Thromboelastometry as a diagnostic tool in mild bleeding disorders: A prospective cohort study

Thromboelastometry (ROTEM) Assessing Hypercoagulability in Patients Referred for Thrombophilia Screening

INTRODUCTION

Thrombophilia, a blood coagulation disorder, poses risks of venous thromboembolism (VTE). Coagulation assays may not be sufficient to assess VTE risk and global assays such as Rotational Thromboelastometry (ROTEM) may add valuable information. We investigated ROTEM's capacity to detect hypercoagulability in patients undergoing thrombophilia screening, its potential impact on patient outcomes, and limitations.

METHODS

Comprehensive clinical, laboratory, genetic tests, and ROTEM (EXTEM and INTEM) were conducted for 356 patients referred for thrombophilia screening at an academic hospital outpatient unit. Hypercoagulability was identified as a shorter clot formation time (CFT), larger alpha angle (AA), and greater maximum clot firmness (MCF), and was compared in patients with and without VTE. Statistically this was analyzed using Mann-Whitney U and Chi-square tests with p < 0.05 considered significant.

RESULTS

Among 356 patients, 64.6% had previous VTE, with 76.9% experiencing one event, 14.3% recurrent (35.6% unprovoked, 64.4% provoked). 22.5% of patients were on anticoagulation. Those with VTE history exhibited significant alterations in EXTEM and INTEM parameters compared to those without (p < 0.001), showing decreased CFT and increased AA and MCF. However, receiver operating characteristic curves for these variables indicated that none were able to discriminate between those individuals with and without thromboembolic complications.

CONCLUSION

ROTEM does not appear to be a strong discriminatory test. However, it can detect hypercoagulopathy in patients referred for thrombophilia screening. Abnormal ROTEM may indicate a higher risk for recurrence. However, this can only be determined in prospective cohort studies.

Utility of Global Hemostatic Assays in Patients with Bleeding Disorders of Unknown Cause

Bleeding disorder of unknown cause (BDUC) is a diagnosis of exclusion after exhaustive evaluation of plasmatic coagulation and platelet function. This review explores the utility of global hemostatic assays as confirmatory tests and in elucidating the pathophysiology of BDUC. Unlike traditional hemostatic tests that focus on coagulation factors, global assays are conducted both in plasma and also whole blood. These assays provide a more comprehensive understanding of the cell-based model of coagulation, aid in the identification of plasmatic factor abnormalities that may reduce hemostatic capacity, and allow for the assessment of impaired platelet-endothelial interactions under shear stress, as well as hyperfibrinolytic states. While clinical tests such as skin bleeding time and global assays such as PFA-100 exhibit limited diagnostic capacity, the role of viscoelastic testing in identifying hemostatic dysfunction in patients with BDUC remains unclear. Thrombin generation assays have shown variable results in BDUC patients; some studies demonstrate differences compared with healthy controls or reference values, whereas others question its clinical utility. Fibrinolysis assessment in vitro remains challenging, with studies employing euglobulin clot lysis time, plasma clot lysis time, and fluorogenic plasmin generation yielding inconclusive or conflicting results. Notably, recent studies suggest that microfluidic analysis unveils shear-dependent platelet function defects in BDUC patients, undetected by conventional platelet function assays. Overall, global assays might be helpful for exploring underlying hemostatic impairments, when conventional hemostatic laboratory tests yield no results. However, due to limited data and/or discrepant results, further research is needed to evaluate the utility of global assays as screening tools.

Point-of-Care Testing in Patients with Hereditary Disorders of Primary Hemostasis: A Narrative Review

Inherited disorders of primary hemostasis, such as von Willebrand disease and congenital platelet disorders, can cause extensive, typically mucocutaneous bleeding. Assays to diagnose and monitor these disorders, such as von Willebrand factor activity assays and light transmission aggregometry, are performed in specialized hemostasis laboratories but are commonly not available in local hospitals. Due to the complexity and relative scarcity of these conventional assays, point-of-care tests (POCT) might be an attractive alternative in patients with hereditary bleeding disorders. POCTs, such as thromboelastography, are increasingly used to assess hemostasis in patients with acquired hemostatic defects, aiding clinical decision-making in critical situations, such as during surgery or childbirth. In comparison, the use of these assays in patients with hereditary hemostasis defects remains relatively unexplored. This review aims to give an overview of point-of-care hemostasis tests in patients with hereditary disorders of primary hemostasis. A summary of the literature reporting on the performance of currently available and experimental POCTs in these disorders is given, and the potential utility of the assays in various use scenarios is discussed. Altogether, the studies included in this review reveal that several POCTs are capable of identifying and monitoring severe defects in the primary hemostasis, while a POCT that can reliably detect milder defects of primary hemostasis is currently lacking. A better understanding of the strengths and limitations of POCTs in assessing hereditary defects of primary hemostasis is needed, after which these tests may become available for clinical practice, potentially targeting a large group of patients with milder defects of primary hemostasis.

Standardization of definition and management for bleeding disorder of unknown cause: communication from the SSC of the ISTH

In many patients referred with significant bleeding phenotype, laboratory testing fails to define any hemostatic abnormalities. Clinical practice with respect to diagnosis and management of this patient cohort poses significant clinical challenges. We recommend that bleeding history in these patients should be objectively assessed using the International Society on Thrombosis and Haemostasis (ISTH) bleeding assessment tool. Patients with increased bleeding assessment tool scores should progress to hemostasis laboratory testing. To diagnose bleeding disorder of unknown cause (BDUC), normal complete blood count, prothrombin time, activated partial thromboplastin time, thrombin time, von Willebrand factor antigen, von Willebrand factor function, coagulation factors VIII, IX, and XI, and platelet light transmission aggregometry should be the minimum laboratory assessment. In some laboratories, additional specialized hemostasis testing may be performed to identify other rare causes of bleeding. We recommend that patients with a significant bleeding phenotype but normal laboratory investigations should be registered with a diagnosis of BDUC in preference to other terminology. Global hemostatic tests and markers of fibrinolysis demonstrate variable abnormalities, and their clinical significance remains uncertain. Targeted genomic sequencing examining candidate hemostatic genes has a low diagnostic yield. Underlying BDUC should be considered in patients with heavy menstrual bleeding since delays in diagnosis often extend to many years and negatively impact quality of life. Treatment options for BDUC patients include tranexamic acid, desmopressin, and platelet transfusions.

Bleeding disorder of unknown cause: Results from Iranian study

BACKGROUND

Definite diagnosis of patients with mild to moderate bleeding is challenging. Some studies reported that even more than 50% of their patients remained undiagnosed which is classified as a Bleeding disorder of unknown cause (BDUC). This study aims to document the clinical characteristics and proportion of patients with BDUC in the Iranian Comprehensive Hemophilia Care Center (ICHCC) one of the referral centers for diagnosis of congenital bleeding disorder in Iran.

METHODS

This study was conducted on 397 patients who were referred with a bleeding manifestation to ICHCC from 2019 to 2022. Demographic and laboratory data were documented for all patients. Bleeding questionnaires including ISTH-Bleeding Assessment tool (ISTH-BAT) and the Molecular and Clinical Markers for the Diagnosis and Management of Type 1 (MCMDM-1 (ISTH-BAT, MCMDM-1, and the Pictorial Bleeding Assessment Chart (PBLAC) were filled out for all patients. The data were analyzed by the statistical package for social science (SPSS version 22, SPSS, Chicago, Illinois, USA).

RESULTS

BDUC was diagnosed in 200 patients and 197 patients reached the final diagnosis. Hemophilia, von Willebrand disease (VWD), factor (F) VII deficiency, and platelet functional disorders (PFDs) were confirmed in 54, 49, 34, and 15 of the patients, respectively. No significant difference was found in bleeding scores between patients with BDUC and those with confirmed disease. In contrast, after setting cut-off (ISTH-BAT for males ≥ 4 and females ≥ 6 and MCMDM-1 for males ≥ 3 and females ≥ 5) clinically significant difference was found. There was no association between having a positive consanguineous marriage and setting a diagnosis; however, significant associations were seen for having a positive family history of bleeding. Age (OR =0.977, 95% CI.965-0.989), gender (BDUC female, 151/200; final diagnosis female, 95/197) (OR=3.3, 95% CI 2.16-5.06), family history (OR = 3.19, 95% CI 1.99-5.11), and consanguineous marriage (OR=1.59, 95% CI 1.03-2.45) were considered as a risk factor for categorizing the patients with BDUC or final diagnosis.

CONCLUSION

The findings are mainly in line with previous studies about BDUC patients. The large number of patients with BDUC underlines the incompleteness of available routine laboratory tests and shows the necessity of progress in the development of reliable diagnostic tools to identify underlying bleeding disorders.

How I treat. Bleeding Disorder of Unknown Cause (BDUC)

Recent studies have demonstrated that only 30% of patients referred for assessment of a possible bleeding tendency will eventually be diagnosed with a mild bleeding disorder (MBD) such as von Willebrand disease (VWD) or platelet function defect (PFD). Rather, the majority of such patients will be diagnosed with Bleeding Disorder of Unknown Cause (BDUC). There remains an important unmet need to define consensus regarding the clinical and laboratory criteria necessary for a formal BDUC diagnosis. Nevertheless, BDUC already accounts for more than 10% of patients registered in some Haemophilia Comprehensive Care centres. Accumulating recent data suggest that BDUC is also being diagnosed with increasing frequency. Increased BAT scores are widely utilized to differentiate significant from trivial symptoms in patients with mucocutaneous bleeding. Objective assessment of bleeding phenotype using a standardised bleeding assessment tool (BAT) therefore represents a fundamental first step in the diagnosis of BDUC. Since BDUC is a diagnosis by exclusion, accurate quantification of bleeding phenotype is critical as this will be the primary determinant upon which a diagnosis of BDUC is reached. Importantly, BAT scores suggest that patients with BDUC display bleeding phenotypes comparable to those seen in patients with VWD or PFD respectively. Despite the prevalence of BDUC, diagnosis and management of these patients commonly pose significant clinical dilemmas. In this manuscript, we consider these challenges in the context of a number of typical case studies, discuss the available evidence and outline our approach to the management of these patients.