Thromboelastometric detection of clotting Factor XIII deficiency in cardiac surgery patients

Factor XIII levels, clot strength, and impact of fibrinogen concentrate in infants undergoing cardiopulmonary bypass: a mechanistic sub-study of the FIBCON trial

BACKGROUND

Acquired factor XIII (FXIII) deficiency after major surgery can increase postoperative bleeding. We evaluated FXIII contribution to clot strength and the effect of fibrinogen concentrate administration on FXIII activity in infants undergoing cardiac surgery using cardiopulmonary bypass.

METHODS

We conducted a prospectively planned, mechanistic sub-study, nested within the Fibrinogen Concentrate Supplementation in the Management of Bleeding During Paediatric Cardiopulmonary Bypass: A Phase 1B/2A, Open-Label Dose Escalation Study (FIBCON) trial, which investigated fibrinogen concentrate supplementation during cardiopulmonary bypass (ISRCTN: 50553029) in 111 infants (median age 6.4 months). The relationships between platelet number, fibrinogen concentration, and FXIII activity with rotational thromboelastometry clot strength (EXTEM-MCF) in blood taken immediately before cardiopulmonary bypass and after separation from bypass were estimated using multivariable linear regression. Changes in coagulation variables over time were quantified using a generalised linear model comparing three groups: fibrinogen concentrate-supplemented infants, placebo, and a third cohort with lower bleeding risk.

RESULTS

Overall, 48% of the variability (multivariable R²) in EXTEM-MCF clot strength was explained by three factors: the largest contribution was from FXIII activity (partial R²=0.21), followed by platelet number (partial R²=0.14), and fibrinogen concentration (partial R²=0.095). During cardiopulmonary bypass, mean platelet count fell by a similar amount in the three groups (-36% to -41%; interaction P=0.98). Conversely, fibrinogen concentration increased in all three groups: 132% in the fibrinogen concentrate-supplemented group, 26% in the placebo group, and 51% in the low-risk group. A similar increase was observed for FXIII activity (61%, 23%, and 25%, respectively; interaction P<0.0001).

CONCLUSIONS

FXIII contribution to clot strength is considerable in infants undergoing cardiac surgery. Fibrinogen concentrate supplementation also increased FXIII activity, and hence clot strength.

CLINICAL TRIAL REGISTRATION

ISRCTN: 50553029.

The impact of acquired coagulation factor XIII deficiency in traumatic bleeding and wound healing

Factor XIII (FXIII) is a protein involved in blood clot stabilisation which also plays an important role in processes including trauma, wound healing, tissue repair, pregnancy, and even bone metabolism. Following surgery, low FXIII levels have been observed in patients with peri-operative blood loss and FXIII administration in those patients was associated with reduced blood transfusions. Furthermore, in patients with low FXIII levels, FXIII supplementation reduced the incidence of post-operative complications including disturbed wound healing. Increasing awareness of potentially low FXIII levels in specific patient populations could help identify patients with acquired FXIII deficiency; although opinions and protocols vary, a cut-off for FXIII activity of ~ 60–70% may be appropriate to diagnose acquired FXIII deficiency and guide supplementation. This narrative review discusses altered FXIII levels in trauma, surgery and wound healing, diagnostic approaches to detect FXIII deficiency and clinical guidance for the treatment of acquired FXIII deficiency.

Rotational Thromboelastometry for Assessing Bleeding Complications and Factor XIII Deficiency in Cardiac Surgery Patients

We aimed to detect alterations and deficits in hemostasis during cardiac surgery with cardiopulmonary bypass (CPB) using point-of-care-supported coagulation analysis (rotational thromboelastometry, impedance aggregometry), in addition to single factor assays for the measurement of fibrinogen (FI) and factor XIII (FXIII) levels. Forty-one patients scheduled for elective cardiac surgery with CPB were enrolled in this observational study. Perioperative measurement (pre-, postheparin, 30-minutes before the end of bypass, 1-hourpostoperatively) of standard laboratory variables, additional rotational thromboelastometry (ROTEM; International GmbH, Munich, Germany), Multiplate analysis (Roche, Switzerland), and an assay of FXIII activity were performed as well as the collection of epidemiological data and blood loss. The FI and FXIII levels as well as the measured ROTEM and Multiplate parameters correlated weakly with the blood loss. Clotting time and maximum clot firmness (MCF) of the intrinsically activated ROTEM showed a good correlation (r_CT-INTEM = 0.378; P < .05, r_MCF-INTEM = 0.305; P < .05) with postoperative drainage loss, suggesting a dependence of blood loss on the initial intrinsic activity. Additionally, perioperative FI or FIBTEM levels and the FXIII levels correlated with each other. Intrinsically activated ROTEM showed a good correlation with postoperative drainage loss, thus suggesting a dependence of blood loss on the initial intrinsic activity and therefore facilitating clinicians to assess postoperative bleeding complications. Based on the FI level or the MCF_FIBTEM measured by ROTEM, it may also be possible to assess the FXIII concentration. Especially in chronically ill and massive bleeding cardiac surgery patients with significantly decreased FXIII levels, the knowledge of FXIII deficiency may help clinicians to treat coagulation disorders more adequately.

[Modern coagulation management in bleeding trauma patients : Point-of-care guided administration of coagulation factor concentrates and hemostatic agents]

BACKGROUND

Uncontrolled bleeding with trauma-induced coagulopathy (TIC) is still the leading cause of preventable death following severe multiple injury. Rapid diagnosis and treatment are associated with improved outcome. Early individualized goal-directed therapy and the use of point-of-care technology may be superior to empiric and ratio-based therapies with conventional blood products.

MATERIALS AND METHODS

Selective review of the literature considering current recommendations/expert opinion for coagulation management in bleeding trauma patients via individualized goal-directed therapy and the use of viscoelastic point-of-care (ROTEM®)-guided substitution of coagulation factor concentrates and hemostatic agents.

RESULTS

The administration of fibrinogen concentrate in bleeding trauma patients may be considered if ROTEM®-FIBTEM A10 < 10 mm (FIBTEM A5 < 9 mm; FIBTEM MCF < 12 mm) and EXTEM A10 < 45 mm (EXTEM A5 < 35 mm; EXTEM MCF < 55 mm); the administration of prothrombin complex concentrate (PCC) may be considered if signs of delayed coagulation initiation (ROTEM®-EXTEM CT > 80 s). At this stage, no concluding statement can be made for monitoring or treatment guidance with factor XIII by using point-of-care technology. Viscoelastic assays display high sensitivity and specificity for the detection of hyperfibrinolysis with subsequent administration of an antifibrinolytic.

CONCLUSIONS

Individualized therapeutic concepts based upon viscoelastic point-of-care (ROTEM®) assays present an alternative to empiric and ratio-based therapies with conventional blood products in bleeding trauma patients and may be associated with reduced need for allogenic blood products and morbidity.

The Effect of Ex Vivo Factor XIII Supplementation on Clot Formation in Blood Samples From Cardiac and Scoliosis Surgery Patients

Excessive perioperative bleeding remains a substantial problem. Factor XIII (FXIII) contributes to clot stability, and it has therefore been suggested that supplementation with FXIII concentrate may improve perioperative hemostasis. We evaluated the effects of increasing doses of FXIII, alone or in combination with fibrinogen or platelet concentrate, in blood samples from 2 considerably different groups of surgical patients: cardiac and scoliosis surgery patients. Whole-blood samples were collected immediately after operation from cardiac and scoliosis surgery patients. The samples were supplemented with 3 clinically relevant doses of FXIII concentrate (+20%, +40%, and +60%), alone or in combination with a fixed dose of fibrinogen concentrate (+1.0 g/L) or fresh apheresis platelets (+92 × 10⁹/L). Clot formation was assessed with rotational thromboelastometry (ROTEM). When the highest dose of FXIII concentrate was added, EXTEM clotting time was shortened by 10% in both cardiac and scoliosis surgery patients (95% confidence intervals: 2.4%-17% and 3.3%-17%, respectively), and FIBTEM maximum clot firmness was increased by 25% (9.3%-41%) in cardiac patients, relative to baseline. When fibrinogen was added, the dose-dependent effect of FXIII on clot stability was maintained, but the total effect was markedly greater than with FXIII alone, +150% (100%-200%) and +160% (130%-200%) for the highest FXIII dose in cardiac and scoliosis patients, respectively. Ex vivo supplementation with clinically relevant doses of FXIII improved clot formation moderately in blood samples from cardiac and scoliosis surgery patients, both alone and when given in combination with fibrinogen or platelet concentrate.

Rotational thromboelastometry can detect factor XIII deficiency and bleeding diathesis in patients with cirrhosis

BACKGROUND & AIMS

Patients with progressive liver disease exhibit complex coagulation disorders. Factor XIII plays a crucial role in the last steps of haemostasis, and its deficiency is associated with an increased incidence of bleeding diathesis. However, current conventional coagulation tests cannot detect factor XIII deficiency. In this study, we examined factor XIII activity and the ability of rotational thromboelastometry to detect factor XIII deficiency and bleeding diathesis in patients with cirrhosis.

METHODS

We retrospectively studied 74 patients with cirrhosis, comparing the results of conventional coagulation tests (international normalized ratio, activated partial thromboplastin time, platelet count, fibrinogen level), rotational thromboelastometry, factor XIII activity and clinical scores.

RESULTS

Patients with cirrhosis exhibited reduced factor XIII activity. Factor XIII activity was positively correlated with conventional coagulation parameters and rotational thromboelastometry values, such as maximum clot formation (MCF)_extem (r=.48, P<.0001) and MCF_fibtem (r=.60, P<.0001). However, maximum lysis (ML)_extem and ML_aptem were not correlated with factor XIII activity. Three-month mortality rates (P=.0469) and bleeding complications (P<.0001) were significantly associated with lower factor XIII activity. Patients with haemorrhage exhibited significantly altered rotational thromboelastometry values.

CONCLUSIONS

Reduced levels of MCF_extem and MCF_fibtem but not high levels of ML_extem and ML_aptem are associated with factor XIII deficiency in patients with liver disease. Therefore, substituting factor XIII should be considered for such patients to strengthen clot formation in patients experiencing haemorrhage or those who have undergone interventions.

Use and Future Investigations of Recombinant and Plasma-Derived Coagulation and Anticoagulant Products in the Neonate

Although congenital bleeding disorders can manifest in the newborn period, the most common causes of bleeding and thrombosis in neonates are acquired conditions. Factor concentrates are used for specific diagnoses (hemophilia with inhibitors, specific factor deficiency, von Willebrand disease) and approved indications, and increasingly for off-label indications (bleeding in surgery cardiopulmonary bypass, extracorporeal membrane oxygenation). We will review the approved indications for factor products in the neonate and discuss the evidence and rationale for off-label use of factor products in management of bleeding and thrombosis in the neonate.