Abstract 11832: Interrelationships of Cardiorenal Hemodynamics in Untreated Hypertensives. An Invasive Approach
Objective: Measurement of renal resistive index (RRI) has been used to assess the severity of renal damage in hypertension. Coronary flow reserve (CFR) is often used to express coronary microvascular function and asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, is a marker of endothelial dysfunction.The aim of the present study was to evaluate the relationship of renal hemodynamics with coronary microcirculation, endothelial function and albuminuria in untreated essential hypertensive subjects.
Methods: For this purpose, we studied 24 hypertensive patients (aged 57.7 years, 10 males) with indications of myocardial ischemia and normal coronary and renal arteries in the coronary and renal angiography. Renal blood flow velocity was measured by a 0.014 in. Doppler flow wire (Flowire, Volcano) in the renal artery. RRI was calculated as: (peak systolic velocity - end-diastolic velocity) / peak systolic velocity. CFR was calculated by using also Flowire in the left anterior descending artery in response to bolus intracoronary administration of adenosine (60μ g) as the ratio of hyperemic to basal average peak velocity of the distal vessel. Serum creatinine levels (sCr), glomerular filtration rate (eGFR according to MDRD formula) and ADMA were assessed from a morning blood sample. Albumin excretion was determined as the ratio of albumin to creatinine (ACR) on two non-consecutive morning spot urine samples.
Results: In the entire study population RRI was negatively correlated with CFR (r=-0.530, p=0.008) while no correlation was observed with age, sex, anthropometric characteristics as well as blood pressure levels measured during catheterization of the renal artery. Moreover, RRI was positively correlated with ADMA (r=0.570, p=0.006), logACR (r=0.410, p=0.046) and negatively correlated with eGFR (r=-0.423, p=0.040).
Conclusions: Increased vascular resistance is associated with impaired coronary microcirculation, endothelial dysfunction and kidney damage (as reflected by increased albumin excretion and reduced eGFR). RRI may be considered a useful hypertensive target organ damage surrogate.
- © 2011 by American Heart Association, Inc.