WVS 2022: Study probes who benefits from EVAR among patients with chronic kidney disease

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Mitri Khoury

Patients with advanced chronic kidney disease (CKD) represent a high-risk group who may not benefit from elective endovascular aneurysm repair (EVAR) for abdominal aortic aneurysms (AAAs) under traditional sizing criteria. 

That was among the chief findings in a paper presented by Mitri Khoury, MD, who recently completed his residency at the University of Texas Southwestern in Dallas and a current fellow at the Massachusetts General Hospital, and colleagues, presented at the 2022 Western Vascular Society annual meeting in Victoria, British Columbia, Canada (Sept. 17–20).

Those with CKD ranked 3b, 4, and 5—found to be high-risk—had worse one-year mortality rates compared to the remainder of the cohort, Khoury et al report, with CKD 1–3b patients showing a one-year mortality benefit following EVAR regardless of AAA size. “CKD 4 patients had no demonstrable benefit following EVAR at any AAA size. CKD 5 patients had worse actual one-year mortality rates with EVAR than predicted one-year mortality without EVAR for AAAs <5.5cm, although there was a mortality benefit with EVAR for AAAs >7.0cm in the CKD 5 group,” they elaborate. 

The patient pool was derived from the Vascular Quality Initiative (VQI), with nearly 35,000 patients meeting the study criteria. Some 8,183 (23.4%) were classed as CKD 1 patients, 16,888 (48.4%) CKD 2, 6,038 (17.3%) 3a, 2,708 (7.8%) 3b, 624 (1.8%) 4, and 485 (1.4%) CKD 5.

The research team noted notable differences in the baseline and operative characteristics: CKD 5 patients were less likely to be fully functional and were more likely to have a prior aortic aneurysm repair than the remainder of the cohort, while patients with CKD 1 and 2 had the lowest Gagne Indices, the measure used “to understand which subset of patients with CKD are most likely to experience a survival benefit following elective EVAR for AAAs,” while patients with CKD 3b and 4 had the highest.

Patients with CKD 3b, 4, and 5 had the longest operative times, they find. Khoury and colleagues comment that their study is noteworthy owing to the fact that it suggested CKD 5 patients being intervened on for AAAs less than 5.5cm “may be harmed if offered EVAR.” 

They explain: “The indication for repair for AAAs <5.5cm is unclear in this study. Nonetheless, we did find that CKD 5, in addition to CKD 1, had the highest proportion of patients with concomitant iliac artery aneurysms. Therefore, there is a possibility that the indication for repair was the iliac artery aneurysm rather than the AAA. This would lead to an underestimation of the predicted one-year mortality rate in these patients since the rupture risk of the iliac artery aneurysm was not accounted for with our methodology. The VQI defines an iliac artery aneurysm as anything greater than 2cm, which is below the recommended threshold for repair of 3.5cm, so we are unable to ascertain in the current study whether the iliac artery aneurysm was the indication for repair among patients with AAAs <5.5cm.” 

In an interview with Vascular Specialist, Khoury explained that combining the Gagne index and the predictive aneurysm-related mortality based off aneurysm size yields the prediction without repair. “We compared the prediction of one-year mortality without EVAR vs. what their actual one-year mortality is with EVAR, and then figure out which patients may benefit for repair,” he said. “This is obviously not a randomized-controlled trial, but what we found suggests that with advanced CKD patients, the underlying comorbidities are so high, the size threshold should be a little bit higher in these patients.” 

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