REPERFUSION INJURY IN SINGLE-LUNG TRANSPLANT RECIPIENTS WITH PULMONARY-HYPERTENSION AND EMPHYSEMA

Background: The early postoperative course of single-lung transplant r ecipients depends on the recipient's underlying lung pathophysiology a nd the degree of ischemic-reperfusion injury. We examined the effect o f pulmonary hemodynamics and preoperative diagnosis on early allograft function and the effects of pulmonary hemodynamics, allograft blood f low, and chest radiographs on length of mechanical ventilation and int ensive care unit length of stay. Methods: We retrospectively collected data on 30 single-lung transplant recipients, 15 each with pretranspl antation pulmonary hypertension and emphysema. Blood flow to the allog rafts was quantitated by perfusion scans obtained on the first postope rative day. Chest radiographs were graded for reperfusion injury. Pulm onary and hemodynamic data, gas exchange parameters, duration of mecha nical ventilation, and intensive care unit stay were recorded. Results : Patients with pulmonary hypertension had a prolonged intensive care unit stay compared with emphysema patients, but pulmonary artery press ures were not quantitatively related to duration of ventilation during the intensive care unit stay. There was no difference in the severity of allograft infiltrate between the emphysema and pulmonary hypertens ive patients. The day 1 chest radiograph score was highly predictive o f an intensive care unit stay of greater than or equal to 7 days, alth ough the threshold score of those with pulmonary hypertension was sign ificantly lower than in emphysema patients. Allograft blood flow and p ulmonary hypertension were not contributors to early graft dysfunction . Allograft perfusion decreased with increasing radiographically demon strated infiltrate in those with emphysema but not in those with pulmo nary hypertension. Conclusions: Elevated allograft blood flow and pres sures do not exacerbate radiographically confirmed reperfusion injury. Reperfusion injury is the major cause of early respiratory morbidity after single-lung transplantation. Allograft perfusion in emphysema pa tients decreases in response to reperfusion injury, but pulmonary hype rtension patients remain almost entirely dependent on allograft functi on, even with severe chest radiograph scores. This may be an important mechanism by which single-lung transplant recipients with emphysema, unlike those with pulmonary hypertension, are able to mitigate the deg ree of respiratory impairment associated with reperfusion injury.