Relationship between thrombin generation parameters and prothrombin fragment 1 + 2 plasma levels

Temporal changes in markers of coagulation and fibrinolysis in adults during extracorporeal membrane oxygenation

INTRODUCTION

Bleeding and thrombotic events (BTE) are frequent during extracorporeal membrane oxygenation (ECMO). They occur at varying timepoints and may be affected by temporal changes in coagulation and fibrinolysis. We aimed to assess various coagulation and fibrinolytic markers over time and their relationship with BTE.

METHODS

A single-centre prospective study was performed in 17 patients with severe respiratory failure receiving veno-venous ECMO. Blood samples were collected before and during ECMO, and around circuit decannulation.

RESULTS

Prior to ECMO, D-Dimer, Plasmin-Antiplasmin complexes (PAP), Plasminogen-Activator Inhibitor-1 (PAI-1) and fibrinogen were elevated. There was an increase in D-Dimer and Prothrombin Fragments 1+2 (PF1+2) (729 to 1305pmol/L, p = .034) by day 1 and PAP increased by day 2 from baseline levels (median 1022 to 1797 µg/L, p = .023). There was a strong positive correlation in PAP, PF1+2 and thrombin-antithrombin complexes (TAT) to D-Dimer. BTE were frequent - 18% had major extracranial haemorrhage and 24% had intracranial haemorrhage. Over time, there was a progressive elevation PAP in patients developing subsequent extracranial haemorrhage, whereas D-Dimer, PAP and PF1+2 increased after intracranial haemorrhage.

CONCLUSIONS

There were early changes in coagulation activity during ECMO by PF1+2 followed by subsequent fibrinolysis by PAP. Changes in PAP, PF1+2 and TAT were associated with major haemorrhage.

Myocardial injury after non-cardiac surgery and per operative fibrin metabolism in patients undergoing hip-fracture surgery: an observational study

Myocardial injury after non-cardiac surgery (MINS) is associated with a 2-3-fold increased risk of subsequent major cardiovascular events and postoperative mortality. The pathological mechanism behind MINS is not fully uncovered. We hypothesized that patients with MINS following hip fracture surgery would have an altered haemostatic balance pre- and postoperative compared with patients without MINS. This was investigated in a prospective single-centre observational study including patients consecutively. The outcomes were changes in thrombin generation, fibrinogen/fibrin turnover, tissue plasminogen activator, plasminogen activator inhibitor-1 and fibrin structure measurements in patients developing MINS and patients who did not. Outcomes were measured preoperatively and two hours postoperatively. Seventy-two patients were included whereof 26 (36%) patients developed MINS. D-dimer delta values were significantly higher in patients developing MINS than in patients who did not (p = 0.01). After adjusting for age, sex, smoking, alcohol abuse, atrial fibrillation, anticoagulant medication preoperative CRP, preoperative creatinine and duration of surgery, the association remained significant (p = 0.04). There were no significant changes in thrombin generation, in markers of fibrinogen/fibrin turnover besides D-dimer, or in fibrin structure measurements pre- and postoperatively between patients with and without MINS. As such, a relationship between the coagulative and fibrinolytic activity and MINS cannot be ruled out in patients with MINS after hip fracture surgery. Registration: The study was an observational sub-study to a multicentre randomised clinical trial registered at ClinicalTrials.gov (NCT02344797).

Enhanced in vivo and ex vivo thrombin generation after lower-leg trauma, but not after knee arthroscopy

BACKGROUND

There is room for improvement of prevention of venous thromboembolism (VTE) after lower-leg cast application or knee arthroscopy. Information about the mechanism of clot formation in these patients may be useful to identify new prophylaxis targets. We aimed to study the effect of 1) lower-leg injury and 2) knee arthroscopy on thrombin generation.

METHODS

A cross-sectional study was conducted using plasma samples of POT-(K)CAST trials to measure ex vivo thrombin generation (Calibrated Automated Thrombography [CAT]) and plasma levels of prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin (TAT), fibrinopeptide A (FPA). Plasma was obtained shortly after lower-leg trauma or before and after (< 4 h) knee arthroscopy. Participants were randomly selected from those who did not develop VTE. For aim 1, samples of 88 patients with lower-leg injury were compared with 89 control samples (i.e., preoperative samples of arthroscopy patients). Linear regression was used to obtain mean differences (or ratios if ln-retransformed because of skewedness) adjusted for age, sex, body mass index, comorbidities. For aim 2, pre- and postoperative samples of 85 arthroscopy patients were compared, for which mean changes were obtained.

RESULTS

In patients with lower-leg injury (aim 1), endogenous thrombin potential, thrombin peak, velocity index, FPA and TAT were increased as compared with controls. In arthroscopy patients (aim 2), pre- and postoperative levels were similar for all parameters.

CONCLUSION

Lower-leg trauma increases thrombin generation both ex vivo and in vivo, in contrast to knee arthroscopy. This may imply that the pathogenesis of VTE is different in both situations.