Background: Several studies indicate safety and efficacy of alcohol septal ablation (ASA) for the treatment of hypertrophic obstructive cardiomyopathy (HOCM). However, patients with advanced age ≥75 years have not been adequately represented in these studies. 

Methods and Results: All consecutive ASAs, which were performed at our institution between 1997 and 2021, were allocated to a group of patients ≥75 years (n=208; group A) and to a group <75 years (n=1,430; group B). At baseline group A patients had more often female sex (85.1% vs. 42.0%; p<0.0001) and coronary artery disease (21.3% vs. 12.2%; p=0.0004), lower distances in 6MWT (317.0m [IQR 242.0-389.0] vs. 438.0m [IQR 353.3-504.0]; p<0.0001) and more severe symptoms (NYHA 2.96±0.60 vs. 2.65±0.69; p<0.0001).

The exercise-induced LVOTG at baseline was 123.0mmHg (IQR 86.0-160.0) in group A vs. 110.0mmHg (IQR 69.0-150.0) in group B (p=0.0050) but this was not statistically significant after application of Bonferroni correction. At mid-term follow-up (FU) 6 months after ASA exercise-induced LVOTG was lower in group A (29.5mmHg [IQR 18.0-54.0] vs. 39.5mmHg [IQR 23.0-73.8]; p=0.0007; Figure 1). There were no differences with regard to the improvement of exercise-induced LVOTG from baseline to FU (group A: 58.0mmHg IQR 27.5-106.0]; group B: 67.0mmHg [30.0-103.0]; p=n.s.). 

NYHA class significantly improved in both groups (p<0.0001). The distance walked in 6MWT at FU was lower in group A (370.5m [288.3-440.8] vs. 511.0m [440.0-590.8]; p<0.0001). The improvement in 6MWT was not statistically different after Bonferroni correction (24.0m [IQR -8.5-94.5] in group A vs. 76.0m [25.0-131.0] in group B; p=0.0013). More group A patients (25.5 %) developed persistent AV block after ASA (vs. 13.6 %; p<0.0001; Figure 2). Thus, more group A patients (24.0 %) needed a PM after ASA (vs. 11.0; p<0.0001; Table 4). There were no differences regarding intrahospital mortality (group A: 1.0 %; group B: 0.6 %; p=n.s.) or mortality during FU (group A: 1.5 %; group B: 0.5 %; p=n.s.).

Conclusion: ASA was safe and effective even in patients with more advance age ≥75 years despite more severe symptoms and lower distances walked in 6MWT at baseline. Elderly patients had lower exercise-induced LVOTG at FU but the extent of improvement was not different compared to patients <75years. Thus, ASA should be considered even for elderly patients with symptomatic HOCM despite drug therapy.

Figure 1 Exercise-induced LVOTG (in mmHg) calculated using CW-doppler in patients ≥ 75 and < 75 years of age at baseline and at mid-term FU 6 months after ASA. * = p<0.0011. n.s. = not significant after application of Bonferroni correction to adjust for multiple testing.

Figure 2 Incidence of persistent AV block after ASA in patients ≥ 75 and < 75 years of age. * = p<0.0011.