title: Perioperative extracorporeal membrane oxygenation bridging in patients undergoing pulmonary endarterectomy.
abstract: OBJECTIVE
  Chronic thromboembolic pulmonary hypertension is the only curable form of pulmonary arterial hypertension. Pulmonary endarterectomy (PEA) has been established as the treatment of choice in these patients producing very satisfying results. Some patients develop severe cardiorespiratory decompensation before PEA or during weaning from cardiopulmonary bypass. This might be due to acute reperfusion oedema and/or right ventricular failure caused by residual hypertension. Extracorporeal membrane oxygenation (ECMO) support has been established as a bridging therapy in cardiorespiratory failure. At our department, we used peripheral veno-arterial ECMO in patients deteriorating before PEA and in patients where weaning from cardiopulmonary bypass was not possible.
  
  
  METHODS
  We conducted a retrospective analysis of all the patients undergoing PEA who needed pre- and/or postoperative veno-arterial ECMO support. Outcomes including survival, morbidity and haemodynamic improvement were compared between patients surviving and non-surviving after ECMO support. Further, we analysed survival and risk factors of patients requiring ECMO versus patients without ECMO support.
  
  
  RESULTS
  Between January 2001 and March 2013, a total of 161 patients underwent PEA at our institution. Thirty-one patients (19.3%) required support with peripheral veno-arterial ECMO, either both, pre- and postoperatively (n = 2), or only postoperatively (n = 29). Twenty-eight patients received ECMO directly in the theatre and 1 patient received ECMO at the ICU after successful weaning from cardiopulmonary bypass after PEA. Twenty-eight patients (90.3%) were successfully weaned from ECMO and 20 patients left the hospital alive giving a salvage rate of 64.5%. For those not requiring ECMO support, in-house mortality was 3.1% (n = 4). In the 3 patients where weaning from ECMO was not possible, lung transplantation was performed as a rescue therapy. Long-term survival in the patients requiring ECMO who survived was worse than survival in the non-ECMO patient group. The only significant risk factor for the use of ECMO was a pulmonary vascular resistance higher than 1000 dynes cm s(-5).
  
  
  CONCLUSIONS
  Pre- and postoperative ECMO bridging in patients undergoing PEA is a feasible option to stabilize patients in a critical pre- and/or postoperative situation and to improve outcome in these patients who would otherwise probably not survive the procedure.
authors.affiliation: Division of Thoracic Surgery, Department of Surgery, Medical University of Vienna, Vienna General Hospital, Vienna, Austria patrick.nierlich@meduniwien.ac.at.
authors.forename: Patrick
authors.initials: P
authors.lastname: Nierlich
authors.affiliation: Department of Medical Statistics, Medical University of Vienna, Vienna General Hospital, Vienna, Austria.
authors.forename: Robin
authors.initials: R
authors.lastname: Ristl
mesh_terms: D001317:Austria / Q000453:epidemiology; D004691:Endarterectomy / Q000379:methods*; D015199:Extracorporeal Membrane Oxygenation / Q000379:methods*; D005260:Female; D017052:Hospital Mortality / Q000639:trends; D006801:Humans; D006976:Hypertension, Pulmonary / Q000209:etiology / Q000401:mortality / Q000503:physiopathology / Q000601:surgery*; D016040:Lung Transplantation; D008297:Male; D008875:Middle Aged; D019990:Perioperative Care / Q000379:methods*; D011651:Pulmonary Artery / Q000503:physiopathology / Q000601:surgery*; D011655:Pulmonary Embolism / Q000150:complications / Q000401:mortality / Q000601:surgery*; D012189:Retrospective Studies; D012307:Risk Factors; D015996:Survival Rate / Q000639:trends; D016896:Treatment Outcome; D014655:Vascular Resistance
keywords: Chronic thromboembolic pulmonary hypertension; Extracorporeal membrane oxygenation; Pulmonary endarterectomy; Pulmonary hypertension