Objective: We examined the value of renal resistive index (RRI) for prevalence of cardiovascular target organ damage in therapy-resistant hypertension in comparison to low-grade albuminuria.
Methods: Eighty-four patients with therapy-resistant hypertension (age 59.7 +/- 8.1 years) were screened for cardiovascular target organ damage with coronary computed tomography, cardiac magnetic resonance imaging (MRI), Doppler sonography for the assessment of carotid intima media thickness and, RRI, pulse wave velocity and for low-grade albuminuria of at least 10 mg/day in men and 15 mg/day in women, respectively.
Results: In patients with RRI greater than 0.7 pulse wave velocity (11.6 +/- 3.7 vs. 9.8 +/- 2.2 m/s; P = 0.02) intima media thickness (0.85 +/- 0.09 vs. 0.76 +/- 0.1 mm; P = 0.007) and Agatston score of coronary calcification (640 +/- 915 vs. 129 +/- 256; P = 0.05) were increased, whereas left ventricular mass (127 +/- 24.5 vs. 125 +/- 15.0 g; P = 0.70) was similar between the two groups. When patients were categorized according to low-grade albuminuria left ventricular mass was significantly higher in those with low-grade albuminuria (123 +/- 25.8 vs. 135 +/- 15.7 g; P = 0.01), whereas vascular parameters (intima media thickness, Agatston score, pulse wave velocity) did not differ between the two groups.
Conclusion: In patients with therapy-resistant hypertension RRI reflects functional and structural vascular parameters, whereas low-grade albuminuria is related to cardiac structural changes. Thus, measurement of RRI in addition to low-grade albuminuria complements screening for target organ damage in therapy-resistant hypertension.