Tales of the Unexpected: Donor Lung with CTEPH, a Unique Case Report

Abstract

<h3>Introduction</h3> Whilst chronic thromboembolic pulmonary hypertension (CTEPH) is a recognised indication for lung transplantation, it is an undesirable finding in a lung donor. We present the case of an individual who underwent a single lung transplant with an allograft that was subsequently identified as having CTEPH. <h3>Case Report</h3> This 65 year old, 167cm, blood group A RhD+ female with fibrotic organising pneumonia was listed for a left single lung transplant on the basis of a hypokinetic right hemi-diaphragm. She received an organ from a 55year old, 159cm, blood group A RhD+, non-smoking female DBD donor, who died from a subarachnoid haemorrhage. The donor had possible asthma (not formally diagnosed) and an unenhanced CT chest demonstrated non-specific mosaic attenuation. A donor echocardiogram showed mild tricuspid regurgitation with normal right ventricular (RV) size but impaired radial systolic function. Donor blood gases on FiO₂ 1.0 demonstrated PaO₂ 35kPA in the left upper lobe and 64kPa in the left lower lobe pulmonary veins. The recipient surgery was uneventful, although she developed primary graft dysfunction with RV impairment. She was stabilised and extubated after 24 hours onto 2L/min supplemental oxygen. Day 10 post-transplant she developed increasing oxygen requirements. CT pulmonary angiography demonstrated patent vascular anastomoses, left lower lobe pulmonary artery occlusion and features of CTEPH, but no lung necrosis. A right heart catheter study confirmed mild pulmonary hypertension with a mean pulmonary artery pressure 25mmHg and pulmonary vascular resistance 6 Wood Units. She underwent pulmonary endarterectomy (PEA) with good clearance of the donor vasculature. She weaned easily from cardiopulmonary bypass and her supplemental oxygen was down-titrated. She was discharged home 6 weeks post-transplant to complete 12 weeks of anticoagulation. 5 months post-transplant she developed fever and hypoxia with imaging features of left lower lobe consolidation, but no new thrombus. In the context of poor physiological reserve, the patient and family requested palliation. <h3>Summary</h3> CTEPH is rare in the general population, with a prevalence 3-30 per million. In this case, the diagnosis of CTEPH only came to light after transplantation and this is the first report of PEA performed in a lung recipient. Transplant teams should be alert for CTEPH in potential lung donors.