Clinical outcomes after transcatheter aortic valve replacement in cancer survivors treated with ionizing radiation

Background: Improved cancer survival in patients treated with thoracic ionizing radiation (XRT) has resulted in unanticipated surge of aortic stenosis. Transcatheter aortic valve replacement (TAVR) has revolutionized the management of severe aortic stenosis. However, long-term clinical outcomes in radiation-exposed cohorts undergoing TAVR are unknown. We compared the all-cause mortality and major adverse cardiac events (MACE) in patients with prior chest XRT (C-XRT) undergoing TAVR. Methods: This is an observational cohort study in subjects who underwent TAVR for symptomatic severe aortic stenosis from 2012 to 2017 in a tertiary care referral center. We examined the all-cause mortality and MACE using cox proportional hazard analysis to identify the clinical predictors of survival in the cohort of patients who had a history of prior C-XRT for malignancy. Results: Of the 610 patients who underwent TAVR for symptomatic severe aortic stenosis, 75 had prior C-XRT. The majority of C-XRT patients had prior breast cancer (44%) followed by Hodgkin's lymphoma (31%), with the median time from XRT to TAVR of 19.0 years. During a mean follow up of 17.1 months after TAVR, all-cause mortality was 17%. Those with prior C-XRT had higher all-cause mortality (XRT: 29%; non-XRT:15%, p < 0.01) and MACE (XRT: 57%; non-XRT: 27%, p < 0.001) after TAVR. Patients with prior XRT had a higher incidence of atrial fibrillation (XRT: 48%; non-XRT: 2.4%, p < 0.01) and high-grade heart block (XRT: 20%; non-XRT: 9.1%, p = 0.007) requiring pacemaker implant after TAVR. On multivariate cox proportional hazard analysis, prior XRT (HR: 2.07, p = 0.003), poor renal function (HR: 1.29, p < 0.001) and post-operative anemia requiring transfusion (HR: 1.16, p:0.001) were the strongest predictors of reduced survival. Conclusions: Cancer survivors with prior C-XRT have higher incidence of all-cause mortality and MACE after TAVR. Careful patient selection and follow-up strategies are needed to improve outcomes.