A Nitric Oxide Releasing, Gel-Coated Oxygenator Significantly Reduces Clot Formation and Thromboembolic Events in a Mouse Model of Veno-Arterial Extracorporeal Membrane Oxygenation

All articles of this category (opens in new window) Background: Oxygenator thrombosis remains a life-threatening complication for patients treated with ECMO. Various studies have been conducted to improve the biocompatibility of oxygenator membranes using special coatings or endothelialization approaches. Nitric oxide (NO) is known for its antithrombotic activity, through blocking NET formation via NO/cGMP signaling, thereby abolishing platelet activation and aggregation. The aim of our study was to investigate the effect of a NO-releasing gel coating on thrombosis formation in a mouse VA ECMO model. Methods: Twelve 16-week-old C57/Bl6 mice were subjected to VA ECMO for 3 hours under heparinisation at a dose of 3 IU/g BW. Monitoring during ECMO included ECG, rectal temperature, novel optometric subcutaneous tissue oxygenation measurement, regular blood gas analysis, and real-time UV light recording on the oxygenator. The control group was subjected to ECMO using standard heparin-coated oxygenators, while the experimental group received the same type of oxygenators but additionally coated with NO-releasing gel. After the experiments, the oxygenators were flushed with saline and fixed in formalin. The heart, lungs, kidneys, and liver were collected and examined using haematoxylin and eosin (H&E) and Carstairs staining techniques in order to evaluate thromboembolic alterations. Results: The average clot formation was reduced by nine times ( p = 0.012) by coating with an NO-releasing gel, compared to the control animals (3.27% /− 0.82% vs. 27.39% /− 13.35% of the oxygenator surface area). Notably, UV camera monitoring revealed accelerated thrombus formation in the control ECMO group. Moreover, the NO gel coating showed a better trend in terms of oxygenation throughout, lower lactate values (5.62 ± 2.25 vs. 10.9 ± 4.7) and a more stable metabolic state (pH 7.33 ± 0.06 vs. 7.13 ± 0.28). Cairstairs staining demonstrated considerably less fibrin accumulation and platelet aggregation, as well as decreased thrombus formation in the lungs, glomeruli, and liver sinusoids in the experimental group, compared to animals subjected to ECMO without a gel coating. Conclusion: Mice subjected to VA ECMO using an NO gel-releasing coating showed ninefold less clotting on the membrane oxygenator, as well as minimal thromboembolic events and reduced inflammation in lung, liver, and kidney tissue. This innovative coating might be a highly promising method of prolonging oxygenator functionality and reducing thromboembolic complications in ECMO. Publication History Article published online: 17 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany