Impella heart pumps have been associated with serious complications in critically ill patients who require a pump to support circulation as part of stent procedures.
Cardiologists at Washington University School of Medicine have found that Impella pumps are associated with an increased risk of bleeding, kidney problems, stroke and death in patients undergoing stent procedures.
Washington University associate professor of medicine Amit Amin said: “These data are observational, so they can’t prove causation. But they underscore the need for large, randomized clinical trials and prospective registries to better understand and guide the use of cardiac support devices.”
Most patients undergoing stent procedures don’t need a pump as well, but around 3-5% require a ventricular assist device. Impella pumps have small rotors that create a continuous flow of blood. Balloon pumps, which have been in use since the 1960s, are designed to rhythmically inflate and deflate in coordination with the heart’s natural rhythm to help push blood through the vessels.
The Impella pump was associated with a 24% higher risk of death than a balloon pump, and a 34% increased risk of stroke. In no category was the Impella pump associated with improved outcomes.
The team used data from the Premier Healthcare Database, which included information from 48,000 patients treated at 432 US hospitals. Just under 10% of these patients received an Impella pump, while the remaining 90% received an intra-aortic balloon pump.
The data came from patients treated between 2004 and 2016. As the Impella pump wasn’t introduced until 2008, the researchers were able to compare time periods before and after the device came into use.
The researchers also found large variations in how hospitals used the pumps. Hospitals that frequently used Impella pumps had higher adverse outcomes and higher costs associated with caring for patients with heart pumps, despite a trend for lower Impella use among more critically ill patients.
Amin said: “These mechanical support devices are innovative and can efficiently pump blood to the body, but in this study, we found no association with improved outcomes with the Impella pumps.
“This warrants more study so we can understand which patients are likely to benefit from these cardiac assist devices and which are more likely to develop problems.”
Massachusetts-based circulatory support specialist Abiomed took ownership of the Impella technology in 2005 when it acquired German device developer Impella CardioSystems for a reported upfront cost of around $45m.
Abiomed’s stock now has declined 10.89% to $198.93 in trading.
Since the time of writing, Abiomed has contacted Medical Device Network to respond to the study’s findings. The company maintains that the Washington University research is “fundamentally flawed because it is based on poor quality, retrospective, payer coding data that lumps all indications together and is impossible to properly propensity match”.
The company maintains that Impella patients are in fact older and sicker than balloon pump patients, that the authors of the study’s opinions conflict with numerous sets of US Food and Drug Administration (FDA) ratified, peer-reviewed and real-world data and that the analysis removed patients who were escalated to other therapies, which is the major driver of costs and poor outcomes for IABP.
Abiomed medical director Dr Seth Bilazarian said: “Impella is the most studied mechanical circulatory support device in the history of the FDA with real world clinical data on more than 100,000 patients and more than 550 peer-reviewed publications. The FDA granted Impella its highest level of regulatory approval based on this robust clinical data, and eight clinical societies include Impella in their guidelines.”