Blood-pressure lowering for the secondary prevention of stroke

Short-term blood pressure variability - variation between arm side, body position and successive measurements: a population-based cohort study

Background

Precise blood pressure (BP) measurements are central for the diagnosis of hypertension in clinical and epidemiological studies. The purpose of this study was to quantify the variability in BP associated with arm side, body position, and successive measurements in the setting of a population-based observational study. Additionally, we aimed to evaluate the influence of different measurement conditions on prevalence of hypertension.

Methods

The sample included 967 men and 812 women aged 45 to 83 years at baseline. BP was measured according to a standardized protocol with oscillometric devices including three sitting measurements at left arm, one simultaneous supine measurement at both arms, and four supine measurements at the arm with the higher BP. Hypertension was defined as systolic BP (SBP) ≥140 mmHg and/or diastolic BP (DBP) ≥90 mmHg. Variability in SBP and DBP were analysed with sex-stratified linear covariance pattern models.

Results

We found that overall, no mean BP differences were measured according to arm-side, but substantial higher DBP and for men also higher SBP was observed in sitting than in supine position and there was a clear BP decline by consecutive measurement. Accordingly, the prevalence of hypertension depends strongly on the number and scheme of BP measurements taken to calculate the index values.

Conclusions

Thus, BP measurements should only be compared between studies applying equal measurement conditions and index calculation. Moreover, the first BP measurement should not be used to define hypertension since it overestimates BP. The mean of second and third measurement offers the advantage of better reproducibility over single measurements.

Electronic supplementary material

The online version of this article (doi:10.1186/s12872-017-0468-7) contains supplementary material, which is available to authorized users.

Comparative review of the blood pressure-lowering and cardiovascular benefits of telmisartan and perindopril

Hypertension is a major cardiovascular (CV) risk factor, and blood pressure (BP)-lowering treatment substantially reduces the risk. This review compares the available clinical evidence from the BP-lowering and CV-outcome studies of telmisartan and perindopril, which are among the most intensively studied members of their respective classes. The PubMed database was searched for telmisartan and perindopril publications meeting the following criteria: 1) head-to-head comparison trials for BP lowering; and 2) CV-outcome studies (ie, ones with a CV event, mortality, or hospitalization outcome) in patients with CV risk factors but without heart failure. In comparative trials, telmisartan treatment resulted in significantly higher reduction in trough BP and mean ambulatory diastolic BP for the last 8 hours of the dosing interval compared with perindopril. In mainly placebo-controlled CV-outcome studies in patients with hypertension, CV benefits with perindopril were associated with large reductions in BP. There were no CV outcome studies with telmisartan in patients with hypertension. The beyond-BP-lowering CV-protective benefits of telmisartan were demonstrated in the active-controlled ONTARGET (ONgoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial) trial, which included patients with controlled BP at baseline. In general, the trials discussed in this review reinforce the fact that perindopril and telmisartan are two long-acting antihypertensive drugs that reduce BP over 24 hours, and are the best-evidenced drugs in their class with proven CV protection. It is also clear that the benefits are not a “class effect”, and vary between the different drugs within each class. Hence, the best approach for treatments tailored to individual patient needs should be evidence-based specific drugs, rather than a drug-class recommendation for achieving therapeutic targets.

Biological variation of cardiovascular risk factors in patients with diabetes

Biological variation refers to the natural fluctuations found when repeated measurements are made in a biological system. Generally, biological variation remains within narrow boundaries in health, but may differ in pathological states, with implications for the diagnosis and monitoring of disease processes. In disease, biological variation may alter such that any subsequent measurement may need to have a greater difference compared with a healthy control to be biologically relevant. Treatments such as insulin or anti-hypertensive therapy have been shown to reduce biological variability closer to normal levels and theoretically this may help prevent complication development or progression in conditions such as diabetes. This article reviews how biological variation can influence our identification and assessment of vascular risk factors in a person with diabetes. The role of biological variation in the diagnosis of diabetes (glucose and HbA1c) is then examined. Finally, the influence that common treatments in diabetes have in modifying biological variation is described.

Effectiveness of unilateral nephrectomy for renal hypertension in adults

OBJECTIVE

This study investigated the effectiveness of unilateral nephrectomy in the treatment of renal hypertension in adults with an atrophic kidney, and set out to establish whether this is an appropriate mode of treatment for renal hypertension not otherwise controlled by antihypertensive drugs or other surgical procedures.

METHODS

We conducted a retrospective review of 600 consecutive patients who underwent laparoscopic renal surgery from 1998 to 2006 by a single surgeon. Seventeen underwent unilateral nephrectomy for the management of uncontrolled renal hypertension to remove a non-functioning, scarred, and contracted kidney. All patients had normal contralateral kidneys and normal renal functions preoperatively. Results were analysed by Wilcoxon's signed rank test. Statistically significant results (p < 0.0001) with a mean reduction in systolic blood pressure of 27 mmHg and diastolic blood pressure of 17.5 mmHg, more than 6 months after unilateral nephrectomy for treatment of renal hypertension were consistently maintained.

RESULTS

Of the potential modifying factors related to reduction in blood pressure, only age was found to modify the reduction in systolic blood pressure, with a Spearman's rank correlation coefficient of -0.538 (p = 0.026). At 6 months, the mean reduction in systolic blood pressure was 27 mmHg and that for diastolic blood pressure was 17.5 mmHg (p < 0.0001, Wilcoxon's signed rank test).

CONCLUSION

Our data suggest that patients with renal hypertension and unilateral kidney atrophy, treated with laparoscopic nephrectomy, have significant, effective and at least medium term blood pressure control.

The Management of Blood Pressure After Stroke

BACKGROUND

Control of hypertension is a well-established goal of primary prevention of stroke, but management of blood pressure in patients with a previous stroke or in the setting of acute stroke is complicated by the effect blood pressure changes may have on cerebral perfusion.

REVIEW SUMMARY

For patients with previous transient ischemic attack or chronic stroke, blood pressure reduction appears to be a safe and important facet of the secondary prevention of recurrent stroke. Less information is available concerning blood pressure management in acute stroke. Current protocols require strict blood pressure control in patients who are treated with thrombolytic therapy, to reduce the risk of hemorrhagic complications. In patients presenting with acute intracerebral hemorrhage, blood pressure reduction does not appear to cause significant reduction of cerebral blood flow, but at this time there are no studies to determine if there is a clinical benefit of acute blood pressure reduction in these patients. Finally, blood pressure reduction is not routinely recommended in patients with acute ischemic stroke, as it may precipitate further cerebral ischemia. Preliminary studies suggest, in fact, that there may be a role in the future for blood pressure elevation in the treatment of patients with acute ischemic stroke.

CONCLUSIONS

Current data support the use of blood pressure reduction in the secondary prevention of stroke in patients with cerebrovascular disease. In the setting of acute stroke, however, data are limited and blood pressure management must be tailored to the specific clinical situation.

Das Herz bei arterieller Hypertonie

The term hypertensive heart disease covers the entities of left ventricular hypertrophy, microangiopathy and endothelial dysfunction resulting in diastolic and systolic dysfunction, arrhythmias and increased cardiovascular risk. From the pathophysiological point of view, this is caused by the hypertrophy of cardiac myocytes, interstitial fibrosis and media hypertrophy of the arterioles. Microangiopathy can be diagnosed as the earliest sign of hypertensive heart disease, with diastolic dysfunction also being found as an early change. In further persisting arterial hypertension left ventricular hypertrophy develops (often asymmetric) and later a systolic dysfunction. Clinically, the patients suffer from angina pectoris, dyspnea and rhythm disorders. Left ventricular hypertrophy is associated with an increased risk of malignant ventricular arrhythmias. Thus, the main therapeutic principle should be antihypertensive therapy with the goal of regression of hypertrophy leading to decreased mortality risk.

La population âgée hémodialysée : évaluer et prendre en charge le risque de déclin cognitif

Epidemiological data suggest a large prevalence of cognitive impairment in elderly patients on haemodialysis. They are frequently exposed to pathologies that affect the brain, and hold a plurality of risk factors for neurodegenerative and vascular dementia. Cognitive dysfunctions, because of their medical and socio-economical consequences, may led to discuss the indication for haemodialysis and its profit for the elderly patient. These facts highlight the advantage of a regular assessment of cognitive functions in this population. They also suggest the need in the future of a multidisciplinary intervention for these patients, for a better evaluation of interventions aimed on primary and secondary prevention of cognitive decline in the elderly group.

[Alzheimer's disease: cardiovascular risk factors must be assessed]

BACKGROUND

Dementia is nowadays of major importance in public health. Alzheimer's disease and vascular cognitive impairments are its main aetiology in the elderly. The cause of Alzheimer's disease remains unknown. The factor initiating the physiopathology of this neurodegenerative disease is source of controversy.

CURRENT KNOWLEDGE AND KEY POINTS

The theory of a neurotoxicity initiated by amyloid deposition is questioned. A growing number of data suggest a central role of cardiovascular risk factors and alteration of arterial walls, inducing chronic brain hypoperfusion, as the primary trigger in the physiopathology of the disease. These data are based on epidemiological, physiopathological, neuroimaging, neuropathological and pharmacological studies. However, the exact link between arteriosclerosis, vascular cognitive impairment and Alzheimer's disease remains controversial.

FUTURE PROSPECTS AND PROJECTS

These debates point out the crucial importance of the assessment of cardiovascular risk factors, as a preventable cause, either of cognitive decline, morbidity and mortality. In this aim, major targets could be different when primary or secondary prevention are at stake. These controversies also suggest new research directions towards Alzheimer's disease physiopathology, and for pharmacological interventions aimed on the prevention of cognitive decline or the curative treatment for this disease.

Can the Renin-Angiotensin System Protect Against Stroke? A Focus on Angiotensin II Receptor Blockers

From a patient's perspective, stroke is the most devastating form of cardiovascular disease, representing the number one cause of permanent disability in the United States. Treatment of hypertension significantly reduces the risk of stroke; however, it is unclear whether all antihypertensive agents are equivalent in this regard. Angiotensin-converting enzyme (ACE) inhibitors have been shown to reduce the risk of cardiovascular events, including stroke. Although attenuation of the renin-angiotensin system (RAS) is often credited with the blood pressure-independent effects of this class of agents, this hypothesis has not been confirmed with regard to the end point of stroke. In fact, drugs that activate the RAS, such as diuretics and dihydropyridine calcium channel blockers, are as effective or superior to ACE inhibitors for stroke prevention. Angiotensin II receptor blockers (ARBs) selectively block the angiotensin II subtype I receptor, which results in a reflexive increase in levels of angiotensin II and unopposed activation of angiotensin II subtype 2 receptors. Clinical trials comparing ARBs with active controls have reported significant reductions in stroke in ARB-treated patients. Data on ARBs and other drugs that activate the RAS (diuretics and dihydropyridine calcium channel blockers) support a potential role for the RAS in protecting against stroke. Ongoing trials with ARBs are evaluating stroke as a primary end point, and results should help to further elucidate the role of ARBs in this disease. Until then, it is prudent to treat hypertension with an agent or combination of agents that are likely to result in a rapid and sustained reduction in blood pressure, taking into consideration patient characteristics, comorbidities, tolerability, and cost.

Sexual Dysfunction in Male Patients with Hypertension

Evidence suggests that arterial hypertension, in addition to being a cardiovascular and renal risk factor, may also be associated with an impairment of male sexual function. Since other cardiovascular risk factors, especially diabetes mellitus, have also been shown to correlate with impaired sexual function it has been proposed that sexual and especially erectile dysfunction may, at least in part, represent just another manifestation of atherosclerotic vascular disease. In addition to hypertension itself, sexual function in male hypertensive patients may also be affected by antihypertensive drug treatment. Available evidence suggests that centrally acting sympatholytic agents, beta-adrenoceptor antagonists (beta-blockers) and diuretics may have the potential to further impair sexual function. Calcium channel antagonists and ACE inhibitors may be neutral with respect to this endpoint. Preliminary data from several randomised and open studies have suggested that angiotensin II (AT)(1)-receptor antagonists may even be associated with an improvement of sexual function. However, many aspects of the interaction between hypertension, antihypertensive drug treatment and male sexual function remain unclear. Among other factors, the relative contribution of disease labelling both to the higher incidence of sexual dysfunction in hypertensive versus normotensive males and to the negative impact of treatment remains an open question. Furthermore, dose dependence of the observed effects of antihypertensive agents on sexual function, the role of combination therapy and the anticipation of proposed adverse effects of treatment are unresolved issues. Thus, more data from studies of high quality using standardised definitions and procedures are urgently needed to at least partially resolve some of the many open questions.

Blood Pressure Reduction and Cardiovascular Prevention: An Update Including the 2003-2004 Secondary Prevention Trials

In a meta-analysis published in June 2003, we reported that new and old classes of antihypertensive drugs had similar long-term efficacy and safety. Furthermore, we observed that in clinical trials in hypertensive or high-risk patients gradients in systolic blood pressure (SBP) accounted for most differences in outcome. To test whether our previous conclusions would hold, we updated our quantitative overview with new information from clinical trials published before 2005. To compare new and old antihypertensive drugs, we computed pooled odds ratios from stratified 2 x 2 contingency tables. In a meta-regression analysis, we correlated these odds ratios with corresponding between-group differences in SBP. We then contrasted observed odds ratios with those predicted from gradients in SBP. The main finding of our overview was that reduction in SBP largely explained cardiovascular outcomes in the recently published actively controlled trials in hypertensive patients and in placebo-controlled secondary prevention trials. The published results suggested that dihydropyridine calcium-channel blockers might offer a selective benefit in the prevention of stroke and inhibitors of the renin-angiotensin system in the prevention of heart failure. For prevention of myocardial infarction, the published results were more equivocal, because of the benefit of amlodipine over placebo or valsartan in 2 trials, whereas other placebo-controlled trials of calcium-channel blockers or angiotensin converting enzyme inhibitors did not substantiate the expected benefit with regard to cardiac outcomes. In conclusion, the hypothesis that new antihypertensive drugs might influence cardiovascular prognosis over and beyond their antihypertensive effect remains unproven. Our overview emphasizes the need of tight blood pressure control, but does not allow determining to what extent blood pressure must be lowered for optimal cardiovascular prevention.

The PROGRESS trial three years later: time for a balanced report of effectiveness

Has the use of the phrase “perindopril based blood pressure lowering regimen” resulted in an oversimplistic and hence inaccurate interpretation of the results of the PROGRESS trial creeping into the literature and clinical practice?

Current and future concepts in stroke prevention

Stroke is a major cause of morbidity and mortality in an aging population. The current understanding of the pathophysiology of atherosclerotic diseases, the most common cause of stroke, and the evidence for existing therapeutic interventions for the prevention of stroke are presented. Specifically, we review the evidence for antiplatelet agents, anticoagulants, antihypertensive medications, lipid-lowering agents and carotid endarterectomy for stroke prevention.

Seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure

The National High Blood Pressure Education Program presents the complete Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. Like its predecessors, the purpose is to provide an evidence-based approach to the prevention and management of hypertension. The key messages of this report are these: in those older than age 50, systolic blood pressure (BP) of greater than 140 mm Hg is a more important cardiovascular disease (CVD) risk factor than diastolic BP; beginning at 115/75 mm Hg, CVD risk doubles for each increment of 20/10 mm Hg; those who are normotensive at 55 years of age will have a 90% lifetime risk of developing hypertension; prehypertensive individuals (systolic BP 120-139 mm Hg or diastolic BP 80-89 mm Hg) require health-promoting lifestyle modifications to prevent the progressive rise in blood pressure and CVD; for uncomplicated hypertension, thiazide diuretic should be used in drug treatment for most, either alone or combined with drugs from other classes; this report delineates specific high-risk conditions that are compelling indications for the use of other antihypertensive drug classes (angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, beta-blockers, calcium channel blockers); two or more antihypertensive medications will be required to achieve goal BP (<140/90 mm Hg, or <130/80 mm Hg) for patients with diabetes and chronic kidney disease; for patients whose BP is more than 20 mm Hg above the systolic BP goal or more than 10 mm Hg above the diastolic BP goal, initiation of therapy using two agents, one of which usually will be a thiazide diuretic, should be considered; regardless of therapy or care, hypertension will be controlled only if patients are motivated to stay on their treatment plan. Positive experiences, trust in the clinician, and empathy improve patient motivation and satisfaction. This report serves as a guide, and the committee continues to recognize that the responsible physician's judgment remains paramount.

Relationship Between Blood Pressure and Stroke Risk in Patients With Symptomatic Carotid Occlusive Disease

Background and Purpose— Blood pressure lowering in patients with a previous transient ischemic attack (TIA) or stroke reduces the risk of recurrent stroke and coronary vascular events. However, there is uncertainty about the risks and benefits in patients with severe carotid occlusive disease, particularly those with a carotid occlusion or bilateral ≥70% carotid stenosis in whom cerebral perfusion is often impaired and may depend directly on systemic blood pressure. Therefore, we studied the effect of carotid artery disease on the relationship between blood pressure and stroke risk in patients with recent TIA or stroke.

Methods— We compared the relationship between blood pressure (systolic and diastolic blood pressures, pulse pressure) and stroke risk in TIA and stroke patients with documented stenosis of at least 1 carotid artery [European Carotid Surgery Trial (ECST) and North American Symptomatic Carotid Endarterectomy Trial (NASCET)] with that in TIA and stroke patients with a low prevalence of carotid disease [United Kingdom Transient Ischaemic Attack (UK-TIA) Aspirin Trial]. In ECST and NASCET, we also determined the relationship between blood pressure and stroke risk in patients with unilateral carotid occlusion and patients with bilateral ≥70% carotid stenosis.

Results— Stroke risk on medical treatment increased with blood pressure in ECST and NASCET, but the relationships were less steep than in the UK-TIA trial. The relationship between blood pressure and stroke risk was not affected by the presence of a unilateral carotid occlusion but was significantly affected by the presence of bilateral carotid stenosis ≥70% (interaction: systolic blood pressure, P =0.002; diastolic blood pressure, P =0.03; pulse pressure, P =0.003). In this group, the relationship was inverted because of the high stroke risks at lower blood pressures. This interaction was not present after carotid endarterectomy and was not present for the risk of myocardial infarction.

Conclusions— The risk of stroke increases with blood pressure in the great majority of patients with symptomatic carotid artery disease, but the relationship is less steep than in other patients with TIA or stroke. The relationship is unaffected by unilateral carotid occlusion alone but is inverted in patients with bilateral ≥70% carotid stenosis, suggesting that aggressive blood pressure lowering may not be advisable in this group. These patients represent only a few percent of all patients with TIA or stroke but have a high risk of recurrent stroke.

Perindopril pROtection aGainst REcurrent Stroke Study (PROGRESS): interpretation and implementation

OBJECTIVES

To determine the effects of a perindopril-based blood pressure lowering regimen in hypertensive and non-hypertensive patients with a history of stroke or transient ischaemic attack (TIA).

DESIGN AND METHODS

6105 subjects from 172 centres in Asia, Australasia, and Europe were randomised to receive active treatment (n = 3051) or placebo (n = 3054). Active treatment consisted of a flexible regimen based on the angiotensin-converting enzyme inhibitor perindopril (4 mg daily), with the addition of the diuretic indapamide, at the discretion of treating physicians. The primary outcome was total stroke (fatal or non-fatal). Analysis was by intention to treat.

RESULTS

Active treatment reduced blood pressure by 9/4 mmHg over 4 years of follow-up. 307 (10%) individuals assigned active treatment suffered a stroke, compared with 420 (14%) assigned placebo [relative risk reduction 28% (95% confidence interval 17-38), P < 0.0001]. Active treatment also reduced the risks of total major vascular events [26% (16-34)] including non-fatal myocardial infarction [38% (14-55)], severe cognitive decline [19% (4-32)], stroke-related dementia [34% (3-55)] and disability [18% (8-28)]. There were similar reductions in the risk of stroke in hypertensive and non-hypertensive subgroups (P < 0.01). Combination therapy with perindopril plus indapamide lowered blood pressure by 12/5 mmHg and stroke risk by 43%. Single-drug therapy lowered blood pressure by 5/3 mmHg and produced no significant fall in the risk of stroke.

CONCLUSIONS

The blood-pressure lowering regimen used in Perindopril pROtection aGainst REcurrent Stroke Study (PROGRESS) reduced the risks of stroke and other serious events in hypertensive and non-hypertensive subjects with a history of stroke (whatever the subtype) or transient ischaemic attack. Combination therapy with perindopril and indapamide produced larger blood pressure reductions and larger stroke reductions than monotherapy with perindopril alone. Treatment with these two agents should be considered routinely for all patients with a history of previous stroke or TIA, whether hypertensive or normotensive.

Cardiovascular prevention and blood pressure reduction: a quantitative overview updated until 1 March 2003

BACKGROUND

In a meta-analysis published in October 2001, we reported that new and old classes of antihypertensive drugs had similar long-term efficacy and safety. Furthermore, we observed that in clinical trials in hypertensive or high-risk patients gradients in systolic pressure accounted for most differences in outcome.

OBJECTIVE

To test whether our previous conclusions would hold, we updated our quantitative overview with new information from 14 clinical trials presented before 1 March 2003.

METHODS

To compare new and old antihypertensive drugs, we computed pooled odds ratios from stratified 2 x 2 contingency tables. If Zelen's test of heterogeneity was significant, we used a random effects model. In a meta-regression analysis, we correlated odds ratios with corresponding between-group differences in systolic pressure. We then contrasted observed odds ratios with those predicted from gradients in systolic pressure.

MAIN OUTCOMES

Differences in achieved systolic blood pressure and incidence of total and cardiovascular mortality, cardiovascular events, stroke, myocardial infarction and heart failure. NEW VERSUS OLD DRUGS: In 15 trials, 120 574 hypertensive patients were randomized to old drugs (diuretics or beta-blockers) or new agents [calcium-channel blockers, alpha-blockers, angiotensin-converting enzyme (ACE) inhibitors or angiotensin type-1 receptor (AR1) blockers]. Old and new drugs provided similar protection against total and cardiovascular mortality and fatal plus non-fatal myocardial infarction. Calcium-channel blockers, including (-8%, P = 0.07) or excluding verapamil (-10%, P = 0.02), as well as AR1 blockers (-24%, P = 0.0002) resulted in better stroke prevention than did the old drugs, whereas the opposite trend was observed for ACE inhibitors (+10%, P = 0.03). The risk of heart failure was higher (P < 0.0001) on calcium-channel blockers (+33%) and alpha-blockers (+102%) than on conventional therapy involving diuretics. META-REGRESSION: Between-group differences in achieved systolic pressure ranged from 0.1 to 3.2 mmHg in seven actively controlled trials (73 237 patients), and from 2.1 to 22.1 mmHg in seven studies comparing varying intensities of blood pressure lowering (11 128 patients). For these 14 new trials, we predicted outcome from achieved systolic blood pressure using our previously published meta-regression models based on 30 trials with 149 407 patients. In general, predicted and observed odds ratios were similar. Larger reductions in systolic pressure (weighted mean 1.8 mmHg) in two trials accounted for the advantage of AR1 blockers over conventional therapy in the prevention of stroke. Only for cardiovascular mortality in very old patients (P = 0.02) and for cardiovascular events and myocardial infarction in old Australians (P < 0.05), the observed odds ratios deviated from our predictions based on the gradients in systolic blood pressure.

INTERPRETATION

The hypothesis that new antihypertensive drugs, such as calcium-channel blockers, alpha-blockers, ACE inhibitors or AR1 blockers might influence cardiovascular prognosis over and beyond their antihypertensive effects remains unproven. The finding that blood pressure differences largely accounted for cardiovascular outcome emphasizes the desirability of tight blood pressure control. However, the level to which blood pressure must be lowered to achieve maximal benefit remains currently unknown.

Stroke: a vascular pathology with inadequate management

Stroke is a leading cause of death and disability in the world, and the worldwide burden from stroke will increase further during the 21st century. Major advances in the treatment and prevention of stroke have occurred but additional measures are needed. Much of the modern care of stroke mimics the modern treatment of heart disease, in part because of the success of thrombolytic therapy in improving outcomes. Nevertheless, the impact of thrombolytic therapy is limited because of the short therapeutic window. Additional measures are needed to limit the neurological consequences of stroke. Prevention remains a critical component of the management of patients with cerebrovascular disease. Although surgical therapies and antithrombotic medications (antiplatelet agents and anticoagulants) are effective in lessening the likelihood of stroke or recurrent stroke, new strategies are needed to lower the risk further. Measures aimed at stabilizing the vascular endothelium or preventing fracture of atherosclerotic plaques show great promise. Medications including cholesterol-lowering agents and antihypertensive medications, such as the angiotensin-converting enzyme inhibitors, appear effective in stroke prevention. These agents could be combined with antithrombotic agents and surgical interventions to lessen the risk of stroke.

New strategies for prevention of ischemic stroke: the LIFE study

New strategies to lower the risk of stroke among high-risk persons are being developed. Therapies such as cholesterol-lowering medications and newer antihypertensive agents appear to complement traditional antithrombotic drugs and surgical procedures. Of particular interest is the use of the newer angiotensin-converting enzyme (ACE) inhibitors, which appear to have an effect on stabilizing the vascular endothelium. The Losartan Intervention For Endpoint (LIFE) reduction in hypertension study provides additional data to support the use of the ACE inhibitors to lower the risk of stroke among patients with hypertension and vascular diseases.

New horizons for stroke prevention: PROGRESS and HOPE

Inhibitors of angiotensin-converting enzyme (ACE) act by blocking the conversion of angiotensin I to angiotensin II, which is catalysed by this enzyme. ACE inhibitors also prevent the breakdown of bradykinin, a potent vasodepressor agent, and prevent the effects of angiotensin II, which include increase in blood pressure, peripheral vasoconstriction, and stimulation of aldosterone secretion from the adrenal cortex. Physiological and pathological studies have shown that ACE inhibitors have beneficial effects, such as increasing vascular compliance, regression of periarteriolar collagen area, improvement of coronary reserve, and regression of resistance-artery structure and left-ventricular hypertrophy. Information about the role of ACE inhibitors in stroke prevention has been limited. This review explores the epidemiological evidence for hypertension as a risk factor for stroke, a national guideline for blood-pressure control to reduce the incidence of stroke and cardiovascular disease, the findings of two recently published clinical trials on prevention of stroke and cardiovascular disease after administration of ACE inhibitors (PROGRESS and HOPE), and the implications of the findings for redefinition of future management of blood-pressure control for individuals at high risk of stroke and cardiovascular disease. The PROGRESS and HOPE trials have shown that ACE inhibitors have an important role in the prevention of stroke and cardiovascular-disease events.

Cardiovascular protection and blood pressure reduction: a meta-analysis

BACKGROUND

Whether antihypertensive drugs offer cardiovascular protection beyond blood pressure lowering has not been established. We aimed to investigate whether pharmacological properties of antihypertensive drugs or reduction of systolic pressure accounted for cardiovascular outcome in hypertensive or high-risk patients.

METHODS

In a meta-analysis we extracted summary statistics from published reports, and calculated pooled odds ratios for experimental versus reference treatment. We correlated across-trials odd ratios for differences in systolic pressure between groups.

FINDINGS

We analysed nine randomised trials comparing treatments in 62605 hypertensive patients. Compared with old drugs (diuretics and b-blockers), calcium-channel blockers and angiotensin converting-enzyme inhibitors offered similar overall cardiovascular protection, but calcium-channel blockers provided more reduction in the risk of stroke (13.5%, 95% CI 1.3-24.2, p=0.03) and less reduction in the risk of myocardial infarction (19.2%, 3.5-37.3, p=0.01). Heterogeneity was significant between trials because of high risk of cardiovascular events on doxazosin in one trial, and high risk of stroke on captopril in another; but systolic pressure differed between groups in these two trials by 2-3 mm Hg. Similar systolic differences occurred in a trial of diltiazem versus old drugs, and in three trials of converting-enzyme inhibitor against placebo in high-risk patients. Meta-regression across 27 trials (136124 patients) showed that odds ratios could be explained by achieved differences in systolic pressure.

INTERPRETATION

Our findings emphasise that blood pressure control is important. All antihypertensive drugs have similar long-term efficacy and safety. Calcium-channel blockers might be especially effective in stroke prevention. We did not find that converting-enzyme inhibitors or a-blockers affect cardiovascular prognosis beyond their antihypertensive effects.