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THE EFFECTS OF THYROID-STIMULATING HORMONE, FREE THYROXINE LEVELS, AND THYROID ANTIBODIES ON MEAN PLATELET VOLUME: ORIGINAL RESEARCH. JOURNAL OF CONTEMPORARY MEDICINE 2022. [DOI: 10.16899/jcm.932053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Cui Y, Heuser K, Bauer N, Neiger R. Coagulation parameters in hyperthyroid cats before and after radioiodine treatment compared with healthy controls. J Feline Med Surg 2019; 21:1134-1140. [PMID: 30571457 PMCID: PMC10814272 DOI: 10.1177/1098612x18820145] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2024]
Abstract
OBJECTIVES The aim of the study was to describe the coagulatory state of hyperthyroid cats before and after successful radioiodine therapy (RIT) compared with healthy age-matched controls, using classical coagulation parameters and thromboelastogram (TEG) as a global assessment method. The differences in coagulation activity after RIT, depending on the thyroid hormone (normal vs low total thyroxine [T4]) state, were also evaluated. METHODS Fifteen hyperthyroid cats and 10 healthy age-matched controls were recruited. Hyperthyroid cats that remained hyperthyroid 14 days after RIT were excluded. Haematology, biochemistry, T4, prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen and TEG were assessed in control cats and hyperthyroid cats before and 7 and 14 days after RIT. Two weeks after successful RIT, further comparisons were made between cats with normal T4 vs those with low T4. RESULTS Fourteen days after successful RIT, 7/15 cats had normal T4 and 8/15 had low T4. Thrombocytosis was noted in 6/15 cats after treatment. Fibrinogen was significantly higher (P <0.001) and PT shorter (P <0.01) in the hyperthyroid cats compared with the healthy controls and these changes persisted after RIT. Persistent increases in fibrinogen, PT, TEG maximal amplitude and TEG clot rigidity, reflecting clot stability, after RIT primarily occurred in the cats with normal T4. TEG-K (time until preset amplitude of 20 mm is reached) and alpha (α) angle reflected impaired fibrin cross-linking ability prior to RIT, which significantly increased after therapy (P <0.05). CONCLUSIONS AND RELEVANCE Based on some of the coagulation parameters, cats with hyperthyroidism showed hypercoagulable tendencies, which were mildly increased after RIT, possibly due to transient radiation-induced thyroiditis.
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Affiliation(s)
- Yi Cui
- Department of Veterinary Clinical Sciences, Small Animal Internal Medicine, Justus-Liebig University, Giessen, Germany
| | - Katharina Heuser
- Department of Veterinary Clinical Sciences, Small Animal Internal Medicine, Justus-Liebig University, Giessen, Germany
| | - Natali Bauer
- Department of Veterinary Clinical Sciences, Small Animal Internal Medicine, Justus-Liebig University, Giessen, Germany
| | - Reto Neiger
- Small Animal Clinic Hofheim, Hofheim, Germany
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Bano A, Chaker L, de Maat MPM, Atiq F, Kavousi M, Franco OH, Mattace-Raso FUS, Leebeek FWG, Peeters RP. Thyroid Function and Cardiovascular Disease: The Mediating Role of Coagulation Factors. J Clin Endocrinol Metab 2019; 104:3203-3212. [PMID: 30938758 DOI: 10.1210/jc.2019-00072] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 03/27/2019] [Indexed: 12/31/2022]
Abstract
CONTEXT Mechanisms linking high and high-normal thyroid function to increased cardiovascular risk remain unclear. Hypothetically, coagulation can play a role. OBJECTIVE To investigate (i) the association of thyroid function with coagulation factors and (ii) whether coagulation factors mediate the association of thyroid function with cardiovascular disease (CVD). DESIGN AND SETTING Rotterdam Study, a population-based prospective study. PARTICIPANTS AND MAIN OUTCOME MEASURES In 5918 participants (mean age, 69.1 years), we measured TSH, free T4 (FT4), and coagulation factors [von Willebrand factor antigen (VWF:Ag), ADAMTS13 activity, fibrinogen]. Participants were followed up for the occurrence of cardiovascular events and deaths. Associations of thyroid function with coagulation factors (standardized z scores) and CVD were assessed through linear regression and Cox proportional hazards models, adjusted for potential confounders. We performed causal mediation analyses to evaluate whether the effect of thyroid function on CVD is mediated by coagulation. RESULTS Higher FT4 levels were associated with higher VWF:Ag (β = 0.34; 95% CI = 0.22, 0.47), lower ADAMTS13 activity (β = -0.22; 95%CI = -0.35, -0.09), and higher fibrinogen (β = 0.26; 95% CI = 0.13, 0.39); 857 incident cardiovascular events and 690 cardiovascular deaths occurred. FT4 levels were positively associated with cardiovascular events and deaths. The effect of FT4 on incident cardiovascular events was minimally mediated by fibrinogen (1.6%) but not by VWF:Ag and ADAMTS13. VWF:Ag and fibrinogen together mediated 10.0% of the effect of FT4 on cardiovascular deaths. CONCLUSIONS Higher FT4 levels were associated with higher VWF:Ag, lower ADAMTS13 activity, and higher fibrinogen levels, indicating a procoagulant state. VWF:Ag and fibrinogen explained up to 10% of the link between FT4 and CVD.
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Affiliation(s)
- Arjola Bano
- Department of Internal Medicine, Netherlands Academic Center for Thyroid Diseases, Erasmus Medical Center, Rotterdam, Netherlands
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, Netherlands
- Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
- Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Layal Chaker
- Department of Internal Medicine, Netherlands Academic Center for Thyroid Diseases, Erasmus Medical Center, Rotterdam, Netherlands
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, Netherlands
| | - Moniek P M de Maat
- Department of Hematology, Erasmus Medical Center, Rotterdam, Netherlands
| | - Ferdows Atiq
- Department of Hematology, Erasmus Medical Center, Rotterdam, Netherlands
| | - Maryam Kavousi
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, Netherlands
| | - Oscar H Franco
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, Netherlands
- Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
| | | | - Frank W G Leebeek
- Department of Hematology, Erasmus Medical Center, Rotterdam, Netherlands
| | - Robin P Peeters
- Department of Internal Medicine, Netherlands Academic Center for Thyroid Diseases, Erasmus Medical Center, Rotterdam, Netherlands
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, Netherlands
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Zaane BV, Romualdi E, Brandjes D, Gerdes V, Squizzato A, Stuijver D. The effect of hyperthyroidism on procoagulant, anticoagulant and fibrinolytic factors. Thromb Haemost 2017; 108:1077-88. [DOI: 10.1160/th12-07-0496] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 08/10/2012] [Indexed: 11/05/2022]
Abstract
SummarySeveral coagulation and fibrinolytic parameters appear to be affected by thyroid hormone excess;however, the net effect on the haemostatic system remains unclear. We aimed to update our previous review and systematically summarise and meta-analyse the data by assessing the effects of thyrotoxicosis on the coagulation and fibrinolytic system in vivo. Data sources included MEDLINE (2006–2012), EMBASE (2006–2012), and reference lists. The sources were combined with our previous search containing studies from 1980–2006. Eligible studies were all observational or experimental studies. Two investigators independently extracted data and rated study quality. Weighted mean proportion and 95% confidence intervals were calculated and pooled using a fixed and a random-effects model. A total of 29 articles consisting of 51 studies were included, as in several articles more than one study was described. We included four intervention (before and after treatment in hyperthyroid patients), five cross-sectional (hyperthyroid subjects and euthyroid controls), and four experimental (before and after use of thyroid hormone in euthyroid subjects) medium/high quality studies for meta-analysis. We found that thyrotoxicosis shifts the haemostatic balance towards a hypercoagulable and hypofibrinolytic state with a rise in factors VIII and IX, fibrinogen, von Willebrand factor, and plasminogen activator inhibitor-1. This was observed in endogenous and exogenous thyrotoxicosis, and in subclinical as well as overt hyperthyroidism. We conclude that both subclinical and overt hyperthyroidism induce a prothrombotic state, which is therefore likely to be a risk factor for venous thrombosis.
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Ordookhani A, Burman KD. Hemostasis in Hypothyroidism and Autoimmune Thyroid Disorders. Int J Endocrinol Metab 2017; 15:e42649. [PMID: 29026409 PMCID: PMC5626118 DOI: 10.5812/ijem.42649] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Revised: 02/11/2017] [Accepted: 02/15/2017] [Indexed: 02/06/2023] Open
Abstract
CONTEXT There are contradictory results on the effect of hypothyroidism on the changes in hemostasis. Inadequate population-based studies limited their clinical implications, mainly on the risk of venous thromboembolism (VTE). This paper reviews the studies on laboratory and population-based findings regarding hemostatic changes and risk of VTE in hypothyroidism and autoimmune thyroid disorders. EVIDENCE ACQUISITION A comprehensive literature search was conducted employing MEDLINE database. The following words were used for the search: Hypothyroidism; thyroiditis, autoimmune; blood coagulation factors; blood coagulation tests; hemostasis, blood coagulation disorders; thyroid hormones; myxedema; venous thromboembolism; fibrinolysis, receptors thyroid hormone. The papers that were related to hypothyroidism and autoimmune thyroid disorder and hemostasis are used in this review. RESULTS Overt hypothyroidism is more associated with a hypocoagulable state. Decreased platelet count, aggregation and agglutination, von Willebrand factor antigen and activity, several coagulation factors such as factor VIII, IX, XI, VII, and plasminogen activator-1 are detected in overt hypothyrodism. Increased fibrinogen has been detected in subclinical hypothyroidism and autoimmune thyroid disease rendering a tendency towards a hypercoagulability state. Increased factor VII and its activity, and plasminogen activator inhibitor-1 are among several findings contributing to a prothrombotic state in subclinical hypothyroidism. CONCLUSIONS Overt hypothyroidism is associated with a hypocoagulable state and subclinical hypothyroidism and autoimmune thyroid disorders may induce a prothrombotic state. However, there are contradictory findings for the abovementioned thyroid disorders. Prospective studies on the risk of VTE in various levels of hypofunctioning of the thyroid and autoimmune thyroid disorders are warranted.
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Affiliation(s)
- Arash Ordookhani
- Endocrine Section, Department of Internal Medicine, Providence Hospital, Washington, DC, 20017
| | - Kenneth D. Burman
- Endocrine Section, MedStar Washington Hospital Center, Washington, DC, 20010
- Corresponding author: Kenneth D. Burman, MD, The Endocrine Section, Rm. 2A72, MedStar Washington Hospital Center, 110 Irving St., NW, Washington, DC 20010. E-mail:
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Lippi G, Danese E, Montagnana M, Nouvenne A, Meschi T, Borghi L. Mean platelet volume is significantly associated with serum levels of thyroid-stimulating hormone in a cohort of older euthyroid subjects. Endocr Res 2015; 40:227-30. [PMID: 26167760 DOI: 10.3109/07435800.2015.1037392] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
PURPOSE This retrospective and observational study aimed to establish whether any relationship exists between the values of serum thyroid-stimulating hormone (TSH) and those of the mean platelet volume (MPV) in a large cohort of older euthyroid Italian subjects. MATERIALS AND METHOD The study population was represented by a cohort of 1,050 ostensibly healthy and euthyroid patients aged 50 years and older, who were referred for screening of thyroid disorders over a 1-year period. RESULTS A significant association was found between MPV and TSH values in both simple (r = 0.12; p < 0.001) and multivariable regression analysis (beta coefficient, 0.07; p < 0.001) after adjustment for age, sex, free thyroxin values and platelet count. After stratification of the study population according to quartiles of serum TSH levels, a graded increase of MPV values was found from the first to the fourth quartile of TSH (p = 0.013). The odds ratio for an increased MPV value of the fourth versus the first quartile of TSH was 1.54 (95% CI, 1.08-2.20; p = 0.017). CONCLUSIONS The results of this investigation demonstrate that a significant, positive and independent association exists between MPV and serum TSH values in a large cohort of older euthyroid Italian subjects.
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Affiliation(s)
- Giuseppe Lippi
- a Laboratory of Clinical Chemistry and Hematology , Academic Hospital of Parma , Parma , Italy
| | - Elisa Danese
- b Clinical Chemistry Section, Department of Life and Reproductive Sciences, Academic Hospital of Verona , Verona , Italy , and
| | - Martina Montagnana
- b Clinical Chemistry Section, Department of Life and Reproductive Sciences, Academic Hospital of Verona , Verona , Italy , and
| | - Antonio Nouvenne
- c Department of Clinical and Experimental Medicine , Academic Hospital of Parma , Parma , Italy
| | - Tiziana Meschi
- c Department of Clinical and Experimental Medicine , Academic Hospital of Parma , Parma , Italy
| | - Loris Borghi
- c Department of Clinical and Experimental Medicine , Academic Hospital of Parma , Parma , Italy
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Debeij J, van Zaane B, Dekkers OM, Doggen CJM, Smit JWA, van Zanten AP, Brandjes DPM, Büller HR, Gerdes VEA, Rosendaal FR, Cannegieter SC. High levels of procoagulant factors mediate the association between free thyroxine and the risk of venous thrombosis: the MEGA study. J Thromb Haemost 2014; 12:839-46. [PMID: 24679097 DOI: 10.1111/jth.12573] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 03/13/2014] [Indexed: 12/21/2022]
Abstract
BACKGROUND Thyroid hormone affects the coagulation system, but its effect on clinical disease is not clear. We determined the associations of levels of free thyroxine (FT4), thyroid-stimulating hormone (TSH) and anti-thyroid peroxidase antibodies (antiTPO) with levels of coagulation factors and the risk of venous thrombosis. METHODS In a large population based case-control study (Multiple Environmental and Genetic Assessment of risk factors for venous thrombosis study) on the etiology of venous thrombosis, we determined the levels of FT4, TSH, antiTPO, factor FII, FVII, FVIII, FIX, FX, von Willebrand factor (VWF), antithrombin, protein C, protein S and fibrinogen in 2177 cases and 2826 controls. RESULTS High levels of FT4 were associated with increased concentrations of procoagulant factors, and not with levels of anticoagulant factors. High levels of FT4 were also associated with the risk of venous thrombosis, up to an odds ratio (OR) of 2.2 (95% confidence interval [CI] 1.0-4.6) for levels above 24.4 pm relative to FT4 levels between 15.5 and 18.9 pm. In 11 cases and one control, clinical hyperthyroidism had been diagnosed within a year of the thrombotic event, leading to an OR of 17.0 (95% CI 2.2-133.0) for thrombosis. The ORs approached unity after adjustment for FVIII and VWF, which suggests that the effect was mediated by these factors. Low TSH levels were also, but less evidently, associated with thrombosis, whereas there was no association between antiTPO and venous thrombosis risk. CONCLUSIONS High levels of FT4 increase the concentrations of the procoagulant proteins FVIII, FIX, fibrinogen, and VWF, and by this mechanism increase the risk of venous thrombosis.
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Affiliation(s)
- J Debeij
- Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands
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Janovsky CCPS, Fukuda TG, Silva GS, Martins JRM. An unusual association between acute ischaemic stroke and cerebral venous thrombosis with thyrotoxic state. BMJ Case Rep 2013; 2013:bcr-2013-201130. [PMID: 24311416 DOI: 10.1136/bcr-2013-201130] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Arterial cerebral ischaemia has been described in different diseases of the thyroid. Likewise, cerebral venous thrombosis (CVT) has been reported in association with hyperthyroidism. However, the association of arterial and venous cerebral ischaemic events in patients with hyperthyroidism has not been previously described. We report the case of a patient with thyrotoxicosis who presented initially with an arterial ischaemic stroke complicated by a concomitant CVT, ultimately treated with decompressive craniectomy. Laboratory results revealed elevated factor VIII coagulant activity and a positive lupus anticoagulant IgG. In conclusion, CVT and arterial ischaemic events can happen concomitantly in patients with hyperthyroidism. Although there is insufficient evidence to prove that a hypercoagulability state in hyperthyroidism predisposes to cerebral ischaemia, the presence of antiphospholipid antibodies and other hypercoagulability studies should be performed in patients with thyrotoxicosis and ischaemic events.
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Debeij J, Dekkers OM, Asvold BO, Christiansen SC, Naess IA, Hammerstrom J, Rosendaal FR, Cannegieter SC. Increased levels of free thyroxine and risk of venous thrombosis in a large population-based prospective study. J Thromb Haemost 2012; 10:1539-46. [PMID: 22703181 DOI: 10.1111/j.1538-7836.2012.04818.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BACKGROUND Recent studies have shown that high levels of free thyroxine (FT4), even without leading to hyperthyroidism, are associated with a procoagulant state. OBJECTIVES The aim of our study was to determine whether high levels of thyroid hormones are associated with an increased risk of venous thrombosis. PATIENTS/METHODS From a prospective nested case-cohort design within the second Nord-Trøndelag Health Study (HUNT2) cohort (1995-1997; 66,140 subjects), all patients with venous thrombosis during follow-up (n=515) and 1476 randomly selected age-stratified and sex-stratified controls were included. Relative and absolute risks for venous thrombosis were calculated for different cut-off levels of thyroid hormones on the basis of percentiles in the controls and different times between blood sampling and thombosis. RESULTS In subjects with an FT4 level above the 98th percentile (17.3 pmol L(-1)), the odds ratio (OR) was 2.5 (95% confidence interval [CI] 1.3-5.0) as compared with subjects with levels below this percentile. For venous thrombosis within 1 year from blood sampling, this relative risk was more pronounced, with an OR of 4.8 (95% CI 1.7-14.0). Within 0.5 years, the association was even stronger, with an OR of 9.9 (95% CI 2.9-34.0, adjusted for age, sex, and body mass index). For thyroid-stimulating hormone, the relationship was inverse and less pronounced. The absolute risk within 6 months in the population for FT4 levels above the 98th percentile was 6.1 per 1000 person-years (95% CI 1.7-15.7). CONCLUSIONS Levels of FT4 at the upper end of the normal range are a strong risk factor for venous thrombosis. The risk increased with higher levels of thyroxine and shorter time between blood sampling and thrombosis. Further studies on the effect of clinical hyperthyroidism are warranted.
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Affiliation(s)
- J Debeij
- Clinical Epidemiology, Leiden University Medical Center, Leiden, the Netherlands
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Promberger R, Hermann M, Ott J. Hashimoto's thyroiditis in patients with normal thyroid-stimulating hormone levels. Expert Rev Endocrinol Metab 2012; 7:175-179. [PMID: 30764009 DOI: 10.1586/eem.12.3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Hashimoto's thyroiditis (HT) is one of the most common autoimmune endocrine disorders and often leads to hypothyroidism. It has been shown to substantially affect a patient's quality of life. Associated conditions and diseases were thought to be attributable to hypothyroidism. Yet, many patients still suffer from various symptoms even though all thyroid parameters are within the normal range. Independently of thyroid gland function, HT is associated with a wide range of organ-specific and non-organ-specific autoimmune disorders, as well as other diseases, including neuropsychological/psychiatric deficits, decreased left ventricular performance, disorders of the gut, fibromyalgia and reproductive health issues, among others. The underlying pathomechanisms remain unclear. Future treatment options might include thyroidectomy, selenium administration, prophylactic levothyroxine supplementation and dehydroepiandrosterone. However, further research is warranted to clarify the main pathophysiologic implications of thyroid autoimmunity and also to establish treatment options for euthyroid patients who suffer from HT-related symptoms and diseases.
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Affiliation(s)
- Regina Promberger
- a Department of Surgery, Kaiserin Elisabeth Spital, Huglgasse 1-3, 1150 Vienna, Austria
- b Department of Surgery, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - Michael Hermann
- a Department of Surgery, Kaiserin Elisabeth Spital, Huglgasse 1-3, 1150 Vienna, Austria
| | - Johannes Ott
- a Department of Surgery, Kaiserin Elisabeth Spital, Huglgasse 1-3, 1150 Vienna, Austria
- c Department of Gynecologic Endocrinology & Reproductive Medicine, Medical University Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria.
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Van Zaane B, Squizzato A, Debeij J, Dekkers OM, Meijers JCM, Van Zanten AP, Büller HR, Gerdes VEA, Cannegieter SC, Brandjes DPM. Alterations in coagulation and fibrinolysis after levothyroxine exposure in healthy volunteers: a controlled randomized crossover study. J Thromb Haemost 2011; 9:1816-24. [PMID: 21729238 DOI: 10.1111/j.1538-7836.2011.04430.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Several hemostatic abnormalities have been reported in hyperthyroidism, but the overall effect of thyroid hormone excess on coagulation and fibrinolysis is unclear. OBJECTIVE Our aim was to assess whether the use of supraphysiological doses of levothyroxine leads to coagulation activation and inhibition of fibrinolysis. PATIENTS AND METHODS Healthy volunteers were randomized to receive levothyroxine or no medication for 14 days with a washout period of at least 28 days in a crossover design. To study the effects of different degrees of thyroid hormone excess, 16 participants received levothyroxine in a dose of 0.3 mg per day, and 12 received levothyroxine 0.45 or 0.6 mg per day depending on body weight. Several variables of coagulation and fibrinolysis were measured. RESULTS Levels of von Willebrand factor activity (VWF:RiCo) and antigen (VWF:Ag), factor (F) VIII, plasminogen activator inhibitor-1 (PAI-1) and clot-lysis time were slightly higher after levothyroxine 0.3 mg per day than after the control situation, but only levels of VWF showed a significant increase from baseline. After levothyroxine 0.45 or 0.6 mg per day, levels of fibrinogen increased by 17%, VWF activity by 24%, VWF antigen by 26%, FVIII by 19%, FIX by 14%, FX by 7%, PAI-1 by 116% and clot-lysis time by 14%, and activated partial thromboplastin time decreased by 3%; all were significant changes compared with the control situation. We did not observe clear evidence of coagulation activation. CONCLUSIONS Our data suggest that thyroid hormone excess increases coagulation factor levels and inhibits fibrinolysis in a dose-dependent fashion. This implies an increased risk of venous thrombosis during hyperthyroidism.
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Affiliation(s)
- B Van Zaane
- Department of Internal Medicine, Slotervaart Hospital, Amsterdam, the Netherlands.
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Franchini M, Lippi G, Targher G. Hyperthyroidism and venous thrombosis: a casual or causal association? A systematic literature review. Clin Appl Thromb Hemost 2010; 17:387-92. [PMID: 20308227 DOI: 10.1177/1076029610364521] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A kaleidoscope of coagulation disorders have been reported in patients with thyroid dysfunctions. Globally, these disorders involve both primary and secondary hemostasis and range from subclinical laboratory abnormalities to, more rarely, life-threatening hemorrhages or thrombotic events. While overt hypothyroidism appears to be associated with a bleeding tendency, hyperthyroidism emerged to have an increased risk of thrombotic events. In particular, a number of case reports have documented acute venous thrombosis complications in patients with overt hyperthyroidism, especially at cerebral sites. Nevertheless, further observational and intervention studies might be needed to provide a more definitive information on the clinical relevance of this association, along with the potential implication for prevention and treatment of coagulation-fibrinolytic abnormalities in patients with thyroid dysfunction.
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Affiliation(s)
- Massimo Franchini
- Immunohematology and Transfusion Center, Department of Pathology and Laboratory Medicine, University Hospital of Parma, Parma, Italy.
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