P112 Pulmonary function testing (PFTs) as predictors of survival following liver transplantation

<h3>Introduction</h3> Comprehensive pulmonary function tests (PFTs) may be performed ahead of elective listing for liver transplantation. Previous studies have associated restrictive respiratory deficits with prolonged ventilation and length of stay post-transplantation. Data on an association with survival and which individual tests are associated are lacking. We aimed to establish whether pre-transplant PFTs correlated with post-transplant survival. <h3>Methods</h3> Patients undergoing elective first-graft liver transplantation between 2014–01-01 and 2024–01-01 were assessed. Exclusion criteria were acute-on-chronic liver failure (ACLF) or super urgent listing, second or subsequent liver transplantation, multi-organ transplantation, and transplantation at external centres. Electronic health records were retrospectively analysed for demographics, disease aetiology, investigations including PFTs and outcome data. Where multiple PFT measurements per patient were available, those closest to transplant were analysed. Statistical analysis was conducted using single and multivariable Cox proportional hazards regression models using R. <h3>Results</h3> 1088 patients who underwent liver transplantation were assessed; 258 met exclusion criteria. 72% of the remaining cohort had pre-transplant PFT data available for analysis (n=596). 56% were male (n=390), median age at transplantation was 57 years (IQR 49–63) and median FEV1 2.77L (range 0.87–5.14). 76 patients died, with median time from transplantation to death of 989 days (396–1651). Major primary indications for transplantation were alcohol-related liver disease (ArLD, n=167), metabolic-dysfunction associated steatotic liver disease (MASLD, n=115) and hepatocellular carcinoma (n=101). Current (n=65) and former smokers (n=254) trended to reduced medium and long-term survival compared to never-smokers (n=277), though not at statistical significance including after adjustment for age, sex, BMI and primary aetiology. Both forced expiratory volume (FEV1, HR=0.68, CI=0.47–0.98, p=0.040) and single breath diffusing capacity for carbon monoxide (DLCO_SB, HR=0.83 CI=0.71–0.97, p=0.020) were significantly associated with post-transplant survival considering the same covariables; other commonly measured pre-transplant PFT variables including forced vital capacity, vital capacity, tidal volume and total lung capacity had no significant relationship with post-transplant survival. Neither FEV1 nor DLCO_SB was associated with 1-year survival by univariable or multivariable analysis. <h3>Discussion</h3> Although routine practice, most PFT variables were not strong predictors of post-transplant survival; FEV1 and DLCO_SB were associated with late but not early survival. Focus on investigative variables which significantly predicted post-transplant survival such as FEV1 and DLCO_SB, may help risk stratify patients more effectively, and reduce the burden of wider PFT testing. Larger, multi-centre analysis of more extensive outcome measures including intensive care related events, is required. <h3>Reference</h3> Kia L, Cuttica MJ, Yang A, Donnan EN, Whitsett M, Singhvi A, Lemmer A, Levitsky J. The utility of pulmonary function testing in predicting outcomes following liver transplantation. <i>Liver Transplantation</i>. 2016 Jun;<b>22</b>(6):805–11.