VA (Venoarterial) Extracorporeal Membrane Oxygenation (ECMO)

VA (Venoarterial) Extracorporeal Membrane Oxygenation (ECMO) is one form of advanced mechanical circulatory support that provides a form of heart and/or lung assist. For example, VA ECMO provides support for the hearts of patients with CAD or heart attacks that reduce the ability of the heart to pump blood with a significantly decreased cardiac output. Below is a description of ischemic cardiomyopathy, as well as an explanation of why and how VA ECMO is applied in the management of patients with ischemic cardiomyopathy.

Ischemic cardiomyopathy is a type of cardiomyopathy and a precursor of heart failure caused by reduced blood supply to the heart. This results in the impairment of the heart muscles’ ability to pump blood. Ischemic cardiomyopathy can be acute or chronic and occurs when the coronary arteries narrow or are blocked by coronary artery disease or a heart attack.

VA ECMO use in the management of ischemic cardiomyopathy

Support of the heart: VA ECMO is employed to provide circulatory support to patients with ischemic cardiomyopathy who present with severe forms of the disease and whose condition does not respond to drug therapy or intra-aortic balloon pump (IABP). The VA ECMO machine helps to reduce the workload of the heart by allowing blood to flow through the lungs to be oxygenated before being pumped back into the bloodstream. In other words, the VA ECMO is used to take over the work of the heart thus giving it a chance to rest and heal. In VA ECMO, blood is withdrawn from the right atrium, and oxygenated and pumped into the femoral artery, thus bypassing the heart.

Reasons for VA ECMO use in ischemic cardiomyopathy

The main reason why people with ischemic cardiomyopathy receive VA ECMO is that it can rapidly improve the situation of patients with heart failure. The common indications for VA ECMO in the management of ischemic cardiomyopathy include:

• Refractory cardiogenic shock due to ischemic cardiomyopathy;

• Cardiac arrest due to ischemic cardiomyopathy;

• Bridge to recovery or transplantation.

Physiological benefit VA ECMO provides for ischemic cardiomyopathy

Improves hemodynamics: VA ECMO helps to increase or maintain blood pressure in the artery.

Bridge to recovery: In the management of acute myocardial infarction, the VA ECMO machine can help to recover the heart while also circulating oxygen-rich blood throughout the body. This is an especially important benefit in the case of ischemic cardiomyopathy as the heart has weak pumping action due to inadequate blood supply; therefore, with VA ECMO, the patient has a good opportunity to recover. The recovery can occur via percutaneous interventions or bypass grafting. Additionally, VA ECMO can also be used as a bridge to heart transplant to give the patient a new heart if the existing one is beyond repair.

Bridge to transplant: This refers to a situation where the patient is placed on VA ECMO as a bridge to heart transplant.

Physiological risks VA ECMO presents for the patient with ischemic cardiomyopathy

Bleeding: Due to the nature of the VA ECMO circuit, patients are placed on blood thinners that make the risk of bleeding higher.

Infections: Since VA ECMO is an invasive therapy and the patients have to stay on it for a relatively long time, the risk of acquiring infections is greater.

End-organ injury: The VA ECMO access can cause injury to the nerves and lead to renal failure, neurologic damage, and leg ischemia.

Clinical significance of using VA ECMO for ischemic cardiomyopathy.

Overall, the application of VA ECMO in the management of patients with ischemic cardiomyopathy is considered a life-saving procedure. However, the prognosis of patients with ischemic cardiomyopathy largely depends on their general condition as well as the state of their heart. Therefore, VA ECMO is mainly indicated as a bridge to recovery or a bridge to heart transplant while the patient is on the machine.