Evaluation of Patient Selection Guidelines for Endoluminal AAA Repair with the Zenith Stent-Graft: The Australasian Experience

Abstract

Purpose: To review the patient selection guidelines for endovascular repair of abdominal aortic aneurysms (AAA) using the Zenith Endovascular Graft and establish an order of importance for each criterion. Methods: The Zenith Endovascular Graft Research Database was interrogated for information on 238 patients (209 men; mean age 74.9 ± 0.9 years, range 50–94) treated with a Zenith bifurcated graft from 1994 to 1998. The common complications of endoluminal AAA repair (endoleak, migration, graft occlusion, graft kinking, conversion, and deployment failure) were analyzed to determine any associations with selection criteria. Results: By 1998, 69% of endograft patients did not meet the recommended guidelines; however, primary and secondary aneurysm exclusion rates were 87% and 94%, respectively. Over a median follow-up of 13.4 months (interquartile range 2.8–24.0), 38 (16%) patients developed 28 (74%) early and 10 (26%) late type-I endoleaks. The endoleak rate in necks ≤10 mm long was 57% (8/14). Endoleak was associated with a neck contour change >3 mm (p = 0.003) and neck length <20 mm (p = 0.045). The risk of proximal endoleak was 4 times greater if at least one of the proximal neck guidelines was breached; combined guideline deviations of “contour change and large diameter” (p = 0.0004), “contour change and short length” (p = 0.006), “large diameter and short length” (p = 0.01), and “contour change and angle” (p = 0.03) also increased the risk of endoleak. Endograft migration was seen in 10 (4.2%) cases; only neck diameter >28 mm (p = 0.0024) was associated with this complication. Conclusions: Proximal neck contour, length, and diameter are the most important criteria in terms of endoleak development. Breaching the proximal neck length criterion resulted in a 4-fold increase in endoleak, and combined deviations from the guidelines multiplied the effect. Necks ≤10 mm long are unsuitable for the standard Zenith graft.