A new study appearing in the Journal of the American Medical Association (JAMA) on Monday has found that patients having Impella circulatory support device are associated with significantly higher risk of major bleeding and death. This was observed in patients who were implanted with mechanical circulatory support devices and had history of myocardial infarction and cardiogenic shock.
“This is the largest study examining real-world outcomes with both of these devices to date, and our results were consistent,” said Nihar Desai, MD, the study leader and an associate professor of cardiovascular medicine at Yale.
Myocardial infarction, commonly referred to as heart attack, occurs when blood flow to the heart stops or decreases causing damage to the heart muscle. Whereas in cardiogenic shock the heart suddenly cannot pump enough blood to meet the body’s demand. Cardiogenic shock is the leading cause of death in acute myocardial infarction. The morality rate in such conditions can be up to 35% generally and 70-90% in the absence of specialized care.
Usually, in an event of cardiogenic shock fluids, plasma and medications are given through an IV, to increase the heart’s pumping ability. Patients may also be given norepinephrine (Levophed) or dopamine, to improve heart function, till other treatments begin to work. However, treatment with inotropic agents in the event of cardiogenic shock can result in an increased oxygen demand and development of myocardial tissue, which can further lead to irreversible injury to already compromised myocardial tissue.
So, it is paramount to introduce and work on new mechanical devices which can help prevent such an occurrence. These devices include the Impella and the intra-aortic balloon pump (IABP).
Impella ventricular support system (Abiomed) helps with blood pumping by bypassing left ventricle completely or partially. The blood is drawn out of the heart and into the aorta. The device is usually implanted in the left side of the heart, by making a small incision on the femoral artery of the leg.
The Impella is a catheter mounted pump that works on the principle of Archimedes’ screw and was first developed by Dr. Thornsten Siess and colleagues at Impella Cariotechnik AG. The use of the device is based on the degree of cardiogenic shock and physician preference. The US Food and Drug Administration (FDA) has previously approved its use for six hours but the off-label use can be from few hours to 12 days.
On the other hand, an IABP is a thin, flexible tube, called a catheter with an attached balloon. Not everyone can use an IABP either. This includes people with leaky aortic valve or aortic aneurysms.
The propensity-matched registry-based retrospective cohort study was funded by CERSI grant awarded to Yale University and Mayo Clinic by the FDA and the American College of Cardiology’s National Cardiovascular Data Registry. Patients who were implanted with the Impella or the intra-aortic balloon pump (IABP) after a cardiogenic shock were studied for death and bleeding.
The results showed that the use of Impella was associated with an increased risk of in-hospital death by 10.9% and a 15.3% increased chance of a major bleed, compared to the use of an IABP. However, the researchers did warn that the study was not a randomized trial and further research may be needed to understand and adopt the optimal device for these patients.