We all know early recognition and early CPR is important for out-of-hospital cardiac arrest patients; however, what is the optimal care when the patient has return of spontaneous circulation? Therapeutic hypothermia is a reasonable first thought, but early coronary catheterization, even in the absence of ST elevation, has been gaining traction, and has been shown to improve outcomes. Several articles published within the last year support the AHA class I guideline that early coronary angiography is the treatment of choice for patients with evidence of STEMI who had an out of hospital cardiac arrest.1 Two recent studies also add to the body of research supporting its use in NSTEMI cardiac arrest patients as well. These studies confirm that earlier cardiac catheterization improves both survival to discharge and increases the number of patients with favorable neurologic outcomes.
Studies confirm that earlier cardiac catheterization improves both survival to discharge and increases the number of patients with favorable neurologic outcomes.
What Does the Data Say?
In a retrospective subgroup analysis of a study of 16,875 total participants, patients who had an out-of-hospital cardiac arrest and ROSC who received a PCI within 24 hours of admission had a significantly better odds of survival to discharge (aOR = 1.69; 95%CI = 1.06-2.70) and discharge with a favorable neurologic outcome (aOR = 1.87; 95%CI = 1.15-3.04) than those who did not.2 A favorable neurologic outcome was defined as a modified Rankin Score <3. These same improved outcomes were also associated with therapeutic hypothermia and a composite of patients who received reperfusion with PCI or fibrinolytics.
One recent meta-analysis of 15 primary studies looking at 1,800 events also confirms that early cardiac catheterization improves survival to discharge (OR = 2.77; 95%CI = 2.06-3.72) and favorable neurologic outcome (OR = 2.20; 95% = 1.46-3.32).3 In this meta-analysis, they separated out studies on cardiac catheterization in STEMI patients only, which showed an overall survival to discharge of 67.4%, with 68.4% having a favorable neurologic outcome. When including studies with both STEMI and NSTEMI patients, overall survival was slightly less, at 47.5%, and discharge with favorable neurologic outcome was also lower, at 50.4%. This shows that early catheterization improves outcome when considering STEMI and NSTEMI patients combined, though not as much as in STEMI patients alone.
What about NSTEMI Patients?
There has been a recent push for more aggressive care of patients with NSTEMI. Currently, the AHA recommends the use of an early invasive strategy in high-risk NSTEMI and unstable angina patients with an MI without other contraindications.4 A review of 6.5 million patient records from 2002 to 2011 showed an increase in the use of early invasive strategies (coronary angiography with or without PCI or CABG) in NSTEMI patients and an associated decrease in hospital length of stay and in-hospital mortality.5 In the nearly 4 million patients with NSTEMI, the use of an early invasive strategy doubled over the study period. The use of an early invasive strategy on day 0 or 1 increased from 27.8% in 2002 to 41.4% in 2011. Over this same time period, hospital length of stay decreased from 5.7 to 4.8 days and overall in-hospital mortality decreased from 5.5% to 3.9%. Notably, those patients who received an early invasive strategy on day 0 had the biggest drop in length of stay and a non-significant drop in in-hospital mortality from 2.5% to 2.0%.
Despite the increase in use of early invasive strategy in NSTEMIs, the use of cardiac catheterization in NSTEMI cardiac arrest remains variable and somewhat controversial. The study mentioned above of 16,875 patients with out of hospital cardiac arrest notes that only 12% of patients with NSTEMI received cardiac catheterization.2
Another retrospective study of 269 patients with NSTEMI cardiac arrest showed that, of those with ROSC, those who had early cardiac catheterization (on admission or while inducing hypothermia) with or without PCI survived to discharge significantly more (aOR = 2.86; 95%CI = 1.43-5.56) than those who did not have a catheterization or did not have it as early.6 Notably, this study excluded patients with arrhythmias other than ventricular tachycardia or ventricular fibrillation, and those with unknown arrhythmias. This study also supports that even patients with NSTEMI post cardiac arrest can benefit from early catheterization. Indeed, of these NSTEMI patients, 66% of them ended up having a PCI during their cardiac catheterization. This study also showed a higher use of cardiac catheterization (60.5%) during the period they examined (2005 to 2011) than the other two studies already mentioned.2,4
What Does All of This Mean?
All of this data works to confirm the AHA guideline1 that coronary angiography should be initiated immediately in patients who have ROSC after an out of hospital cardiac arrest with evidence of STEMI. They also suggest that NSTEMI patients who survive out of hospital cardiac arrest may also benefit from immediate cardiac catheterization as well. While these studies defined “early” catheterization very differently (immediately on admission or up to 24 hours after admission), it still appears that catheterization within 24 hours of admission is associated with improved survival, and survival with good neurological outcome. As with most treatments in cardiac arrest patients, it appears the earlier you start, the better the outcome.
In addition to therapeutic hypothermia, immediate cardiac catheterization should be incorporated into hospital protocols and clinical management of patients with ROSC after cardiac arrest. Nearly all studies to date have shown improved outcomes in patients with STEMI and ROSC. Although far from irrefutable evidence, it appears that NSTEMI patients who survive out of hospital cardiac arrest also benefit from early catheterization, though maybe to a lesser degree. Consider the importance of time to catheterization in all of your cardiac arrest patients with ROSC. The data suggests that we should be liberal with getting the interventionalists involved, and by so doing, my improve the outcomes of our patients.
- O'Gara PT, Kushner FG, Ascheim DD, et al. 2013 ACCF/AHA guideline for the management of ST-elevation myocardial infarction: A report of the american college of cardiology Foundation/American heart association task force on practice guidelines. Circulation. 2013;127:e362–425.
- Callaway CW, Schmicker RH, Brown SP, et al. Early coronary angiography and induced hypothermia are associated with survival and functional recovery after out-of-hospital cardiac arrest. Resuscitation. 2014;85(5):657-663.
- Camuglia AC, Randhawa VK, Lavi S, Walters DL. Cardiac Catheterization is associated with superior outcomes for survivors of out of hospital cardiac arrest: a review and meta-analysis. Resuscitation. 2014;85(11):1533-1540.
- Jneid H, Anderson JL, Wright RS, et al. 2012 ACCF/AHA focused update of the guideline for the management of patients with unstable angina/non-ST-elevation myocardial infarction (updating the 2007 guideline and replacing the 2011 focused update): a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol 2012;60:645-81.
- Khera S, Kolte D, Aronow WS, et al. Non-ST-elevation myocardial infarction in the United States: contemporary trends in incidence, utilization of the early invasive strategy, and in-hospital outcomes. J Am Heart Assoc. 2014;3(4).
- Hollenbeck RD, McPherson JA, Mooney MR, et al. Early cardiac catheterization is associated with improved survival in comatose survivors of cardiac arrest without STEMI. Resuscitation. 2014;85(1):88–95.