Alcohol Septal Ablation versus Septal Myectomy Treatment of Obstructive Hypertrophic Cardiomyopathy: A Systematic Review and Meta-Analysis

Abstract

Surgical myectomy (SM) and alcohol septal ablation (ASA) are two invasive therapies for symptomatic patients with hypertrophic obstructive cardiomyopathy (HOCM), despite medical therapy. This meta-analysis aims to compare the efficacy of the two procedures. We searched all electronic databases until February 2020 for clinical trials and cohorts comparing clinical outcomes of ASA and SM treatment of patients with HOCM. The primary endpoint was all-cause mortality, cardiovascular (CV) mortality, sudden cardiac death (SCD), re-intervention, and complications. Secondary endpoints included relief of clinical symptoms and drop of left ventricular outflow tract (LVOT) gradient. Twenty studies (4547 patients; 2 CTs and 18 cohorts) comparing ASA vs. SM with a mean follow-up of 47 ± 28.7 months were included. Long term (8.72 vs. 7.84%, p = 0.42) and short term (1.12 vs. 1.27%, p = 0.93) all-cause mortality, CV mortality (2.48 vs. 3.66%, p = 0.26), SCD (1.78 vs. 0.76%, p = 0.20) and stroke (0.36 vs. 1.01%, p = 0.64) were not different between procedures. ASA was associated with lower peri-procedural complications (5.57 vs. 10.5%, p = 0.04) but higher rate of re-interventions (10.1 vs. 0.27%; p < 0.001) and pacemaker dependency (12.4 vs. 4.31%, p = 0.0004) compared to SM. ASA resulted in less reduction in LVOT gradient (−47.8 vs. −58.4 mmHg, p = 0.01) and less improvement of clinical symptoms compared to SM (New York Heart Association (NYHA) class III/IV, 82.4 vs. 94.5%, p < 0.001, angina 53.2 vs. 84.2%, p = 0.02). Thus, ASA and SM treatment of HOCM carry a similar risk of mortality. Peri-procedural complications are less in alcohol ablation but re-intervention and pacemaker implantations are more common. These results might impact the procedure choice in individual patients, for the best clinical outcome.

Alcohol Septal Ablation: An Option on the Rise in Hypertrophic Obstructive Cardiomyopathy

“…However, compared with SM, septal ablation has been associated with a lower decrease in the LVOT gradient, less improvement in symptoms, higher pacemaker implantation and a higher frequency of reinvention. [ 25 , 37 , 49 ]…”

“…As main findings, Bytyçi et al observed a higher rate of pacemaker implantation, higher rates of reintervention and less improvement of clinical symptoms in ASA compared with SM, but in exchange, ASA patients presented lower periprocedural complications [ 25 ].…”

Targeting Alcohol Septal Ablation in Patients with Obstructive Hypertrophic Cardiomyopathy Candidates for Surgical Myectomy: Added Value of Three-Dimensional Intracoronary Myocardial Contrast Echocardiography

“…Dynamic LV obstruction is associated with an unfavorable clinical course and the risk of sudden death and should be considered a therapeutic target in HCM patients [ 18 , 19 , 20 , 21 ]. In symptomatic patients who are unresponsive to medical therapy, septal reduction, including SM or ASA, may be clinically beneficial [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 22 , 23 , 24 ]. To optimize the septal reduction treatment of obstructive HCM, a careful work-up should address the obstruction mechanisms, exclude the primary causes of mitral regurgitation, and provide an accurate measurement of the thickness of the septum in the TSZ responsible for LV obstruction [ 25 , 26 , 27 ].…”

“…This finding is important when selecting HCM patients undergoing ASA with an expected favorable long-term clinical course. Several meta-analyses report a comparable outcome between SM and ASA [ 3 , 6 , 7 , 47 ]. However, the majority of the studies focus ASA results in high-risk elderly HCM population that may be affected by comorbidities, limiting the clinically beneficial impact of the procedure and long-term arrhythmic burden assessment.…”

“…Alcohol septal ablation (ASA) is regarded as an effective alternative to surgical myectomy (SM) to treat left ventricular (LV) obstruction in patients with symptomatic hypertrophic cardiomyopathy (HCM) [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ]. Successful ASA requires alcohol injection into the coronary branch supplying the septal zone involved in the LV obstruction, the so-called target septal zone (TSZ), to induce an appropriate scar mimicking LV outflow tract SM-reshaping.…”