Prognostic Significance of the Renal Resistive Index After Renal Artery Revascularization in the Context of Flash Pulmonary Edema

Abstract

Purpose: To evaluate the prognostic value of the renal resistive index (Ri) after renal artery revascularization in the context of flash pulmonary edema.

Methods: Between 2000 and 2008, 43 patients (mean age 72.1±10.9 years; 23 women) underwent renal artery angioplasty/stenting in the context of flash pulmonary edema. Intrarenal Ri was assessed using duplex ultrasound. The majority (97.7%) of patients had hypertension, and nearly half (46.5%) had diabetes mellitus. For this retrospective analysis, the patients were divided into 2 groups according to the median Ri (<0.8 and ≥0.8) of the population. A Cox proportional hazards model was used to identify predictors of all-cause mortality (primary endpoint) and rehospitalization for heart failure; the results are presented as the hazard ratio (HR) and 95% confidence interval (CI). The mean follow-up was 49.8±30.6 months.

Results: There was no difference between the groups regarding clinical characteristics. A high Ri was associated with the risk of all-cause death (HR 2.54, 95% CI 1.15 to 5.60, p=0.021). This relationship was still statistically significant after adjustment for age, gender, diabetes, glomerular filtration rate, and treatment with a renin-angiotensin system inhibitor (HR 1.74, 95%CI 1.08 to 2.81, p=0.032). A high Ri was also associated with cardiovascular death in unadjusted and adjusted analyses. In contrast, a high Ri was not associated with the risk of rehospitalization for heart failure.

Conclusion: After renal artery revascularization for flash pulmonary edema, a high intrarenal Ri is independently associated with all-cause mortality. Determination of the intrarenal Ri after this procedure may be useful for identifying at-risk patients.

Keywords: angioplasty; flash pulmonary edema; prognosis; renal artery stenosis; renal resistive index.