A simple tool to predict neurological outcomes for sufferers of out-of-hospital cardiac arrest (OHCA) could help clinicians determine when invasive coronary management is futile, a study in JACC: Cardiovascular Interventions suggests.
Using a registry from Paris and the surrounding suburbs, Wulfran Bougouin, MD, PhD, and colleagues retrospectively categorized 1,410 patients into low-risk, medium-risk and high-risk subgroups based on the Cardiac Arrest Hospital Prognosis (CAHP) score. The score includes age, public versus home setting, shockable or non-shockable rhythm, time from collapse to basic life support, time from life support to return of spontaneous circulation, pH and epinephrine dose.
Patients deemed at low-risk according to the CAHP score were 2.3 times more likely to survive to hospital discharge following early invasive management, defined as a coronary angiogram and (if indicated) PCI. But there was no significant survival benefit for medium- or high-risk patients, the authors found.
“The CAHP score could be a simple, immediately available tool to help triage OHCA patients for early invasive strategy, along with the medical history, ECG changes, and the first recorded rhythm,” Bougouin and colleagues wrote. “Patients with ST-segment elevation and assumed favorable prognosis seem best candidates for early invasive strategy, whereas performing CAG (coronary angiography) in patients without electrocardiographic sign of ongoing myocardial infarction and very high probability of irreversible neurological damage seems questionable.”
The authors pointed out patients with severe neurological damage may die regardless of their coronary function, and limiting angiography and PCI to patients who are more likely to benefit could cut wasteful healthcare spending.
Early angiography was performed in 86 percent of low-risk patients, 66 percent of medium-risk patients and 47 percent of high-risk individuals. Bougouin et al. said this could mean clinicians are already factoring presumed prognosis into clinical decision-making, but a large proportion of high-risk patients still received invasive management. Only 3 percent of them survived to discharge.
“Our results suggest that a simple prognostication score may permit avoiding unnecessary procedures in patients with minimal chances of survival, but also reinforce the association between CAG and outcome in patients with a preserved neurological outcome,” the researchers wrote.
The CAHP score requires external validation before being applied to other populations, the authors cautioned. In addition, the low survival rate in the high-risk subgroup (7 of 274 patients) could lead to a lack of statistical power in evaluating invasive management’s effect on survival.
In an accompanying editorial, Michael Ragosta, MD, described the study as a “valuable step” in helping determine which patients may actually benefit from cardiac treatment. It could also provide insights on whether to treat the heart or brain first following OHCA—a common conundrum. The usual brain treatment involves cooling body temperature to 32-34 degrees Celsius as soon as possible, Ragosta noted, but targeted temperature management may be delayed by angiography or PCI.
“As physicians, we always want to give patients the benefit of the doubt; however, emergency angiography saps valuable resources and shifts the focus from their brain to their heart, neglecting that for many OHCA patients, prognosis will be defined by their neurologic insult rather than their myocardial injury,” wrote Ragosta, with the University of Virginia Health System. “Addressing their heart first may delay therapeutic hypothermia or delay correction of acidosis, hypotension, or hypoxemia thus potentially extending their neurologic injury.”
Ragosta said the field needs randomized trials evaluating the utility of immediate versus delayed angiography for non-STEMI patients based on scoring systems such as CAPH.
“Such studies would inform our decisions and advance the science of resuscitation medicine,” he said. “Until then, we will continue to observe variation in care in the management of post-resuscitation patients with decisions regarding emergency angiography made on an individual and mostly uninformed basis.”