Prediction of recurrent venous thromboembolism by clot lysis time: a prospective cohort study

PLoS One. 2012;7(12):e51447. doi: 10.1371/journal.pone.0051447. Epub 2012 Dec 11.

Abstract

Venous thromboembolism (VTE) is a chronic disease, which tends to recur. Whether an abnormal fibrinolytic system is associated with an increased risk of VTE is unclear. We assessed the relationship between fibrinolytic capacity (reflected by clot lysis time [CLT]) and risk of recurrent VTE. We followed 704 patients (378 women; mean age 48 yrs) with a first unprovoked VTE for an average of 46 months after anticoagulation withdrawal. Patients with natural coagulation inhibitor deficiency, lupus anticoagulant, cancer, homozygosity for factor V Leiden or prothrombin mutation, or requirement for indefinite anticoagulation were excluded. Study endpoint was symptomatic recurrent VTE. For measurement of CLT, a tissue factor-induced clot was lysed by adding tissue-type plasminogen activator. Time between clot formation and lysis was determined by measuring the turbidity. 135 (19%) patients had recurrent VTE. For each increase in CLT of 10 minutes, the crude relative risk (RR) of recurrence was 1.13 (95% CI 1.02-1.25; p = 0.02) and was 1.08 (95% CI 0.98-1.20; p = 0.13) after adjustment for age and sex. For women only, the adjusted RR was 1.14 (95% CI, 0.91-1.42, p = 0.22) for each increase in CLT of 10 minutes. CLT values in the 4(th) quartile of the female patient population, as compared to values in the 1(st) quartile, conferred a risk of recurrence of 3.28 (95% CI, 1.07-10.05; p = 0.04). No association between CLT and recurrence risk was found in men. Hypofibrinolysis as assessed by CLT confers a moderate increase in the risk of recurrent VTE. A weak association between CLT and risk of recurrence was found in women only.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Blood Coagulation / genetics
  • Cohort Studies
  • Female
  • Fibrin Clot Lysis Time*
  • Humans
  • Male
  • Middle Aged
  • Recurrence*
  • Risk Factors
  • Thrombophilia* / genetics
  • Thrombophilia* / physiopathology
  • Venous Thromboembolism* / blood
  • Venous Thromboembolism* / genetics
  • Venous Thromboembolism* / physiopathology

Grants and funding

This work was supported by grants of the Österreichische Nationalbank and the Medizinisch-Wissenschaftlicher Fonds des Bürgermeisters der Bundeshauptstadt Wien. Both institutions are non-commercial and do not have a potential competing interest. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.