Microalbuminuria, blood pressure load, and systemic vascular permeability in primary hypertension.
BACKGROUND
Microalbuminuria, a powerful predictor of cardiovascular events, is thought to reflect widespread subclinical vascular abnormalities. To explore the pathogenesis of increased urinary albumin excretion in primary hypertension we evaluated systemic capillary permeability and ambulatory blood pressure (BP) measurement in two groups of matched untreated patients with (n = 11) and without (n = 29) microalbuminuria.


METHODS
Albuminuria was measured as the mean of albumin-to-creatinine ratio (ACR) in three nonconsecutive first morning urine samples. Systemic capillary permeability was evaluated by transcapillary escape rate of albumin (TERalb) (ie, the 1-h decline rate of intravenous (125)I-albumin). Twenty-four-hour ambulatory BP, renal hemodynamics, and hormones of the renin-angiotensin-aldosterone system (RAAS) were also assessed.


RESULTS
Patients with microalbuminuria showed greater body mass index (BMI) (P < .04), higher 24-h systolic and diastolic BP levels (P = .02), and higher capillary permeability to albumin (P < .02) as compared to normoalbuminurics. Renal hemodynamics and RAAS hormones were similar in the two groups. Univariate analysis showed that urinary ACR was related to ambulatory pressure components (P < .02), TERalb (r = 0.31, P < .05), smoking habits (r = 0.36, P = .02), and left ventricular mass index (LVMI) (r = 0.57, P < .001) among the whole study group. Logistic regression analysis showed that each 1% increment in TERalb or 10 mm Hg increase in systolic BP entailed an almost three times higher risk of having microalbuminuria.


CONCLUSIONS
Microalbuminuria is associated with greater systemic BP load and increased vascular permeability in patients with primary hypertension.
Viazzi
Francesca
F
Department of Internal Medicine and Cardionephrology, Azienda Universitaria Ospedale San Martino, University of Genoa, Genoa, Italy.
Leoncini
Giovanna
G
Ratto
Elena
E
Vaccaro
Valentina
V
Tomolillo
Cinzia
C
Falqui
Valeria
V
Parodi
Angelica
A
Conti
Novella
N
Deferrari
Giacomo
G
Pontremoli
Roberto
R
D000328:Adult; D000368:Aged; D000419:Albuminuria / Q000503:physiopathology*; D001794:Blood Pressure / Q000502:physiology; D018660:Blood Pressure Monitoring, Ambulatory; D002199:Capillary Permeability; D005260:Female; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012079:Renal Circulation / Q000502:physiology; D012084:Renin-Angiotensin System / Q000502:physiology