Percutaneous transluminal angioplasty is a minimally invasive procedure for repeated establishment of blood flow through occluded or stenosed arteries. It is a safe and technically very successful method. The main limitation is the re-narrowing of the lumen (restenosis), which occurs in 40 to 60 % of patients within six to 12 months. With a good knowledge of restenosis risk indicators, we can predict prevalence of restenosis. When angioplasty is performed, the vascular wall, which plays a very important role in haemostasis, is often damaged. This suggests that haemostasis plays an important role in the development of restenosis after angioplasty. Therefore, the aim of this thesis was to investigate the relationship between haemostasis and restenosis using two global haemostasis tests (overall haemostatic potential and thrombin generation assay).
We tested the following hypothesis: patients who develop restenosis within 12 months after angioplasty have had significantly altered overall coagulation potential and hypercoagulable thrombogram before and after the procedure.
Patients plasma was analysed before and after percutaneous transluminal angioplasty. Alterations in haemostasis were detected by measuring overall haemostatic potential, thrombin generation, D-dimer and fibrinogen levels. Haemostasis tests results were compared with the prevalence of restenosis after angioplasty. Hypothesis testing of the difference between the two samples showed that thrombin generation significantly differentiated between subjects who developed restenosis and those who did not. Subjects who developed restenosis had a longer lag time and time to peak. There was no significant difference in overall haemostatic potential. Using regression, we demonstrated an independent association with restenosis for all angioplasty variables. Prolonged lag time and time to peak and increased endogenous thrombin potential and peak height are associated with a higher risk of restenosis. Overall haemostatic potential was not independently associated with restenosis in any of the variables. We found that thrombin generation assay has a fairly good predictive value for restenosis, while the overall haemostatic potential method did not prove to be a good indicator.