Clinical performance and biocompatibility of poly(2-methoxyethylacrylate)-coated extracorporeal circuits

Background. Poly(2-methoxyethylacrylate) is an amphiphilic organic polymer consisting of a hydrophobic backbone with pendant hydrophilic groups that has been reported to reduce protein and platelet adsorption in in vitro and ex vivo studies. Methods. Sixty patients undergoing three-vessel coronary artery bypass grafting were divided into two equal groups. Group 1 had operation with Capiox poly(2-methoxyethylacrylate) coated SX18R oxygenators with noncoated circuits, and group 2 had operation with all noncoated circuits. Hemodynamic variables, blood and urine test results, hematologic variables, complement fractions, C3a and C4d, and interleukin-6 levels were documented preoperatively (T1), on cardiopulmonary bypass (T2), before cessation of cardiopulmonary bypass (T3), after protamine sulfate reversal (T4) and on the first postoperative day (T5). Protein electrophoresis was performed at T1 and T5. Blood cell adhesion and aggregation on fibers were analyzed with optical microscopy, and desorbed protein was evaluated quantitatively by a spectrophotometer using samples obtained when the oxygenators were dismantled after cardiopulmonary bypass. Results. Platelet counts in group 1 demonstrated significant differences at T3, T4, and T5 (p < 0.05) versus group 2 and white blood cell counts in group 1 versus group 2, at counts T4 and T5. Albumin levels were significantly better preserved in group 1 at T4, and T5 and fibrinogen levels, at T3 and T5 (p < 0.05). On electrophoresis, the postoperative albumin level was 57.9% +/- 3% in group 1 versus 50.2% +/- 3% in group 2 (p < 0.05). Postoperative hemorrhage was 452 +/- 35 mL in group 1 and 612 +/- 35 mL in group 2 (p < 0.05). Duration of intubation was significantly lower (p < 0.05) in group 1, as was need of blood transfusion (p < 0.01). More platelet adhesion and aggregation were demonstrated on noncoated oxygenator fibers. The amount of desorbed protein was 0.13 +/- 0.01 mg/dL versus 0.012 +/- 0.001 mg/dL (p < 0.001) on noncoated versus coated fibers, respectively. Conclusions. Poly(2-methoxyethylacrylate)-coated oxygenators reduce platelet adhesion, platelet aggregation and protein adsorption. This surface provides a better perioperative clinical status through platelet-, albumin-, and fibrinogen-sparing effects.