Home About us Editorial board Ahead of print Current issue Search Archives Submit article Instructions Subscribe Contacts Login 
  • Users Online:221
  • Home
  • Print this page
  • Email this page


 
 Table of Contents  
ORIGINAL ARTICLE
Year : 2020  |  Volume : 5  |  Issue : 2  |  Page : 202-205

Utility of thromboelastography platelet mapping in bleeding disorders – An experience from Eastern India


1 Department of Transfusion Medicine, The Mission Hospital, Durgapur; Department of Transfusion Medicine, Tata Medical Center, Kolkata, West Bengal, India
2 Department of Clinical Hematology, The Mission Hospital, Durgapur, West Bengal, India

Date of Submission08-Aug-2020
Date of Decision01-Sep-2020
Date of Acceptance15-Sep-2020
Date of Web Publication13-Nov-2020

Correspondence Address:
Suvro Sankha Datta
Department of Transfusion Medicine, The Mission Hospital, Durgapur; Department of Transfusion Medicine, Tata Medical Center, Kolkata, West Bengal
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/GJTM.GJTM_75_20

Rights and Permissions
  Abstract 


Background and Objectives: Thromboelastography platelet mapping (TEG-PM) is primarily used to monitor the effectiveness of antiplatelet medications by assessing the inhibition of thromboxane A2 and adenosine diphosphate (ADP) receptors. The objective of this study was to understand the utility of TEG-PM assay in suspected cases of bleeding disorders. Materials and Methods: A total of 20 suspected cases of bleeding disorders were tested by TEG-PM assay as a primary screening test. The percentage of platelet aggregation to agonist was calculated by: ([MAADP/AA– MAFibrin]/[MAThrombin– MAFibrin] × 100) and inhibition by: (100% – % aggregation). The cutoff was defined as >50% inhibition for each agonist. Light transmittance aggregometry (LTA) was performed when the inhibition was >50% both with ADP and arachidonic acid (AA). Results: Ten out of 20 patients were showing an inhibition >50% with ADP and 5 among 20 had an inhibition >50% with AA. Among four patients who had >50% inhibition with both agonists, two cases were diagnosed as Glanzmann's thrombasthenia by LTA and one case was diagnosed as Wiskott–Aldrich syndrome by genetic analysis. Final diagnosis was not made in one case as LTA was inconclusive. Conclusion: We believe that TEG-PM assay may be introduced in preliminary algorithm for the diagnosis of bleeding disorders where facility such as LTA is not easily available.

Keywords: Bleeding disorders, platelet-mapping, thromboelastography


How to cite this article:
Datta SS, Dibyendu D. Utility of thromboelastography platelet mapping in bleeding disorders – An experience from Eastern India. Glob J Transfus Med 2020;5:202-5

How to cite this URL:
Datta SS, Dibyendu D. Utility of thromboelastography platelet mapping in bleeding disorders – An experience from Eastern India. Glob J Transfus Med [serial online] 2020 [cited 2020 Nov 25];5:202-5. Available from: https://www.gjtmonline.com/text.asp?2020/5/2/202/300635




  Introduction Top


Thromboelastography (TEG) is clinically used to reveal the nature of coagulopathy in multiple clinical conditions and to guide the appropriate transfusion protocol in various clinical settings.[1] TEG platelet mapping (TEG-PM) is a novel modification of conventional TEG that employs antagonists of coagulation cascade-meditated thrombosis in concert with platelet agonists such as arachidonic acid (AA) and adenosine diphosphate (ADP) to determine the level of platelet inhibition.[2] The TEG-PM assay is commonly used to monitor the effectiveness of antiplatelet medications by assessing the inhibition of thromboxane A2 (TxA2) and ADP receptors present over the platelets. Traditional platelet assessment in bleeding disorders has included the platelet count, which is a quantitative but not qualitative assay, and the bleeding time, which has the limitations of inconsistency and poor sensitivity.[3] Platelet function testing (PFT) is done to identify congenital and acquired platelet function defects which can be performed by multiple methods, but light transmittance aggregometry (LTA) is still considered as “gold standard assay” among all. The currently available other PFT assays include VerifyNow, TEG-PM, multiple platelet function analyzer (Multiplate), platelet function assay (PFA)-100, and vasodilator-stimulated protein flow cytometry.[4]

Aims and objectives

The objective of this study was to understand the utility of TEG-PM assay in suspected cases of bleeding disorders.


  Materials and Methods Top


This was a retrospective, single-center cohort study, where 20 suspected cases of bleeding disorders were tested by TEG-PM assay as a primary screening test. All these patients attended the hematology outpatient department from June 2017 to June 2019.

Ethical clearance

Institutional review board (ECR/587/Inst/WB/2014/RR-17) approval was obtained for this study. Informed consent was taken from each patient before the assay.

All patients with clinical bleeding manifestations and platelet count >100 × 109/L were included in this study. The exclusion criteria were known case of diabetes mellitus and those who had a recent history of antiplatelet drug intake, platelet count < 100 × 109/L, prothrombin time >1.5 times of control, and hematocrit < 30%. All patients were tested by TEG-PM assay during their first visit to the hospital.

Blood samples were obtained from each patient and transferred to separate vacutainer blood collecting tubes (BD Medical Systems) containing 3.2% trisodium citrate or lithium heparin. After discarding the first 2–3 mL of blood, the vacutainer tubes were filled to capacity and gently inverted 3–5 times to ensure complete mixing of the anticoagulant. After collection, samples were immediately sent to the transfusion medicine department for TEG-PM analysis. Blood was analyzed in the coagulation laboratory by trained personnel within an hour of receiving the blood sample as per the manufacturer instructions (Haemoscope Corporation; TEG Guide to Platelet Mapping; Monitor Antiplatelet Therapy; 2008). Both analyzer (series 5000) and the reagents were from Haemoscope Corporation (Niles, Illinois, USA). TEG parameters studied were reaction time (R) – time to initial fibrin formation up to 2 mm; K time (K) – time to clot formation up to 20 mm; alpha angle (α) – speed of clot formation; and maximum amplitude (MA) – measurement of clot strength. The normal reference values of TEG parameters (as provided by the manufacturer) for kaolin-activated citrated samples were taken as R = 2–8 min, K = 1–3 min, alpha (α) angle = 55°–78°, and MA = 51–69 mm. Heparin was used as an anticoagulant to eliminate thrombin activity in the sample during assay. Reptilase and activated factor XIII (activator F) were used to generate a cross-linked fibrin clot to isolate the fibrin contribution in clot strength.[2] For maximal clot strength (MAThrombin), 1 mL of citrate stabilized blood was transferred to a vial containing kaolin and mixed five times by gentle inversion. Kaolin-activated blood (340 μL) was added to a TEG cup containing 20 μL of 0.2 M CaCl2. As MA, which is representing the maximal clot strength, can be ascertained by the binding of activated platelets to a fibrin mesh, 360 μL of heparinized blood was added to 10 μL of activator F (reptilase and factor XIIIa) and the contribution of each fibrin meshwork to clot strength (MAFibrin) was assessed. The contribution of P2Y12 receptor or cyclooxygenase pathways to the clot formation can be measured by the addition of the appropriate agonist, ADP or AA.[2] Therefore, ADP and AA, respectively, were added to activator F to measure the degree of ADP receptor and TxA2-induced platelet aggregation. Heparinized blood (360 μL) was added to a TEG cup in the presence of the activator F and agonist, 10 μL ADP (2 μM, final concentration) yielding the MAADP or 10 μL AA (1 μM, final concentration) for the MAAA. Percentage of platelet inhibition was defined by the extent of nonresponse of the platelet ADP or TXA2 receptor to the exogenous ADP and AA as measured by TEGMA. The percentage of platelet aggregation to agonist was calculated by: ([MAADP/AA– MAFibrin]/[MAThrombin– MAFibrin] × 100) and % inhibition = (100% − % aggregation). Calculation was performed by the TEG-PM software to get the percentage of platelet inhibition in patients. The cutoff was defined as >50% inhibition in the presence of both ADP and AA. LTA or genetic analysis was performed at outside referral center as confirmatory tests when the inhibition was >50% in the presence of both the agonists.

Statistical analysis

All data were recorded and analyzed using Microsoft Excel statistics software package (Microsoft Office, USA; 2013), and the results were compared with the LTA interpretations whenever available to observe the correlation between two methods.


  Results Top


[Table 1] summarizes all details regarding patients and tests performed. Fifty percent (10/20) of the patients were showing an inhibition >50% with ADP and 25% (5/20) patients were showing an inhibition >50% with AA. LTA was performed in four patients who had >50% inhibition both with AA and ADP. Among them, two were diagnosed as Glanzmann's thrombasthenia by LTA and one was diagnosed as Wiskott–Aldrich syndrome (WAS) by genetic analysis [Figure 1]. Final diagnosis was not made in one case as LTA result was found inconclusive.
Table 1: Details of patients and tests

Click here to view
Figure 1: Thromboelastography platelet mapping graphs in Glanzmann's thrombasthenia and Wiskott–Aldrich syndrome

Click here to view



  Discussion Top


TEG evaluates clot formation and fibrinolysis dynamically by continuously measuring and graphically displaying the changes in viscoelasticity at all stages of the developing and resolving clot. It is recommended to use a reference range suitable for each clinical condition for better interpretation of the results by TEG as well as to set an in-house reference range for individual centers.[5] There is no reference range available for TEG-PM assay in bleeding disorders because it is not routinely used as a screening test for this purpose.[6] During the prestudy validation experience with TEG-PM assay among healthy blood donors in our center, for the platelet TxA2 receptor, the inhibition was found 1% (range 0%–2%), and for the ADP receptor, the inhibition was found 4% (range 0%–8%) maintaining the intra-assay and inter-assay coefficient of variance within 10% for the test. The tests such as LTA or PFA-100 are confirmatory for cases of bleeding disorders due to platelet dysfunctions, but they are not widely available in our region and sample transportation time is critical for those tests during outsourcing of samples to the nearest referral laboratory. Therefore, we decided to use our existing TEG machine and took an initiative to perform nonconventional test such as TEG-PM assay for cases of bleeding disorders to determine the utility of this assay as a screening test. During our study, two cases who had >50% inhibition both with AA and ADP were diagnosed as Glanzmann's thrombasthenia by LTA, which is in agreement with previous studies published by Callaghan et al.[7] and Ahammad et al.[8] One patient was diagnosed as a case of WAS by identifying WAS mutation during genetic analysis where the inhibition was >50% in TEG-PM assay with both the agonists. The reduced platelet function in WAS patients could be due to less surface expression of P-selectin and less activated GPIIb-IIIa over platelets membrane as concluded by Bussel et al.[9] The LTA result was found inconclusive in one case despite >50% inhibition observed with ADP and AA, which could be due to the limitation of LTA in certain cases of bleeding disorders due to platelets structural abnormalities such as those found in gray platelet syndrome.[10]

There are several limitations in this brief study including a small sample size. LTA was not performed in all the cases; therefore, sensitivity, specificity, and negative and positive predictive values of TEG-PM assay for bleeding disorder cases could not be estimated. Bleeding time was not performed during the study due to poor sensitivity of the test which could be considered as another limitation.


  Conclusion Top


TEG-PM assay may be considered in the diagnosis of bleeding disorders where facility such as LTA is not easily available. However, the small size of the study precludes any definitive directions for its use routinely. Future prospective studies comparing TEG-PM with other PFTs in bleeding disorders are required for further understanding of this apparently new test.

Statement on ethics

Institutional review board (ECR/587/Inst/WB/2014/RR-17) approval was obtained for this study. Informed consent was taken from each patient before the assay.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patients have given their consent for their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Verma A, Hemlata. Thromboelastography as a novel viscoelastic method for hemostasis monitoring: Its methodology, applications, and constraints. Glob J Transfus Med AATM 2017;2:8-18.  Back to cited text no. 1
    
2.
TEG 5000 Haemostasis Analyser: User Manual. Niles, IL, USA: Haemoscope Corporation; 2008.  Back to cited text no. 2
    
3.
Rogers RP, Levin J. A critical appraisal of the bleeding time. Semin Thromb Hemost 1990;16: 1-20.  Back to cited text no. 3
    
4.
Breet NJ, van Werkum JW, Bouman HJ, Kelder JC, Ruven HJ, Bal ET, et al. Comparison of platelet function tests in predicting clinical outcome in patients undergoing coronary stent implantation. JAMA 2010;303:754-62.  Back to cited text no. 4
    
5.
Ahammad J, Kurien A, Shastry S, Shah HH, Nayak D, Kamath A, Badagabettu S. Age- and gender-related reference ranges for thromboelastography from a healthy Indian population. Int J Lab Hematol 2020;42:180-9.  Back to cited text no. 5
    
6.
Nogami K. The utility of thromboelastography in inherited and acquired bleeding disorders. Br J Haematol 2016;174:503-14.  Back to cited text no. 6
    
7.
Callaghan MU, Chitlur MB, Lusher JM, Rajpurkar M, Fleming P. Thromboelastogram platelet mapping accurately predicts bleeding phenotype in Glanzmann thrombasthenia. Blood 2008;112:4560.  Back to cited text no. 7
    
8.
Ahammad J, Kamath A, Shastry S, Chitlur M, Kurien A. Clinico-hematological and thromboelastographic profiles in Glanzmann's thrombasthenia. Blood Coagul Fibrinolysis 2020;31:29-34.  Back to cited text no. 8
    
9.
Bussel JB, Frelinger II, Mitchell AL, Pinheiro WB, Barnard MP, Lampa MR, et al. Platelet function and response to thrombopoietin mimetics in Wiskott-Aldrich syndrome/X-linked thrombocytopenia. Blood 2010;(ASH Annual Meeting Abstracts), 116, 613. Abstract 1429.   Back to cited text no. 9
    
10.
Alessi MC, Sié P, Payrastre B. Strengths and weaknesses of light transmission aggregometry in diagnosing hereditary platelet function disorders. J Clin Med 2020;9:763.  Back to cited text no. 10
    


    Figures

  [Figure 1]
 
 
    Tables

  [Table 1]



 

Top
 
 
  Search
 
Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

 
  In this article
Abstract
Introduction
Materials and Me...
Results
Discussion
Conclusion
References
Article Figures
Article Tables

 Article Access Statistics
    Viewed182    
    Printed2    
    Emailed0    
    PDF Downloaded5    
    Comments [Add]    

Recommend this journal


[TAG2]
[TAG3]
[TAG4]