Lifestyle modification may have an impact on morbidity and mortality. A diet rich in fruits, vegetables, and low-fat dairy foods and low in saturated and total fats (DASH diet) has been shown to lower blood pressure. Additional measures can prevent or mitigate hypertension or its cardiovascular consequences as shown in Table 11-2.
All patients with high-normal or elevated blood pressures, those who have a family history of cardiovascular complications of hypertension, and those who have multiple coronary risk factors should be counseled about nonpharmacologic approaches to lowering blood pressure. Approaches of proved but modest value include weight reduction, reduced alcohol consumption and, in some patients, reduced salt intake. Gradually increasing activity levels should be encouraged in previously sedentary patients, but strenuous exercise training programs in already active individuals may have less benefit. Calcium and potassium supplements have been advocated, but their ability to lower blood pressure is limited.
Smoking cessation will reduce overall cardiovascular risk.
Bray GA et al: A further subgroup analysis of the effects of the DASH diet and three dietary sodium levels on blood pressure: results of the DASH-Sodium Trial. Am J Cardiol 2004;94:222. [PMID: 15246908] Hooper L et al: Advice to reduce dietary salt for prevention of cardiovascular disease. Cochrane Database Syst Rev 2004;(1): CD003656. [PMID: 14974027] Krousel-Wood MA et al: Primary prevention of essential hypertension. Med Clin North Am 2004;88:223. [PMID: 14871061] Stewart KJ: Exercise training and the cardiovascular consequences of type 2 diabetes and hypertension: plausible mechanisms for improving cardiovascular health. JAMA 2002;288:1622. [PMID: 12350193] Whelton SP et al: Effect of aerobic exercise on blood pressure: a meta-analysis of randomized controlled trials. Ann Intern Med 2002;136:493. [PMID: 11926784] Wilburn AJ et al: The natural treatment of hypertension. J Clin Hypertens (Greenwich) 2004;6:242. [PMID: 15133406]
Who Should Be Treated with Medications?
Many excellent trials have shown that drug therapy of patients with stage 2 hypertension reduces the incidence of stroke by 30-50%, congestive heart failure by 40-50%, and progression to accelerated hypertension syndromes. The decreases in fatal and nonfatal coronary heart disease and cardiovascular and total mortality have been less dramatic, ranging from 10% to 15%. This lesser decrease in coronary heart disease has generated controversy. Some experts have attributed the decreased benefit to characteristics of the drugs (primarily diuretics and β-blockers), such as their adverse effect on lipid profiles and electrolyte balance. Others believe it is due to the more chronic and multifactorial nature of coronary artery disease, the generally low-risk populations included in trials, and the large number of crossovers from placebo to active therapy. Several studies in older persons with predominantly systolic hypertension have confirmed that antihypertensive therapy prevents fatal and nonfatal myocardial infarction and overall cardiovascular mortality. These trials have also placed the focus on control of systolic blood pressure - in contrast to the historical emphasis on diastolic blood pressures.
The decision to initiate drug therapy is relatively straightforward once hypertension has been unequivocally diagnosed (Table 11-1 and Figure 11-1), but less clear in persons with prehypertension (blood pressure of 120-139/80-89 mm Hg). In the latter group, treatment decisions should be based on an assessment of overall cardiovascular risk rather than the level of blood pressure alone. The JNC criteria for institution of therapy (Table 11-1) suggest that patients with prehypertension should be treated if they exhibit at least one additional high-risk condition with compelling indications (listed in Table 11-4), such as chronic kidney disease or diabetes mellitus. In the presence of compelling indications, the target blood pressure should be < 130/80 mm Hg in persons with prehypertension just as in those with hypertension. Table 11-5 lists the major risk factors for cardiovascular morbidity and mortality and the cardiovascular manifestations that predispose to further complications. The BHS promotes a similar approach but goes further by introducing a consideration of overall predicted cardiovascular risk (
Figure 11-2). According to the BHS recommendations, risk analysis should be used to target treatment to patients with borderline hypertension who are most likely to benefit, particularly individuals at high combined risk of coronary heart or stroke event (> 20-30% within 10 years). A risk calculation tool can be downloaded from the BHS web site at http://www. bhsoc.org/Cardiovascular_Risk_Charts_and_Calculators. htm (in using this tool, convert cholesterol from mmol/L to mg/dL by multiplying by 38.7). A free PDA-based coronary heart disease risk calculator is available at http://www.statcoder.com/cholesterol.htm. In general, 20% total cardiovascular risk (which includes stroke) is equivalent to 15% coronary heart disease risk.
Figure 11-2British Hypertension Society algorithm for diagnosis and treatment of hypertension, incorporating total cardiovascular risk in deciding which “prehypertensive” patients to treat. (CVD = cardiovascular disease.) (Reproduced with permission from: Guidelines for management of hypertension: report of the Fourth Working Party of the British Hypertension Society, 2004-BHS IV. J Hum Hypertens 2004;18:139-185.)