Cerebral hypoperfusion has occasionally been reported during essential hypertension. We explored regional cerebral blood flow in a large series of neurologically asymptomatic hypertensive patients to ...determine relations among cerebral blood flow, concomitant main vascular risk factors, and the most common signs of end-organ damage.
Regional cerebral blood flow was measured by the 133Xe inhalation method in 101 hypertensive patients without clinically apparent central nervous system involvement, including 39 mild to moderate untreated and 62 mild to severe treated patients.
Compared with age- and sex-matched normal control subjects, cerebral blood flow was significantly reduced in untreated hypertensive patients (P < .01) and to a lesser extent in treated patients (P = .047). Both regional and global cerebral blood flow reductions were observed in approximately one third of patients in both groups. Analysis of variance failed to show significant correlations between cerebral blood flow and total cholesterol concentration, mean arterial blood pressure, duration of disease, or the presence of retinopathy or left ventricular hypertrophy. In the treated group, the quality of control of hypertension significantly influenced both global cerebral blood flow (P = .007) and cerebrovascular resistance (P < .0001).
Focal or diffuse cerebral hypoperfusion is present even in neurologically asymptomatic hypertensive patients, especially when untreated; good control of blood pressure may preserve cerebral perfusion and reduce cerebrovascular resistance. Regional cerebral blood flow examination represents a relatively simple and low-cost technique to explore the perfusional condition of the brain, one of the main target organs of hypertensive disease.
The presence of mild renal dysfunction is associated with high cardiovascular morbidity and mortality rates in patients with primary hypertension. The pathophysiological mechanisms underlying this ...association are currently unknown. We investigated the relation between mild renal dysfunction and subclinical cardiovascular organ damage in 358 never previously treated patients with primary hypertension. Mild renal dysfunction was defined as a creatinine clearance <60 mL/min and/or the presence of microalbuminuria. Left ventricular mass index and carotid intima-media thickness were assessed by ultrasound scan. The prevalence of mild renal dysfunction, left ventricular hypertrophy, and carotid plaque was 18%, 48%, and 28%, respectively. Mild renal dysfunction was related to the presence of several risk factors, such as older age, higher blood pressure levels and lipid status, and smoking habits. Patients with the highest left ventricular mass and carotid intima-media thickness (upper quartiles) showed a higher prevalence of mild renal dysfunction (P<0.0001). After adjusting for duration of hypertension, mean blood pressure, smoking habits, and age, we found that the risk of left ventricular hypertrophy and/or carotid atherosclerosis increased by 43% with each SD reduction in creatinine clearance, and by 89% with each SD increase in albuminuria. Mild renal dysfunction is associated with preclinical end-organ damage in patients with primary hypertension. These data may help explain the high cardiovascular mortality rates reported in patients with low glomerular filtration rate or with increased albuminuria. The evaluation of creatinine clearance and urinary albumin excretion could be useful for identifying subjects at higher cardiovascular risk.
Subclinical renal damage and hyperuricemia are not uncommon in patients with primary hypertension. Whether mild hyperuricemia reflects a subclinical impairment of renal function or contributes to its ...development is currently debated. We investigated the relationship between serum uric-acid levels and the occurrence of early signs of kidney damage.
Four hundred eighteen patients with primary hypertension were studied. Albuminuria was measured as the albumin-to-creatinine ratio, and creatinine clearance was estimated by the formula of Cockcroft and Gault. Interlobar resistive index and renal abnormalities, ie, the renal volume-to-resistive index ratio, were evaluated by renal Doppler and ultrasound.
Uric acid was directly related to resistive index (
P = .007) in women and to albuminuria (
P = .04) in men, and was inversely related to the renal volume-to-resistive index ratio in both men (
P = .005) and women (
P = .02). Patients with uric-acid levels above the median showed a higher prevalence of microalbuminuria (14%
v 7%,
P = .012) and of renal abnormalities (41%
v 33%,
P = .007). Moreover, when creatinine clearance was taken as a covariate, patients with increased uric-acid levels showed higher albuminuria and resistive indices, and a lower renal volume-to-resistive index ratio. Even after adjustment for several risk factors, each standard deviation increase in serum uric acid entailed a 69% higher risk of microalbuminuria, and a 39% greater risk of ultrasound detectable renal abnormalities.
Mild hyperuricemia is associated with early signs of renal damage, ie, microalbuminuria and ultrasound-detectable abnormalities, regardless of the glomerular filtration rate in primary hypertension.
In the past years, several risk charts have been created to increase the accuracy of cardiovascular risk stratification. The most widely used and validated algorithms do not included target organ ...damage as risk prediction. The aim of the present study was to evaluate whether preclinical renal damage is associated with cardiovascular diseases independently of individual risk profile assessed by risk charts.
The study population was that of Italy-Developing Education and awareness on MicroAlbuminuria in patients with hypertensive Disease, a large observational study conducted on hypertensive patients in Italy. The Framingham Risk Score (FRS), Systematic COronary Risk Estimation (SCORE) and Progetto Cuore Risk Score (Progetto Cuore RS) were computed in each eligible patient. Chronic kidney disease was defined by the presence of albuminuria or by a reduction of glomerular filtration rate.
Study participants were categorized to have low, medium and high risk according to the tertiles of the three charts. Prevalence of total cardiovascular diseases progressively and significantly increased according to the degrees of risk assessed by the three charts, the highest prevalence being in participants with a high-risk profile (both high and medium vs. low risk <0.01 for FRS, SCORE and Progetto Cuore RS). The presence of chronic kidney disease was associated with total cardiovascular diseases, independently of FRS (odds ratio 1.64, 95% confidence interval 1.33-2.02, P < 0.001), SCORE (odds ratio 1.55, 95% confidence interval 1.21-1.98, P < 0.001) and Progetto Cuore RS (odds ratio 1.59, 95% confidence interval 1.22-2.07, P < 0.001). Moreover, inclusion of renal damage in the logistic model significantly increased the accuracy of the FRS (P < 0.05), SCORE (P < 0.01) and Progetto Cuore RS (P < 0.01) to identify patients with overt cardiovascular diseases.
Identification of patients with preclinical renal damage should be encouraged in the hypertension cardiovascular risk stratification setting in order to achieve a more accurate individual risk computation. The presence of renal damage could improve cardiovascular risk prediction over the widely used risk stratification charts.
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 m2 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 (χ2 5.2, P < 0.05), microalbuminuria (χ2 10.2, P < 0.01), and CKD (χ2 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). Conclusion Early renal abnormalities are associated with reduced CFR in PH.
Mild renal dysfunction (MRD) is an often overlooked but relatively common condition in patients with primary hypertension (PH), and is associated with high cardiovascular morbidity and mortality. ...Whether MRD is also associated with abnormalities in renal vascular resistance is currently unknown.
Two hundred ninety-one untreated patients with PH were studied. The MRD was defined as a creatinine clearance ≥60 mL/min but <90 mL/min (Cockcroft-Gault formula) or the presence of microalbuminuria. Albuminuria was measured as the albumin-to-creatinine ratio in first morning urine samples. Renal resistive index (RI) was evaluated by ultrasound Doppler of the interlobar arteries.
The prevalence of MRD in our cohort was 63%. Patients with MRD were older, had higher mean blood pressure (BP), pulse pressure, and total cholesterol, longer history of hypertension, and were more likely to be men. Renal RI was positively related to female gender, age, systolic BP, pulse pressure, total cholesterol, albuminuria, and to carotid wall thickness and cross-sectional area, whereas it was inversely related to diastolic BP and creatinine clearance. Patients with the highest renal resistance (upper quartile, ≥0.63) showed a greater prevalence of renal dysfunction (P = .0005). After adjusting for age, pulse pressure, and LDL-cholesterol, we found that the risk of MRD increased twofold (P = .04) when renal RI was ≥0.63.
A reduction in creatinine clearance and the presence of microalbuminuria are associated with increased renal vascular impedence, as well as with signs of extrarenal arterial stiffness.
Preventing subclinical organ damage is currently a major issue in the management of patients with essential hypertension. Antihypertensive drugs which act through different pathophysiological ...mechanisms might confer specific target organ protection beyond what is already provided by their blood pressure lowering effect.
Thirty-one patients with essential hypertension were randomized to receive long-term treatment with either a calcium channel blocker (nifedipine GITS, 90 mg/day) or an ACE-inhibitor (lisinopril, 20 mg/day). Blood pressure, left ventricular mass, carotid wall thickness and timed urinary albumin excretion were measured at baseline and over the course of 24 months of treatment.
Both regimens significantly lowered mean blood pressure over the 24 months (from 124+/-2 to 103+/-2 mmHg in the lisinopril group and from 122+/-2 to 104+/-1 in the nifedipine group). Overall, end-organ damage improved with persistent blood pressure control. However, the two treatments had different specific effects. Lisinopril induced a more pronounced reduction of the left ventricular mass index (from 56+/-3 to 52+/-2 g/m2.7, P< 0.05) and urinary albumin excretion (from 34+/-15 to 9+/-2 microg/min, P< 0.01), while nifedipine achieved a greater reduction of carotid intima plus media thickness (from 0.8+/-0.06 to 0.6+/-0.06 mm, P< 0.01).
Blood pressure control does help reduce the severity of organ damage in patients with essential hypertension. Different antihypertensive treatments may confer additional specific cardiorenal and vascular protection regardless of blood pressure control. These data could be useful when devising individualized therapeutic strategies in high-risk hypertensive patients.
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