Incidental finding of elevated pulmonary arterial pressures during liver transplantation and postoperative pulmonary complications

Background: In patients with end stage liver disease (ESLD) scheduled for liver transplantation (LT), an intraoperative incidental finding of elevated mean pulmonary arterial pressure (mPAP) may be observed. Its association with patient outcome has not been evaluated. We aimed to estimate the effects of an incidental finding of a mPAP > 20 mmHg during LT on the incidence of pulmonary complications.

Methods: We examined all patients who underwent a LT at Paul-Brousse hospital between January 1,2015 and December 31,2020. Those who received: a LT due to acute liver failure, a combined transplantation, or a retransplantation were excluded, as well as patients for whom known porto-pulmonary hypertension was treated before the LT or patients who underwent a LT for other etiologies than ESLD. Using right sided pulmonary artery catheterization measurements made following anesthesia induction, the study cohort was divided into two groups using a mPAP cutoff of 20 mmHg. The primary outcome was a composite of pulmonary complications. Univariate and multivariable logistic regression analyses were performed to identify variables associated with the primary outcome. Sensitivity analyses of multivariable models were also conducted with other mPAP cutoffs (mPAP ≥ 25 mmHg and ≥ 35 mmHg) and even with mPAP as a continuous variable.

Results: Of 942 patients who underwent a LT, 659 met our inclusion criteria. Among them, 446 patients (67.7%) presented with an elevated mPAP (mPAP of 26.4 ± 5.9 mmHg). When adjusted for confounding factors, an elevated mPAP was not associated with a higher risk of pulmonary complications (adjusted OR: 1.16; 95%CI 0.8-1.7), nor with 90 days-mortality or any other complications. In our sensitivity analyses, we observed a lower prevalence of elevated mPAP when increasing thresholds (235 patients (35.7%) had an elevated mPAP when defined as ≥ 25 mmHg and 41 patients (6.2%) had an elevated mPAP when defined as ≥ 35 mmHg). We did not observe consistent association between a mPAP ≥ 25 mmHg or a mPAP ≥ 35 mmHg and our outcomes.

Conclusion: Incidental finding of elevated mPAP was highly prevalent during LT, but it was not associated with a higher risk of postoperative complications.