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A history of late and very late stent thrombosis is not associated with increased activation of the contact system, a case control study

Thrombosis Journal volume 8, Article number: 6 (2010) Cite this article

Abstract

Background

The pathophysiological pathways resulting in Late Stent Thrombosis (LST) remain uncertain. Findings from animal studies indicate a role of the intrinsic coagulation pathway in arterial thrombus formation, while clinical studies support an association with ischemic cardiovascular disease. It is currently unknown whether differences in the state of the contact system might contribute to the risk of LST or Very Late Stent Thrombosis (VLST). We assessed the relation between levels of several components involved in the contact system and a history of LST and VLST, termed (V)LST in a cohort of 20 patients as compared to a matched control group treated with PCI.

Methods and Results

Activated factor XII (FXIIa), FXII zymogen (FXII), FXIIa-C1-esterase inhibitor (C1-inhibitor), Kallikrein-C1-inhibitor, FXIa-C1-inhibitor and FXIa-α1-antitrypsin (AT-inhibitor) complexes were measured by Enzyme-linked immunosorbent assy (ELISA) methodology.

Cases and controls showed similar distributions in sex, age, baseline medications and stent type. Patients with a history of (V)LST had a significantly greater stent burden and a higher number of previous myocardial infarctions than the control patients.

There were no significant between-group differences in the plasma levels of the components of the contact system.

Conclusion

In a cohort of patients with a history of (V)LST, we did not observe differences in the activation state of the intrinsic coagulation system as compared to patients with a history of percutaneous coronary intervention without stent thrombosis.

Introduction

Coronary stents are routinely employed in percutaneous coronary revascularization procedures and have significantly decreased the rates of acute vessel closure and restenosis[1]. The rate of stent thrombosis (ST) after percutaneous coronary intervention (PCI) is estimated to be as low as <1% of the cases following implantation of bare-metal stents (BMS), of which approximately 50% occur within the first month following implantation [2, 3]. However, the potential fatality due to acute vessel closure, still makes ST one of the most frightening complications after percutaneous coronary intervention (PCI) [4, 5]. During the last years, concerns have been raised regarding later occurrence of ST in drug-eluting stents (DES), in particular beyond the traditional 1-month timeframe[6–8]. The actual incremental risk associated with DES has been an issue of controversy.

Among others, discontinuation of antiplatelet therapy, increased intrinsic platelet activity, incomplete stent apposition, bifurcation stenting, renal insufficiency and diabetes have been discussed as possible risk factors for the development of late stent thrombosis (LST) (1-12 months) and very late stent thrombosis (VLST) (>12 months), and local inflammatory processes have been shown to be associated with (V)LST in autopsy materials [9–12]. However, the occurrence of (V)LST most likely has a multifactorial origin and the exact pathophysiological scenario leading to (V)LST remains uncertain.

Currently there is no established method to identify patients at high risk of (V)LST.

Contact activation, believed to be potentiated by negatively charged surfaces, results in the activation of the zymogen FXII to FXIIa and affects several pathophysiological processes including hypotension, inflammation, thrombosis and fibrinolysis[13–20].

Several components of the contact system have been found to be related to coronary heart disease (CHD) [21–27] and recent findings from animal studies indicate that FXII might even be essential for arterial thrombus formation[28].

However, in contrast, other clinical studies have demonstrated low FXII levels as a risk factor for coronary heart disease or showed a U-shaped association to risk[29–31]. Clinical settings and patient populations differ substantially between the existing clinical studies, and even if an association of the contact system to CHD and thrombosis seems likely, the exact mechanisms remain poorly understood. Whether the activation state of the contact system might be associated with the occurrence of (V)LST has never been addressed.

The objective of the present study was to test the hypothesis that patients having survived an event of (V)LST have a generally different activation state of the contact system as compared to matched patients without a history of this condition.

Methods

Study design and patient population

The study was a single-centre cohort study (Risk markers for Late in Stent Thrombosis (RIST)), in which 20 patients with a history of definitive (V)LST (as proposed by the Academic Research Consortium [32]) were compared to 32 PCI controls without (V)LST. These individuals were matched with respect to age, sex, current antiplatelet medication and stent type [Seventy-five percent of the (V)LST patients and 84.4% of the controls treated with DES (TAXUS EXPRESS). The remaining patients received BMS (Flexmaster or Express stents)]. Patients were included at the Stavanger University Hospital, Norway in March 2008.

All patients who could be identified from a local PCI registry with a history of a definite (V)LST admitted during the last 4 years were included in the study. Exclusion criteria were age below 18 years or unwillingness or inability to provide informed consent.

Assessment of previous clinical history, current and previous medication and risk factors were based on hospital records, angiographic records and personal interview. Additionally, hospital journals were searched for confirmation of reported data. Diabetes mellitus was defined as either whole blood fasting glucose concentrations above 6.1 mmol/L, two hour post glucose load concentrations above 10.0 mmol/L or medically treated diabetes mellitus, and hypercholesterolemia was defined as total cholesterol concentrations above 6.5 mmol/L or medically treated hypercholesterolemia. Arterial hypertension was defined as repeated blood pressure measurements above 140/90 mmHg or treated hypertension.

Written informed consent was obtained from all patients. The study was approved by the Regional Board of Research Ethics and the Norwegian Health authorities and conducted in accordance with the Helsinki declaration of 1971, as revised in 1983.

Blood Sampling Procedures and Laboratory Measurements

Blood samples were drawn by puncture of an antecubital vein with minimal stasis and centrifuged twice for 15 minutes at 2.000 × g and for 10 minutes at 11.000 × g at 18°C. Laboratory measurements were either performed immediately following centrifugation or following storage of the samples at -80°C.

A measure of FXIIa in citrated plasma was obtained by enzyme linked immunosorbent assay (ELISA methodology), using a specific monoclonal capture antibody (Mab 2/215) with no detectable recognition of FXII or FXIIa-C1 inhibitor complexes [33]. The alkaline phosphatase conjugated secondary antibody was a sheep polyclonal antibody against FXIIa. Kits were supplied by Axis-Shield, Dundee, United Kingdom.

FXII was measured in citrated plasma using ELISA, based on a sheep polyclonal anti-FXII capture antibody and a horseradish peroxidase conjugated goat polyclonal anti-FXII secondary antibody (Enzyme Research Laboratories).

Complexes of FXIa, FXIIa, Kallikrein and C1-inhibitor and complexes of FXIa and AT-inhibitor were measured in EDTA plasma, to which soybean trypsin and benzamidin (Sigma-Aldrich) was added to prevent contact activation during collection and processing, with enzyme-linked immunosorbent assays (ELISAs), as previously described with minor modifications[27]. The detection limits were 0.095% for all four assays, respectively.

Hs-CRP was quantified in serum by a Tina quant® C-reactive protein (latex) high sensitivity assay (Roche Diagnostics) [34].

Statistical methods

Approximately normally distributed variables were given as mean and standard deviation, whilst skewed distributions were given as median and interquartile range. For measurements of inhibitor complexes, values below the cut-off limit of 0.095% were set to 0.095. The two sample t-test was used to examine differences between the patient and control group for normally distributed variables, whilst the Mann-Whitney-U test was applied to test for the equality of the median of two samples of variables with a skewed distribution. The Chi-square test for association was applied for baseline categorical variables. The statistical analyses were performed using SPSS version 15.0. In all tests a two-tailed P-value of < 0.05 was considered to statistically significant.

Results

21 patients with a history of (V)LST were identified from our PCI registry. One patient was not included in the study due to unwillingness to participate. The total study population consisted of 52 patients. Twenty patients suffered from a definite late or very late stent thrombosis within the last 43 (median 10) months and there were 32 PCI controls without (V)LST (median follow-up time 15 months). Clopidogrel had been discontinued in all patients prior to the development of (V)LST and after the recommended treatment time of 6 - 12 months, with a median discontinuation period of 202 days, whereas all were receiving acetylsalicylic acid (ASA). Ninety percent of the (V)LST patients were back on dual antiplatelet therapy consisting of ASA and clopidogrel when they were tested, and 91% of controls had been on continuous dual antiplatelet treatment. The remaining 10 and 9%, were only treated with ASA at the time of testing.

Baseline variables and demographics for the two groups are displayed in Table 1 and baseline biochemical variables are displayed in Table 2. There was no significant difference in the incidence of multivessel disease (50% vs 40.6%; p = 0.57) or minimum stent diameter 2.8 ± 0.4 mm vs 2.9 ± 0.4 mm (Mean ± SD; p = 0.28) between the (V)LST and the PCI control group. The total stent burden was significantly greater in the (V)LST group as compared to the PCI control group (total stent length 36.0 (30.5-48.0 mm) vs 20.0 (16.5-28.0 mm) (Median (25-75% percentiles; p < 0.01). Specific variables related to (V)LST are displayed in Table 3.

Table 1 Baseline clinical characteristics for patients with a history of late or very late stent thrombosis (LST/VLST) and controls.
Full size table
Table 2 Baseline biochemical characteristics for patients with a history of late or very late stent thrombosis (LST/VLST) and controls.
Full size table
Table 3 Characteristics of patients with (V)LST.
Full size table

However, for none of the investigated components of the contact system, significant differences could be observed between the groups (Table 2).

Discussion

In the present study we could not demonstrate differences in the activation state of the contact system after measuring several different components of the intrinsic coagulation and the plasma kallikrein-kinin system (PKKS) in patients with a history of (V)LST as compared to controls.

Stent thrombosis is currently considered a multifactorial problem related to patient, lesion, procedure, factors related to blood coagulation and response to antiplatelet therapy[3]. For understandable reasons much attention has been on the contribution of platelets and the (lack of) efficacy of platelet inhibiting agents. Stent thrombosis, in particular following the implantation of DES, has been mainly attributed to discontinuation or premature cessation of clopidogrel[5, 35]. However, dual antiplatelet therapy has not been found to entirely prevent the occurrence of LST[36]. In addition, the occurrence of ST does not seem to be strictly related to the time point of clopidogrel cessation, as the event often occurs a long time after its cessation. Moreover, the majority of patients do not develop ST despite premature cessation of antiplatelet medication. Consequently, it seems obvious that other factors besides discontinuation of antiplatelet therapy may be involved in the pathogenesis of ST.

Renne et al. provided a challenging new concept for FXII in arterial thrombosis, showing impaired thrombus stability in FXII deficient mice[28]. In addition they showed that FXII deficient mice were partly protected against ischemic stroke. Moreover, numerous clinical studies have reported a role of different components of the contact system and the PKKS in CHD, but detailed pathophysiological mechanisms still remain poorly understood. Increased FXII zymogen levels have primarily been associated with a decrease in risk for MI and outcome [29, 31]. In contrast, elevated plasma FXIIa has been shown to be associated with an increased risk of CHD, the extent of coronary atheroma and with survival status following an MI compared to healthy controls[21–24]. Moreover, FXIIa measured after an MI independently predicted recurrent coronary occlusive events, [25] and FXIIa in chest pain patients at hospital admission predicted long-term mortality [26] whereas other studies failed to show clear associations of FXIIa to CHD[30]. Measurement of inhibited FXIIa (as the FXIIa-C1-inhibitor complex) suggested that the level of this inhibitor complex was associated with cardiovascular risk [27].

To our knowledge, late- and very late stent thrombosis have not been described in relation to the contact and/or plasma kallikrein-kinin system yet. In our analyses, we examined different components of these systems and their possible association to (V)LST. Low levels of inhibitor complexes for the PKKS in both groups reflect a high general risk for CHD [27]. However, for none of the measured biochemical variables, significant differences between patients with a history of (V)LST and controls were noted. Consequently, our results do not suggest a role of the contact system in the pathogenesis of (V)LST.

The design of our study carries along several issues that have to be considered with caution. Our ST population consisted of patients suffering from both late- and very late stent thrombosis, as well as of patients with implantation of both DES and BMS. The pathophysiology of ST may differ between these settings and may also lead to a different involvement of the contact system.

The main limitation of the study is its retrospective design, with no knowledge of the state of the contact system at the time of the event. Ideally, also the discontinuation period for antiplatelet medication should have been matched between the case and control group. However, as most patients with a history of LST receive double antiplatelet medication for an indefinite time period in contrast to cessation of clopidogrel nine months to two years following uncomplicated stent implantation, an optimal matching regarding this parameter could not be achieved.

In addition, the results of the present study are limited by the restricted sample size. To achieve a statistical power of 80% at a significance level of 5%, large differences in variables between the groups would have been necessary, for example 7% for FXII, 31% for FXIIa, and 53% for FXIIa-Kallikrein-inhibitor. Whether potentially smaller changes may be of biological importance is not known and cannot be excluded by our data.

Conclusion

The present study does not suggest an association of the activation state of the intrinsic coagulation system in relation to the occurrence of (V)LST.

Funding

This work was supported by a grant of the Stavanger University Hospital Research Foundation.

Conflicts of interests

Co-author David Pritchard is employee at AXIS-Shield, UK.

References

  1. Jaffe R, Strauss BH: Late and very late thrombosis of drug-eluting stents. Evolving concepts and perspectives. J Am Coll Cardiol 2007, 50: 119-27. 10.1016/j.jacc.2007.04.031

    Article  CAS  PubMed  Google Scholar 

  2. Bavry AA, Kumbhani DJ, Helton Tj, Bhatt DL: Risk of thrombosis with the use of sirolimus eluting stents for precutaneous coronaryintervention. Am J Cardiol 2005, 95: 1469-72. 10.1016/j.amjcard.2005.02.015

    Article  CAS  PubMed  Google Scholar 

  3. Windecker S, Meier B: Late stent thrombosis. Circulation 2007, 116: 1952-65. 10.1161/CIRCULATIONAHA.106.683995

    Article  PubMed  Google Scholar 

  4. Wenaweser P, Rey C, Eberli FR, Togni M, Tuller D, Locher S, et al.: Stent thrombosis following bare-metal stent implantation: sucess of emergency percutaneous coronary intervention and predictors of adverse outcome. Eur Heart J 2005, 26: 1180-1187. 10.1093/eurheartj/ehi135

    Article  PubMed  Google Scholar 

  5. Kuchulakanti PK, Chu WW, Torguson R, Ohlman P, Rha SW, Clavijo LC, et al.: Correlates and long-term outcomes of angiographically proven stent thrombosis with sirolimus- and paclitaxel-eluting stents. Circulation 2006, 113: 1108-1113. 10.1161/CIRCULATIONAHA.105.600155

    Article  CAS  PubMed  Google Scholar 

  6. Spaulding C, Daemen J, Boersma E, Cutlip DE, Serruys PW: A pooled analysis of data comparing sirolimus-eluting stents with bare-metalstents. N Eng J Med 2007, 356: 989-997. 10.1056/NEJMoa066633

    Article  CAS  Google Scholar 

  7. Stone GW, Moses JW, Ellis SG, Schofer J, Dawkins KD, Morice MC, et al.: Safety and efficiacy of sirolimus and paclitaxel-elutingcoronary stents. N Eng J Med 2007, 356: 998-1008. 10.1056/NEJMoa067193

    Article  CAS  Google Scholar 

  8. Kastrati A, Mehili J, Pache J, Kaiser C, Valgimigli M, Kelbaeck H, et al.: Analysis of 14 trials comparing sirolimus-eluting stents with bare-metal stents. N Eng J Med 2007, 356: 1030-39. 10.1056/NEJMoa067484

    Article  CAS  Google Scholar 

  9. Cook S, Wenaweser P, Togni M, Billinger M, Morger C, Seiler C, et al.: Incomplete stent apposition and very late stent thrombosis after drug-eluting stent implantation. Circulation 2007, 115: 2426-24. 10.1161/CIRCULATIONAHA.106.658237

    Article  CAS  PubMed  Google Scholar 

  10. Virmany R, Guaglliumi G, Farb A, Musumeci G, Grieco N, Motta T, et al.: Localized hypersensitivity and late coronary thrombosis secondary to a sirolimus-eluting stent: should we be cautious? Circulation 2004, 109: 701-705. 10.1161/01.CIR.0000116202.41966.D4

    Article  Google Scholar 

  11. Ajzenberg N, Aubry P, Huisse MG, Cachier A, El Amara W, Feldman LJ, et al.: Enhanced shear-induced platelet aggregation in patients who experience subacute stent thrombosis. J Am Coll Cardiol 2005, 45: 1753-56. 10.1016/j.jacc.2004.10.079

    Article  PubMed  Google Scholar 

  12. Joner M, Finn AV, Farb A, Mont EK, Kolodgie FD, Ladich E, et al.: Pathology of drug-eluting stents in humans: delayed healing and late thrombotic risk. J Am Coll Cardiol 2006, 48: 193-202. 10.1016/j.jacc.2006.03.042

    Article  PubMed  Google Scholar 

  13. Kaplan AP, Austen KF: A prealbumin activator of prekallikrein. II. Derivation of activators of prekallikrein from active Hageman factor by digestion with plasmin. J Exp Med 1971, 133: 696-712. 10.1084/jem.133.4.696

    Article  PubMed Central  CAS  PubMed  Google Scholar 

  14. Murano G: The "Hageman" Connection: Interrelationships of blood coagulation, fibrino(geno)lysis, kinin generation, and complement activation. Am J Hematol 1978, 4: 409-17. 10.1002/ajh.2830040412

    Article  CAS  PubMed  Google Scholar 

  15. Kurachi K, Fujikawa K, Davie EW: Mechanism of activation of bovine factor XI by factor XII and factor XIIa. Biochemistry 1980, 19: 1330-8. 10.1021/bi00548a011

    Article  CAS  PubMed  Google Scholar 

  16. Radcliffe R, Bangdasarian A, Colman R, Nemerson Y: Activation of bovine factor VII by hageman factor fragments. Blood 1977, 50: 611-7.

    CAS  PubMed  Google Scholar 

  17. Ghebrehiwet B, Randazzo BP, Dunn JT, Silverberg M, Kaplan AP: Mechanisms of activation of the classical pathway of complement by Hageman factor fragment. J Clin Invest 1983, 71: 1450-6. 10.1172/JCI110898

    Article  PubMed Central  CAS  PubMed  Google Scholar 

  18. Toosi Z, Sedor JR, Mettler MA, Everson B, Young T, Ratnoff OD: Induction of expression of monocyte interleukin 1 by Hageman factor (factorXII). Proc Natl Acad Sci USA 1992, 89: 11969-72. 10.1073/pnas.89.24.11969

    Article  Google Scholar 

  19. Wachtfogel YT, Pixley RA, Kucich U, Abrams W, Weinbaum G, Schapira M, et al.: Purified plasma factor XIIa aggregates human neutrophils and causes degranulation. Blood 1986, 67: 1731-7.

    CAS  PubMed  Google Scholar 

  20. Wachtfogel YT, Kettner C, Hack CE, Nuijens JH, Reilly TM, Knabb RM, et al.: Thrombin and human plasma kallikrein inhibition during simulated extracorporeal circulation block platelet and neutrophil activation. Thromb Haemost 1998, 80: 686-91.

    CAS  PubMed  Google Scholar 

  21. Miller GJ, Esnouf MP, Burgess AI, Cooper JA, Mitchell JP: Risk of coronary heart disease and activation of factor XII in middle-agedmen. Arterioscler Thromb Vasc Biol 1997, 17: 2103-6.

    Article  CAS  PubMed  Google Scholar 

  22. Zito F, Drummond F, Bujac SR, Esnouf MP, Morrissey JH, Humphries SE, et al.: Epidemiological and genetic associations of activated factor XII concentration with factor VII activity, fibrinopeptide A concentration, and risk of coronary heart disease in men. Circulation 2000, 102: 2058-62.

    Article  CAS  PubMed  Google Scholar 

  23. Cooper JA, Miller GJ, Bauer KA, Morrissey JH, Meade TW, Howarth DJ, et al.: Comparison of novel hemostatic factors and conventional risk factors for prediction of coronary heart disease. Circulation 2000, 102: 2816-22.

    Article  CAS  PubMed  Google Scholar 

  24. Kohler HP, Carter AM, Stickland MH, Grant PJ: Levels of activated FXII in survivors of myocardial infarction: association with circulating risk factors and extent of coronary artery disease. Thromb Haemost 1998, 79: 14-8.

    CAS  PubMed  Google Scholar 

  25. Grundt H, Nilsen DW, Hetland O, Valente E, Fagertun HE: Activated factor 12 (FXIIa) predicts recurrent coronary events after an acute myocardial infarction. Am Heart J 2004, 147: 260-6. 10.1016/j.ahj.2003.07.012

    Article  CAS  PubMed  Google Scholar 

  26. Pönitz V, Brügger-Andersen T, Pritchard D, Grundt H, Staines H, Nilsen DW, RACS Study Group: Activated factor XII type A predicts long-term mortality in patients admitted with chest pain. J Thromb Haemost 2009, 7(2):277-87. 10.1111/j.1538-7836.2008.03248.x

    Article  PubMed  Google Scholar 

  27. Govers-Riemslag JW, Smid M, Cooper JA, Bauer KA, Rosenberg RD, Hack CE, et al.: The plasma kallikrein.kinin system and risk of cardiovascular disease in men. J Thromb Haemost 2007, 5: 1896-1903. 10.1111/j.1538-7836.2007.02687.x

    Article  CAS  PubMed  Google Scholar 

  28. Renné T, Pozgajová M, Grüner S, Schuh K, Pauer HU, Burfeind P, et al.: Defective thrombus formation in mice lacking coagulation factor XII. J Exp Med 2005, 202: 271-81. 10.1084/jem.20050664

    Article  PubMed Central  PubMed  Google Scholar 

  29. Doggen CJ, Rosendaal FR, Meijers JC: Levels of intrinsic coagulation factors and risk of myocardial infarction among men: opposite and synergistic effects of factors XI and XII. Blood 2006, 108: 4045-51. 10.1182/blood-2005-12-023697

    Article  CAS  PubMed  Google Scholar 

  30. Bach J, Endler G, Winkelmann BO, Boehm W, Maerz C, Mannhalter P, et al.: Coagulation factor XII (FXII) activity, activated FXII, distribution of FXII C 46T gene polymorphism and coronary risk. J Thromb Haemost 2008, 6: 291-6.

    Article  CAS  PubMed  Google Scholar 

  31. Endler G, Marsik C, Jilma B, Schickbauer T, Quehenberger P, Mannhalter C: Evidence of a U-shaped association between Factor XII activity and overall survival. J Thromb Haemost 2007, 5: 1143-8. 10.1111/j.1538-7836.2007.02530.x

    Article  CAS  PubMed  Google Scholar 

  32. Cutlip DE, Windecker S, Mehran R, Boam A, Cohen DJ, van Es GA, et al.: Clinical end points in coronary stent trials. Circulation 2007, 115: 2344-2351. 10.1161/CIRCULATIONAHA.106.685313

    Article  PubMed  Google Scholar 

  33. Esnouf MP, Burgess AI, Dodds AW, Sarphie AF, Miller GJ: A monoclonal antibody raised against human beta-factor XIIa which also recognizes alpha-factor XIIa but not Factor XII or complexes of Factor XIIa with C1 esterase inhibitor. Thromb Haemost 2000, 83: 874-81.

    CAS  PubMed  Google Scholar 

  34. Roberts WL, Moulton L, Law TC, Farrow G, Cooper-Anderson M, Savory J, et al.: Evaluation of nine high-sensitivity C-reactive protein methods. Clin Chem 2001, 47: 418-25.

    CAS  PubMed  Google Scholar 

  35. Nilsen DWT, Melberg T, Larsen AI, Barvik S, Bonarjee V: Late complications following the deployment of drug eluting stents. Int J Cardiol 2006, 109(3):398-401. 10.1016/j.ijcard.2005.05.029

    Article  PubMed  Google Scholar 

  36. Daemen J, Wenaweser P, Tsuchida K, Albrecht L, Vaina S, Morger C, et al.: Early and late coronary stent thrombosis of sirolismus-eluting and paclitaxel-eluting stents in routine clinical pactise. Lancet 2007, 369: 667-678. 10.1016/S0140-6736(07)60314-6

    Article  CAS  PubMed  Google Scholar 

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Authors and Affiliations

  1. Institute of Medicine, University of Bergen, Bergen, Norway

    Volker Pönitz, Trygve Brügger-Andersen, Heidi Grundt, Patrycja Næsgaard, Alf I Larsen & Dennis W Nilsen

  2. Department of Medicine, Stavanger University Hospital, Stavanger, Norway

    Volker Pönitz, Trygve Brügger-Andersen, Heidi Grundt, Patrycja Næsgaard, Alf I Larsen & Dennis W Nilsen

  3. Laboratory for Clinical Thrombosis and Haemostasis, Department of Internal Medicine and Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands

    José W Govers-Riemslag, Hugo ten Cate & Rene van Oerle

  4. Axis-Shield, Dundee, UK

    David Pritchard

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  1. Volker Pönitz
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Authors' contributions

VP participated in the design and conduction of the study and data collection, performed the statistical analysis and is main author of the manuscript. JG carried out the ELISAs on inhibitor complexes of the PKKS and helped to draft the manuscript. HtC participated in the design of the study and helped to draft the manuscript. RvO participated in the conduction of the study and data collection. TBA participated in the conduction of the study, data collection and helped to draft the manuscript. HG participated in the design of the study and assisted in the performance of the statistical analyses. PN participated in the conduction of the study and data collection. DP carried out the ELISAs on FXII and FXIIa and helped to draft the manuscript. AIL provided intellectual contributions in the interpretation of the angiographic data and helped to draft the manuscript. DN participated substantially in the design of the study and helped to draft the manuscript. All authors read and approved the final manuscript.

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Pönitz, V., Govers-Riemslag, J.W., ten Cate, H. et al. A history of late and very late stent thrombosis is not associated with increased activation of the contact system, a case control study. Thrombosis J 8, 6 (2010). https://doi.org/10.1186/1477-9560-8-6

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Thrombosis Journal

ISSN: 1477-9560

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