Renal Artery Stenosis by Three-dimensional Magnetic Resonance Angiography in Type 2 Diabetics with Uncontrolled Hypertension and Chronic Renal Insufficiency: Prevalence and Effect on Renal Function

Background: The variable course of renal disease in type 2 diabetes mellitus in part may reflect associated atherosclerotic nephropathy.

Methods: To determine the influence of subcritical (<65%) renal artery stenosis (RAS) on the progression of chronic kidney disease, 45 patients with type 2 diabetes with uncontrolled hypertension and serum creatinine levels of 1.8 mg/dL or greater (>/=159.1 micromol/L) were screened by three-dimensional magnetic resonance angiography (MRA). Mean monthly decrease in reciprocal serum creatinine x 100 and time to initiation of dialysis therapy, adjusting for baseline serum creatinine level, were compared in those with and without RAS. Follow-up was censored at the time of death or angioplasty.

Results: At baseline, RAS-negative (RAS(-); n = 27) and RAS-positive (RAS(+); n = 18) groups were similar in duration of diabetes and hypertension, hyperlipidemia, blood pressure, diabetic management, and renal function. RAS(+) subjects were older (P = 0.04) and more likely to have claudication (P = 0.006), smoke (P = 0.02), and have heart disease (P = 0.06). During a median follow-up of 9.4 months, 3 patients underwent stent placement, 2 patients died, and 12 patients progressed to dialysis therapy. The RAS(+) group had a more rapid monthly decline in reciprocal serum creatinine x 100 (mean, 1.63 +/- 0.9 versus 0.69 +/- 1.0 [SD]; P = 0.04). The relative risk for progression to end-stage renal disease was 2.4 in the RAS(+) versus RAS(-) group. Multivariate analysis showed that this effect was not independent of several established atherosclerotic risk factors.

Conclusion: MRA-detected RAS is common (40%) in patients with type 2 diabetes with uncontrolled hypertension and renal insufficiency. Subcritical (<65%) RAS is a significant risk factor for progressive renal failure.