Supplementary Material for: Predictive Value of Existing Prediction Models for Short-term Outcomes after Percutaneous Intramyocardial Septal Radiofrequency Ablation

Backgrounds: Percutaneous IntraMyocardial Septal Radiofrequency Ablation (PIMSRA, Liwen procedure) is a novel septal reduction therapy (SRT) for drug-refractory hypertrophic obstructive cardiomyopathy (HOCM) patients. Due to the lack of SRT risk tools, EuroSCORE-Ⅱ, STS-PROM and HCM Risk-SCD have been considered as potential alternatives for risk assessment prior to SRT. We aim to evaluate the predictive value of these models for short-term adverse events in HOCM patients undergoing PIMSRA.
Methods: A total of 571 HOCM patients treated with PIMSRA in Xijing Hospital from October 2016 to June 2024 were retrospectively enrolled and their risk scores were calculated. The primary outcome was the 30-day incidence of major adverse cardiovascular events (MACE), including a composite of all-cause death, cardiac tamponade, arrhythmic events, cardiogenic shock and stroke.
Results: During the 30-day follow-up, 61 (10.7%) patients experienced MACE. Multivariate analysis revealed that EuroSCORE-Ⅱ (OR = 2.30), STS-PROM (OR= 1.18), history of syncope and peak left ventricular outflow tract (LVOT) gradient were independently associated with MACE risk after PIMSRA. The area under the receiver operating-characteristic curve (AUROC) values were 0.657 (95% CI: 0.581-0.733) for EuroSCORE-Ⅱ, 0.623 (95% CI: 0.551-0.696) for STS-PROM, and 0.550 (95% CI: 0.469-0.631) for HCM Risk-SCD. Calibration metrics for three models were favorable because of the low incidence of MACE. DCA showed limited benefit to using any score.
Conclusions: EuroSCORE-Ⅱ, STS-PROM, history of syncope and peak LVOT gradient were independently associated with increased risk of 30-day MACE following PIMSRA. Developing SRT-specific risk prediction models is essential for optimizing SRT risk assessment.