Targeting alcohol septal ablation in patients with obstructive hypertrophic cardiomyopathy candidates for surgical myectomy: Added value of three‐dimensional intracoronary myocardial contrast echocardiography

Background: Myocardial contrast two‐dimensional echocardiography (MC‐2DE) is widely used to address alcohol septal ablation (ASA) in obstructive hypertrophic cardiomyopathy (HCM). Owing to its limited cut‐planes, MC‐2DE may inaccurately identify the contrast misplace-ment associated with an unsuccessful or complicated ASA outcome. Objective: The aim of this study was to assess the added value of myocardial contrast three‐dimensional echocardiography (MC‐ 3DE) compared with MC‐2DE to identify the appropriate matching between the target septal zone (TSZ) and coronary artery branch for safe and long‐term effective ASA in HCM patients. Methods: A consecutive series of 52 symptomatic obstructive HCM patients referred for isolated surgical my-ectomy (SM) was analyzed with MC‐2DE and MC‐3DE following injection of echocontrast into one or more septal branches. MC‐2DE and MC‐3DE patterns were categorized according to complete (Type 1) or incomplete (Type 2) TSZ covering, high‐risk (Type 3) exceeding TSZ, or life‐threatening outside TSZ distribution (Type 4). Results: MC‐2DE per patient analysis showed a Type 1 pattern in 32 patients and Types 2–4 in the remaining 20 patients; subsequent MC‐3DE analysis provided a re-phenotyping of MC‐2DE findings in 22 of the 52 patients (42%), showing a high‐risk Type 2 pattern in 17 of the 32 patients with Type 1, and a new life‐threatening Type 4 in three patients with Type 2, respectively. All patients with MC‐3DE Type 1 pattern underwent safe and effective ASA with a long‐term uneventful follow‐up, while the remaining patients underwent SM. Conclusions: Refining high risk or life‐threatening contrast misplacement, MC‐3DE is more accurate than conventional MC‐2DE to target safe and long‐term effective septal reduction with ASA in obstructive HCM patients referred for isolated SM.