Five-year results of the STABLE II study for the endovascular treatment of complicated, acute type B aortic dissection with a composite device design.

Objective: To provide the 5-year outcomes of the use of a composite device (proximal covered stent graft + distal bare stent) for endovascular repair of patients with acute, type B aortic dissection complicated by aortic rupture and/or malperfusion.

Methods: Study of Thoracic Aortic Type B Dissection Using Endoluminal Repair (STABLE) II was a prospective, multicenter study of the Zenith Dissection Endovascular System (William Cook Europe). Patients were enrolled between August 2012 and January 2015 at sites in the United States and Japan. Five-year follow-up was completed by January 2020.

Results: In total, 73 patients (mean age: 60.7 ± 10.9 years; 65.8% male) with acute type B dissection complicated by malperfusion (72.6%), rupture (21.9%), or both (5.5%) were enrolled. Patients were treated with either a composite device (79.5%) or the proximal stent graft alone (no distal bare stent, 20.5%). Dissections were more extensive in patients who received the composite device (408.9 ± 121.3 mm) than in patients who did not receive a bare stent (315.9 ± 100.1 mm). The mean follow-up was 1209.4 ± 754.6 days. Freedom from all-cause mortality was 80.3% ± 4.7% at 1 year and 68.9% ± 7.3% at 5 years. Freedom from dissection-related mortality remained at 97.1% ± 2.1% from 1-year through 5-year follow-up. Within the stent-graft region, the rate of either complete thrombosis or elimination of the false lumen increased over time (82.1% of all patients at 5 years vs 55.7% at first postprocedure computed tomography), with a higher rate at 5 years in patients who received the composite device (90.5%) compared with patients without the bare stent (57.1%). Throughout the follow-up, overall true lumen diameter increased within the stent-graft region, and overall false lumen diameter decreased. At 5 years, 20.7% of patients experienced a decrease in maximum transaortic diameter within the stent-graft region, 17.2% experienced an increase, and 62.1% experienced no change. Distal to the treated segment (but within the dissected aorta), 23.1% of patients experience no change in transaortic diameter at 5 years; a bare stent was deployed in all these patients at the procedure. Five-year freedom from all secondary intervention was 70.7% ± 7.2%.

Conclusions: These 5-year outcomes indicate a low rate of dissection-related mortality for the Zenith Dissection Endovascular System in the treatment of patients with acute, complicated type B aortic dissection. Further, these data suggest a positive influence of composite device use on false lumen thrombosis. Continuous monitoring for distal aortic growth is necessary in all patients.