Telemedicine with a Cell-Free DNA Based Monitoring Approach Maintains Lung Allograft Function While Reducing Frequency of Invasive Bronchoscopy

Abstract

Purpose The need to reduce in-person clinic visits during the COVID-19 pandemic necessitated a significant reduction in traditional lung transplant surveillance with bronchoscopy and clinic-based pulmonary function testing (PFT). We hypothesized that a screening strategy that utilized cell free DNA (CareDx: Allosure), a non-invasive marker of molecular allograft injury, to determine the need for for-cause diagnostics would yield equivalent lung function stability as traditional monitoring using surveillance bronchoscopy and clinic performed PFTs in lung transplant recipients. Methods We compared the change in FEV1, the prevalence of donor-specific HLA antibodies (DSA), and frequency of hospitalization over parallel 6-month timespans in 2 cohorts of LTRs assessed during the 1st 3 years of their transplant. The 1st cohort (N=65) was monitored from 3/2019 to 9/2019 by in-clinic PFT, surveillance bronchoscopy, DSA, and the 2nd cohort (N=73) was monitored from 3/2020-9/2020 with telemedicine, home spirometry, surveillance dd-cfDNA, and DSA testing every 1-3 months. In cohort 2, patients with >10% decline in home FEV1, and/or dd-cfDNA>1% underwent for-cause bronchoscopy and/or further diagnostic evaluation. Surveillance PFTs were conducted once between 7/20 and 9/20 in cohort 2 to assess the stability of lung function. For both cohorts, a minimum interval of 150 days and a maximum interval of 200 days was used for analysis of spirometric change. Results There were significantly fewer bronchoscopies/patient (pt) in cohort 2 vs cohort 1 (0.91 vs 1.8, p Conclusion The use of non-invasive cell-free DNA testing with home spirometry screening appears to yield comparable medium-term allograft outcomes, as compared to conventional clinic-based PFTs and surveillance bronchoscopy. Further multi-center studies are warranted to determine if this approach can reduce invasive procedures while maintaining equivalent outcomes in clinically meaningful parameters.