Prognostic significance of endothelial dysfunction in hypertensive patients

BACKGROUND

Forearm endothelial dysfunction, characterized by an impaired vasodilating response to acetylcholine (ACh), may be associated with several cardiovascular risk factors, including essential hypertension. Although the prognostic value of coronary endothelial dysfunction has been demonstrated, that of forearm endothelial dysfunction is still unknown. Methods and Results-- Endothelium-dependent and -independent vasodilation was investigated in 225 never-treated hypertensive patients (age, 35 to 54 years) by intra-arterial infusion of increasing doses of ACh and sodium nitroprusside. Patients were divided into tertiles on the basis of their increase in ACh-stimulated forearm blood flow (FBF) from basal: group 1, from 30% to 184%; group 2, from 185% to 333%; and group 3, from 339% to 760% increase from basal. During a mean follow-up of 31.5 of months (range, 4 to 84 months), there were 29 major adverse events at the cardiac (n=19), cerebrovascular (n=9), or peripheral vascular (n=1) level. Events included myocardial infarction, angina, coronary revascularization procedures, stroke, transient cerebral ischemic attack, and aortoiliac occlusive disease. Event rate per 100 patient-years was 8.17, 4.34, and 2.02 in the first, second, and third tertiles of peak percent increase in FBF during ACh infusion. The excess risk associated with an FBF increase in the first tertile was significant (relative risk, 2.084; 95% CI, 1.25 to 3.48; P=0.0049) after controlling for individual risk markers, including 24-hour ambulatory blood pressure.

CONCLUSIONS

Our data suggest that forearm endothelial dysfunction is a marker of future cardiovascular events in patients with essential hypertension.

Independent predictors of isolated clinic ('white-coat') hypertension

BACKGROUND

Hypertension guidelines recommend 24 h ambulatory blood pressure (ABP) monitoring in hypertensive subjects with suspected isolated clinic hypertension (ICH). However, the pre-test probability of ICH based on the distribution of its independent predictors has not yet been estimated in hypertensive subjects with mildly elevated blood pressure.

OBJECTIVE

To ascertain the independent predictors of ICH in mildly hypertensive subjects.

METHODS

In the setting of the HARVEST-PIUMA collaboration, we studied 1564 subjects with hypertension stage I. At entry, all subjects were untreated and all underwent ABP monitoring and echocardiography. Diabetes, hypertension grade > I, renal failure or previous cardiovascular morbid events were exclusion criteria. Clinic BP was 143/92 mmHg (SD 9/5) and 24 h ABP was 128/81 mmHg (SD 10/8).

RESULTS

Prevalence of ICH (daytime ABP < 130 mmHg systolic and 80 mmHg diastolic) was 10.4%. In a multivariate logistic regression analysis, sex (P = 0.002), smoking (P = 0.038) and clinic diastolic BP (P = 0.0002) were the sole independent predictors of ICH according to the following equation: Y = 2.6438 + 0.5128 x sex (0 = men; 1 = women) + 0.4543 x current smoking (0 = yes; 1 = no) - 0.0531 x clinic diastolic BP (mmHg) and P (probability of ICH) = exp(Y)/[1 + (exp(Y)]. Left ventricular (LV) mass at echocardiography was a further independent predictor (P = 0.002) of ICH according to the following equation: Y= 3.4343 + 0.4603 x sex + 0.5989 x current smoking - 0.0482 x clinic diastolic BP - 0.0312 x LV mass [g/height (m)2.7]. LV mass was greater (P < 0.01) in the group with ambulatory hypertension [42.3 g/height (m)2.7] than in that with ICH [39.2 g/height (m)2.7] and not dissimilar between the ICH group and a control group of 370 healthy normotensive subjects [38.1 g/height (m)2.7].

CONCLUSIONS

In untreated subjects with stage I hypertension, ICH is most frequent among women, nonsmokers and subjects with low clinic BP and smaller LV mass. These findings allow identification of subjects with indication to ABP monitoring because of suspected ICH.

Different prognostic impact of 24-hour mean blood pressure and pulse pressure on stroke and coronary artery disease in essential hypertension

BACKGROUND

We tested the hypothesis that the steady and pulsatile components of blood pressure (BP) exert a different influence on coronary artery disease and stroke in subjects with hypertension.

METHODS AND RESULTS

We analyzed data on 2311 subjects with essential hypertension. All subjects (mean age 51 years, 47% women) underwent off-therapy 24-hour ambulatory BP monitoring. Over a follow-up period of up to 14 years (mean 4.7 years), there were 132 major cardiac events (1.20 per 100 person-years) and 105 cerebrovascular events (0.90 per 100 person-years). After adjustment for age, sex, diabetes, serum cholesterol, and cigarette smoking (all P<0.01), for each 10 mm Hg increase in 24-hour pulse pressure (PP), there was an independent 35% increase in the risk of cardiac events (95% CI 17% to 55%). Twenty-four-hour mean BP was not a significant predictor of cardiac events after controlling for PP. After adjustment for age, sex, and diabetes (all P<0.05), for every 10 mm Hg increase in 24-hour mean BP, the risk of cerebrovascular events increased by 42% (95% CI 19% to 69%), and 24-hour PP did not yield significance after controlling for 24-hour mean BP. Twenty-four-hour PP was also an independent predictor of fatal cardiac events, and 24-hour mean BP was an independent predictor of fatal cerebrovascular events.

CONCLUSIONS

In subjects with predominantly systolic and diastolic hypertension, ambulatory mean BP and PP exert a different predictive effect on the cardiac and cerebrovascular complications. Although PP is the dominant predictor of cardiac events, mean BP is the major independent predictor of cerebrovascular events.

Original articles prognostic value of combined echocardiography and ambulatory blood pressure monitoring in hypertensive patients at low or medium cardiovascular risk

BACKGROUND

The clinical value of echocardiography and ambulatory blood pressure monitoring (ABPM) in hypertensive patients at low immediate risk of cardiovascular disease is still unknown.

METHODS

Echocardiography and ABPM were performed in 715 untreated subjects with essential hypertension World Health Organization/International Society of Hypertension stage I or II and low or medium cardiovascular risk defined by the absence of diabetes, previous cardiovascular events, left ventricular (LV) hypertrophy at electrocardiography, proteinuria, stages III-IV retinopathy and creatinine levels > 106.08 mmoll (1.2 mg/dl) and the presence of one or two traditional risk factors.

RESULTS

The LV mass was increased in 26.5% of these subjects. Subjects with a limited blood pressure reduction from day to night (non-dippers) were 11.3%. Over 1-13 years of follow-up, 31 subjects developed a first major cardiovascular event. The event rate (per 100 person-years) was 0.60 in the subgroup with a normal LV mass vs 1.63 in that with an increased LV mass (p < 0.017), and 0.74 in dippers vs 3.75 in non-dippers (p < 0.001). On multivariate analysis, the relative risk of cardiovascular events was 1.70 (95% confidence interval-CI 1.23-2.36) for each 11 g/m(2.7) increment in LV mass (p < 0.01), and 2.77 (95% CI 1.12-6.83) in non-dippers vs dippers (p < 0.05). Overall, on the basis of results of combined echocardiography and ABPM, 33% of subjects were at increased risk of future cardiovascular events.

CONCLUSIONS

At standard first-line work-up performed on hypertensive subjects at low or medium cardiovascular risk, combined echocardiography and ABPM identify an increase in the risk of subsequent cardiovascular disease in one third of subjects.

[Blood pressure components and target organ damage]

In a given hypertensive patient, clinically overt cardiovascular disease is often preceded by a number of signs of target organ damage at the cardiac, arterial and renal levels. These changes have been collectively defined "pre-clinical cardiovascular disease", and carry a substantially increased risk for future cardiovascular complications. The present article examines the relationship between blood pressure components and target organ damage in essential hypertension. Arterial pressure can be split into a steady component (represented by the mean arterial pressure), which is a measure of the average level of pressure in a given artery, and a pulsatile component (represented by the pulse pressure), which estimates the cyclic oscillations around the mean. All blood pressure components show a positive, linear correlation with left ventricular mass, both in the general population and in patients with essential hypertension. However, the association is significantly stronger for the steady blood pressure components (systolic and mean arterial pressure) than for the pulse pressure. Available data regarding arterial changes suggest that the association is partly different. The majority of available studies show that large-artery intima-media thickening and discrete atherosclerotic plaques are better predicted by pulse pressure than by other blood pressure components, particularly in the elderly. After the age of 60, there is clear-cut evidence for a J-shaped relationship between diastolic blood pressure and arterial thickening or plaques, while for younger age groups the relationship appears to be linear. These data might offer an explanation for the observed superior prognostic value of pulse pressure in the elderly. The relationship between the different blood pressure components and renal damage is more controversial. In summary, pulsatile, cyclic stress (as represented by pulse pressure) appears to be more important in determining arterial changes in hypertensive patients, while steady blood pressure components play a dominant role in the development of hypertensive left ventricular hypertrophy.

High-normal serum creatinine concentration is a predictor of cardiovascular risk in essential hypertension

BACKGROUND

Determination of serum creatinine concentration is recommended in all patients with hypertension as a marker of target organ damage. However, the possibility that creatinine values within the reference range might contribute to stratification of cardiovascular risk in essential hypertension has never been tested.

PATIENTS AND METHODS

In the setting of the Progetto Ipertensione Umbria Monitoraggio Ambulatoriale Study, for up to 11 years (mean, 4 years) we followed up 1829 white patients with hypertension (mean +/- SD age, 51 +/- 12 years; 53% men; office blood pressure, 157/98 mm Hg) free of cardiovascular events and with normal pretreatment creatinine levels (men, <136 micromol/L [<1.5 mg/dL]; women, <120 micromol/L [<1.4 mg/dL]) who also underwent 24-hour blood pressure monitoring and electrocardiography before therapy.

RESULTS

During follow-up, there were 175 fatal or nonfatal major cardiovascular morbid events (2.4 per 100 patient-years). Event rate increased progressively from the first to the fourth sex-specific quartiles of creatinine distribution (1.5, 2.3, 2.3, and 3.5 per 100 patient-years; P =.003 by log-rank test). After adjustment (in a multivariate Cox model) for age, sex, diabetes, cholesterol, smoking, left ventricular hypertrophy, and 24-hour pulse and mean blood pressures (P<.05 for all), creatinine concentration was an independent adverse predictor of cardiovascular morbid events (P =.01). The observed excess risk was 1.30 (95% confidence interval, 1.07-1.59) for a 20-micromol/L (0.23-mg/dL) increase in creatinine concentration.

CONCLUSIONS

A serum creatinine value within the reference range is a predictor of cardiovascular morbidity in white patients with essential hypertension. Its prognostic value persists after adjustment for several powerful confounders, including average 24-hour blood pressure and left ventricular hypertrophy.

Postprandial lipemia and associated metabolic disturbances in healthy and hyperlipemic postmenopausal women

The increased risk for coronary artery disease observed in postmenopausal women is partly explained by a more atherogenic fasting lipoprotein profile. Moreover, natural menopause has been associated with an altered postprandial lipid profile. To better characterize the interaction between fasting and postprandial lipid profile after menopause, we examined postprandial changes in several lipid parameters in three age-matched groups of postmenopausal women (16 affected by mixed hyperlipemia, 17 by common hypercholesterolemia, and 17 normolipemic), who underwent a standardized oral fat-loading test. The magnitude of postprandial lipemia, expressed as 8-hour triglyceride incremental area under the curve, was greater in women with mixed hyperlipemia (1,326 +/- 372 mg x dL(-1) x h(-1)) than in normal (484 +/- 384 mg x dL(-1) x h(-1)) and hypercholesterolemic (473 +/- 223 mg x dL(-1) x h(-1); both P <.0001) women, and the differences held after adjustment for body mass index and fasting insulin. Women with mixed hyperlipemia showed a significant postprandial decrease in high-density lipoprotein 2 (HDL(2)) cholesterol, lipoprotein (a), and low-density lipoprotein (LDL) particle size. Both hypercholesterolemic and normolipemic women showed a significant postprandial decrease in HDL cholesterol and lipoprotein (a) levels but not in LDL size. In a multiple linear regression analysis, fasting triglyceride levels, insulin level, and waist-hip ratio were all independent predictors of the magnitude of postprandial lipemia. In conclusion, postmenopausal women with mixed hyperlipemia show a greater postprandial triglyceride increase and a more pronounced reduction in HDL cholesterol level and LDL size than hypercholesterolemic and normolipemic subjects. The presence of the features of insulin resistance syndrome could contribute to the deterioration of postprandial lipemic response in these subjects.

Prognostic value of midwall shortening fraction and its relation with left ventricular mass in systemic hypertension

We followed 1,778 subjects (up to 12 years) with essential hypertension who underwent echocardiography at the time of their initial diagnostic workup. There were 166 major cardiovascular events during follow-up and the prognostic value of the midwall shortening fraction did not remain significant after controlling for left ventricular mass.

Relation between serum uric acid and risk of cardiovascular disease in essential hypertension. The PIUMA study

The question of serum uric acid as an independent risk factor in subjects with essential hypertension remains controversial. For up to 12 years (mean, 4.0) we followed 1720 subjects with essential hypertension. At entry, all subjects were untreated and all were carefully screened for absence of cardiovascular disease, renal disease, cancer, and other important disease. Outcome measures included total cardiovascular events, fatal cardiovascular events, and all-cause mortality. During 6841 person-years of follow-up there were 184 cardiovascular events (42 fatal) and 80 deaths from all causes. In the 4 quartiles of serum uric acid (division points: 0.268, 0.309, and 0.369 mmol/L [4.5, 5.2, and 6.2 mg/dL] in men; 0.190, 0.232, and 0.274 mmol/L [3.2, 3.9, and 4.6 mg/dL] in women), the rate (per 100 person-years) of cardiovascular events was 2.51, 1.48, 2.66, and 4.27, that of fatal cardiovascular events was 0.41, 0.33, 0.38, and 1.23, and that of all-cause deaths was 1.01, 0.55, 0.93, and 2.01, respectively. The relation between uric acid and event rate was J-shaped in both genders. After adjustment for age, gender, diabetes, total cholesterol/HDL cholesterol ratio, serum creatinine, left ventricular hypertrophy, ambulatory blood pressure, and use of diuretics during follow-up, uric acid levels in the highest quartile were associated with increased risk for cardiovascular events (relative risk, 1.73; 95% CI, 1.01 to 3.00), fatal cardiovascular events (relative risk, 1.96; 95% CI, 1.02 to 3.79), and all-cause mortality (relative risk, 1.63; 95% CI, 1.02 to 2.57) in relation to the second quartile. In untreated subjects with essential hypertension, raised uric acid is a powerful risk marker for subsequent cardiovascular disease and all-cause mortality.

Impaired flow-mediated vasoactivity during post-prandial phase in young healthy men

Impaired flow-mediated vasodilation in large arteries is an expression of endothelial dysfunction and an established marker of early atherosclerosis. Post-prandial lipemia can induce an impairment of the endothelial function. The aim of our study was to evaluate the effects of post-prandial phase on flow-mediated vasodilation in a group of ten young (23 +/- 2 years) healthy men without cardiovascular risk factors, who underwent an oral fat-loading test. Flow-mediated vasodilation of the brachial artery and serum lipid profile were assessed under fasting conditions and 2, 4, 6 and 8 h after a high-fat meal. Triglycerides increased from 0.6 +/- 0.2 fasting to 1.1 +/- 0.5 and 1.3 +/-0.6 mmol/l at the 2nd and 4th hour (both P < 0.01), and decreased thereafter. Flow-mediated vasodilation fell significantly from 14.5 +/- 6.6% fasting to 3.5 +/- 1.5% and 4.0 +/- 2.2% at the 2nd and 4th hour (both P < 0.01), and returned to the basal values at the 6th and 8th hour. A strong inverse correlation was observed between the area under the incremental curve of post-prandial triglycerides (i.e. after subtraction of baseline triglycerides) and the area under the decremental curve of post-prandial flow-mediated vasodilation (r = -0.70, P = 0.025). No association was found between post-prandial vasodilation changes and fasting triglycerides, other lipid parameters or insulin. We conclude that a transient post-prandial impairment in brachial artery flow-mediated vasodilation is evident in young healthy men after a high-fat meal, and is closely associated with triglyceride levels. These data provide support for a role of post-prandial phase in vascular regulation in young healthy subjects.

Short-term atorvastatin treatment improves endothelial function in hypercholesterolemic women

Endothelial dysfunction represents the earliest stage of atherosclerosis and is usually present in hypercholesterolemia. Treatment with statins has been shown to normalize endothelial function in middle-aged men with hypercholesterolemia. We evaluated the effect over time of atorvastatin on the endothelial reactivity in postmenopausal hypercholesterolemic women (mean age, 58 +/- 6 years), receiving atorvastatin, 10 mg daily (n = 20) or American Heart Association step 1 diet (n = 10) for 8 weeks. Lipid profile and brachial artery flow-mediated vasodilation (FMV) were determined at baseline and after 1, 2, 4, and 8 weeks. FMV increased progressively in subjects treated with atorvastatin, and the difference was significant (p < 0.05 vs. baseline) after the second week (baseline 3.8 +/- 3%; first week, 4.8 +/- 3%; second week, 9.2 +/- 3%; fourth week, 11.0 +/- 3%; eighth week, 11.7 +/- 3%). No significant changes were observed in subjects receiving diet (baseline, 3.1 +/- 4%; first week, 2.4 +/- 2%; second week, 2.9 +/- 2%; fourth week, 3.1 +/- 2%; eighth week, 3.3 +/- 2%; p = NS). In the atorvastatin group, low-density lipoprotein (LDL) cholesterol showed a significant decrease since the first week (baseline, 228 +/- 37 mg/dl; first week, 171 +/- 32; second week, 147 +/- 27; fourth week, 139 +/- 29; eighth week, 135 +/- 27; all p < 0.05). In the control group, LDL cholesterol showed a smaller but significant (p < 0.05) reduction after the second week (baseline, 226 +/- 17 mg/dl; first week, 225 +/- 16; second week, 220 +/- 17; fourth week, 203 +/- 27; eighth week, 198 +/- 27). In conclusion, hypercholesterolemic women treated with atorvastatin show a significant improvement in endothelial reactivity after as early as 2 weeks of therapy. The extent to which these beneficial effects are attributable to cholesterol reduction or to a direct effect of the drug remains to be established.

Flow-mediated vasoactivity and circulating adhesion molecules in hypertriglyceridemia: association with small, dense LDL cholesterol particles

BACKGROUND

Endothelial dysfunction is considered one of the earliest events in the process of atherosclerosis, and an impaired vasodilatory response has been reported in patients with dyslipidemias. However, the independent association between hypertriglyceridemia and endothelial dysfunction is controversial, and the relation between endothelium-dependent vasodilation and circulating cell adhesion molecules as markers of endothelial dysfunction has not been fully determined.

METHODS

Brachial artery flow mediated vasodilation (FMV) and the soluble forms of vascular cell adhesion molecule-1 (sVCAM-1) and intercellular adhesion molecule-1 (sICAM-1) were determined after overnight fasting in 16 men with hypertriglyceridemia (age 33 +/- 6 years) and in 16 age-matched healthy men with normal triglycerides and cholesterol. Subjects who smoked and those with known cardiovascular disease, diabetes, hypertension, recent or active infections, or any other disease that could affect leukocyte activation were excluded from the study.

RESULTS

Compared with normal subjects, subjects with hypertriglyceridemia showed a higher level of sVCAM-1 and sICAM-1 (both P <.001), a reduced FMV (P <.01), and a smaller LDL particle size (P <.05). FMV had a significant inverse correlation with sVCAM-1 (r = -0.61, P <.001) and sICAM-1 (r = -0.38, P <.03). LDL particle size had a strong, direct association with FMV (r = 0.75, P <.001) and an inverse association with adhesion molecules. By multiple regression analysis, triglycerides (P <.001) and small LDL particle size (P <.002) predicted a reduced FMV.

CONCLUSIONS

Serum level of cell adhesion molecules is increased and FMV is impaired in young healthy men with hypertriglyceridemia compared with age-matched men with normal lipid levels. Small, dense LDL particles may play a role in determining endothelial dysfunction in these subjects.

Subclinical left ventricular dysfunction in systemic hypertension and the role of 24-hour blood pressure

The relation between blood pressure (BP) and left ventricular (LV) systolic function in systemic hypertension is controversial. We assessed the relation of LV midwall fractional shortening (FS) to 24-hour BP in 1,702 never-treated hypertensive subjects (age 48 +/- 12 years), who underwent 24-hour BP monitoring and echocardiography. Stress-corrected endocardial and midwall FS (the latter calculated taking into account the epicardial migration of midwall during systole) were predicted in hypertensives on the basis of the values observed in 130 healthy normotensives (age 43 +/- 13 years, office BP 126/78 mm Hg). Subjects below the fifth percentile of observed-to-predicted FS had depressed LV function. The use of midwall FS resulted in an increase from 3.5% to 17.5% in the proportion of patients with depressed chamber function. Compared with the group with normal function, subjects with low midwall LV function had similar office systolic BP (155 +/- 21 vs 154 +/- 17 mm Hg), but increased 24-hour systolic BP (140 +/- 17 vs 133 +/- 12 mm Hg, p <0.001). Midwall FS had a closer negative relation to 24-hour systolic BP than to office systolic BP (r = -0.27 vs -0.08, p <0.001), whereas this difference was not apparent for diastolic BP (r = -0.23 vs -0.20). Compared with endocardial FS, midwall FS had a stronger inverse association to LV mass (r = -0.45 vs -0.16, p <0.001). Thus, an increased 24-hour BP load may chronically lead to depressed myocardial function in systemic hypertension in the absence of clinically overt heart disease.

Should all patients with hypertension have echocardiography?

The feasibility of echocardiographic determination of left ventricular (LV) mass, as well as the advantages that might be gained in some clinical circumstances and possible indications are examined in the present review, in relation to the recent WHO/ISH. The information obtained with echocardiograms in arterial hypertension is an important contribution to risk stratification on an epidemiological scale. In clinical practice, under the ascertained condition of a good reliability, an echocardiogram should be recommended as part of the initial work up when patients meet criteria for not starting therapy (low or mild risk WHO-ISH) or in all circumstances in which decision-making might be affected by the echocardiographic result. At present, there is not sufficient evidence to extend the indication of echocardiography also to patients for whom antihypertensive management is already necessitated by identification of high or very high risk status.

Long-term effects of losartan and enalapril, alone or with a diuretic, on ambulatory blood pressure and cardiac performance in hypertension: a case-control study

BACKGROUND

The long-term effects of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers on ambulatory blood pressure and cardiac performance have never been examined comparatively.

OBJECTIVE

We compared losartan and enalapril in their long-term effects on office and ambulatory blood pressure, cardiac structure and function, and routine biochemical tests.

DESIGN

In the setting of the Progetto Ipertensione Umbria Monitoraggio Ambulatoriale (PIUMA) study, 22 hypertensive subjects were studied with ambulatory blood pressure monitoring and echocardiography before and after an average of 3.3 years of treatment with losartan 50mg daily. These subjects were matched in a 1:3 ratio with a group of 66 subjects treated with enalapril 20mg daily. Case-control sampling was based on age (+/-5years), sex, pre-treatment office blood pressure (+/-5mmHg) and ambulatory blood pressure (+/-5mmHg), and duration of treatment (+/-6months). An additional group of subjects who interrupted their treatment with enalapril (n=18) or losartan (n =2) because of unwanted effects before execution of the follow-up study was not included in the analysis.

RESULTS

Hydrochlorothiazide was added during follow-up in order to optimize blood pressure control (office blood pressure <140mmHg systolic and 90mmHg diastolic) in 10 subjects (45%) in the losartan group and 34 subjects (52%) in the enalapril group. Office and ambulatory blood pressures were lowered to a similar extent by losartan and enalapril. Left ventricular mass decreased from 98 to 87g/m(2) with losartan (P <0.01) and from 98 to 89 g/m(2) with enalapril (P <0.01). The change in left ventricular mass over time was more closely associated with the change in ambulatory blood pressure than with office blood pressure in both groups. Left ventricular internal diameter did not change with either drug. The endocardial shortening fraction, mid-wall shortening fraction and Doppler indexes of active diastolic relaxation did not change with either drug. None of the biochemical parameters showed a significant change. Serum uric acid showed a slight and non-significant reduction only in the losartan group.

CONCLUSION

In this case-control study in uncomplicated subjects with essential hypertension, losartan and enalapril, alone or combined with a diuretic, effectively and equally lowered office and ambulatory blood pressure and induced a significant reduction in left ventricular mass during long-term treatment. Left ventricular systolic and diastolic function remained unchanged with either regimen.