Patients successfully resuscitated after an out-of-hospital cardiac arrest who did not have ST-segment elevation on their electrocardiogram did not benefit from emergency coronary angiography in a new randomized clinical trial.
In the EMERGE trial, a strategy of emergency coronary angiography was not found to be better than a strategy of delayed coronary angiography with respect to the 180-day survival rate with no or minimal neurologic sequelae.
The authors note that, although the study was underpowered, the results are consistent with previously published studies and do not support routine emergency coronary angiography in survivors of out-of-hospital cardiac arrest without ST elevation.
But senior author, Christian Spaulding, MD, PhD, European Hospital Georges Pompidou, Paris, France, believes some such patients may still benefit from emergency angiography.
“Most patients who have been resuscitated after out of hospital cardiac arrest will have neurological damage which will be the primary cause of death,” Spaulding told theheart.org | Medscape Cardiology. “It will not make any difference to these patients if they have a coronary lesion treated. So, going forward, I think we need to look for patients who are likely not to have a high degree of neurological damage and who could still benefit from early angiography.”
The EMERGE study was published online in JAMA Cardiology on June 8.
In patients who have suffered an out-of-hospital cardiac arrest with no obvious noncardiac cause such as trauma, it is believed that the cardiac arrest is caused by coronary occlusions, and emergency angiography may be able to improve survival in these patients, Spaulding explained.
In about one third of such patients, the ECG before hospitalization shows ST elevation and, in this group, there is a high probability (around 70% to 80%) that there is going to be a coronary occlusion, so these patients are usually taken directly to emergency angiography.
But, in the other two thirds of patients, there is no ST elevation on the ECG, and in these patients the chances of finding a coronary occlusion are lower (around 25% to 35%).
The EMERGE trial was conducted in this latter group without ST elevation.
For the study, which was conducted in 22 French centers, 279 such patients (mean age, 64 years) were randomized to either emergency or delayed (48 to 96 hours) coronary angiography. The mean time delay between randomization and coronary angiography was 0.6 hours in the emergency group and 55.1 hours in the delayed group.
The primary outcome was the 180-day survival rate with minimal neurological damage, defined as Cerebral Performance Category of 2 or less. This occurred in 34.1% of the emergency angiography group and 30.7% of the delayed angiography group (hazard ratio [HR], 0.87; 95% confidence interval [CI], 0.65 – 1.15; P = .32).
There was also no difference in the overall survival rate at 180 days (36.2% versus 33.3%; HR, 0.86; P = .31) and in secondary outcomes between the two groups.
Spaulding noted that three other randomized trials in a similar patient population have all shown similar results, with no difference in survival found between patients who have emergency coronary angiography as soon as they are admitted to hospital and those in whom angiography was not performed until a couple of days later.
However, several registry studies in a total of more than 6000 patients have suggested a benefit of immediate angiography in these patients. “So, there is some disconnect here,” he said.
Spaulding believes the reason for this disconnect may be that the registry studies may have included patients with less neurological damage, so more likely to survive and to benefit from having coronary lesions treated promptly.
“Paramedics sometimes make a judgment on which patients may have minimal neurological damage and this may affect the choice of hospital a patient is taken to, and then the emergency department doctor may again assess whether a patient should go for immediate angiography or not. So, patients in these registry studies who received emergency angiography were likely already preselected to some extent,” he suggested.
In contrast, the randomized trials have accepted all patients, so there were probably more with neurological damage. “In our trial, almost 70% of patients were in asystole. These are the ones who [are] the most likely to have neurological damage,” he pointed out.
“Because there was such a striking difference in the registry studies, I think there is a group of patients [who] will benefit from immediate emergency coronary angiography, but we have to work out how to select these patients,” he commented.
Spaulding noted that a recent registry study published in JACC: Cardiovascular Interventions used a score known as MIRACLE2 (which takes into account various factors including age of patient and type of rhythm on ECG) and the degree of cardiogenic shock on arrival at hospital as measured by the SCAI shock score to define a potential cohort of patients at low risk for neurologic injury who benefit most from immediate coronary angiography.
“In my practice at present, I would advise the emergency team that a young patient who had had resuscitation started quickly, had been defibrillated early and got to hospital quickly should go for an immediate coronary angiogram. It can’t do any harm and there may be a benefit in such patients,” Spaulding added.
JAMA Card. Published online June 8. Full text.
The EMERGE study was supported in part by Assistance Publique–Hôpitaux de Paris and the French Ministry of Health, through the national Programme Hospitalier de Recherche Clinique. Spaulding reports no relevant financial relationships.