Thromboelastography (TEG®) compared with total platelet count in thrombocytopenia haematological malignancy patients with bleeding: a pilot observational study

Impact of Factor Xa Inhibition on Coagulation, Platelet Reactivity, and Thrombosis in Patients with Peripheral Artery Disease

BACKGROUND

The role of thrombin in vascular pathology is a focus of investigation. The incorporation of direct Factor Xa inhibition into practice patterns is based on its theoretical dual-pathway attenuation of both thrombin generation and platelet aggregation. However, quantification of the effect of direct anti-Xa medications on platelet function is not established. Thromboelastography with platelet mapping (TEG-PM) leverages dual-pathway metrics to provide comprehensive coagulation profiles. We evaluated the effects of direct oral anticoagulants (DOACs) on coagulation and platelet function profiles and correlate these data with postoperative major adverse limb events (MALEs) in patients with PAD.

METHODS

We conducted a prospective study of patients undergoing lower extremity revascularization with serial perioperative TEG-PM analysis. Patients on DOACs were compared to those not on DOACs, and stratified by concurrent mono-antiplatelet or dual-antiplatelet regimens (MAPT/DAPT). Postoperative MALE was recorded and difference in antithrombotic regimens and TEG-PM analysis compared between groups.

RESULTS

Four hundred seventy-one samples from 141 patients were analyzed. Twenty-nine point five percent were reflective of circulating DOAC therapy. Compared to MAPT alone, patients on DOAC + MAPT exhibited longer time to clot formation (R-time) [7.4 (±2.4) vs. 6.7 (±2.7); P < 0.02], but less platelet inhibition. Patients on DAPT exhibited greater platelet inhibition compared to either group [23.7 (±26.9) vs. 31.0 (±28.3) vs. 42.2 (±31.2); P < 0.01]. Patients who experienced MALE were more likely to be on DOAC therapy [43.8% vs. 22.0% P = 0.02]. Thromboelastography with platelet mapping analysis from patients who experienced MALE also demonstrated longer R-time [8.6 (±3.9 vs. 7.3 (±3.0); P = 0.05] and increased maximum clot amplitude (MA) [66.7 (±4.2) vs. 61.8 (±8.2); P = 0.001].

CONCLUSIONS

Direct oral anticoagulant therapy resulted in a prolonged R-time but had no impact on platelet inhibition. Patients who experienced MALE were more often on DOACs and demonstrated an increased R-time, but also showed greater platelet reactivity evident by increased MA, suggesting DOACs may not be effective at protecting against MALE. Further research comparing DOAC therapy to a DAPT approach may add clarity to emerging multimodal antithrombotic recommendations.

CREST: clinical bleeding and risk evaluation in hematology-oncology patients: a systematic review and meta-analysis of thromboelastography's role

Thrombocytopenia and bleeding are common complications of hematologic malignancies. Often, prophylactic platelets are administered to minimize bleeding risk, based on total platelet count (TPC). However, TPC is a poor predictor, and does not provide rapid information. This review presents a novel prospective in the use of point-of-care viscoelastic studies to assess bleeding risk and guide transfusion therapy in a haematological oncological population, where its use can be extended to a ward level as a bedside test. Monitoring TEG maximum amplitude trends may be useful to guide transfusion protocols, especially for patients with total platelet counts ranging 30-100 × 10 9 /l. Fibrinogen assessment in this group of patients may identify other blood components that require replacing to reduce bleeding risk. Normal maximum amplitude parameters for patients with low platelet counts can be a reassuring sign. This meta-analysis serves to remind the reader that absolute platelet quantity does not equate to the quality of clot formation.

Acute coronary syndrome in patients with cancer

INTRODUCTION

Improvement in cancer survival has led to an increased focus on cardiovascular disease as the other major determinant of survivorship. As a result, there has been an increasing interest in managing cardiovascular disease during and post cancer treatment.

AREAS COVERED

This article reviews the current literature on the pathogenesis, risk factors, presentation, treatment and clinical outcomes of acute coronary syndrome (ACS) in patients with cancer.

EXPERT OPINION

There is growing evidence that both medical therapy and invasive management of ACS improve outcomes in patients with cancer. Appropriate patient selection, risk stratification and tailored therapy represents the cornerstone of management in these patients.

Cryoprecipitate as an alternative to platelet transfusion in thrombocytopenia

Platelet transfusions are not always available for bleeding in severe thrombocytopenia, as storage outside of major centers is limited by their short shelf-life. Data are lacking to support alternative available blood products; however, additional fibrinogen has been shown to enhance clot formation in vitro. To test the hypothesis that cryoprecipitate supplementation could improve clot formation in severe thrombocytopenia, eight hematological malignancy patients with platelet counts under 10 × 109/L each had 10 units of apheresis cryoprecipitate transfused prior to planned prophylactic platelet transfusions. The primary endpoint of thromboelastometry amplitude at 20 min increased by a mean of 5.1 mm (p < 0.01) following cryoprecipitate transfusion despite persisting thrombocytopenia. Thromboelastometry clotting times reduced by a mean of 7.8 s (p < 0.05) and alpha angle increased by a mean of 10.6⁰ (p < 0.01). These results are consistent with cryoprecipitate enhancing the strength of the fibrin/platelet meshwork within the forming thrombus. While platelet transfusion remains the standard of care, where platelet supplies are limited, these data provide a rationale for the use of cryoprecipitate to obtain hemostasis in bleeding thrombocytopenic patients.

Rotational thromboelastometry parameters as predicting factors for bleeding in immune thrombocytopenic purpura

OBJECTIVE/BACKGROUND

Patients with immune thrombocytopenic purpura (ITP) often present with a severe reduction in platelet counts and suffer from an increased risk of bleeding. However, platelet counts do not accurately predict bleeding risk in these patients.

METHODS

We thereby conducted a case series prospective study to compare the ability to predict hemorrhage in ITP patients between platelet counts and various rotational thromboelastometry (ROTEM) parameters.

RESULTS

The inclusion criteria for patients diagnosed with acute, persistent, and chronic ITP were platelet counts of <30 × 10⁹/L and no clinically significant bleeding (grade ≥ 2 according to the WHO Bleeding Scale) at the beginning of the study. After 24 hours of follow-up, of the 45 enrolled patients, 14 (31.1%) experienced clinically significant bleeding. The mean platelet counts of patients with and without clinically significant bleeding were not statistically different (p = .09). However, the mean EXTEM maximum clot firmness (MCF), EXTEM A10, EXTEM area under the curve (AUC), and platelet maximum clot elasticity (MCE) values of the two groups were statistically different (p < .05). There was also a significant difference in IPF values between these two groups (p < .05.) CONCLUSION: Results obtained from this preliminary study demonstrate that ROTEM parameters might be useful in predicting factors for hemorrhage in ITP patients. Future studies with a larger sample size is warranted to confirm our findings, which will allow prompt and effective bleeding management in ITP patients.

Predictive value of thromboelastography parameters combined with antithrombin III and D-Dimer in patients with recurrent spontaneous abortion

PROBLEM

To investigate the value of thromboelastography (TEG) combined with antithrombin III (AT-III) and D-Dimer in predicting the occurrence of recurrent spontaneous abortion (RSA).

METHOD OF STUDY

One hundred and five RSA patients and 40 fertile women were enrolled. The subjects were subjected into four groups: group 1 (40 fertile women), group 2 (58 women with 2 abortions), group 3 (30 women with 3 abortions), and group 4 (17 women with four abortions). TEG was conducted on all subjects. Clotting time, reaction time, angle degree, coagulation index, and maximum amplitude were measured. The levels AT-III, D-Dimer, platelet counts, and fibrinogen concentration were determined. The ROC curve analysis was done using MedCalc software to analyse the diagnosis accuracy of the parameters of interest and the combined approach.

RESULTS

The AT-III level in all group 4 was significantly lower than in fertile women. The D-Dimer concentration, platelet count, and MA in patients with four prior abortions were significantly higher than the other three groups. CI and fibrinogen concentration in patients with four prior pregnancy losses were significantly higher than group 1. The ROC curves suggested that combined use of CI, MA, AT-III, and D-Dimer was with the highest accuracy 92.8%, thus predicting the most accurate diagnosis for RSA.

CONCLUSION

Recurrent spontaneous abortion is associated with abnormal coagulation and anticoagulation. TEG combined with detection of AT-III and D-Dimer levels can distinguish patient with RSA from those with normal fertility and highly possibly predict the occurrence of RSA.

Multiple electrode aggregometry and thromboelastography in thrombocytopenic patients with haematological malignancies

BACKGROUND

In thrombocytopenic patients better assessment of bleeding risk than that provided by platelet count alone is required. Multiplate® aggregometry and thromboelastography (TEG) could be used, but information on their role in such patients is limited. The primary aim of this study was to investigate the feasibility of Multiplate® analyses in patients with haematological malignancies. A secondary aim was to explore whether a multiple logistic regression model combining Multiplate®, TEG, clinical and laboratory variables was associated with risk of bleeding.

MATERIALS AND METHODS

This was an exploratory, prospective observational study of thrombocytopenic patients with haematological malignancies. Total platelet count (TPC), white blood cell count, C-reactive protein (CRP) level, temperature and bleeding status were recorded daily. TEG and Multiplate® analyses with four agonists were performed on weekdays.

RESULTS

Ten patients were enrolled into the study. The median number of days in a study period was 21. Bleeding was observed on 64 of 298 study days. TPC <20×109/L and <10×109/L occurred on 119 and 25 days, respectively. When TPC was <33×109/L, many samples showed no aggregation, regardless of bleeding status. Despite this, the odds of World Health Organization (WHO) grade 2 bleeding decreased significantly as aggregation increased and Multiplate® had a negative predictive value (NPV) of 96% and a positive predictive value (PPV) of 19% for significant bleeding. In the multiple logistic regression model collagen-activated Multiplate® aggregation, TEG angle, TEG reaction time and CRP significantly affected the odds of WHO grade 2 bleeding. The combined model had a NPV of 99% and a PPV of 19%.

DISCUSSION

Our findings suggest that the markers of platelet function and haemostasis provided by Multiplate® aggregometry and TEG may add information to support prediction of bleeding, although platelet count still remains the most accessible analysis for routine testing.

A comparison of global coagulation assays between normal controls and patients with thrombocytopenia

INTRODUCTION

Some patients with thrombocytopenia may be at risk of bleeding although quantitative platelet count is not always a sufficient predictive factor. Global coagulation assays such as thromboelastography (TEG^® ), calibrated automated thrombogram (CAT) and overall haemostatic potential (OHP) may provide a better assessment of an individual's haemostatic profile.

METHODS

Blood samples were collected from thrombocytopenic patients. TEG^® was performed on citrated whole blood, while CAT and OHP were performed on platelet-poor plasma. Results were compared to our previously collected normal controls.

RESULTS

Fifty-eight participants (24 immune thrombocytopenia, 34 chemotherapy/malignancy-related) with mean age of 57.5 years were recruited. Compared to normal controls, thrombocytopenic participants had comparable maximum amplitude but reduced clot lysis (0.0% vs 0.6%; P < 0.001) on TEG^® with reduced endogenous thrombin potential on CAT (1252.2 vs 1353.0 nmol/L/min; P = 0.040). No differences were seen in the OHP parameters. TEG^® showed significant difference between marked and mild thrombocytopenia groups with minimal differences seen on CAT and OHP. Those with marked thrombocytopenia showed reduced maximum amplitude (47.2 vs 57.8 mm; P = 0.002) as expected while participants with mild thrombocytopenia (platelet count 100-150 × 10⁹ /L) paradoxically demonstrated increased maximum amplitude (66.4 vs 57.8 mm; P < 0.001).

CONCLUSION

Global coagulation assays, particularly TEG^® , can detect subtle differences in coagulation in thrombocytopenic patients. While patients with marked thrombocytopenia showed reduced maximum amplitude, patients with mild thrombocytopenia appear to paradoxically show increased maximum amplitude, suggesting compensatory activity within the coagulation pathway which may in part explain why not all thrombocytopenic patients have bleeding complications.

The quality of platelet concentrates related to corrected count increment: linking in vitro to in vivo

BACKGROUND

Storage of platelet concentrates (PCs) results in reduced recovery and survival of transfused platelets (PLTs). Upon storage PLTs develop storage lesion that can be monitored by several laboratory tests. However, correlation of these descriptive tests with corrected count increments (CCIs), a marker frequently used to establish the effectiveness of PLT transfusions, is limited or unknown. This study investigated to what extent a functional test or a combined in vitro rating score improves the correlation of laboratory tests with 1-hour CCI.

STUDY DESIGN AND METHODS

PCs were analyzed using six different laboratory tests (n = 123) before transfusion in a prophylactic setting to 74 hematooncologic patients. Linear regression and Spearman correlation were used to determine associations between descriptive (either separately or combined in an in vitro rating score) or functional test results and 1-hour CCIs obtained after transfusion.

RESULTS

CD62P expression (r = -0.45), annexin V binding (r = -0.36), the updated in vitro rating score (r = 0.50), and PLT responsiveness after thrombin receptor activator for peptide-6 (TRAP) (r = 0.43-0.57) or adenosine diphosphate stimulation (r = 0.11-0.51) significantly correlated to 1-hour CCIs obtained after transfusion, whereas lactate concentration, ThromboLUX score, and thromboelastography measurements did not. The strongest correlations were observed for in vitro rating score and PLT responsiveness after TRAP stimulation and these tests could explain 24 and 33% of the observed variation in 1-hour CCI, respectively.

CONCLUSION

Combining descriptive markers in one in vitro rating score improved correlation to 1-hour CCI compared to the tests separately. Of all tests investigated, mean PLT responsiveness after TRAP stimulation showed the strongest clinical correlation and was best able to predict the 1-hour CCI.

The Role of Thromboelastography in Pediatric Patients with Sinusoidal Obstructive Syndrome Receiving Defibrotide

Sinusoidal obstructive syndrome (SOS) is a potentially fatal form of hepatic injury after hematopoietic stem cell transplantation. Patients can develop liver dysfunction, portal hypertension, ascites, coagulopathies, and multisystem organ failure. The mortality rate of severe SOS has been reported as high as 98% by day 100 after transplantation. Defibrotide, which is now approved for the treatment of SOS, has significantly decreased mortality. Defibrotide is a polynucleotide with profibrinolytic, anti-ischemic, and anti-inflammatory activity. These properties can increase the risk of life-threatening bleeding in this patient population. Previous protocols have suggested maintaining international normalized ratio ≤ 1.5, platelets > 30 k/uL, and fibrinogen ≥ 150 mg/dL to minimize this risk of bleeding. However, this can be challenging in fluid-sensitive patients with SOS. Thromboelastography (TEG) is a functional assay that evaluates the balance of procoagulant and anticoagulant proteins. In this series, TEG was used to guide defibrotide therapy as well as blood product transfusions in SOS patients with abnormal coagulation studies. Each patient recovered from SOS and had no bleeding complications. A randomized clinical trial is the next step in supporting the use of TEG in SOS patients with abnormal coagulation studies receiving defibrotide therapy.