Faculty Bibliography

BACKGROUND: Clinical trials of antithrombotic agents for the treatment of ACS routinely assess bleeding as a safety endpoint, but variation in bleeding definitions makes comparison of the relative safety of these agents difficult. METHODS: The ABC Multidisciplinary Working Group, an informal working group comprising clinical researchers and representatives from the US Food and Drug Administration, the National Institutes of Health, and the pharmaceutical industry, sought to develop a consensus approach to measuring the incidence and severity of bleeding complications during clinical trials of acute coronary syndromes (ACS). A meeting of the ABC was convened in April 2008 in Washington, DC, with the goal of developing a consensus approach to measuring the incidence and severity of hemorrhagic complications during clinical trials of ACS. Relevant literature on bleeding was reviewed through a series of short lectures and intensive group discussion. RESULTS: Using existing evidence on bleeding and outcomes as well as clinical judgment, criteria for the assessment of bleeding were developed through expert consensus. This consensus statement divides bleeding-related data elements into three categories: essential, recommended, and optional. CONCLUSIONS: The ABC Group recommendations for collection and reporting of bleeding complications provide a framework for consistency in the collection of information on hemorrhagic complications in trials of ACS. Widespread adoption of the statement recommendations will facilitate understanding of the mechanisms of adverse outcomes after bleeding and comparisons of the relative safety of antithrombotic agents, as well as the interpretation of safety results from future studies.

BACKGROUND:Currently recommended anticoagulant agents used in the setting of percutaneous coronary intervention (PCI) inhibit, with varying degrees of intensity, 2 critical targets (factor Xa and/or IIa) of the coagulation cascade, yet they carry significant limitations. M118-a novel, rationally engineered heparin-provides consistent anti-Xa and anti-IIa activity with a constant anti-Xa:anti-IIa ratio over time. M118 also combines the desired anticoagulant effects of unfractionated heparin with the beneficial attributes of low-molecular-weight heparin, and may represent the next generation of heparin therapy in patients diagnosed with acute coronary syndrome. STUDY DESIGN/METHODS:The EMINENCE trial is a prospective, randomized, open-label, multicenter phase 2 study that will evaluate the safety and feasibility of M118 as an anticoagulant versus unfractionated heparin in subjects with stable coronary artery disease undergoing PCI. The primary end point of the study will be the combined incidence of clinical events defined as the composite of 30-day death, myocardial infarction, repeat revascularization, catheter thrombus, stroke, thrombocytopenia, bailout use of glycoprotein IIb/IIIa inhibitors, and major or minor bleeding. CONCLUSION/CONCLUSIONS:The EMINENCE trial will assess the safety and feasibility of M118 as an anticoagulant in the setting of PCI and will provide important information to determine the appropriate therapeutic range of activated clotting time for M118 and the appropriate dose or doses to be explored in a phase 3 clinical trial.

BACKGROUND:Interest in the biology of endogenous progenitor cells (EPCs) continues to grow as evidence of their role in vascular repair mounts. EPC enumeration requires specialized laboratory techniques and is performed immediately after sample acquisition, limiting the clinical contexts in which EPC enumeration can be performed and the ability to increase sample sizes through multi-center participation. METHODS:We compared the numbers of EPCs enumerated in samples processed immediately after acquisition (n = 36) with EPCs enumerated in specimens stored for 24 hours or after cryopreservation of mononuclear cells (MNC) using two EPC identification strategies: cell surface marker expression (CD133/CD34) and aldehyde dehydrogenase activity (ALDH(br) cells). RESULTS:EPCs assessed in fresh samples correlated with EPCs enumerated after whole blood storage (r = 0.699 for CD133(+)CD34(+) cells, r = 0.880 for ALDH(br) cells, P < 0.005 and P < 0.0001, respectively) or mononuclear cryopreservation (r = 0.590 for CD133(+)CD34(+) cells, r = 0.894 for ALDH(br) cells, P < 0.0001 for each); however, correlation based on assessment of ALDH(br) cells was higher (P < 0.0003 for comparison of correlation coefficients). Initial results from a multi-site clinical trial suggest that EPC enumeration after mononuclear cell cryopreservation is feasible. CONCLUSION/CONCLUSIONS:EPC analysis based on ALDH activity is reproducible, even after extended whole blood storage or MNC cryopreservation.

Antiplatelet therapy is the cornerstone of management in acute coronary syndromes (ACS) and percutaneous coronary intervention. Combination therapy with aspirin and clopidogrel reduces the risk of death, myocardial infarction, or stroke in ACS but increases the risk of major bleeding, which studies indicate is 1%-4% higher when clopidogrel is added to aspirin. Given the association between bleeding and adverse outcomes, minimizing bleeding risk is a clinical priority. This review outlines strategies to reduce both acute and chronic bleeding risk with aspirin and clopidogrel and focuses on dosing of concomitant therapies, vascular access techniques, and mitigating the bleeding risk associated with coronary artery bypass grafting surgery.

Guidelines support percutaneous coronary intervention (PCI) of the noninfarct-related artery during primary PCI for ST-segment elevation myocardial infarction (STEMI) in patients with hemodynamic compromise; however, in patients without hemodynamic compromise, PCI of the noninfarct-related artery is given a class III recommendation. We analyzed the National Cardiovascular Data Registry (n = 708,481 admissions, 638 sites) to determine the prevalence, predictors, and in-hospital outcomes of primary multivessel PCI from 2004 to 2007. Patients with STEMI and multivessel coronary artery disease who were undergoing primary PCI were identified (n = 31,681). After excluding the patients treated with staged PCI (n = 2,745), 10.8% (n = 3,134) of the remaining population (n = 28,936) were treated with multivessel PCI. Patients undergoing multivessel PCI were at higher risk and were more likely to be in cardiogenic shock. The overall in-hospital mortality rates were greater in patients undergoing multivessel PCI (7.9% vs 5.1%, p <0.01). Among patients with STEMI and cardiogenic shock (n = 3,087), those receiving multivessel PCI had greater in-hospital mortality (36.5% vs 27.8%; adjusted odds ratio 1.54, 95% confidence interval 1.22 to 1.95). In conclusion, these data suggest that performing multivessel PCI during primary PCI for STEMI does not improve short-term survival even for patients with cardiogenic shock. These findings suggest the need for definitive studies to evaluate the utility of noninfarct-related artery PCI among patients with STEMI.

Bleeding complications after percutaneous coronary interventions (PCI) are a significant clinical problem associated with worse patient outcomes, including mortality. A number of studies have demonstrated that the majority of bleeding complications in patients undergoing PCI are related to access-site bleeding. Employing the transradial artery approach to PCI markedly reduces these bleeding rates. The reductions in bleeding and transfusions from employing the transradial approach may be associated with improved survival in PCI patients. Despite these data, the prevalence of transradial PCI remains low and its adoption by operators has been slow to increase. Growing data to support the superior clinical outcomes with radial artery PCI, coupled with improved awareness of this data, may lead to increases in its adoption and improved clinical outcomes and mortality after PCI.

BACKGROUND:Bleeding in patients undergoing percutaneous coronary intervention (PCI) is associated with increased morbidity, mortality, length of hospitalization, and cost. We identified baseline clinical characteristics associated with bleeding complications after PCI and developed a simplified, clinically useful algorithm to predict patient risk. METHODS AND RESULTS/RESULTS:Data were analyzed from 302 152 PCI procedures performed at 440 US centers participating in the National Cardiovascular Data Registry. As defined by the National Cardiovascular Data Registry, bleeding required transfusion, prolonged hospital stay, and/or a drop in hemoglobin >3.0 g/dL from any location, including percutaneous entry site, retroperitoneal, gastrointestinal, genitourinary, and other/unknown location. Bleeding complications occurred in 2.4% of patients. From the best-fitting model consisting of 15 clinical elements associated with post-PCI bleeding in a random 80% training cohort, we developed a parsimonious risk algorithm. Predictors of bleeding included age, gender, previous heart failure, glomerular filtration rate, peripheral vascular disease, no previous PCI, New York Heart Association/Canadian Cardiovascular Society Functional Classification class IV heart failure, ST-elevation myocardial infarction, non-ST-elevation myocardial infarction, and cardiogenic shock. The parsimonious model was validated in the remaining 20% of the population (c-statistic, 0.72) and in clinically relevant subgroups of patients. This simplified model was used to derive a clinical risk algorithm, with larger numbers corresponding with greater risk. In 3 categories, bleeding rates were greater in patients with higher estimates (<or=7, 0.7%; 8 to 17, 1.8%; >or=18, 5.1%). CONCLUSIONS:This report identifies baseline clinical factors associated with bleeding and proposes a clinically useful algorithm to estimate bleeding risk. This model is potentially actionable in altering therapeutic decision making and improving outcomes in patients undergoing PCI.

BACKGROUND: Treatments for non-ST-segment-elevation myocardial infarction (NSTEMI) reduce ischemic events but increase bleeding. Baseline prediction of bleeding risk can complement ischemic risk prediction for optimization of NSTEMI care; however, existing models are not well suited for this purpose. METHODS AND RESULTS: We developed (n=71 277) and validated (n=17 857) a model that identifies 8 independent baseline predictors of in-hospital major bleeding among community-treated NSTEMI patients enrolled in the Can Rapid risk stratification of Unstable angina patients Suppress ADverse outcomes with Early implementation of the ACC/AHA guidelines (CRUSADE) Quality Improvement Initiative. Model performance was tested by c statistics in the derivation and validation cohorts and according to postadmission treatment (ie, invasive and antithrombotic therapy). The CRUSADE bleeding score (range 1 to 100 points) was created by assignment of weighted integers that corresponded to the coefficient of each variable. The rate of major bleeding increased by bleeding risk score quintiles: 3.1% for those at very low risk (score < or = 20); 5.5% for those at low risk (score 21-30); 8.6% for those at moderate risk (score 31-40); 11.9% for those at high risk (score 41-50); and 19.5% for those at very high risk (score >50; P(trend) <0.001). The c statistics for the major bleeding model (derivation=0.72 and validation=0.71) and risk score (derivation=0.71 and validation=0.70) were similar. The c statistics for the model among treatment subgroups were as follows: > or = 2 antithrombotics=0.72; <2 antithrombotics=0.73; invasive approach=0.73; conservative approach=0.68. CONCLUSIONS: The CRUSADE bleeding score quantifies risk for in-hospital major bleeding across all postadmission treatments, which enhances baseline risk assessment for NSTEMI care.