Mitral Valve Abnormalities as Predictors of Procedural Success in Alcohol Septal Ablation: A Pilot Study.

Background/

Objectives

Alcohol septal ablation (ASA) is an established interventional therapy for patients with obstructive hypertrophic cardiomyopathy (OHCM) who remain symptomatic despite optimal medical treatment. Nevertheless, 10-20% of patients fail to achieve a satisfactory hemodynamic or clinical response, highlighting the need for improved patient selection. Given that mitral valve (MV) morphology plays a central role in left ventricular outflow tract (LVOT) obstruction, we aimed to evaluate the impact of MV anatomical parameters on ASA outcomes.

Methods

We retrospectively analyzed 38 OHCM patients who underwent ASA and had complete echocardiographic data before and at 6-month follow-up. Patients were stratified into responders (n = 32, defined as >50% reduction in LVOT pressure gradient and/or residual LVOT gradient < 50 mmHg) and non-responders (n = 6, <50% reduction or persistent gradient ≥ 50 mmHg), consistent with criteria used in previous ASA outcome studies. MV parameters-including redundant anterior mitral leaflet (AML) length, posterior mitral leaflet (PML) projection, and anterior displacement of the coaptation point (AML/PML projection ratio)-were compared between groups.

Results

Non-responders demonstrated significantly greater AML redundancy (13.16 ± 1.72 vs. 9.96 ± 1.99 mm, p < 0.001), larger PML projection (18.5 ± 3.78 vs. 13.65 ± 3.8 mm, p = 0.006), and lower AML/PML projection ratio (0.80 ± 0.15 vs. 1.34 ± 0.45, p = 0.007). These parameters were associated with reduced post-procedural LVOT gradient reduction in univariate logistic regression (p = 0.01, p = 0.027, p = 0.015, respectively). Multivariate modeling was not pursued due to collinearity among MV parameters and the limited number of non-responder events, which precluded robust adjustment.

Conclusions

Mitral valve morphological features-particularly redundant AML, greater PML projection, and anterior displacement of the coaptation point-were associated with suboptimal ASA outcomes in univariate analysis. These data emphasize the need for comprehensive MV imaging in pre-procedural assessment. Integrating MV morphology into current selection algorithms may refine ASA patient selection and improve long-term success rates.