A young woman presented for altruistic kidney donor evaluation. She had no significant past medical history other than two normal prior pregnancies. Physical examination was unremarkable. A CT angiogram revealed bilateral irregularities of the renal arteries and a 0.9 mm aneurysmal dilatation of right renal artery seen in the figure. Home blood pressures were normal and labs were otherwise unremarkable.
In an asymptomatic, normotensive young adult female with an incidental finding of fibromuscular dysplasia (FMD) with bilateral renal artery involvement is it safe to proceed with altruistic kidney donation?
FMD is seen in approx 4% of patients worked up for kidney donation. The natural history is that in the majority of patients the lesions are non-progressive. In one study, primary and assisted primary patency rates were 66% and 87% at 5 years and the restenosis rate was 28% at 5 years. Hypertension improved or resolved within 3 months in 72% of patients and this was maintained in 73% at 5 years. After surgical revascularization long-term blood pressure control was maintained in 93% of patients and improvement or stabilization of renal function was noted in 92%.
Anecdotal case reports and case series suggest that despite patients being normotensive at the time of kidney donation patients with FMD can develop future radiological worsening of renal artery lesions, hypertension or ischemic renal disease. Kidney donors with FMD thus are potentially more likely to develop hypertension compared to kidney donors without FMD.
In the case discussed above, given the young age of the patient, bilateral nature of lesions and the presence of a renal aneurysm we recommended against altruistic kidney donation. We were also concerned that the recipient might develop hypertension post transplant given the irregularities that would be present in the transplanted renal artery.
The evidence would suggest that aneurysms that are >1.0 cm, non-calcified or found in pre-menopausal women are at high risk of rupture. Our patient had 2 out of these 3 criteria and therefore underwent coiling of the aneurysm with excellent results.
Author: Gautam Phadke, MD