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Timely catheterization with percutaneous coronary intervention (PCI), if needed, can improve in-hospital survival in unconscious patients resuscitated after nontraumatic cardiac arrest. The invasive strategy appears to benefit even those without ST-segment elevation, suggest the authors of a retrospective study published online September 9, 2012, ahead of print in the American Journal of Cardiology.

Investigators led by Gaetano Nucifora, MD, of University Hospital Santa Maria della Misericordia (Udine, Italy), looked at the management and outcomes of 93 patients who were admitted to their intensive care unit in an unconscious state after resuscitation. All had recovered spontaneous circulation following cardiac arrest (with no obvious noncardiac cause) outside the hospital. 

CAD, Culprit Lesion More Common in ST Elevation Patients

Angiography was performed in 66 patients (71%), the majority (n = 48) of whom were emergent cases. Overall, significant CAD was found in 86%, although it was more common in those with ST-segment elevation than those with other ECG patterns (96% vs. 79%). Similarly, an acute or recent culprit lesion was identified in a higher proportion of ST-segment elevation patients (79% vs. 42%).

The prevalence of culprit lesions did not differ between patients with ventricular fibrillation/tachycardia and those with pulseless electrical activity/asystole as the initial arrest rhythm (P = 0.38).

In patients referred for emergent angiography, successful PCI of a culprit lesion was performed in 25 patients (52%), whereas in those referred for delayed angiography, successful PCI of a presumed culprit lesion was accomplished in 6 patients (33%).

Overall, 54% of patients survived to hospital discharge. Survival rates were 60% in the emergent group vs. 47% in the delayed/no angiography group. In the entire cohort, a favorable neurologic outcome, as indicated by Cerebral Performance Categories scores of 1 or 2, was achieved in 72%. On average, patients who underwent emergency angiography spent 20 fewer days in the hospital than their counterparts who received deferred or no angiography (median 18 days vs. median 38 days; P = 0.018). 

On multivariate analysis, in the overall study population, age greater than 60 years was associated with lower in-hospital survival, while emergent angiography and successful emergent PCI were linked to improved survival (table 1).

Table 1. Independent Correlates of In-hospital Survival in the Overall Cohort

Specifically among patients referred for angiography, age greater than 60 years and delayed angiography were both associated with reduced survival (table 2).

Table 2. Independent Correlates of In-hospital Survival in Patients Referred for Angiography

According to the authors, the study suggests that ECG findings “should not be considered a strict selection criterion for performing emergency coronary angiography in resuscitated patients with [out-of-hospital cardiac arrest] without obvious extracardiac cause; even in the absence of ST-segment elevation on post-[resuscitation ECG], acute culprit coronary lesions may indeed be present and considered the trigger of cardiac arrest.”

The prognostic value of an invasive strategy “has been consistently demonstrated by previous studies including conscious and comatose patients after [recovery of spontaneous circulation],” Dr. Nucifora and colleagues write. Moreover, the positive impact on survival is probably due to the timely identification and treatment of ACS, they add. 

In addition, the finding suggests that an invasive strategy may be cost-effective because it not only improves survival but also shortens hospital stay, the authors observe. However, further studies are needed to confirm this single-center observation.

Uncertainty Centers on Patients Without ST Elevation

In a telephone interview with TCTMD, Jeffrey W. Moses, MD, of Columbia University Medical Center/Weill Cornell Medical Center (New York, NY), pointed out that conspicuously missing in the paper is discussion of whether any patients received therapeutic hypothermia. Evidence now supports its routine use in all patients, he noted.

With regard to the core question of which patients should receive angiography, Dr. Moses said that those with ST-segment elevation “have a very high yield of occlusive arterial disease,” and in fact an early invasive strategy is recommended for such patients in the American Heart Association guidelines and a consensus statement on cardiopulmonary resuscitation.

However, he added, several studies suggest that patients without ST-segment elevation should not be excluded. “The question is, where in the yield curve [for occlusive or acute lesions] is it worth it to start bringing everyone to the cath lab?” Dr. Moses said. “You can make an argument for including non-ST elevation patients.”

As yet, he conceded “there aren’t good clues as to who is going to have an occlusion—with the exception of STEMI [patients]. This is still an area under intense investigation.”

The approach to non-STEMI patients in US hospitals is “pretty varied,” Dr. Moses added. “My personal feeling is, until you know better, give patients the benefit of the doubt—take them to the cath lab, because the survival yields are not bad.” 

Selection Bias Clouds Results

In a telephone interview, Thomas D. Stuckey, MD, of the LeBauer Cardiovascular Research Foundation (Greensboro, NC), told TCTMD that the paper “is suggestive that coronary angiography should be used liberally and often” in out-of-hospital cardiac-arrest patients. But the presence of “a massive selection bias” is a major limitation of the study that renders its results only hypothesis-generating, he stressed. “The patients who didn’t get angiography were selected not to get angiography,” he observed, adding, “If they had detailed the reasons why it was withheld, they would have made a stronger case.”

Dr. Stuckey cited age, comorbidities, and poor functional status before the cardiac arrest as factors that might prompt a decision to forgo catheterization. “There are many reasons not to take people to the cath lab,” he said, “so the people who did go were perceived to be likely to benefit.

“I think the likelihood of the benefit of reperfusion is suggested by the findings,” he concluded, but they have to be interpreted with caution. Dr. Stuckey said he believes most major centers are “fairly aggressive” in performing angiography on most patients. “I support the paper in that regard,” he said. “I just think that the statistics are a little clouded from the standpoint that there’s a tremendous built-in selection bias.”

Study Details

Mean age was 67 ± 12 years, and 71% of the patients were men. Those with proven CAD were more likely to have dyslipidemia and to have experienced symptoms prior to cardiac arrest.

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