A prospective randomized comparison of contralateral snare versus retrograde gate cannulation in endovascular aneurysm repair

Abstract

Objective: The objective of this study was to compare snare vs the standard retrograde gate cannulation method during endovascular aneurysm repair to determine the most efficient technique and to evaluate whether time was affected by graft design or the surgeon's experience.

Methods: This was a prospective randomized study involving single-center elective endovascular aneurysm repairs. Patients were randomized to the snare or retrograde group in a 1:1 ratio. The initial method was attempted for 15 minutes; if it was unsuccessful, the team switched to the alternative technique for an additional 15 minutes. The protocol continued until success was achieved. Data collected on demographic, anatomic, and procedural factors were analyzed for statistically significant differences.

Results: A total of 101 patients were included. Average age was 75.3 years, and 82% were male; 49 patients were randomized to snare and 52 to retrograde cannulation. The groups were overall similar. Median cannulation times were 3.9 minutes for the snare and 2.7 minutes for the retrograde technique (P = .13). The snare group attempts were successful within the initial 15-minute period in all but one patient (98% success). In the retrograde group, 5 of the 52 (10%) crossed over to snare. This difference did not reach statistical significance (P = .11). A difference was seen in the extremes of cannulation times. The surgeon's experience and graft design were not found to have significant effects on cannulation times. Further analysis of the retrograde group patients with long cannulation time found a relative breakpoint at the 5-minute mark. In those exceeding this time mark, the chance of eventual cannulation within 15 minutes dropped to 67%. In this group, median time to cannulation was 12.2 minutes for retrograde compared with 7.1 minutes for snare after crossover.

Conclusions: Gate cannulation was successful using both methods with no statistical difference between the two in median time. Retrograde cannulation was found to be more likely to have short times. If cannulation by retrograde technique had not been achieved in the first 5 minutes, the chances of eventual success dropped significantly, and crossover to snare was more efficient. This finding suggests that one should consider an alternative method of gate cannulation if it has not been accomplished within this time.