Risk factors for heart transplant survival with greater than 5 h of donor heart ischemic time

Abstract

Objective: Implantation of donor hearts with prolonged ischemic times is associated with worse survival. We sought to identify risk factors that modulate the effects of prolonged preservation.

Methods: Retrospective review of the United Network for Organ Sharing database (2000-2018) to identify transplants with >5 (n = 1526) or ≤5 h (n = 35,733) of donor heart preservation. In transplanted hearts preserved for >5 h, Cox-proportional hazards identify modifiers for survival.

Results: Compared to ≤5 h, transplanted patients with >5 h of preservation spent less time in status 1B (76 ± 160 vs. 85 ± 173 days, p = .027), more commonly had ischemic cardiomyopathy (42.3% vs. 38.3%, p = .002), and less commonly received a blood type O heart (45.4% vs. 50.8%, p < .001). Longer heart preservation time was associated with a higher incidence of postoperative stroke (4.5% vs. 2.5%, p < .001), and dialysis (16.4% vs. 10.6%, p < .001). Prolonged preservation was associated with a greater likelihood of death from primary graft dysfunction (2.8% vs. 1.5%, p < .001) but there was no difference in death from acute (2.0% vs. 1.7%, p = .402) or chronic rejection (2.0% vs. 1.9%, p = .618). In transplanted patients with >5 h of heart preservation, multivariable analysis identified greater mortality with ischemic cardiomyopathy etiology (hazard ratio [HR] = 1.36, p < 0.01), pre-transplant dialysis (HR = 1.84, p < .01), pre-transplant extracorporeal membrane oxygenation (ECMO, HR = 2.36, p = .09), and O blood type donor hearts (HR = 1.35, p < .01).

Conclusion: Preservation time >5 h is associated with worse survival. This mortality risk is further amplified by preoperative dialysis and ECMO, ischemic cardiomyopathy etiology, and use of O blood type donor hearts.

Keywords: heart transplant; ischemia/reperfusion injury; outcomes; primary graft dysfunction.

FIGURE 1

Histogram showing frequency of donor ischemic times (A) ≤5 h and (B) >5 h. Frequency distribution curve is for the entire study population (n = 37,259) with a standard deviation of 1.046

FIGURE 2

Survival analysis shows (A) Worse survival for donor heart ischemic times >5 h; and for donor hearts with >5 h of ischemic time, heightened risk for poorer transplant survival occurs for recipients (B) on pre-transplant dialysis, (C) transplanted with O blood type donor hearts, and (D) on pre-transplant ECMO. ECMO, extracorporeal membrane oxygenation