Aortic events and relative survival in patients with moderately dilated proximal thoracic aorta

Objectives. This study describes growth, local and remote aortic events, and survival in patients with proximal (root, ascending) aortic diameters just below threshold for operation. Methods. Patients with proximal aortic diameter of 4.5 to 5.4 cm at baseline, were followed with serial computed tomography studies and data collected retrospectively. Aortic growth rate was estimated using mixed effects modelling. Clinical and radiological features associated with outcomes (all-cause death, aortic death, local or remote aortic events (dissection, rupture, intramural hematoma, or intervention)) were assessed with Cox analysis. Survival and freedom from events were estimated using Kaplan-Meier methods. Results. 80 patients underwent 274 CT scans during 265 patient-years. Median proximal aortic growth was 0.2 cm in 3 years. 32 events occurred in 28 patients (35%). Eleven events were local, all elective proximal aortic surgery. Nine events were remote: 5 type B aortic dissections, 3 descending aneurysms undergoing elective repair, and one infrarenal aortic rupture. Twelve patients died, half of type B aortic dissection. Relative survival compared to a matched normal population was 82% (95% confidence limits 55-98%) at 10 years. In Cox analysis, increased descending aortic diameter was an independent predictor of all-cause death (hazard ratio [HR], 1.39) and aortic death (HR 1.96). Conclusions. Descending, but not proximal, aortic growth was predictive of lethal events. The decreased relative survival, the substantial number of remote aortic events and aortic deaths strongly suggest continuous serial CT surveillance of the entire aorta. Other indicators than proximal aortic diameter appear needed to improve management of this patient group.