Physiological coagulation can be maintained in extracorporeal circulation by means of shed blood separation and coating

Abstract

Objective: Conventional extracorporeal circulation results in an activation of coagulation cascades. Coating of extracorporeal circulation tubes as well as avoidance of shed blood recirculation have been shown to reduce these phenomena. We evaluated a new shed blood separation system (AVANT D 970) utilizing a coated cardiopulmonary bypass tube system (PHISIO).

Methods: Forty patients (62 +/- 10 years) underwent isolated coronary revascularization. Four groups (n = 10/group) were defined: no extracorporeal circulation, conventional uncoated extracorporeal circulation, uncoated extracorporeal circulation with shed blood separation, and coated extracorporeal circulation with shed blood separation. Thrombin-antithrombin complex and free Hb were analyzed and statistically compared.

Results: Conventional extracorporeal circulation exhibited the highest intraoperative activation of coagulation (thrombin-antithrombin complex: extracorporeal circulation, 31.1 +/- 15.8 microg/L; uncoated extracorporeal circulation with shed blood separation, 15.3 +/- 7.8 microg/L; coated extracorporeal circulation with shed blood separation, 8.1 +/- 4.8 microg/L; no extracorporeal circulation, 2.4 +/- 0.6 microg/L; P <.05 extracorporeal circulation vs all others) and red blood cell damage (free Hb: extracorporeal circulation, 16.8 +/- 11.4 micromol/L; uncoated extracorporeal circulation with shed blood separation, 10.3 +/- 3.5 micromol/L; coated extracorporeal circulation with shed blood separation, 6.8 +/- 2.9 micromol/L; no extracorporeal circulation, 3.4 +/- 1.1 micromol/L; P <.05 extracorporeal circulation vs no extracorporeal circulation, coated extracorporeal circulation with shed blood separation). Coated extracorporeal circulation with shed blood separation showed only slight activation and cell trauma, which did not differ significantly from no extracorporeal circulation.

Conclusions: Combination of coating and avoidance of shed blood recirculation maintained physiological coagulation levels and markedly reduced red blood cell trauma in extracorporeal circulation procedures. These combined modalities may therefore offer an alternative for off-pump procedures in patients with contraindications for conventional extracorporeal circulation.