Nurse-recorded and ambulatory blood pressure predicts treatment-induced reduction of left ventricular hypertrophy equally well in hypertension: results from the Swedish irbesartan left ventricular hypertrophy investigation versus atenolol (SILVHIA) study

Circadian blood pressure variation in patients with type 2 diabetes--relationship to macro- and microvascular subclinical organ damage

AIMS

To explore the association between nocturnal blood pressure (BP) dipper status and macro- and microvascular organ damage in type 2 diabetes.

METHODS

Cross-sectional data from 663 patients with type 2 diabetes, aged 55-66 years, were analysed. Nurses measured office BP and ambulatory BP during 24h. Individuals with ≥ 10% difference in nocturnal systolic blood pressure (SBP) relative to daytime values were defined as dippers. Non-dippers were defined as <10% nocturnal decrease in SBP. Estimated glomerular filtration rate (GFR) was calculated and microalbuminuria was measured by albumin:creatinine ratio (ACR). Aortic pulse wave velocity (PWV) was measured with applanation tonometry over the carotid and femoral arteries.

RESULTS

We identified 433 dippers and 230 subjects with a nocturnal non-dipping pattern. Nocturnal SBP dipping was independently of office SBP associated with decreased PWV (p = 0.008), lower ACR (p = 0.001) and NT-proBNP (p = 0.001) and increased GFR (p<0.001).

CONCLUSIONS

We conclude that diurnal BP variation provides further information about early macro- and microvascular subclinical organ damage that goes beyond standardized office BP measurements in patients with type 2 diabetes.

Obesity and daytime pulse pressure are predictors of left ventricular hypertrophy in true normotensive individuals

OBJECTIVE

To investigate predictors of left ventricular mass corrected for height2.7 (LVMI) and left ventricular hypertrophy in patients who were found to be normotensive with both office and 24-h ambulatory blood pressure (BP) measurements.

METHODS

A total of 805 consecutive patients were analyzed. All patients underwent office BP measurements, 24-h ambulatory BP monitoring, laboratory measurements for cardiovascular risk factors and echocardiography. Individuals with both office and ambulatory normotension were characterized as true normotensive.

RESULTS

LVMI was found to be 34.5 +/- 10.9 g/m2.7 in normal-weight patients and 48.7 +/- 13.0 g/m2.7 in obese patients (P < 0.0001). LVMI was found to be 41.7 +/- 10 g/m2.7 in overweight patients, significantly lower than the values of obese patients (P < 0.005) and higher than the values of normal-weight patients (P < 0.001). These results remained significant even after adjustment for age, sex, daytime and nighttime SBP, daytime and nighttime DBP, daytime and nighttime BP variability and daytime and nighttime pulse pressure (PP). In a multivariate analysis model, in which LVMI was the dependent variable and office SBP, office DBP, daytime and nighttime SBP and DBP, daytime and nighttime PPs and variabilities, day-night SBP ratio, fasting serum glucose, triglycerides, total cholesterol, age and BMI were inserted as independent variables with weighted least squares regression by sex, the predictors of LVMI were age, BMI and daytime PP (r2 = 0.31). Left ventricular hypertrophy was 17.67 times more likely in obese patients as compared with normal-weight true normotensive individuals.

CONCLUSION

Obesity may represent a significant cardiovascular risk factor even in normotensive individuals. Other predictors of LVMI were ageing and daytime PP.

The relationship between the plasma concentration of irbesartan and the antihypertensive response is disclosed by an angiotensin II type 1 receptor polymorphism: results from the Swedish Irbesartan Left Ventricular Hypertrophy Investigation vs. Atenolol (SILVHIA) Trial

BACKGROUND

The aim of this study was to investigate the effect of the plasma concentration of irbesartan, a specific angiotensin II type 1 receptor (AT1R) antagonist, and the blood pressure response in relation to AT1R gene polymorphisms.

METHODS

Plasma irbesartan was analyzed in 42 patients with mild-to-moderate hypertension and left ventricular hypertrophy from the Swedish Irbesartan Left Ventricular Hypertrophy Investigation vs. Atenolol (SILVHIA) trial, who were treated with irbesartan as monotherapy for 12 weeks. Blood pressure and irbesartan concentration were measured at trough, i.e., 24 +/- 3 h after the last dose. Five AT1R gene polymorphisms were analyzed by minisequencing.

RESULTS

Neither the plasma concentration of irbesartan, nor any of the AT1R polymorphisms were associated with the blood pressure response to irbesartan treatment. However, the interaction term between the plasma concentration of irbesartan and the AT1R C5245T polymorphism was related to the reduction in systolic blood pressure after 12 weeks of treatment (P = 0.025). Furthermore, the plasma concentration of irbesartan was related to the change in systolic blood pressure in individuals homozygous for the AT1R 5245 T allele (r = -0.56, P = 0.030), but not for other genotypes.

CONCLUSIONS

There was an association between plasma concentrations of irbesartan and the blood pressure response for hypertensive patients with AT1R 5245 TT. Because of the small sample size, this study needs to be viewed as hypothesis generating. This is the first study, to our knowledge, indicating that the concentration-response relationship of an antihypertensive drug may be genotype dependent.

Nurse-recorded clinic and ambulatory blood pressures correlate equally well with left ventricular mass and carotid intima-media thickness

OBJECTIVE

To assess relationships between noninvasive ambulatory blood pressure (BP), clinic BP (mean value of three readings in the seated position measured by nurses), structural cardiac indices, intima-media thickness of the common carotid artery and several hormones.

DESIGN

Cross-sectional study of 75 subjects with hypertension and left ventricular hypertrophy (HTH) according to echocardiography, 35 subjects with hypertension and normal left ventricular dimensions (HT) and 23 normotensive subjects (NT).

RESULTS

We found an excellent correlation between mean 24-h ambulatory BP and clinic BP, the r-value for systolic BP being 0.82 and for diastolic levels 0.78 (both P < 0.0001). Clinic and ambulatory BP correlated equally well with left ventricular (LV) mass index (r-values between 0.55 and 0.64, all P < 0.0001) and to intima-media thickness of the carotid artery (r = 0.18-0.34, P < 0.01). The systolic white-coat effect (clinic BP - day-time BP) was higher in the HTH and HT compared with NT and was weakly correlated to LV mass index (r = 0.18, P = 0.04). Nondippers (mean arterial night/day BP ratio of > 0.9) had higher brain (6.1 +/- 7.5 pmol L(-1) vs. 3.7 +/- 3.2 pmol L(-1), P = 0.01) and atrial (14 +/- 3.4 pmol L(-1) vs. 9.3 +/- 5.4 pmol L(-1), P = 0.04) natriuretic peptide levels, and also exhibited a lower ejection fraction (49 +/- 8% vs. 57 +/- 9%, P = 0.006), than dippers.

CONCLUSION

Clinic BP recordings performed by nurses as three measurements 1 min apart provide excellent relationship to target organ damage. Nondippers exhibited signs of a more advanced hypertensive organ damage than dippers which corresponds well with the poor prognosis linked to this condition.

Hypertension and cardiovascular risk assessment in dialysis patients

INTRODUCTION

Cardiovascular (CV) disease is the main cause of morbidity and mortality in dialysis patients. Hypertension in patients affected by chronic renal insufficiency (CRI) has been recognized as one of the major classical CV risk factors in CRI from the very beginning of the dialysis era. However, its treatment is still unsatisfactory.

METHODS

A discussion is employed to achieve a consensus on key points relating to the epidemiological, pathophysiological and clinical characteristics of hypertension in renal patients, in the light of global CV risk assessment.

RESULTS

CV disease is accelerated by CRI, in particular by uraemia-specific risk factors. This is reflected by the fact that general population-based equations for calculating CV risk underestimate the real CV risk in CRI and dialysis patients. Hypertension in dialysis patients is clearly a major CV risk factor. Isolated systolic hypertension with increased pulse pressure is the most prevalent blood pressure (BP) anomaly in dialysis patients, due to stiffening of the arterial tree. BP should be assessed by clinical measurements on a routine basis, leaving 24 h monitoring for selected cases. The targets of BP control should be those recommended by the present guidelines, i.e. <140/90 mmHg, or the lowest possible values that are well tolerated. The pathophysiological cornerstone of hypertension in dialysis patients is extra-cellular volume expansion, which is typically sodium-sensitive, given the loss of renal function. Therefore, the principles of hypertension treatment in dialysis are an achievement of dry body weight, proper dialysis prescription with respect to dialysis time and intra-dialytic sodium balance, and dietary sodium and water restriction. Pharmacological treatment should only be the second option, after the adequate and complete application of all other means. No comparative pharmacological trials have specifically addressed the issue of hypertension control in dialysis patients. Therefore, this workshop group had to rely largely on data obtained in the general population. Drugs interfering with the renin-angiotensin system were felt to be the first choice, as they have widely been shown to interfere significantly with CV remodelling. Despite long-standing concerns, beta-blockers are being used increasingly even in patients with congestive heart failure and ischaemic cardiomyopathy. Other drug classes may be used in association or as first-line agents according to clinical requirements.

CONCLUSIONS

Hypertension in renal patients has to be given particular and continued attention, and it should be adequately treated in light of the increased CV risk of this patient population. Research into the mechanisms of uraemic cardiomyopathy and cardiovascular remodelling should provide a precious new insight and lead to more precisely targeted and more effective therapies than in the past.

Relationships between left ventricular mass and the renin-angiotensin system, catecholamines, insulin and leptin

OBJECTIVES

Several neurohormonal systems have been suggested to stimulate myocardial cell growth, and thus take part in the development of left ventricular (LV) hypertrophy. We studied associations between LV mass and markers of the renin-angiotensin-aldosterone system (RAAS), the sympathetic nervous system, glucose homeostasis and leptin.

DESIGN

A total of 115 hypertensive patients with LV hypertrophy and two age- and gender-matched control groups consisting of 38 hypertensive patients without LV hypertrophy and 38 normotensive subjects were included. We examined determinants of the RAAS, plasma levels and 24-h urinary excretions of noradrenaline and adrenaline, plasma proinsulin, insulin, glucose, leptin and LV mass by echocardiography.

RESULTS

Plasma renin activity (PRA) and serum aldosterone were higher (both P < 0.001) in the LV hypertrophy group than in patients without LV hypertrophy and normotensive subjects (1.0 +/- 0.8, 0.2 +/- 0.2 and 0.2 +/- 0.2 ng mL(-1) h(-1), and 327 +/- 126, 269 +/- 146 and 221 +/- 80 pmol L(-1), respectively). PRA and aldosterone both related (P < 0.001) to LV mass index (r = 0.44 and 0.27, respectively). Catecholamine levels and excretions were similar in all three groups and did not relate to LV mass index. Proinsulin, insulin and leptin levels were all elevated in the hypertensive patients (P < 0.01), but proinsulin, insulin, insulin sensitivity (by the homeostasis model assessment) and leptin did not relate to LV geometry, when indexed for body size.

CONCLUSIONS

Plasma renin activity and serum aldosterone levels are elevated in hypertensive LV hypertrophy and relate to LV mass index. In addition to blood pressure, activation of the RAAS may be an important nonhaemodynamic mechanism in the control of LV hypertrophy.