Objectives To compare the prevalence of hemodynamically significant stenosis between renal arteries with and without variations in resistant hypertensive patients, and to determine whether aberrant renal arteries are associated with higher renin activity and impaired renal function in essential hypertensive patients.
Methods 292 consecutive resistant hypertensives (212 male and 80 female, mean age 47.4 ± 15.7 yrs) underwent renal artery CTA or MRA to screen for secondary hypertension, two blinded readers evaluated CTA and MRA images for the presence of aberrant renal arteries and hemodynamically significant renal artery stenosis ( > 50%), and discrepancies were resolved by consensus reading. For all the patients, blood samples were collected in the morning after been out of bed for at least 2 h to assess plasma renin activity and aldosterone level, GFR was measured by 99mTc-DTPA to assess bilateral renal function.
Results A single renal artery was present in both kidneys in 76.4% of the patients. Renal artery variations were found in 23.6% of the cases, including multiple renal arteries in 0.7%, accessory renal arteries in 21.9%, and early division in 2.0%. There was no difference in the prevalence of significant renal artery stenosis between patients with and without aberrant renal arteries (23.3% vs, 22.4%, P = 0.87). For patients with aberrant renal arteries, there was no difference in the prevalence of renal artery stenosis between renal arteries with and without variations (13.0% vs, 11.6%, P = 0.71). Among the patients diagnosed with essential hypertension, 53/226(23.5%) were with renal artery variations, 173/226 (76.5%) were not. Aldosterone level (log-transformed) was similar between these two groups (219.4 ± 116.5 pg/ml vs. 211.1 ± 153.6 pg/ml, P = 0.58). However, plasma renin activity was slightly higher in the former group (3.52 ± 2.42 ng/ml·h vs. 3.19 ± 2.74 ng/ml·h, P = 0.02). Self-paired t-test revealed that there was no difference in GFR between kidneys supplied by renal arteries with and without variations (46.9 ± 10.8 vs. 45.0 ± 11.8, P = 0.29).
Conclusions Renal artery variations are not associated with higher susceptibility to developing renal artery stenosing lesions and impaired renal function. Essential hypertensives with aberrant renal arteries are prone to have high plasma renin activity.