EXPRESS PUBLICATION
Aspirin resistance is associated with a high incidence of myonecrosis after non-urgent percutaneous coronary intervention despite clopidogrel pretreatment
Wai-Hong Chen, MBBS*,*,
Pui-Yin Lee, MBBS*,
William Ng, MBBS*,
Hung-Fat Tse, MD, FACC* and
Chu-Pak Lau, MD, FACC*
* Department of Medicine, The University of Hong Kong, Queen Mary Hospital, Hong Kong, China
Manuscript received October 12, 2003;
revised manuscript received November 30, 2003,
accepted December 9, 2003.
* Reprint requests and correspondence: Dr. Wai-Hong Chen, Division of Cardiology, Department of Medicine, The University of Hong Kong, Queen Mary Hospital, Hong Kong, China. whchen{at}hku.hk
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Abstract
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OBJECTIVES: We sought to investigate the effect of aspirin resistance on the incidence of myonecrosis after non-urgent percutaneous coronary intervention (PCI) among patients pretreated with clopidogrel.
BACKGROUND: Oral antiplatelet therapy using aspirin and a thienopyridine is the standard of care for preventing thrombotic complications of PCI. The effect of aspirin resistance on the outcomes of patients undergoing PCI is unknown.
METHODS: We used the Ultegra Rapid Platelet Function Assay-ASA (Accumetrics Inc., San Diego, California) to determine aspirin responsiveness of 151 patients scheduled for non-urgent PCI. All patients received a 300-mg loading dose of clopidogrel >12 h before and a 75-mg maintenance dose in the morning of the PCI. The incidence of myonecrosis was measured by creatine kinase-myocardial band (CK-MB) and by troponin I (TnI) elevations after PCI.
RESULTS: A total of 29 (19.2%) patients were noted to be aspirin-resistant. There was a significantly higher incidence of female subjects in the aspirin-resistant versus aspirin-sensitive groups. The incidence of any CK-MB elevation was 51.7% in aspirin-resistant patients and 24.6% in aspirin-sensitive patients (p = 0.006). Elevation of TnI was observed in 65.5% of aspirin-resistant patients and 38.5% of aspirin-sensitive patients (p = 0.012). Multivariate analysis revealed aspirin resistance (odds ratio [OR] 2.9; 95% confidence interval [CI] 1.2 to 6.9; p = 0.015) and bifurcation lesion (OR 2.8; 95% CI 1.3 to 6.0; p = 0.007) to be independent predictors of CK-MB elevation after PCI.
CONCLUSIONS: Despite adequate pretreatment with clopidogrel, patients with aspirin resistance as measured by a point-of-care assay have an increased risk of myonecrosis following non-urgent PCI.
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Abbreviations and Acronyms
| | ARU | = aspirin reaction unit | | CK-MB | = creatine kinase-myocardial band | | NSAID | = non-steroidal anti-inflammatory drugs | | OR | = odds ratio | | PCI | = percutaneous coronary intervention | | TnI | = troponin I |
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Early complications of percutaneous coronary intervention (PCI) are caused by arterial thrombosis at the site of vessel injury (1). More complete platelet inhibition using aspirin and a thienopyridine during PCI offers protection against ischemic complications (27). However, 8% to 45% (811) of patients do not respond to aspirin therapy as determined by different laboratory tests, and these aspirin-resistant patients are at increased risk of thrombotic events (8,1214). The contribution of aspirin, a relatively weak antiplatelet agent, to the prevention of thrombotic complications of PCI in the presence of the full effect of a thienopyridine is unknown. This study was designed to compare the incidence of myonecrosis after PCI between aspirin-resistant and aspirin-sensitive patients pretreated with clopidogrel >12 h before PCI.
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Methods
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Study population.
Consecutive patients with aspirin use of 80- to 325-mg daily for 1 week and who were scheduled for PCI were enrolled. Exclusion criteria included saphenous vein graft intervention, chronic total occlusions that could not be crossed by guidewires, preprocedural elevation of creatine kinase-myocardial band (CK-MB) or troponin I (TnI), planned use of glycoprotein IIb/IIIa inhibitors, and the use of antiplatelet drugs other than aspirin or non-steroidal anti-inflammatory drugs (NSAIDs) within two weeks of the PCI. The local ethics committee on human research approved the protocol, and all patients provided written informed consent.
Study protocol.
After collecting baseline blood samples for CK-MB, TnI, and aspirin responsiveness, all patients received an oral loading dose of 300-mg clopidogrel 12 to 24 h before the procedure. The PCI procedure was performed on the following day according to standard practice, after the patients received an additional 75-mg maintenance dose of clopidogrel. Unfractionated heparin 70 U/kg or enoxaparin 1 mg/kg was used for procedural anticoagulation at operator discretion. Following the procedure, blood samples for TnI were collected at 12 to 24 h, whereas those for CK-MB were collected at 6 to 8 h. If CK-MB was elevated, serial measurements every 8 h were obtained and the peak level was recorded. The CK-MB was considered elevated if 16 U/l, which was further subdivided into 1 to 3 x (16 to 48 U/l), 3 to 5 x (49 to 80 U/l), and >5 x (>80 U/l) normal. A TnI value of 2.0 ng/ml was considered elevated. Aspirin-induced platelet inhibition was measured using a commercially available point-of-care assay, the Ultegra Rapid Platelet Function Assay-ASA (RPFA-ASA) (Accumetrics Inc., San Diego, California). Citrate-anticoagulated blood 2 ml was added to RPFA-ASA cartridges, which contain fibrinogen-coated beads and platelet agonists. If aspirin has produced the expected antiplatelet effect, fibrinogen-coated beads will not agglutinate, and light transmission will not increase. The result is expressed as aspirin reaction unit (ARU). An ARU 550 indicates the absence of aspirin-induced platelet dysfunction, based on correlation with epinephrine-induced light transmission aggregometry in aspirin-naive patient tested prior to and between 2 to 30 h after aspirin (325 mg) ingestion (15), and is defined as aspirin-resistant. From this study, both the sensitivity (92%) and the specificity (85%) of this assay were determined. The coefficient of variance was 2.5% on repeated measures within patients. The between-patient coefficient of variance was 12.5% for baseline samples and 15.0% for post-aspirin samples. Digital angiograms were analyzed off-line using a computer-based edge-detection program (CMS-GFT, MEDIS, Leiden, The Netherlands) by experienced cardiologists who were unaware of the patient characteristics and outcomes.
Statistical analysis.
Comparisons between the two groups were performed by the Mann-Whitney U test for continuous variables and by the Fisher exact test for dichotomous variables. A logistic regression analysis using forward technique was employed to determine significant independent predictors of CK-MB elevation. A significant level was defined when p < 0.05. All analyses were performed using SPSS 10.0 (SPSS Inc., Chicago, Illinois).
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Results
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The clinical, angiographic, and procedural characteristics of the patients are listed in Tables 1 and 2. A total of 29 (19.2%) out of 151 enrolled patients were found to be aspirin-resistant. The characteristics were matched in the two groups except for the higher incidence of female patients (44.8% vs 19.7%; p = 0.007) in the aspirin-resistant group. All patients underwent successful PCI with <50% diameter stenosis at the target lesion(s) and Thrombolysis In Myocardial Infarction flow grade 3 after the intervention. There was no bailout use of glycoprotein IIb/IIIa inhibitors in any of the patients; no clinical bleeding events occurred. The ratios of hemoglobin pre- and post-PCI in the aspirin-sensitive and -resistant groups were identical at 0.96. None of the patients developed contrast nephropathy. Post-PCI myonecrosis occurred more frequently in the aspirin-resistant patients than in the aspirin-sensitive patients. The incidence of any CK-MB elevation was 51.7% versus 24.6% in the aspirin-resistant and -sensitive groups, respectively (p = 0.006) (Fig. 1). Elevation of TnI occurred in 65.5% of aspirin-resistant patients and 38.5% of aspirin-sensitive patients (p = 0.012) (Fig. 1). The median peak values of CK-MB and TnI in the aspirin-resistant and -sensitive groups, respectively, were 20 and 17 U/l and 6.3 and 0.85 ng/ml. The continuous relationship between ARU and CK-MB, TnI, or bleeding index was not observed. No in-hospital mortality or urgent target vessel revascularization occurred among any of the patients. Variables associated with CK-MB elevation by univariate analysis were aspirin resistance (p = 0.006), bifurcation lesion (p = 0.035), B2/C lesion (p = 0.029), and number of stents used (p = 0.04). Multivariate analysis revealed aspirin resistance (odds ratio [OR] 2.9; 95% confidence interval [CI] 1.2 to 6.9; p = 0.015) and bifurcation lesion (OR 2.8; 95% CI 1.3 to 6.0; p = 0.007) to be independent predictors of CK-MB elevation after PCI.

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Figure 1 Incidence and magnitude of creatine kinase-myocardial band (CK-MB) and troponin I (TnI) elevation in aspirin-resistant (solid bars) and aspirin-sensitive (open bars) patients after percutaneous coronary intervention.
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Discussion
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This is the first study to demonstrate that, despite adequate pretreatment with clopidogrel, patients undergoing non-urgent PCI are at increased risk of myonecrosis when they are determined to be aspirin-resistant using a point-of-care assay, compared with those who are aspirin-sensitive. Elevation of CK-MB has been shown to be associated with a higher incidence of death, myocardial infarction, and repeat revascularization after PCI (16). Prevention of post-PCI myonecrosis, therefore, is of clinical importance. Aspirin has been shown to reduce acute thrombotic complications of balloon angioplasty (1719). Thienopyridine pretreatment (27) and the addition of intravenous glycoprotein IIb/IIIa inhibitors (2023) further improve the outcomes of patients undergoing elective or urgent PCI. However, the role of aspirin in PCI has not been defined in the contemporary era using double or triple antiplatelet therapy.
Aspirin resistance describes the clinical observation of the inability of aspirin to prevent thrombotic complications or the laboratory phenomenon of absence of the effect of aspirin on platelet inhibition tests. Four prior studies demonstrated the association of adverse clinical events in patients with aspirin resistance as determined by different assays (8,1214). Our study extends these observations and provides further evidence on the clinical significance of aspirin resistance. We collected the data prospectively in stable patients undergoing PCI while interventionalists and laboratory personnel performing assays for myonecrosis were blinded to platelet inhibition results. The relatively high percentages of CK-MB and TnI elevations in our population may be due to the high rates of diabetes ( 40%) and complex lesions ( 75% B2/C lesions), and diffuse atherosclerosis as reflected by small reference diameters of 2.6 mm. Despite receiving the maximal antiplatelet effect of clopidogrel with a 300-mg loading dose given >12 h before non-urgent PCI, aspirin-resistant patients had a 2.9-fold increased risk of CK-MB elevation compared with aspirin-sensitive patients.
Our study has several potential limitations. First, the study population was small and Asian in origin. Important trends may not be detected because of a lack of statistical significance and it is not known whether ethnicity plays a role in the differences in aspirin resistance. Second, our study did not have a prospective randomized design, and there might be unrecognized confounders that may influence the occurrence of myonecrosis in addition to aspirin responsiveness. Third, the antiplatelet effect of aspirin may fluctuate in patients at the same dosage. A single baseline measurement may not reflect the extent of platelet inhibition over long periods of time. However, during PCI when maximal antithrombotic action is desirable, a point-of-care platelet inhibition assay may give instant information on the efficacy of aspirin, regardless of previous antiplatelet effect.
Finally, we conclude that aspirin resistance is associated with a 2.9-fold increased incidence of myonecrosis as evidenced by CK-MB elevation following non-urgent PCI with adequate clopidogrel pretreatment. Our results may have implications for the need of identification of aspirin resistance in patients undergoing PCI and the use of alternative or additional antithrombotic therapy to minimize procedural complications.
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F. Alfonso and D. J. Angiolillo
Platelet Function Assessment to Predict Outcomes After Coronary Interventions: Hype or Hope?
J. Am. Coll. Cardiol.,
November 7, 2006;
48(9):
1751 - 1754.
[Full Text]
[PDF]
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D. L. Bhatt
Shifting the Diagnosis of Periprocedural Myocardial Infarction Upstream
Circulation,
October 31, 2006;
114(18):
1898 - 1900.
[Full Text]
[PDF]
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A. D. Michelson, A. L. Frelinger, and M. I. Furman
Resistance to antiplatelet drugs
Eur. Heart J. Suppl.,
October 1, 2006;
8(suppl_G):
G53 - G58.
[Abstract]
[Full Text]
[PDF]
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D. J. Angiolillo, E. Bernardo, C. Ramirez, M. A. Costa, M. Sabate, P. Jimenez-Quevedo, R. Hernandez, R. Moreno, J. Escaned, F. Alfonso, et al.
Insulin Therapy Is Associated With Platelet Dysfunction in Patients With Type 2 Diabetes Mellitus on Dual Oral Antiplatelet Treatment
J. Am. Coll. Cardiol.,
July 18, 2006;
48(2):
298 - 304.
[Abstract]
[Full Text]
[PDF]
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T. Wang and D. L. Bhatt
Aspirin and clopidogrel resistance: an emerging clinical entity: reply
Eur. Heart J.,
July 2, 2006;
27(14):
1754 - 1755.
[Full Text]
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U. S. Tantry, K. P. Bliden, and P. A. Gurbel
Reply
J. Am. Coll. Cardiol.,
June 20, 2006;
47(12):
2566 - 2566.
[Full Text]
[PDF]
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R. S. Hillman
Platelet Aspirin Resistance Detection and Validation
J. Am. Coll. Cardiol.,
June 20, 2006;
47(12):
2565 - 2565.
[Full Text]
[PDF]
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L. H Cavallari, C. M Helgason, L. D Brace, M. A. Viana, and E. A Nutescu
Sex Difference in the Antiplatelet Effect of Aspirin in Patients with Stroke
Ann. Pharmacother.,
May 1, 2006;
40(5):
812 - 817.
[Abstract]
[Full Text]
[PDF]
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E. D. Michos, R. Ardehali, R. S. Blumenthal, R. A. Lange, and H. Ardehali
Aspirin and Clopidogrel Resistance
Mayo Clin. Proc.,
April 1, 2006;
81(4):
518 - 526.
[Abstract]
[Full Text]
[PDF]
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T. H. Wang, D. L. Bhatt, and E. J. Topol
Aspirin and clopidogrel resistance: an emerging clinical entity
Eur. Heart J.,
March 2, 2006;
27(6):
647 - 654.
[Abstract]
[Full Text]
[PDF]
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E. I. Lev, R. T. Patel, K. J. Maresh, S. Guthikonda, J. Granada, T. DeLao, P. F. Bray, and N. S. Kleiman
Aspirin and Clopidogrel Drug Response in Patients Undergoing Percutaneous Coronary Intervention: The Role of Dual Drug Resistance
J. Am. Coll. Cardiol.,
January 3, 2006;
47(1):
27 - 33.
[Abstract]
[Full Text]
[PDF]
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E. I. Lev, R. T. Patel, K. J. Maresh, S. Guthikonda, J. Granada, T. DeLao, P. F. Bray, and N. S. Kleiman
Aspirin and Clopidogrel Drug Response in Patients Undergoing Percutaneous Coronary Intervention: The Role of Dual Drug Resistance
J. Am. Coll. Cardiol.,
December 13, 2005;
(2005)
j.jacc.2005.08.058v1.
[Abstract]
[Full Text]
[PDF]
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J. Herrmann
Peri-procedural myocardial injury: 2005 update
Eur. Heart J.,
December 1, 2005;
26(23):
2493 - 2519.
[Abstract]
[Full Text]
[PDF]
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U. S. Tantry, K. P. Bliden, and P. A. Gurbel
Overestimation of Platelet Aspirin Resistance Detection by Thrombelastograph Platelet Mapping and Validation by Conventional Aggregometry Using Arachidonic Acid Stimulation
J. Am. Coll. Cardiol.,
November 1, 2005;
46(9):
1705 - 1709.
[Abstract]
[Full Text]
[PDF]
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P. J. Mason, A. K. Jacobs, and J. E. Freedman
Aspirin Resistance and Atherothrombotic Disease
J. Am. Coll. Cardiol.,
September 20, 2005;
46(6):
986 - 993.
[Abstract]
[Full Text]
[PDF]
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D. L. Bhatt and E. J. Topol
Periprocedural Cardiac Enzyme Elevation Predicts Adverse Outcomes
Circulation,
August 9, 2005;
112(6):
906 - 922.
[Full Text]
[PDF]
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N. Ajzenberg, P. Aubry, M.-G. Huisse, A. Cachier, W. El Amara, L. J. Feldman, D. Himbert, D. Baruch, M.-C. Guillin, and Ph. G. Steg
Enhanced Shear-Induced Platelet Aggregation in Patients Who Experience Subacute Stent Thrombosis: A Case-Control Study
J. Am. Coll. Cardiol.,
June 7, 2005;
45(11):
1753 - 1756.
[Abstract]
[Full Text]
[PDF]
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S. R. Steinhubl, R. Charnigo, and D. J. Moliterno
Resistance to Antiplatelet Resistance: Is it Justified?
J. Am. Coll. Cardiol.,
June 7, 2005;
45(11):
1757 - 1758.
[Full Text]
[PDF]
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E. R. Bates, W. C. Lau, and B. E. Bleske
Loading, Pretreatment, and Interindividual Variability Issues With Clopidogrel Dosing
Circulation,
May 24, 2005;
111(20):
2557 - 2559.
[Full Text]
[PDF]
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E. R. Bates and W. C. Lau
Controversies in Antiplatelet Therapy for Patients With Cardiovascular Disease
Circulation,
May 3, 2005;
111(17):
e267 - e271.
[Full Text]
[PDF]
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P. Harrison, H. Segal, K. Blasbery, C. Furtado, L. Silver, and P. M. Rothwell
Screening for Aspirin Responsiveness After Transient Ischemic Attack and Stroke: Comparison of 2 Point-of-Care Platelet Function Tests With Optical Aggregometry
Stroke,
May 1, 2005;
36(5):
1001 - 1005.
[Abstract]
[Full Text]
[PDF]
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W. W. O'Neill, S. R. Dixon, and C. L. Grines
The year in interventional cardiology
J. Am. Coll. Cardiol.,
April 5, 2005;
45(7):
1117 - 1134.
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W.-H. Chen, P.-Y. Lee, W. Ng, H.-F. Tse, and C.-P. Lau
Is aspirin resistance or female gender associated with a high incidence of myonecrosis after nonurgent percutaneous coronary intervention? Reply
J. Am. Coll. Cardiol.,
February 15, 2005;
45(4):
636 - 636.
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[PDF]
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T. S. Poulsen, A. Kastrup, and H. Mickley
Is aspirin resistance or female gender associated with a high incidence of myonecrosis after nonurgent percutaneous coronary intervention?
J. Am. Coll. Cardiol.,
February 15, 2005;
45(4):
635 - 636.
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[PDF]
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A. N. DeMaria, O. Ben-Yehuda, D. Berman, G. K. Feld, B. H. Greenberg, J. D. Knoke, K. U. Knowlton, W. Y.W. Lew, J. Narula, D. Sahn, et al.
Highlights of the year in JACC 2004
J. Am. Coll. Cardiol.,
January 4, 2005;
45(1):
137 - 153.
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A. D. Michelson
Platelet Function Testing in Cardiovascular Diseases
Circulation,
November 9, 2004;
110(19):
e489 - e493.
[Full Text]
[PDF]
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M. Cattaneo
Aspirin and Clopidogrel: Efficacy, Safety, and the Issue of Drug Resistance
Arterioscler Thromb Vasc Biol,
November 1, 2004;
24(11):
1980 - 1987.
[Abstract]
[Full Text]
[PDF]
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S. P. Schulman
Antiplatelet Therapy in Non-ST-Segment Elevation Acute Coronary Syndromes
JAMA,
October 20, 2004;
292(15):
1875 - 1882.
[Abstract]
[Full Text]
[PDF]
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J.P. Collet, G. Montalescot, B. Blanchet, M.L. Tanguy, J.L. Golmard, R. Choussat, F. Beygui, L. Payot, N. Vignolles, J.P. Metzger, et al.
Impact of Prior Use or Recent Withdrawal of Oral Antiplatelet Agents on Acute Coronary Syndromes
Circulation,
October 19, 2004;
110(16):
2361 - 2367.
[Abstract]
[Full Text]
[PDF]
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R. I. Levin
Theriac found? Nitric oxide-aspirin and the search for the universal cure
J. Am. Coll. Cardiol.,
August 4, 2004;
44(3):
642 - 643.
[Full Text]
[PDF]
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Aspirin Resistance Predicts Myonecrosis During PCI
Journal Watch Cardiology,
May 7, 2004;
2004(507):
5 - 5.
[Full Text]
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