Surgical treatment for aneurysms of the descending aorta using temporary perfusion by a centrifugal pump: clinical analysis of 33 cases

Antifibrinolytic Use and Bleeding During Surgery on the Descending Thoracic Aorta: A Multivariate Analysis

OBJECTIVES

The purpose of this study was to determine the potential benefit of antifibrinolytic (AF) therapy in improving hemostasis in descending aortic surgery in which extracorporeal distal perfusion is used.

DESIGN

Retrospective database study.

SETTING

University hospital.

PARTICIPANTS

Seventy-two patients who underwent descending thoracic or thoracoabdominal aortic replacement during the period from January 1993 through December 1996 when the use of AF therapy was emerging.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Seventy-two records met criteria for inclusion. The use of AF therapy had no significant effect on any bleeding or transfusion outcome in any model. Excessive chest tube drainage postoperatively was independently associated with repeat surgery and intraoperative hypothermia. The risk of receiving a red blood cell (RBC) transfusion was independently predicted by low preoperative hemoglobin and age > or =65 years. Cross-clamp was an independent predictor of receiving a transfusion of non-RBC products (p = 0.03).

CONCLUSIONS

The authors could not show a beneficial effect of AF therapy on bleeding and transfusion, although current practice shows that this therapy continues to be used. Because heterogeneity of patient population exists and bias cannot be completely excluded, a prospective investigation evaluating efficacy and safety in this population is warranted.

Perioperative management of calves undergoing implantation of a left ventricular assist device

OBJECTIVE

To describe perioperative management of calves that underwent left lateral thoracotomy, aortic cross-clamping, partial left heart bypass and implantation of a left ventricular assist device.

SAMPLE POPULATION

A total of 43 healthy castrated male calves, weighing 121 +/- 24 kg.

RESULTS

Diazepam (mean +/- SD, 0.26 +/- 0.07 mg/kg), ketamine (5.9 +/- 2.17 mg/kg) and isoflurane were used in the anesthetic management of calves undergoing implantation of a left ventricular assist device in the descending thoracic aorta. Other adjunctive agents administered were fentanyl (11 +/- 5.4 microg/kg), lidocaine (4.9 +/- 3.19 mg/kg), bupivacaine (0.75%) and butorphanol (0.49 +/- 0.13 mg/kg). None of the calves regurgitated at induction or during intubation. A tube was used to drain the rumen and prevent bloat during the procedure. Partial left heart bypass was used to perfuse the caudal half of the body during the period of aortic cross clamp and device implantation. Initial mean systemic blood pressure was 96 +/- 25 mm Hg, and pressures measured in the auricular artery increased during aortic cross-clamping and bypass. Vasoconstrictor therapy was required to treat caudal arterial hypotension during the procedure in 9 calves. Mean systemic arterial pressures returned to baseline values by the end of the anesthetic period. Initial mean pulmonary arterial pressures (PAP) were 22 +/- 3 mm Hg. A significant but transient increase in pulmonary arterial pressure occurred after both heparin and protamine administration.

CONCLUSIONS

The described anesthetic protocol was effective for thoracotomy and implantation of an intra-aortic left ventricular assist device in normal calves. Partial left ventricular bypass was a useful adjunct during the period of aortic cross clamp. The doses of heparin and protamine administered were effective. Responsibility to monitor oxygenation of the cranial half of the animal continues during the bypass period as hypoxemia due to pulmonary dysfunction will not be detected by the perfusionist.

Experimental studies on three types of heparin-coated cardiopulmonary bypass circuits

In cardiovascular operations, we have usually used heparin-coated cardiopulmonary bypass circuits with low systemic heparinization. Three types of heparin-coated cardiopulmonary bypass circuits are available in Japan: 2 of the 3 have covalent heparin bonding, and the other has ionic heparin bonding. We studied these circuits in ex vivo experiments to explore which were the best in terms of biocompatibility. In this study we compared the Carmeda system (Medtronic) and the Capiox system (Terumo) with covalent heparin bonding, and the Duraflo-II (Baxter) with ionic heparin bonding, evaluating them in ex vivo experiments. They were primed with fresh human blood, and we studied and compared the platelet counts, fibrinogen, D-dimmer, beta-thioguanine (TG), thrombin-antithrombin complex (TAT), and C3a and C4a of each of them. Additional research will be presented in the future.