To investigate whether deep (≪20 °C) hypothermia is necessary in patients undergoing pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension.Methods:
Between January 2004 and February 2005, 30 patients (New York Heart Association (NYHA) class III or IV) were randomly assigned to increasing (1 °C) levels of moderate (28-32°C) hypothermic cardiopulmonary bypass (CPB), each study group including six patients. Primary study endpoint was adverse neurological outcome. Overall preoperative total pulmonary vascular resistance was 1110 ± 192 dyne s cm−5.Results:
Mean CPB and cross-clamp times, and core temperature at the time of circulatory arrests were 129 ± 39 min and 92 ± 24 min, and 30.1 ± 1.5 °C, respectively. Circulatory arrest was induced 2 ± 0.7 times and its mean total duration was 10.3 ± 5.2 min (range, 2-19 min). Postoperatively, three patients (10%) belonging to the 31 °C (n = 1) and 32 °C (n = 2) groups suffered from temporary neurological dysfunction. Postoperative mechanical ventilatory support and ICU stay were 26.3 ± 18.9 h and 6.6 ± 8.5 days, respectively, and uninfluenced by degree of hypothermia. There were no lung reperfusion injuries or any other major complications. All patients had a significant hemodynamic improvement.Conclusion:
Results suggest that pulmonary endarterectomy can be safely performed with moderate hypothermia and short periods of circulatory arrests without the need of profound hypothermia.