New AHA Statement Clarifies Cath Lab Role in Out-of-Hospital Cardiac Arrest

A new scientific statement from the American Heart Association (AHA) on catheterization laboratory management of out-of-hospital cardiac arrest (OHCA) aims to help clinicians navigate an often-challenging decision-making process.

The statement, published in Circulation (Epub 2023 Dec 19), follows previous societal documents addressing OHCA management (J Am Coll Cardiol.2015;66[1]:62-73 and Catheter Cardiovasc Interv. 2020;96[4]:844-861), but it delves into much more detail and incorporates more recent trial data, says Cleveland Clinic interventional cardiologist Jacqueline Tamis-Holland, MD, who chaired the writing committee for the new AHA statement.

“Over the past few years, many new studies exploring the catheterization laboratory management of cardiac arrest have been released, and a lot has changed since publication of the earlier documents, so we felt a new statement was needed,” says Dr. Tamis-Holland, who was a co-author on some of the previous papers. “The concepts related to selection of patients for the catheterization laboratory remains the same, with a focus on individualized care.”

What makes the new document unique, says writing committee vice chair Venu Menon, MD, also of Cleveland Clinic, “is that rather than looking at sudden out-of-hospital cardiac arrest from an EMS or emergency room physician’s perspective, this looks at it through the lens of an interventional cardiologist.”

He adds: “This statement recognizes that decision-making is not dichotomous and is much more nuanced when one is addressing the competing risks of acute ischemic cardiac injury and acute irreversible anoxic brain damage. It lays out several gray areas and allows clinicians by the bedside to use a broad number of variables to individualize whether a procedure is appropriate for the patient in front of them.”

The burden of OHCA

OHCA accounts for 15% to 20% of all natural deaths in the U.S. and roughly half of all cardiovascular deaths. Approximately 350,000 Americans experience OHCA annually, of whom less than 10% survive to hospital discharge.

However, the survival rate approaches 30% for those who receive either bystander assistance with cardiopulmonary resuscitation (CPR) or automated external defibrillation that results in return of spontaneous circulation (ROSC) within 15 minutes, as well as having evidence of ST-segment elevation on initial ECG following ROSC. Survival rates are also higher within coordinated systems of care with emergency access to the cardiac catheterization lab as well as use of extracorporeal membrane oxygenation (ECMO) in select patients.

Statement at a glance

The first few sections of the statement cover epidemiology and risk factors for OHCA, pathogenesis, initial assessment (history and electrocardiographic, hemodynamic and neurological evaluation) and imaging. A table lists available clinical risk prediction scores for post-OHCA outcomes based on the patient’s characteristics before, during and after their cardiac arrest.

Later sections address the role of emergency cardiac catheterization, coronary angiography and intervention, with an algorithm for invasive management. Two pathways are outlined: one for the patient with ROSC in the field, and another for those without ROSC after three shocks or within 10 minutes of CPR with at least one shock.

Essentials of pathways with and without ROSC

When ROSC is achieved in the field, the next step is to obtain a 12-lead ECG and transfer the patient to a hospital capable of providing comprehensive post-arrest care. Cleveland Clinic manages about 50 to 60 such patients a year, says Dr. Menon, who directs Cleveland Clinic’s cardiac intensive care unit.

A combination of factors should be assessed to determine whether invasive care in the cath lab would be potentially beneficial or more likely futile. Clinical factors associated with poor neurologic outcome include advanced age, unwitnessed arrest, no bystander CPR, nonshockable rhythm on initial assessment and prolonged duration of cardiac arrest before ROSC. Additional predictors of poor prognosis include elevated lactic acid levels (> 7), low pH (< 7.2) or diffuse cerebral edema on CT at presentation.

In general, more than six of these unfavorable features should trigger “thoughtful consideration of the appropriateness of invasive therapies,” the statement says.

“There’s a lot of controversy,” Dr. Tamis-Holland observes. “Some clinicians feel that all cardiac arrest patients should go to the cath lab, irrespective of the likelihood for neurologic recovery. Others feel that when there’s futility, resources would be better directed elsewhere. We are not against adoption of a strategy of sending anyone emergently to the cath lab, even if the prognosis is poor, but we do emphasize the importance of thoughtful considerations in all cases. I think this document provides clinicians some confidence in how they should manage these patients.”

For patients who don’t achieve ROSC in the field, the second pathway in the algorithm advises consideration of transport with extracorporeal cardiopulmonary resuscitation (ECPR) in regions where that procedure is available and for patients who meet specific criteria. These include age less than 75 years, witnessed arrest and expected initiation of ECMO within 45 minutes.

“In the statement we discuss the essential elements an institution and a community need to have in place to have effective ECPR programs, including a close relationship with EMS and the ability to rapidly place a patient on ECMO,” Dr. Tamis-Holland says. “This was one of the sections we most enjoyed writing, and we hope it’s useful to the reader.”

Sizing up current data, future research needs

The document summarizes results from three randomized clinical trials of ECPR that produced divergent conclusions, as well as available data for cardiac catheterization use in the specific circumstances of cardiac arrest with and without ST-segment elevation on ECG, with cardiogenic shock, and with massive pulmonary embolism.

It concludes with sections on best practices for cath lab management, intensive care management, systems of care for OHCA, public reporting of OHCA outcomes, and future directions and considerations for research.