National trends and outcomes in device-related thromboembolic complications and malfunction among heart transplant candidates supported with continuous-flow left ventricular assist devices in the United States

Abstract

Background: This study evaluated current trends in incidence and outcomes of left ventricular assist device (LVAD)-related thromboembolic (LVAD-TE) and LVAD malfunction (LVAD-M) complications among heart transplant (HT) candidates supported with continuous-flow LVADs. LVAD-TE and LVAD-M are potentially catastrophic complications that may require status upgrade on the HT waiting list. An increased incidence of device thrombosis has been recently observed; however, whether similar trends of LVAD-TE and LVAD-M are observed on the HT waiting list and their effect on outcomes is unknown.

Methods: We analyzed 3,821 HT candidates on continuous-flow LVADs who were registered on the United States waiting list from 2008 to 2014. We evaluated the incidence of LVAD-TE and LVAD-M as well as survival before and after HT.

Results: LVAD-TE occurred in 249 patients (6.5%) and LVAD-M in 210 patients (5.5%). The incidence of LVAD-TE was highest in regions 1, 2, and 9, whereas LVAD-M was highest in regions 9, 1, and 7. The incidence of LVAD-TE and LVAD-M increased after 2011 from 0.04 to 0.10 and from 0.03 to 0.08 events per patient-year (p < 0.0001 for both comparisons). Survival on the waiting list at 2 years was lower in candidates with LVAD-TE (45% vs 72%, p < 0.0001) and LVAD-M (56% vs 71%, p = 0.003) compared with candidates without complications. Post-HT survival was similar between patients with and without LVAD-TE and LVAD-M (p > 0.43 for both outcomes). In patients with LVAD-TE, mortality risk was highest among candidates managed conservatively (hazard ratio, 8.07; p < 0.0001), whereas patients who underwent HT only (hazard ratio, 0.10; p < 0.0001) had the lowest mortality risk and similar to that of patients without LVAD-TE (p = 0.34).

Conclusions: The incidence of LVAD-TE and LVAD-M on the United States waiting list has increased since 2011, with significant regional variation. LVAD-TE and LVAD-M have a detrimental effect on waiting list survival and transplant candidacy. In candidates who develop an LVAD-TE, a conservative approach, without LVAD exchange or HT, carries the highest risk of death. These results should be considered in the ongoing efforts to optimize the allocation of donor hearts.

Keywords: continuous flow; heart transplant; left ventricular assist device; malfunction; thromboembolic complication.