Do we need to cool the lung graft after ex vivo lung perfusion? A preliminary study.

Background: After normothermic ex vivo lung perfusion (EVLP), pulmonary grafts are usually flush-cooled and stored on ice until implantation although evidence for this practice lacks. We compared outcomes between 2 post-EVLP preservation strategies in a porcine left single-lung transplantation model.

Material And Methods: After cold flush and 2-h EVLP, donor lungs were prepared and split. In [C], (n = 5) lungs cooled on device to 15°C were preserved in ice-water; in [W] (n = 5), lungs were disconnected from EVLP at 37°C and kept at room temperature. The left lung was transplanted in a recipient animal. Posttransplant, 6 h-monitoring included hourly assessment of pulmonary vascular resistance, pulmonary artery pressure, plateau airway pressure, compliance, and oxygenation before and after exclusion of the right lung. Lung biopsies and bronchoscopy with bronchoalveolar lavage (BAL) were performed at retrieval, at the end of EVLP (R lung), and 1 and 6 h after reperfusion (L lung).

Results: Lungs in [W] showed the highest compliance (P < 0.05) and the lowest plateau airway pressure (not statistically significant) throughout the whole reperfusion period. Oxygenation and pulmonary artery pressure were similar between groups. Pulmonary vascular resistance was stable in [C], but rose after reperfusion in [W]. Histologic signs of lung injury and BAL neutrophilia were more pronounced in [C] at 1 h (not statistically significant and P < 0.05, respectively). BAL cytokine levels and lung tissue expression of intercellular adhesion molecule 1 did not differ between groups.

Conclusions: Normothermic preparation after EVLP results in similar graft performances compared with lung cooling after EVLP.