Mortality rates for patients with VADs decline even as readmission rates remain steady

February 3, 2014 – DCRI Fellow Prateeti Khazanie, MD, MPH, led the retrospective cohort study of Medicare patients with heart failure who received ventricular assist devices.

Rates of death among Medicare patients who received ventricular assist devices (VADs) have improved over time, but rates of hospital readmission have remained largely unchanged.

That is the finding of a new study by DCRI and Duke researchers published online last week in the Journal of the American College of Cardiology. The study was led by DCRI Fellow Prateeti Khazanie, MD, MPH (pictured); with Bradley Hammill, MS; Chetan Patel, MD; Zubin Eapen, MD; Eric Peterson, MD, MPH; Joseph Rogers, MD; Carmelo Milano, MD; Lesley Curtis, PhD; and Adrian Hernandez, MD, MHS.

prateeti-khazanie-newsVADs are a relatively recent development in cardiovascular care. Prior to their development, treatment options for patients with end-stage heart failure were limited to heart transplants. Because of a chronic shortage of available hearts, however, many patients died while waiting for a transplant. The introduction and ongoing improvement of VADs has provided clinicians with another option for these patients. Because widespread use of VADs is a relatively new phenomenon, there has been little research into long-term outcomes or the relationship between facility volume and patient outcomes.

In the current study, Khazanie and her colleagues sought to describe trends in short-term and long-term mortality, readmission, relationships between facility volume and patient outcomes, and costs among Medicare beneficiaries receiving VADs between 2006 and 2011. To do so, the researchers analyzed Medicare inpatient claims to identify all patients who received a VAD during that time period. They then examined mortality rates in-hospital and at 1 year after VAD implantation. The researchers also examined rates of heart transplant, all-cause readmission, and cardiovascular readmission for 1 year after discharge, as well as costs over time.

Of the 2,507 patients who received a VAD at 103 centers during the study period, in-hospital mortality declined from 30 percent to 10 percent, 1-year mortality declined from 42 percent to 26 percent, and all-cause readmission remained frequent (82 percent in 2006, 81 percent in 2011). After covariate adjustment, in-hospital and 1-year mortality declined, but all-cause readmission did not change. Hospitals with low procedure volume had higher risks of in-hospital and 1-year mortality compared with high-volume hospitals. Procedure volume was not associated with risk of readmission. The largest cost was from the index hospitalization and remained unchanged from 2006 ($204,020) to 2011 ($201,026).

These findings, the researchers concluded, suggest that improvements in VAD technology and clinicians’ growing experience with the devices may be responsible for declining mortality rates. That experience may also be why high-volume centers have lower risks of mortality than low-volume centers. Additional research is needed to better understand these patterns, they said.