Prior Human Leukocyte Antigen-Allosensitization and Left Ventricular Assist Device Type Affect Degree of Post-implantation Human Leukocyte Antigen-Allosensitization

Abstract

Background Temporary use of left ventricular assist devices (LVADs) prior to heart transplantation has been associated with formation of antibodies directed against human leukocyte antigens (HLA), often referred to as sensitization. Identifying specific factors that might predispose patients to form HLA-specific antibodies after LVAD implantation may facilitate the development of strategies to prevent high degree of sensitization. We investigated whether prior sensitization or LVAD type affected the degree of post-implantation sensitization. Methods We reviewed the records of consecutive HeartMate (HM) I and HM II LVAD patients. Panel reactive antibody (PRA) was assessed, either with antiglobulin cytotoxicity or flow cytometry, prior to LVAD implantation and biweekly thereafter. Sensitization was defined as PRA >10% and high degree sensitizization was defined as a PRA >90%. Results Sixty-four patients underwent implantation with a HM I LVAD and 11 patients with a HM II LVAD as a bridge to transplant. Among the HM I patients, 10 (16%) were sensitized before LVAD implantation (HM I-SENSITIZED), averaging a PRA of 50±35 %, and 54 (84%) were not (HM I-NON-SENSITIZED). Nine of 10 HM I-SENSITIZED patients (90%) became highly sensitized (PRA>90%) compared to only 9/54 HM I-NON-SENSITIZED patients (16.7%) (p<0.001). Despite similar duration of mechanical support, the PRA remained elevated (>90%) in all but 1 of the highly sensitized pts in HM I-SENSITIZED (8/9, 88.9%), compared to only 5/9 (55.6%) of the highly sensitized pts in HM I-NON-SENSITIZED. In the rest of the HM I-SENSITIZED highly sensitized pts PRA declined from a peak value of 93±4% to 55±15% (p= 0.01). Among the HM II patients, 1 (9 %) was sensitized before LVAD implantation (PRA 40%) and 10 (91%) were not sensitized. The sensitized HM II patient did not become highly sensitized but did moderately increase the PRA to 80%. No other HM II patient became sensitized after implantation. Thus, fewer HM II patients became sensitized when compared to the HM I patients [1/11 (9%) vs 29/64 (45%); p=0.04]. Conclusion Pre-sensitized patients are at higher risk for becoming and remaining highly HLA-allosensitized after LVAD implantation. Furthermore, HeartMate II LVAD appears to cause less sensitization than HeartMate I LVAD.

Post-transplant Outcomes of Children Bridged to Transplant With the Berlin Heart EXCOR Pediatric Ventricular Assist Device

“…14,[17][18][19] Using the OPTN adult data, Arnaoutakis et al 14 demonstrated that device type (continuous flow versus pulsatile, with higher sensitization rates in latter) or levels of panel-reactive antibody activity (>25% defined as high) were not associated with worse mortality. Furthermore, they found that panel-reactive antibody activity did not affect rejection rates in the first year after transplant.…”

Changing outcomes in patients bridged to heart transplantation with continuous- versus pulsatile-flow ventricular assist devices: An analysis of the registry of the International Society for Heart and Lung Transplantation

“…26 It remains to be seen whether this difference is clinically significant and likely to affect long-term survival.…”

Allosensitization and the Ventricular Assist Device: Dual Evolution of Technology

“…Drakos [13] undertook a study to determine risk factors contributing to allosensitization. They reviewed records of 75 patients, most of whom received the HeartMate I.…”