PURPOSE: We report our pre-clinical experience with human EVLP to evaluate lungs for transplant suitability.
METHODS: Fifteen human lung blocks rejected for lung transplant (LTX) because of poor oxygenation, purulent secretions, or chest X-ray abnormalities, were retrieved from conventional brain-dead organ donors after cold Perfadex™ flush (Vitrolife, Sweden), stored cold, then perfused and warmed to 37C in a modified cardiopulmonary bypass circuit with Steen solution™ (XVIVO/Vitrolife, Sweden). Steen solution™ was circulated through a membrane oxygenator ventilated with CO2 and nitrogen to deoxygenate it before infusion into the pulmonary artery at 40% predicted cardiac output. Oxygenation, airway pressure, and vascular resistance were assessed hourly for 6 hours or until pulmonary edema occurred. Wet-to-dry ratios (W/D) were calculated from lung biopsies obtained from non-dependent portions of lung pre- and post-EVLP. Bronchoscopy was performed at the beginning of EVLP. After EVLP, lungs were cooled, flushed with cold Perfadex™, and had an ex-vivo spiral computed tomographic (CT) scan. Donor pO2/FiO2 before retrieval was obtained from donor records. Comparisons were made using paired t tests.
RESULTS: Twelve lung blocks underwent EVLP. Two were excluded from analysis: one due to prolonged (5 day) cold storage, and one that was inadvertently flushed with Ringer’s lactate. In the remaining ten, cold ischemic time averaged 1151±91 minutes (mean±SEM). During EVLP, W/D ratio decreased from 6.05 to 5.05 (p<0.05), oxygenation improved - pO2/FiO2 increased from 369 mm Hg after one hour to 436 mm Hg (p<0.10, NS). pO2/FiO2 in the donor (232 mm Hg) increased to 436 mm Hg after EVLP (p<0.001). Peak and mean airway pressures did not change during EVLP. Despite improved and acceptable oxygenation in many lungs, ex-vivo CT scans showed infiltrates or edema in 10 of 12 lung blocks.
CONCLUSIONS: EVLP results in reduced W/D and improved oxygenation. EVLP, coupled with ex-vivo bronchoscopy and CT scan, allows for assessment of transplant suitability.
CLINICAL IMPLICATIONS: EVLP will allow salvage of some lungs turned down for transplant from conventional brain-dead organ donors, and assessment of lungs retrieved after death from non-heart-beating donors. Thus, EVLP may greatly expand the number of suitable lungs for transplantation.
DISCLOSURE: Thomas Egan: Other: donations-in-kind in support of research from XVIVO/Vitrolife
The following authors have nothing to disclose: Boming Dong, John Blackwell, Will Simmons, Edward Jernigan, William Nicotra, John Haithcock, Ben Haithcock, Zhigang Tian, Shekar Reddy, Katherine Birchard, Paul Stewart, Peadar Noone
The PI/presenter has an IDE from the FDA for use of Steen solution provided by XVIVO/Vitrolife so that lungs undergoing ex-vivo perfusion can be transplanted into consented patients. Steen solution is not yet FDA-approved for use in the US.