Impact of blood pressure and blood pressure change during middle age on the remaining lifetime risk for cardiovascular disease: the cardiovascular lifetime risk pooling project

Background Prior estimates of lifetime risk (LTR) for cardiovascular disease (CVD) examined the impact of blood pressure (BP) at the index age and did not account for changes in BP over time. We examined how changes in BP during middle age affect LTR for CVD, coronary heart disease, and stroke. Methods and Results Data from 7 diverse US cohort studies were pooled. Remaining LTRs for CVD, coronary heart disease, and stroke were estimated for white and black men and women with death free of CVD as a competing event. LTRs for CVD by BP strata and by changes in BP over an average of 14 years were estimated. Starting at 55 years of age, we followed up 61 585 men and women for 700 000 person-years. LTR for CVD was 52.5% (95% confidence interval, 51.3-53.7) for men and 39.9% (95% confidence interval, 38.7-41.0) for women. LTR for CVD was higher for blacks and increased with increasing BP at index age. Individuals who maintained or decreased their BP to normal levels had the lowest remaining LTR for CVD, 22% to 41% , compared with individuals who had or developed hypertension by 55 years of age, 42% to 69%, suggesting a dose-response effect for the length of time at high BP levels. Conslusions Individuals who experience increases or decreases in BP in middle age have associated higher and lower remaining LTR for CVD. Prevention efforts should continue to emphasize the importance of lowering BP and avoiding or delaying the incidence of hypertension to reduce the LTR for CVD.     

Central aortic blood pressure assessment and cardiovascular risk

Peripheral brachial blood pressure measurements may not provide an accurate representation of degenerative changes that characterize cardiovascular disease. Evidence is mounting that antihypertensive treatment strategies with apparently similar effects on brachial blood pressure may have different effects on central aortic pressure, which in turn may lead to overestimation or underestimation of therapeutic efficacy. The relative importance of central and brachial blood pressure for predicting cardiovascular risk and clinical outcomes has been examined in several clinical studies. These studies have reported that a large proportion of individuals considered to have normal blood pressure values based on brachial systolic pressures had high-normal blood pressure based on central aortic pressure measurements. As additional evidence suggesting the superiority of central aortic pressure over peripheral assessments becomes more abundant, measurement of central aortic pressure may be the next important advancement in the management of hypertension.     

Elevated systolic blood pressure as a cardiovascular risk factor

This paper reviews the evolution of attitudes toward the treatment and diagnosis of hypertension. In particular, there is a growing realization that elevated systolic pressure may be a more valuable measurement in evaluating and controlling hypertension than is generally acknowledged. A large number of epidemiologic studies in a wide variety of populations have revealed that systolic blood pressure exerts a stronger influence than diastolic blood pressure. The largest of these, the Framingham Heart Study, showed that in subjects with systolic hypertension, diastolic blood pressure was only weakly related to the risk of cardiovascular events, but in those with diastolic hypertension, the risk of these events was strongly influenced by the level of systolic pressure. Furthermore, cardiovascular event rates were found to increase steeply with systolic pressure and were higher in cases of isolated systolic hypertension than diastolic hypertension. Clinical trials produced similar results, again suggesting that a greater reliance should be placed on systolic pressure in evaluating the risk of cardiovascular problems. This review concludes that the health community needs to be reeducated to consider the importance of systolic and diastolic blood pressure in assessing appropriate management strategies for hypertensive patients.     

The importance of diastolic blood pressure in predicting cardiovascular risk

Brachial systolic blood pressure (SBP) is the overall best predictor of future cardiovascular risk for the entire hypertensive population; however, there is much that can be learned from assessing diastolic blood pressure (DBP) in relation to simultaneous levels of SBP, because the former is not distorted by pressure amplification. Low DBP in very young adults (mean age 20 years), presenting as isolated systolic hypertension (ISH), results from elevation in stroke volume and/or arterial stiffness. This subtype of hypertension has a marked male predominance, occurs twice as frequently as essential hypertension, and is potentially not a benign condition. In contrast, isolated diastolic hypertension (IDH) in young adults (mean age of 40 years) with IDH occurs predominantly in men with a high prevalence of metabolic syndrome. Indeed, persons with IDH frequently evolve into systolic-diastolic hypertension and are potentially at increased risk for future diabetes and cardiovascular complications. The older age population with ISH and low DBP (mean age ≥60 years of age) has a high prevalence of left ventricular hypertrophy, increased ventricular-arterial stiffness, and a tendency for diastolic dysfunction and heart failure. Finally, concordant very high DBP, especially in older persons, defines potential hypertensive urgencies, emergencies, secondary forms of hypertension, and other high peripheral resistance states.     

Ambulatory blood pressure and cardiovascular risk in chronic kidney disease

Diagnosis of hypertension is critically dependent on accurate blood pressure (BP) measurement, especially in patients with chronic kidney disease (CKD), in whom early antihypertensive treatment is imperative to prevent cardiovascular events. Ambulatory BP monitoring (ABPM) has successfully identified hypertensive patients at increased risk, but its role in management of CKD patients is not well defined. Loss of the nocturnal decline in BP, which is common in CKD, is associated with adverse cardiovascular events. Increased BP variability has been documented as related to worse outcome, and patients on dialysis are subject to marked BP swings. Traditional measurement in the office fails to provide a thorough picture of the 24-hour BP pattern in CKD patients. Thus, ABPM appears mandatory to better define the hypertensive status in these subjects because it provides information on diurnal BP rhythm and variability and allows identification of subjects with white-coat and masked hypertension.     

High blood pressure and associated cardiovascular risk factors in France

OBJECTIVE: To estimate, with respect to age and gender, the prevalence of high blood pressure (BP) in treated and non-treated subjects and its association with other cardiovascular risk factors. DESIGN: A cross-sectional study. SETTING: Healthcare centres in the centre of France. PARTICIPANTS: All subjects (n = 61,108) who had a free health check-up, between February 1995 and September 1996. MAIN OUTCOME MEASURES: High BP (systolic blood pressure (SBP) > 140 mmHg, diastolic blood pressure (DBP) > 90 mmHg or antihypertensive therapy); diabetes (fasting glucose plasma concentration > 1.26 g/l or antidiabetic therapy); hypercholesterolaemia (total cholesterol > 2 g/l or lipid-lowering therapy); hypertriglyceridaemia (fasting triglycerides plasma concentration > 2 g/l or triglyceridaemia-lowering therapy); overweight (body mass index >or= 25 kg/m2); abdominal fat distribution (waist to hip ratio > 0.9 in males and > 0.8 in females). RESULTS: Prevalence of high BP was 37.7% in males and 22.2% in females. BP was normalized in 29.7% of treated males and 44.1% of treated females. High BP was associated with at least another cardiovascular risk factor in 83.8% of the males and 76.7% of the females with high BP. Hypercholesterolaemia was the most frequently associated risk factor. Except smoking, the prevalence of each cardiovascular risk factor was shown to increase with the severity of hypertension. Two or more other cardiovascular risk factors were present in 22.9% of the males and 9.8% of the females with high BP. CONCLUSIONS: Rate of high BP, even in treated subjects, is high. More than three out of four subjects with high BP have at least one other cardiovascular risk factor.     

Diagnostic thresholds for ambulatory blood pressure monitoring based on 10-year cardiovascular risk

Current diagnostic thresholds for ambulatory blood pressure (ABP) mainly rely on statistical parameters derived from reference populations. We determined an outcome-driven reference frame for ABP measurement. We performed 24-h ABP monitoring in 5682 participants (mean age 59.0 years; 43.3% women) enrolled in prospective population studies in Copenhagen, Denmark; Noorderkempen, Belgium; Ohasama, Japan; and Uppsala, Sweden. In multivariate analyses, we determined ABP thresholds, which yielded 10-year cardiovascular risks similar to those associated with optimal (120/80 mmHg), normal (130/85 mmHg), and high (140/90 mmHg) blood pressure on office measurement. Over 9.7 years (median), 814 cardiovascular end points occurred, including 377 strokes and 435 cardiac events. Systolic/diastolic thresholds for optimal ABP were 118.3/74.2 mmHg for 24 h, 121.6/78.9 mmHg for daytime, and 104.7/65.3 mmHg for nighttime. Corresponding thresholds for normal ABP were 124.3/76.8, 129.9/82.6, and 111.6/68.1 mmHg, respectively, and those for ambulatory hypertension were 130.3/79.4, 138.2/86.4, and 118.5/70.8 mmHg. After rounding, approximate thresholds for optimal ABP amounted to 115/75 mmHg for 24 h, 120/80 mmHg for daytime, and 105/65 mmHg for nighttime. Rounded thresholds for normal ABP were 125/75, 130/85, and 110/70 mmHg, respectively, and those for ambulatory hypertension were 130/80, 140/85, and 120/70 mmHg. In conclusion, population-based outcome-driven thresholds for optimal and normal ABP are lower than those currently proposed by hypertension guidelines.