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PLATELET AGGREGATION STUDY OF ESSENTIAL THROMBOCYTHEMIA TREATED WITH ANAGRELIDE
Author(s):
Yasushi Hiramatsu
,
Yasushi Hiramatsu
Affiliations:
Department of Hematology and Oncology,Japanese Red Cross Society Himeji Hospital,Himeji,Japan
Keiko Furukawa
,
Keiko Furukawa
Affiliations:
Department of Pathology and Clinical Laboratory,Japanese Red Cross Society Himeji Hospital,Himeji,Japan
Kentaro Mizuhara
,
Kentaro Mizuhara
Affiliations:
Department of Hematology and Oncology,Japanese Red Cross Society Himeji Hospital,Himeji,Japan
Tasuku Sakayori
,
Tasuku Sakayori
Affiliations:
Hemostasis Product Engineering,Sysmex Corporation,Kobe,Japan
Yuki Fujiwara
,
Yuki Fujiwara
Affiliations:
Department of Hematology and Oncology,Japanese Red Cross Society Himeji Hospital,Himeji,Japan
Naoya Mochizuki
,
Naoya Mochizuki
Affiliations:
Department of Hematology and Oncology,Japanese Red Cross Society Himeji Hospital,Himeji,Japan
Shiro Kubonishi
,
Shiro Kubonishi
Affiliations:
Department of Hematology and Oncology,Japanese Red Cross Society Himeji Hospital,Himeji,Japan
Yutaka Komiyama
Yutaka Komiyama
Affiliations:
Hemostasis Product Engineering,Sysmex Corporation,Kobe,Japan
(Abstract release date: 05/18/17) EHA Library. Hiramatsu Y. 05/18/17; 182756; PB2042
Yasushi Hiramatsu
Yasushi Hiramatsu
Contributions
PDF Abstract
Abstract

Abstract: PB2042

Type: Publication Only

Background

Essential thrombocythemia (ET) is a myeloproliferative neoplasm characterized by thrombocytosis and abnormal megakaryocyte proliferation. Patients with elevated platelet count are considered to be a high-risk group for thromboembolic and/or hemorrhagic complications. In Japan, anagrelide treatment was recently approved for the 1st line as a cell reduction therapy on ET. Even now, there are few study whether the risk of thrombosis has decreased after anagrelide treatment. Moreover, the platelet count problem uncertainty remains what is the best practice to follow when the platelet count in platelet-rich plasma (PRP) exceeds about 600 x109/L, in the recent recommendations for the standardization of light transmission aggregometry by the platelet physiology subcommittee of Scientific and Standardization Committee /International Society of Thrombosis and Hemostasis.

Aims

The aim of this study was to characterize the platelet aggregation (PA) in patients with ET. We would also clarify whether there were any changes of hemostatic side effect and platelet aggregability before and after treatment with anagrelide.

Methods
This study has been conducted with blood sample obtained from six healthy subjects, compared to 18 consecutive patients with ET. None of the patients was taking anticoagulants or cytoreductive agents. We also studied six anagrelide-treated patients with ET. Whole blood aggregometry (WBA) and LTA using PRP were performed. ADP-induced PA or collagen-induced PA used natural count PRP and platelet count adjusted PRP with platelet-poor plasma. Data were compared in the groups using the Tukey-Kramer test. This study was approved by the Ethical committee of our hospital. All study procedures were performed in accordance with the Declaration of Helsinki.

Results
The result of WBA was not obtained, because the filter was obstructed by giant platelets. In the natural PRP, even over 900x109/L, the platelet aggregability was markedly increased compared with the control (ADP-induced PA: p=0.023, collagen-induced PA: p=0.001), but, was not significantly different (ADP-induced PA: p=0.703, collagen-induced PA: p=0.986) in the count adjusted PRP. These results were not confirmed in cases with platelet counts of less than 600x109/L. There was no decrease in platelet aggregation before and after treatment with anagrelide (ADP-induced PA: p=0.3403, collagen-induced PA: p=0.514).　

Conclusion
In the ET patients with platelet counts more than 900x109/L, the platelet aggregation by LTA with natural count PRP was remarkably accelerated and this data seemed to reflect the disease state. Although treatment with anagrelide showed cyto-reductive effect without any hemorrhagic complication in patients with ET, it did not fully reduce platelet aggregability.

Session topic: 16. Myeloproliferative neoplasms - Clinical

Keyword(s): Platelet aggregation, Essential Thrombocytemia, Anagrelide

Abstract: PB2042

Type: Publication Only

Background

Essential thrombocythemia (ET) is a myeloproliferative neoplasm characterized by thrombocytosis and abnormal megakaryocyte proliferation. Patients with elevated platelet count are considered to be a high-risk group for thromboembolic and/or hemorrhagic complications. In Japan, anagrelide treatment was recently approved for the 1st line as a cell reduction therapy on ET. Even now, there are few study whether the risk of thrombosis has decreased after anagrelide treatment. Moreover, the platelet count problem uncertainty remains what is the best practice to follow when the platelet count in platelet-rich plasma (PRP) exceeds about 600 x109/L, in the recent recommendations for the standardization of light transmission aggregometry by the platelet physiology subcommittee of Scientific and Standardization Committee /International Society of Thrombosis and Hemostasis.

Aims

The aim of this study was to characterize the platelet aggregation (PA) in patients with ET. We would also clarify whether there were any changes of hemostatic side effect and platelet aggregability before and after treatment with anagrelide.

Methods
This study has been conducted with blood sample obtained from six healthy subjects, compared to 18 consecutive patients with ET. None of the patients was taking anticoagulants or cytoreductive agents. We also studied six anagrelide-treated patients with ET. Whole blood aggregometry (WBA) and LTA using PRP were performed. ADP-induced PA or collagen-induced PA used natural count PRP and platelet count adjusted PRP with platelet-poor plasma. Data were compared in the groups using the Tukey-Kramer test. This study was approved by the Ethical committee of our hospital. All study procedures were performed in accordance with the Declaration of Helsinki.

Results
The result of WBA was not obtained, because the filter was obstructed by giant platelets. In the natural PRP, even over 900x109/L, the platelet aggregability was markedly increased compared with the control (ADP-induced PA: p=0.023, collagen-induced PA: p=0.001), but, was not significantly different (ADP-induced PA: p=0.703, collagen-induced PA: p=0.986) in the count adjusted PRP. These results were not confirmed in cases with platelet counts of less than 600x109/L. There was no decrease in platelet aggregation before and after treatment with anagrelide (ADP-induced PA: p=0.3403, collagen-induced PA: p=0.514).　

Conclusion
In the ET patients with platelet counts more than 900x109/L, the platelet aggregation by LTA with natural count PRP was remarkably accelerated and this data seemed to reflect the disease state. Although treatment with anagrelide showed cyto-reductive effect without any hemorrhagic complication in patients with ET, it did not fully reduce platelet aggregability.

Session topic: 16. Myeloproliferative neoplasms - Clinical

Keyword(s): Platelet aggregation, Essential Thrombocytemia, Anagrelide

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