Introduction:
The relationship of renal haemodynamics with cardiac and aortic hameodynamics is still unclear.
Hypothesis:
We evaluated the relationship of increased renal resistive index (RRI) with Augmentation index (AIx) and cardiac haemodynamics by means of mitral annular early diastolic velocity (E/Ea) in untreated patients with essential hypertension.
Methods:
76 newly diagnosed untreated non diabetic patients with stage I-II essential hypertension [35 males, aged 50 years, office blood pressure (BP) = 143/ 91 mm Hg], underwent ABPM, complete echocardiographic study for determination of E/Ea and blood sampling for assessment of metabolic profile. Moreover, data on renal resistive index (RRI), obtained by Doppler ultrasound sampling of the intrarenal arteries, as well as augmentation index (AIx), were retrospectively analyzed.
Results:
Based on the mean value of RRI (0.60), hypertensives were classified into those with high and low RRI. Hypertensives with high RRI values compared to those with low values were older (55.6±9.8 vs 44.4±11.6 years, p < 0.001), had lower 24-hour diastolic BP (77.5±7.7 vs 84.3±6.7 mmHg, p < 0.001), lower 24-hour HR (71.2±10.3 vs 76.2±9.2 bpm, p < 0.05), higher levels of AIx (27.2±8.2 vs 17.8±14.8 %, p < 0.01), and higher values of E/Ea (lateral) (7.7±1.8 vs 6.2±2.3, p < 0.05). In the total population, RRI was negatively related to 24-hour diastolic BP (r = -0.523, p < 0.001) and 24-hour HR (r = -0.281, p < 0.05), while it was positively associated with CRP (r = 0.335, p < 0.05), TChol (r = 0.296, p < 0.01), age (r = 0.443, r < 0.001), AIx (r = 0.413, p = 0.001) and E/Ea(lateral) (r = 0.465, p < 0.05). Multiple regression analysis revealed that 24-hour diastolic BP and E/Ea (lateral) were independent associated with RRI (R2 = 0.434, p < 0.05).
Conclusions:
Increased vascular resistance of intrarenal arteries is associated with impaired aortic and cardiac haemodynamics, as reflected by increased AIx and E/Ea (lateral) values. RRI may be considered a useful surrogate of haemodynamics in essential hypertension.
RENAL RESISTIVE INDEX IS RELATED TO CARDIAC AND AORTIC HAEMODYNAMICS IN THE EARLY STAGES OF ESSENTIAL HYPERTENSION