Antiplatelet and anticoagulant therapy in the secondary prevention of ischemic heart disease

Ticagrelor versus aspirin 2 years after coronary bypass: Observational analysis from the TARGET trial

BACKGROUND

Compared to conventional aspirin therapy, ticagrelor did not improve vein graft patency 1 year after coronary bypass surgery (CABG) in the ticagrelor antiplatelet therapy to reduce graft events and thrombosis (TARGET) trial. However, it is unknown whether ticagrelor may impact graft patency long-term following surgery.

METHODS

In the TARGET multicenter trial, 250 CABG patients were randomized to aspirin 81 mg or ticagrelor 90 mg twice daily. In this observational analysis, 2 years after surgery, vein graft occlusion and clinical events were compared among subjects who agreed to a second year of double-blind study drug administration (N = 156).

RESULTS

Two-year graft assessment was performed for 142 patients (80 aspirin patients, 62 ticagrelor patients, 425 total grafts), with an overall 2-year graft occlusion rate of 10.6%. Vein graft occlusion at 2 years, the primary outcome of this study, did not significantly differ between the two groups (15.7% vs. 13.2%, aspirin vs. ticagrelor, p = .71). The incidence of vein grafts with any disease (stenosis or occlusion) did not significantly differ between the groups (19.4% vs. 19.8%, aspirin vs. ticagrelor, p = 1.00), and the number of patients with vein graft disease did not significantly differ between the groups (30.0% vs. 29.0%, aspirin vs. ticagrelor, p = 1.00). Vein grafts developing new disease did not significantly differ between the two groups (1.5% vs. 3.8%, aspirin vs. ticagrelor, p = .41). Freedom from major adverse cardiovascular events at 2 years was similar between the groups (p = .75).

CONCLUSION

Compared to conventional aspirin therapy, ticagrelor did not significantly reduce vein graft disease 2 years after CABG.

Ticagrelor versus aspirin and vein graft patency after coronary bypass: A randomized trial

BACKGROUND

Antiplatelet therapy prevents saphenous vein graft (SVG) occlusion and improves outcomes after coronary artery bypass graft surgery (CABG). However, the optimal postoperative antiplatelet regimen remains unclear. The goal of the Ticagrelor Antiplatelet Therapy to Reduce Graft Events and Thrombosis (TARGET) trial was to assess whether early postoperative ticagrelor reduces SVG occlusion compared to conventional aspirin therapy.

METHODS

In this multi-center double-blind randomized trial, 250 patients who had CABG with SVG were randomized to receive either aspirin 81 mg twice daily or ticagrelor 90 mg twice daily. The primary outcome was SVG occlusion at 1 year.

RESULTS

Altogether, 123 patients were randomized to aspirin and 127 received ticagrelor. One-year graft assessment was performed in 202 patients (80.8%), examining 588 grafts, yielding an overall graft occlusion rate of 10.9%. The primary outcome, SVG occlusion at 1 year, did not significantly differ between the two groups (17.4% vs. 13.2%, aspirin vs. ticagrelor, p = .30). The incidence of vein grafts with any disease (stenosis or occlusion) did not significantly differ between the groups (21.5% vs. 22.3%, aspirin vs. ticagrelor, p = .90), and the number of patients with vein graft disease did not significantly differ between the groups (29.4% vs. 28.0%, aspirin vs. ticagrelor, p = .88). Freedom from major adverse cardiovascular events at 1 year was similar between the groups (p = .60).

CONCLUSIONS

Compared to conventional aspirin therapy, ticagrelor did not significantly reduce vein graft occlusion 1 year after CABG. Further study will assess the impact of ticagrelor on 2-year graft patency for this cohort.

Evaluation of the activated partial thromboplastin time and its influential factors in ischemic heart disease patients under heparin treatment

This study aimed to detect the defects of the current methods used to monitor unfractionated heparin (UFH) anticoagulant effect and find possible assistive parameters for activated partial thromboplastin time (aPTT) test to improve treatment performance. The required information was gathered from patients' case records, treatment charts and laboratory reports. Kendall's tau correlation coefficient was calculated for analysing the relationship between variables. The partial least squares (PLS) and the stepwise multiple regression were operated, and the area under the receiver operating characteristic curve (AUC) and the r-squared (r2) were used to show the analytical ability of the models, respectively. Overall, 102 UFH-receiving ischemic heart disease patients participated in this study. The aPTT value varied from 30 to 95 s (mean ± SD = 44 ± 14). Therapeutic aPTT values were observed in 15% of hospitalization days. The aPTT value showed statistically significant correlations with mean UFH infusion (U/kg/h), age, prothrombin time (PT), smoking, international normalized ratio, haemoglobin (Hgb) and blood triglyceride level. Triglyceride level and PT were efficacious predictors of aPTT value (P < 0.001, r2 = 0.336). Moreover, blood urea nitrogen (BUN) and blood creatinine (Cr) levels were the best predictors for mortality. The mean BUN/Cr ratio was 18 ± 5 and 25 ± 12 in nonexpired and expired subjects, respectively. If calibrated institution-specific therapeutic aPTT ranges and updated weight-based UFH nomograms get employed, aPTT test, along with the BUN/Cr ratio and Hgb level, as assistive parameters for predicting haemorrhagic incidents, would be near ideal monitoring method in UFH-receiving patients.

Impact of ticagrelor versus aspirin on graft patency after CABG: Rationale and design of the TARGET (ticagrelor antiplatelet therapy to reduce graft events and thrombosis) randomized controlled trial (NCT02053909)

RATIONALE

Saphenous vein graft disease remains a major limitation of coronary artery bypass graft surgery (CABG). Up to 20% of vein grafts will occlude within the first year after CABG despite standard aspirin antiplatelet therapy. However, more potent postoperative platelet inhibition with ticagrelor may improve graft patency. The goal of this study will be to evaluate the efficacy of ticagrelor, as compared to aspirin, for the prevention of saphenous vein graft occlusion following CABG.

STUDY DESIGN

The Ticagrelor Antiplatelet Therapy to Reduce Graft Events and Thrombosis (TARGET) study is a multi-center double-blind randomized controlled trial enrolling patients who have undergone multi-vessel CABG with at least one saphenous vein graft. Patients are being randomized to receive either aspirin 81 mg twice per day or ticagrelor 90 mg twice per day for 2 years starting within 7 days after surgery. The projected enrollment is 150 patients in each arm (300 total patients). Patients will undergo computed tomography (CT) coronary angiography at 1 and 2 years after surgery to assess the incidence of vein graft occlusion and stenosis.

CONCLUSION

To our knowledge, this trial is the first prospective study to evaluate the impact of early postoperative ticagrelor on 1- and 2-year graft patency after CABG. Furthermore, it is also the first trial to use a novel antiplatelet agent as a standalone, without aspirin, after CABG. Should ticagrelor reduce the incidence of postoperative graft occlusion, the results of this study will redefine modern antiplatelet management following coronary bypass surgery (ClinicalTrials.govNCT02053909).

Clopidogrel treatment during pregnancy: a case report and a review of literature

Management of ischemic heart disease in pregnant women is still difficult, as there is little experience with many of the newer treatments such as clopidogrel. The safety of clopidogrel in pregnancy is unknown, especially in combination with aspirin. Its use during gestation has been described in a few case reports. We describe the case of a 36-year-old woman in her 9th week of pregnancy with a history of chronic hypertension, dyslipidemia and CAD, who required antiplatelet treatment. Clopidogrel and aspirin were administrated until one week before delivery and a healthy child was born at 36 weeks of pregnancy by caesarean section, without any complication.

Assessment of atherothrombosis and its treatment in Mexico: first-year data of the REACH Registry

BACKGROUND

Atherothrombosis, a generalized and progressive process, is currently a major healthcare problem in Mexico.

METHODS

The worldwide Reduction of Atherothrombosis for Continued Health (REACH) registry aimed to evaluate risk factors for atherosclerosis, long-term cardiovascular (CV) event rates, and current management of either patients with established symptomatic atherosclerotic disease or asymptomatic subjects with multiple risk factors for atherothrombotic disease. One-year follow-up of the global REACH database was available for 64 977 outpatients. This report includes the Mexican subregistry wherein 62 internists, cardiologists, and neurologists evaluated baseline patient characteristics, risk factors, medications, and CV event rates as primary outcomes at 1-year follow-up.

RESULTS

Complete 1-year follow-up data were available for 837 Mexicans. We observed a high prevalence of diabetes (47.1%), hypertension (74.7%), and hypercholesterolemia (57.8%). Antiplatelet, antihypertensive and/or glucose-lowering agents, and lipid-lowering drugs were used in 87.6%, 84.1%, and 61% of patients, respectively. The all-cause mortality rate was 3.3%. The composite outcome CV death/myocardial infarction/stroke/hospitalization for atherothrombotic events was higher in the symptomatic group (14.6%) than in asymptomatic subjects with multiple risk factors (5.1%; P = 0.01), similar to Latin American results of the global REACH report. The highest CV event rate occurred among symptomatic atherothrombotic patients with 3 vascular disease locations (30.2%), followed by those with 2 (21.9%) and 1 location (13.4%; P = 0.0006).

CONCLUSIONS

Prevalence of risk factors and CV event rates including hospitalization in Mexican atherothrombotic patients was high despite the current medication use, which suggests it is necessary to have more aggressive risk-factor management.

Gas-phase fragmentation study of a novel series of synthetic 2-oxo-2H-benzopyrano[2,3-d]pyrimidine derivatives using electrospray ionization tandem mass spectroscopy measured with a quadrupole orthogonal time-of-flight hybrid instrument

The fragmentation patterns of a series of six novel synthesized benzopyranopyrimidine derivatives 1-6, possessing the same 2-oxo-2H-benzopyrano[2,3-d]pyrimidine backbone structure, were investigated by electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (MS/MS) techniques using a quadrupole orthogonal time-of-flight (QqToF)-hybrid instrument. The series of six pure benzopyranopyrimidine compounds contained three constitutional isobaric isomers (compounds 4-6). A simple methodology, based on the use of ESI (positive ion mode) and increasing the declustering potential in the atmospheric pressure/vacuum interface resulting in collision-induced dissociation (CID), was used to enhance the formation of the product ions. In general, the novel synthetic benzopyranopyrimidine derivatives 1-6 afforded exact accurate masses for the protonated molecules. This led to the confirmation of both molecular masses and chemical structures of the studied compounds. The breakdown routes of the protonated molecules were rationalized by conducting low-energy CID-MS/MS analyses. It was shown that the MS/MS fragmentation routes for the protonated molecules 1 and 2 were similar, and that the MS/MS fragmentations of the constitutional isobaric protonated molecules 5 and 6 were identical. It was also shown that the gas-phase CID fragmentations of 5 and 6 were different from that of their constitutional isomer 4. Finally, the ESI-MS and CID-MS/MS analyses of the protonated molecules that were obtained from the monodeuterated benzopyranopyrimidine derivatives 1-6 confirmed the values obtained for the exact masses, the precise structural assignments of all product ions and all the pathways described in the proposed CID fragmentations.

C-reactive protein levels increase after exercise testing in patients with increased platelet reactivity

Aspirin has the potential to influence C-reactive protein (CRP) levels, an inflammatory marker, by its anti-inflammatory activity. Persistently increased platelet reactivity, however, can be detected with different laboratory methods despite aspirin therapy in some patients. The aim of this study was to investigate the effects of increased platelet reactivity on CRP levels at rest and after exercise in patients with documented or suspected coronary artery disease. Blood samples were collected from 100 patients (age, 58.1+/-8.5 years; 63.0% men) who were treated with 100 or 300 mg/day enteric-coated aspirin for at least 7 days, before and immediately after treadmill test for CRP analyses. Platelet reactivity was measured by the standardized platelet function analyzer-100, and increased platelet reactivity was defined as a normal collagen/epinephrine closure time (<165 s). Of the 100 patients, 82 had normal platelet reactivity (group A) and 18 had increased platelet reactivity (group B). The CRP levels increase was statistically significant after exercise in patients with increased platelet reactivity [group A: 2.3 (1.4-4.3) to 2.8 (1.6-4.9) mg/l, P=0.09; group B: 3.3 (2.0-4.5) to 4.7 (2.9-8.5) mg/l, P=0.02]. Detecting increased platelet reactivity is associated with an increase in CRP levels. The clinical significance of this finding needs to be further investigated.

Assessment of biochemical aspirin resistance at rest and immediately after exercise testing

Some aspirin-treated patients experience thromboembolic events, a phenomenon termed 'aspirin resistance', which may be clinical or biochemical by definition. Physical exercise is known to enhance platelet secretion and aggregability. To evaluate the presence of biochemical aspirin resistance at rest and immediately after exercise in individuals with stable coronary artery disease or coronary artery disease risk factors. We prospectively enrolled 101 patients who had received 100 or 300 mg/day enteric-coated aspirin for at least 7 days. Biochemical aspirin resistance (defined as normal collagen-epinephrine closure time < 165 s) was studied using the standardized platelet function analyzer. Of the 101 patients, 63 were aspirin sensitive both at rest and immediately after exercise, 18 exhibited biochemical aspirin resistance both at rest and after exercise, and 20 were aspirin sensitive at rest but exhibited biochemical aspirin resistance immediately after exercise. The results of exercise testing were similar in all three groups (each P > 0.05). Our results indicate that in almost 20% of the patients, aspirin did not seem to protect against exercise-induced platelet activation, despite the presence of aspirin sensitivity at rest. We did not, however, determine the extent to which the biochemical aspirin resistance noted in our study applied to clinical events.

Lack of effect of enteric coating on aspirin-induced inhibition of platelet aggregation in healthy volunteers

BACKGROUND

Aspirin inhibits platelet aggregation and is widely used in the treatment of cardiovascular disease. Some individuals are less responsive to aspirin's antiplatelet effect, a phenomenon termed aspirin resistance. It is not known whether the antiplatelet effect is fully preserved with the enteric-coated (EC) formulation.

METHODS

We performed a prospective randomized trial of 50 healthy volunteers using a crossover design to compare the EC with the standard aspirin formulations. The subjects received a 7-day course of each aspirin formulation (81-mg) (Bayer Corporation, Morristown, NJ) separated by a 3-week washout period. Platelet function was measured before and after each course using optical aggregometry (with arachidonic acid and adenosine diphosphate as agonists) and a point-of-care platelet assay.

RESULTS

The assays were reproducible, and the variation in baseline platelet function was small to moderate between the subjects. There was no difference in the extent of platelet inhibition between the EC and standard formulations with any of the 3 assays. With the point-of-care platelet assay, the mean aspirin effect favoring the standard formulation (more aggregation inhibition) compared with the EC formulation was 1.6% +/- 15.8% (P = .60 for difference between the formulations). The corresponding optical aggregometry values were -3.4% +/- 39.5% (P = .97) and -1.4% +/- 16.6% (P = .75) for arachidonic acid and adenosine diphosphate, respectively.

CONCLUSIONS

Compared with standard aspirin, EC aspirin appears to exhibit similar inhibition of platelet aggregation in healthy volunteers. Furthermore, point-of-care platelet assessment correlated well with the gold standard of laboratory-based optical platelet aggregometry.

Synthesis, antiplatelet and antithrombotic activities of new 2-substituted benzopyrano[4,3-d]pyrimidin-4-cycloamines and 4-amino/cycloamino-benzopyrano[4,3-d]pyrimidin-5-ones

Atherothrombotic coronary artery disease, associated with deep vein thrombosis, is one of the most common causes of death worldwide. Recently, antiplatelet combination therapy using agents with different mechanisms of action, such as aspirin, dipyridamole, and thienopyridines, seems to be an attractive preventive approach. Moreover, several large, randomized clinical trials support combination therapy with aspirin plus warfarin in high-risk patients with atherosclerotic heart disease. Our research on the benzopyrano[4,3-d]pyrimidine system gave rise to the synthesis of a large number of compounds endowed with in vitro anti-aggregating activity. Several SAR considerations suggest that the benzopyranopyrimidine system is an appropriate scaffold to obtain molecules that are able to act simultaneously in different pathways of aggregation. Now, we report the synthesis of new 2-substituted benzopyrano[4,3-d]pyrimidin-4-cycloamines and 4-amino/cycloamino-benzopyrano[4,3-d]pyrimidin-5-ones and the results of the pharmacological study on haemostasis. Some tested compounds showed a large-spectrum antiplatelet activity in vitro, and are more potent than aspirin as antithrombotics in vivo but, at variance with aspirin, they do not increase bleeding. This paper describes novel antithrombotic compounds with an interesting pharmacological profile and a potentially attractive benefit/risk ratio, with their mechanism of action generally, but not exclusively, dependent on antiplatelet activity, deserving further investigations.

Aspirin and clopidogrel resistance: an emerging clinical entity

Antiplatelet therapy is a cornerstone of cardiovascular medicine. Aspirin and clopidogrel have emerged as critical therapies in the treatment of cardiovascular disease. Despite their efficacy, patients on these medications continue to suffer complications. Millions of patients are currently on low-dose antiplatelet therapy but it is unknown how many of these patients are under-treated or on the wrong medication. Aspirin and clopidogrel resistance are emerging clinical entities with potentially severe consequences such as recurrent myocardial infarction, stroke, or death. The mechanism of resistance remains incompletely defined, but there are specific clinical, cellular, and genetic factors that influence therapeutic failure. These factors range from physicians who fail to prescribe these medications despite appropriate indications to polymorphisms of platelet membrane glycoproteins. Rapid and accurate diagnosis of antiplatelet resistance also remains an issue as new bedside tests are developed. By understanding the mechanism of therapeutic failure and by improving the diagnosis of this clinical entity, a new era of individualized antiplatelet therapy may arise with routine measurements of platelet activity in the same way that cholesterol, blood pressure, and blood sugar are followed, thus improving the care for millions of people.

The clopidogrel after surgery for coronary artery disease (CASCADE) randomized controlled trial: clopidogrel and aspirin versus aspirin alone after coronary bypass surgery [NCT00228423]

Background

Saphenous vein graft disease remains a major limitation of coronary artery bypass graft surgery. The process of saphenous vein intimal hyperplasia begins just days after surgical revascularization, setting the stage for graft atherosclerotic disease and its sequalae. Clopidogrel improves outcomes in patients with atherosclerotic disease, and is effective at reducing intimal hyperplasia in animal models of thrombosis. Therefore, the goal of this study will be to evaluate the efficacy of clopidogrel and aspirin therapy versus aspirin alone in the prevention of saphenous vein graft intimal hyperplasia following coronary artery bypass surgery.

Methods

Patients undergoing multi-vessel coronary artery bypass grafting and in whom at least two saphenous vein grafts will be used are eligible for the study. Patients will be randomized to receive daily clopidogrel 75 mg or placebo, in addition to daily aspirin 162 mg, for a one year duration starting on the day of surgery (as soon as postoperative bleeding has been excluded). At the end of one year, all patients will undergo coronary angiography and intravascular ultrasound assessment of one saphenous vein graft as selected by randomization. The trial will be powered to test the hypothesis that clopidogrel and aspirin will reduce vein graft intimal hyperplasia by 20% compared to aspirin alone at one year following bypass surgery.

Discussion

This trial is the first prospective human study that will address the question of whether clopidogrel therapy improves outcomes and reduces saphenous vein graft intimal hyperplasia following cardiac surgery. Should the combination of clopidogrel and aspirin reduce the process of vein graft intimal hyperplasia, the results of this study will help redefine modern antiplatelet management of coronary artery bypass patients.

Evaluation of serum levels of solubilized adhesion molecules in patients with aortocoronary saphenous vein grafts

OBJECTIVE

To assess the diagnostic importance of serum-solubilized adhesion molecules, vascular cell adhesion molecule-1, intercellular adhesion molecule-1, sE-selectin and sP-selectin in aortocoronary saphenous vein graft disease.

METHODS

The study population was composed of two groups consisting of 41 patients with saphenous vein graft stenosis (stenosis group) and 43 patients without saphenous vein graft stenosis (no-stenosis group) based on the results of coronary angiography. All patients underwent coronary artery bypass graft operation involving the use of at least one saphenous vein graft for bypass. At the time of cardiac catheterization, it had been more than 1 year since the operation.

RESULTS

Serum level of sP-selectin was significantly higher in the stenosis group than in the no-stenosis group (72.9+/-21.7 versus 48.7+/-18.6 ng/ml, P<0.001). No differences were found between the two groups with respect to serum levels of sE-selectin, intercellular adhesion molecule-1 and vascular cell adhesion molecule-1. Multivariate analysis revealed that only serum levels of sP-selectin, high-density lipoprotein cholesterol and low-density lipoprotein cholesterol were independently correlated with the stenosis of saphenous vein grafts. A cutoff value of serum sP-selectin >57.5 ng/ml yields a specificity of 79.5%, a sensitivity of 73.3% and a positive predictive value of 80.5% for saphenous vein graft stenosis.

CONCLUSION

In this study, sP-selectin level was found to be significantly higher in the group that had late aortocoronary saphenous vein bypass graft disease. This result suggests that platelet activation may play a causal role in late graft disease.

Clopidogrel added to aspirin versus aspirin alone in secondary prevention and high-risk primary prevention: rationale and design of the Clopidogrel for High Atherothrombotic Risk and Ischemic Stabilization, Management, and Avoidance (CHARISMA) trial

BACKGROUND

Clopidogrel is a more potent antiplatelet agent than aspirin, resulting in greater clinical efficacy in patients with atherothrombotic disease. Furthermore, the combination of clopidogrel plus aspirin has been demonstrated to be superior to aspirin alone in the treatment of patients with acute coronary syndromes and after coronary stenting. Whether dual antiplatelet therapy is superior to aspirin monotherapy for high-risk primary prevention and secondary prevention is unknown.

METHODS AND RESULTS

The Clopidogrel for High Atherothrombotic Risk and Ischemic Stabilization, Management, and Avoidance (CHARISMA) study was designed to evaluate the efficacy and safety of clopidogrel plus aspirin versus placebo plus aspirin in patients with established coronary, cerebral, or peripheral arterial disease or in patients with multiple risk factors for atherothrombosis who have not yet sustained an ischemic event. This randomized, international, multicenter, double-blinded, placebo-controlled study has finished enrolling patients worldwide. A total of 15,603 patients will be followed long term. The primary end point will be the composite of vascular death, myocardial infarction, or stroke. Rates of severe bleeding will also be compared between the two arms of the study.

CONCLUSIONS

This large-scale trial of patients at high risk for atherothrombotic events will allow determination of the value of a strategy of adding clopidogrel to the current standard of care, including low-dose aspirin, for a wide spectrum of patients with atherothrombosis.

Scientific and therapeutic advances in antiplatelet therapy

Over the past decade, the platelet has emerged as a pivotal entity in cardiovascular diseases. Indeed, the 'preeminence of the platelet' has spawned a variety of drugs that have been shown in large-scale randomized trials to improve patient outcomes in acute coronary syndromes and percutaneous revascularization procedures. Although the platelet was initially viewed only as a bystander in haemostasis, it is now evident that the platelet is in fact a key mediator of thrombosis as well as of inflammation. New insights at the cellular and genomic levels will probably generate novel drugs to inhibit platelet function more effectively and safely than previously possible.

Elevated expression of integrin alpha(IIb) beta(IIIa) in drug-naïve, first-episode schizophrenic patients

BACKGROUND

Patients with schizophrenia have an increased risk over the general public of developing cardiovascular illness. It is unknown if there are functional changes in platelet surface receptors in schizophrenia. We therefore analyzed the surface expression of glycoprotein (GP)Ib, the integrin receptor alpha(IIb)beta(IIIa), CD62 (P-selectin), and CD63, and investigated platelet function in schizophrenic patients compared with healthy volunteers.

METHODS

Nineteen drug-naive, first-episode patients with a DSM IV diagnosis of paranoid schizophrenia were compared with matched healthy controls. Flow cytometry was used to assess platelet surface expression levels of GPIb, alpha(IIb)beta(IIIa), CD62, and CD63. Adenosine diphosphate-induced platelet aggregation was assayed.

RESULTS

The schizophrenic patients had a significantly (p < .0001) increased number of 68,145 +/- 8,260.1 alpha(IIb)beta(IIIa) receptors, platelet compared with 56,235 +/- 8,079.4 receptors, platelet in healthy controls.

CONCLUSIONS

Patients with schizophrenia have increased platelet expression of alpha(IIb)beta(IIIa), which may contribute to their increased risk of cardiovascular illness compared with the general population.

Superiority of clopidogrel versus aspirin in patients with prior cardiac surgery

BACKGROUND

After coronary artery bypass surgery, patients have a high cumulative rate of graft closure and recurrent ischemic events. We sought to determine whether antiplatelet therapy with clopidogrel would be more effective than aspirin, the accepted standard, in these patients.

METHODS AND RESULTS

The event rates for all-cause mortality, vascular death, myocardial infarction, stroke, and rehospitalization were determined for the 1480 patients with a history of cardiac surgery randomized to either clopidogrel or aspirin in a trial of 19 185 patients. The event rate per year of vascular death, myocardial infarction, stroke, or rehospitalization was 22.3% in the 705 patients randomized to aspirin and 15.9% in the 775 patients randomized to clopidogrel (P:=0.001). A risk reduction was also seen in each of the individual end points examined, including a 42.8% relative risk reduction in vascular death in patients on clopidogrel versus aspirin (P:=0.030). In a multivariate model incorporating baseline clinical characteristics, clopidogrel therapy was independently associated with a decrease in vascular death, myocardial infarction, stroke, or rehospitalization in patients with a history of cardiac surgery, with a 31.2% relative risk reduction (95% CI, 15.8 to 43.8; P:=0.0003). Although clopidogrel therapy was efficacious in the entire Clopidogrel Versus Aspirin in Patients at Risk of Ischemic Events (CAPRIE) population, multivariate analysis demonstrated that patients with previous cardiac surgery derived particular benefit (P:=0.015).

CONCLUSION

Compared with aspirin, clopidogrel therapy results in a striking reduction in the elevated risk for recurrent ischemic events seen in patients with a history of prior cardiac surgery, along with a decreased risk of bleeding.