AHA: Is ECMO the wave of the future?

NEWTON, Mass.—“Everyone who receives ECMO [extracorporeal membrane oxygenation] does not die,” said Joshua N. Baker, MD, a cardiovascular surgeon at Massachusetts General Hospital (MGH) in Boston, during a presentation April 26 at the American Heart Association's 22nd Annual Cardiovascular Nursing Conference. While ECMO is still sparsely used in the U.S., there may be ground for more widespread acceptance despite the costs, he told Cardiovascular Business.

"The most important thing was convincing a lot of people, even in our institution, was that everyone who undergoes ECMO does not die," he said. "In fact, there are a lot of patients who can be saved."

MGH is one of the few sites in the U.S. using ECMO in patients. During his lecture, Baker touched on how the hospital made it work and where the future of this technology is headed.

What is ECMO? A heart and lung device outside the patient’s body that takes over the work for the heart and lungs, Baker said. Key components of ECMO include an oxygenator/heat exchanger; a blood pump; conduit tubing that includes a heparin substance that allows the clinician to stop anticoagulation; and a heater/cooler.

Baker talked about the two most common types of ECMO— venovenous ECMO (VV ECMO) and venoarterial ECMO (VA ECMO). While VV ECMO is typically used for respiratory failure, VA ECMO provides biventricular support for cardiac failure.

Contraindications of ECMO include neurologic catastrophe, patients with an active uncontrolled malignancy, age above 80 and any major medical problems that would make recovery difficult. 

“When teaching about ECMO, I tell my residents that the patient has a left side of the heart, a right side of heart and the lungs. If any two of those are down, really the only thing we can do is do the VA ECMO because it provides biventricular support and provides oxygenation and carbon dioxide support,” said Baker.

He cited a recent study that examined 30-day death rates of cardiogenic shock patients who did not undergo ECMO support. The death rates were reported to be 72 percent for those who did not receive ECMO compared with 40 percent for those who did receive ECMO support. “The absolute risk reduction was around 30 percent,” Baker said. “This means the number to treat was three. There aren’t many other things in medicine where you only need to treat three patients to save a life.”

To treat these patients, MGH has instituted the SHOCK team approach, which includes an algorithm for how to properly treat patients who may need ECMO. “The SHOCK program was a way to get patients who were in cardiogenic shock who might benefit from a temporary left ventricular assist device or ECMO into the system before they got so sick that they weren’t recoverable,” Baker said in an interview after the presentation.

He added that the SHOCK team has the same mantra as the recently proposed STROKE team concept where there is a window to perform an intervention that can possibly help improve the health of the patient.

The heart failure and surgery teams, along with cardiac surgeons, intensivists and nurses work together to initiate ECMO. While there are a plethora of device technologies, Baker said if a patient has right ventricle and left ventricle failure, the only option is ECMO.

While Baker said that the cannulation can usually be done in a few minutes, the most difficult aspect of ECMO is patient management post-procedure. “It’s not just fire and forget,” Baker said. The strategy requires a multidisciplinary team of nurses, surgeons, respiratory care experts, etc., to assist in the patient’s post-care management.  

Today, only a few hundred patients undergo ECMO annually. Consequently, there is a lack of data outlining ECMO and its outcomes.  

In-house ECMO mortality rates at MGH are just above 30 percent and nestled within the national average. However, for primary shock patients the in-house mortality rates are just more than 50 percent. But, Baker offered that the most intriguing statistics might be from STEMI patients who present to the emergency room and undergo CPR. Of the three STEMI patients who underwent ECMO, all survived.

“Part of this maybe the fact that the cath lab nurses at MGH give the most vigorous CPR I’ve ever seen,” Baker said.

To date, MGH has performed ECMO on 32 patients. ECMO has come a long way since 1979 when an MGH study showed that survival curves were similar with ECMO and without. This is where the notion that “everyone who gets ECMO dies” came from, Baker said.

What is the difference between then and now? Baker said that now staff has a better understanding of patient physiology. Also, a multidisciplinary approach that includes nurses, ECMO therapists and perfusionists helps with post-ECMO patient management.

“An interdisciplinary team with round-the-clock availability might lead to successful clinical results in such cases," Baker said.

If the technology is so beneficial, why isn't everyone doing it?

“It’s really expensive,” he noted. Pump costs hover around $90,000, and having enough highly educated, high-functioning nurses and respiratory therapists is also expensive. Baker estimated the disposable costs to be between $12,000 to $13,000.

“Some centers may be able to use a core group of individuals who can put patients on ECMO and then transfer them for the management portion of patient care, which is the very time-consuming part,” Baker offered.  

“Good results are achieved by finessed patient selection,” he summed. “A lot of these patients will not get better and it won’t be appropriate to the family to put the patient on ECMO. You should avoid ECMO in these types of situations."