Purpose
The use of cardiopulmonary bypass (CPB) during lung transplantation (LTx) has been linked to higher rates of primary graft dysfunction (PGD) and worse postoperative outcomes. However, the effect of the duration of CPB has not been examined yet. Thus, the aim of our study was to examine the effect of CPB duration on rates of PGD and survival.
Methods
A retrospective cohort study was performed from a prospective database of adult LTx procedures performed at our institute from 1/2008 to 7/2018 (n = 1039). CPB was utilized in 67% of these procedures. Logistic regression fit model was utilized for univariate analysis of PGD at 72 hours. Nonlinear cumulative logistic mixed model was used in analysis of time related PGD grades and the associated risk factors. The survival rates were evaluated by Kaplan-Meier survival -estimate.
Results
Longer duration of CPB was found to be an independent risk factor for severe PGD (Odds ratio, 1.0 per 1 minute increase in CPB duration; P < 0.001). Patients with higher grades of PGD at 72 hours had a significantly longer duration of CPB (Median, 169, 180, 200, and 233 minutes for PGD0, PGD1, PGD2, and PGD3, respectively; P < 0.001, Figure 1A). The incidence of severe PGD at 0, 24, 48, and 72 hours post-LTx were comparable in patients with no CPB and CPB ≤3 hours (16%, 9%, 8%, and 8% vs 26%, 11%, 10%, and 10%, respectively) but these incidences were doubled in patients with CPB > 3 hours (55%, 26%, 25%, and 24%, respectively, Figure 1B). Patients with CPB >3 hours had the lowest 1-year survival rates compared with CPB ≤3 hours and no CPB patients (83%, 89% and 90%, respectively; log-rank P = 0.018).
Conclusion
Analysis of more than 1000 LTx data has shown that longer duration of CPB (>3 hours) is associated with severe PGD and worse survival, while shorter duration of CPB (≤3 hours) and no CPB outcomes remain comparable. These results suggest that duration of CPB is more important rather than using CPB itself. Future studies investigating CPB in LTx should consider the duration as an important factor that might affect results.