By Michael H. Crawford, MD, Editor

SYNOPSIS: An analysis of the COACT trial for one-year outcomes continues to confirm the original 90-day outcomes, namely that there is no difference in mortality or morbidity in the immediate vs. the delayed coronary intervention groups of patients who are successfully resuscitated after cardiac arrest and do not show evidence of STEMI or cardiogenic shock.

SOURCE: Lemkes JS, Janssens GS, van der Hoeven NW, et al. Coronary angiography after cardiac arrest without ST segment elevation: One-year outcomes of the COACT Randomized Clinical Trial. JAMA Cardiol 2020; Sept. 2. doi: 10.1001/jamacardio.2020.3670. [Online ahead of print].

Immediate coronary angiography and percutaneous intervention in appropriate patients is the standard of care for resuscitated cardiac arrest patients with evidence of ST elevation myocardial infarction (STEMI). However, the treatment of non-STEMI patients is controversial since the Coronary Angiography After Cardiac Arrest (COACT) trial of such patients failed to show reduced mortality at 90 days. Since it is possible there would be long-term benefits of an invasive approach, the investigators from the COACT trial analyzed the one-year follow-up data.

COACT was a multicenter, randomized, open-label study of immediate vs. delayed (until neurologic recovery) coronary intervention in successfully resuscitated (but unconscious) patients without ECG evidence of STEMI. Patients were excluded if they had cardiogenic shock, severe renal dysfunction, or had an obvious non-cardiac cause of arrest. Immediate coronary interventions were initiated within two hours. In most patients with delayed intervention, such interventions occurred after discharge from the ICU. All patients underwent temperature management and other guideline-directed therapy.

Investigators acquired one-year follow-up data by phone calls to the patient, family, or primary physician and through an examination of medical records and death registries. The primary endpoints were death, myocardial infarction since the index hospitalization, repeated revascularization since the index hospitalization, hospitalization for heart failure, and implantable cardioverter-defibrillator (ICD) shock.

At 90 days, there were 538 patients. At one year, there were 522 patients because of attrition of consent for the one-year follow-up (264 in the immediate group, 258 in the delayed group). In total, 79% were men, with a mean age of 65 years. Coronary intervention was performed in 97% of the immediate group at a median time of one hour. Such interventions were performed in 65% of the delayed group at a median time of 120 hours.

An acute thrombotic occlusion was found in < 10% of patients (3% immediate group, 8% delayed group). In about one-third of both groups, a chronic total occlusion was found, and about one-third exhibited no significant coronary artery lesions. Percutaneous coronary interventions were performed in about one-third of the immediate group and one-quarter of the delayed group. Fewer than 10% underwent coronary bypass surgery (6% and 8%, respectively).

One-year survival was 61% in the immediate group and 64% in the delayed group (odds ratio [OR], 0.90; 95% confidence interval [CI], 0.63-1.28). The composite endpoint of death, myocardial infarction, or repeat revascularization since the index hospitalization was 43% in the immediate group and 41% in the delayed group (OR, 1.10; 95% CI, 0.77-1.56). Researchers did not observe any significant differences between the groups for any other outcomes at one year.

The authors concluded that since there were no significant differences in outcomes at 90 days or one year, coronary interventions in successfully resuscitated cardiac arrest patients without evidence of STEMI or cardiogenic shock can be delayed until neurologic recovery is evident.

COMMENTARY

Although this study was powered only for the 90-day endpoint and the results are technically hypothesis-generating, I believe it will finally put this debate to rest. Also, the results are consistent with the many other studies of an early invasive vs. a selective delayed invasive approach for non-STEMI. In non-STEMI, an immediate invasive approach is not necessary unless there are other indications, such as cardiogenic shock.

Despite the negative results, there are several interesting findings in this study. Unlike the more general management studies of non-STEMI, in this study of cardiac arrest survivors, one-third showed no significant coronary artery lesions while one-third exhibited chronic total occlusions. Among the remaining one-third, the authors found thrombotic coronary artery occlusions in only 5% of the total study population.

Even though this was a randomized, controlled, multicenter trial, there were some weaknesses. It was powered for the 90-day mortality outcome, and almost all the mortality occurred in the first 90 days. From day 90 to day 365, the mortality rate was 2%, and the rates of all the other outcomes explored also were low. Thus, it could be said this study was underpowered to find any differences in one-year outcomes. Further, this study was not blinded, but that would have been difficult. However, the core lab that looked at all the data was blinded. In addition, there are no data on medical therapy during follow-up.

Despite these weaknesses, I believe this study is quite compelling and supports a selective and delayed approach to coronary interventions in unconscious cardiac arrest survivors without ECG evidence of STEMI. The first selection criterion should be cardiogenic shock. After that, neurologic recovery.