Feature | July 15, 2011| By Jane Luu, M.D., and John Kao, M.D., FACC

Therapeutic Hypothermia in the Cath Lab

STEMI patients surviving cardiac arrest may benefit with preserved neurologic function

The Medivance noninvasive Arctic Sun 5000 therapeutic temperature management system uses external gel pads to regulate temperature, controlled by a touch-screen interface. The system gained U.S. Food and Drug Administration (FDA)-clearance in the fall of 2010.

The Medivance noninvasive Arctic Sun 5000 therapeutic temperature management system uses external gel pads to regulate temperature, controlled by a touch-screen interface. The system gained U.S. Food and Drug Administration (FDA)-clearance in the fall of 2010.

Each year, more than 300,000 people in the United States suffer sudden cardiac death, with some estimates placing this number as high as 460,000. The prognosis after a cardiac arrest is extremely poor; only 18 percent with an in-hospital arrest and less than 10 percent of patients with an out-of-hospital arrest survive to discharge. Unfortunately, poor outcomes continue to dog the few survivors of cardiac arrest, with many of these patients suffering from post-arrest anoxic brain injury, leading to further disability and death.


Landmark Studies
In 2002, two landmark studies assessing the use of therapeutic hypothermia in cardiac arrest patients changed the course of post cardiac arrest management. The first was an Australian study that randomized 77 patients with out-of-hospital ventricular fibrillation (VF) cardiac arrest with return of spontaneous circulation (ROSC) to therapeutic hypothermia vs. normothermia. The therapeutic hypothermia treatment group was cooled to a target body temperature of 33 degrees Celsius within two hours of ROSC. They were ultimately found to have significantly higher rates of neurologically intact survival (49 percent) compared with the normothermia control group (26 percent). The number needed to treat for this effect was 5 percent.


The Hypothermia after Cardiac Arrest (HACA) trial was a multicentered, randomized trial in Europe that compared therapeutic hypothermia to normothermia in 176 patients with a witnessed VF cardiac arrest with ROSC. The study showed cooling this population to a target temperature of 32-34 degrees Celsius led to a significant mortality benefit (41 percent compared with 55 percent in the control group) as well as significant meaningful neurologic recovery (55 percent compared with 39 percent in the control group). Therapeutic hypothermia is therefore now a class IIa recommendation for out-of-hospital VF cardiac arrest, and a class IIb recommendation for in-hospital arrest and non-VF arrest patients.


Hypothermia in the Cath Lab
The most common cause of cardiac arrest is cardiovascular disease and myocardial ischemia. Several post-mortem studies in cardiac arrest patients have shown that more than 80 percent have high-grade coronary artery stenosis, and up to 29 percent of patients have evidence of plaque rupture or thrombus formation. Immediate angiography in cardiac arrest survivors have demonstrated acute total coronary occlusions in 48 percent and irregular type II lesions suggestive of plaque rupture in 18 percent.


Initiating therapeutic hypothermia while performing primary percutaneous coronary intervention (PCI) in this situation may lead to better outcomes, but the evidence supporting this statement is far from conclusive, as the vast majority of patients in the landmark trials did not receive any revascularization therapies. One observational study showed that rates of meaningful neurological recovery and survival in patients with ST-elevated myocardial infarction (STEMI) and ROSC who remain comatose at the time of PCI are 51 percent. In patients who regain consciousness at the time of PCI, the survival rates were 100 percent and rivaled that of STEMI patients without cardiac arrest. Another observational study in Europe also showed similar rates of survival – 54 percent at six months – using a strategy of therapeutic hypothermia and early revascularization in STEMI patients with cardiac arrest and ROSC.


Initiating hypothermia protocols were not associated with delays to reperfusion in the cath lab. Despite being predominantly observational, the data supports therapeutic hypothermia and early revascularization in cardiac arrest patients with electrocardiogram (ECG) evidence of STEMI. Revascularization strategies in VF patients without ST elevation is less clear and data on non-arrest patients with STEMI have been disappointing with the COOL-MI trial. That study demonstrated a trend towards an increase in adverse events in non-arrest STEMI patients undergoing cooling compared to the normothermia group and the early termination of the COOL-MI II trial without publication of trial results.


First-Hand Experience
Anecdotally, in our own experience, we have witnessed several cases of out-of-hospital arrest and in-hospital arrest that have recovered full neurologic function and walked out of the hospital that we would have otherwise thought to be impossible.


One patient collapsed at home and was found to be in V-fib arrest by paramedics who arrived 30 minutes after the patient was found. The patient was defibrillated five times on the way into the hospital for recurrent V-fib and coded twice more in the emergency department before undergoing emergent PCI of the left anterior descending (LAD) and right coronary artery (RCA).  Neurologic exam prior to being taken to the cath lab demonstrated fixed pupils, absent gag and decerebrate posturing. Our institutional cooling protocol was implemented after successful PCI and to my amazement, the patient started recovering neurologic function on day three post-arrest. They were able to walk out of the hospital a week later.


Two other cases involving a 91-year-old patient with V-fib arrest during vein graft PCI and another out-of-hospital arrest in a patient down for at least 30 minutes demonstrated similar miraculous recoveries.  


Hypothermia for out-of-hospital and in hospital cardiac arrest has been demonstrated to have significant survival and neurologic benefits.  While the data supporting its use in the cardiac cath lab is limited and the number of patients where this protocol would be potentially useful is small – STEMI patients surviving cardiac arrest with persistent comatose state after ROSC – the potential benefit to our patients is extremely high and in our opinion well worth the effort.  


Editor’s note: Jane Luu, M.D., MPH, was recently a third-year cardiology fellow at Virginia Commonweath University Hospital in Richmond, Va., and is now an interventional fellow at Scripps Clinic in La Jolla, Calif. John Kao, M.D., FACC, is director of cardiovascular services at Kapiolani Medical Center and is a member of the DAIC Editorial Board. The medical center uses the Alsius Cool Guard device and the Alsius Icy heat exchange catheter for induction of hypothermia.

Related Content

Abiomed, Impella heart pump, 50,000 patients treated, United States, milestone
News | Ventricular Assist Devices (VAD)| February 24, 2017
Abiomed Inc. announced that it has supported more than 50,000 patients in the U.S. with its Impella line of heart pumps...
coordinated heart attack care, Ontario STEMI Bypass Protocol, Canada
News | Cath Lab| February 22, 2017
Two new Ontario-wide heart attack protocols for paramedic services and emergency departments that aim to saves lives...
transradial approach, same-day cardiac procedures, radial access, $300 million annual savings, JACC Cardiovascular Interventions study
News | Radial Access| February 22, 2017
If hospitals can perform more transradial, same-day percutaneous coronary intervention (PCI), hospitals across the U.S...
Technology | Radial Access| February 17, 2017
Medtronic plc announced that its coronary portfolio will now include the DxTerity Diagnostic Angiography Catheter line...
Sponsored Content | Videos | Inventory Management| February 17, 2017
The supplies you use in your cath lab are complex and very valuable.
Mercator MedSystems, DANCE trial data, ISET, LINC, Bullfrog Micro-Infusion Device
News | Peripheral Arterial Disease (PAD)| February 15, 2017
Mercator MedSystems announced that the national co-principal investigators of the company’s DANCE trial each presented...
Cardinal Health survey, hospital staff, supply chain management, quality of care
News | Inventory Management| February 15, 2017
Better hospital supply chain management leads to better quality of care and supports patient safety, according to a new...
University of Alabama at Birmingham, Amplatzer PFO Occluder, first implementation
News | Structural Heart Occluders| February 15, 2017
Doctors at the University of Alabama at Birmingham have implemented the first U.S. Food and Drug Administration (FDA)-...
Biotronik, PRO-Kinetic Energy cobalt chromium coronary stent system, FDA approval
Technology | Stents Bare Metal| February 15, 2017
The PRO-Kinetic Energy Cobalt Chromium (CoCr) Coronary Stent System from Biotronik has gained U.S. Food and Drug...
heart team, hybird OR, structural heart team

The heart team approach was first used on a large scale in the CoreValve and Sapien TAVR trials and helped lead to excellent outcomes in high-risk patients.

Feature | Hybrid OR| February 15, 2017 | Dave Fornell
In the current era of healthcare reform and the push toward evidence-based medicine to both lower costs and improve p
Overlay Init