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Updated: Aug 30, 2025
A Microfluidic Flow Chamber Model for Platelet Transfusion and Hemostasis Measures Platelet Deposition and Fibrin Formation in Real-time
Published on: February 14, 2017
In vitro comparison of spatiotemporal fibrin clot formation dynamics in plasma treated with different
Richard Wargowsky1, Jessica Zvara1, Nidal Qaddumi1
1Department of Anesthesiology, George Washington University School of Medicine, Washington, DC, USA.
Introduction:
Our study aim was to explore how different protamine-heparin ratios impacted enzymatic coagulation and acellular fibrin clot growth in plasma using an in vitro model. We hypothesized that a low protamine-heparin ratio would be associated with superior fibrin clot growth dynamics.
Methods:
We performed an in vitro study using 15 plasma samples from a commercial supplier. Different protamine-heparin ratios were added to each donor plasma sample: low ratio (0.7-1), traditional ratio (1-1), and high ratio (1.3-1) and clot formation dynamics were evaluated using a Thrombodynamics analyzer. Study outcomes were initial clot growth velocity and clot size at 30 min.
Results:
Plasma samples treated with a one-to-one protamine-heparin ratio had significantly lower mean initial clot growth velocity compared to samples treated with a low protamine-heparin ratio; mean difference -2.3 μm/min (95% CI = -4.0 to -0.7, p = .004). Plasma samples treated with a one-to-one protamine-heparin ratio also had significantly smaller mean clot size at 30 min compared to samples treated with a low protamine-heparin ratio; mean difference -54.0 μm (95% CI = -107.6 to -0.4, p = .048). There were no significant differences in mean initial clot growth velocity or clot size at 30 min between plasma samples treated with a high protamine-heparin ratio and those treated with a one-to-one or low protamine-heparin ratio (all p > .05).
Conclusions:
Plasma samples treated with a low protamine-heparin ratio had superior clot growth velocity and larger clot size at 30 min compared to a one-to-one ratio, supporting the notion that a low protamine-heparin ratio may optimize enzymatic coagulation after cardiopulmonary bypass.
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