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Purpose Ex Vivo Lung Perfusion (EVLP) is an excellent method to preserve and recondition donor lungs, thus increasing the lung donor pool. This systematic review summarizes studies comparing both primary graft dysfunction (PGD) and survival between EVLP and conventional lung transplantation (c-LTx), or between different EVLP protocols. The objective is to evaluate outcomes of the three main EVLP protocols: ‘Lund’, ‘Toronto’ and ‘Organ Care System’ (OCS), through a network meta-analysis (NMA). Methods A systematic search was performed in Pubmed, Embase, the Cochrane library and Web of Science. Studies performing EVLP on initially discarded donor lungs were independently assessed for eligibility by two researchers. Data on study design, participants, and EVLP methods were extracted, together with outcomes such as survival and PGD. The generated database was assessed on meeting the assumptions for NMA. Results Nine studies were included: two non-randomised clinical trials (n = 240), and four prospective (n = 1360) and three retrospective observational cohort studies (n = 540). The study protocols could be divided into: Toronto (5/9), Lund (3/9) and OCS (1/9). Most frequently reported outcomes were PGD grade 3 at 72 hours post-LTx, and one-month and one-year survival. All included studies compared EVLP to c-LTx, providing solely indirect evidence for comparison between protocols and thus no loops within the NMA model. In the absence of loops, consistency within the model cannot be statistically assessed. Thus, thorough examination for differences that could modify the treatment effect is required. Substantial variations were found in study design, type of LTx, and participant characteristics. It was therefore not feasible to construct a subset of studies that met the similarity and consistency assumptions of NMA. Conclusion Currently, no substantiated statistical comparison can be made between different EVLP protocols. Further attempts at NMA are dependent on the introduction of studies comparing multiple EVLP protocols, or an increase in randomised controlled trials performing EVLP on standard donor lungs. Alternatively, collaborative data management between EVLP centres would be a promising way to explore the effect of different protocols, and their individual components, on patient outcomes.

Purpose We present a research model that uses abattoir sheep lungs on ex vivo lung perfusion (EVLP). To best draw parallels, an EVLP animal model should be of comparable lung size, structure, circulatory and respiratory function. Especially, PaO2/FiO2, pulmonary artery- and left atrial pressures (PAP and LAP) and airway pressures should meet clinical standards. Methods Contact was made with an abattoir willing to sell animal lungs for research. A faster procurement was negotiated, as well as on-site flushing and sampling. Six lungs from 20-30kg sheep were used. Pig lungs were unusable due to the boiling process they undergo. Sheep were stunned by a captive bolt pistol prior to exsanguination. Lungs were flushed and submerged in Perfadex Plus for 3 (n=4) or 7 hours (n=2) (hrs) of static cold storage (SCS). Each perfusion a home-made set was primed with 1.7L of buffered dextran-albumin solution (BDAs). Low flow (20% cardiac output) and tidal volume (6ml/kg BW) were chosen. Perfusion was run for 3 (n=4) or 7 (n=2) hrs. No extra perfusate was added in the 3hr runs. Lung biopsies, respiratory values, PAP and LAP were recorded and hourly blood gas analyses were performed. Results Mean oxygenation capacity remained stable with 47.1kPa pO2 at 1hr and 47.2kPa pO2 at 3hrs, p = 0.97. Our 7hrs perfusion case also remained stable between the 1st hr (47.8 kPa pO2) and the 7th hr (pO2 45.2 kPa). Furthermore pressures remained adequate both after 3hrs and 7hrs, a PAP ≤ 15 mmHg, LAP 3-5 mmHg and peak pressures ≤ 20 cmH2O. Mean wet weight/dry weight analyses showed an overall increase in oedema, 81.8% at procurement to 86.1% 3hrs post perfusion, p Conclusion Abattoir animal lungs on EVLP are a good source for testing donor lung treatments. Three and 7hrs of SCS, as well as 3 and 7hr perfusions are possible.