The purpose of this multicentre cohort study was to examine the relationship between antiplatelet therapy (APT) at the time of coronary artery bypass grafting (CABG) and postoperative bleeding complications, transfusion requirements and adverse cardiovascular events.
A matched-pair analysis was carried out on 6350 consecutive patients undergoing CABG at the three university hospitals in Western Denmark. Patients exposed to aspirin or clopidogrel within 5 days before surgery were compared with those not exposed to these drugs. The data used in the study were retrieved from the Western Denmark Heart Registry.
Of the 6350 patients enrolled, 1846 (29%) had been exposed to aspirin or clopidogrel within 5 days prior to CABG (the APT group). Matching with the remaining 4504 (71%) patients of the control group resulted in 1132 pairs of patients. Patients in the APT group had greater mean chest tube drainage volumes (946 vs 775 ml; P 1000 ml (odds ratio [OR]: 1.07, 95% confidence interval [CI]: 0.55-1.34). Preoperative clopidogrel use, on the other hand, was associated with greater reoperation rates (10.2 vs 3.9% in the control group; P = 0.005) and was an independent predictor of severe postoperative bleeding (OR: 2.08, 95% CI: 1.55-2.80). Overall, preoperative APT had no significant effect on postoperative 30-day mortality, incidence of myocardial infarction, stroke or need for dialysis.
Preoperative APT is associated with increased bleeding and greater transfusion requirements after CABG. Clopidogrel exposure is associated with greater reoperation rates and is an independent risk factor for severe postoperative bleeding.
Dual antiplatelet therapy, with aspirin and a thienopyridine, is the accepted treatment after percutaneous coronary intervention (PCI). No clear evidence exists regarding the ideal dosage of aspirin. Recent guidelines recommend higher-dose aspirin because of the possible decrease in stent thrombosis. The purpose of this study was to test the hypothesis that high-dose aspirin of 325 mg decreases death and myocardial infarction (MI) compared to a lower dose of 81 mg in patients undergoing PCI.
An observational cohort study of 1,840 consecutive patients who underwent PCI was conducted. Patients who did not survive to discharge were excluded. The primary endpoint was a composite of all-cause mortality and MI at 1 year.
Nine-hundred and thirty patients (50.5%) were discharged on 325 mg of aspirin and 910 (49.5%) were discharged of 81 mg. The risk of all-cause mortality or MI was not significantly different between patients: low-dose 5.49% (50/910) vs. high-dose 4.19% (39/930); adjusted odds ratio [OR], 1.16; 95% confidence interval [CI], 0.73-1.85). In a multivariable analysis, the Charlson comorbidity score (OR, 1.37; 95% CI, 1.18-1.58) and urgent PCI (OR, 1.75; 95% CI, 1.03-3.00) were associated with increased death or MI. Among patients with drug-eluting stents, the use of low-dose aspirin did not predispose them to death or MI (adjusted OR, 1.12, 95% CI, 0.53-2.34).
In this large contemporary analysis of PCI patients, no differences in death or MI were observed at 1 year between patients discharged on low-dose aspirin 81 mg compared to patients on a higher dose.
The stroke rate in atrial fibrillation is 4.5% per year, with death or permanent disability in over half. The risk of stroke varies from under 1% to over 20% per year, related to the risk factors of congestive heart failure, hypertension, age, diabetes, and prior stroke or transient ischemic attack (TIA). Major bleeding with vitamin K antagonists varies from about 1% to over 12% per year and is related to a number of risk factors. The CHADS(2) index and the HAS-BLED score are useful schemata for the prediction of stroke and bleeding risks. Vitamin K antagonists reduce the risk of stroke by 64%, aspirin reduces it by 19%, and vitamin K antagonists reduce the risk of stroke by 39% when directly compared with aspirin. Dabigatran is superior to warfarin for stroke prevention and causes no increase in major bleeding. We recommend that all patients with atrial fibrillation or atrial flutter, whether paroxysmal, persistent, or permanent, should be stratified for the risk of stroke and for the risk of bleeding and that most should receive antithrombotic therapy. We make detailed recommendations as to the preferred agents in various types of patients and for the management of antithrombotic therapies in the common clinical settings of cardioversion, concomitant coronary artery disease, surgical or diagnostic procedures with a risk of major bleeding, and the occurrence of stroke or major bleeding. Alternatives to antithrombotic therapies are briefly discussed.
Clopidogrel therapy increases bleeding risk, but whether it influences short-term mortality after peptic ulcer bleeding (PUB) is unknown. The objective was to examine whether clopidogrel use at the time of PUB increases 30-day mortality. We conducted this cohort study in northern Denmark (population 1.7 million). We used the Danish National Patient Registry, covering all hospitals, to identify all patients with a first-ever inpatient diagnosis of endoscopically or surgically confirmed PUB between 1998 and 2008 and their comorbidities. From the prescription database in the region, we ascertained the use of clopidogrel at the time of admission (current use) or before admission (former use) and use of concurrent medications. We obtained mortality data from the Danish Civil Registration System. We used regression modeling to compute mortality rate ratios (MRRs) with 95% confidence intervals (CIs), controlling for potential confounders. We identified 6951 patients with bleeding peptic ulcers. At admission, 122 (1.8%) were current users of clopidogrel, 143 (2.1%) were former users, and 6686 (96.2%) were nonusers. Thirty-day mortality was 5.7% for current users, 7.0% for former users, and 8.0% for nonusers. The adjusted 30-day MRR was reduced in both current and former users, compared with nonusers (MRR = 0.72, 95% CI 0.34, 1.52 and MRR = 0.71, 95% CI 0.38, 1.32, respectively). There was no notable modification of the association within gender or age strata. Although the use of clopidogrel increases the risk of PUB, former use and current use of clopidogrel were not associated with increased short-term mortality after admission for this condition.
• The CYP3A4 inhibition by lipophilic statins may attenuate the effectiveness of clopidogrel. • No studies have measured drug exposure in a time-varying manner that detects discontinuation and restart of clopidogrel and statin therapy, allowing clinical quantification of the interaction effect.
• Clopidogrel and CYP3A4-metabolizing statin use were each associated with a substantially reduced rate of major adverse cardiovascular events within 12 months after coronary stent implantation. • Although we observed an interaction between use of clopidogrel and statins, statin use vs. non-use was not associated with an increased rate of major adverse cardiovascular events in patients using clopidogrel after coronary stent implantation.
To examine whether CYP3A4-metabolizing statin use modified the association between clopidogrel use and major adverse cardiovascular events (MACE) after coronary stent implantation, using time-varying drug exposure ascertainment.
We conducted this population-based cohort study in Western Denmark (population: 3 million) using medical databases. We identified all 13 001 patients with coronary stent implantation between 2002 and 2005 and their comorbidities. During 12 months of follow-up, we tracked the use of clopidogrel and CYP3A4-metabolizing statins and the rate of MACE. We used Cox regression to compute hazard ratios (HRs) controlling for potential confounders.
The rate of MACE per 1000 person years was 104 for concomitant clopidogrel and statin use, 130 for clopidogrel without statin use, 108 for statin without clopidogrel use and 446 for no use of either drug. The adjusted HR comparing clopidogrel use with non-use was 0.68 (95% confidence interval (CI) 0.58, 0.79) among statin users and 0.34 (95% CI 0.29, 0.40) among statin non-users, yielding an interaction effect (i.e. relative rate increase) of 1.97 (95% CI 1.59, 2.44). The adjusted HR for MACE comparing statin use with non-use was 0.97 (95% CI 0.83, 1.13) among clopidogrel users and 0.49 (95% CI 0.42, 0.57) among clopidogrel non-users.
Clopidogrel and CYP3A4-metabolizing statin use were each associated with a substantially reduced rate of MACE within 12 months after coronary stent implantation. Although we observed an interaction between use of clopidogrel and statins, statin use vs. non-use was not associated with an increased rate of MACE in patients using clopidogrel after coronary stent implantation.
Platelet function testing could be useful when assessing the risk for bleeding during treatment with antiplatelet drugs. This has been indicated in several studies, including the Antiplatelet Therapy for Reduction of Myocardial Damage During Angioplasty-Bleeding (ARMYDA-BLEEDS) study, which demonstrated that testing with a point-of-care assay correlated with bleeding events after percutaneous coronary intervention. To standardize bleeding definitions, the Bleeding Academic Research Consortium (BARC) published a consensus report, which is in need of data-driven validation. Hence, the investigators conducted an observational, prospective, single-center study of 474 patients receiving clopidogrel and aspirin who underwent coronary angiography with or without percutaneous coronary intervention from October 2006 to May 2011. Platelet reactivity was measured with adenosine diphosphate-induced single-platelet function testing (Plateletworks) at the start of coronary angiography. The primary end point was the 30-day incidence of bleeding as defined by BARC and ARMYDA-BLEEDS. The aim of the present study was to investigate the relation between on-treatment platelet reactivity and the 30-day incidence of bleeding complications according to the BARC and ARMYDA-BLEEDS definitions. Patients in the first platelet aggregation quartile had a higher frequency of type 2 or higher BARC bleeding and ARMYDA-BLEEDS-defined bleeding
The effects on plasma, red cell and platelet fatty acids of taking 12 g/day of ethyl-eicosapentaenoate for 16 months: dihomogammalinolenic, arachidonic and docosahexaenoic acids and relevance to Inuit metabolism.
A patient with mantle cell lymphoma took 12g/day of ethyl-eicosapentaenoate for 16 months. Compared to reference values, eicosapentaenoic and docosapentaenoic acids were elevated in plasma, red cells and platelets but docosahexaenoic acid levels were in the normal range. Arachidonic acid levels were moderately reduced but dihomogammalinolenic acid levels remained in the normal range. In spite of a long chain n-3 fatty acid intake higher than in most Inuit populations, arachidonic acid levels remained considerably higher in this patient than in the Inuit. The implications for understanding of fatty acid metabolism in humans are discussed.
The objective of this study was to examine the clinical efficacy of clopidogrel treatment on death and recurrent myocardial infarction (MI) among MI patients revascularized by coronary artery bypass graft surgery (CABG).
The benefit from post-operative clopidogrel in CABG-treated MI patients is largely unknown.
All patients admitted with first-time MI between 2002 and 2006, treated with CABG within 180 days after admission, were identified by nationwide administrative registers. Clopidogrel treatment was determined by claimed prescriptions after discharge from surgery. Risk of death or recurrent MI, and of a combined end point of the 2, were assessed by cumulative incidence and Cox proportional hazards model. A propensity score-matched subgroup analysis was done.
We included 3,545 patients, and of these, 957 (27.0%) were treated with clopidogrel after CABG. Mean follow-up was 466 ± 144 days. Among patients treated with clopidogrel, 39 (4.1%) died or experienced a recurrent MI, whereas that occurred in 203 (7.8%) patients without clopidogrel (log-rank p = 0.0003). Hazard ratio was 0.59 (95% confidence interval [CI]: 0.42 to 0.85) for patients treated with clopidogrel, with no-clopidogrel as reference. By propensity score, of 945 patients with or without clopidogrel treatment who were matched, death or recurrent MI occurred in 38 (4.0%) patients with clopidogrel and 57 (6.0%) without clopidogrel (log-rank p = 0.05). Corresponding hazard ratio was 0.67 (95% CI: 0.44 to 1.00) for clopidogrel users, with no-clopidogrel as reference.
Among MI patients revascularized by CABG, only 27% received clopidogrel after discharge. Clopidogrel-treated patients had a lower risk of the combined end point of death or recurrent MI. Focus on discharge clopidogrel treatment of these patients should be made.
Comment In: J Am Coll Cardiol. 2011 Aug 30;58(10):1085; author reply 1085-621867852
Comment In: J Am Coll Cardiol. 2011 Aug 30;58(10):1084-5; author reply 1085-621867851