Hemodynamic index of atheromatous renal artery stenosis for angioplasty

Background and objectives: Trans-stenotic pressure gradient across the constriction (PG), a hemodynamic variable of atheromatous renal artery stenosis (ARAS), is a widely used indicator for angioplasty, but its association with the outcome of angioplasty has not been fully investigated. Design, setting, participants & measurements: In 34 hypertensive cases with unilateral ARAS, we evaluated hemodymanic variables of ARAS with reference to the systemic BP reduction after angioplasty as the outcome. Results: In each phase, PG divided by its corresponding prestenotic arterial BP (PG/preBP) had better association with the outcome than PG. The mean phase PG/preBP had the largest area under the curve in the receiver operating characteristic analysis (0.794) with the sensitivity/specificity of 0.957/0.545 for its cut-off >0.15. Although the plasma renin activity, which reflects the perfusion to renal parenchyma, was higher in the angioplasty-efficacious cases than in the angioplasty- inefficacious cases before angioplasty (7.8 ± 6.6 versus 3.4 ± 3.8 ng/ml/h, P = 0.049), it was not generally reduced by angioplasty independent of the outcome. Conclusions: As the index to select ARAS for angioplasty, PG/preBP was better than PG and the mean phase PG/preBP could be the best. However, other factors such as the microvascular kidney disease, which affect the perfusion to renal parenchyma, would influence the outcome.