For more than a decade, there's been uncertainty regarding whether post–cardiac arrest patients should be sent for immediate coronary angiography or not. The 2013 American College of Cardiology and the American Heart Association joint update of the guidelines for management of ST-segment elevation myocardial infarction (STEMI) provided guidance and stated that patients with ST-segment elevation (STE) on the ECG were best managed with immediate coronary angiography and evaluation for percutaneous coronary intervention (PCI).
Currently, STE remains the most reliable marker of an underlying acute coronary culprit lesion. However, controversy persisted regarding optimal management of patients who lacked post-arrest STE on ECG. In 2015, Rab and colleagues, representing the Interventional Council of the American College of Cardiology, evaluated the literature on post-arrest coronary angiography and provided further guidance, suggesting that many of these patients without STE would still benefit from immediate angiography and possible PCI. This recommendation, however, was largely based on observational studies.
In 2019, Lemkes and colleagues published the COACT trial. This was the first large randomized trial of post–cardiac arrest patients without STE whose cause of arrest was not obviously noncardiac. Patients were separated into groups receiving either immediate coronary angiography (average time from randomization to catheterization, 0.8 hours) or delayed coronary angiography after neurologic recovery (average time from randomization to angiography, 119.9 hours). The authors found no that there was no survival or neurologic benefit to immediate angiography.
Confusion increased after publication of the COACT trial regarding optimal care of post–cardiac arrest patients without STE. In patients who do not have STE or an obvious noncardiac cause of arrest, should they receive emergent coronary angiography or is it better to initially admit them for stabilization and perform angiography later during the hospital course if they remains alive? Should the results of the COACT trial overturn the results of many prior observational studies and the recommendations of the study by Rab and colleagues and the Interventional Council of the American College of Cardiology? Was the COACT trial just an outlier? In recent months, two more key randomized trials have been published that should settle the confusion regarding optimal care of these patients.
The TOMAHAWK trial, published in December 2021, was a multicenter trial in which 554 patients with out-of-hospital cardiac arrest who were successfully resuscitated were randomized to undergo either immediate coronary angiography or initial intensive care assessment with delayed or selective angiography.
The patients in this trial included those with initial shockable as well as nonshockable rhythms. The median time from arrest to angiography was 2.9 hours in the immediate-angiography group and 46.9 hours in the delayed-angiography group. The frequency of PCI was 39.6% in the immediate-angiography group and 43.2% in the delayed-angiography group. Only 40% of patients overall were found to have a culprit lesion that was deemed responsible for the arrest. The researchers found no benefit to early angiography vs delayed angiography in terms of 30-day survival or neurologic outcome.
The EMERGE trial, published in June 2022, is the third key randomized trial comparing emergency vs delayed coronary angiography in survivors of out-of-hospital cardiac arrest. In this study, 279 patients were randomized, including those with initially shockable and nonshockable rhythms. Patients receiving emergency angiography underwent the procedure after an average of only 2 hours, with 30% receiving PCI; in contrast, those receiving delayed angiography did so after an average of 65.5 hours, with 23% receiving PCI.
The researchers found no significant benefit of early angiography compared with delayed angiography in terms of 180-day survival with good neurologic outcome or in terms of overall survival. The researchers admit that the study was underpowered; because of a loss of funding, they were unable to enroll their desired number of patients for randomization. Nevertheless, the results are in line with the prior randomized clinical trials.
To wrap up, the publication by Rab and colleagues was largely based on observational studies that suggested that a large percentage of non-STE post-arrest patients had culprit coronary lesions that would be amenable to PCI, and therefore we presumed that those patients would have a better outcome with emergent revascularization.
The recent randomized studies, however, have demonstrated that only a minority of patients have acute culprit lesions, and therefore only a minority of patients will benefit from emergent revascularization.
On the other hand, when patients without culprit lesions are routinely sent for what turns out to be unnecessary emergent angiography, vital time is lost in performing critical resuscitative care. In addition, these patients become at-risk for procedural complications. It should be expected that these patients will be at risk for a worse outcome.
Although STE remains the most reliable marker of an acute culprit lesion, we know that some patients without STE have culprit lesions as well. Ongoing and future research must seek to identify other clinical or ECG findings that can reliably predict the presence of these lesions so that the appropriate patients without STE can be identified for emergent catheterization. Proposed markers might include specific arrest rhythms, clinical history, non–ST-related ECG findings, point-of-care echocardiographic findings, and troponin values.
Until those markers are properly identified in randomized studies, the best evidence we now have is that post–cardiac arrest patients who lack STE are unlikely to benefit from emergent coronary angiography.
Amal Mattu, MD, is a professor, vice chair of education, and co-director of the emergency cardiology fellowship in the Department of Emergency Medicine at the University of Maryland School of Medicine in Baltimore.
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Cite this: Amal Mattu. Post-Arrest Angiography for Patients Without STE? - Medscape - Aug 04, 2022.