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What's new in Hemostasis: December 2008

FDA Seizes Contaminated Heparin from a Cincinnati Manufacturer

As part of the U.S. Food and Drug Administration's ongoing efforts to ensure that heparin for patients remains safe, the government today seized 11 lots of heparin from Celsus Laboratories Inc. in Cincinnati, Ohio. The five lots of Heparin Sodium Active Pharmaceutical Ingredient (API) and six lots of Heparin Lithium were seized at the FDA's request by U.S. Marshals. These products, which were manufactured from material imported from China, had been found by the agency to be contaminated with over-sulfated chondroitin sulfate (OSCS), a substance that mimics heparin's anticoagulant activity.
OSCS contaminant in injectable drug products containing heparin has been linked to multiple adverse events and deaths initially reported to the FDA in January 2008. Since then, the FDA has put in place a comprehensive inspection and import controls program and has acted to remove from the market heparin materials and products contaminated with OSCS. The seized Celsus heparin - which had entered the United States before the establishment of import controls for the drug - was tested for the presence of OSCS as part of this FDA effort.
To date, the agency has initiated 13 recalls of multiple contaminated medical products containing heparin from several companies.

AHA 2008: Tailoring Clopidogrel Loading on the Basis of Responsiveness Testing Reduces Stent Thrombosis
http://www.medscape.com/viewarticle/583332
Shelley Wood A strategy of measuring platelet responsiveness and tailoring clopidogrel as needed can reduce the rate of early stent thrombosis in patients undergoing PCI, new research shows. The results support a strategy of stratifying patients into one of three groups--good responders, low responders, or "resistants"--whose clopidogrel dose could be tailored as needed.
Others, however, point out that cardiologists have not yet agreed what test is the best in terms of measuring how well patients are responding to antiplatelet therapy or on the best strategy for acting on any information gleaned.
Paganelli et al screened 1122 patients undergoing nonemergent PCI for clopidogrel responsiveness, after they'd received their 600-mg loading dose (plus 250-mg aspirin). Responsiveness was defined by a vasodilator-associated stimulated phosphoprotein (VASP) index of 50% or greater, based on a test that measures the extent to which clopidogrel binds, in vivo, to the P2Y12 platelet-surface chemoreceptor. In all, 429 patients deemed to have reduced responsiveness were ultimately randomized to the control group, receiving a maintenance dose of clopidogrel (75 mg), or to a VASP-guided loading dose of up to three additional loading doses of 600 mg every 24 hours until VASP was reduced below 50% pre-PCI.
Thirty-day definite stent thrombosis postprocedure--the primary end point of the study--was significantly reduced in patients in the VASP-guided group as compared with controls, with almost all stent thromboses occurring in the first seven days. There were statistically nonsignificant trends toward reduced cardiovascular death and reduced repeat revascularizations and a significantly reduced risk of MI in the VASP-guided group. Overall MACE was, as a result, significantly lower in the VASP-guided arm of the study. There were no differences in bleeding rates in the VASP-guided group


AHA 2008: New Factor Xa Inhibitor Rivaroxaban Moves Into Phase 3 for ACS
http://www.medscape.com/viewarticle/583315
Lisa Nainggolan : A phase 2 trial with a novel oral factor Xa inhibitor rivaroxaban (Johnson & Johnson/Bayer) has demonstrated the feasibility of triple therapy for patients with acute coronary syndromes, showing a trend toward improved efficacy with the drug in addition to aspirin and clopidogrel. But there was a dose-dependent increase in bleeding using this approach, The ATLAS ACS-TIMI 46 trial identified two doses of rivaroxaban--2.5 mg and 5 mg twice daily--that will be taken forward into a phase 3 trial, Gibson said. This study is slated to begin next month, will enroll up to 16 000 patients, and is estimated to last around 33 months. Rivaroxaban is one of several potential new oral anticoagulants in development that are set to become the long-awaited replacements for warfarin. First indications will be in preventing venous thromboembolism after surgery, but these agents are also being developed for the prevention of stroke in atrial fibrillation patients and, as in this study, for the treatment of ACS. Warfarin has not been used in clinical practice in the setting of ACS, because of the difficulty of keeping patients in the target bleeding range.
The phase 2 ATLAS ACS-TIMI 46 trial, in which 3491 recent ACS patients (who were stabilized one to seven days after the index event) were treated with aspirin alone (n=761) or aspirin plus clopidogrel (n=2730), depending on the preferences of the treating physician. Patients were then further randomized to placebo or rivaroxaban in a number of dosing regimens and treated for six months: 5 mg, 10 mg, or 20 mg of rivaroxaban once daily or 2.5 mg, 5 mg, or 10 mg twice daily.


AHA 2008: JPAD: No Effect of Aspirin Primary-CV-Event Prevention in Diabetics
Steve Stiles
http://www.medscape.com/viewarticle/583346.

Study Highlights
This was a prospective, multicenter, randomized, open-label, controlled trial with blinded end point assessment.
2539 Japanese patients with diabetes without a history of CV disease were randomized to receive low-dose aspirin 81 to 100 mg daily (n = 1262) or no aspirin (n = 1277) for a mean of 4.37 years.
Mean age was 65 years, 55% were men, 20% were current and 40% were past smokers, mean body mass index was 24 kg/m2; median duration of diabetes was 7.3 years in the aspirin and 6.7 years in the nonaspirin group.
Diabetes was well-controlled in both groups with mean glycated hemoglobin levels of 7.1% in the aspirin and 7.0% in the nonaspirin group.
The primary end point was a composite of atherosclerotic events that included fatal and nonfatal ischemic heart disease, fatal or nonfatal stroke, and peripheral arterial disease.
Secondary end points consisted of individual events and mortality from CV and all causes.
Although the study was originally powered to detect a difference in events in the 2 groups, the overall rate of CV events was less than one third of the expected event rate of 52 per 1000 patients.
The dropout rate was 10% in the aspirin group.
The rate if CV events were 5.4% in the aspirin and 6.7% in the nonaspirin group with an HR of 0.80, which was not statistically significant.
Combined fatal coronary and cerebrovascular events were lower in the aspirin group with an HR of 0.10 (P = .0037).
There were no other significant differences in CV outcomes between the 2 groups.
In the subgroup of patients aged 65 years or older, the composite of CV events was 6.3% in the aspirin and 9.2% in the nonaspirin group for a significantly reduced risk (HR, 0.68; P = .047).
In patients younger than 65 years, there was no significant difference in the composite of CV events.
There was no increase in risk for hemorrhagic stroke in the aspirin vs nonaspirin group.
Risk for gastrointestinal bleeding was increased (12 events in the aspirin vs 4 events in the nonaspirin group with 4 cases of severe bleeding requiring transfusion in the aspirin group).
There was no increase in death from hemorrhagic stroke or gastrointestinal bleeding in the aspirin group.
The authors concluded that in contrast to patients without diabetes, use of aspirin for primary prevention was not associated with reduced risk for atherosclerotic events and larger trials with adequate power are needed to confirm this finding.
This finding extends the results of a previous meta-analysis showing lower benefit for CV protection among patients with diabetes vs those without diabetes.
The authors suggested that aspirin use for CV prophylaxis in patients with diabetes should be reexamined.

Cardiologist Questions Safety of Lilly's Prasugrel
http://www.medscape.com/viewarticle/583377\\\
Researchers have overestimated the ability to administer Eli Lilly and Co's experimental antiplatelet agent prasugrel without causing dangerous bleeding, a prominent cardiologist said on Monday.U.S. regulators in recent months have twice delayed a decision on whether to approve prasugrel, which is being developed in partnership with Daiichi Sankyo that would compete with Bristol-Myers Squibb Co's Plavix (clopidogrel).
Prasugrel proved far better able than Plavix to prevent dangerous blood clots in a large trial called Triton whose results were unveiled last year. However, it was associated with a far higher degree of serious bleeding than Plavix, raising concern whether the U.S. Food and Drug Administration would deem its potential benefits worth the risks.The Triton study involved patients who underwent percutaneous coronary interventions.
Researchers of the Lilly-sponsored trial had theorized that prasugrel could be safely given, as long as it was not taken by three groups shown to have the highest bleeding risk in the trial: patients weighing less than 130 pounds, those aged 75 or older, or those who had previous strokes or TIAs.In Triton, prasugrel was 19% more effective than Plavix in preventing cardiovascular death, nonfatal heart attacks and strokes, but it was 32% more likely to cause serious

THINRS: Home INR Monitoring as Effective as Clinic-Based Care
http://www.medscape.com/viewarticle/583500
Susan Jeffrey
Results of a new randomized comparison shows that weekly home international normalized ratio (INR) monitoring is safe but did not reduce stroke, major bleeds, or death when compared with monthly clinic-based INR testing. Home monitoring did increase the amount of time spent in the target therapeutic range as well as patient satisfaction with anticoagulation therapy, the researchers note.
Warfarin is an effective therapy but only if managed well, Dr. Jacobson pointed out during his presentation. Warfarin is often underutilized, and the quality of management can be poor. Frequent home INR monitoring with weekly patient self-testing is a promising strategy to improve outcomes, he said, because it increases test frequency, which might allow more rapid identification and correction of out-of-target-range INRs, and promotes engagement of patients with their own care.
In this trial, the researchers compared these 2 strategies, weekly patient self-testing (PST), using an interactive voice-response reporting system and Web-based local monitoring, and currently recommended practice: high-quality anticoagulation management (HQACM), with testing carried out monthly at a clinic.
The primary end point was an aggregate of stroke, major bleeds, and death. Over an average of 54 months and 8370 patient-years of follow-up, there were 544 primary end-point events - 237 deaths, 263 major bleeds, and 44 strokes - but there was no statistical difference in the number of events between the intervention groups.
In many cases, INR testing is done by off-site labs without point-of-care testing, and the coordination of how results are communicated first to the physician and then back to the patient is often suboptimal. Ideally, patients should get immediate feedback with this type of point-of-care device to minimize the risk for over- and undercoagulation and allow immediate correction of any problems. To compare patient self-care with a better standard of care than is often offered in the community is to potentially underestimate its benefit.


Experts Identify New Risk Factors for Perioperative Death and Stroke
http://www.medscape.com/viewarticle/583666
Study Highlights
The New York Carotid Artery Surgery Study is a population-based cohort of 9308 carotid endarterectomies performed by 482 surgeons in 167 hospitals on Medicare patients from January 1998 through June 1999 in New York State.
Exclusion criteria included patients with no carotid endarterectomy performed, same-side operations for restenosis, carotid endarterectomy combined with other major procedures, and patients without complete clinical risk factor data.
Detailed clinical data were abstracted from medical charts to assess sociodemographic, neurologic, and comorbidity risk factors.
Deaths and strokes within 30 days of surgery were confirmed by clinicians.
Multivariable logistic regression was used to identify independent patient risk factors.
Results demonstrated that the mean age was 74.6 ± 6.8 years (age range, 40 - 98 years), and 44.3% were women.
The indications for surgery included 71.5% of patients were asymptomatic, 18.9% had a carotid TIA, 9.3% had a stroke, and 0.3% had an acute syndrome.
95.4% underwent surgery for high-grade carotid stenosis (70% - 99%).
Within the 30 days of surgery, there were 106 deaths (1.14%) and 305 (3.28%) strokes.
The 30-day rate of death or stroke in asymptomatic patients was 3.01% vs 6.44% for symptomatic patients (P < .0001; OR for symptomatic patients, 2.22; 95% CI, 1.80 - 2.74). The 30-day rate of death or stroke was 2.71% in asymptomatic patients with no history of stroke or TIA, 4.06% in asymptomatic patients with a history of stroke or TIA, 5.62% in those undergoing surgery for carotid TIA, 7.89% of those with stroke, and 13.33% in those with crescendo TIA or stroke-in-evolution. In asymptomatic patients, those with a history of stroke or TIA had higher risks for combined death or stroke vs those with no history of cerebrovascular disease (4.06% vs 2.71%; P < .007). In symptomatic patients, those with stroke as the indication for surgery had a higher risk for complication vs those with TIA (7.89% vs 5.62%; P < .02; OR, 2.44; CI, 1.04 - 1.98). Significant multivariable predictors of death or stroke included age 80 years or older (OR, 1.30; 95% CI, 1.03 - 1.64), nonwhite (OR, 1.83; 95% CI, 1.23 - 2.72), admission from the emergency department (OR, 1.95; 95% CI, 1.50 - 2.54), asymptomatic but with a history of stroke or TIA (OR, 1.40; 95% CI, 1.02 - 1.94), TIA as an indication for surgery (OR, 1.81; 95% CI, 1.39 - 2.36), stroke as the indication (OR, 2.40; 95% CI, 1.74 - 3.31), crescendo TIA or stroke-in-evolution (OR, 3.61; 95% CI, 1.15 - 11.28), contralateral carotid stenosis 50% or more (OR, 1.44; 95% CI, 1.15 - 1.79), severe disability (OR, 2.94; 95% CI, 1.91 - 4.50), coronary artery disease (OR, 1.51; 95% CI, 1.20 - 1.91), and diabetes with insulin treatment (OR, 1.55; 95% CI, 1.10 - 2.18). The presence of a deep carotid ulcer was of borderline significance (OR, 2.08; 95% CI, 0.93 - 4.68). Limitations to this study were bias associated with an observational cohort study and no standard approach to presurgical or postsurgical assessment. Genomewide Association Study Finds Genetic Predictors of Warfarin Required Dose
http://www.medscape.com/viewarticle/583686

Genomewide association studies have identified another gene variant that influences individual variations in response to warfarin dosage. Warfarin, described as the 11th most widely prescribed drug worldwide, is an effective anticoagulant used in patients with stroke, myocardial infarction, and pulmonary embolism. However, among whites, the required dosage varies 10- to 20-fold between individuals. A dose that creates bleeding problems in some patients may fail to protect others against clotting disorders.
The clinical index of appropriate warfarin dose is a coagulation level known as the prothrombin time international normalized ratio (INR). The INR for a healthy person is 1.0, but for patients taking warfarin to reduce clotting, the target INR is 2.0 to 3.0. Lacking predictive information about genetic and nongenetic factors influencing a patient's warfarin response, physicians determine doses empirically and initially may err in either direction.
Polymorphisms in VKORC1, the drug target of warfarin, may alter gene expression and explain approximately 30% of variation in warfarin response. Variants in CYP2C9, a gene coding for a liver enzyme that metabolizes warfarin, account for about 12% of the dose variation. Factors such as age and sex explain another 15% of the variation. A study in press, involving 1523 Swedish patients, assessed patient benefits of forecasting the required warfarin dose.
The current GWAS genotyped 1053 Swedish patients in the Warfarin Genetics (WARG) cohort and determined the mean warfarin dosage required to establish an INR of 2.0 to 3.0 in each subject. Doses ranged from 5.0 to 107.0 mg/week. Univariate regression analysis found VKORC1 and CYP2C9, previously identified, and multiple regression analysis identified a third gene associated with response to warfarin: CYP4F2 (P = 8.3 x 10î º10). The single-nucleotide polymorphism (SNP) alters the coding sequence for the gene product.
Clinical trials are currently underway to determine whether genetic prediction of dose benefits patients, and there is evidence that it does. The FDA recommends, but does not mandate, that genetic information should be considered in deciding the warfarin dose. "Our GWAS, at this point, lays out what the genetic landscape looks like, and gives more impetus to conducting trials showing that CYP2C9, VKORC1, [and] CYP4F2 are the major genetic predictors," said Dr. McGinnis. "There may be some other ones that we will find ... It's not perfect, but it's a lot better than doing it empirically, adjusting by trial and error."
Genetic coding in the genes VKORC1, CYP2C9, and CYP4F2 explain 30%, 12%, and 1.5%, respectively, of the variance in the warfarin dose required to achieve an INR of 2.0 to 3.0, while other genes may account for 3% to 5% more of the variance.
The other factors that account for about 15% of the variation in warfarin dosage to achieve an INR of 2.0 to 3.0, which can be a dosage that ranges from 5.0 - 107.0 mg/week, include age and sex.

Admission INR Inversely Associated With Infarct Volume in Ischemic Stroke
S. Andrew Josephson, M.D.
http://www.medscape.com/viewarticle/583094
Current treatment of acute stroke focuses on administration of lytic medications and endovascular techniques meant to restore blood flow quickly in order to decrease the volume of irreversible tissue injury. An alternative strategy is for patients at high risk for ischemic stroke to be taking medications at the time of the event that will reduce infarct size. A recent trial aimed to study whether the preadmission international normalized ratio (INR) in patients taking warfarin was associated with decreased stroke severity.
The authors performed a single institution retrospective analysis of consecutive patients taking warfarin at the time of admission for ischemic stroke, all of whom received diffusion-weighted brain MRI within 24 h of symptom onset. A total of 93 patients were identified and another 93 patients not taking warfarin during the same time period, matched for stroke subtype, served as a control. The indication for warfarin use in the cohort was most commonly nonvalvular atrial fibrillation (61 patients, 66%). The median time to INR measurement from stroke symptom onset was 6.1 h, and the median time from INR measurement to MRI was 1.6 h.
The median INR in patients with warfarin use at the time of stroke was 1.7 (IQR, 1.3-2.3) and the mean admission infarct volume on MRI was 7.9 mL (IQR, 1.9-25.1 mL). There was a significant inverse correlation between INR values on admission and infarct volume (r = -0.38, p < .001), which remained significant after a linear regression model accounted for other predictors (p = .014). When patients were dichotomized into those with INR ≤ 2.0 and those ≥ 2.0, those ≤ 2.0 were found to have 3.5 times (95% CI, 2.9-4.2) greater lesion volume than those with INR ≥ 2.0. Patients with therapeutic (≥ 2.0) INR levels on admission had a significantly smaller lesion volume than the control group not taking warfarin (p =.001). However, the difference between lesion volume in all patients taking warfarin, regardless of INR, and the control group did not quite reach statistical significance (p = .072). Additional secondary analyses demonstrated that admission INR was inversely correlated with final infarct volume seen on follow-up MRI performed between days 5 and 75 (n = 40, r = -0.42, p = .007). The severity of stroke at admission, measured by the National Institutes of Health Stroke Scale (NIHSS), and the degree of disability at discharge, measured by the modified Rankin Scale (mRS), were also inversely correlated with admission INR in the group taking warfarin. Currently, there are few evidence-based indications for use of warfarin for primary or secondary stroke prevention outside of atrial fibrillation. However, even in patients with atrial fibrillation, only about half of patients with an indication for warfarin are prescribed for it, and in those who are, the INR is frequently found to be subtherapeutic. This study once again emphasizes that these patients should be taking warfarin at the appropriate dose, not only to prevent stroke, but also to limit the size and severity of stroke when it occurs. For the clinician, this important study provides further convincing information to discuss with patients and their physicians who are considering initiating warfarin therapy for evidence-based indications. Zosia Chustecka http://www.medscape.com/viewarticle/583771
Bevacizumab is a monoclonal antibody that neutralizes vascular endothelial gro
Bevacizumab Significantly Increases Venous Thromboembolism Risk
wth factor (VEGF), which results in the inhibition of angiogenesis.The angiogenesis inhibitor bevacizumab (Avastin, Genentech/Roche) significantly increases the risk for venous thromboembolism (VTE), a new meta-analysis concludes. Because the drug is being increasingly used in the routine treatment of cancer patients, the authors suggest that this new finding might merit a black-box warning.Currently, the product information includes only arterial thromboembolic events in its warnings section. That finding comes from a meta-analysis of 5 clinical trials involving 1745 patients, which did not find an increase in the risk of VTE (J Natl Cancer Inst. 2007;99:1232-1239).

The new meta-analysis examined 15 randomized controlled clinical trials involving 7956 patients with various advanced cancers, and found that the risk of developing VTE for patients taking bevacizumab was 33% greater than for controls (relative risk, 1.33; 95% confidence interval, 1.13 - 1.56; P < .001). The other issue for clinicians and researchers is whether the background rate of VTE (independent of any increase related to bevacizumab) justifies the prophylactic use of anticoagulants more broadly, Dr. Hurwitz said. This is an issue that merits further study, he added. It is also a rather controversial subject, and is hotly debated by oncologists, most recently at the 33rd European Society of Medical Oncology Congress in Stockholm, Sweden, as reported at the time by Medscape Oncology. According to Genentech/Roche, the manufacturer of bevacizumab, the incidence of VTEs reported in this meta-analysis is consistent with the drug's safety profile as documented in the product label and in previously presented data. "VTEs are typically managed with anticoagulant medication and can occur in people with cancer, regardless of the treatment they are receiving for their cancer," the company sai The meta-analysis found that bevacizumab increased the risk not only for all-grade VTE, but also for clinically significant high-grade VTE, the authors point out. The incidence was 11.9% for all-grade VTE and 6.3% for high-grade VTE. In addition, the risk was significantly and similarly increased by both the low dose (2.5 mg/kg per week) and the high dose (5 mg/kg per week). However, there was difference in the risk seen among patients with different types of tumors. The highest incidence of all-grade VTE was observed among patients with colorectal cancer (19.1%), whereas the lowest risk was seen in patients with renal cancer (3%). In between were patients with non-small-cell lung cancer (14.9%) and patients with breast cancer (7.3%). A similar pattern across these tumor types was seen with the incidence of high-grade VTE. This difference in VTE by cancer may be related to biology (for example, higher incidence in aerodigestive malignancies), but may also reflect other factors, such as previous treatment and performance status, say the authors.The authors point out several limitations to their meta-analysis, including potential overlap between the various grades of VTE, and the fact that the incidence of VTE varied greatly across the individual clinical trials (ranging Thrombolytic Therapy Can Improve Survival for Some Patients With Acute Embolism
http://www.medscape.com/viewarticle/583818
Thrombolytic therapy improves survival for some patients with massive acute pulmonary embolisms (PE), but may increase mortality for others, according to a report in the November 10th issue of the Archives of Internal Medicine.Only 356 (2.4%) of the 15,116 patients in the database received thrombolytic therapy for acute PE, the results indicate.
Overall, the unadjusted 30-day mortality rate was 2.2-fold higher among patients who received thrombolytic therapy (17.4%) than among those who did not receive this treatment (8.6%), the authors report.Results were similar for in-hospital mortality rates, which were 2.3-fold higher for patients who received thrombolytic therapy (19.6 per 1000 person-days) than for those who did not receive thrombolytic therapy (8.3 per 1000 person-days).
There was, however, a trend toward lower mortality rates among patients in the highest risk categories (based on the predicted probability of receiving thrombolysis), the researchers note. Major bleeding rates were only slightly higher among patients who received thrombolytic therapy (5.3%) than among those who did not (3.5%), the report indicates."
Arch Intern Med 2008;168:2183-2190.

Dipyridamole and Aspirin Combo Reduces Vascular Events
http://www.medscape.com/viewarticle/583873
According to pooled data from randomized controlled trials, dipyridamole and aspirin are more effective than aspirin alone in the secondary prevention of transient ischemic attack (TIA) or minor stroke, researchers report in the November issue of the Journal of Neurology, Neurosurgery and Psychiatry.Compared to the use of aspirin alone, the adjusted hazard ratio for the composite end-point of vascular death, non-fatal myocardial infarction or non-fatal stroke was 0.82 in the combination group.
This continued to be true in a variety of subgroups, including those based on age, sex, hypertension, diabetes, and previous stroke. The researchers, however, point out that data on risk factors were not available for all five trials, thus reducing the numbers available for analysis.
The combination was also more effective than aspirin alone in preventing recurrent stroke (hazard ratio, 0.78).
The superiority of the agents in concert, the investigators observe, is backed by sound evidence. Combination therapy, they conclude, "should be preferred over aspirin after a TIA or minor stroke of presumed arterial origin, as supported by several national guidelines."
J Neurol Neurosurg Psychiatry 2008;79:1218-1223.

Lower-Than-Expected Bleeding in CABG Patients Taking Clopidogrel Within Five Days Preop
http://www.medscape.com/viewarticle/584123
Shelley Wood
A new comparison of CABG patients who did and did not receive clopidogrel (Plavix, Bristol-Myers Squibb/Sanofi Pharmaceuticals) within five days prior to their surgeries is challenging some of the long-held concerns about bleeding risks in CABG patients. Authors of the analysis found that clopidogrel within five days of CABG was "weakly associated" with an increased need for red blood cell transfusions, but they were no more likely to require reoperation for bleeding than people who had taken it more than five days beforehand.
What's more, many other factors, including which surgeon performed the procedure, female sex, and whether cardiopulmonary bypass was used, were all bigger determinants of bleeding risk than clopidogrel use five days or less before surgery.
The dilemma is posed in part by existing AHA/ACC guidelines, which give clopidogrel a class 1 recommendation for patients with non-ST-elevation ACS but also advise, as a class 1 recommendation, that clopidogrel be withheld for five days before CABG, if clinical circumstances permit it. Surgeons at many centers are resistant to performing what are more dangerous and technically demanding procedures when patients have recently taken clopidogrel.
Bleeding Events, With and Without Recent Clopidogrel

Clopidogrel <5 days (%)
No clopidogrel <5 days (%)
Reoperation for bleeding
Clopidogrel at five days or less was significantly associated with a 40% increased need for red cell transfusion, but this association was weaker than other things assessed by the investigators. In a statistical analysis that assessed the relative statistical strength of different predictive factors, which surgeon performed the procedure was by far the strongest predictor of whether a patient required red blood cell transfusion.
Kim JH-J, Newby K, Clare RM et al. Clopidogrel use and bleeding after coronary artery bypass graft surgery. Am Heart J 2008; 156:886-892.

Donna Castellone

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Donna Castellone,
MS, MT(ASCP)SH
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