Despite substantial anatomic differences between men and women, endovascular repair (EVAR) of abdominal aortic aneurysm yields similar outcomes irrespective of patient sex, according to a registry study published online December 26, 2012, ahead of print in the Journal of Vascular Surgery.

The ENGAGE registry study, led by Thomas L. Forbes, of the London Health Sciences Centre (London, Canada), included 1,131 men and 131 women treated electively for infrarenal aneurysm with the Endurant stent graft (Medtronic, Minneapolis, MN).

Echoing the findings of earlier research, female patients were older and had more complex anatomy than their male counterparts. Yet there were no major differences in outcome in men and women with regard to endoleak, technical success, major adverse events (all-cause mortality, bowel ischemia, MI, paraplegia, renal failure, respiratory failure, and stroke), or mortality (table 1).

Table 1. Clinical Outcomes After EVAR

Abbreviation: MAE, major adverse events.

No patients suffered AAA rupture. There were also no sex differences in terms of stent graft kinking or occlusion, or in the need to convert to open surgery. After 1 year of follow-up, overall survival was 92.5% in men and 91.6% in women (P = 0.99).

Findings May Be Flawed

In an e-mail communication, Frank A. Lederle, MD, of the Veterans Affairs Medical Center (Minneapolis, MN), told TCTMD that the new study may be too small to counter previous suggestions that women have poorer outcomes than men after EVAR.

Dr. Lederle cited a large observational study published several years ago in the Journal of Vascular Surgery (McPhee JT. J Vasc Surg. 2007;45:891-899). That analysis showed women to have an in-hospital mortality rate more than double that of men (2.1% vs. 0.83%; P < 0.0001). Notably, it included nearly 40,000 women with intact AAA, compared to the current cohort of 131.

“So yes, we would need a larger study to accept [the current] finding,” Dr. Lederle said. He also noted that patient selection criteria could have influenced the outcome, whereas the earlier study included all patients in the United States who underwent repair.

The investigators acknowledge a number of study limitations. The ENGAGE registry was not prospectively powered to assess sex differences, and outcomes were reported by treating surgeons, which could introduce some bias. When comparing this study with previous results, they caution, it is important to remember that the “influence of the Endurant stent graft is difficult to separate from such advances as improvements in imaging and increased operator experience.”

Finally, the “report represents short-term outcomes, some of which differed between sexes, but did not reach statistical significance, possibly representing a type II error, ” Dr. Forbes and colleagues conclude. “Long-term outcomes are necessary to further clarify many of these issues.”

Study Details

There were numerous anatomical differences between men and women. Men had larger aneurysms than women at 60.6 ± 11.9 mm vs. 57.8 ± 9.5 mm (P = 0.01). Infrarenal proximal aortic neck diameter was longer in men (24.0 ± 3.5 mm vs. 21.8 ± 3.4 mm; P < 0.001), as was the aortic neck (27.3 ± 12.4 mm vs. 24.3 ± 11.8 mm; P < 0.001). The diameters of both the right and left common iliac arteries were larger in men, who also had a more acute infrarenal aortic neck angle (29.4 ± 23.3° vs. 37.7 ± 26.2°; P < 0.001). Nearly a fifth of women had a neck angle greater than 60°, compared with 9.1% of men (P = 0.001).

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