Prognosis Poor for Primary PCI Patients with Cardiac Arrest Before Ambulance Arrival

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For patients who experience cardiac arrest and subsequently undergo primary percutaneous coronary intervention (PCI), in-hospital rates of death remain high, especially among those who arrest prior to the arrival of an ambulance, according to a study published online May 12, 2014, in European Heart Journal: Acute Cardiovascular Care.

Researchers led by Vijay Kunadian, MD, of Newcastle University (Newcastle upon Tyne, United Kingdom), examined data from a single tertiary cardiac center on 4,118 patients undergoing primary PCI for STEMI between January 2006 and April 2013. Of these, 484 patients sustained cardiac arrest either before ambulance arrival (n = 91), after ambulance arrival (n = 125), in the hospital (n = 87), or in the cath lab (n = 181).

More than half of primary PCIs in cardiac arrest patients were performed radially (57.5%).

Location, Timing of Arrest Linked to Mortality

In-hospital mortality was 20.5% in patients with cardiac arrest vs 2.2% in those without. Analysis by presentation type found that those sustaining cardiac arrest before ambulance arrival experienced the highest unadjusted mortality rate compared with other cardiac arrest groups (29.7%; P = .03 for all comparisons), though notably, the cath lab group had an in-hospital mortality rate of 23.8%.

Compared with those who survived, cardiac arrest patients who died were older (mean age 69.4 vs 61.1 years; P < .0001) and more likely to:

• Be female (P = .0004)
• Present with asystole or electromechanical dissociation (EMD; P < .0001)
• Have 3-vessel disease (P = .0012) or left main disease (P = .0003)
• Present with cardiogenic shock (P = < .0001)
• Be ventilated (P < .0001)
• Have had intraaortic balloon pump therapy (P < .0001)

Variables associated with increased risk of in-hospital mortality on multiple regression analysis were age, female sex, previous PCI, asystole/EMD, and patient location at arrest. In the setting of early cardiac arrest (before hospital arrival), the independent predictors of in-hospital mortality were female sex and patient location at arrest (table 1).

Table 1. Independent Predictors of In-hospital Mortality

^aAbbreviation: EMD, electromechanical dissociation.

Methods Needed to Optimize Outcomes

The study authors say the link between increasing age and in-hospital mortality is consistent with a previous observation that cardiopulmonary resuscitation (CPR) is rarely effective in patients older than 70 years of age with cardiac arrest, regardless of location. Further research is needed to elucidate the reasons for the sex discrepancy seen in the study and to optimize outcomes, they add.

Furthermore, Dr. Kunadian and colleagues say, the study “raises questions as to how (and if) we can reduce this mortality rate for this group of patients.

“While portable defibrillator machines in public places have proven to be successful in saving lives,” they continue, “survival rates to hospital admission and to hospital discharge remain poor among [out-of- hospital cardiac arrest] patients (23.8% and 7.6%, respectively, from a meta-analysis of 79 studies). High-quality chest compression with minimal interruptions is vital for optimizing outcomes. Hence, a mechanical CPR device designed to provide consistent and uninterrupted chest compressions is an attractive proposition, but studies comparing it to manual CPR have yielded conflicting results. Prolonged CPR with extracorporeal membrane oxygenation in selected patients has been associated with acceptable survival rates and neurological outcomes.”

Study Highlights ‘Grim Prognosis’

In a telephone interview with TCTMD, Sripal Bangalore, MD, MHA, of New York University School of Medicine (New York, NY), said studies such as this “unfortunately emphasize the grim prognosis of these patients.”

While the findings are not surprising, he continued, the ability to link patient location at time of arrest to increased mortality provides an important message about “timely intervention and making sure that everything possible is being done to improve prognosis in these patients.”

Likewise, Dr. Kunadian and colleagues say their study “reiterates the need regarding general public education on seeking help (immediate call for help from emergency services) and prompt initiation of resuscitation in order to improve outcomes.”

Dr. Bangalore agreed, stressing that the main message “is clearly for the public and for the bystanders that every second counts.” Though for interventional cardiologists, he added the message is that out-of-hospital cardiac arrest before an ambulance arrives is not the same as cardiac arrest occurring anywhere else.

“From my perspective, knowing that the cardiac arrest occurred before ambulance arrival might very well influence the treatment we undertake,” he commented. Dr. Bangalore added that the number of patients included in the study that arrested in the cath lab and died is surprising and deserves further research.

 

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Source:
Kunadian V, Bawamia B, Maznyczka A, et al. Outcomes following primary percutaneous coronary intervention in the setting of cardiac arrest: a registry database study. Eur Heart J: Acute Cardiovasc Care. 2014;Epub ahead of print.

 

 

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