Hypothermic effects on gas exchange performance of membrane oxygenator and blood coagulation during cardiopulmonary bypass in pigs.

INTRODUCTION: Whether hypothermic cardiopulmonary bypass could attenuate both blood coagulation and platelet activation compared to normothermic cardiopulmonary bypass remains elusive. METHODS: Biocompatibility of a polymer-coated cardiopulmonary bypass circuit was comparatively assessed by plasma proteomics between juvenile pigs undergoing hypothermic (23°C) cardiopulmonary bypass and those undergoing normothermic (37°C) cardiopulmonary bypass (n = 6, respectively). Plasma samples were taken three times: 5 minutes after initiation of cardiopulmonary bypass (T5, before cooling), just before declamping and rewarming (Tc), and just before termination of cardiopulmonary bypass (Trw, 120 minutes). Proteomic analysis was quantitively performed by isobaric tags for relative and absolute quantification labeling. Thrombin-antithrombin complexes (TAT III) were measured by enzyme immunoassay, and vitamin K-dependent protein C (PROC), ß-thromboglobulin (TG), and P-selectin were measured by enzyme-linked immunosorbent assay. Blood gas analyses evaluated oxygenator performance. RESULTS: Hypothermic cardiopulmonary bypass had a significantly higher PaO2 at Tc and lower PaCO2 at Trw than normothermic cardiopulmonary bypass. Two hundred twenty-four proteins were identified with statistical criteria of both protein confidence (>95%) and false discovery rate (<5%). Six of these proteins significantly decreased at Tc than at T5 in hypothermic cardiopulmonary bypass (p = 0.02-0.04), with three related to platelet degranulation. Protein C decreased at Trw compared with T5 in normothermic cardiopulmonary bypass (p = 0.04). Thrombin-antithrombin complex had a slightly larger increase with normothermic cardiopulmonary bypass at Trw than with hypothermic cardiopulmonary bypass. ß-thromboglobulin and P-selectin levels were significantly lower at Trw with hypothermic cardiopulmonary bypass than with normothermic cardiopulmonary bypass (p = 0.04). CONCLUSION: Hypothermic cardiopulmonary bypass attenuated platelet degranulation/blood coagulation and maintained better oxygenator performance compared to normothermic cardiopulmonary bypass in juvenile pigs.

Recovery from very long aortic cross-clamping in redo complex aortic surgery.

A 68-year-old man had undergone ascending aortic replacement for acute type A aortic dissection. Three months later, he had a new aortic dissection with an ulcer-like projection located in the aortic arch with suspected graft infection. An emergent redo total aortic arch and root replacement was performed because of the coexistence of a fragile aortic root wall. The extensive redo procedure necessitated a very long aortic cross-clamping time (516 min). After 25 min of assisted circulation, he was easily weaned from the cardiopulmonary bypass. Finally, an omental flap was harvested to cover the graft. Postoperative ECG and CK-MB examinations showed no significant myocardial injury. He had no symptoms of heart failure and was discharged after a month of antibiotic therapy. One-year follow-up UCG study revealed no abnormal findings except for signs of pericardial adhesion.

Polymer-coated cardiopulmonary bypass circuit attenuates upregulation of both proteases/protease inhibitors and platelet degranulation in pigs.

INTRODUCTION: Interaction of blood with a cardiopulmonary bypass (CPB) circuit activates the coagulation-fibrinolysis, complement and kinin-kallikrein systems that are mainly supported by proteases and their inhibitors. METHODS: Biocompatibility of a new polymer-coated (SEC-coated) CPB circuit was globally evaluated and compared with that of a non-coated CPB circuit by quantitative proteomics, using isobaric tags for relative and absolute quantification labeling tandem mass spectrometry. Plasma samples were taken three times (5 min after initiation of CPB, just before declamping and just before termination of CPB) in 12 pigs undergoing 120 min of CPB with the SEC-coated CPB circuit or a non-coated CPB circuit (n = 6, respectively). RESULTS: Identified were 224 proteins having high protein confidence (>99%) and false discovery rate (FDR) <5%. Among these proteins, there were 25 significantly upregulated proteins in the non-coated CPB group compared to those in the SEC-coated CPB group. Dominant protein functions were platelet degranulation, serine-type (cysteine-type) endopeptidase inhibitor activity and serine-type endopeptidase activity in the 25 proteins. Bioinformatics analysis similarly revealed upregulation of proteins belonging to platelet degranulation and negative regulation of endopeptidase activity in the non-coated CPB group; these upregulations were effectively attenuated in the SEC-coated CPB group. CONCLUSION: The new polymer (SEC)-coated CPB circuit effectively attenuated upregulation of proteins compared to the non-coated CPB circuit. These proteins were associated with both proteases/protease inhibitors and platelet degranulation.