Early intervention key to heart attack care, study says

February 8, 2013 – Manesh Patel, MD, and others studied patient data from the APEX-AMI trial to determine the prevalence of abortive heart attacks.

More than 10 percent of patients undergoing percutaneous coronary intervention (PCI) for an ST-segment elevation myocardial infarction (STEMI) experienced an aborted heart attack, according to a new study by DCRI researchers.

The study, by Manesh Patel, MD; Christopher Granger, MD; and others, appears in the February 2013 issue of the American Heart Journal.

A STEMI is a type of heart attack in which the coronary artery becomes completely obstructed. If STEMI patients are treated early enough to restore blood flow and prevent the death of cardiac tissue, the heart attack is said to be an aborted myocardial infarction (AbMI). Although early intervention has long been a primary tenet of heart attack treatment, the prevalence of AbMIs and their relationship to certain cardiac markers have not been well understood.

To obtain a better picture of AbMIs in STEMI patients, the researchers examined patient data from the Assessment of Pexelizumab in Acute Myocardial Infarction (APEX-AMI) trial. That study compared the drug pexelizumab to a placebo in 5,745 patients with high-risk STEMI who underwent primary PCI between 2004 and 2006. APEX-AMI also included a cardiac magnetic resonance (CMR) substudy that measured the size of the infarct, or damaged heart tissue, in the same patients.

For the current study, Patel, Granger, and their colleagues analyzed electrocardiograms, angiograms, and CMR images. Of the 5,745 patients enrolled in APEX-AMI, 372 did not undergo primary PCI, and 791 did not have relevant data available. Of the remaining patients, those with documented reinfarction (141) and those with late-peaking biomarkers (471) were excluded. Of the 3,970 patients evaluated, 437 (11 percent) were identified as having AbMI, including 14 (19 percent) of 73 patients undergoing CMR.

Patients with AbMI were generally older, more often female, and of lower body weight. However, other cardiovascular risk factors were similar between groups. Patients with AbMI had shorter times from symptom onset to presentation, higher rates of blood flow prior to PCI, and higher rates of complete ST-segment resolution following PCI. As the researchers expected, patients with AbMI had improved outcomes.

The researchers concluded that the death of cardiac tissue can be avoided entirely for STEMI patients who receive rapid and complete reperfusion. The data from the CMR substudy also suggest that AbMI can be better categorized and measured in future heart studies. This would allow other researchers to better quantify the amount of damage done to cardiac tissue during a heart attack.