Relationship of renal dysfunction to proximal arterial disease severity in atherosclerotic renovascular disease

Abstract

Renal impairment is common in patients with atherosclerotic renovascular disease (ARVD), but its pathogenesis is uncertain. This study investigated whether any relationship existed between renal function and the severity of proximal renal arterial lesions in patients with ARVD. A cohort of 71 patients had creatinine clearance measured at the time of digital subtraction angiography; eight patients were diabetics and were excluded from further analysis. The severity of proximal renovascular lesions was estimated by standard methodology, and patients were sub-grouped according to residual patency of the proximal renal arteries (e.g. normal=2.0; unilateral occlusion )RAO(=1.0). Renal bipolar lengths at ultrasound were also assessed. Sixty-three non-diabetic patients (mean+/-SD age 67.7+/-5.8 years; 34 males) were suitable for study. No differences in renal function (mean+/-SD creatinine clearance (ml/min)) were seen between patients with unilateral (32. 1+/-18.9, n=36) or bilateral (31.7+/-20.9, n=27) disease, or between sub-groups with RAS <60% (28.3+/-13.9, n=15), unilateral RAS >60% (38.9+/-24.6, n=12), bilateral RAS >60% (36.3+/-20.4, n=6) or unilateral RAO (30.3+/-17.7, n=28), and mean average renal size similarly did not differ between the sub-groups. No correlation existed between residual patency and creatinine clearance (r=0.015); mean+/-SD renal function was almost identical in the four patency sub-groups, and average renal size mirrored this pattern. Mean 24-h urinary protein excretion was similar for the four groups, but patients with minimal ARVD had significantly less comorbid vascular disease. These findings suggest that the severity of proximal renal artery lesions is often unrelated to the severity of renal dysfunction in patients with ARVD. Associated renal parenchymal damage is the more probable arbiter of renal dysfunction, and this should be considered when revascularization procedures are contemplated.