Background: Data on gender-related differences regarding procedure-related aspects and outcome in hypertrophic obstructive cardiomyopathy (HOCM) patients undergoing alcohol septal ablation (ASA) are scarce. 

Methods and Results: We retrospectively analyzed 1,367 consecutive ASAs between 2002 and 2020 at our institution for gender disparities (47.2% female). Women were older at the timing of ASA (62.8±14.4 vs. 52.8±13.2 years in men; p<0.0001), had a higher degree of symptoms according to the NYHA class (2.8±0.6 vs. 2.5±0.8 in men; p<0.0001) and shorter distances walked in 6-min-walk-test at baseline (357.7±119.9 vs. 457.8±102.3m in men; p<0.0001). Men had higher interventricular septal diameters (IVSD) at baseline (22.0±4.7 vs. 20.7±4.3mm in women; p<0.0001). However, the IVSD was higher in women when it was indexed to the body-surface-area (11.3±2.6 vs. 10.6±2.5mm/m² in men; p<0.0001). Immediately after ASA the resting and exercise-induced left ventricular outflow tract gradients (LVOTG) were lower in female patients (resting: 30.6±29.7 vs. 32.3±27.4 mmHg in male patients; p=0.0062; exercise-induced: 72.5±52.5 vs. 80.5±50.5mmHg in male patients; p=0.0006). At follow-up after 6 months women had lower exercise-induced LVOTG (53.3±45.3 vs. 56.8±42.6mmHg in men; p=0.0072) but not lower resting LVOTG (22.0±22.6 in women vs. 22.5±20.5mmHg in men; p=n.s.). Persistent high-degree AV block after ASA was more often found in women (20.3% vs. 13.3% in men; p=0.0005) and, thus, more women (17.4%) than men (10.4%; p=0.0002) required a PM after ASA. Mortality was not different between the groups.

Conclusion: Women treated with ASA for HOCM were older, had more severe symptoms and a higher IVSD when indexed to BSA at the timing of the procedure. Nevertheless, immediate hemodynamic response was better in female patients after ASA while women more often experienced procedure-related high-degree AV block. Sex-related differences in clinical characteristics and procedural outcome of ASA should be taken into consideration.

Figure 1 Baseline absolute interventricular septum diameter (IVSD) in female and male patients treated with ASA. ****=p<0.0001. 

Figure 2 Baseline interventricular septum diameter (IVSD) indexed to body-surface-area using the Mosteller formular in female and male patients treated with ASA. ****=p<0.0001. 

Figure 3 Course of exercise-induced left ventricular outflow tract gradient (LVOTG) calculated at baseline, at short-term follow-up (FU) immediately after ASA and at long-term FU after 6 months. ***=p<0.001. **=p<0.01.