Noninvasive method for measuring thrombus formation in patients after peripheral angioplasty using three-dimensional...

Clinical investigations studying the effect of newer medications on such complex pathophysiology as the formation of an arterial or venous mural thrombus have been limited to clinical symptomatic endpoints. Biochemical markers so far have not been convincing in quantifying ongoing thrombus formation. Consequently, clinical development of new antithrombotic compounds has had to rely on clinical symptoms that occur either comparably late in the course of the disease and may therefore be influenced by many other factors, or on those symptoms that occur at a relatively low incidence rate. Both circumstances make studies for dose-finding and determination of optimal drug regimens more difficult and time consuming. Using conventional clinical noninvasive ultrasonography, the volume and geometry of a peripheral arterial segment can be measured with high sensitivity and reproducibility in healthy volunteers (% coefficient of variation = 8.01%). In patients, thrombus volume was monitored after peripheral transluminal angioplasty of the femoral artery. All patients received a standard anticoagulant treatment with heparin for 24 hours after the procedure. Volume measurements were performed at 20, 29, 44, 53, and 68 hours after angioplasty. When compared with the obstruction volume at 20 hours, a slight increase could be detected at 29, 44, and 53 hours. At 68 hours there was a significant increase in obstruction volume. This indicates that volume measurements may detect changes in the course of thrombus formation, related to the antithrombotic treatment regimen, at a level at which clinical symptoms may not be present.