The current surgical technique for pulmonary endarterectomy (PEA) involves the use of deep hypothermia and circulatory arrest at 18 degrees C (DHCA). Our experience started in 2004 when we decided to use an original alternative strategy which consists of avoiding deep hypothermia and subsequent circulatory arrest by using moderate hypothermia at 26 degrees C, and maintaining a bloodless field. This can be achieved by means of negative pressure in the left heart chambers and appropriate pump flow modulation in order to maintain the mixed venous oxygen saturation (SVO(2)) higher than 65%.From June 2004 to June 2007, 40 consecutive patients were operated on in our department with this strategy. The aim of this article is to report the early results for all patients and the complete six-month follow-up for 30 subjects who have reached this end-point at the time of writing. The mean temperature during extracorporeal circulation was 25.9 degrees C; core temperature was lowered to 21 degrees C in only one patient and an 8 min DHCA was performed in order to complete the PEA.Two patients died (6.6%): one on the third postoperative day due to myocardial infarct, requiring an ECMO implantation. The other patient died from septic shock. The six-month follow-up, performed in all other patients, included clinical and hemodynamic evaluation. Pulmonary vascular resistance (PVR) decreased from 793.5+/-284 dyn/cm/s(-5) to 286+/-143 (p=0.000). A comparable reduction of mean pulmonary arterial pressure and an increase of cardiac output were also observed.The results confirm that adequate removal of pulmonary artery obstructive lesions can also be achieved with an operative procedure that avoids or reduces the use of DHCA while allowing a bloodless field during PEA interventions. This technique may limit the well known adverse effects of DHCA due to organ hypoperfusion, improving the postoperative recovery of the patients.