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

Introduction:

Hypertrophic obstructive cardiomyopathy (HOCM) is a progressive myocardial disorder leading to heart muscle thickening, diastolic dysfunction, and relevant left ventricular outflow tract obstruction (LVOT). Treatment options for symptomatic HOCM patients with relevant LVOT obstruction include medical therapy or invasive septal reduction therapy (SRT) such as transcoronary ablation of septal hypertrophy (TASH). The majority of patients experience significant LVOT reduction and symptom relief after TASH. However, long-term follow-up data concerning persistent LVOT gradient reduction and symptom control is lacking. With this retrospective cohort analysis, we aim to investigate the clinical and echocardiographic long-term response after TASH.

Material and Methods:

We included 59 patients (55.9% male, mean age 66.5 ± 12.8 years) undergoing TASH from 1997-2023. We assessed the symptom burden using the New York Heart Association (NYHA) classification at baseline and last available follow-up visit, as well as the Kansas City Cardiomyopathy-12 (KCCQ-12) scores during the last clinical visit. Echocardiographic parameters comprising resting and peak LVOT gradients and left ventricular ejection fraction (LVEF) were evaluated at baseline, within one year after TASH and during the last available clinical visit. Complete clinical response after TASH was defined as a composite of LVOT gradient < 30 mmHg and NYHA class I. 

Results: 

A mean clinical and echocardiographic follow-up of 5.7 ± 4.9 years was available. 22 patients (37.3%) showed no clinical symptoms (NYHA I), and 37 patients were classed as ≥NYHA II (62.7%). KCCQ-12 scores were available in 46 patients with a mean of 64.9 ± 26.8. Resting LVOT gradients improved significantly from 64.0 ±47.5 mmHg before TASH to 25.8 ± 25.5 mmHg (p<0.001) within one year after TASH; a gradient of 15.5+/-23.3 mmHg (p<0.001) was recorded at the last available echocardiographic follow-up. Persistent LVOT gradients < 30 mmHg were seen in 51 patients (86.4%), while 8 patients (13,6%) had elevated LVOT gradients (mean 59.1 ± 32.9mmHg) at the last available follow-up. For all patients a preserved LVEF was recorded at baseline and during all echocardiographic follow-ups. Combining clinical and echocardiographic outcome, complete response was recorded in 20 patients (33.9%).  

Conclusion: 

With this retrospective register analysis, we provide long-term clinical and echocardiographic outcome data of patients treated after TASH. Even though LVOT gradients were persistently and significantly reduced in the majority of patients, a significant number of patients remain clinically symptomatic. This suboptimal clinical outcome might reflect the status of the chronically progressing disorder and need further evaluation in bigger cohorts. Furthermore, these findings suggest the need for systematic clinical and echocardiographic follow-up after TASH.