Influence of factor IX on overall plasma coagulability and fibrinolytic potential as measured by global assay: monitoring in haemophilia B

Abstract

We sought to determine the influence of factor IX (FIX) deficiency upon overall coagulative and fibrinolytic capacities in plasma using the clot formation and lysis (CloFAL) assay, and to investigate the role of this global assay as an adjunctive monitoring tool in haemophilia B. CloFAL assay parameters were measured in vitro in platelet-poor plasma in relation to FIX activity and antigen (FIX:Ag), and were determined ex vivo among FIX-deficient patients (n = 41) in comparison to healthy individuals (n = 48). Supplementation of FIX-deficient plasma with FIX in vitro demonstrated a non-linear concentration dependence of FIX upon overall plasma coagulability. Ex vivo, coagulability was significantly decreased in FIX-deficient vs. healthy subjects among adults [median coagulation index (CI): 4% vs. 104% respectively; P < 0.001] and children (median CI: 9% vs. 63%; P < 0.001). Fibrinolytic capacity was increased in adult FIX-deficient vs. healthy subjects (median fibrinolytic index: 216% vs. 125%, respectively, P < 0.001), and was supported by a trend in shortened euglobulin lysis time (ELT). Severe haemophilia B patients showed heterogeneity in aberrant CloFAL assay waveforms, influenced partly by FIX:Ag levels. Patients with relatively preserved FIX:Ag (i.e. dysfunctional FIX) exhibited a shorter time to maximal amplitude in clot formation than those with type I deficiency. During patient treatment monitoring, markedly hypocoagulable CloFAL assay waveforms normalized following 100% correction with infused FIX. The CloFAL global assay detects FIX deficiency, demonstrates differences in coagulability between dysfunctional FIX and type I deficiency, and appears useful as an adjunctive test to routine FIX measurement in monitoring haemophilia B treatment.

Elevated lipoprotein (a), small apolipoprotein (a), and the risk of arterial ischemic stroke in North American children

“…The CloFAL assay monitored kinetic light absorbance measurements in plasma following the addition of a reagent comprising trace lipidated tissue factor for coagulation activation and tissue plasminogen activator for acceleration of clot lysis, resulting in a clot formation and lysis waveform, as previously described. [22][23][24] A recently-updated fibrinolytic index (FI 2 ) was employed. 25 ECLA was performed by an automated spectrophotometric technique as previously described, and the results are expressed as the euglobulin lysis time (ELT).…”

Accumulation of functional recombinant human coagulation factor IX in transgenic soybean seeds

“…When compared to normal human clotting activity (that of adults with a FIX concentration of 5 lg ml -1 of blood), which normally reach 100% when measured with the aPTT method (Hoffer et al 1999;Acar et al 2006), the coagulation rates of 1.0-1.4% observed in the soybean TSP extracts were low. However, in most cases, haemophilia B patients usually require FIX supplementations with 10% of clotting activity to provide proper coagulation rates, and a significant haemostatic effect can be achieved with the elevation of the FIX levels in the blood to only 0.8 IU dl -1 (Kay et al 2000;Goldenberg et al 2008). In addition, experiments have been carried out to obtain purified hFIX from soybean seeds.…”

Coagulative function assessed preoperatively via the clot formation and lysis assay as a prognostic factor for blood loss in adolescents undergoing posterior spinal fusion for idiopathic scoliosis

“…This evaluation revealed an independent association of increased plasma coagulative capacity with decreased intraoperative blood loss, as well as a significantly lower baseline plasma coagulative capacity among patients in the highest quartile of EBL as compared to the lowest quartile, which was not detected by routine clinical coagulation testing (PT, aPTT, platelet count). It must be pointed out that the CloFAL assay has been shown in prior work to be sensitive to multiple physiological and pathologic alterations in fibrinolysis and in secondary hemostasis (including factors and inhibitors of the intrinsic, extrinsic, and common pathways of the coagulation), but is not designed to assess primary hemostasis (ie, platelet function and platelet‐endothelial interactions). We cannot exclude the possibility that platelet function and/or collagen function contributes in part to the marked intraoperative blood loss observed in some adolescents with IS undergoing PSF.…”

“…20 The CloFAL assay has broad sensitivity to multiple coagulation factor deficiencies and functional defects, as well as multiple abnormalities in the fibrinolytic system. [20][21][22][23][24] It is of interest to investigate the utility of the CloFAL assay, in the context of routine clinical coagulation tests and clinical factors, to preoperatively identify adolescent IS patients at increased bleeding risk, and in the future to risk-stratify these patients prior to surgery.…”

“…Unlike routine clinical coagulation tests (prothrombin time (PT) and activated partial thromboplastin time [aPTT]), but like TEG and ROTEM, the clot formation and lysis (CloFAL) assay measures both the kinetics and magnitude of ex vivo clot formation and fibrinolysis in plasma . The CloFAL assay has broad sensitivity to multiple coagulation factor deficiencies and functional defects, as well as multiple abnormalities in the fibrinolytic system . It is of interest to investigate the utility of the CloFAL assay, in the context of routine clinical coagulation tests and clinical factors, to preoperatively identify adolescent IS patients at increased bleeding risk, and in the future to risk‐stratify these patients prior to surgery.…”