The value of point-of-care tests for the detection of SARS-CoV-2 RNA or antigen in bronchoalveolar lavage fluid.

BACKGROUND: Transmission of SARS-CoV-2 from donor to recipient is a clinically relevant risk for developing severe COVID-19 after lung transplantation (LTx). This risk of iatrogenic transmission can be reduced by timely detection of viral RNA or antigen in samples of bronchoalveolar lavage (BAL) fluid obtained at the time of lung procurement. We aimed to retrospectively evaluate the detection of SARS-CoV-2 RNA or antigen in BAL fluid samples using three point-of-care tests (POCTs). METHODS: BAL fluid samples came from patients hospitalized in an intensive care unit during the COVID-19 pandemic. These pandemic samples were scored as positive or negative for SARS-CoV-2 by a RT-qPCR comparator assay for orf1ab. Three commercially available POCTs were then evaluated: cobas SARS-CoV-2 & Influenza A/B assay with the cobas Liat RT-qPCR system (Roche Diagnostics), ID NOW COVID-19 and COVID-19 2.0 (Abbott), and SARS-CoV-2 Rapid Antigen Test (RAT) (Roche Diagnostics). Samples from the pre-pandemic era served as negative controls. RESULTS: We analyzed a total of 98 BAL fluid samples, each from a different patient: 58 positive pandemic samples (orf1ab Ct<38), 20 putatively negative pandemic samples (orf1ab Ct≥38), and 20 pre-pandemic samples. Univariate logistic regression shows that the probability of detection was highest for cobas Liat, followed by ID NOW, and then RAT. Of clinical relevance, cobas Liat detected SARS-CoV-2 RNA in 30 of the 31 positive pandemic samples that were collected within 10 days after RT-qPCR diagnosis of SARS-CoV-2 infection. None of the 20 pre-pandemic samples had a false-positive result for any POCT. CONCLUSIONS: POCTs enable the detection of SARS-CoV-2 RNA or antigen in BAL fluid samples and may provide additional information to decide if donor lungs are suitable for transplantation. Detection of respiratory pathogens with POCTs at the time of donor lung procurement is a potential strategy to increase safety in LTx by preventing iatrogenic transmission and severe postoperative infections.

Comparing right- versus left-first implantation in off-pump sequential double-lung transplantation: an observational cohort study.

OBJECTIVES: Historically, the perfusion-guided sequence suggests to first transplant the side with lowest lung perfusion. This sequence is thought to limit right ventricular afterload and prevent acute heart failure after first pneumonectomy. As a paradigm shift, we adopted the right-first implantation sequence, irrespective of lung perfusion. The right donor lung generally accommodates a larger proportion of the cardiac output. We hypothesized that the right-first sequence reduces the likelihood of oedema formation in the firstly transplanted graft during second-lung implantation. Our objective was to compare the perfusion-guided and right-first sequence for intraoperative extracorporeal membrane oxygenation (ECMO) need and primary graft dysfunction (PGD). METHODS: A retrospective single-centre cohort study (2008-2021) including double-lung transplant cases (N = 696) started without ECMO was performed. Primary end-points were intraoperative ECMO cannulation and PGD grade 3 (PGD3) at 72 h. Secondary end-points were patient and chronic lung allograft dysfunction-free survival. In cases with native left lung perfusion ≤50% propensity score adjusted comparison of the perfusion-guided and right-first sequence was performed. RESULTS: When left lung perfusion was ≤50%, right-first implantation was done in 219 and left-first in 189 cases. Intraoperative escalation to ECMO support was observed in 10.96% of right-first versus 19.05% of left-first cases (odds ratio 0.448; 95% confidence interval 0.229-0.0.878; P = 0.0193). PGD3 at 72 h was observed in 8.02% of right-first versus 15.64% of left-first cases (0.566; 0.263-1.217; P = 0.1452). Right-first implantation did not affect patient or chronic lung allograft dysfunction-free survival. CONCLUSIONS: The right-first implantation sequence in off-pump double-lung transplantation reduces need for intraoperative ECMO cannulation with a trend towards less PGD grade 3.