Abstract 12932: Should We Screen For Radiotherapy-Induced Heart Disease With Exercise Stress Echocardiography? Emphasis on Major Adverse Cardiac Events

Abstract

Introduction: Exercise Stress Echocardiography (ESE) is recommended as a screening tool for the evaluation of Coronary Artery Disease (CAD) in patients with suspected Radiation-Induced Heart Disease (RIHD). Up to now, studies have only evaluated its association with the extent of CAD. Hypothesis Cancer survivors treated with chest Radiotherapy (RT) that undergo an ESE and have a +ESE develop more MACE than those who have -ESE. Methods: A retrospective, descriptive, cohort study was conducted. Patients who had chest RT and underwent ESE with Treadmill Bruce Stress Protocol, from 2000 to 2012, at Mayo Clinic Rochester and Mayo Clinic Health System were included. A univariate analysis was performed to characterize the population. An analysis including Kruskal Wallis and Pearson Chi-Squared tests was completed to identify variables associated with + SE (Table 1). Multivariable Cox Model for MACE was conducted and is shown in Table 2. A time-to-event curve using Kaplan-Meier estimates is shown in Figure 1. Results: We identified 113 patients, with a mean age of 67 years and a median follow-up of 15.1 years. Of those, 99% were female, 98% were breast cancer survivors, 59% had HTN, 14% DM, 11% AFib, 2% COPD, and 12% had a history of MI. All the patients received >3000cGy of Photon RT, and 57% were treated with systemic cancer therapies. A +ESE was seen in 20.3% of the patients with no significant difference in METS achieved compared with patients who had a -ESE. COPD, RT dose, and systemic therapies, specifically doxorubicin, were associated with a +ESE. The cumulative incidence of MACE was higher in the group of +ESE (p=0.029). After adjustment for HTN, DM, smoking history, hyperlipidemia, and prior MI, the HR for MACE associated with a +ESE was 1.97 (1.09-3.59). Conclusion: MACE was more frequent in patients with a +ESE who received chest RT and doxorubicin versus -ESE. These results support the usefulness of ESE in cancer survivors after RT as a cardiovascular screening tool.