Background: Two types of surface coating for cardiopulmonary bypass (CPB) are used: bioactive (heparin, nitric oxide) and biopassive (albumin, polyethyleneoxide (PEO), phosphorylcholine). When haemocompatible coatings are combined with the separation of pleuro-pericardial aspiration, attenuation of both the coagulation and complement cascades, as well as better platelet preservation, has been demonstrated. This study wants to investigate if the combination of a bioactive with a biopassive coating (unfractionated heparin embedded in a phosphorylcholine matrix) combines the beneficial effects of both approaches.
Materials and methods: Thirty patients undergoing elective CABG were prospectively randomized into two groups of 15 patients. The sole exclusion criterion was an ejection fraction of less than 40%. In the control group (PC), the whole CPB circuit was coated with phosphorylcholine (PC). In the study group (XPC), unfractionated heparin was embedded in the PC matrix of the oxygenator and arterial line filter.
Results: No differences were found for haemolytic index, thrombin-anti-thrombin complex (TAT), IL-6, IL-10 and blood loss. PF4 plasma concentration increased from 27.6±22.0 IU/mL to 165.7±43.9 IU/mL (p<0.001) at 15 minutes of CPB in the PC and from 16.0±9.7 IU/mL to 150.9 ± 61.3 IU/mL (p<0.001) in the XPC group. Terminal complement complex (TCC) increased over time in both groups until the end of CPB (Figure 2A). Within each group, TCC generation was statistically significantly higher after the release of the aortic cross-clamp (p<0.001) and at the end of CPB (p<0.001). Total TCC generation was statistically significantly higher in the XPC group compared to the PC group (p=0.026). The difference was statistically significant after the release of the aortic cross-clamp (p=0.005) and at the end of CPB (p=0.001).
Conclusions: Based on our results, there is no additional benefit in combining phosphorylcholine with unfractionated heparin in elective patients undergoing coronary artery bypass grafting (CABG). Massive haemodilution leads to enhanced complement activation.
CourtneyJMZhaoXBQianHSharmaA. Modification of polymer surfaces: optimization of approaches. Perfusion2003Mar; 18Suppl 1: 33–39.
2.
DanielS. Review on the multifactorial aspects of bioincompatibility in CPB. Perfusion1996 May; 11(3): 246–255.
3.
AldeaGSSoltowLOChandlerWL. Limitation of thrombin generation, platelet activation, and inflammation by elimination of cardiotomy suction in patients undergoing coronary artery bypass grafting treated with heparin-bonded circuits. J Thorac Cardiovasc Surg2002Apr; 123(4): 742–755.
4.
De SomerFVan BelleghaemYCaesF. Tissue factor as the main activator of the coagulation system during cardiopulmonary bypass. J Thorac Cardiovasc Surg2002May; 123(5): 951–958.
5.
De SomerFVan BelleghemYCaesF. Phosphorylcholine coating offers natural platelet preservation during cardiopulmonary bypass. Perfusion2002Jan; 17(1): 39–44.
6.
RotherRPBellLHillmenPGladwinMT. The clinical sequelae of intravascular haemolysis and extracellular plasma haemoglobin: a novel mechanism of human disease. JAMA2005Apr6; 293(13): 1653–1662.
7.
MinneciPCDeansKJZhiH. Haemolysis-associated endothelial dysfunction mediated by accelerated NO inactivation by decompartmentalized oxyhaemoglobin. J Clin Invest2005Dec; 115(12): 3409–3417.
8.
DayJRLandisRCTaylorKM. Aprotinin and the protease-activated receptor 1 thrombin receptor: antithrombosis, inflammation, and stroke reduction. Semin Cardiothorac Vasc Anesth. 2006Jun; 10(2):132–142.
9.
DayJRTaylorKMLidingtonEA. Aprotinin inhibits proinflammatory activation of endothelial cells by thrombin through the protease-activated receptor 1. J Thorac Cardiovasc Surg2006Jan; 131(1): 21–27.
10.
GongJLarssonREkdahlKNMollnesTENilssonUNilssonB. Tubing loops as a model for cardiopulmonary bypass circuits: both the biomaterial and the blood-gas phase interfaces induce complement activation in an in vitro model. J Clin Immunol1996Jul; 16(4): 222–229.
11.
HabibRHZachariasASchwannTA. Role of hemodilutional anemia and transfusion during cardiopulmonary bypass in renal injury after coronary revascularization: implications on operative outcome. Crit Care Med2005Aug; 33(8): 1749–1756.
12.
HabibRHZachariasASchwannTARiordanCJ. The independent effects of cardiopulmonary bypass hemodilutional anemia and transfusions on CABG outcomes. Eur J Cardiothorac Surg2005Sep; 28(3): 512–513; author reply 513–514.
13.
HabibRHZachariasASchwannTARiordanCJDurhamSJShahA. Adverse effects of low haematocrit during cardiopulmonary bypass in the adult: should current practice be changed?J Thorac Cardiovasc Surg2003Jun; 125(6): 1438–1450.
14.
KarkoutiKBeattieWSWijeysunderaDN. Haemodilution during cardiopulmonary bypass is an independent risk factor for acute renal failure in adult cardiac surgery. J Thorac Cardiovasc Surg2005Feb; 129(2): 391–400.
15.
KarkoutiKDjaianiGBorgerMA. Low haematocrit during cardiopulmonary bypass is associated with increased risk of perioperative stroke in cardiac surgery. Ann Thorac Surg2005Oct; 80(4): 1381–1387.
16.
HabibRHZachariasASchwannTARiordanCJDurhamSJShahA. Effects of obesity and small body size on operative and long-term outcomes of coronary artery bypass surgery: a propensity-matched analysis. Ann Thorac Surg2005Jun; 79(6): 1976–1986.
17.
HabibRHZachariasASchwannTARiordanCJDurhamSJShahA. Worse early outcomes in women after coronary artery bypass grafting: is it simply a matter of size?J Thorac Cardiovasc Surg2004Sep; 128(3): 487–488; author reply 488.
