No Gains From Early Angiography After Cardiac Arrest Without STEMI

A speedy trip to the cath lab for coronary angiography is not linked to better outcomes in patients who suffer an out-of-hospital cardiac arrest but do not have ST-segment elevation on an initial ECG, a meta-analysis shows.

In pooled results from 11 studies, there were no differences in 30-day mortality, the likelihood of good neurological status, or the rate of PCI based on whether patients underwent early or nonearly angiography, according to the analysis published in the October 12, 2020, issue of JACC: Cardiovascular Interventions. Comorbidities, and not revascularization, appeared to have a greater impact on 30-day mortality.

Based on the results, “routine early coronary angiography cannot be recommended in this population,” the researchers conclude. The meta-analysis “shows that patient-related clinical and presentation factors, including diabetes mellitus, chronic renal failure, previous PCI, and lactate level, predict mortality more than the procedure itself,” they say. “Further studies are needed to better determine the selection criteria and identify those patients who will benefit most.”

Whether to take a patient with cardiac arrest and no ST-segment elevation to the cath lab is a common question with no clear answer, senior author Samir Kapadia, MD (Cleveland Clinic, OH), told TCTMD. “This is a complex decision. It’s not a cookbook thing.”

There are no straightforward guidelines for this, “so many times people want to do things because they feel that the onus is on them to decide whether something should be done or not and they don’t want to miss anything. That is the concept” behind taking patients for angiography, Kapadia explained. “But I think it has to be a thoughtful approach. It is not automatic that everybody that has a cardiac arrest should go to the cath lab . . . . Whether it hurts or not is questionable, but at least it does not help. And a multilayered approach of having different teams engaged in the decision-making is critical.”

Addressing Uncertainty

Although an early invasive strategy is recommended in patients with an out-of-hospital cardiac arrest and STEMI based on demonstrated benefit in reducing mortality, the impact of such a strategy in patients without ST-segment elevation is less clear—prior studies have provided mixed results.

This is a complex decision. It’s not a cookbook thing. Samir Kapadia

Last year, results of the COACT trial showed that immediate angiography did not improve 90-day survival compared with a delayed approach. One-year follow-up yielded similar findings. As Michael Mooney, MD (Minneapolis Cardiology Associates, MN), notes in an editorial accompanying this new meta-analysis, however, the confidence interval in COACT could not rule out either a 38% harm or a 27% benefit of immediate angiography in terms of survival.

To get a better handle on the issue, Kapadia and colleagues, with lead author Beni Verma, MD (Cleveland Clinic), pooled results of 11 observational and randomized studies, including COACT, with a total of 3,581 patients who had suffered an out-of-hospital cardiac arrest and did not have ST-segment elevation on ECG.

Early angiography was variably defined across studies: it was within 2 hours in five studies, within 6 hours in two studies, within 12 hours in one study, and within 24 hours in two studies. Another defined it as direct delivery of the patient to the cath lab. Overall, 42% underwent early angiography.

The primary outcome of the meta-analysis was 30-day mortality, and there was no difference between the early and nonearly angiography groups (RR 0.86; 95% CI 0.71-1.04); a sensitivity analysis showed a similar finding when the COACT data were excluded.

There also were no differences between groups in terms of the proportion of patients with good neurological status at 30 days or discharge (RR 1.08; 95% CI 0.94-1.24) or the rate of PCI among those who underwent angiography (RR 1.22; 95% CI 0.94-1.59). Moreover, the proportion of patients who received the hypothermia protocol, had an unwitnessed cardiac arrest, and had a shockable rhythm was similar in both groups. There was no difference in the time to return of spontaneous circulation, but the time to target temperature was 66 minutes shorter in the nonearly angiography group.

The ACE Protocol

In his editorial, Mooney says the meta-analysis “adds to and affirms a series of recent reports that conclude early coronary angiography should not be mandated when compared to delayed or nonearly coronary angiography.”

He points out that another meta-analysis published last year showed that angiography—either early or delayed—was associated with lower long-term mortality compared with no angiography. “This as a conclusion is importantly confounded by clinical futility because those dying a neurological death are not commonly sent for angiography,” Mooney writes. “As such, in a nonrandomized cohort, this can make angiography appear to be associated with improved survival.”

Kapadia, too, pointed out the potential for survivor bias in an analysis like that one, adding that clinicians are often choosing between an early or delayed strategy with little guidance.

There are several ongoing trials looking into the issue, but in the meantime, how can clinicians make that decision? “Systems of care to standardize early triage and treatment are emerging but not fully adopted nationally,” Mooney writes. “And furthermore, postarrest in-hospital care and subsequent optimal rehabilitation pathways are lacking. As a result, variability in regional and hospital survival rates remains unacceptably large.”

To provide structure to the decision-making process in this scenario, the Cleveland Clinic uses the ACE (Assess, Consult, Expectations) protocol, described in the central illustration of the paper. First, physicians consider a list of factors that increase the risk of poor outcomes even if revascularization is performed; this includes things like ongoing CPR, age over 85, and unwitnessed arrest. They then assess cardiac and noncardiac status before consulting with an interventional cardiologist, the cardiac ICU team, and the family to decide on management. And finally, they evaluate expectations for the various treatment options, including therapeutic hypothermia and possibly mechanical support.

Mooney says “proven strategies” like the ACE protocol “can serve as a template to organize complex multidisciplinary in-hospital care.” In addition, he says, “tools for predicting cardiac arrest hospital prognosis and neurological recovery such as the CAHP (Cardiac Arrest Hospital Prognosis) score can be very helpful and easily calculated, and perhaps adding an element of predictability in a clinically uncertain time.”

Additionally, he notes that authors of a recent statement on sudden cardiac arrest survivorship from the American Heart Association “set out a framework for developing an approach to meaningful recovery. The timing of angiography is only a small part of defining optimal post-cardiac arrest care, but an important one.”