Safety and Outcomes of Alcohol Septal Ablation Prior to Transcatheter Mitral Valve Replacement

Background: Patients undergoing transcatheter mitral valve replacement (TMVR) for mitral valve disease caused by severe mitral annular calcification are at risk of left ventricular outflow obstruction. Preemptive alcohol septal ablation (ASA) can potentially mitigate the risk of this complication and is well established in patients with hypertrophic obstructive cardiomyopathy (HCM). Methods: This retrospective study compared procedural characteristics and outcomes in patients who underwent ASA for TMVR vs HCM. Results: In total, 102 patients were included, 22 in the TMVR group and 80 in the HCM group. Echocardiography demonstrated increased septal wall thickness in the HCM group (19 ​± ​3.1 ​mm vs 12.7 ​± ​2.0 ​mm; P ​< ​.001). The mean volume of ethanol injected was higher in the HCM group (1.4 ​± ​0.49 ​mL vs 0.8 ​± ​0.2 ​mL; P ​< ​.001). The average neo–left ventricular outflow tract area increased significantly after ASA in the patients undergoing TMVR (135 ​± ​89 ​mm² vs 233 ​± ​111 ​mm²; P ​< ​.001). Six patients in the TMVR group did not achieve an adequate increase in the neo–left ventricular outflow tract area and required further procedures after ASA. The incidence of post-ASA complete heart block requiring a permanent pacemaker tended to be higher in the TMVR group (35% vs 21%; P ​= ​.195). No patients in either group had ventricular arrhythmia or stroke. Major bleeding complications were 4% in the HCM group and 0 in the TMVR group. The 30-day mortality was 4% in the HCM group and 0 in the TMVR group; however, 1 patient died at 37 ​days in the TMVR group, presumably from late heart block. Conclusions: Preemptive ASA in patients undergoing TMVR demonstrated safety and short-term clinical outcomes similar to patients with HCM.