Effect of aspirin on mortality in women with symptomatic or silent myocardial ischemia. Israeli BIP Study Group

Antiplatelet agents and anticoagulants for hypertension

BACKGROUND

The main complications of elevated systemic blood pressure (BP), coronary heart disease, ischaemic stroke, and peripheral vascular disease, are related to thrombosis rather than haemorrhage. Therefore, it is important to investigate if antithrombotic therapy may be useful in preventing thrombosis-related complications in patients with elevated BP.

OBJECTIVES

To conduct a systematic review of the role of antiplatelet therapy and anticoagulation in patients with elevated BP, including elevations in systolic or diastolic BP alone or together. To assess the effects of antiplatelet agents on total deaths or major thrombotic events or both in these patients versus placebo or other active treatment. To assess the effects of oral anticoagulants on total deaths or major thromboembolic events or both in these patients versus placebo or other active treatment.

SEARCH METHODS

The Cochrane Hypertension Information Specialist searched the following databases for randomised controlled trials (RCTs) up to January 2021: the Cochrane Hypertension Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL; 2020, Issue 12), Ovid MEDLINE (from 1946), and Ovid Embase (from 1974). The World Health Organization International Clinical Trials Registry Platform and the US National Institutes of Health Ongoing Trials Register (ClinicalTrials.gov) were searched for ongoing trials.  SELECTION CRITERIA: RCTs in patients with elevated BP were included if they were ≥ 3 months in duration and compared antithrombotic therapy with control or other active treatment.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data for inclusion criteria, our prespecified outcomes, and sources of bias. They assessed the risks and benefits of antiplatelet agents and anticoagulants by calculating odds ratios (OR), accompanied by the 95% confidence intervals (CI). They assessed risks of bias and applied GRADE criteria.  MAIN RESULTS: Six trials (61,015 patients) met the inclusion criteria and were included in this review. Four trials were primary prevention (41,695 patients; HOT, JPAD, JPPP, and TPT), and two secondary prevention (19,320 patients, CAPRIE and Huynh). Four trials (HOT, JPAD, JPPP, and TPT) were placebo-controlled and two studies (CAPRIE and Huynh) included active comparators. Four studies compared acetylsalicylic acid (ASA) versus placebo and found no evidence of a difference for all-cause mortality (OR 0.97, 95% CI 0.87 to 1.08; 3 studies, 35,794 participants; low-certainty evidence). We found no evidence of a difference for cardiovascular mortality (OR 0.98, 95% CI 0.82 to 1.17; 3 studies, 35,794 participants; low-certainty evidence). ASA reduced the risk of all non-fatal cardiovascular events (OR 0.63, 95% CI 0.45 to 0.87; 1 study (missing data in 3 studies), 2540 participants; low-certainty evidence) and the risk of all cardiovascular events (OR 0.86, 95% CI 0.77 to 0.96; 3 studies, 35,794 participants; low-certainty evidence). ASA increased the risk of major bleeding events (OR 1.77, 95% CI 1.34 to 2.32; 2 studies, 21,330 participants; high-certainty evidence). One study (CAPRIE; ASA versus clopidogrel) included patients diagnosed with hypertension (mean age 62.5 years, 72% males, 95% Caucasians, mean follow-up: 1.91 years). It showed no evidence of a difference for all-cause mortality (OR 1.02, 95% CI 0.91 to 1.15; 1 study, 19,143 participants; high-certainty evidence) and for cardiovascular mortality (OR 1.08, 95% CI 0.94 to 1.26; 1 study, 19,143 participants; high-certainty evidence). ASA probably reduced the risk of non-fatal cardiovascular events (OR 1.10, 95% CI 1.00 to 1.22; 1 study, 19,143 participants; high-certainty evidence) and the risk of all cardiovascular events (OR 1.08, 95% CI 1.00 to 1.17; 1 study, 19,143 participants; high-certainty evidence) when compared to clopidogrel. Clopidogrel increased the risk of major bleeding events when compared to ASA (OR 1.35, 95% CI 1.14 to 1.61; 1 study, 19,143 participants; high-certainty evidence). In one study (Huynh; ASA verus warfarin) patients with unstable angina or non-ST-segment elevation myocardial infarction, with prior coronary artery bypass grafting (CABG) were included (mean age 68 years, 79.8% males, mean follow-up: 1.1 year). There was no evidence of a difference for all-cause mortality (OR 0.98, 95% CI 0.06 to 16.12; 1 study, 91 participants; low-certainty evidence). Cardiovascular mortality, non-fatal cardiovascular events, and all cardiovascular events were not available. There was no evidence of a difference for major bleeding events (OR 0.13, 95% CI 0.01 to 2.60; 1 study, 91 participants; low-certainty evidence).  AUTHORS' CONCLUSIONS: There is no evidence that antiplatelet therapy modifies mortality in patients with elevated BP for primary prevention. ASA reduced the risk of cardiovascular events and increased the risk of major bleeding events.  Antiplatelet therapy with ASA probably reduces the risk of non-fatal and all cardiovascular events when compared to clopidogrel. Clopidogrel increases the risk of major bleeding events compared to ASA in patients with elevated BP for secondary prevention.  There is no evidence that warfarin modifies mortality in patients with elevated BP for secondary prevention.  The benefits and harms of the newer drugs glycoprotein IIb/IIIa inhibitors, clopidogrel, prasugrel, ticagrelor, and non-vitamin K antagonist oral anticoagulants for patients with high BP have not been studied in clinical trials. Further RCTs of antithrombotic therapy including newer agents and complete documentation of all benefits and harms are required in patients with elevated BP.

Antiplatelet agents and anticoagulants for hypertension

BACKGROUND

Elevated systemic blood pressure results in high intravascular pressure but the main complications, coronary heart disease (CHD), ischaemic strokes and peripheral vascular disease (PVD), are related to thrombosis rather than haemorrhage. Some complications related to elevated blood pressure, heart failure or atrial fibrillation, are themselves associated with stroke and thromboembolism. Therefore it is important to investigate if antithrombotic therapy may be useful in preventing thrombosis-related complications in patients with elevated blood pressure.

OBJECTIVES

To conduct a systematic review of the role of antiplatelet therapy and anticoagulation in patients with high blood pressure, including those with elevations in both systolic and diastolic blood pressure, isolated elevations of either systolic or diastolic blood pressure, to address the following hypotheses: (i) antiplatelet agents reduce total deaths and/or major thrombotic events when compared to placebo or other active treatment; and (ii) oral anticoagulants reduce total deaths and/or major thromboembolic events when compared to placebo or other active treatment.

SEARCH METHODS

Electronic databases (MEDLINE, EMBASE, DARE, CENTRAL, Hypertension Group specialised register) were searched up to January 2011. The reference lists of papers resulting from the electronic searches and abstracts from national and international cardiovascular meetings were hand-searched to identify missed or unpublished studies. Relevant authors of studies were contacted to obtain further data.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in patients with elevated blood pressure were included if they were of at least 3 months in duration and compared antithrombotic therapy with control or other active treatment.

DATA COLLECTION AND ANALYSIS

Data were independently collected and verified by two reviewers. Data from different trials were pooled where appropriate.

MAIN RESULTS

Four trials with a combined total of 44,012 patients met the inclusion criteria and are included in this review. Acetylsalicylic acid (ASA) did not reduce stroke or 'all cardiovascular events' compared to placebo in primary prevention patients with elevated blood pressure and no prior cardiovascular disease. In one large trial ASA taken for 5 years reduced myocardial infarction (ARR 0.5%, NNT 200), increased major haemorrhage (ARI 0.7%, NNT 154), and did not reduce all cause mortality or cardiovascular mortality. In one trial there was no significant difference between ASA and clopidogrel for the composite endpoint of stroke, myocardial infarction or vascular death. In two small trials warfarin alone or in combination with ASA did not reduce stroke or coronary events. The ATC meta-analysis of antiplatelet therapy for secondary prevention in patients with elevated blood pressure reported an absolute reduction in vascular events of 4.1% as compared to placebo. Data on the 10,600 patients with elevated blood pressure from the 29 individual trials included in the ATC meta-analysis was requested but could not be obtained.

AUTHORS' CONCLUSIONS

Antiplatelet therapy with ASA for primary prevention in patients with elevated blood pressure provides a benefit, reduction in myocardial infarction, which is negated by a harm of similar magnitude, increase in major haemorrhage.The benefit of antiplatelet therapy for secondary prevention in patients with elevated blood pressure is many times greater than the harm.Benefit has not been demonstrated for warfarin therapy alone or in combination with aspirin in patients with elevated blood pressure. Ticlopidine, clopidogrel and newer antiplatelet agents such as prasugrel and ticagrelor have not been sufficiently evaluated in patients with high blood pressure. Newer antithrombotic oral drugs such as dabigatran, rivaroxaban, apixaban and endosaban are yet to be tested in patients with high blood pressure.Further trials of antithrombotic therapy including with newer agents and complete documentation of all benefits and harms are required in patients with elevated blood pressure.

Aspirin use, dose, and clinical outcomes in postmenopausal women with stable cardiovascular disease: the Women's Health Initiative Observational Study

BACKGROUND

Despite compelling evidence that aspirin reduces fatal and nonfatal vascular events among the overall population in various settings, women have frequently been underrepresented and their data underreported. We sought to evaluate the relationship between aspirin use, dose (81 or 325 mg), and clinical outcomes among postmenopausal women with stable cardiovascular disease (CVD).

METHODS AND RESULTS

Women with CVD (n=8928) enrolled in the Women's Health Initiative Observational Study were used for this analysis. The primary outcome was the incidence of all-cause mortality and cardiovascular events (myocardial infarction, stroke, and cardiovascular death). Among 8928 women with stable CVD, 4101 (46%) reported taking aspirin, of whom 30% were on 81 mg and 70% were on 325 mg. At 6.5 years of follow-up, no significant association was noted for aspirin use and all-cause mortality or cardiovascular events. However, after multivariate adjustment, aspirin use was associated with a significantly lower all-cause (adjusted hazard ratio, 0.86 [0.75 to 0.99]; P=0.04) and cardiovascular-related mortality (adjusted hazard ratio, 0.75 [0.60 to 0.95]; P=0.01) compared with no aspirin. Aspirin use was associated with a lower risk of cardiovascular events (adjusted hazard ratio, 0.90 [0.78 to 1.04]; P=0.14), which did not meet statistical significance. Compared with 325 mg, use of 81 mg was not significantly different for all-cause mortality, cardiovascular events, or any individual end point.

CONCLUSIONS

After multivariate adjustment, aspirin use was associated with significantly lower risk of all-cause mortality, specifically, cardiovascular mortality, among postmenopausal women with stable CVD. No significant difference was noted between 81 mg and 325 mg of aspirin. Overall, aspirin use was low in this cohort of women with stable CVD.

Antithrombotic therapy in hypertension: a Cochrane Systematic review

Although elevated systemic blood pressure (BP) results in high intravascular pressure, the main complications of hypertension are related to thrombosis rather than haemorrhage. It therefore seemed plausible that use of antithrombotic therapy may be useful in preventing thrombosis-related complications of elevated BP. The objectives were to conduct a systematic review of the role of antiplatelet therapy and anticoagulation in patients with BP, to address the following hypotheses: (i) antiplatelet agents reduce total deaths and/or major thrombotic events when compared to placebo or other active treatment; and (ii) oral anticoagulants reduce total deaths and/or major thromboembolic events when compared to placebo or other active treatment. A systematic review of randomised studies in patients with elevated BP was performed. Studies were included if they were >3 months in duration and compared antithrombotic therapy with control or other active treatment. One meta-analysis of antiplatelet therapy for secondary prevention in patients with elevated BP reported an absolute reduction in vascular events of 4.1% as compared to placebo. Acetylsalicylic acid (ASA) did not reduce stroke or 'all cardiovascular events' compared to placebo in primary prevention patients with elevated BP and no prior cardiovascular disease. Based on one large trial, ASA taken for 5 years reduced myocardial infarction (ARR, 0.5%, NNT 200 for 5 years), increased major haemorrhage (ARI, 0.7%, NNT 154), and did not reduce all cause mortality or cardiovascular mortality. In two small trials, warfarin alone or in combination with ASA did not reduce stroke or coronary events. Glycoprotein IIb/IIIa inhibitors as well as ticlopidine and clopidogrel have not been sufficiently evaluated in patients with elevated BP. To conclude for primary prevention in patients with elevated BP, antiplatelet therapy with ASA cannot be recommended since the magnitude of benefit, a reduction in myocardial infarction, is negated by a harm of similar magnitude, an increase in major haemorrhage. For secondary prevention in patients with elevated BP, antiplatelet therapy is recommended because the magnitude of the absolute benefit is many times greater. Warfarin therapy alone or in combination with aspirin in patients with elevated BP cannot be recommended because of lack of demonstrated benefit. Further trials of antithrombotic therapy are required in patients with elevated BP.

Silent myocardial ischemia: concepts and controversies

Silent myocardial ischemia is a relatively common, but poorly understood, clinical entity. The most accurate means of detecting silent myocardial ischemia and the precise treatment endpoints remain unclear. However, the amount of ischemic myocardium appears to correlate with the likelihood of future adverse cardiac events. Evidence suggests that patients at highest risk of severe myocardial ischemia, even in the absence of symptoms, derive the greatest benefit from an aggressive diagnostic and therapeutic approach. This paper reviews the diagnosis and treatment of silent myocardial ischemia, and its clinical implication in select patient groups: those without coronary artery disease, those with coronary artery disease, diabetic patients, postrevascularization patients, and women.

Antiplatelet agents and anticoagulants for hypertension

BACKGROUND

Although elevated systemic blood pressure results in high intravascular pressure, the main complications, coronary heart disease (CHD), ischaemic strokes and peripheral vascular disease (PVD), are related to thrombosis rather than haemorrhage. Some complications related to elevated blood pressure, heart failure or atrial fibrillation, are themselves associated with stroke and thromboembolism. It therefore seemed plausible that use of antithrombotic therapy may be particularly useful in preventing thrombosis-related complications of elevated blood pressure.

OBJECTIVES

To conduct a systematic review of the role of antiplatelet therapy and anticoagulation in patients with blood pressure, including those with elevations in both systolic and diastolic blood pressure, isolated elevations of either systolic or diastolic blood pressure, to address the following hypotheses: (i) antiplatelet agents reduce total deaths and/or major thrombotic events when compared to placebo or other active treatment; and (ii) oral anticoagulants reduce total deaths and/or major thromboembolic events when compared to placebo or other active treatment.

SEARCH STRATEGY

Reference lists of papers resulting from this search, electronic database searching (MEDLINE, EMBASE, DARE), and abstracts from national and international cardiovascular meetings were studied to identify unpublished studies. Relevant authors of these studies were contacted to obtain further data.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in patients with elevated blood pressure were included if they were of at least 3 months in duration and compared antithrombotic therapy with control or other active treatment.

DATA COLLECTION AND ANALYSIS

Data were independently collected and verified by two reviewers. Data from different trials were pooled where appropriate.

MAIN RESULTS

The ATC meta-analysis of antiplatelet therapy for secondary prevention in patients with elevated blood pressure reported an absolute reduction in vascular events of 4.1% as compared to placebo. Data on the patients with elevated blood pressure from the 29 individual trials included in this meta-analysis was requested but could not be obtained. Three additional trials met the inclusion criteria and are reported on here. Acetylsalicylic acid (ASA) did not reduce stroke or 'all cardiovascular events' compared to placebo in primary prevention patients with elevated blood pressure and no prior cardiovascular disease. Based on one large trial (HOT trial), ASA taken for 5 years reduced myocardial infarction (ARR, 0.5%, NNT 200 for 5 years), increased major haemorrhage (ARI, 0.7%, NNT 154), and did not reduce all cause mortality or cardiovascular mortality. There was no significant difference between ASA and clopidogrel for the composite endpoint of stroke, myocardial infarction or vascular death in one trial (CAPRIE 1996). In two small trials warfarin alone or in combination with ASA did not reduce stroke or coronary events.

REVIEWERS' CONCLUSIONS

For primary prevention in patients with elevated blood pressure, anti-platelet therapy with ASA cannot be recommended since the magnitude of benefit, a reduction in myocardial infarction, is negated by a harm of similar magnitude, an increase in major haemorrhage. For secondary prevention in patients with elevated blood pressure (ATC meta-analysis: APTC 1994) antiplatelet therapy is recommended because the magnitude of the absolute benefit is many times greater. Warfarin therapy alone or in combination with aspirin in patients with elevated blood pressure cannot be recommended because of lack of demonstrated benefit. Glycoprotein IIb/IIIa inhibitors as well as ticlopidine and clopidogrel have not been sufficiently evaluated in patients with elevated blood pressure. Further trials of antithrombotic therapy with complete documentation of all benefits and harms are required in patients with elevated blood pressure.

Thrombolysis and antithrombotic therapy for coronary artery disease

Aspirin in a dose of 160 to 325 mg should be administered on day 1 of an acute MI and continued indefinitely on a daily basis. Thrombolytic therapy should be administered within 6 to 12 hours after the onset of an acute MI with ST segment elevation or with left bundle branch block. Primary coronary angioplasty when available should be used rather than thrombolytic therapy in the treatment of older persons with acute MI who are poor candidates for thrombolytic therapy. Intravenous heparin should be given in persons with acute MI undergoing primary coronary angioplasty or surgical coronary revascularization and in persons with acute MI at high risk for systemic embolization. Long-term oral warfarin should be given after MI for the secondary prevention of MI in post-MI persons unable to tolerate daily aspirin, in post-MI persons with persistent atrial fibrillation, and in post-MI persons with left ventricular thrombus. Platelet GP IIb/IIIa inhibitors should be administered along with aspirin and enoxaparin in the acute phase of management of persons with unstable angina pectoris or non-Q wave MI. Aspirin should be administered daily indefinitely to persons after MI, to persons with unstable angina pectoris, to persons with stable angina pectoris, and to persons undergoing coronary revascularization. Aspirin plus ticlopidine or aspirin plus clopidogrel should be used in persons undergoing coronary artery stenting. Platelet GP IIb/IIIa inhibitors should be used at the time of coronary angioplasty, coronary atherectomy, or coronary stenting. Aspirin, 160 to 325 mg daily, is recommended in older men and postmenopausal women who are at high risk for developing coronary events in addition to treating their coronary risk factors.

Treatment of acute myocardial infarction and 30-day mortality among women and men

BACKGROUND

Previous studies have suggested that women with acute myocardial infarction receive less aggressive therapy than men. We used data from the Cooperative Cardiovascular Project to determine whether women and men who were ideal candidates for therapy after acute myocardial infarction were treated differently.

METHODS

Information was abstracted from the charts of 138,956 Medicare beneficiaries (49 percent of them women) who had an acute myocardial infarction in 1994 or 1995. Multivariate analysis was used to assess differences between women and men in the medications administered, the procedures used, the assignment of do-not-resuscitate status, and 30-day mortality.

RESULTS

Among ideal candidates for therapy, women in all age groups were less likely to undergo diagnostic catheterization than men. The difference was especially pronounced among older women; for a woman 85 years of age or older, the adjusted relative risk was 0.75 (95 percent confidence interval, 0.68 to 0.83). Women were somewhat less likely than men to receive thrombolytic therapy within 60 minutes (adjusted relative risk, 0.93; 95 percent confidence interval, 0.90 to 0.96) or to receive aspirin within 24 hours after arrival at the hospital (adjusted relative risk, 0.96; 95 percent confidence interval, 0.95 to 0.97), but they were equally likely to receive beta-blockers (adjusted relative risk, 0.99; 95 percent confidence interval, 0.95 to 1.03) and somewhat more likely to receive angiotensin-converting-enzyme inhibitors (adjusted relative risk, 1.05; 95 percent confidence interval, 1.02 to 1.08). Women were more likely than men to have a do-not-resuscitate order in their records (adjusted relative risk, 1.26; 95 percent confidence interval, 1.22 to 1.29). After adjustment, women and men had similar 30-day mortality rates (hazard ratio, 1.02; 95 percent confidence interval, 0.99 to 1.04).

CONCLUSIONS

As compared with men, women receive somewhat less aggressive treatment during the early management of acute myocardial infarction. However, many of these differences are small, and there is no apparent effect on early mortality.

Effects of aspirin treatment on survival in non-insulin-dependent diabetic patients with coronary artery disease. Israeli Bezafibrate Infarction Prevention Study Group

PURPOSE

The benefit of aspirin treatment among diabetic patients with chronic coronary artery disease is not well established. The purpose of this study was to assess the effect of aspirin on cardiac and total mortality in a large cohort of diabetic patients with established coronary artery disease and to compare it with the effect of aspirin in nondiabetic counterparts.

PATIENTS AND METHODS

In this observational study among patients screened for participation in the Bezafibrate Infarction Prevention Study, the effects of aspirin treatment in 2,368 non-insulin-dependent diabetic patients with coronary artery disease were compared to those in 8,586 nondiabetic patients. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated with proportional hazards models.

RESULTS

Fifty-two percent of diabetic patients and 56% of nondiabetic patients reported aspirin therapy. After 5.1 +/- 1.3 (mean +/- SD) years of follow-up, the absolute benefit per 100 patients treated with aspirin was greater in diabetic patients than in nondiabetic patients (cardiac mortality benefit: 5.0 versus 2.1, and all-cause mortality benefit: 7.8 versus 4.1). Overall cardiac mortality among diabetic patients treated with aspirin was 10.9% versus 15.9% in the nonaspirin group (P < 0.001), and all-cause mortality was 18.4% and 26.2% (P < 0.001). After adjustment for possible confounders, treatment with aspirin was an independent predictor of reduced overall cardiac (HR = 0.8; 95% CI: 0.6-1.0) and all-cause mortality (HR = 0.8; 95% CI: 0.7-0.9) among diabetic patients, similar to those in nondiabetic patients.

CONCLUSION

Treatment with aspirin was associated with a significant reduction in cardiac and total mortality among non-insulin-dependent diabetic patients with coronary artery disease. The absolute benefit of aspirin was greater in diabetic patients than in those without diabetes.