Clinical and echocardiographic long-term follow-up after transcoronary ablation of septal hypertrophy - a retrospective register analysis

Background Treatment options for symptomatic obstructive hypertrophic cardiomyopathy (oHCM) patients with relevant left ventricular outflow tract (LVOT) obstruction include medical therapy or invasive septal reduction therapy (SRT) such as transcoronary ablation of septal hypertrophy (TASH). After TASH, the majority of patients experience significant LVOT-gradient reduction and symptom relief. While the immediate and short-term benefits of TASH are well-documented, the long-term outcomes including both clinical and echocardiographic outcome are less clear [1, 2]. Purpose With this retrospective cohort analysis, we aim to investigate the clinical and echocardiographic long-term response following TASH. Material and Methods In total, 100 patients (57% male, mean age 66.3±12.5 years) undergoing TASH between 1997 and 2024 with a mean follow-up (FU) of 7.9±5.9 years were included. Symptom burden was evaluated using New York Heart Association (NYHA) classification (at baseline, one-year post-TASH, and last FU visit) and Kansas City Cardiomyopathy-12 (KCCQ-12) scores during the last FU visit. Echocardiographic parameters, including resting and peak LVOT gradients and LVEF, were assessed at baseline, within one year after TASH, and at the last available FU. Complete response after TASH was defined as a composite of all LVOT gradients <30mmHg and NYHA class I. Results At latest FU, 40 patients (40%) showed no clinical symptoms (NYHA I), and 60 patients (60%) reported symptoms according to NYHA class II or higher. KCCQ-12 scores were available in 66 patients with a mean of 55.9±32.0 points. All patients presented with preserved LVEF at baseline, in four cases the LVEF deteriorated over time. Resting and peak LVOT gradients improved significantly from 61.2±45.5 mmHg and 120.2±44.3 mmHg before TASH to 25.6±26.7 mmHg (p<0.001) and 54.7±44.2 mmHg (p<0.001) within one year after TASH and remained stable with 17.4±25.1 mmHg (p<0.001) and 32.0±39.9 mmHg (p<0.001) at the last available echocardiographic FU (Fig. 1). A persistent resting LVOT gradient <30 mmHg was seen in 60 patients (60%), while elevated LVOT gradients (mean 73.8±38.0 mmHg) were depicted in 40 patients (40%) at the last FU visit. Complete response was recorded in 29 patients (29%) (Fig. 2). Conclusion This retrospective register analysis provides comprehensive long-term clinical and echocardiographic outcome data for patients treated with TASH. Despite persistent and significant LVOT gradient reduction in most patients, a considerable proportion remain clinically symptomatic. This suboptimal clinical outcome may reflect the progressive nature of the underlying disorder. Our findings underscore the necessity for systematic clinical and echocardiographic FU after TASH. Furthermore, they highlight the potential need for evaluating novel treatment strategies in such patient cohorts.