Results from the Study to Assess Outcomes After Endovascular Repair for Multiple Thoracic Aortic Diseases (SUMMIT)

Abstract

Objective: Thoracic endovascular aortic repair (TEVAR) is currently the treatment of choice for most diseases of the descending thoracic aorta. Using data from the Study to Assess Outcomes After Endovascular Repair for Multiple Thoracic Aortic Diseases (SUMMIT) study we investigated the outcomes of TEVAR for different aortic diseases and risk factors associated with the outcomes.

Methods: The SUMMIT study included aggregated data of 521 TEVAR patients from five Cook-sponsored multicenter trials evaluating thoracic endografts of the Zenith platform (William Cook Europe, ApS, Bjaeverskov, Denmark). In this post hoc analysis, primary outcomes include 30-day and 1-year mortality and morbidity and cumulative mortality and reinterventions. Cox regression analyses were performed to identify risk factors for mortality and reinterventions.

Results: Of the 521 patients (67% male; mean age, 67.2 ± 15 years), 329 were treated for thoracic aortic aneurysms, 56 for thoracic ulcers, 55 for acute and 31 for nonacute type B aortic dissections (TBADs), and 50 for blunt thoracic aortic injuries. The overall 30-day mortality rate was 1.7%, with perioperative stroke occurring in 3.1%, paraplegia in 1.2%, and proximal type I endoleak in 0.4% of patients within 30 days. At 1 year, the cumulative rate was 8.1% for all-cause mortality, 4.0% for stroke, 1.2% for paraplegia, 0.8% for proximal type I endoleak, and 6.0% for secondary interventions. Multivariate analysis showed that significant predictors for all-cause mortality included age (hazard ratio [HR], 1.04 for each additional year), congestive heart failure (HR, 2.87), serum creatinine (HR, 1.19 per 1 mg/dL), iliac tortuosity (HR, 1.32), blood transfusion (HR, 1.59 per 500 mL of packed red blood cells), and occurrence of 30-day stroke (HR, 3.93), paraplegia (HR, 7.79), or paraparesis (HR, 2.46). Patients treated for dissection, but not for thoracic aortic aneurysm or blunt thoracic aortic injury, demonstrated significantly higher risk for reintervention (HR, 5.65 for acute and 6.60 for nonacute TBADs) compared with patients treated for thoracic ulcers (reference group). Intraoperative contrast material (HR, 1.31 per 100 mL) and blood transfusion volumes (HR, 1.42 per 500 mL of packed red blood cells), surrogates of case complexity, were also significant predictors for reintervention.

Conclusions: The results from the SUMMIT study demonstrated exceptionally low mortality and stroke rates at 30 days and low aortic disease-related mortality during follow-up. TBAD is associated with a higher risk for reintervention, possibly attributed to the natural history of the disease, whereas age, reduced cardiac and renal functions, difficult iliac access anatomy, intraoperative transfusion, and early neurologic complications are associated with higher risk for cumulative all-cause mortality.

Keywords: Aortic aneurysm; Aortic dissection; Thoracic aortic pathology; Thoracic endovascular aortic repair.