Results of an aortic endograft trial: impact of device failure beyond 12 months

Abstract

Purpose: Analysis endpoints of patient survival and aortic rupture at a reporting interval of 12 months are regularly used to compare endograft aortic aneurysm (EAG) repair to conventional open surgical (COS) repair. This study reports a multicenter EAG repair versus COS repair parallel cohort trial at 12 months and additional observations of specific device failure types and their impact on an aortic endograft design beyond that follow-up period.

Methods: From August 1997 to September 1998, 240 patients who were treated with bifurcation EAG repairs and 28 patients who were treated with straight EAG repairs were compared with 98 patients who were treated with COS repair for elective infrarenal aortic aneurysm repair. Allocation to treatment was based on aneurysm anatomy. All cohorts underwent infrarenal procedures. Data from concurrent, nonrandomized patient accrual from 17 United States institutions were prospectively gathered and independently adjudicated for safety and efficacy. An independent core laboratory evaluated all imaging data.

Results: There were 308 men and 58 women (mean age, 72 years; range, 42-94 years) treated for infrarenal aortic aneurysm (mean diameter, 55 mm; range, 40-115 mm). Mean preoperative aneurysm diameters were clinically similar (EAG repair, 54 mm vs COS repair, 57 mm). The two cohorts were not significantly different in terms of gender (P = .30) or age (P = .32). EAG repair technical success (aneurysm exclusion, graft patency, patient survival) at 30 days was 89.2%. Five patients required immediate conversion to COS repair, four caused by access complications and one caused by operator-induced EAG repair malposition. The 30-day mortality rate was 1.5% for EAG repair and 3.1% for COS repair (P = .59). The 12-month survival rate was 94.3% for EAG repair and 95.9% for COS repair. The intermediate-term cumulative survival rate at 24 months was 84.9% for EAG repair and 80.3% for COS repair (P = .48). EAG repair device failure occurred from fabric erosion in six patients, with two deaths from ruptured aneurysm at 18 and 28 months after endografting and four device failures resolved by secondary procedures. Five endograft limb dislocations were all resolved by secondary endovascular procedures. Major or minor endograft migration required secondary procedures in five patients, including conversion in two patients.

Conclusion: The clinical outcome at 12 months demonstrated effective aneurysm treatment and comparable safety between EAG repair and COS repair by conventional endpoints. Ongoing follow-up beyond 12 months revealed device-related adverse events that required endograft design changes. Diligent surveillance of outcomes beyond 12 months is necessary to adequately evaluate EAG repair devices.