ST elevation myocardial infarction recurrent ischemia/infarction

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Overview
Reinfarction is defined as a recurrence of a myocardial infarction. The rate of reinfarction on angiography (15-20% following fibrinolytic administration) is higher than the clinical rate of reinfarction (2% to 6%) in the setting of ST elevation myocardial infarction.

Clinical predictors and timing of reinfarction following fibrinolytic administration
The frequency, timing, and clinical predictors of in-hospital reinfarction were evaluated in the Global Utilization of Streptokinase and Tissue plasminogen activator (alteplase) for Occluded coronary arteries (GUSTO I) and Global Use of Strategies To Open occluded coronary arteries (GUSTO III) populations. Reinfarction developed in in 2,258 out of 55, 911 patients (4.3%). Reinfarction was diagnosed a median of 3.8 days after fibrinolytic administration. The specific fibrinolytic agent administered was not associated with the rate of reinfarction: streptokinase, 4.1%; alteplase, 4.3%; reteplase, 4.5%; combined streptokinase and alteplase, 4.4%; P=0.55. Multivariate predictors or reinfarction included the following: older age, shorter time to fibrinolytic administration, non-US enrollment, nonsmoking status, prior MI or angina, female gender, anterior MI, and lower systolic blood pressure.

Angiographic predictors of reinfarction following fibrinolytic administration
Gibson et al documented that angiographically confirmed reocclusion is observed more frequently among culprit arteries with TIMI grade 2 versus TIMI grade 3 flow (10.4% vs. 2.2%, p = 0.003), in ulcerated lesions (10.7% vs. 3.0%, p = 0.009) and in the presence of collateral vessels (18.2% vs. 5.6%, p = 0.03). Trends toward higher rates of reocclusion were observed among eccentric (7.3% vs. 2.3%, p = 0.06) and thrombotic (8.4% vs. 3.3%, p = 0.06) lesions. Reocclusion was associated with a more severe percent diameter stenosis on quantitative coronary angiography (77.9% vs. 73.9%, p = 0.04). . Pulsatile flow or reversal of flow during systole has been associated with a higher rate of reinfarction.

Prognosis of reinfarction following fibrinolytic administration
In the combined GUSTO I and III experience, reinfarction was associated with a higher mortality at 30 days(11.3% versus 3.5% without reinfarction; odds ratio, 3.5; P<0.001) and from 30 days to 1 year (4.7% versus 3.2%; hazard ratio, 1.5; P<0.001). Significant multivariate predictors of in-hospital death or reinfarction included older age, higher Killip class, lower systolic and diastolic blood pressures, higher heart rate, the presence of an anterior MI, smoking, a history of prior MI, gender, and country of enrollment (all P<0.001). In contrast, Gibson et al did not find an increase in mortality between 30 days and 2 years in over 20,000 patients in the TIMI trials. Higher mortality at 2 years was found to be due to an early divergence in mortality by 30 days and was not due to a significant increase in late mortality between 30 days and 2 years (4.38% [31/707] vs. 3.76% [685/18,206], p = NS).

Strategies to reduce reinfarction following fibrinolytic administration
Gibson et al reported in their analysis of over 20,000 patients from the TIMI trials that percutaneous coronary intervention performed at the time of the index hospitalization was associated with a lower rate of in-hospital recurrent MI (1.6% vs. 4.5%, p < 0.001) and lower two-year mortality (5.6% vs. 11.6%, p < 0.001). Likewise, coronary artery bypass graft (CABG) surgery was also associated with a lower rate of recurrent MI (0.7% vs. 4.3%, p < 0.001) as well as a lower two-year mortality rate (7.95% vs. 10.6%, p = 0.0008).

==ACC/AHA Guidelines (DO NOT EDIT) ==

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Class I
1. Patients with recurrent ischemic-type chest discomfort after initial reperfusion therapy for STEMI should undergo escalation of medical therapy with nitrates and beta-blockers to decrease myocardial oxygen demand and reduce ischemia. Intravenous anticoagulation should be initiated if not already accomplished. (Level of Evidence: B)

2. In addition to escalation of medical therapy, patients with recurrent ischemic-type chest discomfort and signs of hemodynamic instability, poor LV function, or a large area of myocardium at risk should be referred urgently for cardiac catheterization and undergo revascularization as needed. Insertion of an IABP should also be considered. (Level of Evidence: C)

3. Patients with recurrent ischemic-type chest discomfort who are considered candidates for revascularization should undergo coronary arteriography and PCI or CABG as dictated by coronary anatomy. (Level of Evidence: B)

Class IIa
1. It is reasonable to (re)administer fibrinolytic therapy to patients with recurrent ST elevation and ischemictype chest discomfort who are not considered candidates for revascularization or for whom coronary angiography and PCI cannot be rapidly (ideally less than 60 minutes from the onset of recurrent discomfort) implemented. (Level of Evidence: C)

Class III
1. Streptokinase should not be readministered to treat recurrent ischemia/infarction in patients who received a non–fibrin-specific fibrinolytic agent more than 5 days previously to treat the acute STEMI event. (Level of Evidence: C) }}