Second INTERMACS annual report: More than 1,000 primary left ventricular assist device implants

The Interagency Registry For Mechanical Circulatory Support (INTERMACS)1 an NHLBI-sponsored collaboration between the National Heart, Lung, and Blood Institute (NHLBI), the Food and Drug Administration (FDA), the Center for Medicaid and Medicare Services (CMS), and the advanced heart failure/mechanical circulatory support professional community, began prospective patient enrollment and data collection on June 23, 2006. On 3/27/09, CMS mandated that all United States hospitals approved for mechanical circulatory support as Destination Therapy (DT) must enter mechanical circulatory support patient data into a national database, INTERMACS. The power of INTERMACS data stems from the mandatory data submission on all durable mechanical circulatory devices, a formal process for adverse event adjudication, dedicated innovative electronic data submission, data element design to create a template for comparison with medical therapy, rigorous data monitoring, hospital auditing through the United Network of Organ Sharing, and a formal process for data access and publications. Since the inception of INTERMACS, an ongoing evolution of both strategies for device application and the types of available devices has continued to refine the landscape of mechanical circulatory support. Throughout this experience, the only device approved in the United States for permanent “destination” therapy was the HeartMate XVE2, a pulsatile ventricular assist device which is now known to frequently develop bearing wear and require device replacement within 2 years of implantation. Yet, in many countries outside the United States, newer axial flow and centrifugal flow rotary pumps provide chronic circulatory support. INTERMACS only collects data on devices which are FDA-approved for clinical use, and no adult rotary pump was approved in the United States for the first several years of the INTERMACS experience. The spectrum of devices entered into INTERMACS must also be viewed in the context of multiple concurrent U.S. clinical trials of continuous flow pumps implanted as bridge-to-transplant therapy as well as permanent support. Thus, for the first 2 years, despite the rigorous requirements for data completeness and accuracy, INTERMACS suffered from its inability to collect data on newer, more promising rotary pumps which were not yet FDA approved. The INTERMACS playing field changed dramatically in April of 2008, when the HeartMate II axial flow pump received FDA approval for clinical use as bridge-to-transplant therapy in the United States. A portion of this report will examine the changing practice patterns in the application of device type (continuous flow vs. pulsatile) and device strategies over the past three years. In fact, the genesis of INTERMACS, partly by chance and partly by design, uniquely positioned this database to observe, record, and analyze this historical transition (at least for the immediate future) from larger, powerful pulsatile pumps to the world of continuous flow technology, with the unproven promise of greater durability while retaining long-term patient functionality. This report begins the process of long-term evaluation of continuous flow technology against the background of a large registry of detailed patient and device data based on pulsatile pump technology.