Faculty Bibliography

BACKGROUND:Elinogrel is the only selective, competitive and reversible platelet P2Y(12) inhibitor available in both intravenous (IV) and oral formulations. METHODS AND RESULTS/RESULTS:This substudy of the Intravenous and Oral Administration of Elinogrel to Evaluate Tolerability and Efficacy in Nonurgent Percutaneous Coronary Intervention patients (INNOVATE-PCI) trial evaluated the pharmacokinetic and pharmacodynamic effects of two dosing regimens of IV followed by oral elinogrel (120 mg IV plus 100 mg oral twice daily; 120 mg IV plus 150 mg oral twice daily) versus standard clopidogrel therapy (300-600 mg oral loading dose plus 75 mg oral maintenance dose) in 56 patients undergoing nonurgent PCI. At time of randomization, 71.4% (40/56) of patients were using maintenance clopidogrel therapy. In the acute phase, an IV bolus of elinogrel achieved more rapid and potent antiplatelet effects compared with clopidogrel, which were sustained during the transition from the IV to the oral formulation in the first 24 hours of the peri-PCI period. During chronic therapy, elinogrel achieved similar levels of platelet reactivity compared with clopidogrel before the next oral dose and, although platelet reactivity was lower with elinogrel up to 6 hours after daily oral maintenance dosing, these differences were not statistically significant. These pharmacodynamic effects matched the pharmacokinetic profile of elinogrel. There were no differences in pharmacodynamic and pharmacokinetic effects between the two elinogrel dosing regimens. CONCLUSIONS:Compared with clopidogrel, the combination of IV and oral elinogrel achieves more rapid and enhanced antiplatelet effects that were sustained through the transition to oral elinogrel in the peri-PCI period, but these were not significant during chronic dosing in this pilot investigation. CLINICAL TRIAL REGISTRATION/BACKGROUND:URL: http://www.clinicaltrials.gov. Unique identifier: NCT00751231.

High residual platelet reactivity (HRPR) on clopidogrel is a predictor of recurrent ischemic events in patients undergoing percutaneous coronary interventions (PCI). Significant intraindividual variability in platelet aggregation on repeat testing has been reported. To understand factors contributing to the variability in platelet aggregation testing, we examined clinical and laboratory elements linked to HRPR in 255 consecutive patients tested ≥12 hours after PCI using light transmission aggregometry (LTA) in response to adenosine diphosphate 5 μmol/L and VerifyNow P2Y12 assay (VNP2Y12; Accumetrics). HRPR was defined as >46% residual aggregation for LTA and >236 P2Y12 response units (PRUs) for VNP2Y12. On multivariate analysis the only variable independently associated with HRPR with both LTA and VNP2Y12 was laboratory-defined anemia. Prevalences of HRPR by LTA were 34.3% in anemic patients, 15.6% in patients with normal hemoglobin levels, and 59.8% versus 25.9% by VNP2Y12 (p <0.005 for the 2 comparisons). In a subgroup of 50 patients, testing was done before and after the clopidogrel loading dose. At baseline there were no differences in platelet aggregation with either assay; however, absolute decrease in reactivity after the clopidogrel load was significantly less in anemic patients compared to patients with normal hemoglobin (change in residual aggregation by LTA 15.8 ± 5.8% vs 28.8 ± 3.2%, p <0.05; change in PRU by VNP2Y12 56.5 ± 35.5 vs 145.0 ± 14.2 PRUs, p <0.05, respectively). In conclusion, anemia is an important contributor to apparent HRPR on clopidogrel and may explain some of the intraindividual variability of platelet aggregation testing.

OBJECTIVES/OBJECTIVE:This study sought to assess percutaneous coronary intervention (PCI) for unprotected left main coronary artery (ULMCA) stenosis in routine U.S. clinical practice. BACKGROUND:Percutaneous coronary intervention for ULMCA stenosis is controversial; however, current use and outcomes of ULMCA PCI in routine U.S. clinical practice have not been described. METHODS:We evaluated 5,627 patients undergoing ULMCA PCI at 693 centers within the National Cardiovascular Data Registry Catheterization Percutaneous Coronary Intervention Registry for temporal trends in PCI use (2004 to 2008), patient characteristics, and in-hospital mortality. Thirty-month mortality and composite major adverse events (death, myocardial infarction, and revascularization) with drug-eluting versus bare-metal stents were compared using inverse probability weighted (IPW) hazard ratios (HRs) in a nonrandomized Medicare-linked (age ≥65 years) patient cohort (n = 2,765). RESULTS:ULMCA PCI was performed in 4.3% of patients with ULMCA stenosis. Unadjusted in-hospital mortality rates ranged from 2.9% for elective cases to 45.1% for emergent/salvage cases. By 30 months, 57.9% of the elderly ULMCA PCI population experienced death, myocardial infarction, or revascularization, and 42.7% died. Patients receiving drug-eluting stents (versus bare-metal stents) had a lower 30-month mortality (IPW HR: 0.84, 95% confidence interval [CI]: 0.73 to 0.96), but the composite of major adverse events were similar (IPW HR: 0.95, 95% CI: 0.84 to 1.06). CONCLUSIONS:In the United States, ULMCA PCI is performed in <5% of patients with ULMCA disease and is generally reserved for those at high procedural risk. Adverse events are common in elderly patients and are related to patient and procedural characteristics, including stent type.

AIMS/OBJECTIVE:Bleeding complications have been associated with short-term mortality in patients with non-ST-segment elevation myocardial infarction (NSTEMI). Their association with long-term outcomes is less clear. This study examines mortality associated with in-hospital bleeding during NSTEMI over time intervals starting from hospital discharge and extending past 3 years. METHODS AND RESULTS/RESULTS:We studied 32 895 NSTEMI patients aged ≥65 years, using patient-level data from the CRUSADE registry linked with Medicare claims data. We assessed the association of in-hospital major bleeding with short (30 days), intermediate (1 year), and long-term (3 years) mortality among hospital survivors overall, as well as in those patients treated with or without a percutaneous coronary intervention (PCI). We calculated adjusted hazard ratios (HRs) for mortality for bleeders vs. non-bleeders over time intervals from: (i) discharge to 30 days; (ii) 31 days to 1 year; (iii) 1 year to 3 years; and (iv) beyond 3 years. Overall, 11.9% (n = 3902) had an in-hospital major bleeding event. Cumulative mortality was higher in those who had a major bleed vs. those without at 30 days, 1 year, and 3 years. Even after adjustment, major bleeding continued to be significantly associated with higher mortality over time in the overall population: (i) discharge to 30 days [adjusted HR 1.33; 95% confidence interval (CI) 1.18-1.51]; (ii) 31 days to 1 year (1.19; 95% CI 1.10-1.29); (iii) 1 year to 3 years (1.09; 95% CI 1.01-1.18), and (iv) attenuating beyond 3 years (1.14; 95% CI 0.99-1.31). In-hospital bleeding among patients treated with PCI continued to be significantly associated with higher adjusted mortality even beyond 3 years (1.25; 95% CI 1.01-1.54). CONCLUSION/CONCLUSIONS:In-hospital major bleeding is associated with short-, intermediate-, and long-term mortality among older patients hospitalized for NSTEMI-this association is strongest within the first 30 days, but remains significant long term, particularly among PCI-treated patients. Despite a probable early hazard related to bleeding, the longer duration of risk in patients who bleed casts doubt on its causal relationship with long-term mortality. Rather, major bleeding likely identifies patients with an underlying risk for mortality.

BACKGROUND:Prior studies have suggested that blacks with acute ST-segment-elevation myocardial infarction have increased bleeding risks with fibrinolysis relative to whites, yet these data were quite limited. Additionally, it is unknown whether there are racial differences in bleeding risks among patients with ST-segment-elevation myocardial infarction receiving primary percutaneous coronary intervention. METHODS AND RESULTS/RESULTS:We evaluated data on blacks and whites with ST-segment-elevation myocardial infarction treated with either fibrinolysis or primary percutaneous coronary intervention from the National Registry of Myocardial Infarction (NRMI)-4 and 5 participating centers between July 2000 and December 2006. We compared differences between the 2 groups in rates of in-hospital major bleeding and mortality, adjusted with logistic regression analyses. In fibrinolytic-treated patients with ST-segment-elevation myocardial infarction, the bleeding rates were higher among blacks (n=2283) than whites (n=42 243; 10.9% versus 10.3%; adjusted odds ratio, 1.21; 95% confidence interval, 1.02-1.43). Similarly, in patients receiving primary percutaneous coronary intervention, the bleeding rates were higher in blacks (n=2826) than in whites (n=46 332; 10.3% versus 7.8%; adjusted odds ratio, 1.33; 95% confidence interval, 1.13-1.56). Bleeding was associated with higher risk of death in both ethnic groups. However, there was no overall racial difference in in-hospital mortality among those with bleeding or without bleeding treated with either fibrinolysis or primary percutaneous coronary intervention. CONCLUSIONS:Blacks with ST-segment-elevation myocardial infarction treated with either fibrinolysis or primary percutaneous coronary intervention had a higher risk of bleeding events than their white counterparts. Bleeding was associated with a similar increased risk of death in both ethnic groups treated by either reperfusion strategy.

The adoption of transradial coronary angiography and coronary intervention is growing because of emerging data on its potential advantages over the femoral approach. As the adoption of radial procedures increases, it is important to understand the remaining challenges of both the technique and its implementation. In this review, we discuss four important issues related to transradial procedures--radial access site bleeding, radial artery injury and occlusion, radiation exposure, and implementation of a successful transradial primary percutaneous coronary intervention (PCI) programme. Although the radial artery is superficial and haemostasis can be achieved readily, access site bleeding can occur that, if left unchecked, can lead to forearm haematoma and, rarely, to compartment syndrome. Radial artery injury and occlusion are consequences of radial access, and randomized trials show that use of smaller diameter sheaths, adequate anticoagulation, and post-procedure 'patent' haemostasis reduce the risk of occlusion. The published literature demonstrates an association between transradial procedures and increased radiation exposure; therefore, reduction of radiation dosing during transradial procedures should be a priority for operators and catheterization laboratories. The potential reduction in mortality seen with transradial primary PCI must be balanced against the clinical imperative of timely reperfusion. Operators and catheterization laboratories should not begin a transradial primary PCI programme until sufficient radial experience has been gained in the elective setting. In addition, a protocol for femoral bailout should be considered to maintain door-to-reperfusion metrics.

DESCRIPTION/METHODS:Although approximately 85 million units of red blood cells (RBCs) are transfused annually worldwide, transfusion practices vary widely. The AABB (formerly, the American Association of Blood Banks) developed this guideline to provide clinical recommendations about hemoglobin concentration thresholds and other clinical variables that trigger RBC transfusions in hemodynamically stable adults and children. METHODS:These guidelines are based on a systematic review of randomized clinical trials evaluating transfusion thresholds. We performed a literature search from 1950 to February 2011 with no language restrictions. We examined the proportion of patients who received any RBC transfusion and the number of RBC units transfused to describe the effect of restrictive transfusion strategies on RBC use. To determine the clinical consequences of restrictive transfusion strategies, we examined overall mortality, nonfatal myocardial infarction, cardiac events, pulmonary edema, stroke, thromboembolism, renal failure, infection, hemorrhage, mental confusion, functional recovery, and length of hospital stay. RECOMMENDATION 1: The AABB recommends adhering to a restrictive transfusion strategy (7 to 8 g/dL) in hospitalized, stable patients (Grade: strong recommendation; high-quality evidence). RECOMMENDATION 2: The AABB suggests adhering to a restrictive strategy in hospitalized patients with preexisting cardiovascular disease and considering transfusion for patients with symptoms or a hemoglobin level of 8 g/dL or less (Grade: weak recommendation; moderate-quality evidence). RECOMMENDATION 3: The AABB cannot recommend for or against a liberal or restrictive transfusion threshold for hospitalized, hemodynamically stable patients with the acute coronary syndrome (Grade: uncertain recommendation; very low-quality evidence). RECOMMENDATION 4: The AABB suggests that transfusion decisions be influenced by symptoms as well as hemoglobin concentration (Grade: weak recommendation; low-quality evidence).