Renal autoregulation in medical therapy of renovascular hypertension

Abstract

IntroductionRenovascular hypertension (RVH) is caused by renal ischaemia associated with haemodynamically significant renal artery stenosis (RAS). The choice of optimal treatment of atherosclerotic RAS is still controversial. Increase in the renal resistive index (RI) value after captopril administration is considered to indicate preserved renal autoregulation. The objective of the study was to assess the effect of medical therapy of RVH on renal autoregulation efficiency in patients with atherosclerotic RAS.Material and methods19 persons (38 kidneys) in 2 groups: 1) study: with RVH and stenosis of 1 renal artery – 8 patients; 2) control: – 11 healthy volunteers. Doppler captopril test with RI measurements and estimation of creatinine clearance (CCr) were performed in both groups at baseline, and after a period of controlled medical therapy (CMT) only in the study group. ABPM was evaluated in controls at baseline, and in the study group at the end of CMT.ResultsIn the study group the mean period of CMT was 8.3 ±2.7 months, the number of antihypertensive drugs was 4.1 ±1.0, and mean 24-hour blood pressure was 138/74 mmHg. Mean CCr was stable during the study. Significant increase of RI after captopril was found only in controls. At baseline, in the group of kidneys with a non-stenotic renal artery, significant lowering of RI was observed, and ΔRI differed significantly from controls. After CMT, ΔRI increased in non-stenotic kidneys in comparison to the baseline, and did not differ from controls.ConclusionsAdequate medical therapy of RVH preserved renal function and improved renal autoregulation efficiency in non-stenotic kidneys.

Impact of Cardiovascular Organ Damage on Cortical Renal Perfusion in Patients with Chronic Renal Failure

“…The right kidney was chosen because of better technical access for ultrasound investigation. RRI in segmental arteries was achieved as described before [15]. Mean of 2-3 measurements of RRI performed in the upper, middle, and lower regions of the renal sinus was calculated and considered for statistics.…”

“…To this day, in some publications, quantity of renal perfusion has been evaluated based on renal resistive index (RRI) obtained in the Doppler sonography [9, 10]. However, most studies suggest that RRI is not related to perfusion, or even vascular resistance, but it is rather a marker of hypertension control and vascular organ damage [11–15]. RRI value is not specific for either function or renal perfusion [7].…”

Renalase Gene Polymorphism in Patients with Hypertension and Concomitant Coronary Heart Disease

“…rs2576178 may influence the initiation of transcription and rs2296545 might change the gene functions via influencing the structure or functions of proteins. However, the ways and mechanisms by which renalase influences the blood pressure and myocardial ischemia to play a role in diseases are still poorly understood [25,26,27]. …”

Renal Perfusion Index Reflects Cardiac Systolic Function in Chronic Cardio-Renal Syndrome

“…Renal resistive index in segmental arteries was estimated as described before [ 8 ]. Mean value of RI was calculated from 2 or 3 measurements in the upper, middle and lower regions of the renal sinus.…”