STABLE II clinical trial on endovascular treatment of acute, complicated type B aortic dissection with a composite device design

Objective: To evaluate the safety and effectiveness of a composite device design (covered stent graft and bare metal stent) for the treatment of patients with acute, complicated type B aortic dissection (TBAD) presenting with aortic rupture and/or branch vessel malperfusion. Methods: In this prospective, nonrandomized, multicenter study, 73 patients (65.8% male; mean age, 60.7 years) with acute, complicated TBAD were enrolled between August 2012 and January 2015 to receive treatment with the Zenith Dissection Endovascular System (William Cook Europe, Aps, Bjaeverskov, Denmark) at institutions in the United States and Japan. The primary safety end point was the rate of freedom from major adverse events at 30 days, and the primary effectiveness end point was the rate of survival at 30 days. This article reports primary outcomes at 30 days and follow-up results through 1 year, reflecting study data as of March 2018. Results: Of 73 patients, 20 presented with aortic rupture (27%) and 57 presented with branch vessel obstruction/compromise (78%), including 4 patients presenting with both conditions. The covered stent graft was used in all patients (median, 1; range, 13; 1 stent graft used in 64.4%; 47/73), and the bare metal dissection stent was used in 58 of 73 patients (79.5%). Thirty-day mortality occurred in five patients (6.8%): one procedure related, three unrelated to dissection repair, and one indeterminate. Thirty-day major adverse events included myocardial infarction (1.4%), bowel ischemia (1.4%), renal insufficiency/renal failure requiring dialysis (6.8%), stroke (6.8%), paraplegia or paraparesis (5.5%), and prolonged ventilatory support (13.7%). Nine deaths occurred from 31 to 365 days (only one death related to dissection repair); the Kaplan-Meier estimate of freedom from all-cause mortality was 80.3% +/- 4.7% at 1 year. Within 365 days, 9 of 73 patients (12.3%) underwent 10 secondary interventions; nopatients required conversion to open surgery. At the 12-month follow-up, complete or partial thrombosis of the false lumen was seen in 100% of patients (46/46) within the stent graft region and in 97.4% of patients (38/39) within the dissection stent region. Growth(>5mm) of the maximum transaortic diameter was observed in 14.9% of patients (7/47) in the stent graft region and in 38.5% of patients (15/39) within the dissection stent region at 12 months. Conclusions: Thirty-day and 1-year results from the STABLE II study demonstrated favorable clinical and anatomical outcomes for the treatment of rupture and malperfusion in the setting of acute, complicated TBAD. Five-year follow-up is ongoing.