Comparison of the usefulness of enoxaparin versus warfarin for prevention of left ventricular mural thrombus after anterior wall acute myocardial infarction.

Left ventricular (LV) thrombus is one of the most common complications in patients with anterior acute myocardial infarction (AMI) and LV dysfunction. Although anticoagulation is frequently prescribed, data regarding the appropriate drug, duration, risks, and effect on echocardiographic indices of thrombus are lacking. Moreover, given the difficulty in obtaining adequate anticoagulation with warfarin, it is possible that short-term treatment with a more predictable agent would be effective. We randomized 60 patients at high risk of developing LV mural thrombus (anterior acute myocardial infarction with Q waves and ejection fraction≤40%) to receive either enoxaparin 1 mg/kg (maximum 100 mg) subcutaneously every 12 hours for 30 days or traditional anticoagulation (intravenous heparin followed by oral warfarin for 3 months). Clinical evaluations and transthoracic echocardiograms were obtained at baseline, in-hospital, and at 3.5 months. There were no differences between the groups regarding baseline demographics, acute echocardiographic findings, and in-hospital outcomes. The length of hospital stay tended to be shorter for the enoxaparin group (4.6 vs 5.6; p=0.066) and the corresponding hospital costs ($25,837 vs $34,666; p=0.18). At 3 months, bleeding and thromboembolic events were rare and similar between enoxaparin and warfarin groups. Although more patients had probable mural thrombus in the enoxaparin group compared with warfarin at 3.5 months (15% vs 4%; p=0.35), this was not significantly different. In conclusion, the use of enoxaparin tends to shorten hospitalization and lower cost of care. However, at 3.5 months, there appears to be numerically higher (but statistically insignificant) rates of LV thrombus in the enoxaparin group.

Incidence and prognostic impact of gastrointestinal bleeding after percutaneous coronary intervention for acute myocardial infarction.

We examined the incidence, presentation, and outcome of patients who developed gastrointestinal bleeding after percutaneous coronary intervention for acute myocardial infarction in the Primary Angioplasty in Myocardial Infarction trials. Of the 3,130 patients, 71 (2.3%) developed gastrointestinal bleeding, which was more likely to occur in elderly patients. Gastrointestinal bleeding was independently associated with a prolonged hospital stay and greater in-hospital and 6-month mortality.

Primary angioplasty in acute myocardial infarction at hospitals with no surgery on-site (the PAMI-No SOS study) versus transfer to surgical centers for primary angioplasty.

OBJECTIVES: To investigate primary angioplasty (PA) for high-risk acute myocardial infarction (AMI) at hospitals with no cardiac surgery on-site (No SOS), we hypothesized that a nonrandomized registry of such patients treated with PA would show clinical outcomes similar to those of a group randomized to transfer for PA, and that reperfusion would occur faster. BACKGROUND: Primary angioplasty provides outcomes superior to fibrinolytic therapy in AMI, but its use in community hospitals with No SOS has been limited. METHODS: Fibrinolytic-eligible patients with high-risk AMI prospectively consented if they had one or more high-risk characteristic. Nineteen hospitals with No SOS prospectively enrolled 500 patients for PA on-site. Seventy-one similar Air Primary Angioplasty in Myocardial Infarction trial patients were randomized to transfer for PA. RESULTS: Primary angioplasty was performed in 88% of patients. Patients transferred for PA had a longer mean time to treatment (187 vs. 120 min; p < 0.0001). Thrombolysis In Myocardial Infarction (TIMI) flow grade 3 was achieved in 96% for on-site PA, 86% in the transfer group (p = 0.004). The combined primary end point of 30-day mortality, re-infarction, and disabling stroke occurred in 27 (5%) on-site PA patients and 6 (8.5%) transfer patients (p = 0.27). Unadjusted one-year mortality was improved in on-site PA patients compared with those transferred (6% vs. 13%, p = 0.043), but after adjustment for differences in baseline variables, this difference was not significant. CONCLUSIONS: On-site PA and transfer groups had similar 30-day outcomes and more rapid reperfusion for on-site PA. Primary angioplasty in high-risk AMI patients at hospitals with No SOS is safe, effective, and faster than PA after transfer to a surgical facility.

Does beta-blocker therapy improve clinical outcomes of acute myocardial infarction after successful primary angioplasty?

OBJECTIVES: We sought to determine if beta-blocker therapy improves clinical outcomes of acute myocardial infarction (AMI) after successful primary percutaneous coronary intervention (PCI). BACKGROUND: We have shown that pre-treatment with beta-blockers has a beneficial effect on short-term clinical outcomes in patients undergoing primary PCI for AMI. It is unknown if beta-blocker therapy after successful primary PCI improves prognosis of AMI. METHODS: We analyzed clinical, angiographic, and outcomes data in 2442 patients who underwent successful primary PCI in the Primary Angioplasty in Acute Myocardial Infarction-2 (PAMI-2), PAMI No Surgery-on-Site (PAMI noSOS), Stent PAMI, and Air PAMI trials. We classified patients into beta group (those who received beta-blockers after successful PCI, n = 1661) and no-beta group (n = 781). We compared death and major adverse cardiac events (MACE) (death, reinfarction, and ischemia-driven target vessel revascularization) at six months between groups receiving and not receiving beta-blockers. RESULTS: At six months, beta patients were less likely to die (2.2% vs. 6.6%, p < 0.0001) or experience MACE (14 vs. 17%, p = 0.036). In multivariate analysis, beta-blockers were independently associated with lower six-month mortality (odds ratio [OR] 0.43, 95% confidence interval [CI] 0.26 to 0.73, p = 0.0016). Beta-blocker therapy was an independent predictor of lower six-month events in high-risk subgroups: ejection fraction

The incidence, predictors, and outcomes of early reinfarction after primary angioplasty for acute myocardial infarction.

OBJECTIVES: We sought to identify the incidence, predictors, and clinical consequences of one-month reinfarction (RE-MI) in patients undergoing primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI). BACKGROUND: One-month reinfarction after AMI significantly increases long-term mortality; however, little is known about the incidence and predictors of RE-MI in patients undergoing primary angioplasty. METHODS: We analyzed data from 3,646 patients who underwent primary PCI in the Primary Angioplasty in Acute Myocardial Infarction (PAMI) studies. We studied the incidence, correlates, and clinical outcomes of 30-day RE-MI. RESULTS: Reinfarction within one month of index hospitalization occurred in 77 (2.1%) of patients. In multivariate analysis, admission Killip class >1 (odds ratio [OR] 2.02, 95% confidence interval [CI] 1.09 to 3.76), left ventricular ejection fraction <50% (OR 2.49, 95% CI 1.30 to 4.74), final coronary stenosis >30% (OR 2.57, 95% CI 1.28 to 5.15), and presence of coronary dissection (OR 2.40, 95% CI 1.36 to 4.24) and thrombus (OR 2.36, 95% CI 1.23 to 4.53) on the final angiogram were independent correlates of RE-MI. One-month reinfarction was independently associated with death (OR 7.14, 95% CI 3.28 to 15.5) and ischemic target vessel revascularization (I-TVR) (OR 15.0, 95% CI 8.68 to 26.0) at six months. CONCLUSIONS: We conclude that, although early RE-MI is uncommon in patients treated by primary PCI, it is a significant independent predictor of death and I-TVR at six months. Admission Killip class >1 and left ventricular systolic dysfunction were associated with higher incidence of RE-MI. Our results suggest that optimal revascularization during primary PCI may decrease RE-MI rates.

A randomized trial of transfer for primary angioplasty versus on-site thrombolysis in patients with high-risk myocardial infarction: the Air Primary Angioplasty in Myocardial Infarction study.

OBJECTIVES: The Air Primary Angioplasty in Myocardial Infarction (PAMI) study was designed to determine the best reperfusion strategy for patients with high-risk acute myocardial infarction (AMI) at hospitals without percutaneous transluminal coronary angioplasty (PTCA) capability. BACKGROUND: Previous studies have suggested that high-risk patients have better outcomes with primary PTCA than with thrombolytic therapy. It is unknown whether this advantage would be lost if the patient had to be transferred for PTCA, and reperfusion was delayed. METHODS: Patients with high-risk AMI (age >70 years, anterior MI, Killip class II/III, heart rate >100 beats/min or systolic BP <100 mm Hg) who were eligible for thrombolytic therapy were randomized to either transfer for primary PTCA or on-site thrombolysis. RESULTS: One hundred thirty-eight patients were randomized before the study ended (71 to transfer for PTCA and 67 to thrombolysis). The time from arrival to treatment was delayed in the transfer group (155 vs. 51 min, p < 0.0001), largely due to the initiation of transfer (43 min) and transport time (26 min). Patients randomized to transfer had a reduced hospital stay (6.1 +/- 4.3 vs. 7.5 +/- 4.3 days, p = 0.015) and less ischemia (12.7% vs. 31.8%, p = 0.007). At 30 days, a 38% reduction in major adverse cardiac events was observed for the transfer group; however, because of the inability to recruit the necessary sample size, this did not achieve statistical significance (8.4% vs. 13.6%, p = 0.331). CONCLUSIONS: Patients with high-risk AMI at hospitals without a catheterization laboratory may have an improved outcome when transferred for primary PTCA versus on-site thrombolysis; however, this will require further study. The marked delay in the transfer process suggests a role for triaging patients directly to specialized heart-attack centers.