Abstract

Objective- Albuminuria can be caused by endothelial dysfunction as a result of ischemic nephropathy rather than classical diabetic nephropathy. We studied whether renal vascular resistance (RI) of the main renal arteries could be associated with albuminuria, and further assessed the relationship between RI and aorta stiffness measured by brachial-ankle pulse wave velocity (baPWV).

Research design and methods- We consecutively studied 150 patients with type 2 diabetes mellitus (DM) and the absence of clinically overt RAS. Renal function expressed as eGFR (estimated glomerular filtration rate) was calculated using the modified formula of Modification of Diet in Renal Disease (MDRD). The RI ((peak systolic velocity – end-diatolic velocity)/peak systolic velocity) was measured with duplex Doppler ultrasonography.

Results- When the presence of albuminuria (uAlb) was defined as urinary albumin-to-creatinine ratio (μg/mg·creatinine) greater than 30, mean RI ((left RI+right RI)/2) was significantly higher in uAlb, compared with that in patients without uAlb. RI had significant associations with age (r=0.398, P<0.0001), diastolic BP (DBP) (r=-0.398, P<0.0001), eGFR (r=-0.373, P<0.0001), and baPWV (r=0.223, P<0.05), respectively. Multivariate logistic regression analysis showed that increased RI when defined as RI>0.72 (median) was significantly associated with age (P<0.01, 95%CI 1.02-1.19), DBP (P<0.01, 95%CI 0.86-0.97), and uAlb (P<0.01, 95%CI 1.53-15.46), respectively. Moreover, RI was an independent risk factor for uAlb after adjustment of both diastolic blood pressure and eGFR.

Conclusions- Renal vascular resistance was associated with albuminuria and aorta stiffness. Increased RI may imply the presence of any type of underlying renal damage including ischemic nephropathy.