Changes in the clotting viscoelasticity caused by cardiopulmonary bypass (CPB) surgery

One to three percent of the Open Heart Surgery procedures have abnormal bleeding due to acquired platelet dysfunction. Standard clotting tests to determine the cause of bleeding usually take between 25 and 60 minutes to get results. This time frame is not useful for deciding what type of treatment to give to a patient. More importantly, the standard clotting tests is they cannot determine platelet function. The Thrombo-Visco Elastogram (TVE) is a new test that provides results in less than 15 minutes and has the potential to evaluate platelet function. In this study, we used the TVE test to assess viscoelasticity of clotting blood from patients before and after CPB. For each patient and condition, we tested the blood alone and after incubation with a saturation concentration of ReoProTM, a glycoprotein Ilb/Illa inhibitor. The major findings of this study are: 1) The TVE device is capable of determining with accuracy quantitative changes in blood viscoelasticity during clotting; 2) The TVE-derived coagulation parameters maximum elastic modulus (Emax), maximum rate of change of elastic modulus (E'max), maximum viscosity ([eta]max), and maximum rate of change of viscosity ([eta]'max) and the coagulation parameters prothrombin time (PT), platelet count, fibrinogen concentration and hematocrit are all affected by CPB; 3) The TVE-derived parameters were all substantially affected by incubation of the blood with the platelet GP inhibitor suggesting that these parameters are exquisitely sensitive to platelet function; and 4) In ReoProTM-free blood samples, values of E'max for all patients, before and after CPB, could be predicted as a function of platelet count, fibrinogen concentration and hematocrit. We concluded that the TVE/ReoProTM assay has the potential to assess the contribution of platelet function and soluble components to coagulation in a quantitative, reproducible and practical manner.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

1998

Author dc:creator

• Whitbourne, Peta Gaye

Advisor dc:contributor.advisor

• Jose G. Venegas.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/50547

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/50547