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Table of Contents
CASE REPORT
Year : 2020  |  Volume : 5  |  Issue : 1  |  Page : 51-54

Adjusting antithrombotic therapy after stent implantation for acute myocardial infarction in a patient with very low platelet


Department of Cardiology, The Second Affiliated Hospital of Soochow University, Suzhou, China

Date of Submission18-Apr-2019
Date of Acceptance06-Dec-2019
Date of Web Publication4-Apr-2020

Correspondence Address:
Dr. Liang-Ping Zhao
Department of Cardiology, The Second Affiliated Hospital of Soochow University, 1055 Sanxiang Road, Suzhou 215004
China
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/cp.cp_1_20

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  Abstract 

A 76-year-old woman presented with non-ST-elevation myocardial infarction. Platelet count was 10×109/L. Bone marrow cytology and platelet antibody testing 9 months earlier suggested refractory immune thrombocytopenia (unresponsive to glucocorticoid and γ-globulin). The patient stabilized after treatments that included clopidogrel, statin, nitrate, and conventional anti-heart failure drugs, but heart failure persisted. Nine days later, angiography revealed 90% occlusion in the left anterior descending artery, and the patient received a zotarolimus-eluting stent. Upon discharge from the hospital, the patient started to receive clopidogrel, statin, β-blocker, and spironolactone. The patient remained free from the symptoms and reported no signs of bleeding for the next 8 months until she was readmitted for pneumonia and heart failure. Platelet count at this time was 2×109/L. Clopidogrel was discontinued. Ginkgo leaf tablets (an herbal medication with reported activity against platelet aggregation) were initiated. Subsequent follow-up visits were unremarkable, until 16 months after percutaneous coronary intervention, when platelet count decreased to 1×109/L. Ginkgo leaf tablet was discontinued. In summary, the evidence supporting the efficacy of clopidogrel at shorter than the recommended 12 months is anecdotal, but the need to adjustment dual antiplatelet therapy in patients with very low platelet count is solid.

Keywords: Acute myocardial infarction, antiplatelet therapy, prognosis


How to cite this article:
Zhao LP, Gu XS, You T, Xu WT. Adjusting antithrombotic therapy after stent implantation for acute myocardial infarction in a patient with very low platelet. Cardiol Plus 2020;5:51-4

How to cite this URL:
Zhao LP, Gu XS, You T, Xu WT. Adjusting antithrombotic therapy after stent implantation for acute myocardial infarction in a patient with very low platelet. Cardiol Plus [serial online] 2020 [cited 2020 May 27];5:51-4. Available from: http://www.cardiologyplus.org/text.asp?2020/5/1/51/281937




  Introduction Top


Major guidelines recommend dual antiplatelet therapy (DAPT) for at least 12 months after percutaneous coronary intervention (PCI) with stent implantation.[1],[2] Whether such a recommendation is appropriate in patients with very low platelet count, and hence, very high risk of bleeding is unknown. Here, we present a case in which clopidogrel was discontinued 8 months after PCI due to very low platelet count (2×109/L). The management and outcome are summarized below.


  Case Presentation Top


A 76-year-old woman presented with recurrent chest pain and shortness of breath for 2 weeks. A diagnosis of non-ST-elevation myocardial infarction was established based on ST-segment depression and elevated cardiac troponin I level. Past history included hypertension for 20 years and thrombocytopenia for 30 years, but no diabetes, dyslipidemia, or smoking. She disclosed “immune thrombocytopenia,” established with bone marrow cytology, immunology panel, and platelet antibody test 9 months earlier; treatment with glucocorticoid and γ-globulin was not effective.

Clinical findings

A routine blood test showed a platelet count of 10×109/L, red blood cell count of 2.66×1012/L, hemoglobin of 83 g/L, white blood cell count of 5.8×109/L, low-density lipoprotein cholesterol of 1.32 mmol/mL, and serum creatinine of 53 μmol/L. Adenosine diphosphate-induced platelet aggregation rate was under the detection limit. The coagulation test showed a prothrombin time of 14.5 s, partial thromboplastin time of 30.9 s, thrombin time of 16.8 s, and D-dimer of 2.41 μg/ml. Echocardiography showed 48% left ventricular ejection fraction (LVEF) and akinesia of the apex/anteroseptum. End-diastolic diameter of the left ventricle was 58 mm.



Therapeutic intervention

The patient received clopidogrel, statin, nitrate, β-blocker, spironolactone, furosemide, and milrinone. The platelet count was monitored [Table 1]. Chest pain gradually subsided but left heart failure persisted. Coronary angiography was conducted 9 days later. Bivalirudin was used instead of heparin due to a high risk of bleeding (HAS-BLED score at 3 and CRUSADE score at 43).
Table 1: Platelet count and antithrombotic agent at various time points

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Coronary angiography showed 90% occlusion of the proximal segment of the left anterior descending artery with slow blood flow, as well as mild stenosis in the right coronary artery [Figure 1]a, [Figure 1]b, [Figure 1]c. Blood flow did not increase upon balloon dilation but increased after the implantation of a zotarolimus-eluting stent (ZES) [Figure 1]d. ST segment normalized after PCI, and left heart failure was alleviated. Five days later, the patient was discharged and instructed to take clopidogrel (75 mg/day), statin, β-blocker, spironolactone, and lansoprazole. Aspirin was not used because of the very low platelet count.
Figure 1: (a) Angiography at the caudal position showing severe stenosis of the left anterior descending coronary artery at caudal position. (b) Angiography at the cranial position showing severe stenosis of the left anterior descending coronary artery. (c) Angiography showing mild stenosis of the right coronary artery. (d) The left anterior descending coronary artery after stent implantation

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Follow-up and outcome

At the 3-month follow-up, the patient reported no shortness of breath or bleeding. LVEF was 62%; end-diastolic diameter of the left ventricle was 47 mm. Platelet count remained stable at 9×109 L. Treatment with clopidogrel continued. The 6-month follow-up was not remarkable. Eight months after PCI, she developed pneumonia and heart failure (39% LVEF). Platelet count decreased to 2×109/L. The patient received platelet transfusion (10 units). Clopidogrel was discontinued. Ginkgo leaf tablets (an herbal medication with reported antiplatelet activity) were added (9.6 mg, three times/day). The patient's pneumonia was cured by the use of cephalosporin. Other pharmacotherapies, including statin, β-blockers, and spironolactone, were continued. At the 12-month follow-up, platelet count was 6×109/L, and the patient reported no signs of acute coronary syndrome or bleeding. At the 16-month follow-up, platelet count was 1×109/L, with 65 g/L hemoglobin, but the patient had no signs of bleeding. She received platelet and red blood cell transfusion. Ginkgo leaf tablet was discontinued.


  Discussion Top


Both the European and US Guidelines recommend at least 12-month DAPT in patients receiving coronary artery stent.[1],[2] The index patient received clopidogrel despite the relatively low platelet count (9×109/L) after the PCI. No signs of intra-stent thrombosis or bleeding were noticed for 8 months.

Clinical studies and rat experiments showed that Ginkgo leaf tablets could inhibit platelet aggregation and prevents thrombosis by improving microcirculation and cell metabolism in the brain and heart.[3],[4],[5] Indications approved by the Chinese Food and Drug Administration include ischemic stroke, coronary artery disease, and other microcirculatory dysfunction diseases. In the index case, the patient received Ginkgo leaf tablets after discontinuing clopidogrel when platelet count decreased to 2×109/L 8 months after PCI. The patient apparently remained free from intrastent thrombosis on Ginkgo leaf tablets for the next 8 months.

The duration of the DAPT after PCI depends critically on reendothelialization.[6] Accumulating evidence suggests that reendothelialization is (1) generally completed within 6 months after stent implantation and (2) faster with ZESs than with sirolimus-eluting stents, everolimus-eluting stents, or paclitaxel-eluting stents.[7],[8],[9] A study using optical coherence tomography (OCT) showed that ZESs were completely covered with neointima in 75% of 3 months after the implantation; only 0.9%-4.3% of the struts were uncovered in the remaining patients.[7] A more recent OCT study showed that the proportion of uncovered struts at 6 months after ZES implantation was only 0.4%.[8] Based on these findings, the duration of DAPT after PCI could be shortened to probably 6 months after ZES implantation. Indeed, several ongoing trials are investigating the efficacy and adverse events DAPT at <12 months.

As a case report, we could not assess the relationship between early clopidogrel withdrawal and lack of thrombotic events. Furthermore, to what degree Ginkgo leaf tablets contributed to the lack of thrombotic events, if any, remains to be further investigated.

Consent

The authors confirm that written consent for submission and publication of this case report, including images and associated text, has been obtained from the patient in line with the COPE guideline.

Financial support and sponsorship

This study was supported by the Suzhou Science and Technology Development Program Guidance Project Fund (#SYSD2013093), Youth Natural Science Fund of Soochow University (#SDY2013A32), Research Fund of the Second Affiliated Hospital of Soochow University (#SDFEYGJ1405), and Xinxin Heart (SIP) Foundation (#2019-CCA-ACCESS-058).

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Valgimigli M, Bueno H, Byrne RA, Collet JP, Costa F, Jeppsson A, et al. 2017 ESC focused update on dual antiplatelet therapy in coronary artery disease developed in collaboration with EACTS: The task force for dual antiplatelet therapy in coronary artery disease of the European Society of Cardiology (ESC) and of the European Association for Cardio-Thoracic Surgery (EACTS). Eur Heart J 2018;39:213-60.  Back to cited text no. 1
    
2.
Bittl JA, Baber U, Bradley SM, Wijeysundera DN. Duration of dual antiplatelet therapy: A systematic review for the 2016 ACC/AHA guideline focused update on duration of dual antiplatelet therapy in patients with coronary artery disease: A report of the American College of Cardiology/American Heart Association task force on clinical practice guidelines. J Am Coll Cardiol 2016;68:1116-39.  Back to cited text no. 2
    
3.
Zhao Y, Yu J, Liu J, An X. The role of liuwei dihuang pills and ginkgo leaf tablets in treating diabetic complications. Evid Based Complement Alternat Med 2016;2016:1-8.  Back to cited text no. 3
    
4.
Mantle D, Wilkins RM, Gok MA. Comparison of antioxidant activity in commercial ginkgo biloba preparations. J Altern Complement Med 2003;9:625-9.  Back to cited text no. 4
    
5.
Lu ZQ, Deng YJ, Lu JX. Effect of aloe polysaccharide on caspase-3 expression following cerebral ischemia and reperfusion injury in rats. Mol Med Rep 2012;6:371-4.  Back to cited text no. 5
    
6.
Adriaenssens T, Joner M, Godschalk TC, Malik N, Alfonso F, Xhepa E, et al. Optical coherence tomography findings in patients with coronary stent thrombosis: A report of the PRESTIGE Consortium (Prevention of Late Stent Thrombosis by an Interdisciplinary Global European Effort). Circ 2017;136:1007-21.  Back to cited text no. 6
    
7.
Fujii K, Kawasaki D, Oka K, Akahori H, Fukunaga M, Sawada H, et al. Endothelium-dependent coronary vasomotor response and neointimal coverage of zotarolimus-eluting stents 3 months after implantation. Heart 2011;97:977-82.  Back to cited text no. 7
    
8.
Nakata T, Fujii K, Fukunaga M, Shibuya M, Kawai K, Kawasaki D, et al. Morphological, functional, and biological vascular healing response 6 months after drug-eluting stent implantation: A randomized comparison of three drug-eluting stents. Catheter Cardiovasc Interv 2016;88:350-7.  Back to cited text no. 8
    
9.
Murase S, Suzuki Y, Yamaguchi T, Matsuda O, Murata A, Ito T. The relationship between re-endothelialization and endothelial function after DES implantation: Comparison between paclitaxcel eluting stent and zotarolims eluting stent. Catheter Cardiovasc Interv 2014;83:412-7.  Back to cited text no. 9
    


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