Perfusion Techniques For Pulmonary Thromboendarterectomy Under Deep Hypothermia Circulatory Arrest: A Case Series
Background: Pulmonary thromboendarterectomy (PTE) is a complicated surgical procedure that is an effective treatment in reducing pulmonary artery pressure and pulmonary vascular resistance for chronic thromboembolic pulmonary hypertension. Chronic thromboembolic pulmonary hypertension usually results from incomplete lysis of a large organized thrombus in the main pulmonary artery and secondary branches, leading to pulmonary hypertension, right ventricular failure, and subsequent death because of heart failure.
Methods: Between March 1997 and April 2005, 30 PTE operations were performed in Fuwai Hospital, Beijing, China. They were 24 men and 6 women, with an average age of 45.7 +/- 11.4 years and average disease history of 48 +/- 12.6 months. Twelve of them were in New York Heart Association (NYHA) class 4, and 18 were in class 3. Seventeen cases were found with deep venous thrombosis (DVT), and inferior vena cava filters were implanted before surgery.
Results: The mean systolic pulmonary pressure was 91.4 +/- 22.4 mmHg, mean pressure of arterial oxygen (PaO2) was 56.2 +/- 8.6 mmHg, mean cardiac index (CI) was 1.64 +/- 0.47 L/min/m2, and mean saturation of arterial oxygen (SaO2) was 0.90 +/- 0.05. All operations were performed using the PTE procedure under deep hypothermia and intermittent circulation arrest. Perfusion management consisted of myocardial, cerebral protection, lung protection, and deep hypothermia with multiple periods of circulatory arrest and reperfusion at hypothermia, ultrafiltration, and cell-saving techniques. One patient died of infective shock post-operatively. Four cases experienced complications of the central nervous system. The mean cardiopulmonary bypass time was 191.1 +/- 34.4 minutes, the mean aortic clamping time was 95.1 +/- 27.8 minutes, and mean circulation arrest time was 47.7 +/- 12.9 minutes. Improvement of hemodynamic status occurred immediately after surgery. Mean pulmonary artery pressure decreased from 91.4 +/- 22.4 to 48.3 +/- 10.7 mmHg, and CI increased from 1.64 +/- 0.47 to 2.58 +/- 0.51 L/min/ m2. PaO2 increased from 56.2 +/- 8.6 to 88.9 +/- 6.0 mmHg and SaO2 increased from 0.90 +/- 0.05 to 0.97 +/- 0.01.
Conclusion: Twenty-six cases were followed for 36.8 months: 22 in NYHA class 1, 3 in class 2, and 1 in class 3. PTE is an effective treatment for chronic thromboembolic pulmonary hypertension. The key to success is to adopt synthesized measures to protect the vital organ under deep hypothermic circulatory arrest (DHCA) from ischemia and reperfusion injury. Appropriate patient selection, perioperative management, improved techniques, and experience can optimize outcome.
