Short- and long-term outcomes of alcohol septal ablation for hypertrophic obstructive cardiomyopathy in patients with mild left ventricular hypertrophy: a propensity score matching analysis

Abstract

Aims Based on European guidelines, alcohol septal ablation (ASA) for hypertrophic obstructive cardiomyopathy (HOCM) is indicated only in patients with interventricular septum (IVS) thickness >16 mm. The aim of this study was to evaluate the short- and long-term outcomes in ASA patients with mild hypertrophy (IVS ≤ 16 mm). Methods and results We retrospectively evaluated 1505 consecutive ASA patients and used propensity score to match 172 pairs (344 patients) in groups IVS ≤ 16 mm or IVS > 16 mm. There was no occurrence of post-ASA ventriculoseptal defect in the whole cohort (n = 1505). Matched patients had 30-day mortality rate 0% in IVS ≤ 16 mm group and 0.6% in IVS > 16 mm group (P = 1). Patients in IVS ≤ 16 mm group had more ASA-attributable early complications (16% vs. 9%; P = 0.049), which was driven by higher need for pacemaker implantation (13% vs. 8%; P = 0.22). The mean follow-up was 5.4 ± 4.3 years and the annual all-cause mortality rate was 1.8 and 3.2 deaths per 100-patient-years in IVS ≤ 16 group and IVS > 16 group, respectively (log-rank test P = 0.04). There were no differences in symptom relief and left ventricular (LV) gradient reduction. Patients with IVS ≤ 16 mm had less repeated septal reduction procedures (log-rank test P = 0.03). Conclusion Selected patients with HOCM and mild hypertrophy (IVS ≤ 16 mm) had more early post-ASA complications driven by need for pacemaker implantation, but their long-term survival is better than in patients with IVS >16 mm. While relief of symptoms and LV obstruction reduction is similar in both groups, a need for repeat septal reduction is higher in patients with IVS > 16 mm.

Hypertrophic cardiomyopathy: the future of treatment

“…Moreover, outcomes have been substantially less impressive outside of experienced centres, with an overall mortality of 5.2% in a nationally representative US database . ASA can have similar efficacy to myectomy, and may potentially be effective even for patients with minimal septal hypertrophy . Procedural mortality from ASA is ∼1%; however, it is associated with a 10–15% rate of complete heart block (CHB), repeat procedures, and a possible increased risk of scar‐related ventricular arrhythmias .…”

“…70 ASA can have similar efficacy to myectomy, and may potentially be effective even for patients with minimal septal hypertrophy. 71 Procedural mortality from ASA is ∼1%; however, it is associated with a 10-15% rate of complete heart block (CHB), repeat procedures, and a possible increased risk of scar-related ventricular arrhythmias. 72,73 Moreover, ASA is dependent on coronary anatomy and, in one study, 15% of patients had unsuitable septal perforators.…”

Ten Tips and Tricks for Performing Alcohol Septal Ablation in Patients with Hypertrophic Obstructive Cardiomyopathy

“…It has been generally accepted that patients selected for ASA should be severely symptomatic and refractory to a medical therapy. [1][2][3] Some studies have suggested a positive prognostic outcome of septal reduction therapy (myectomy or ASA) when LVOT obstruction was eliminated. 6 Additionally, experienced centers have demonstrated a very low procedure-related mortality rate.…”

“…It has been recently demonstrated that in selected patients, with both the modest septum thickness (15-16 mm) and with severe septal hypertrophy, ASA was found effective and safe in the long-term follow-up. 1,7 LVOT obstruction depends largely on the length of mitral leaflets and submitral chords, papillary muscle abnormalities including their number, hypertrophy, localization, and possible direct attachment to anterior mitral leaflet or short interposition of chords. Evidence suggests some patients encounter obstruction not only in LVOT but also in the midventricular part, therefore the precise evaluation of obstruction is necessary, and adding magnetic resonance imaging or computer tomography of a heart is very valuable.…”

“…ASA is described as an interventional procedure guided by myocardial contrast echocardiography and the first septal branch is considered as the usual target of alcohol injection. 1,[4][5][6][7][8] The morphological result of ASA should be similar to myectomy which is difficult to achieve in all patients because of anatomical variations of septal branches. A preprocedural computerized tomography coronary angiography could benefit in identifying the optimal septal (sub)branch.…”