Abstract 14945: Prognostic Value of Cardiac 123 I-MIBG Imaging for Predicting Cardiac Events After Transcatheter Aortic Valve Replacement

Abstract

Introduction: In patients with aortic valve stenosis (AS), cardiac sympathetic nervous (CSN) dysfunction and its improvement after transcatheter aortic valve replacement (TAVR) have been reported; however, the prognostic impact of CSN function remains unclear. This study investigated the prognostic value of cardiac 123 I-metaiodobenzylguanidine (MIBG) imaging for predicting cardiac events after TAVR. Hypothesis: We hypothesized that the improvement in MIBG parameter with TAVR treatment can be an indicator of better prognosis. Methods: This single-center prospective observational study enrolled patients with AS between July 2017 and May 2019. MIBG scintigraphy was performed before and after TAVR to evaluate the delayed heart-mediastinum ratio (d-H/M). Patients were classified into three pairs of groups based on the baseline and post-TAVR d-H/M (≥2.0 or <2.0) and on the presence of TAVR-related improvement in d-H/M (i.e. Δ d-H/M [post-TAVR – baseline] >0 or ≤0). The study endpoint was the occurrence of major adverse cardiac events (MACE), defined as a composite of all-cause death, non-fatal myocardial infarction, and hospitalization due to heart failure. Results: Among the 187 consecutive patients who underwent TAVR, 107 (27 men; median age: 86 years) were evaluated. Over a median follow-up of 366 days, 15 (14.0%) patients had MACE. The incidence of MACE was significantly low in patients with d-H/M improvement and/or high post-TAVR d-H/M (≥2.0). Baseline d-H/M and frailty were associated with poor response of d-H/M to TAVR treatment. Moreover, post-TAVR d-H/M had significant effects on MACE, with an adjusted hazard ratio of 1.264 (95% confidence interval, 0.034-2.480; p=0.04). Conclusions: Both d-H/M improvement and high post-TAVR d-H/M were associated with better prognosis in patients who underwent TAVR. Cardiac MIBG imaging is useful for predicting cardiac events after TAVR.