Association of intrarenal blood flow with renal function and target organ damage in hypertensive patients with fibromuscular dysplasia: the ARCADIA-POL study.

INTRODUCTION Data on the assessment of intrarenal blood flow parameters in patients with renal fibromuscular dysplasia (FMD) are scarce. OBJECTIVES The aim of the study was to evaluate intrarenal blood flow parameters in patients with FMD and significant or nonsignificant renal artery stenosis (RAS). PATIENTS AND METHODS We evaluated intrarenal blood flow parameters by Doppler ultrasonography in 153 patients with renal FMD enrolled in the ARCADIA­POL study: 32 and 121 patients with and without significant RAS, respectively, compared with 60 matched patients with essential hypertension and 60 healthy controls. RESULTS Patients with FMD and significant RAS had a lower renal resistive index (RRI) compared with patients with FMD without significant RAS, patients with essential hypertension, and normotensive controls (mean [SD], 0.51 [0.08] vs 0.60 [0.07], 0.62 [0.06], and 0.61 [0.06], respectively; P <0.001). In patients with nonsignificant RAS, RRI correlated significantly with carotid intima-media thickness, 24­hour diastolic blood pressure, 24­hour pulse pressure, left ventricular diastolic function, known duration time of hypertension, and age. In patients with significant RAS, there was a significant correlation between RRI and known duration time of hypertension, left ventricular diastolic function, and age. In a separate, "per­kidney" analysis, renal arteries with FMD and significant RAS were characterized by lower RRI values, higher maximal blood flow velocity, higher renal aortic ratio, and longer acceleration time compared with renal arteries with FMD and nonsignificant RAS as well as renal arteries without FMD. CONCLUSIONS In contrast to atherosclerotic RAS, intrarenal blood flow in patients with FMD and RAS is preserved, confirming that renal vasculature is relatively intact in these patients.