Relationship between blood pressure measured in the clinic and by ambulatory monitoring and left ventricular size as measured by electrocardiogram in elderly patients with isolated systolic hypertension

Age-stratified association of blood pressure with albuminuria and left ventricular hypertrophy in patients with hypertension and diabetes mellitus

PURPOSE

We investigated associations of blood pressure (BP) with albuminuria and left ventricular hypertrophy (LVH) in young, middle and older aged patients with hypertension and/or diabetes mellitus.

MATERIALS & METHODS

Study participants were treated patients with hypertension or diabetes, enrolled in a China nationwide registry. The 2510 patients were classified into young (<45 years, n = 345), middle (45-64 years, n = 1383) and older (≥65 years, n = 782) age groups. Clinic BP was measured three times consecutively on each of the two clinic visits. These six readings were averaged for analyses. Albuminuria was defined as a urinary albumin-to-creatinine ratio of ≥30 mg/g. LVH was assessed by the electrocardiogram (ECG) Cornell product and voltage methods.

RESULTS

The prevalence of albuminuria and ECG-LVH was 17.8 and 6.5%, respectively. Mean (±SD) systolic/diastolic BP was 132.0 ± 16.5/85.2 ± 11.9 mmHg, 136.8 ± 17.9/81.7 ± 11.2 mmHg, and 139.8 ± 16.7/75.8 ± 10.4 mmHg in the young, middle and older age groups. In the young age group, the prevalence of albuminuria increased from 8.8% in systolic/diastolic BP <120/80 mmHg to 14.6, 16.0% and 16.5% in 120-129/80-84, 130-139/85-89 and ≥140/90 mmHg, respectively. The corresponding values were 8.9, 7.0, 18.1 and 22.2%, respectively, in the middle age group, and 21.2, 15.5, 16.4 and 24.4%, respectively, in the older age group. Adjusted analyses confirmed the J-shaped relation between BP and albuminuria in the older but not young age group. The prevalence of ECG-LVH was significantly (p for trend ≤0.04) higher with increasing BP similarly in all age groups.

CONCLUSIONS

The association between BP and organ damage seems to differ in young, middle and older aged patients for albuminuria but not ECG-LVH.

Hypertensive target-organ damage in the very elderly

In people aged >80 years, the so-called very elderly, there is uncertainty about the relation between hypertension and cardiovascular morbidity. The aims of this study were to investigate whether hypertension in people aged >80 years is associated with target-organ damage, over and above the effects of age, and to determine whether ambulatory blood pressure monitoring (ABPM) could improve on conventional blood pressure monitoring (CBPM) in predicting target-organ damage. Investigations included echocardiographic measurement of left ventricular mass index (LVMI), brain magnetic resonance imaging assessment of periventricular hyperintensity (PVH), urinary albumin-creatinine ratio (ACR), aortic pulse wave velocity (PWV), and 24-hour ABPM. Forty-three subjects, at a mean age 84.3 years, were studied, 22 normotensive (NT) and 21 hypertensive (HT). CBP was 184/89 and 145/76 mm Hg in the HT and NT groups, respectively. In men, LVMI was significantly greater in HT subjects, 157+/-37 vs 123+/-15 g/m2 in NT subjects (P<0.05). In women, LVMI was similar in both groups. Urinary ACR was greater in HT than in NT subjects (log ACR, 1.21+/-0.50 vs 0.95+/-0.23; P<0.05). Cerebral PVH grade was higher in the HT subjects (2.6+/-0.8 vs 2.2+/-0.9), although this difference was not significant. Aortic PWV did not differ between the 2 groups. ABPM was positively associated with urinary ACR and cerebral PVH, independent of its correlation with CBPM. In advanced old age, HT is associated with evidence of target-organ damage. ABPM can improve on CBPM in predicting very elderly subjects with HT target-organ damage.

One-year study of felodipine or placebo for stage 1 isolated systolic hypertension

Asubstantial number of older hypertensive patients have stage 1 isolated systolic hypertension (systolic blood pressure between 140 and 159 mm Hg and diastolic blood pressure <90 mm Hg), but there are currently no data showing that drug treatment is effective, safe, and/or beneficial. To compare the effects of active treatment compared with placebo on blood pressure, left ventricular hypertrophy, and quality of life among older stage 1 isolated systolic hypertensive patients, a randomized, double-blind, parallel-group, multicenter clinical trial comparing felodipine (2.5, 5, or 10 mg once daily) and matching placebo was performed in 171 patients (49% male, average age 66+/-7 years, with 49% white and 30% Hispanic) with a baseline blood pressure of 149+/-7/83+/-6 mm Hg. During 52 weeks of treatment, patients randomized to active treatment achieved significantly lower blood pressures (137.0+/-11.7/80.2+/-7.6 mm Hg for extended-release felodipine versus 147.5+/-16.0/83.5+/-9.7 mm Hg for placebo, P<0.01 for each), a reduced incidence of left ventricular hypertrophy (7% for extended release felodipine versus 24% for placebo, P<0.04), and improved quality of life (change in Psychological General Well-Being index, 3.0+/-6.8 for extended-release felodipine versus -0.8+/-10.3 for placebo, P<0.01) versus baseline. There were no clinically significant differences between treatments in tolerability or adverse effects. Stage 1 isolated systolic hypertension can be effectively and safely treated pharmacologically. Treatment reduced progression to the higher stages of hypertension, reduced the incidence of left ventricular hypertrophy, and improved an overall measure of the quality of life. Larger and longer studies will be needed to document any long-term reduction in cardiovascular event rates associated with treating stage 1 systolic hypertension.

Use of ambulatory blood pressure monitoring data to predict left ventricular mass in hypertension

BACKGROUND

Many studies have shown definite but weak correlations between 24h blood pressure and left ventricular mass in hypertension.

OBJECTIVE

The present study applied an original multivariate analysis of parameters from ambulatory blood pressure monitoring to predict left ventricular mass in hypertension.

METHODS

Two hundred untreated hypertensive subjects (age=51+/-13 years, clinic blood pressure=163/98mmHg) had echocardiography and 24h recording of blood pressure. Data from 102 subjects were used to construct a mathematical model for prediction of left ventricular mass. The remaining 98 subjects were used to validate the model.

RESULTS

The model included age, weight, height, 24h systolic blood pressure, heart rate over 24h, standard deviations of systolic blood pressure and of heart rate over 24h. Using this model, we explained 63% of the variance of left ventricular mass. Moreover, the model was validated for the correlation (r=0.70) between measured and the estimated left ventricular mass.

CONCLUSIONS

Systolic blood pressure, heart rate and their standard deviations over 24h contribute to left ventricular mass in hypertensive subjects. Thus, it is important to take into account not only blood pressure but also heart rate in clinical studies.

Electrocardiographic findings in a middle-aged African population in the Seychelles islands

This study describes major electrocardiogram (ECG) measurements and diagnoses in a population of African individuals; most reference data have been collected in Caucasian populations and evidence exists for interethnic differences in ECG findings. This study was conducted in the Seychelles islands (Indian Ocean) and included 709 black individuals (343 men and 366 women) aged 25 to 64 years randomly selected from the general population. Resting ECG were recorded by using a validated ECG unit equipped with a measurement and interpretation software (Cardiovit AT-6, Schiller, Switzerland). The epidemiology of 14 basic ECG measurements, 6 composite criteria for left ventricular hypertrophy and 19 specific ECG diagnoses including abnormal rhythms, conduction abnormalities, repolarization abnormalities, and myocardial infarction were examined. Substantial gender and age differences were found for several ECG parameters. Moreover, tracings recorded in African individuals of the Seychelles differed from those collected similarly in Caucasian populations in many respects. For instance, heart rate was approximately 5 beats per minute lower in the African individuals than in selected Caucasian populations, prevalence of first degree atrio-ventricular block was especially high (4.8%), and the average Sokolow-Lyon voltage was markedly higher in African individuals of the Seychelles compared with black and white Americans. The integrated interpretation software detected "old myocardial infarction" in 3.8% of men and 0% of women and "old myocardial infarction possible" in 6.1% and 3%, respectively. Cardiac infarction injury scores are also provided. In conclusion, the study provides reference values for ECG findings in a specific population of people of African descent and stresses the need to systematically consider gender, age, and ethnicity when interpreting ECG tracings in individuals.

Effect of 24-h blood pressure levels and circadian blood pressure rhythm on left ventricular structure and function in isolated systolic hypertension

Forty-one participants (mean age 69 +/- 5.6 years) were examined by fully automatic blood pressure monitor and Doppler echocardiography to gain information on the ambulatory blood pressure and the left ventricular structure and function in isolated systolic hypertension. Cumulative sum (cusum)-derived statistics was used to quantify circadian blood pressure rhythm and 24-h blood pressure levels were defined as mean blood pressure values during 24 h, waking (06:00-22:00 h) and sleeping (22:00-06:00 h) periods, respectively. Most of the derivatives of ambulatory blood pressure, including cusum-derived statistics and 24-h blood pressure levels, were significantly related with the left ventricular structural (left ventricular posterior wall and interventricular septum thickness) and functional (acceleration time in the left ventricular outflow tract and early diastolic deceleration time) indexes. Among the left ventricular structural and functional indexes, interventricular septum thickness at end diastole had the strongest correlation with sleeping diastolic mean blood pressure (r = 0.41, P < 0.01), left ventricular posterior wall at end diastole, the best with 24-h systolic mean blood pressure (r = 0.41, P < 0.01), acceleration time the strongest with systolic cusum-derived circadian alteration magnitude (r = 0.49, P < 0.01) and early diastolic deceleration time the greatest with diastolic cusum-derived trough blood pressure (r = 0.45, P < 0.01). We conclude that left ventricular structural changes rely on 24-h systolic and diastolic blood pressure levels, whereas left ventricular functional variations may be more dependent upon circadian blood pressure rhythm in elderly patients with isolated systolic hypertension.

Ambulatory blood pressure monitoring

Non-invasive measurement of blood pressure in ambulatory humans began in the 1960s. Ambulatory devices have been modified over the years and are now pocket-sized, with almost noiseless pumps. Their accuracy must be validated by independent laboratories using a standardised protocol. Twenty-four-hour ambulatory monitoring offers considerable advantages over conventional measurement, including avoidance of error associated with conventional measurement, elimination of white-coat effect and the provision of a series of blood pressure readings over the time period rather than a one-off measurement. In clinical practice, 24-hr monitoring provides valuable assistance in both the diagnosis and treatment of hypertension, in particular, in the selection of drug and dosage regimen. In the research setting, 24-hr monitoring plays an important role in establishing dose-response relationships and the duration of action of new drugs. It also has a role in the design of antihypertensive trials by ensuring that those with white-coat hypertension are excluded and by reducing the number of subjects necessary for recruitment. Although 24-hr ambulatory blood pressure is a better predictor of target organ damage, definitive evidence as to whether it is a better predictor of prognosis in hypertension awaits the results of longitudinal studies, which are now underway.