HLA Allosensitization in Patients on Continuous Flow LVAD Support: Are Patients at Increased Risk?

Abstract

Allosensitization poses a challenge in identifying appropriate donors for patients (pts) awaiting cardiac transplantation. Continuous flow left ventricular assist device (LVAD) can induce significant allosensitization to human leucocyte antigens (HLA). With advances in surgical approaches and improved LVAD hemocompatibility, the prevalence of allosensitization is not well studied. We evaluated the development of allosensitization in a contemporary LVAD cohort including centrifugal and axial LVADs. In consecutive pts who underwent LVAD in a single center from 2014 to 2018, we examined HLA immune status prior to LVAD and at time of transplant if less than one year or up to one year of LVAD support. Serum alloantibodies were detected with single-antigen beads using a Luminex platform. HLA allosensitization was defined as having a calculated panel reactive antibody (cPRA) >10%. LVAD-associated allosensitization was defined as having a cPRA >10% and cPRA <10% before LVAD. A total of 50 pts who underwent LVAD implantation as bridge to transplant had available cPRA prior to and after LVAD implantation. Mean follow up was 268±91 days. Mean age was 53±13 years, and 26% were female. 18 pts (36%) had centrifugal LVAD. At 1 year, 28 pts (56%) were transplanted, 18 pts (36%) remained on LVAD support, and 4 pts (8%) expired. Of the 50 patients, 14% (n=7) had PRA over 10%. Though the proportion of patients with allosensitization after LVAD increased to 24%, this was not statistically significant (Fig 1A&B). Eight pts had LVAD-associated allosensitization, and in this group, type of device (centrifugal vs axial) was not associated with allosensitization. In our single-center, contemporary cohort, allosensitization before LVAD was not common. LVAD associated allosensitization occurred in about one-fifth of patients.