BACKGROUND/ OBJECTIVE: The continuous interaction of blood with artificial contact surfaces under cardiopulmonary bypass can lead to a substantial damage of blood cells and plasma factors. Surface biopolymers in oxygenation systems can help increasing the hemocompatibility, often combined with anticoagulative agents such as heparin. The poly(2-methoxyethylacrylate) [PMEA] is a new heparin-free polymer. The objective of this experimental study was to evaluate the hemocompatibility of a PMEA-coated oxygenator (Terumo Capiox RX-25) (PTX) under standardized in vitro conditions compared to two ionic-bound and one covalent-bound heparin-coated models. METHOD: Each oxygenator was mounted in a separate standardized closed circulation system. Heparinized (5 IE/mL) fresh human blood from the same donor (hemodilution: Ringer's solution) was used. Circulation time: 120 - 180 min with a flow rate of 4.0 L/min. Blood samplings: at the beginning, 5. min and every 30 min of the circulation. PARAMETERS: platelets, granulocytes, plasma factors (p-selectin, alpha-granulomeres expression, and TAT(III)-complex). After the experiment, oxygenators were dismantled and examined by scanning electron microscopy. RESULTS: All of the oxygenators led to an initial reduction of platelets and granulocytes. PTX had the lowest platelet and granulocyte reduction rates. With a lower p-selectin release compared to covalent-bound heparin-coated oxygenator and higher expression of alpha-granulomeres compared to ionic-bound heparin-coated oxygenators, the results of PTX indicated that a high number of circulating platelets were intact on the PMEA surface. TAT(III)-complex showed a steady increase in all of the oxygenators during the tests, more remarkably in PTX. In contrast to ionic-bound heparin-coated oxygenators, the electron microscopy displayed virtually no cellular accumulation on hollow fiber and housing surfaces of PTX and covalent-bound heparin-coated oxygenator. CONCLUSIONS: 1. The hemocompatibility characteristics of PTX were remarkably better than ionic-bound heparin-coated oxygenators and slightly better than the covalent-bound heparin-coated model under in vitro conditions. 2. The PMEA coating can be a useful alternative for patients with heparin-associated disorders. 3. The clinical feasibility of PTX should be evaluated under in vivo conditions.
BACKGROUND/ OBJECTIVE: The continuous interaction of blood with artificial contact surfaces under cardiopulmonary bypass can lead to a substantial damage of blood cells and plasma factors. Surface biopolymers in oxygenation systems can help increasing the hemocompatibility, often combined with anticoagulative agents such as heparin. The poly(2-methoxyethylacrylate) [PMEA] is a new heparin-free polymer. The objective of this experimental study was to evaluate the hemocompatibility of a PMEA-coated oxygenator (Terumo Capiox RX-25) (PTX) under standardized in vitro conditions compared to two ionic-bound and one covalent-bound heparin-coated models. METHOD: Each oxygenator was mounted in a separate standardized closed circulation system. Heparinized (5 IE/mL) fresh human blood from the same donor (hemodilution: Ringer's solution) was used. Circulation time: 120 - 180 min with a flow rate of 4.0 L/min. Blood samplings: at the beginning, 5. min and every 30 min of the circulation. PARAMETERS: platelets, granulocytes, plasma factors (p-selectin, alpha-granulomeres expression, and TAT(III)-complex). After the experiment, oxygenators were dismantled and examined by scanning electron microscopy. RESULTS: All of the oxygenators led to an initial reduction of platelets and granulocytes. PTX had the lowest platelet and granulocyte reduction rates. With a lower p-selectin release compared to covalent-bound heparin-coated oxygenator and higher expression of alpha-granulomeres compared to ionic-bound heparin-coated oxygenators, the results of PTX indicated that a high number of circulating platelets were intact on the PMEA surface. TAT(III)-complex showed a steady increase in all of the oxygenators during the tests, more remarkably in PTX. In contrast to ionic-bound heparin-coated oxygenators, the electron microscopy displayed virtually no cellular accumulation on hollow fiber and housing surfaces of PTX and covalent-bound heparin-coated oxygenator. CONCLUSIONS: 1. The hemocompatibility characteristics of PTX were remarkably better than ionic-bound heparin-coated oxygenators and slightly better than the covalent-bound heparin-coated model under in vitro conditions. 2. The PMEA coating can be a useful alternative for patients with heparin-associated disorders. 3. The clinical feasibility of PTX should be evaluated under in vivo conditions.
Authors: Angela Paul; Andreas Straub; Norbert Weber; Gerhard Ziemer; Hans Peter Wendel Journal: J Mater Sci Mater Med Date: 2008-09-21 Impact factor: 3.896