The evolution of Z stent-based stent-grafts for endovascular aneurysm repair: a life-table analysis of 7.5-year followup

BACKGROUND: The purpose of this study was to analyze the impact of stent-graft design and operator skills on outcomes after endovascular abdominal aortic aneurysm repair.

STUDY DESIGN: One hundred sixty-four patients (mean age 71 years) underwent stent-graft repair. Patients were treated with four different types of stent-graft: first-generation (n = 58) and second-generation (n = 17) Ivancev-Malmö monoiliac stent-grafts (IM I and IM II, respectively) combined with femoral-femoral crossover, Chuter bifurcated stent-graft (n = 15), and the Zenith stent-graft (n = 74). Patients underwent digital subtraction angiography and contrast CT preoperatively and were then followed with CT scans postoperatively. Recently, followup was changed to CT scanning at 1 month and 1 year postoperatively and annually thereafter. Ultrasonographic duplex scanning substitutes in the remaining followup. Changes in aneurysm diameters and occurrence of endoleaks were recorded. Short- and midterm mortality and complications and postoperative secondary interventions were recorded, and life-table analysis for intervention-free stent-graft survival was calculated.

RESULTS: Immediate and late conversions and 30-day mortality were reduced for second- (IM II and Zenith) compared with first-generation stent-grafts (IM I and Chuter). Stent-graft migrations occurred only with the IM I and Chuter stent-grafts. Type I endoleak was significantly more common in first-generation stent-grafts. First-generation stent-grafts required significantly more secondary interventions than second-generation stent-grafts up to 30 months postoperatively.

CONCLUSION: Enhanced stent-graft design has improved the probability of stent-graft success after endovascular abdominal aortic aneurysm repair. Better technical skills and increased use of intraoperative adjunctive procedures may also have contributed to improved results.