Faculty Bibliography

This chapter about antithrombotic therapy for acute myocardial infarction (MI) is part of the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy: Evidence Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs. Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading see Guyatt et al, CHEST 2004; 126:179S-187S). Among the key recommendations in this chapter are the following: For patients with ischemic symptoms characteristic of acute MI of < 12 h in duration, and ST-segment elevation or left bundle-branch block (of unknown duration) on the ECG, we recommend administration of any approved fibrinolytic agent (Grade 1A). We recommend the use of streptokinase, anistreplase, alteplase, reteplase, or tenecteplase over placebo (all Grade 1A). For patients with symptom duration < 6 h, we recommend the administration of alteplase over streptokinase (Grade 1A). For patients with known allergy or sensitivity to streptokinase, we recommend alteplase, reteplase, or tenecteplase (Grade 1A). For patients with acute posterior MI of < 12 h duration, we suggest fibrinolytic therapy (Grade 2C). In patients with any history of intracranial hemorrhage, closed head trauma, or ischemic stroke within past 3 months, we recommend against administration of fibrinolytic therapy (Grade 1C+). For patients with acute ST-segment elevation MI whether or not they receive fibrinolytic therapy, we recommend aspirin, 160 to 325 mg p.o., at initial evaluation by health-care personnel followed by indefinite therapy, 75 to 162 mg/d p.o. (both Grade 1A). In patients allergic to aspirin, we suggest use of clopidogrel as an alternative therapy to aspirin (Grade 2C). For patients receiving streptokinase, we suggest administration of either i.v. unfractionated heparin (UFH) [Grade 2C] or subcutaneous UFH (Grade 2A). For all patients at high risk of systemic or venous thromboembolism (anterior MI, pump failure, previous embolus, atrial fibrillation, or left ventricular thrombus), we recommend administration of IV UFH while receiving streptokinase (Grade 1C+)

OBJECTIVES: We sought to analyze clinical, angiographic, and outcome correlates of hemodynamic parameters in cardiogenic shock. BACKGROUND: The significance of right heart catheterization in critically ill patients is controversial, despite the prognostic importance of the derived measurements. Cardiac power is a novel hemodynamic parameter. METHODS: A total of 541 patients with cardiogenic shock who were enrolled in the SHould we emergently revascularize Occluded Coronaries for cardiogenic shocK (SHOCK) trial registry were included. Cardiac power output (CPO) (W) was calculated as mean arterial pressure x cardiac output/451. RESULTS: On univariate analysis, CPO, cardiac power index (CPI), cardiac output, cardiac index, stroke volume, left ventricular work, left ventricular work index, stroke work, mean arterial pressure, systolic and diastolic blood pressure (all p < 0.001), coronary perfusion pressure (p = 0.002), ejection fraction (p = 0.013), and pulmonary artery systolic pressure (p = 0.047) were associated with in-hospital mortality. In separate multivariate analyses, CPO (odds ratio per 0.20 W: 0.60 [95% confidence interval, 0.44 to 0.83], p = 0.002; n = 181) and CPI (odds ratio per 0.10 W/m(2): 0.65 [95% confidence interval, 0.48 to 0.87], p = 0.004; n = 178) remained the strongest independent hemodynamic correlates of in-hospital mortality after adjusting for age and history of hypertension. There was an inverse correlation between CPI and age (correlation coefficient: -0.334, p < 0.001). Women had a lower CPI than men (0.29 +/- 0.11 vs. 0.35 +/- 0.15 W/m(2), p = 0.005). After adjusting for age, female gender remained associated with CPI (p = 0.032). CONCLUSIONS: Cardiac power is the strongest independent hemodynamic correlate of in-hospital mortality in patients with cardiogenic shock. Increasing age and female gender are independently associated with lower cardiac power

CONTEXT: Enoxaparin has demonstrated advantages over unfractionated heparin in low- to moderate-risk patients with non-ST-segment elevation acute coronary syndromes (ACS) treated with a conservative strategy. OBJECTIVES: To compare the outcomes of patients treated with enoxaparin vs unfractionated heparin and to define the role of enoxaparin in patients with non-ST-segment elevation ACS at high risk for ischemic cardiac complications managed with an early invasive approach. DESIGN, SETTING, AND PARTICIPANTS: The Superior Yield of the New Strategy of Enoxaparin, Revascularization and Glycoprotein IIb/IIIa Inhibitors (SYNERGY) trial was a prospective, randomized, open-label, multicenter, international trial conducted between August 2001 and December 2003. A total of 10 027 high-risk patients with non-ST-segment elevation ACS to be treated with an intended early invasive strategy were recruited. INTERVENTIONS: Subcutaneous enoxaparin (n = 4993) or intravenous unfractionated heparin (n = 4985) was to be administered immediately after enrollment and continued until the patient required no further anticoagulation, as judged by the treating physician. MAIN OUTCOME MEASURES: The primary efficacy outcome was the composite clinical end point of all-cause death or nonfatal myocardial infarction during the first 30 days after randomization. The primary safety outcome was major bleeding or stroke. RESULTS: The primary end point occurred in 14.0% (696/4993) of patients assigned to enoxaparin and 14.5% (722/4985) of patients assigned to unfractionated heparin (odds ratio [OR], 0.96; 95% confidence interval [CI], 0.86-1.06). No differences in ischemic events during percutaneous coronary intervention (PCI) were observed between enoxaparin and unfractionated heparin groups, respectively, including similar rates of abrupt closure (31/2321 [1.3%] vs 40/2364 [1.7%]), threatened abrupt closure (25/2321 [1.1%] vs 24/2363 [1.0%]), unsuccessful PCI (81/2281 [3.6%] vs 79/2328 [3.4%]), or emergency coronary artery bypass graft surgery (6/2323 [0.3%] vs 8/2363 [0.3%]). More bleeding was observed with enoxaparin, with a statistically significant increase in TIMI (Thrombolysis in Myocardial Infarction) major bleeding (9.1% vs 7.6%, P =.008) but nonsignificant excess in GUSTO (Global Utilization of Streptokinase and t-PA for Occluded Arteries) severe bleeding (2.7% vs 2.2%, P =.08) and transfusions (17.0% vs 16.0%, P =.16). CONCLUSIONS: Enoxaparin was not superior to unfractionated heparin but was noninferior for the treatment of high-risk patients with non-ST-segment elevation ACS. Enoxaparin is a safe and effective alternative to unfractionated heparin and the advantages of convenience should be balanced with the modest excess of major bleeding