Alternatives to Heparin for Extracorporeal Membrane Oxygenation
One of the most promising medical advances of recent times has been extracorporeal membrane oxygenation. However, its use has been severely limited by the need to use heparin to avoid coagulation. There are now a number of possible alternatives which would permit safe long term ECMO use.
One possibility would be to use cloned vascular endothelial cells. The cells, suspended in their culture medium, could be instilled into the devices where over a few hours they would coat their surfaces and begin to grow to form a continuous biologically compatible lining.
An alternative approach would be to selectively disable coagulation. One approach would be to disable the intrinsic pathway while leaving the extrinsic pathway intact as is the case in hemophilia. This was accomplished by Ellinor Kenne and,Thomas Renné through the use of factor XIIa neutralizing antibody,[Drug Discovery Today
Volume 19, Issue 9, September 2014, Pages 1459-1464].
Yet another possibility would be adding nitric oxide to the oxygen in the oxygenator to block platelet aggregation. A nitric oxide oxidase such as myeloperoxidase could also be added in order to avoid systemic effects such as vasodilation. The input and output tubes could be lined with soft open cell plastic foam surrounding permeable membrane similar to that of the oxygenator. Nitric oxide could be permeated and diffused therein. This is, of course, all theoretical. Nonetheless, it is theory worth exploring.