SS26. Thrombus Volume Is Associated With Cardiovascular Events and Aneurysm Growth in Patients Who Have Abdominal Aortic Aneurysm

Abstract

The aims of this study were to prospectively assess the association of infra-renal abdominal aortic thrombus volume with cardiovascular events and abdominal aortic aneurysm (AAA) growth. 98 patients with AAAs (median diameter 47.2 mm) underwent computed tomography angiography (CTA). The volume of thrombus in the infra-renal aorta was measured by a previously validated technique. Patients were followed prospectively for a median of 3 (inter-quartile range 2.0-3.6) years and cardiovascular events (nonfatal stroke, nonfatal myocardial infarction, coronary revascularization, amputation and cardiovascular death) recorded. 39 patients underwent repeat CTA a median of 1.5 (inter-quartile range 1.1-3.3) years later. Kaplan-Meier and Cox-proportional analysis were used to examine the association of aortic thrombus with cardiovascular events and average weighted AAA growth. A total of 28 cardiovascular event occurred during follow-up. The incidence of cardiovascular events was 23.4 and 49.2% for patients with small (< median) and large (≥median) volumes of aortic thrombus, respectively, at 4 years (p < 0.05). AAA thrombus volume ≥median was associated with increased cardiovascular events (RR 2.8, 95% CI 1.01- 5.24) independent of other risk factors including initial aortic diameter. In the sub-set of patients with CTA follow-up median annual increase in AAA volume was 5.1cm3 (inter-quartile range 0.8-10.3). Annual abdominal aortic volume change was positively correlated with maximal axial abdominal aortic diameter (r = 0.44, p = 0.006) and thrombus volume (r = 0.50, p = 0.001). Thrombus volume ≥median was associated with rapid volumetric growth (≥5 cm3/year), independent of initial aortic diameter (OR 15.0, 95% CI 1.9-115.7, p = 0.009). AAA thrombus volume was independently associated with cardiovascular events and AAA progression. The mechanisms underlying these associations warrant further study in order to determine if anti-thrombotic therapies reduce outcome events.