White-coat hypertension and cardiovascular risk

OBJECTIVE

To compare cardiovascular risk in white-coat hypertensives, normotensives and established hypertensives.

METHODS

We studied 61 hypertensive individuals, 27 of whom were white-coat hypertensives, and 35 normotensives. All subjects underwent 24 h noninvasive blood pressure monitoring and Doppler echocardiographic examination of the heart; urine was tested for microalbuminuria and the fundi of the eyes examined for retinopathy.

RESULTS

The 24 h as well as the day- and night-time mean systolic blood pressure (SBP) was slightly but significantly higher in white-coat hypertensives than in normotensives; no significant difference was observed in diastolic blood pressure (DBP) between these groups. In white-coat hypertensives, 24 h SBP and DBP were lower than in established hypertensives (P < 0.001). The echocardiographic study showed higher values of posterior wall thickness, left ventricular mass index (LVMI), and ventricular septum thickness (P < 0.05) in white-coat hypertensives than in normotensives; fractional shortening and ejection fraction were similar. The E:A ratio, obtained from the Doppler study, was lower in white-coat hypertensives than in normotensives (1.14 +/- 0.3 versus 1.24 +/- 0.25; P < 0.05). LVMI values were smaller in white-coat hypertensives than in established hypertensives (P < 0.05), and both ejection fraction and fractional shortening were similar in the two groups. Among white-coat hypertensives, eight out of 27 showed hypertensive retinal damage; microalbuminuria values were similar to those obtained in normotensives.

CONCLUSIONS

The results of this cross-sectional and therefore limited study lead us to hypothesize that white-coat hypertensives are at higher risk than normotensives and lower risk than established hypertensives for developing cardiovascular damage.

Blood pressure pattern importance in the development of left ventricular hypertrophy in hypertension

Heterogeneous results regarding correlations between blood pressure, (measured by various methods and in different conditions), and left ventricular mass in arterial hypertension have been reported. Fifty-three essential hypertensives, I-II WHO stage, have been studied in order to verify the relationship between office and average 24-hour blood pressure, and its day- and night-time pattern with left ventricular hypertrophy. All patients had newly diagnosed essential hypertension, and no subject had received any antihypertensive therapy before entry. The subjects underwent 24-hour blood pressure monitoring, evaluating the average of 24 hours, day- and night-time blood pressures, and M-mode echocardiography. Neither subjects with nor without left ventricular hypertrophy showed correlations between office blood pressure and left ventricular mass. On the contrary, average 24-hour systolic and diastolic blood pressure resulted related to left ventricular mass (r = 0.36 and 0.40, p less than 0.01 respectively). Furthermore, in the subgroup with left ventricular hypertrophy, left ventricular mass was correlated directly with nocturnal systolic blood pressure (r = 0.46) and inversely with the rate of nocturnal decrease in systolic pressure (r = -0.60, p less than 0.01). These results appear to confirm the usefulness of 24-hour blood pressure monitoring in evaluating cardiac afterload in essential hypertension, and the important role that the 24-hour systolic pressure has in the development of left ventricular hypertrophy in these subjects.

Reversal of cardiac hypertrophy and left ventricular function with the calcium antagonist felodipine in hypertensive patients

A study was carried out to evaluate the influence of antihypertensive treatment with a calcium antagonist on left ventricular hypertrophy and to estimate left ventricular performance after reversal of myocardial hypertrophy. Ten essential hypertensives (age 45 +/- 2 years; WHO class II) underwent an M-mode echocardiogram guided by two-dimensional echocardiography, during a wash-out period and after 3, 6 and 12 months of treatment with felodipine ER 10 mg/daily. At month 12 the echocardiogram was also performed during a handgrip test. BP levels during the treatment period decreased significantly, and left ventricular mass index showed a significant reduction from 143 +/- 13 to 112 +/- 9 g/m2 (P less than 0.001). A significant increase occurred in fractional shortening (FS) which was associated with decreases in end-systolic stress (ESS), left ventricular internal diameter (LVIDs) and inotropic state indices. Moreover, after reversal of myocardial hypertrophy left ventricular performance remained unchanged. Linear regression analysis showed a significant correlation of FS with ESS, which remained significant until the end of the study period, both at rest and at peak handgrip test (r = -0.68; P less than 0.05 and r = -0.80, P less than 0.01 respectively). This study demonstrates a significant decrease in left ventricular mass during treatment with a dihydrophyridine calcium antagonist and a good maintenance of left ventricular performance following reversal of myocardial hypertrophy in hypertensives.

[Ketanserin and metoprolol in the treatment of essential hypertension]

In a controlled clinical study, 30 adult patients (16 females, 14 males, mean age 46.0 +/- 7.6, mean body weight 69.4 +/- 10.2 kg) with mild-moderate essential hypertension were treated with ketanserin (20 mg twice daily) or metoprolol (100 mg daily) for the first month and 40 mg twice daily or 100 mg twice daily during the second month. Results showed antihypertensive efficacy and systemic tolerability of ketanserin to be equal to that of metoprolol and better cardiac tolerance for ketanserin.

[Microalbuminuria, an early marker of renal changes in essential hypertension]

The purpose of this study was to verify if microalbuminuria (AER) could be an early feature of renal hemodynamic changes in essential hypertension. Fifty-three patients with newly diagnosed essential hypertension (EH) underwent 24-hour blood pressure monitoring (24h-BP). Furthermore, AER and glomerular filtration rate (GFR) were evaluated by obtaining 24-hour urine collection: day- and night-time urine was kept separate. Data from the 53 EH patients were analyzed both collectively and after subdivision into two subgroups based on AER values (less or more than 16 micrograms/min). In the 53 EH patients, 24h-AER correlated significantly to both 24h systolic and diastolic blood pressure (BP) (r = 0.58 and 0.67, respectively). The subgroup with AER greater than 16 micrograms/min showed higher values of 24h-BP and GFR than the other subgroup. Moreover, in the first subgroup, 24h-systolic BP (r = 0.61) and 24h-diastolic BP (r = 0.68) correlated with AER. Our data seem to indicate that among the hypertensive patients, there is a subgroup of subjects whose hypertensive disease is characterized by high blood pressure as well as elevated microalbuminuria and glomerular filtration rate values. Increased microalbuminuria in newly diagnosed hypertensive disease seems to be due to glomerular hypertension and early altered microvascular permselectivity, and would thus indicate an early clinical expression of altered renal hemodynamics.

Epinephrine and norepinephrine pattern in elderly patients with borderline and established hypertension

To evaluate the activity of sympathetic system and of plasm renin in elderly patients with borderline (BH) and established essential hypertension (EH), 31 BH mean age 38 years and 30 EH, mean age 39 years; 15 BH, mean age 66 years, and 15 EH, mean age 68 years, were studied at rest and after dynamic exercise. At the same time blood pressure and heart rate were automatically recorded, while blood samples were collected for PRA and plasma epinephrine (E) and norepinephrine (NE) assays. Plasma E levels showed no significant differences between the groups examined at rest. Nevertheless, young BH had higher plasma E levels than young EH after stress and elderly BH showed plasma E levels higher than age-matched EH in response to dynamic exercise. The PRA behaviour was similar among all the groups, but dynamic exercise induced a greater increase in BH than in EH. Moreover, the stress-induced increase in plasma NE levels was higher in EH than in BH. Our results demonstrate in old BH, as well as in young BH, a response of E to stress greater than in the age-matched EH. In our study BH, both young and old subjects, seem to be characterized by a sympathoadrenal overactivity pointed out by an excessive release of E from the adrenal gland after stress. This exaggerated sympathoadrenal reactivity may constitute an important mechanism in triggering hypertension independent of age.

Sympathetic activity in borderline and established hypertension in the elderly

Although increased sympathetic outflow has been implicated in the induction of early essential hypertension, the increase in norepinephrine with advancing age could reflect a compensatory mechanism for a declining peripheral response to adrenergic stimuli or an age-related decrease in norepinephrine clearance. To evaluate the activity of the sympathetic system and of plasma renin in elderly patients with borderline and established essential hypertension, 31 borderline hypertensives aged less than 60 years (mean age 38 years), 30 established essential hypertensives aged less than 60 years (mean age 39 years), 15 borderline hypertensives aged greater than 60 years (mean age 66 years) and 15 essential hypertensives aged greater than 60 years (mean age 68 years) were studied at rest and after dynamic exercise. Blood pressure and the heart rate were automatically recorded and blood samples were collected for plasma renin activity and plasma epinephrine and norepinephrine assays. Plasma epinephrine levels showed no significant differences between the groups examined at rest. Nevertheless, young borderline hypertensives had higher plasma epinephrine levels than young essential hypertensives after stress, and elderly borderline hypertensives showed higher plasma epinephrine levels than the age-matched essential hypertensives in response to dynamic exercise. The plasma renin activity profile was similar among all the groups, but dynamic exercise induced a greater increase in borderline than in essential hypertensives. Moreover, the stress-induced increase in plasma norepinephrine levels was higher in essential than in borderline hypertensives. Our results show a greater epinephrine response to stress in elderly and young borderline hypertensives than in age-matched essential hypertensives.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of epinephrine in the development of essential hypertension

Recently, it has been showed that Epinephrine (E) plays an important role in the pathogenesis of essential hypertension in rats. Furthermore, some literature data demonstrated the existence of high E plasma levels at rest and after stress in essential hypertension. To evaluate the sympatho-adrenal activity, both in basal condition and after stress, and its relationship with the renin-angiotensin-aldosterone (RAA) system, 31 borderline hypertensives (BH), 30 essential hypertensives (EH), and 15 healthy subjects were studied. After a wash-out period and electrolyte evaluation, all subjects were studied at rest, during dynamic exercise, and after 30 minutes of recovery; at the same time blood pressure and heart rate were automatically recorded and blood samples were collected for plasma renin activity (PRA), E, Norepinephrine (NE) and aldosterone plasma concentrations assay. BH showed a percentage increase of mean blood pressure greater than EH (p less than 0.01) during dynamic exercise. PRA showed no significant differences between the 3 groups examined at rest; on the contrary, PRA levels and the percentage increases were significantly higher in BH than in EH (p less than 0.05 respectively). E plasma levels and its percentage increases were significantly greater in BH than both in EH (p less than 0.05) and in controls after exercise. Furthermore, raised E plasma levels lasted significantly throughout the recovery period (p less than 0.05) only in BH. A significant correlation between both E plasma levels and percentage increases with NE percentage increases was observed after exercise in BH. Our results demonstrate a sympatho-adrenal overactivity in borderline hypertension, which is characterized by a prolonged E hyper-responsiveness, a renin hyper-secretion and a high hemodynamic response to stress. In borderline hypertension, E, excessively released from the adrenal gland, may act as a sympathetic cotransmitter inducing functional adrenoceptors hyperactivity.

Effects of dynamic exercise and metabolic control on left ventricular performance in insulin-dependent diabetes mellitus

In subclinical diabetic cardiomyopathy, previous reports did not positively correlate the altered cardiac performance with metabolic parameters. Fifteen insulin-dependent diabetic subjects, without any clinical or instrumental evidence of heart diseases, were studied. Signs of diabetic microangiopathy were absent. Systolic time intervals, metabolic and hormonal parameters (blood glucose, free fatty acids, blood lactate and plasma norepinephrine) were evaluated at rest and after dynamic exercise during poor (MAGE 6.36 +/- 0.72 mmol/l) and good (MAGE 3.46 +/- 0.66 mmol/l) metabolic control, obtained by means of insulin therapy. Rest values of systolic time intervals were normal during poor and good metabolic control. After exercise, pre-ejection period/left ventricular ejection time ratio increased mainly during poor control as a result of an increased pre-ejection period: conversely, a smaller increase in pre-ejection period/left ventricular ejection time ratio occurred during good metabolic control. The exercise induced free fatty acids utilization did not occur during poor control as it occurred during good control. The percentage of increments in blood lactate was virtually identical in ketotic and non-ketotic patients and in normal subjects. High norepinephrine plasma levels were observed both at rest and during dynamic exercise in poorly controlled diabetic patients. Conclusively, testing of systolic time intervals after exercise might be useful in the detection of preclinical diabetic cardiomyopathy. The decreased cardiac functional reserve observed during poor control might be related to an altered energetic fuel utilization.

The relationship between potassium balance and circulating catecholamines in essential hypertension

A study of neuroendocrine trend and electrolytes balance was carried out in 29 patients with essential hypertension and 20 normotensive controls. Based on plasma norepinephrine (NE) resting values to subgroups of hypertensives were defined, one in the "normal" range (NE less than 268 pg/ml) and one in the "high" range (NE greater than 268 pg/ml). In response to graded exercise the "high" NE hypertensive patients showed a mean NE increase significantly higher than both normal controls and "normal" NE hypertensives (p less than 0.05). No significant differences in the electrolytes excretion rates were found between the two subsets, but only in the hyper-noradrenergic hypertensives a negative correlation between potassium excretion and circulating NE levels was observed (r = -0.68; p less than 0.005). These findings suggest that in the hypertensive population there is a not negligible proportion of patients with elevated NE levels under basal conditions which are, moreover, hyper-responsive to stressful situations. This abnormal sympathetic function could be probably related to the state of potassium balance.