Coronary flow reserve is impaired in hypertensive patients with subclinical renal damage.
BACKGROUND
Renal dysfunction is relatively common in patients with primary hypertension (PH). A reduction in coronary vasodilator capacity has recently been reported in patients with renal damage undergoing coronary angiography. We investigated the relationship between coronary flow reserve (CFR) and early renal abnormalities in patients with PH and normal serum creatinine.


METHODS
Seventy-six untreated patients were studied. Albuminuria was measured as the albumin-to-creatinine ratio and glomerular filtration rate (eGFR) was estimated by the Cockroft-Gault formula. Chronic kidney disease (CKD) was defined as an eGFR <60 ml/min/1.73 m(2) and/or in the presence of microalbuminuria. Coronary blood flow velocities (cm/s) were measured by Doppler ultrasound at rest and after adenosine administration. CFR was defined as the ratio of hyperemic-to-resting diastolic peak velocities.


RESULTS
Prevalence of reduced eGFR, microalbuminuria, CKD, and left ventricular (LV) hypertrophy was 8, 10, 16, and 31%, respectively. Overall, 10% of patients showed impaired CFR (i.e., <2.0). Patients with CKD were more likely to be older (P < 0.05) and of female gender (P < 0.01) and showed higher LV mass index (LVMI) (P < 0.05), lower CFR (P < 0.05; analysis of covariance, P < 0.05), and CFR/LVMI (P < 0.05) than patients with normal renal function. Conversely, patients with impaired CFR showed a significantly higher prevalence of reduced eGFR (chi(2) 5.2, P < 0.05), microalbuminuria (chi(2) 10.2, P < 0.01), and CKD (chi(2) 9.2.1, P < 0.01). Even after adjustment for gender, the presence of CKD entailed a sevenfold higher risk of having impaired CFR (confidence interval 1.17-40.9, P < 0.05).


CONCLUSIONS
Early renal abnormalities are associated with reduced CFR in PH.
Bezante
Gian P
GP
Division of Cardiology, Department of Internal Medicine, University of Genoa, Azienda Ospedaliera Universitaria San Martino, Genoa, Italy.
Viazzi
Francesca
F
Leoncini
Giovanna
G
Ratto
Elena
E
Conti
Novella
N
Balbi
Manrico
M
Agosti
Sergio
S
Deferrari
Luca
L
Deferrari
Giacomo
G
Pontremoli
Roberto
R
D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D003326:Coronary Circulation / Q000502:physiology*; D018618:Echocardiography, Doppler, Color; D005260:Female; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D051436:Renal Insufficiency, Chronic / Q000150:complications / Q000503:physiopathology*