For patients with mild bleeding symptoms, increased propensity for bleeding has been thought to be related to intensified fibrinolysis. However, in a study published in Thrombosis Research, a research team has reported that this may not be the case.
In this observational study of preoperative patients, a cohort of 240 patients had self-reported bleeding symptoms while the other cohort of 95 patients did not. Blood counts and clot-related factors were measured.
While clot lysis relates to bleeding, it has been difficult to measure this phenomenon in patients. The researchers employed highly sensitive techniques to measure fibrinolysis in blood samples. These included a plasma turbidity lysis assay and the tissue Plasminogen Activator-Rotational Thromboelastometry (tPA-ROTEM) applied to whole blood. Multivariate regression analyses were used to evaluate results.
According to tPA-ROTEM measurements, patients with self-reported bleeding symptoms showed significantly longer lysis times (P =.022) compared with patients without bleeding symptoms. The patients in the cohort with bleeding symptoms also showed significantly slower lysis speeds (P =.007).
However, these results were not consistent with those obtained from turbidity lysis measurements. In turbidity lysis assays, patients with self-reported bleeding symptoms showed lysis times (P =.065) and lysis speeds (P =.26) similar to those of the other cohort.
Results from each technique can be affected by various clotting factors, but overall the study showed no evidence of greater fibrinolytic activity among patients with self-reported bleeding symptoms. The study authors reported that tPA-ROTEM results were significantly affected by plasminogen activator inhibitor 1 (PAI-1), alpha-2-antiplasmin, factor XII, factor II, thrombin activatable fibrinolysis inhibitor (TAFI), and plasminogen. In turbidity lysis assays, TAFI, PAI-1, fibrinogen, and alpha-2-antiplasmin were influential.
According to the authors, results from the 2 techniques used in this study suggested an ability to identify imbalances in fibrinolytic factors. The authors recommended that this possibility should be further examined in patients with known conditions related to fibrinolysis.
1. Vries MJA, Macrae F, Nelemans PJ, et al. Assessment and determinants of whole blood and plasma fibrinolysis in patients with mild bleeding symptoms [published online December 4, 2018]. Thromb Res. doi: 10.1016/j.thromres.2018.12.004