Extracorporeal membrane oxygenation as a bridge to lung transplantation in a patient with persistent severe porto-pulmonary arterial hypertension following liver transplantation.

Idiopathic pulmonary artery hypertension (IPAH) is a progressive disease with a dismal prognosis and lung transplantation is often the only option for patients, who do not respond to pharmacological therapy. We report the use of an extracorporeal membrane oxygenation (ECMO) system in a 49-year-old woman with primary pulmonary hypertension, previously liver transplanted. The patient, listed for lung transplantation, developed respiratory and circulatory failure despite maximal pharmacological therapy and was successfully bridged to emergent bilateral lung transplantation with veno-arterial ECMO. Emergent veno-arterial ECMO was able to rescue the patient and bridge her to bilateral lung transplantation and should therefore be an option for patients with PAH and circulatory collapse.

Does pretransplant left ventricular assist device therapy improve results after heart transplantation in patients with elevated pulmonary vascular resistance?

OBJECTIVE: Pulmonary hypertension (PH), defined as a pulmonary vascular resistance (PVR) >2.5 Wood units (WU) and (or) a transpulmonary gradient (TPG) >12 mmHg, is an established risk factor for mortality in heart transplantation. Elevated PVR in heart transplant candidates can be reduced using a left ventricular assist device (LVAD), and LVAD is proposed to be the treatment of choice for candidates with PH. We analyzed the effect on PVR of pretransplant LVAD therapy in patients with PH and compared posttransplant outcome with matched controls. Long-term survival was compared between heart transplant recipients with mild, moderate or severe PH and patients with no PH. METHODS: Heart transplant recipients 1988-2007 (n=405) were reviewed and divided into two groups with respect to pretransplant PVR: <2.5 WU (n=148) and >2.5 WU (n=158). From the group with PH, patients subjected to pretransplant LVAD therapy (n=11) were analyzed with respect to PVR at implant and at transplant and, with respect to outcome, compared to matched historical controls (n=22). Patients with PH without LVAD treatment (n=147) were stratified into three subgroups: mild, moderate and severe PH and survival according to Kaplan-Meier was analyzed and compared to patients with no PH. RESULTS: LVAD therapy reduced PVR from 4.3+/-1.6 to 2.0+/-0.6 WU, p<0.05. Three cases of perioperative heart failure required mechanical support whereas one control patient developed perioperative right heart failure requiring mechanical support. The incidence of other perioperative complications was comparable between groups. There was no difference in survival between LVAD patients and controls, 30-day survival was 82% and 91%, respectively and 4-year survival was 64% and 82%, respectively. CONCLUSIONS: Pretransplant LVAD therapy reduces an elevated PVR in heart transplant recipients, but there was no statistically significant difference in posttransplant survival in patients with PH with, or without LVAD therapy. The study revealed no differences in survival in patients regardless of the severity of the PH.

Ex vivo evaluation of nonacceptable donor lungs.

BACKGROUND: Only a minority of the potential candidates for lung donation are considered suitable, using current evaluation methods. A new method for ex vivo evaluation, with the potential for reconditioning of marginal and nonacceptable lungs, has been developed. This is a report of the ex vivo evaluation of six donor lungs deemed nonacceptable (arterial oxygen pressure less than 40 kPa) by the Scandiatransplant, Eurotransplant, and UK transplant organizations. METHODS: The lungs are perfused ex vivo with Steen solution, a lung evaluation-preservation solution, mixed with red blood cells to a hematocrit of 15%. This extracellular solution is designed to have an optimal colloid osmotic pressure so that physiologic pressure and flow can be maintained without development of pulmonary edema. An oxygenator connected to the extracorporeal circuit maintains a normal mixed venous blood gas level in the perfusate. The lungs are ventilated and evaluated through analyses of pulmonary vascular resistance, oxygenation capacity, and arterial carbon dioxide pressure minus end-tidal carbon dioxide difference. RESULTS: The arterial oxygen pressure (inspired oxygen fraction, 1.0) increased from 27 kPa (range, 17 to 34 kPa) in situ in the organ donor at the referring hospital to 57 kPa (range, 39 to 66 kPa) during the ex vivo evaluation. The pulmonary vascular resistance varied from 3.2 to 5.7 Wood units, and the arterial carbon dioxide pressure minus end-tidal carbon dioxide difference was in the range of 1 to 2.5 kPa. CONCLUSIONS: The arterial oxygen pressure improves significantly in this model. This ex vivo evaluation model is a valuable addition to the armamentarium in finding acceptable lungs in a donor population with inferior arterial oxygen pressure values.