Clopidogrel plus aspirin versus aspirin alone for preventing cardiovascular disease

Antiplatelet Therapy in Acute Mild-Moderate Ischemic Stroke (ATAMIS): a parallel, randomised, open-label, multicentre, prospective study

Background

A recent study shows that dual antiplatelet therapy with clopidogrel plus aspirin is superior to aspirin monotherapy for minor stroke, which is defined as a National Institutes of Health Stroke Scale (NIHSS)score of ≤3. However, acute mild-moderate ischaemic stroke (4≤NIHSS≤10) still needs aggressive antiplatelet intervention to prevent deterioration and recurrence of stroke. The efficacy and safety of dual antiplatelet therapy versus aspirin monotherapy in the population are not clear. A multicentre clinical trial is designed to evaluate the efficacy and safety of clopidogrel plus aspirin therapy versus aspirin monotherapy within 48 hours of symptom onset of mild-moderate ischaemic stroke.

Methods/Design

The study is a randomised, open-label, multicentre, prospective trial with a target enrolment of 2700 patients from 60 centres in Northeast China. A treatment allocation identification number to each enrolled patient will be provided by a random number generator. The follow-up time for the clopidogrel plus aspirin and aspirin monotherapy groups is 90 days. The primary efficacy endpoint is a stroke progression event, which is defined as ≥4 point increase in the NIHSS score in 48 hours. The second efficacy endpoints include new ischaemic stroke within 90 days, change in the NIHSS score within 14 days, modified Rankin Scale score on day 90 and other vascular or death events within 90 days. The safety endpoints include mucocutaneous haemorrhage, organ haemorrhage and intracranial haemorrhage, adverse events and severe adverse events. χ² test, t-test (or Mann-Whitney test), survival analysis and Cox proportional hazards models will be conducted. The findings of the study may provide an important evidence for clinical practice for these patients.

Discussion

The trial will be conducted under a rational design and will provide valuable evidence on the appropriate treatment for this population.

Ethics and dissemination

The study was reviewed and approved by the Ethics Committee of the General Hospital of Shen-Yang Military Region (no K(2016) 6).

Trial registration number

NCT02869009; Pre-results.

Management standards for stable coronary artery disease in India

Coronary artery disease (CAD) is one of the important causes of cardiovascular morbidity and mortality globally, giving rise to more than 7 million deaths annually. An increasing burden of CAD in India is a major cause of concern with angina being the leading manifestation. Stable coronary artery disease (SCAD) is characterised by episodes of transient central chest pain (angina pectoris), often triggered by exercise, emotion or other forms of stress, generally triggered by a reversible mismatch between myocardial oxygen demand and supply resulting in myocardial ischemia or hypoxia. A stabilised, frequently asymptomatic phase following an acute coronary syndrome (ACS) is also classified as SCAD. This definition of SCAD also encompasses vasospastic and microvascular angina under the common umbrella.

Systematic reviews and meta-analyses for more profitable strategies in peripheral artery disease

In the peripheral arteries, a thrombus superimposed on atherosclerosis contributes to the progression of peripheral artery disease (PAD), producing intermittent claudication (IC), ischemic necrosis, and, potentially, loss of the limb. PAD with IC is often undiagnosed and, in turn, undertreated. The low percentage of diagnosis (∼30%) in this setting of PAD is of particular concern because of the potential worsening of PAD (amputation) and the high risk of adverse vascular outcomes (vascular death, coronary artery disease, stroke). A Medline literature search of the highest-quality systematic reviews and meta-analyses of randomized controlled trials documents that, due to risk of bias, imprecision, and indirectness, the overall quality of the evidence concerning diagnostic tools and antithrombotic interventions in PAD is generally low. Areas of research emerge from the information collected. Appropriate treatments for PAD patients will only derive from ad-hoc studies. Innovative imaging techniques are needed to identify PAD subjects at the highest vascular risk. Whether IC unresponsive to physical exercise and smoking cessation identifies those with a heritable predisposition to more severe vascular events deserves to be addressed. Devising ways to improve prevention of vascular events in patients with PAD implies a co-ordinated approach in vascular medicine.

No effect of clopidogrel activity or cessation on vascular function or markers of inflammation

The platelet adenosine diphosphate (ADP)-receptor blocker clopidogrel is effective in reducing the rate of thrombosis in cardiovascular disease, but may also have nonplatelet activity. However, there is variability in the suppression of platelet function in individuals, leading to the concept of clopidogrel resistance, that is, reduced platelet-suppressing activity. We tested the hypothesis that some of the beneficial effect of clopidogrel may be due to the variable activity of this drug on the vascular system (assessed by plasma markers von Willebrand factor and soluble E-selectin, and functional arterial pulse wave velocity) and inflammation (C-reactive protein and interleukin-6) while 32 patients with coronary artery disease taking 75 mg clopidogrel daily, and again 2 weeks after cessation of clopidogrel therapy. Platelet responsiveness to clopidogrel was assessed by the phosphorylation of intracellular regulatory protein-vasodilator-stimulated phosphoprotein method and aggregometry to ADP. Response to aspirin was assessed using arachidonic acid (AA), and soluble P-selectin and PAC-1 were also measured. While on clopidogrel, there were no relationships between any vascular or inflammatory index and the response to clopidogrel. After stopping clopidogrel, there were no differences in platelet aggregation to AA, or the expression of P-selectin or PAC-1 at rest, or after stimulation by AA, but platelet responses to ADP all increased (p < 0.01). Although soluble P-selectin increased when clopidogrel was stopped (p = 0.006), there were no changes in plasma markers or vascular function. We conclude that 75 mg/day clopidogrel has no effect of markers of vascular function or inflammation.

Primary and secondary prevention of cardiovascular disease: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

This guideline focuses on long-term administration of antithrombotic drugs designed for primary and secondary prevention of cardiovascular disease, including two new antiplatelet therapies.

METHODS

The methods of this guideline follow those described in Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines in this supplement.

RESULTS

We present 23 recommendations for pertinent clinical questions. For primary prevention of cardiovascular disease, we suggest low-dose aspirin (75-100 mg/d) in patients aged > 50 years over no aspirin therapy (Grade 2B). For patients with established coronary artery disease, defined as patients 1-year post-acute coronary syndrome, with prior revascularization, coronary stenoses > 50% by coronary angiogram, and/or evidence for cardiac ischemia on diagnostic testing, we recommend long-term low-dose aspirin or clopidogrel (75 mg/d) (Grade 1A). For patients with acute coronary syndromes who undergo percutaneous coronary intervention (PCI) with stent placement, we recommend for the first year dual antiplatelet therapy with low-dose aspirin in combination with ticagrelor 90 mg bid, clopidogrel 75 mg/d, or prasugrel 10 mg/d over single antiplatelet therapy (Grade 1B). For patients undergoing elective PCI with stent placement, we recommend aspirin (75-325 mg/d) and clopidogrel for a minimum duration of 1 month (bare-metal stents) or 3 to 6 months (drug-eluting stents) (Grade 1A). We suggest continuing low-dose aspirin plus clopidogrel for 12 months for all stents (Grade 2C). Thereafter, we recommend single antiplatelet therapy over continuation of dual antiplatelet therapy (Grade 1B).

CONCLUSIONS

Recommendations continue to favor single antiplatelet therapy for patients with established coronary artery disease. For patients with acute coronary syndromes or undergoing elective PCI with stent placement, dual antiplatelet therapy for up to 1 year is warranted.

Antithrombotic therapy in peripheral artery disease: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

This guideline focuses on antithrombotic drug therapies for primary and secondary prevention of cardiovascular disease as well as for the relief of lower-extremity symptoms and critical ischemia in persons with peripheral arterial disease (PAD).

METHODS

The methods of this guideline follow those described in Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines in this supplement.

RESULTS

The most important of our 20 recommendations are as follows. In patients aged ≥ 50 years with asymptomatic PAD or asymptomatic carotid stenosis, we suggest aspirin (75-100 mg/d) over no therapy (Grade 2B) for the primary prevention of cardiovascular events. For secondary prevention of cardiovascular disease in patients with symptomatic PAD (including patients before and after peripheral arterial bypass surgery or percutaneous transluminal angioplasty), we recommend long-term aspirin (75-100 mg/d) or clopidogrel (75 mg/d) (Grade 1A). We recommend against the use of warfarin plus aspirin in patients with symptomatic PAD (Grade 1B). For patients undergoing peripheral artery percutaneous transluminal angioplasty with stenting, we suggest single rather than dual antiplatelet therapy (Grade 2C). For patients with refractory claudication despite exercise therapy and smoking cessation, we suggest addition of cilostazol (100 mg bid) to aspirin (75-100 mg/d) or clopidogrel (75 mg/d) (Grade 2C). In patients with critical limb ischemia and rest pain unable to undergo revascularization, we suggest the use of prostanoids (Grade 2C). In patients with acute limb ischemia due to acute thrombosis or embolism, we recommend surgery over peripheral arterial thrombolysis (Grade 1B).

CONCLUSIONS

Recommendations continue to favor single antiplatelet therapy for primary and secondary prevention of cardiovascular events in most patients with asymptomatic PAD, symptomatic PAD, and asymptomatic carotid stenosis. Additional therapies for relief of limb symptoms should be considered only after exercise therapy, smoking cessation, and evaluation for peripheral artery revascularization.

Hypercoagulability in patients undergoing coronary artery bypass grafting: prevalence, patient characteristics and postoperative outcome

OBJECTIVES

To investigate the prevalence of preoperative hypercoagulability assessed by thromboelastography (TEG), to identify patient characteristics associated with hypercoagulability and to explore whether hypercoagulability is associated with a greater risk for myocardial infarction (MI), stroke and mortality 30 days after coronary artery bypass grafting (CABG) surgery.

METHODS

This is a prospective, observational study of 200 consecutive CABG surgery patients. Hypercoagulability was defined as TEG maximum amplitude >69 mm.

RESULTS

Eighty-seven out of 200 (43.5%) CABG patients were TEG-hypercoagulable. In univariate regression analysis, age, female gender, hypertension, severe chronic obstructive pulmonary disease, platelet count and fibrinogen level were significantly associated with TEG-hypercoagulability. Multivariate regression analysis revealed higher age, platelet count and fibrinogen levels as variables independently associated with TEG-hypercoagulability. Thirty-day outcome data: MI (TEG-hypercoagulable 6.9% vs. TEG-normocoagulable 3.7%, NS), stroke (8.0 vs. 2.8%, NS) and mortality (4.6 vs. 0.9%, NS). There was a significant difference in 30-day combined event rate of MI, stroke and mortality (17.2 vs. 6.6%, P = 0.019). In univariate analysis, only female gender and TEG-hypercoagulability were significantly associated with 30-day combined event rate. In multivariate analysis, only female gender was significantly associated with 30-day outcome (P = 0.014), whereas TEG-hypercoagulability demonstrated a trend (P = 0.065).

CONCLUSIONS

Hypercoagulability identified by TEG was preoperatively found in 43.5% of CABG patients, and the findings of this study support the notion that TEG-hypercoagulable patients have a higher risk for a combination of thromboembolic complications and death after surgery.

Antiplatelet agents

The introduction of aspirin as an anti-thrombotic agent some 50 years ago has changed the therapeutic approach in cardiovascular medicine. Since platelets play a key role in the development of arterial thrombosis, antiplatelet drugs serve as a cornerstone in the prevention and the treatment of these conditions. After many years of a "monopoly" of aspirin, ADP receptor P2Y12 inhibitors were introduced with a significant improvement in clinical outcome. Nowadays dual antiplatelet therapy is the common practice for both acute events and secondary prevention in selected groups of patients. Another revolution was the development of potent inhibitors of the platelet integrin GPIIbIIIa, which significantly improved the outcome of percutaneous interventions (PCI), in cardiology. The improved efficacy of multiple-drug therapy is associated with an increased risk of bleeding, which raises the issue of the dosing of these drugs. Recently, numerous studies have reported a variable laboratory response to aspirin and clopidogrel, which correlates with clinical outcome. Several mechanisms have been proposed to cause this variable response, including genetic variability, disease burden and others. A major obstacle in this field is the lack of a standardized method for testing these responses, and thus some studies cannot be compared to others. Ongoing studies are currently investigating the potential translation of these observations into clinical practice. Such studies may lead to a change in the paradigm of antiplatelet therapy, where individual dose adjustment may improve efficacy and safety. Finally, a variety of new drugs are currently in different stages of development, including new P2Y12 receptor inhibitors, thromboxane receptor blockers, direct thrombin inhibitors and other signaling pathway inhibitors including oral GPIIbIIIa inhibitors. Thus, antiplatelet therapy is currently under intensive development toward multiple-drug therapy and personal-dose adjustment, which may improve clinical outcome.

Use of antiplatelet agents for prevention of ischemic stroke

Overall management to lower risk for ischemic stroke is multifaceted. Management includes measures to treat risk factors for accelerated atherosclerosis and stroke, antithrombotic therapies to lower the risk for thromboembolism, and surgery to treat a defined arterial or cardiac lesion. Treatment decisions are made on a case-by-case basis, with most patients receiving some combination of medication and recommendations for lifestyle modification. Some patients will also undergo surgical or endovascular interventions. This article discusses antithrombotic treatment for ischemic stroke prevention, placing major emphasis on the indications for and administration of antiplatelet therapy.