Contemporary management of refractory hypertension

Quadriceps short-term resistance exercise in subjects with resistant hypertension

INTRODUCTION: Resistant arterial hypertension may lead to muscle disuse and reduced functional capacity due to arterial and target-organs lesions. The main objective of this work is to evaluate the quadriceps strength and fatigue tolerance after a program of resistance exercise in subjects with resistant primary hypertension. METHODS: Six patients under pharmacological treatment were submitted to a four-week resistance exercise training program for the quadriceps (8-14 repetitions, 3 sets, 3 days per week). Strength was evaluated by isometric dynamometry, as the percentage change in maximum voluntary contraction over the four week program. Fatigue was analyzed by surface electromyography, as the change in both root mean square value and intercept of median frequency slope of vastus medialis and vastus lateralis. RESULTS: Significant increase in the maximum voluntary contraction was observed (p = 0.04). Fatigue tolerance was not improved as seen by root mean square as well as in the intercept of median frequency (p > 0.05). Additionally, no significant changes were observed in resting arterial blood pressure and heart rate throughout the training period. CONCLUSION: The prescribed protocol seemed to successfully increase localized muscle strength without negatively affecting the monitored cardiovascular variables in patients with resistant hypertension under pharmacological treatment.

Resistant hypertension workup and approach to treatment

Resistant hypertension is defined as blood pressure above the patient's goal despite the use of 3 or more antihypertensive agents from different classes at optimal doses, one of which should ideally be a diuretic. Evaluation of patients with resistive hypertension should first confirm that they have true resistant hypertension by ruling out or correcting factors associated with pseudoresistance such as white coat hypertension, suboptimal blood pressure measurement technique, poor adherence to prescribed medication, suboptimal dosing of antihypertensive agents or inappropriate combinations, the white coat effect, and clinical inertia. Management includes lifestyle and dietary modification, elimination of medications contributing to resistance, and evaluation of potential secondary causes of hypertension. Pharmacological treatment should be tailored to the patient's profile and focus on the causative pathway of resistance. Patients with uncontrolled hypertension despite receiving an optimal therapy are candidates for newer interventional therapies such as carotid baroreceptor stimulation and renal denervation.

An Implantable Carotid Sinus Baroreflex Activating System: Surgical Technique and Short-Term Outcome from a Multi-Center Feasibility Trial for the Treatment of Resistant Hypertension

OBJECTIVES

To assess perioperative outcomes and blood pressure (BP) responses to an implantable carotid sinus baroreflex activating system being investigated for the treatment of resistant hypertension.

METHODS

We report on the first seventeen patients enrolled in a multicenter study. Bilateral perivascular carotid sinus electrodes (CSL) and a pulse generator (IPG) are permanently implanted. Optimal placement of the CSL is determined by intraoperative BP responses to test activations. Acute BP responses were tested postoperatively and during the first four months of follow-up.

RESULTS

Prior to implant, BP was 189.6+/-27.5/110.7+/-15.3 mmHg despite stable therapy (5.2+/-1.8 antihypertensive drugs). The mean procedure time was 202+/-43 minutes. No perioperative strokes or deaths occurred. System tests performed 1 or up to 3 days postoperatively resulted in significant (all p < or = 0.0001) mean maximum reduction, with standard deviations and 95% confidence limits for systolic BP, diastolic BP and heart rate of 28+/-22 (17, 39) mmHg, 16+/-11 (10, 22) mmHg and 8+/-4 (6, 11) BPM, respectively. Repeated testing during 3 months of therapeutic electrical activation demonstrated a durable response.

CONCLUSIONS

These preliminary data suggest an acceptable safety of the procedure with a low rate of adverse events and support further clinical development of baroreflex activation as a new concept to treat resistant hypertension.

Resistant hypertension: diagnosis and management

The incidence of resistant hypertension, the failure to reduce blood pressure below 140/90 mm Hg, despite the use of 3 antihypertensive medications at optimal doses including a diuretic, is estimated to be less than 5% of the hypertensive population. Resistant hypertension increases the risk of stroke, myocardial infarction, congestive heart failure, and renal failure. Evaluation of the patient with resistant hypertension should include 24-hour ambulatory blood pressure monitoring or home measurements and a limited search for secondary causes. Treatment should focus on optimizing the drug regimen in a logical way, based on the patient's comorbidities and tolerability. Long-acting, well-tolerated once-daily medications are preferred, and the regimen should include in sequence a diuretic, beta-blocker, angiotensin-converting enzyme/angiotensin receptor-blocker inhibitors, and a calcium-channel blocker. This article reviews the definitions and causes and provides specific recommendations for the evaluation and management of patients with this life-threatening condition.

Resistant hypertension, secondary hypertension, and hypertensive crises

Resistant hypertension, secondary hypertension, and hypertensive crises are uncommon but potentially dangerous forms of hypertension that are associated with an increased risk of complications such as myocardial infarction, heart failure, stroke, and renal failure. Appropriate diagnostic screening and selective drug or surgical management can reduce the risk of these complications dramatically. In compliant patients, resistant hypertension occurs most often in obese patients receiving inadequate diuretic therapy. In patients with clinical clues to the diagnosis, the best current screening test for renovascular hypertension is probably the ACE-inhibitor renal scintiscan. Angioplasty is considerably more successful in younger patients with fibrous dysplasia than in older patients with the atherosclerotic variety. Hypertensive crises are divided into BP urgencies and emergencies. In both settings, the reduction in BP should generally be gradual rather than abrupt, with no intent to acutely normalize the BP.

Efficacy of eprosartan in combination with HCTZ in patients with essential hypertension

This randomised, double-blind study was designed to investigate the efficacy of a once-daily (OD) combination of the AT(1) receptor blocker, eprosartan 600 mg, and the thiazide diuretic, hydrochlorothiazide (HCTZ) 12.5 mg, in patients with mild to moderate hypertension (sitting diastolic blood pressure (sitDBP) > or =98 mm Hg and < or =114 mm Hg) not adequately controlled with eprosartan 600 mg OD. A total of 494 patients entered the open-label monotherapy run-in phase, which consisted of eprosartan 600 mg OD for 3 weeks. Patients who responded to monotherapy were not eligible to enter the randomised phase of the study and were withdrawn. The remaining 309 patients were then randomised to either eprosartan 600 mg plus HCTZ 12.5 mg OD or to continue on eprosartan 600 mg OD. In the eprosartan plus HCTZ combination group, both sitDBP and sitting systolic blood pressure (sitSBP) were significantly reduced compared with the eprosartan monotherapy group. In addition, the response rate was higher in the combination group compared with the monotherapy group. There were no significant effects on reduction of sitDBP due to gender, prior use of antihypertensives or baseline severity of hypertension. The tolerability profile for the combination group was similar to that for the monotherapy group. Headache was the most frequent adverse event in both treatment groups. The majority of adverse events were mild to moderate in intensity. In this study of patients who were unresponsive to eprosartan monotherapy for 3 weeks, a combination product of eprosartan 600 mg and HCTZ 12.5 mg was shown to be an effective and well tolerated treatment.

Factors influencing the systolic blood pressure response to drug therapy

In the early stage of hypertension, diastolic blood pressure has greater prognostic importance, but in the elderly, systolic blood pressure is the most important marker of cardiovascular complications. Therefore, the need for more strict control of this component of blood pressure must be reconsidered. The benefit obtained in different studies in the elderly suggests that the treatment of isolated systolic hypertension is associated with a reduction in overall cardiovascular mortality of 22%, in coronary heart disease mortality of 26%, and in stroke mortality of 33%. However, a higher percentage of patients (73%) attain the diastolic goal of <90 mm Hg, while only 34% have systolic pressure reduced to <140 mm Hg. In a review of randomized trials comparing at least four different antihypertensive drugs, significant differences in systolic blood pressure reduction have not been demonstrated, except in black populations, in whom calcium channel blockers and diuretics seem to be more effective. In patients with isolated systolic hypertension, data are inconclusive, but calcium channel blockers and diuretics appear to lower blood pressure to a greater degree than do other antihypertensive drugs. Two main predictors of difficulty in controlling systolic blood pressure are the baseline blood pressure and the presence of diabetes. Other predictors are the duration of arterial hypertension, older age, the presence of target organ damage and associated clinical conditions (myocardial infarction, stroke, chronic renal failure), and an elevated serum uric acid level. It appears that the profile of patients with a poorer therapeutic response includes a greater severity of hypertension and/or the presence of cardiovascular disease.

High prevalence of cardiac and extracardiac target organ damage in refractory hypertension

OBJECTIVE

Target organ damage (TOD) in chronically treated hypertensives is related to effective blood pressure (BP) control. The aim of this study was to evaluate the prevalence of cardiac and extracardiac TOD in patients with refractory hypertension (RH) compared with well-controlled treated hypertensives (C).

METHODS

Fifty-four consecutive patients with RH (57 +/- 10 years), selected according to WHO/ISH guidelines definition, and 51 essential hypertensives (55 +/- 10 years) with satisfactory BP control obtained by association therapy, underwent the following procedures: (1) clinic BP measurement; (2) blood sampling for routine chemistry examinations; (3) 24 h urine collection for microalbuminuria; (4) non-mydriatic retinography; (5) echocardiogram; (6) carotid ultrasonogram. In order to exclude 'office resistance' (defined as clinic BP > 140/90 mmHg and average 24 h BP </= 125/79 mmHg), all patients with RH were subjected to 24-hour ambulatory BP monitoring.

RESULTS

Both groups were similar for age, gender, body surface area, smoking habit and duration of hypertension, glucose, creatinine and lipid levels. By definition, clinic BP was significantly higher in RH than C (161 +/- 19/96 +/- 9 versus 127 +/- 6/80 +/- 5 mmHg, respectively, P < 0.01). The increased prevalence of left ventricular hypertrophy (LVH) and carotid intima-media (IM) thickening (40 versus 12%, P < 0.01, according to a non-gender-specific partition value of 125 g/m2; and 36 versus 14%, P < 0.01, according to IM thickness > or =1.0 mm, respectively); a higher prevalence of carotid plaques (65 versus 32%, P < 0.05), a more advanced retinal involvement (grade II and III, 73 and 5% versus 38 and 0%, P < 0.01) and a greater albumin urinary excretion (22 +/- 32 mg/24 h versus 11 +/- 13 mg/24 h, P < 0.01) were found in RH compared to C.

CONCLUSIONS

Our study suggests that RH is a clinical condition associated with a high prevalence of TOD at cardiac, macro- and microvascular level and consequently with high absolute cardiovascular risk, which needs a particularly intensive therapeutic approach aimed to normalize BP levels and to induce TOD regression.