than moderate MR and/or an LVOT gradient ≥30 mmHg (non-responders).ResultsPatients in responders group had significantly longer AML: 32.3 ± 2.3 mm vs 30.0 ± 3.8 mm (p = 0.03) [parasternal long axis view – PLAX view], 25.9 ± 2.3 mm vs 23.5 ± 2.7 mm (p = 0.008) [four chamber view - 4CH view] and larger anterior-posterior mitral annulus diameter 28.1 ± 2.8 mm vs 25.4 ± 3.2 mm (p = 0.011) than those in non-responders group. Among all analysed patients longer anterior mitral leaflet was correlated with lower postoperative LVOT gradient when measured in PLAX view (p = 0.02) and lower degree of MR due to systolic anterior motion (SAM) when measured in 4CH view (p = 0.009). Greater [AML x mitral annulus] ratio correlated with lower postoperative LVOT gradient in both projections: 4CH (p = 0.025), PLAX (p = 0.012). There was significant reduction in NYHA Class after surgery (p = 0.000). There were no significant differences in NYHA class after surgery (p = 0.633) neither in NYHA class reduction (p = 0.475) between patients divided into responders and non-responders group according to echocardiographic parameters.ConclusionsPatients with a longer AML and a greater diameter of the mitral annulus are less likely to have mitral regurgitation due to residual SAM and increased LVOT gradient after an extended myectomy. Division of patients according to echocardiographic criteria into responders and non-responders was not in concordance with clinical improvement.Trial registrationRetrospective study. Approved by ethics committee (IK-NPIA-0021-21/1763/19) at 16.01.2019.

Alcohol septal ablation in hypertrophic obstructive cardiomyopathy: do sex, mitral valve leaflet length and septal thickness affect the outcome?

“…Elongation of the AML and PML (as compared to normal reference range [11]) was observed in most patients in this study, in-line with previous studies of patients HOCM suggesting elongated MV leaflets as being part of the innate HCM phenotype [11,[16][17][18] differences. The finding that BSA-indexed valve leaflet lengths were significantly longer in women in this study, highlight a possible persistent functional difference that need to be further studied.…”

“…Elongation of the AML and PML (as compared to normal reference range [11]) was observed in most patients in this study, in-line with previous studies of patients HOCM suggesting elongated MV leaflets as being part of the innate HCM phenotype [11,16–18]. Although the correlation between MVLL and outcome after ASA has not yet been shown.…”

Left Ventricular Outflow Tract and Transcatheter Mitral Valve Replacement Obstruction and TMVR: Predictors, Evaluation, and Solutions

“…Though well understood to be a contributing factor to outcomes following mitral valve surgery and septal myectomy, understanding how to manage a long or redundant native anterior leaflet in the setting of TMVR is in its early phases. 9 , 10 Reports describe an overhanging anterior leaflet interacting with, or impinging on, the leaflets of the prosthesis, which may lead to dysfunction. More to the topic at hand, a large, billowy native leaflet may result in dynamic outflow obstruction, as may be seen in a patient with hypertrophic cardiomyopathy-type LVOTO in the setting of systolic anterior mitral leaflet motion.…”