Alcohol Septal Ablation in Hypertrophic Obstructive Cardiomyopathy: Long-Term Follow-Up of Deformations and Hemodynamics.

Abstract

Background: A detailed evaluation of hemodynamics, supportive morphology, and deformation may help uncover the pathophysiology of hypertrophic obstructive cardiomyopathy (HOCM) and the changes wrought by alcohol septal ablation (ASA).

Purpose: To investigate the global cardiac volume, myocardial deformation, and hemodynamic characteristics before and during long-term follow-up after ASA in patients with HOCM.

Study type: Retrospective.

Subjects: Twenty-three patients (68.1 ± 8.6 years, 21.7% male) with HOCM who underwent MRI before and after ASA.

Field strength/sequence: A 3T, Two-dimensional fast imaging employing steady-state acquisition, inversion recovery-prepared fast gradient echo sequences, and cine and time-resolved three-dimensional cine phase-contrast (4D flow) MRI.

Assessment: Global left ventricular (LV) volume by cine, peak strain, and strain rate by myocardial feature-tracking MRI, and hemodynamic characteristics by 4D flow MRI.

Statistical tests: Paired t-test and Wilcoxon signed-rank test compared normally and nonnormally distributed data, respectively. Chi-squared or Fisher's exact tests were used to compare categorical data, as appropriate. Pearson's or Spearman's correlation coefficient evaluated the correlations. Statistical significance was set at q ≤ 0.10 or p < 0.05.

Results: In LV long-axis images, the global radial strain increased significantly (16.6% ± 5.8% vs. 20.1% ± 6.8%), whereas the global longitudinal strain decreased significantly after ASA (-10.5% ± 3.2% vs. -12.1% ± 3.5%). The diastolic LV anterior vortex area increased significantly after ASA (2256.1 [703.6, 4038.4] vs. 3826.1 [1914.3, 4820.1] mm²). Multiplication of the LV end-diastolic volume index, global circumferential strain, and diastolic radial peak strain rate in LV long-axis images revealed a significant correlation with the diastolic LV anterior vortex area (Rs = 0.43).

Data conclusions: Feature-tracking and 4D flow MRI revealed improved systolic and diastolic LV function during long-term follow-up after ASA. The diastolic LV vortex was associated with the combined parameters of LV volume and deformation. Comprehensive cardiac MRI may help understand the beneficial effects of ASA.

Evidence level: 3.

Technical efficacy: Stage 5.