Disordered hemostasis associated with severely depressed fibrinolysis demonstrated using a simultaneous thrombin and plasmin generation assay during L-asparaginase induction therapy in pediatric acute lymphoblastic leukemia

Thrombin Generation Profile Using ST-Genesia after PEG-asparaginase in Pediatric Patients with Acute Lymphoblastic Leukemia

BACKGROUND

 Venous thromboembolism (VTE) etiology in children with acute lymphoblastic leukemia (ALL) is multifactorial. The use of global assays of hemostasis as a thrombin generation test (TGT) is useful to individualize VTE risk in adult patients. This prospective cohort study aimed to evaluate the usefulness of an automated TGT to evaluate VTE risk during ALL treatment in children.

METHODS

 TGT (automated analyzer ST Genesia; ThromboScreen) and pro- and anticoagulant plasma proteins were analyzed during ALL treatment in pediatric patients following LAL-SEHOP-PETHEMA-2013 guidelines. Results were compared with a series of pediatric normal controls and evaluated according to pegylated asparaginase PEG-ASP administration and to VTE risk factors.

RESULTS

 The study included 67 patients: males n = 35, B-ALL (n = 60). None had a VTE during the evaluated period. Compared to healthy controls, the normalized endogenous thrombin potential (N-ETP) ratio in patients was higher and ETP inhibition (ETP-inh) was lower, especially after PEG-ASP administration. Plasmatic protein C and protein S levels decreased after PEG-ASP administration, but antithrombin mean level did not. A bivariant analysis showed that ETP-inh was lower in patients >10 years old (p = 0.05) and in those with non-O blood type (p = 0.005). A linear mixed model also showed a higher TGT prothrombotic profile in patients with inherited thrombophilia.

CONCLUSION

 TGT could be a biomarker of a high VTE risk in ALL pediatric patients. Non-O blood group and inherited thrombophilia were associated with a significantly higher thrombotic profile, and an increased profile was also observed after administration of PEG-ASP.

Characterization of thrombophilia-related plasmas evaluated by anticoagulants-mediated thrombin and plasmin generation assays

Disturbances in the balance between coagulation, anticoagulation and fibrinolysis may lead to thrombosis or haemorrhage. Simultaneous assessments of thrombin and plasmin facilitate overall understandings of pathological haemostasis, especially for thrombophilia. Here, we characterized coagulation-fibrinolysis potentials in plasmas with thrombophilia using anticoagulants-mediated thrombin-plasmin generation assay (T/P-GA). T/P-GA was initiated by adding tissue factor, tissue-type plasminogen activator and anticoagulants [recombinant-thrombomodulin (rTM), activated protein (P)C (APC) and antithrombin (AT)], followed by simultaneous thrombin generation and plasma generation monitoring. Patients' plasmas with PC-deficiency (PC-def), PS-deficiency (PS-def), AT-deficiency (AT-def), factor VLeiden (FVL) and antiphospholipid syndrome (APS) were evaluated. A ratio of peak-thrombin (or peak-plasmin) with and without anticoagulants was calculated as anticoagulants (+)/anticoagulants (-). First, TG, in rTM-mediated, PC-def, PS-def and FVL showed higher peak-thrombin ratios than the controls, whereas AT-def and APS exhibited no differences from the controls. In APC-mediated, PC-def, PS-def and AT-def showed low peak-thrombin ratios, similar to the controls, but immune-depleted PS-def (<1%) showed the higher ratio than the controls. FVL and APS showed higher peak-thrombin ratios than the controls. In AT-mediated, peak-thrombin ratios in PS-def, PC-def and APS were lower than in controls, but those in AT-def and FVL was not significantly different from the controls. Second, PG, in rTM-mediated, all thrombophilia plasmas showed low peak-plasmin ratios (∼0.5), but no significant difference was observed, relative to the controls. In APC and AT-mediated, peak-plasmin ratios in thrombophilia-related plasmas were similar to the controls (∼1.0). Anticoagulants-mediated T/P-GA may classify thrombin generation characteristics in thrombophilia-related plasmas upon adding anticoagulants.

Altered Fibrinolysis in Hematological Malignances

Bleeding and thrombosis are well-known complications to hematological malignancies, and changes in fibrinolysis impact both these issues. In the present systematic review, we provide an overview and discussion of the current literature in regards to clinical manifestations, diagnosis, and treatment of altered fibrinolysis in patients suffering from hematological malignancies, beyond acute promyelocytic leukemia. We performed a systematic literature search employing the databases Pubmed, Embase, and Web of Science to identify original studies investigating fibrinolysis in hematological malignancies. Studies investigating fibrinolysis in acute promyelocytic leukemia or disseminated intravascular coagulation were excluded. We identified 32 studies fulfilling the inclusion criteria. A majority of the studies were published more than two decades ago, and none of the studies examined all available markers of fibrinolysis or used dynamic clot lysis assays. In acute leukemia L-asparaginase treatment induced a hypofibrinolytic state, and prior to chemotherapy there seemed to be little to no change in fibrinolysis. In studies examining fibrinolysis during chemotherapy results were ambiguous. Two studies examining multiple myeloma indicated hypofibrinolysis prior to chemotherapy, and in another plasma cell disease, amyloid light chain-amyloidosis, clear signs of hyperfibrinolysis were demonstrated. In myeloproliferative neoplasms, the studies reported signs of hypofibrinolysis, in line with the increased risk of thrombosis in this disease. Only one study regarding lymphoma was identified, which indicated no alterations in fibrinolysis. In conclusion, this systematic review demonstrated that only sparse, and mainly old, evidence exists on fibrinolysis in hematological malignancy. However, the published studies showed a tendency toward hypofibrinolysis in myeloproliferative disorders, an increased risk of hyperfibrinolysis, and bleeding in patients with AL-amyloidosis, whereas studies regarding acute leukemias were inconclusive except with regard to L-asparaginase treatment, which induced a hypofibrinolytic state.

A Pathological Clarification of Sepsis-Associated Disseminated Intravascular Coagulation Based on Comprehensive Coagulation and Fibrinolysis Function

BACKGROUND

 The functional dynamics of coagulation and fibrinolysis in patients with disseminated intravascular coagulation (DIC) vary due to the pathology and severity of various underlying diseases. Conventional measurements of hemostasis such as thrombin-antithrombin complex, plasmin-α2-plasmin-inhibitor complex, and fibrinogen-fibrin degradation products may not always reflect critical pathophysiologic mechanisms in DIC. This article aims to clarify the pathology of sepsis-associated DIC using assessment of comprehensive coagulation and fibrinolysis.

METHODS

 Plasma samples were obtained from 57 patients with sepsis-associated DIC at the time of initial diagnosis. Hemostasis parameters were quantified by clot-fibrinolysis waveform analysis (CFWA) and thrombin/plasmin generation assays (T/P-GA). The results were expressed as ratios relative to normal plasma.

RESULTS

 CFWA demonstrated that the maximum coagulation velocity (|min1|) ratio modestly increased to median 1.40 (min - max: 0.10 - 2.60) but the maximum fibrinolytic velocity (|FL-min1|) ratio decreased to 0.61 (0 - 1.19). T/P-GA indicated that the peak thrombin (Th-Peak) ratio moderately decreased to 0.71 (0.22 - 1.20), whereas the peak plasmin (Plm-Peak) ratio substantially decreased to 0.35 (0.02 - 1.43). Statistical comparisons identified a correlation between |min1| and Th-Peak ratios (ρ = 0.55, p < 0.001), together with a strong correlation between |FL-min1| and Plm-Peak ratios (ρ = 0.71, p < 0.001), suggesting that CFWA reflected the balance between thrombin and plasmin generation. With |min1| and |FL-min1| ratios, DIC was classified as follows: coagulation-predominant, coagulation/fibrinolysis-balanced, fibrinolysis-predominant, and consumption-impaired coagulation. The majority of patients in our cohort (80.7%) were coagulation-predominant.

CONCLUSION

 A pathological clarification of sepsis-associated DIC based on the assessment of coagulation and fibrinolysis dynamics may be useful for the hemostatic monitoring and management of optimal treatment in these individuals.