October 14, 2019
Five-Year STABLE I Results Reported for Cook Medical's Zenith System to Treat Complicated Type B Aortic Dissections
October 15, 2019—The final 5-year results from STABLE I were published by Joseph V. Lombardi, MD, et al in Journal of Vascular Surgery (2019;70:1072–1081).
STABLE I is a prospective, single-arm, multicenter evaluation of the Zenith dissection endovascular system (Cook Medical). The investigators noted that the Zenith is a pathology-specific device composed of a proximal stent graft with barbs and a distal bare stainless-steel stent for the treatment of patients with complicated type B aortic dissection.
In February 2019, Cook announced FDA approval of the device; in March, the company announced its launch in the United States. Dr. Lombardi is the global principal investigator of the STABLE I and STABLE II clinical trials that evaluated the device.
As summarized in Journal of Vascular Surgery, the study prospectively enrolled 86 patients (mean age, 59 years; 73% men) at sites in the United States (STABLE I in United States), Europe, and Australia (STABLE 1 outside the United States) from 2007 to 2012. Treatment occurred during the acute phase (≤ 14 days after symptom onset) in 55 patients and during the nonacute phase (> 14 days; all treated ≤ 90 days) in 31 patients.
At 30 days, the all-cause mortality rate was 5.5% (3/55) for acute patients and 3.2% (1/31) for nonacute patients (P > .99).
In the 5-year clinical and imaging data from STABLE I, which were available for 88.5% of eligible patients, investigators found that the acute and nonacute cohorts appeared to respond similarly to treatment involving use of the stent grafts and bare-metal stents, demonstrating similar clinical outcomes and favorable improvement in aortic remodeling in the thoracic and abdominal aortas.
The specific 5-year findings in acute versus nonacute patients included:
- Freedom from all-cause mortality (79.9% ± 6.2% vs 70.1% ± 8.4%; log-rank test, P = .4)
- Freedom from dissection-related mortality—including deaths of indeterminate relatedness to dissection repair (83.9% ± 5.9% vs 90.1% ± 5.9%; log-rank test, P = .55)
- Complete false lumen thrombosis in the thoracic aorta, which increased over time (74.1% vs 58.8%)
- Overall increase in true lumen diameter from preprocedure and a concomitant decrease in false lumen diameter was seen in both groups of patients at the level of the largest diameter in both the thoracic and abdominal aortas
- Stable or shrinking transaortic diameter in the thoracic aorta (65.5% vs 81.3%)
- Stable or shrinking transaortic diameter in the abdominal aorta (48.3% vs 76.5%)
- Freedom from secondary intervention (65.5% ± 7.5% vs 71.2% ± 9%; log-rank test, P = .71)
Endovascular repair of complicated type B aortic dissection with this composite device design demonstrated low all-cause mortality at 30 days, as well as low dissection-related mortality throughout follow-up, concluded the STABLE I investigators in Journal of Vascular Surgery.