■ FEATURED ABSTRACT Is fibromuscular dysplasia (FMD) underdiagnosed? A comparison of the prevalence of fmd seen in patients enrolled into the CORAL trial versus a single institution population of renal donor candidates

Purpose We postulate that FMD is underdiagnosed. Therefore, we evaluated the prevalence of renal artery FMD in patients enrolled into the CORAL renal artery stent trial, in which the presence of renal artery FMD was an exclusion criterion for trial enrollment. We also evaluated the prevalence of FMD in a relatively healthy population of patients undergoing screening CT angiography (CTA) for comparison. Materials and Methods Following IRB approval, we did a retrospective review of renal donor preoperative CTAs performed and interpreted by fellowship trained cardiovascular imaging physicians at our institution between 1/2003 and 11/2011. These results were then compared to the findings from the angiographic core lab (ACL) for the CORAL renal artery stent trial in which patients with FMD were theoretically excluded from trial enrollment. Data was assessed for the presence of renal artery FMD and the patient’s age and gender. Results The CORAL ACL database contained 1014 patients (mean age = 69.4 years) and there were 504 males (49.7%) and 510 females (50.3%). Fifty-eight CORAL trial patients (5.7%) were found to have incidental renal artery FMD (95% CI [4.4, 7.35]). The mean age of these 58 patients was 71.8 years, and 44 were female (75.9%). The preoperative kidney donor population included 220 consecutive patients (mean age = 40.5 years). There were 78 males (35.5%) and 142 females (64.5%). Five patients (2.3%) had evidence of FMD. The mean age of these 5 patients was 48.6 years and all 5 (100%) were female. Conclusion The prevalence of renal artery FMD of 2.3% is consistent with prior reports (1,2). However, the prevalence of FMD of 5.7% in the more elderly CORAL population (which was biased against the selection of patients with FMD) suggests that FMD is underdiagnosed in patients with atherosclerotic renal artery stenosis. The female predilection for renal FMD remains in patients of 70 years of age. References 1. Lorenz EC, et al. Prevalence of renal artery and kidney abnormalities by computed tomography among healthy adults. Cl J Am Soc Neph. 2010 Mar;5(3):431-8. 2. Cragg AH, et al. Incidental fibromuscular dysplasia in potential renal donors: long-term clinical follow-up. Radio. 172(1989):145-7.