Microalbuminuria and subclinical cerebrovascular damage in essential hypertension.
BACKGROUND
Microalbuminuria is a marker of hypertensive and atherosclerotic organ damage in essential hypertension and has powerful prognostic value for cerebral and cardiovascular morbidity and mortality. An association between carotid artery intima-media thickness (IMT) and increased urinary albumin excretion (UAE) has been reported in patients with essential hypertension, suggesting a link between microalbuminuria and atherosclerotic stroke mechanism(s).


METHODS
We investigated the relationships between UAE, carotid artery changes, and asymptomatic cerebrovascular damage in two groups of untreated essential hypertensive patients, with (n=11) and without (n=11) microalbuminuria. The study groups, selected among participants in a large epidemiological trial, were carefully matched for several potential confounding variables such as sex, age, duration of hypertension, and body mass index. None had neurological abnormalities. Albuminuria was measured as albumin excretion rate (UAE) on three overnight collections; microalbuminuria was defined as between 20-200 microg/min. Carotid IMT was assessed by high resolution US scan, cerebral lacunar lesions by magnetic resonance imaging (MRI), and left ventricular mass index (LVMI) by M-B mode echocardiography. Office and 24-h ambulatory blood pressures (ABP, Takeda 2420) were also recorded.


RESULTS
There were no differences between the two groups in office and ABP, lipid profile and smoking habits. Microalbuminuric patients had a higher prevalence of cerebral ischemic lacunae (82 vs 27%; P=0.03, OR=12, confidence interval - CI 1.6-91.1), and higher carotid IMT (0.94+/-0.05 vs 0.75+/-0.06 mm; P=0.03) than normoalbuminuric patients. No differences were found in LVMI and in the prevalence of Left Ventricular hypertrophy. Patients with ischemic lacunae showed a higher prevalence of microalbuminuria (75 vs 22%; P=0.03, OR=12, CI 1.0-13.5) and higher UAE (58.7+/-21.8 vs 9.4+/-3.7 mg/mmol, P=0.01) than to patients with normal MRI.


CONCLUSIONS
Microalbuminuria is an early marker of preclinical brain damage in essential hypertension and may therefore be useful for identifying patients at higher risk of cerebral and cardiovascular events, for whom preventive therapeutic measures are advisable.
Ravera
Maura
M
Department of Internal Medicine, Section of Nephrology, University of Genoa, Italy.
Ratto
Elena
E
Vettoretti
Simone
S
Viazzi
Francesca
F
Leoncini
Giovanna
G
Parodi
Denise
D
Tomolillo
Cinzia
C
Del Sette
Massimo
M
Maviglio
Nicola
N
Deferrari
Giacomo
G
Pontremoli
Roberto
R
D000368:Aged; D000419:Albuminuria / Q000150:complications / Q000175:diagnosis*; D000704:Analysis of Variance; D001795:Blood Pressure Determination; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging / Q000473:pathology; D015331:Cohort Studies; D004452:Echocardiography; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000175:diagnosis*; D002537:Intracranial Arteriosclerosis / Q000150:complications / Q000175:diagnosis*; D016015:Logistic Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011336:Probability; D011379:Prognosis; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D020521:Stroke / Q000150:complications / Q000175:diagnosis*; D014655:Vascular Resistance