P1557Different manifestation of radiation induced coronary artery disease detected with coronary computed tomography compared with matched non-irradiated controls

Background: Patients who received chest radiotherapy for treatment of a malignancy are at increased risk for the development of coronary artery disease (CAD) and subsequent ischemic heart disease. Little is known about anatomical characteristics of radiation induced CAD. This study aimed to detect differences in presence, extent, severity, composition and location of CAD in patients treated with mediastinal radiotherapy compared with age, gender and risk factor matched controls. Methods and results: 79 asymptomatic Hodgkin and non-Hodgkin lymphoma survivors, all treated with mediastinal radiotherapy with or without chemotherapy, who underwent routine coronary computed tomography angiography (CTA) to identify CAD were included. Patients were 1:3 matched with non-irradiated controls (N=237) on age, gender, diabetes, hypertension, hypercholesterolemia, family history of CAD and currently smoking. Mean age at cancer diagnosis was 26±9 years and age at coronary CTA was 45±11 years. More patients had an abnormal scan (any coronary plaque): 59% vs. 36%, P<0.001 and showed significantly more two vessel disease: 10% vs 6% and three vessel disease: 24% vs 9% compared with controls. The maximum stenosis severity among patients was less often <30% (53% vs. 68%) and more often >70% (7% vs. 0%), overall P=0.001. Patients had more plaques in proximal coronary segments: left main (17% vs. 6%, P=0.004), proximal left anterior descending artery (30% vs. 16%, P=0.004), proximal right coronary artery (25% vs 10%, P<0.001) and proximal left circumflex (14% vs 6%, P=0.022), but the number of plaques in non-proximal segments did not differ between groups.