Po-05-064 utility of catheter ablation vt risk scores in predicting outcomes following cardiac radioablation for high-risk refractory vt

Cardiac radioablation (CRA) is an emerging treatment for high-risk refractory ventricular tachycardia (VT). Validated risk scores (I-VT, PAINESD) exist for prediction of outcomes following catheter ablation (CA) for VT but have unclear utility in patients undergoing CRA. Examine outcomes for high-risk refractory VT treated with CRA at a high-volume center stratified by I-VT and PAINESD scores. Single-center, IRB-approved retrospective case series of patients with refractory VT who had failed at least one prior CA (or were unfit for CA) treated with CRA. I-VT and PAINESD scores were calculated for each patient. Rates of survival (OS), freedom from shock and/or storm (FFSS), and freedom from death, shock, and/or storm (FFDSS) were collected, and stratified by I-VT and PAINESD score. Formal statistical comparisons were not performed due to limited patient numbers. From 2015-2020, 22 patients were treated with CRA (18 with prior CA, 4 unfit for CA) for high-risk refractory VT. Median age was 64.5 years (range, 49-84), and 90.9% were male. 50% had ICM, with a median NYHA class of 3 (range, 1-4) and median EF of 25% (range, 15-58%). Median follow-up was 31.3 months. 2-year OS was 54.5%, FFSS was 42.4%, and FFDSS was 27.3%. A total of 63.6% and 68.2% had high risk I-VT and PAINESD scores, respectively. I-VT (low vs high) discriminated 2-year OS (75% vs 42.9%), FFSS (Figure 1B, 57.1% vs 34.6%), and FFDSS (37.5% vs. 21.4%). PAINESD (low/moderate vs high) discriminated 2-year OS (71.4% vs 46.7%), but not FFSS (Figure 1B, 42.9% vs 43.1%), or FFDSS (28.6% vs 26.7%). In patients with high-risk refractory VT treated with CRA, I-VT was a promising predictor of survival and VT outcomes while PAINESD only predicted survival. Use of I-VT risk stratification may serve as a useful metric when selecting patients mostly likely to benefit from CRA in future studies and requires validation in a larger cohort.