Predictors of diffuse renal microembolization following endovascular repair of abdominal aortic aneurysms

We evaluated the incidence, risk factors, and clinical consequences of renal microembolic events following endovascular aneurysm repair using suprarenal or infrarenal fixation. Pre- and postoperative (1 month) computed tomographic angiograms were reviewed for new renal perfusion defects. Suprarenal aortic and infrarenal neck thrombus load was classified by circumference involved and thrombus thickness. Serum creatinine was measured preoperatively, on the first postoperative day, and 1 month postoperatively. Among 136 patients, 8 (5.9%) had bilateral microembolic cortical defects. Patients with moderate or severe suprarenal thrombus were more likely to have renal microemboli than those with no or mild suprarenal thrombus (17% vs 0%; p < .001). Similarly, patients with moderate or severe infrarenal neck thrombus were more likely to have renal microemboli than those with no or mild infrarenal thrombus (9.6% vs 1.5%; p = .08). Severe infrarenal thrombus was independently predictive of microembolization (odds ratio 15.0; 95% confidence interval 1.6-142; p = .018). There was no statistically significant difference in the incidence of renal microembolization when comparing suprarenal and infrarenal fixation (8.2% vs 4.0%; p = .47). Changes in creatinine from baseline were not different in those with or without renal microemboli. Renal microembolization is an uncommon but distinct radiographic finding that is more associated with significant neck thrombus than fixation level.