Beyond the usual strategies for blood pressure reduction: therapeutic considerations and combination therapies

Current and Future Treatment of Hypertension in the SPRINT Era

Based on the SPRINT trial, it is highly likely that new SPRINT-era guidelines will establish a blood pressure (BP) goal of < 130/80 mm Hg for those aged 50 or older who are at high risk for a cardiovascular event. In this group, SPRINT demonstrated that assignment to an intensive-treatment systolic BP (SBP) goal of < 120 mm Hg significantly reduced cardiovascular events and mortality compared to those assigned to a standard-treatment SPB goal of < 140 mm Hg. This review critically assesses current hypertension guidelines and presents predictions for SPRINT-era guidelines in the elderly, African Americans, and patients with uncomplicated essential hypertension, diabetes, chronic kidney disease, cardiovascular disease, and coronary artery disease. Specific attention is paid to BP goals and preferred pharmacological antihypertensive therapy in these populations, and an algorithm that incorporates the SPRINT trial results is presented. Inhibitors of the renin-angiotensin-aldosterone system as well as calcium channel blockers are universally accepted as first-line therapy in uncomplicated hypertension, but controversy exists over the role of thiazide diuretics and beta blockers. This review also discusses a physiologically and outcomes-based approach to combination therapy for treatment of hypertension.

Controversies in blood pressure goal guidelines and masked hypertension

In uncomplicated hypertension, <140/90 mmHg is the treatment goal for individuals aged 18-79 and between 140 mmHg and 150 mmHg in those 80 years of age. Inhibitors of the renin-angiotensin-aldosterone system, as well as calcium channel blockers, are universally accepted as first-line therapy in uncomplicated hypertension, but controversy exists over the role of thiazide diuretics and beta blockers. Because at similar blood pressure (BP) levels, African Americans have more target organ damage than whites, a lower goal of <135/85 mmHg is recommended. In patients with coronary artery disease, diabetes, and chronic kidney disease, <130/80 mmHg is recommended. Masked hypertension, defined as normal clinic BP with a high average self-monitored or ambulatory BP, is prevalent in those with chronic kidney disease, diabetes, and obstructive sleep apnea. Masked hypertension is associated with worse outcome. Ambulatory BP monitoring for those at risk for masked hypertension needs to be incorporated into guidelines.

Renovascular hypertension update

Hypertension detected in patients with renovascular disease poses a major clinical challenge. The rapid expansion of noninvasive imaging, effective antihypertensive drug therapy, and endovascular interventional procedures combine to make optimal management a moving target. Renal arterial disease accelerates the development of hypertension associated with activation of multiple pressor systems and accelerated target organ injury. Younger individuals with fibromuscular lesions often respond well to renal revascularization with minor associated risks. Care must be taken in cases of complex vascular anomalies, such as renal artery aneurysms. Atherosclerotic renal artery stenosis is detected more commonly than ever before and affects more than 85% of patients referred for revascularization. Most are older patients with long-standing hypertension, diabetes, and pre-existing complications of vascular disease. The benefits of extensive workup and intervention in this group of patients are controversial. Antihypertensive drug therapy is most effectively achieved with drugs that block the renin-angiotensin system, but most require multiple agents. Selection of patients for renal revascularization in this group is far more controversial than with fibromuscular disease. Several small trials failed to identify major benefits with renal artery angioplasty as compared to closely monitored drug therapy, although crossover rates from medical to interventional arms were high. The Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL) seeks to randomly assign subjects with proven, high-grade renal artery lesions to optimal medical management with and without stenting. This important trial employs distal embolic protection to prevent deterioration of renal function. Understanding the optimal role for renal revascularization depends heavily upon the successful conduct of such trials.

Treatment of resistant hypertension

Although the true prevalence of resistant hypertension is not known, it is likely that this condition will become increasingly common, driven by an aging population, obesity, nonadherence trends, and effects of target-organ disease. Current approaches focus on two goals: evaluation and correction of contributing causes, then selection of an effective drug regimen. Lifestyle factors contribute to resistance, particularly high sodium intake and weight gain. Secondary causes should be considered and corrected if feasible. Recent efforts have focused on the development of clinical pathways to guide treatment, based on plasma renin activity, aldosterone production, or hemodynamic measurements. The components of drug combinations beyond the second agent remain empiric. Although volume expansion plays a key role in drug resistance, clinical assessment of volume status is often difficult, frustrating efforts to achieve blood pressure control. Determination of the most effective approaches will require clinical trials using combination therapy.

Clinical efficacy and safety of telmisartan 80 mg once daily compared with enalapril 20 mg once daily in patients with mild-to-moderate hypertension: results of a multicentre study

The efficacy and safety of once-daily telmisartan 80 mg vs. once-daily enalapril 20 mg in the treatment of essential hypertension were evaluated in a multicentre, single-blind, placebo-controlled, randomised trial. In total, 68 patients (49 females, 19 males) with mild-to-moderate hypertension, defined as morning supine systolic blood pressure (SBP) 141-149 mmHg, diastolic blood pressure (DBP) 95-114 mmHg, were enrolled. After a 4-week placebo run-in phase, patients were randomly assigned to treatment with telmisartan or enalapril administered once daily in the morning for 8 weeks. No statistically significant differences were found in the baseline characteristics of patients in either group. Both SBP and DBP were decreased in both treatment groups, but the reductions were statistically different in favour of telmisartan (SBP, p = 0.013; DBP, p = 0.002). The incidence of adverse effects was lower in the telmisartan group, with the absence of cough. In conclusion, telmisartan is more effective and better tolerated than enalapril for the treatment of hypertension and has the advantage that it does not cause cough.

Prescribing patterns of diuretics in multi-drug antihypertensive regimens

Recent literature suggests that most hypertensives will require two or more drugs to achieve target blood pressure. Our objective was to estimate the proportion of patients receiving diuretics, including thiazides, for blood pressure control among those receiving two or more drugs. We studied 25,052 hypertensives in a tertiary care Veterans Affairs facility and identified individuals taking any thiazide or loop diuretic among patients receiving two, three, four, or more drugs. Rates of any diuretic use were 50%, 73%, and 89%, and decreased to 39.0%, 59.0%, and 72.5% for thiazide use, respectively. Rates of thiazide use were statistically significantly higher among African Americans compared with the general study population, but did not differ significantly in the elderly. Though overall diuretic use seems to be increasing as compared with previous studies, there is room for improvement in the use of thiazides in multi-drug hypertension regimens.

Effect of Blood Pressure on Early Decline in Kidney Function Among Hypertensive Men

Few cohort studies have examined the longitudinal association between change in blood pressure and decline in kidney function among treated hypertensive patients without chronic kidney disease. We conducted a nonconcurrent cohort study to examine the effects of blood pressure on estimated glomerular filtration rate and early kidney function decline (rise in serum creatinine > or =0.6 mg/dL during follow-up) among 504 African-American and 218 white hypertensive patients. Our results showed that each standard deviation higher treated systolic (18 mm Hg) and diastolic (10 mm Hg) blood pressure was associated with an average annual decline (95% confidence interval [CI]) in estimated glomerular filtration rate of -0.92 ([-1.49 to -0.36] P=0.001) and -0.83 ([-1.38 to -0.28] P=0.003) mL x min(-1) x 1.73 m(-2), respectively, after adjustment for race, age, education, income, use of antihypertensive drugs, body mass index, and history of diabetes and dyslipidemia. Likewise, each standard deviation higher systolic and diastolic blood pressure was associated with relative risks (95% CIs) of 1.81 ([1.29 to 2.55] P<0.001) and 1.55 ([1.08 to 2.22] P=0.046), respectively, for early kidney function decline. Compared with patients with a blood pressure level <140/90 mm Hg, those with a blood pressure level > or =160/95 mm Hg had a -2.67 ([-4.01 to -1.32] P<0.001) mL x min(-1) x 1.73 m(-2) greater annual decline in estimated glomerular filtration rate and a 5.21-fold ([2.06 to 13.21] P<0.001) greater risk of early kidney function decline. Our study found that higher levels of treated blood pressure were positively and significantly related to early decline in kidney function among hypertensive men. These results indicate that better blood pressure control might prevent the onset of chronic kidney disease among hypertensives.

Rationale for combination therapy as initial treatment for hypertension

Recent hypertension guidelines recommend initiating antihypertensive therapy with a combination of two or more agents in patients whose blood pressure exceeds their appropriate blood pressure goal by 20/10 mm Hg. This recommendation is based on the knowledge that the majority of patients with blood pressures of this magnitude will not achieve sufficient blood pressure reduction with monotherapy. Further, compared with high-dose monotherapy, combination therapy is often associated with fewer adverse effects and, for this reason, may improve patient adherence. Bringing patients to blood pressure goal quickly is likely to improve clinical outcomes. This article discusses the rationale for using combination antihypertensive therapy as initial therapy for high blood pressure in selected patients and reviews data from a study of 364 high-risk patients with Stage 2 hypertension in which a fixed-dose combination product (amlodipine besylate/benazepril HCl) proved more successful as initial therapy than high-dose monotherapy (amlodipine besylate) in reducing blood pressure.

The economic impact of hypertension

High blood pressure is the most common chronic medical problem prompting visits to primary health care providers, yet it is estimated that only 34% of the 50 million American adults with hypertension have their blood pressure controlled to a level of <140/90 mm Hg. Thus, about two thirds of Americans with hypertension are at increased risk for cardiovascular events. The medical, economic, and human costs of untreated and inadequately controlled high blood pressure are enormous. Adequate management of hypertension can be hampered by inadequacies in the diagnosis, treatment, and/or control of high blood pressure. Health care providers face many obstacles to achieving blood pressure control among their patients, including a limited ability to adequately lower blood pressure with monotherapy and a typical reluctance to increase therapy (either in dose or number of medications) to achieve blood pressure goals. Patients also face important challenges in adhering to multidrug regimens and accepting the need for therapeutic lifestyle changes. Nonetheless, the achievement of blood pressure goals is possible, and, most importantly, lowering blood pressure significantly reduces cardiovascular morbidity and mortality, as proved in clinical trials. The medical and human costs of treating preventable conditions such as stroke, heart failure, and end-stage renal disease can be reduced by antihypertensive treatment. The recurrent and chronic morbidities associated with hypertension are costly to treat. Pharmacotherapy for hypertension therefore offers a substantial potential for cost savings. Pharmacoeconomic analyses regarding antihypertensive drug therapies, their costs, and the relevant reductions in health care expenditures are a useful framework for optimizing current strategies for hypertension management.