Impact of Donor Consent to Cross Clamp Time on Heart and Lung Allograft Recovery

A. F. Akbar¹, J. Moore. Ruck², A. L. Zhou¹, A. Kalra³, B. L. Shou¹, A. J.. Casillan⁴, A. Kilic⁵, E. L. Bush^6
1Johns Hopkins School of Medicine, Baltimore, Maryland ²Johns Hopkins University School of Medicine, Baltimore, Maryland ³Johns Hopkins School of Medicine; Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania ⁴Johns Hopkins Hospital, Baltimore, Maryland ⁵The Johns Hopkins Hospital, Baltimore, Maryland ⁶The Johns Hopkins University, Dept. of Surgery, Division of Thoracic, Baltimore, Maryland

Purpose: While increasing time between donor consent to cross clamp (CTCC) may increase organ exposure to perfusion fluids and therefore decrease desirability for recovery, animal models have suggested that function-limiting reperfusion injury occurs in lungs recovered soon after brain death. We investigated the relationship between CTCC time and thoracic organ recovery.

Methods: Using United Network for Organ Sharing Registry data, we identified 134,127 deceased donors from 2005-2022 from whom at least one organ was recovered. Donation after circulatory death donors or those with an unknown CTCC time were excluded. Donors were categorized by CTCC quartile: < 26 hours (Q1), 26-36 hours (Q2), 36-51 hours (Q3), >51 hours (Q4). The primary outcome was proportion of donors with heart and lung recovery, transplantation, and discard. Discard was defined as organs recovered but ultimately not used for transplant. Baseline characteristics and outcomes were assessed using Wilcoxon rank sum and chi-square testing for continuous and categorical variables, respectively.

Results: Median CTCC was 36 hours (IQR=26-51). Donors with the shortest CTCC time (Q1 donors) were older, more likely to be white, had a higher rate of smoking, diabetes, hypertension, and cancer, and had a lower rate of cocaine use and pulmonary infection than donors with the longest CTCC time (Q4 donors) (Table 1). Q1 donors more frequently died from stroke while Q4 donors more frequently died from anoxia. The percentage of donors from whom the heart and at least one lung was recovered, respectively, was 18.8% and 12.2% for Q1 donors compared to 50.0% (p < 0.001) and 34.4% (p < 0.001) for Q4 donors (Figure 1). Of donors with the heart recovered, 98.9% of Q1 donors and 99.2% of Q4 donors had the heart transplanted (p=0.050), while 1.1% and 0.8% had the heart discarded (p=0.050). Of donors with at least one lung recovered, 96.5% of Q1 donors and 96.6% of Q4 donors had at least one lung transplanted (p=0.71), while 6.5% and 5.1% had at least one lung discarded (p < 0.001).

Conclusion: Increasing time from donor consent to cross clamp is associated with greater thoracic organ recovery and utilization, and decreased organ discard. This suggests that prolonged lung and heart fluid resuscitation prior to cross clamp may not negatively impact organ viability. Further research is necessary to explore the impact of consent to clamp time on post-transplant outcomes.

Identify the source of the funding for this research project: This work was supported by the Pozefsky Scholars Program.