A roadmap for evaluating the use and value of durable ventricular assist device therapy

Abstract

Heart failure is a disease characterized by profound human suffering with limitations in survival despite treatment with guideline-directed medical therapies. Patients with heart failure frequently progress to advanced stages and often require cardiac transplantation or implantation of left ventricular assist devices (LVADs) to extend survival and improve quality of life. As the number of suitable heart donors, number of experienced medical centers and patient comorbidities place restrictions on the feasibility of cardiac transplantation, implantation of LVADs has emerged as a more frequently applied treatment as either a bridge to transplantation or as permanent therapy. Considerable data have documented improvements in survival, functional status and quality of life offered by LVADs, however, few studies have focused on identifying: (1) determinants of LVAD use across medical centers, (2) the relationship between the determinants of LVAD use and value (defined as quality divided by cost), and (3) how determinants of LVAD use are influenced or impacted by vulnerable populations. We propose a conceptual model that integrates the main determinants of LVAD utilization, which include technology, insurance coverage, market-, provider- and patient-level factors. We propose this paradigm as a necessary prerequisite for understanding LVAD usage and value. This conceptual framework provides a broader view for future studies, which are needed to inform emerging healthcare policies that influence dissemination of this expensive but life-prolonging medical therapy.

Keywords: bridge to transplant; durable LVAD therapy; factors; heart failure; left ventricular assist device.

Figure 1:

Our conceptual model integrates several factors determining LVAD use, including technology, insurer, and market-, provider-and patient-level factors. Technologic improvements can be iterative, such as the incremental improvements to reduce the rate of adverse events, or transformative, as evidenced by the shift from pulsatile to continuous flow LVADs. Insurer type has enormous implications for affecting trends in LVAD use (e.g., the inclusion of destination therapy as an indication in the Centers for Medicare and Medicaid Services National Coverage Determination led to a surge in VAD use beginning in 2008). Market-level factors account for proximity of alternate centers, which may influence thresholds for LVAD use depending on local or regional competition. Provider-level factors account for procedure volume and the offering of transplant services because these may affect clinical outcomes. Patient-level factors include characteristics such as age, sex, race, comorbidities, geography and patient preference.

Figure 2:

Key clinical trials for left ventricular assist devices (LVADs) are represented as a function of annual LVAD volume (source Interagency Registry for Mechanically Assisted Circulatory Support [INTERMACS] registry). Of note, the corresponding year of each clinical trial represents the date of publication of major findings from the trial. Although recent trials from 2017 (i.e., HeartWare HVAD [HeartWare Int.] A Clinical Trial to Evaluate the HeartWare® Ventricular Assist System [ENDURANCE], ENDURANCE II, HeartMate 3 [Abbott Laboratories] Multicenter Study of MagLev Technology in Patients Undergoing Mechanical Circulatory Support Therapy with HeartMate 3 [MOMENTUM 3]) are displayed, INTERMACS has yet to publish for the years 2016 and 2017. ADVANCE, HeartWare Left Ventricular Assist Device for the Treatment of Advanced Heart Failure; BTT, bridge to transplant; DT, destination therapy; FDA, Food and Drug Administration.