Predictive role of renal resistive index for clinical outcome after revascularization in hypertensive patients with atherosclerotic renal artery stenosis: a monocentric observational study.

BACKGROUND: The present study evaluated the predictive value of renal resistive index (RI) for renal function and blood pressure (BP) outcome in hypertensive patients with unilateral atherosclerotic renal artery stenosis submitted to successful revascularization. METHODS: In 158 hypertensive patients with atherosclerotic renal artery stenosis RI was acquired. Twelve months after revascularization, they were classified on the basis of renal function and BP outcome as benefit (BP < 140/90 mmHg or diastolic BP reduction > 15 mmHg with the same of reduced drugs; decrease in glomerular filtration rate > 20%), or failure. RESULTS: Regarding renal function outcome, RI in the stenotic and in the contralateral kidney were significantly higher in patients with failure (n = 20) than in those with benefit (0.72 ± 0.11 vs 0.61 ± 0.11 and 0.76 ± 0.08 vs 0.66 ± 0.09, p < 0.05). Among different cutpoints generated, RI in the contralateral kidney >0.73 provided the largest area under the curve (0.77), and the highest sensitivity (80%) and specificity (72%). In the multivariate logistic regression analysis, RI in the contralateral kidney >0.73 was an independent predictor of a failure in renal function outcome.Regarding BP outcome, patients with no benefit from revascularization (n = 60) had similar RI in the stenotic and contralateral kidney (p = ns), but presented higher pulse pressure, albuminuria and hypertension duration in comparison to patients with improved BP control. CONCLUSIONS: RI in the contralateral kidney is an independent predictor of renal function outcome after successful revascularization in hypertensive patients with unilateral atherosclerotic renal artery stenosis, whereas it is not able to predict blood pressure outcome.

Relationship between wave reflection and renal damage in hypertensive patients: a retrospective analysis.

OBJECTIVE: Arterial stiffening has harmful effects; peripheral pulse wave reflections deleteriously increase central pressure, but on the contrary they could also possibly be protective, as the pulse is transmitted to the microcirculation to a lesser extent. The aim of this study was, therefore, to explore the relationship between wave reflection and small vessel damage in the kidney. METHODS: In 216 hypertensive patients, data on renal resistive index, obtained by Doppler ultrasound sampling of the interlobar arteries, as well as augmentation index (AIx) and carotid-to-femoral pulse wave velocity (PWV), were retrospectively analyzed. Reflection magnitude was computed through a triangular flow estimate. RESULTS: AIx and reflection magnitude were positively correlated with resistive index; age, BMI, central pulse pressure, and cholesterol, but not AIx or reflection magnitude, were predictors of resistive index in multivariate analyses. Crossing tertiles of PWV and AIx, resistive index did not differ between patients with high AIx and low PWV (n=25; 0.632 (0.064)) and those with low AIx and high PWV (n=17; 0.645 (0.053)), despite a difference in reflection magnitude (74.9 (6.7) vs. 51.2 (7.3)%; P<0.001). CONCLUSION: Pressure wave reflection is positively correlated with resistive index in a hypertensive population. No negative relationship was found even adjusting for confounders or when it was examined separately from the influence of arterial stiffness. These findings do not support the hypothesis of peripheral wave reflections having a significant protective role for the microcirculation of a low resistance vascular bed such as the kidney.