Study Assesses the Utility of the Destination Therapy Risk Score in Patients with Continuous Flow LVADs

McGowan Institute for Regenerative Medicine affiliated faculty member Jeffrey Teuteberg, MD, assistant professor of medicine, associate director of the Heart Transplant Program, member of the Heart Failure/Cardiac Transplant section, and medical director, Mechanical Circulatory Support Program, University of Pittsburgh Medical Center (UPMC), and faculty member Robert Kormos, MD, professor with tenure specializing in cardiothoracic surgery at the University of Pittsburgh, director of UPMC’s Artificial Heart and Program, and co-director of the Heart Transplant Program, and colleagues authored a recent study which looked to test the usefulness of the Destination Therapy Risk Score (DTRS) in patients with continuous flow left ventricular assist devices (LVAD). The DTRS was developed to predict the risk of 90-day in-hospital mortality with pulsatile flow LVAD as destination therapy (DT).

The study, titled “Risk Assessment for Continuous Flow Left Ventricular Assist Devices: Does the Destination Therapy Risk Score Work? An Analysis of Over 1,000 Patients,” established the DTRS in 1,124 patients with the continuous flow HeartMate II LVAD as a bridge to transplant (BTT) and DT and 114 DT patients with the pulsatile flow HeartMate XVE. Patients were divided into low, medium, and high risk groups. Study authors concluded that using DTRS in a large cohort of patients with a continuous flow device demonstrates only a modest ability to predict 90-day in-hospital mortality. For patients with continuous flow devices implanted as BTT, DTRS provides poor discrimination of 2-year mortality. However, for patients implanted as DT, DTRS stratifies patient outcomes over 2 years but does not characterize a group of patients with a futile outcome.

“The DTRS doesn’t work very well for BTT patients, so I wouldn’t use it in this setting,” lead investigator Dr. Teuteberg told heartwire. “You get a little bit of risk stratification for the destination-therapy patients, and it might help you talk about the likelihood of success with the patient and help them go in a little better armed for how they might do. But I think we have to look at the DTRS with a little bit of skepticism. We’re still trying to figure out what is a better way to determine how people are going to do after their implant.”

An accompanying editorial, “Timing Isn’t Everything: Donor Heart Allocation in the Present LVAD Era,” congratulates the study authors “for providing … a cautionary tale about prematurely adopting risk predictor models into clinical decision making.”

“Even though this DTRS has been widely applied and almost universally accepted, this score was never sufficiently prospectively validated,” the editorial says. “Not only did the DTRS fail to risk-stratify recipients of a continuous flow pump, but it failed to effectively risk-stratify destination therapy recipients of a HeartMate XVE, a population similar to the derivation cohort. This is an important and timely observation for those working in the field of mechanical support, a field that depends on accurate and effective risk predictor models to advise patients and inform clinical decision making.”