When patients are comatose after an out-of-hospital cardiac arrest, should they be rushed into coronary angiography if echocardiography doesn’t show ST-segment elevation myocardial infarction (STEMI)? The first large randomized study of the question says no.

The trial, known as COACT, found that the overall survival rate at 90 days was 64.5 percent for 273 unconscious patients with return of spontaneous circulation after cardiac arrest, without STEMI, who received angiography within two or three hours versus 67.2 percent for 265 patients whose angiography was delayed for a median of nearly five days to allow for neurologic recovery (P=0.51).

“These results suggest that coronary angiography does not have to be performed immediately in patients who have had cardiac arrest without STEMI,” said Dr. Benjamin Abella and Dr. David Gaieski in an online editorial from the New England Journal of Medicine, where the study is published.

The findings were also released at the American College of Cardiology’s 2019 Scientific Sessions in New Orleans.

“This is a population where a lot of physicians don’t really know what to do. Should we go to the cath lab or should we take the patient to the ICU and focus on neurologic recovery?” chief author Dr. Jorrit Lemkes, an interventional cardiologist at Amsterdam University Medical Center, told Reuters Health in a telephone interview.

“The previous data were all observational, which has the potential for all sorts of bias,” he said.

Dr. Lemkes said about 15 to 20 percent of the patients were found to have unstable coronary lesions once they made it into the cath lab. Almost two-thirds had coronary artery disease. Approximately one third had a total chronic occlusion of one of the coronary arteries.

An intervention was performed in fewer than 40 percent of patients.

“Thus, only a small fraction of the trial population would be affected by the timing of coronary angiography – or the performance of coronary angiography at all. Therefore, the results of the trial should be interpreted with caution,” said Dr. Abella of the University of Pennsylvania’s Perelman School of Medicine and Dr. Gaieski of Jefferson Medical College in Philadelphia.

They said the subgroup age 70 and older and known to have a history of heart disease seemed to benefit from quick angiography. In addition, the study didn’t take into account whether people reported chest pain before collapsing.

But Dr. Lemke said that misses the point of the trial.

“The suggestion to only perform this type of research in patients who complain of chest pain makes it a little bit more difficult because, first of all, these patients are unconscious when they arrive at the hospital so it’s difficult to determine the patients who complain about chest pain,” he said. “The other thing is, ventricular tachycardia itself can cause chest discomfort and chest pain, so I’m not confident chest pain is a real predictor of acute thrombotic stenosis in these patients.”

Patients in the immediate and delayed angiography groups showed similar rates of the secondary endpoints such as survival until hospital discharge, neurologic status at ICU discharge, myocardial injury, need for renal-replacement therapy or duration of mechanical ventilation.

However, immediate angiography significantly delayed median time to target temperature. It was 5.4 hours in the immediate group and 4.7 hours in the delayed group, a 19 percent increase.

“We’re not sure how serious that is,” said Dr. Lemke, “but it’s something to consider.”

While 62.9 percent of patients in the immediate angiography group survived with good cerebral performance, mild disability or moderate disability, the rate was 64.4 percent in the delayed group, a non-significant difference.

The study was done at 19 medical centers in the Netherlands.