Not All Lungs are Dirty: Positive Sputum Culture in a Candidate with Pulmonary Fibrosis (PF) Should Not Always Deny the Option of Single Lung Transplant

Abstract

Purpose Studies have shown that bilateral lung transplants (BLT) confer a better 5-year survival compared to single lung transplants (SLT). Many PF patients without pulmonary hypertension (PH) are listed because of positive sputum cultures, however, as PF is not a septic disease, SLT may be a viable option. 65 patients died on the UK waiting list in 2017 with highest mortality in the PF group. Our aim is to determine if more patients with PF could be listed for SLT, from a review of respiratory cultures at the time of explant and post-transplant pulmonary infections, in patients that underwent BLT based on their pre-op respiratory cultures. Methods We identified patients who underwent BLT or SLT for PF over a 10-year period (2006-2016). We studied pre-op sputum cultures, bronchoalveolar lavages (BAL) of the recipient lung performed at the time of explant and BALs up to 12 months post transplant. Results 53 patients underwent BLT; a control group of 56 underwent SLT in the same period . The BLT group was subdivided into patients with positive pre-op sputum (Group A, n=23) and negative pre-op sputum (Group B, n=30). In Group A, 13/23 patients (56.5%) were listed for BLT only. 10/13 patients were listed for BLT on the basis of positive sputum results. Of these, 8/10 had no growth at the time of explant BAL. Seven out of 23 patients (30.4%) were listed for either SLT or BLT. Overall, 21/23 patients (91.3%) had no growth at the time of explant BAL. The percentage of positive BALs up to 12 months post-transplant was 33%. In Group B, 20/30 patients (66.7%) were listed for either BLT or SLT; while 3/30 (10%) were listed for BLT. All the patients (100%) had no growth at the time of explant BAL. The percentage of positive BALs in Group B was 37.3%. In the control group (SLT), 26/56 patients (46.4%) had no growth, while 20 did not produce any sputum. Only 9/56 patients (16.1%) had positive sputum pre-op - none grew any organisms at the explant BAL. Overall, only 3/56 patients (5.3%) grew organisms at the time of explant BAL. Conclusion The majority of patients who had BLT on the basis of positive microbiology had no growth at the time of explant BAL. In addition, they had a similar rate of post-operative positive BALs out to 12 months. From this analysis, more patients will benefit from being listed for either BLT or SLT, a step which may reduce both waiting times and waiting list mortality.