Clinical features and outcomes of patients with type 2 myocardial infarction: Insights from the Thrombin Receptor Antagonist for Clinical Event Reduction in Acute Coronary Syndrome (TRACER) trial.

BACKGROUND: Type 2 myocardial infarction (MI) is characterized by an imbalance between myocardial blood supply and demand, leading to myocardial ischemia without coronary plaque rupture, but its diagnosis is challenging. METHODS: In the TRACER trial, patients with non-ST-segment elevation acute coronary syndromes were included. We aimed to describe provoking factors, cardiac biomarker profiles, treatment patterns, and clinical outcomes of patients with type 2 MIs. MI events during trial follow-up were adjudicated by an independent clinical events classification committee (CEC) and were classified according to the Third Universal Definition of MI. Using available source documents retrieved as part of the CEC process, we performed a retrospective chart abstraction to collect details on the type 2 MIs. Cox regression models were used to explore the association between MI type (type 1 or type 2) and cardiovascular death. RESULTS: Overall, 10.3% (n=1327) of TRACER participants had a total of 1579 adjudicated MIs during a median follow-up of 502 days (25th and 75th percentiles [IQR] 349-667). Of all MIs, 5.2% (n=82) were CEC-adjudicated type 2 MIs, occurring in 76 patients. The incidence of type 2 MI was higher in the first month following randomization, after which the distribution became more scattered. The most frequent potential provoking factors for type 2 MIs were tachyarrhythmias (38.2%), anemia/bleeding (21.1%), hypotension/shock (14.5%), and hypertensive emergencies (11.8%). Overall, 36.3% had a troponin increase >10× the upper limit of normal. Coronary angiography was performed in 22.4% (n=17) of patients during hospitalizations due to type 2 MIs. The hazard of cardiovascular death was numerically higher following type 2 MI (vs. no MI, adj. HR 11.82, 95% CI 5.71-24.46; P<.0001) than that of type 1 MI (vs. no MI, adj. HR 8.90, 95% CI 6.93-11.43; P<.0001). CONCLUSIONS: Type 2 MIs were more prevalent in the first month after ACS, were characterized by the presence of triggers and infrequent use of an invasive strategy, and were associated with a high risk of death. Further efforts are needed to better define the role and implications of type 2 MI in both clinical practice and research.

Secondary Prevention Therapies in Real-World Patients with Myocardial Infarction: Eligibility Based on Randomized Trials Supporting European and American Guidelines.

OBJECTIVE: We aimed to evaluate the applicability of the eligibility criteria of randomized controlled trials (RCTs) cited in guideline recommendations in a real-world cohort of patients receiving secondary prevention after acute myocardial infarction from the EPICOR registries. METHODS: Recommendations provided by American and European guidelines for acute myocardial infarction were classified into general (applying to all patients) and specific (applying to patients with left ventricular dysfunction or heart failure). Randomized controlled trials cited in these recommendations were selected, and their entry criteria were applied to our international cohort of 18,117 patients. RESULTS: There were 91.5% patients eligible for beta blockers (84.6% for general, and 5.9% for specific recommendations), 97.7% eligible for renin-angiotensin system inhibitor (angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers [ACEI/ARB]) recommendations (69.9% for general, 27.9% for specific) and 4.1% eligible for mineralocorticoid receptor antagonists (only specific recommendations). The percentages of patients with eligibility criteria who were discharged with a prescription of the recommended therapies were 80%-85% for beta blockers, 70%-75% for ACEI/ARB, and 29% for mineralocorticoid receptor antagonists. There were large regional variations in the percentage of eligible patients and in those receiving the medications (eg, 95% in Northern Europe and 57% in Southeast Asia for beta blockers). CONCLUSION: Most real-world acute myocardial infarction patients are eligible for secondary prevention therapy in both general and specific guideline recommendations, and the percentage of those on beta blockers and ACEI/ARB at hospital discharge is high. There are large regional variations in the proportion of patients receiving recommended therapies. Local targeted interventions are needed for quality improvement.

Dynamic modeling of 90-day mortality in ST-elevation myocardial infarction patients undergoing primary percutaneous coronary intervention.

AIMS: Dynamic risk models update the risk profile of ST-elevation myocardial infarction (STEMI) patients over the acute period following the event and have implications to clinical practice and research. METHODS AND RESULTS: Multivariable survival models were developed in 5,745 STEMI patients undergoing primary percutaneous coronary intervention (PCI) enrolled in the APEX-AMI trial to predict 90-day mortality from 4 clinically relevant times: baseline, 2 hours, 24 hours, and 96 hours. Culprit coronary thrombolysis in myocardial infarction flow grade, 30-minute post-PCI worst-lead ST-elevation residual, and in-hospital clinical events were considered in the models. The 90-day mortality was 4.7%; the cumulative proportion of mortality occurring within 2, 24, and 96 hours was 8%, 22%, and 40% respectively. Relative to the baseline risk factors, age and systolic blood pressure remained highly ranked in the post-baseline models. However, the relative importance of heart rate, Killip class, and creatinine declined, whereas markers of coronary reperfusion and in-hospital events (shock, congestive heart failure) became increasingly influential. The c-index increased from 0.819 at baseline to 0.847 at 96 hours. Over the forecasting periods, the proportion of "low-risk" (<1.1% 90-day mortality) patients increased from 20% to 49%. This approach derived from an unfolding series of models reveals the shifting levels of mortality risk from baseline to 96 hours. CONCLUSION: This novel approach in STEMI patients undergoing primary PCI demonstrates the dynamic nature of risk over time and may prove useful in understanding risk and in clinical decision making.

Long-Term Outcome of Acute Coronary Syndromes in Patients on Chronic Oral Anticoagulants: Data from the EPICOR Study.

OBJECTIVE: To analyze characteristics, management and outcomes of patients with acute coronary syndromes (ACS) receiving chronic oral anticoagulant (OAC) therapy enrolled in the EPICOR (long-tErm follow-uP of antithrombotic management patterns In acute CORonary syndrome patients) prospective, international, observational study of antithrombotic management patterns in ACS survivors (NCT01171404). METHODS: This post-hoc analysis evaluated the association between OAC use at baseline (OACb) and time from hospital admission to percutaneous coronary intervention (PCI) (tHA-PCI), pre-PCI thrombolysis in myocardial infarction (TIMI) 3 flow, stent type, length of hospitalization, and clinical endpoints; death, non-fatal MI, and non-fatal stroke, a composite of these ± bleeding, over 2 years' followup. RESULTS: Of 10,568 ACS patients, 345 (3.3%) were on OACb (non-ST-segment elevation ACS [NSTEACS], n=268; ST-segment elevation MI [STEMI], n=77). OACb patients were older with more comorbidities. In NSTE-ACS OACb patients, tHA-PCI was longer (median 57.4 vs. 27.8 h; p=.008), and TIMI 3 flow rarer (26.0 vs. 33.5%; p=0.035). OACb patients had longer mean hospital stay (NSTEACS: 8.9 vs. 7.6 days; p<0.001; STEMI: 9.5 vs. 7.8 days; p=0.015), and higher rates of the composite endpoint (NSTE-ACS: 16.8 vs. 8.8%; p<0.0001; STEMI: 23.4 vs. 5.9%; p<0.0001). Bleeding events were more common with OACb (NSTE-ACS: 6.0 vs. 3.3%; p=0.01; STEMI: 6.5 vs. 2.8%; p=0.04). CONCLUSION: At 2-years, OACb use was associated with an increased risk of cardiovascular and bleeding events in STEMI and NSTE-ACS. NSTE-ACS patients on OACb experienced prolonged time to intervention, lower rates of TIMI 3 flow and longer hospitalization.