High Risk For Thrombotic Events Research Articles

Interleukin-1-Beta and Dyslipidemic Syndrome as Major Risk Factors for Thrombotic Complications in Type 2 Diabetes Mellitus

Diabetes mellitus (DM) is a complex disease characterized by chronic hyperglycemia, a known risk factor for accelerated atherosclerosis and vascular disease. The aim of this study was to show that the connection between DM and other risk factors, such as dyslipidemia, inflammatory phenomena, or the development of certain vascular injuries, leads to a high frequency of thrombotic events in diabetic patients compared to the nondiabetic population. The study included one hundred eighty patients divided in the following groups: diabetic without ischemic cardiopathy-related disorders (DM), diabetic with clinical or off-clinical (electrocardiogram, cardiac ultrasound) ischemic cardiopathy-related disorders (DM + IC), and nondiabetic with ischemic cardiopathy-related disorders (IC). We investigated the following parameters: von Willebrand Factor, HDL-cholesterol, LDL-cholesterol, interleukin-1-beta, protein C, and plasminogen activator inhibitor type 1. The results achieved in our study have revealed the highest thrombotic risk among the groups of diabetic patients, which is in direct correlation with the high values of interleukin-1-beta and the modifications of lipid parameters, acknowledging the data in the literature, according to which hyperglycemia alters endothelial functions directly and indirectly by synthesis of growth factors and cytokines and generates metabolic disorders which would explain the high risk for thrombotic events.

Desmopressin-related myocardial infarction in a patient with Wegener's granulomatosis: A case report and review of the literature

Desmopressin is a synthetic vasopressin analog that increases the plasma levels of coagulation factor VIII, von Willebrand factor, and tissue plasminogen activator. This hemostatic agent, which can be administered either parenterally or intranasally, has been approved for use in the prevention and treatment of hemorrhagic events during surgery in patients with hemophilia A, in cases of prolonged idiopathic bleeding, and for complications associated with platelet antiaggregant therapy. This case report describes cardiac toxicity associated with desmopressin administered according to the recommended indications: a 55-year-old woman diagnosed with Wegener's granulomatosis (WG) was treated with desmopressin to improve hemostasis and shorten bleeding time before a planned renal biopsy. She developed cardiac arrest within 60 minutes of the desmopressin injection. Cardiopulmonary resuscitation began immediately and was successful, although the patient subsequently died of WG-associated complications. Desmopressin administration thus appears, in some cases, to be associated with a high risk of thrombotic events, possibly by stimulating the rapid release of endothelial factors such as an abnormal multimeric form of von Willebrand factor, which might cause platelet aggregation. Clinicians should be aware of the possible occurrence of this little-known but potentially serious cardiac event associated with desmopressin administration and be prepared to initiate cardiopulmonary resuscitation immediately if needed.

Essential Thrombocythaemia in Young Adults: Clinical Characteristics and Outcomes – a Single Center Experience

Abstract 5060Less than 20% of patients with essential thrombocythemia (ET) are diagnosed below the age of 60. Patients with ET have increased risk of thrombosis and bleeding and potential for progression to myelofibrosis (MF) or acute myeloid leukaemia (AML). In limited studies of young patients, the clinical course has been relatively benign with low rates of transformation to AML or MF. Thrombohemorrhagic events are generally few, but higher than that of the general population. This study aims to characterize of a group ET patients diagnosed at age ≤40, their thrombotic and hemorrhagic events, disease progression and treatment given.Patients were identified through a single institution MPN registry. This is an IRB approved registry that captures comprehensive information about patients with ET. Data on patient demographics, treatment, and disease-related events were obtained. Patients were diagnosed from 1975–2011, using either WHO or PVSG criteria depending on date of diagnosis. Kaplan-Meier method was used for survival analysis.59 patients were diagnosed with ET at age ≤40. Median age of diagnosis was 31. 5years (range 16–40), with a median follow up of 7. 7years (0. 4–33. 8). All were of Asian descent: 81. 4% Chinese, 11. 9% Malay, 3. 4% Indian and 3. 4% Filipino. 40. 7% were male. JAK2 V617F mutation was screened for in 61%. Of these patients, 11 were positive, 25 negative for the mutation. Mean presenting counts were: WBC 10. 7 × 109/L (5. 9–21. 3), Hb 13. 6g/dL (9. 7–16. 4), platelets 957 × 109/L (449–2377). Splenomegaly was noted in 3 patients. 20. 3% had underlying hypertension, 16. 9% hyperlipidemia and 5. 1% diabetes mellitus. One patient had a prior stroke. Another had prior portal vein thrombosis.At diagnosis, 23. 7% were symptomatic, with microvascular symptoms of headache (11. 9%) and giddiness (6. 8%) being most common. The remainder were diagnosed incidentally, on health screening or when seeking medical attention for unrelated conditions. One patient presented with a myocardial infarction at diagnosis, while another had a significant bleeding post hemorrhoidectomy with drop in Hb by >2g/dL (platelet 2457 × 109/L). Based on a history of prior thrombosis, 3 patients were defined as high risk for thrombotic events. 67. 8% of patients had cytoreduction, indications being platelets ≥1500 × 109/L (n=16), presence of risk factors for atherosclerotic disease (n=11) and history/onset of thrombosis (n=5). In 8, the reason for cytoreduction could not be ascertained. Hydroxyurea was most commonly used (62. 7%), followed by anagrelide in 52. 5% and interferon 25. 4%. 5. 1% received busulphan, and 1. 7% 32P. Use of antiplatelet therapy was noted in 83. 8%, most frequently aspirin (76. 5%) and ticlopidine (11. 9%). On follow up, 2 arterial thromboses occurred (stroke, TIA), giving a thrombosis rate of 0. 39%/patients/year. Neither was a recurrent thrombosis. No venous thrombosis or major bleeds occurred. 20. 4% had minor mucocutaneous bleeding; 5 had platelets ≥1500 × 109/L at that time. 3. 4% had disease progression due to MF and another 3. 4% had AML. 3. 4% of patients died due to AML. Median survival was 33. 8years (95% confidence interval 30. 3–35. 5). Initial blood counts, presence of JAK2 and high risk disease status did not correlate with thrombotic risk, risk of death or disease progression. Use of antiplatelet agents and a platelet count ≥1500 × 109/L did not correlate with bleeding risk.Few studies have looked exclusively at young patients with ET. In this group, most patients were asymptomatic and well, ET being diagnosed incidentally. They were predominantly at low risk for thrombosis and other ET-related complications. The period of follow up was comparable to that of other studies and during that time, the rate of complications and risk of disease progression was low. The thrombosis rate of 0. 39% per patient year was less than that reported by other groups (2. 2–2. 6 thromboses/100patients/year) (Leukaemia 2007;21:1218–1223, Clin Appl Thrombosis/Hemostasis 2000;6(1):31–35) but similar to the 0. 74%/patient year reported by Barbui (Blood. Epub. June 13 2012). Overall findings generally complemented those reported by other groups. No risk factors were found to influence the occurrence of complications, but the number of events was small. Follow up of this group of patients over time is essential to see if their disease course remains benign or if complications will increase with time.Soli Deo Gloria Disclosures:Kam:Shire Pharmaceuticals: Consultancy, grant to support the MPN registry Other.

Recent combined hormonal contraceptives (CHCs) and the risk of thromboembolism and other cardiovascular events in new users

BackgroundCombined hormonal contraceptives (CHCs) place women at increased risk of venous thromboembolic events (VTEs) and arterial thrombotic events (ATEs), including acute myocardial infarction and ischemic stroke. There is concern that three recent CHC preparations [drospirenone-containing pills (DRSPs), the norelgestromin-containing transdermal patch (NGMN) and the etonogestrel vaginal ring (ETON)] may place women at even higher risk of thrombosis than other older low-dose CHCs with a known safety profile. Study DesignAll VTEs and all hospitalized ATEs were identified in women, ages 10–55 years, from two integrated health care programs and two state Medicaid programs during the time period covering their new use of DRSP, NGMN, ETON or one of four low-dose estrogen comparator CHCs. The relative risk of thrombotic and thromboembolic outcomes associated with the newer CHCs in relation to the comparators was assessed with Cox proportional hazards regression models adjusting for age, site and year of entry into the study. ResultsThe hazards ratio for DRSP in relation to low-dose estrogen comparators among new users was 1.77 (95% confidence interval 1.33–2.35) for VTE and 2.01 (1.06–3.81) for ATE. The increased risk of DRSP was limited to the 10–34-year age group for VTE and the 35–55-year group for ATE. Use of the NGMN patch and ETON vaginal ring was not associated with increased risk of either thromboembolic or thrombotic outcomes. ConclusionsIn new users, DRSP was associated with higher risk of thrombotic events (VTE and ATE) relative to low-dose estrogen comparator CHCs, while the use of the NGMN patch and ETON vaginal ring was not.

Possible high risk of thrombotic events in patients with paroxysmal nocturnal haemoglobinuria after discontinuation of eculizumab

Possible high risk of thrombotic events in patients with paroxysmal nocturnal haemoglobinuria after discontinuation of eculizumab

Abstract 18113: High Exercise-Induced Platelet Reactivity in Patients with Fabry Disease

Background: Cerebrovascular events represent a major cause of disability in young patients with Fabry disease (FD). However the pathogenesis of cerebrovascular events in these patients is not fully understood and prevention, besides enzyme replacement therapy (ERT), is empirically based on antiplatelet drugs. We evaluated platelet function in patients with FD without evidence of coronary or carotid atherosclerosis. Methods: Fifteen patients with genetically confirmed FD (mean age 42, 6 F) underwent treadmill exercise stress test (EST). Platelet reactivity was assessed by flow cytometry at baseline and at peak EST, with and without ADP stimulation, by measuring monocyte-platelet aggregate (MPA) formation (expressed as percentage of monocyte binding platelets) and CD41 expression (assessed as mean fluorescence intensity). All patients underwent carotid ultrasound and coronary angiography to rule out carotid or coronary artery disease. Patients on ERT were submitted to EST the day before drug infusion. Thirty healthy sex- and age-matched subjects were studied as controls. Results: Coronary angiography and carotid ultrasound showed no evidence of atherosclerosis in all FD patients; EST showed signs of ischemia in 3 patients with FD cardiomyopathy. Thirteen patients were on ERT at the time of the study. Compared to resting values, MPA and CD41 expression,with and without ADP stimulation, significantly increased after exercise in the FD group but not in controls. Exercise-induced values of MPA (20.1vs18.7, p=0.001 - with ADP:25.2vs22.0, p<0.0001) and CD41 expression (20.3vs19.4 p=0.006 - with ADP:26.1vs21.9, p<0.0001) were higher in FD patients than in controls, while resting values didn't significantly differ. Conclusions: High exercise-induced platelet reactivity has been reported in patients at high risk for thrombotic events, like those with coronary or peripheral atherosclerosis. In this study we found high exercise-induced platelet reactivity in patients with FD, suggesting that enhanced platelet reactivity may contribute to the pathogenesis of cerebrovascular events in these patients. Our data support the inclusion of antiplatelet drugs in conventional therapy for FD. The effect of ERT on platelet function remains to be clarified.

Progestin-Only Contraceptives and the Risk of Venous Thromboembolism: Systematic Review and Meta-Analysis,

Abstract 3344 Background:Combined oral contraceptives (COC) containing estrogens and progestins are associated with a 2 to 4-fold increased risk of venous thromboembolic events. Progestin-only contraceptives are commonly prescribed to women with a higher risk for thrombosis, although a lower thrombotic risk than COC has not been clearly established. We performed a systematic review and meta-analysis of published studies to estimate the risk ratio of venous thromboembolism (VTE) in women taking progesterone for the purpose of contraception. Materials and methods:We performed a literature search of cohort, case-control and randomized studies including women treated with progestin-only contraception compared with a no-hormone control group. All administration routes (oral, injectable and intra-uterine) were considered. The primary endpoint was the corrected risk ratio of VTE analyzed using a random effects model. Results:1150 references were retrieved; 7 studies were retained for analysis. The summary estimate of the adjusted risk ratio of VTE for women taking a progestin for contraception versus no hormone was 1.02 (95% CI=0.76–1.37, p=0.89). Heterogeneity between studies was minimal (Q-value=7.1, I2=15.49 and p=0.31). An analysis combining the unadjusted odds ratios of VTE gave a similar result (OR=1.24, 95% CI=0.93–1.66, p=0.14). Analysis by subgroup suggests a higher risk of thrombotic events for individuals using an injectable progestin, with an estimated risk ratio of VTE equal to 2.67 (95% CI=1.29–5.53, p=0.008), compared to 0.87 (95% CI=0.53–1.42, p=0.58) for oral administration. Conclusions:Progestin-only oral formulations used for contraception do not appear to increase the risk of venous thromboembolic disease, although injectable administration was associated with an increased incidence of VTE relative to women not taking hormones that is comparable to the risk associated with COC.StudyFormatDrug Formulation(s)Number of PatientsAdjusted Risk Ratio of VTE (95% CI)‡ProgestinNo HormoneVTENo VTEVTENo VTE1. Barsoum et al, Thromb Res 2010case-controlO, I32981331.20 (0.40–3.62)2. Conard et al, Contraception 2004retrospective cohortO3996960.80 (0.18–3.53)3. Heinemann et al, Eur J Contracept Reprod Health Care 1999case controlO75417413460.68 (0.28–1.66)4. Lidegaard et al, BMJ 2009retrospective cohortO,U49N/A*2168N/A†0.82 (0.62–1.08)5. Vasilakis et al, Lancet 1999case-controlO, I226131611.30 (0.27–6.19)6. Vlieg et al, Arterioscler Thromb Vasc Bio 2010case-controlI, U234142111021.38 (0.65–2.90)7. WHO, Contraception 1998case-controlO, I329863522881.93 (0.97–3.84)Table Legend: O=oral, I=injectable, U=intra-uterine.*VTE incidence rate/10000 woman years =1.82 to 3.35, depending on the type of progestin.†VTE incidence rate/10000 woman years =3.01 for non-users.‡Odds ratios and rate ratios were treated as risk ratios because of the low prevalence of disease. [Display omitted] Estimated risk ratio of VTE for progestin versus no hormone, using adjusted values; A, all routes of administration for all studies; B, injectable progestins only, for studies where those results were reported.This publication was supported by Grant Number UL1 RR025752 from the National Center for Research Resources. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NCRR. Disclosures:No relevant conflicts of interest to declare.

Risk Factors for Thrombosis in WHO-Defined Early/Prefibrotic Myelofibrosis: An International Study of 264 Patients,

Abstract 3846▪▪This icon denotes a clinically relevant abstract INTRODUCTIONThere is strong evidence indicating that the clear-cut separation of prefibrotic primary myelofibrosis (PMF) from essential thrombocythemia (ET) by consequent application of the World Health Organization (WHO) 2008 criteria is reflected in different, well defined clinical pictures and divergent prognoses (Barbui et al, JCO 2011,Thiele et al, Blood 2011). Very recently the specific risk profile for arterial and venous thrombosis in WHO- diagnosed ET was published (Carobbio et al, Blood 2011). In PMF so far all published data on vascular events were exclusively based on overt disease manifestations until now there are no data available regarding prefibrotic stages. Consequently, we aimed to evaluate the corresponding risk profile of patients with WHO-diagnosed prefibrotic PMF. METHODSA total number of 264 patients with WHO-defined prefibrotic PMF derived from either the Medical University of Vienna or an International Database (Barbui et al, JCO 2011) were studied. Nonfatal thrombotic events considered in this study were reported as rates per 100 patient-years and included transient ischemic attacks, thrombotic cerebrovascular accidents, coronary artery disease, myocardial infarction, peripheral arterial disease, deep vein thrombosis of peripheral vasculature, pulmonary embolism, and abdominal large vein thrombosis. Cardiovascular risks factors considered, comprised of arterial hypertension, diabetes mellitus and tobacco use. To evaluate risk factors for total thrombosis and for arterial and venous events in particular multivariate Cox- regression analysis including the co-variables sex, age, previous thrombotic event, laboratory parameters measured at diagnosis and need for cytoreductive and/or antiplatelet therapy during follow-up was calculated. P values less than 0.05 were considered as statistically significant. RESULTSAfter a median follow- up of 5.8 years (range0.0 – 27.2), the total rate of non fatal thrombotic events was 2.1% patient-years (95% CI, 1.5–2.8); the incidence of arterial events was higher (1.7% patient- years) than of venous events (0.6% patient-years).Considering thrombosis in general a higher white blood cell (WBC) count enhances the risk significantly (p=0.005; HR 1.15). This is also true in arterial events in particular (p=0.047; HR 1.12). A lower platelet count is associated with a higher risk for thrombotic events; for thrombosis in general this association is of borderline significance (p=0.056; HR 0.99), for arterial thrombosis in particular of significance (p= 0.042; HR 0.99). A lower hemoglobin level is associated with a higher risk for venous thrombosis (p=0.007; HR 0.59). CONCLUSIONLeukocytosis appears as a risk factor for thrombosis in general and also for arterial thrombosis in particular in WHO-diagnosed prefibrotic PMF. Moreover, higher platelet counts seem to decrease significantly the risk for thrombotic events in general and arterial thrombosis in particular. Anemia is associated with a higher risk for venous thrombosis. These observations are partly in line with recently published findings in WHO-diagnosed ET (Carobbio et al,2011) and might indicate the existence of a specific risk profile for thrombotic events in prefibrotic PMF. This is the first study reporting data on the risk profile for thrombosis in WHO-diagnosed prefibrotic PMF. Certainly these findings ask for validation in a larger patient population. Disclosures:Gisslinger:Novartis: Speakers Bureau; Celgene Austria: Research Funding, Speakers Bureau; AOP-Orphan Pharmaceuticals AG: Speakers Bureau. Vannucchi:Novartis: Honoraria.

No evidence for an association of AB0 blood group and manifestation of thrombotic microangiopathies

[1] Abhayaratna WP, Seward JB, Appleton CP, et al. Left atrial size: physiologic determinants and clinical applications. J Am Coll Cardiol 2006;47:2357–63. [2] Drager LF, Bortolotto LA, Pedrosa RP, Krieger EM, Lorenzi-Filho G. Left atrial diameter is independently associated with arterial stiffness in patients with obstructive sleep apnea: potential implications for atrial fibrillation. Int J Cardiol 2010;144:257–9. [3] Mancia G, De Backer G, Dominiczak A, et al. The Task Force for the Management of Arterial Hypertension of the European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC). J Hypertens 2007;25:1105–87. [4] Williams B, Lacy PS, Thom SM, et al. Differential impact of blood pressurelowering drugs on central aortic pressure and clinical outcomes: principal results of the Conduit Artery Function Evaluation (CAFE) study. Circulation 2006;113:1213–25. [5] Vlachopoulos C, Aznaouridis K, Stefanadis C. Prediction of cardiovascular events and all-cause mortality with arterial stiffness: a systematic review and meta-analysis. J Am Coll Cardiol 2010;55:1318–27. [6] Kang S, Fan HM, Li J, et al. Relationship of arterial stiffness and early mild diastolic heart failure in general middle and aged population. Eur Heart J 2010;31:2799–807. [7] Lang RM, Bierig M, Devereux RB, et al. Recommendations for chamber quantification: a report from the American Society of Echocardiography's Guidelines and Standards Committee and the Chamber Quantification Writing Group, developed in conjunction with the European Association of Echocardiography, a branch of the European Society of Cardiology. J Am Soc Echocardiogr 2005;18:1440–63. [8] Allessie MA, Konings K, Kirchhof CJ, Wijffels M. Electrophysiologic mechanisms of perpetuation of atrial fibrillation. Am J Cardiol 1996;77:10A–23A. [9] Dickstein K, Cohen-Solal A, Filippatos G, et al. ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure 2008: the Task Force for the Diagnosis and Treatment of Acute and Chronic Heart Failure 2008 of the European Society of Cardiology. Developed in collaboration with the Heart Failure Association of the ESC (HFA) and endorsed by the European Society of Intensive Care Medicine (ESICM). Eur Heart J 2008;29:2388–442. [10] Fuster V, Ryden LE, Cannom DS, et al. 2011 ACCF/AHA/HRS focused updates incorporated into the ACC/AHA/ESC 2006 Guidelines for the management of patients with atrial fibrillation: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines developed in partnership with the European Society of Cardiology and in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society. J Am Coll Cardiol 2011;57:e101–98. [11] Ommen SR, Nishimura RA, Appleton CP, et al. Clinical utility of Doppler echocardiography and tissue Doppler imaging in the estimation of left ventricular filling pressures: a comparative simultaneous Dopplercatheterization study. Circulation 2000;102:1788–94.

Chemotherapy-associated thromboembolic risk in cancer outpatients and effect of nadroparin thromboprophylaxis: results of a retrospective analysis of the PROTECHT study

BackgroundCancer patients receiving chemotherapy are at increased risk of thrombosis. Nadroparin has been demonstrated to reduce the incidence of venous and arterial thrombotic events (TEs) by about 50% in cancer outpatients receiving chemotherapy. The aims of this retrospective analysis were to evaluate the thromboembolic risk and the benefit of thromboprophylaxis according to type of chemotherapy.MethodsCancer outpatients were randomly assigned to receive subcutaneous injections of nadroparin or placebo. The incidence of symptomatic TEs was assessed according to the type of chemotherapy. Results were reported as risk ratios with associated 95% CI and two-tailed probability values.Results769 and 381 patients have been evaluated in the nadroparin and placebo group, respectively. In the absence of thromboprophylaxis, the highest rate of TEs was found in patients receiving gemcitabine- (8.1%) or cisplatin-based chemotherapy (7.0%). The combination of gemcitabine and cisplatin or carboplatin increased the risk to 10.2%. Thromboprophylaxis reduced TE risk by 68% in patients receiving gemcitabine; with a further decrease to 78% in those receiving a combination of gemcitabine and platinum.ConclusionsThis retrospective analysis confirms that patients undergoing chemotherapy including gemcitabine, platinum analogues or their combination are at higher risk of TEs. Our results also suggest that outpatients receiving chemotherapy regimens including these agents might achieve an increased benefit from thromboprophylaxis with nadroparin. Clinical Trial registration number: NCT 00951574

Hypercholesterolemia and chronic ischemia alter myocardial responses to selective cyclooxygenase-2 inhibition

Cyclooxygenase-2 inhibitors have been implicated in adverse cardiac events. We hypothesize that hypercholesterolemia and ischemia may alter the myocardial response to the cyclooxygenase-2 inhibitor celecoxib. Yorkshire swine fed normal chow (CX, n = 6) or high-cholesterol diet (HCX, n = 6) underwent placement of an Ameroid constrictor on the left circumflex artery and were started on celecoxib (200 mg/day). After 7 weeks, ischemic and nonischemic myocardium was analyzed for thrombogenic ratio (thromboxane content divided by prostacyclin content), total protein oxidative stress, and expression of prostacyclin synthase, thromboxane synthase, myeloperoxidase, and superoxide dismutase. Cardiac function, tissue perfusion, and vessel density were measured. HCX animals were significantly hypercholesterolemic compared with CX animals. Thrombogenic ratio was significantly higher in the HCX group than in the CX group, but prostacyclin and thromboxane synthase expression was similar in all tissues. Myocardial perfusion was decreased in the HCX group compared with the CX group. Total oxidative stress, myeloperoxidase, and superoxide dismutase were increased in ischemic tissue compared with nonischemic tissues, but there was no diet-induced difference between groups. There was no difference in capillary or arteriolar density between groups. Left ventricular contractility was greater in the HCX group than in the CX group, but there was no significant difference in heart rate, mean arterial pressure, or left ventricular pressure. Hypercholesterolemic patients using celecoxib may be at higher risk for thrombotic events than those with normal cholesterol, but the relationship between dyslipidemia, ischemia, and cyclooxygenase-2 inhibition is likely much more complicated than originally thought.

JAK2 mutation status, hemostatic risk factors and thrombophilic factors in essential thrombocythemia (ET) patients

The recently discovered JAK2 V617F point mutation, found in 50-60% of ET patients, has been reported to be associated with a higher risk of thrombotic events. In this study, we explored if JAK2 V617F mutation, or coexisting thrombophilic and hemostatic risk factors, contributed to these complications. We examined 32 patients with ET, and looked for pathogenetic JAK2 V617F mutation and prothrombotic genes mutations: factor V Leiden, prothrombin and MTHFR. We also evaluated plasma levels of fibrinogen, factors VIII and XII, AT, protein C, protein S and serum level of homocysteine. Urokinase concentration was assessed in patients' plasma as well as platelet lysates. There was no difference in the number of thrombotic complications between ET patients with and without JAK2 mutation. However, we found a number of thrombophilic and hemostatic risk factors that could contribute to thrombotic complications in ET patients.

Hemorrhagic and Thrombotic Events Associated with Generic Substitution of Warfarin in Patients with Atrial Fibrillation: A Retrospective Analysis

Substitution of generic warfarin for imprint warfarin (Coumadin; DuPont/Bristol-Myers Squibb) has been a controversial issue due to bioavailability and bioequivalence concerns. To assess the risk of thrombotic and hemorrhagic events following substitution of warfarin formulations in patients with atrial fibrillation (AF). Historical cohort analysis was performed using a commercial insurance claims database. Adults with a diagnosis of AF between January 2003 and December 2007, with 16 or more months of continuous eligibility, a warfarin prescription within 30 days after index AF diagnosis, and at least 3 warfarin prescription fills during the follow-up period were included. Individuals with AF diagnosis or warfarin prescription during the pre-index period were excluded. Cox proportional hazard regression models controlling for sex and baseline comorbidities (Charlson comorbidity index, CCI) were used to evaluate the risks of thrombotic and hemorrhagic events following warfarin formulation switches. Of 37,756 subjects included in the analysis (mean age 70.96 years, 42.3% females), 12,996 (34.4%) switched warfarin formulations, 20,292 (53.7%) used only 1 generic product, and 4468 (11.8%) used only Coumadin during follow-up. Compared with continued use of Coumadin, switching from that product to the generic formulation was associated with a significantly higher risk of thrombotic events (HR = 1.81; 95% CI 1.42 to 2.31). Similar findings were observed for switching from generic warfarin to Coumadin (HR = 1.76; 95% CI 1.35 to 2.30), and from 1 generic to another generic product (HR = 1.89; 95% CI 1.57 to 2.29). Similarly, switching from Coumadin to generic warfarin (HR = 1.51; 95% CI 1.17 to 1.93), generic warfarin to Coumadin (HR = 1.60; 95% CI 1.23 to 2.1), and from 1 generic to another generic product (HR = 1.74; 95% CI 1.45 to 2.11) were associated with significantly higher risk of hemorrhage than remaining on Coumadin. Switching warfarin formulations exposed patients with AF to a higher risk of bleeding events compared to remaining on a single product. Maintaining patients on a product with consistent bioavailability may optimize the risk-benefit balance of anticoagulation therapy.

Risk Factor Profiles of Stroke, Myocardial Infarction, and Atrial Fibrillation: A Japanese Multicenter Cooperative Registry

We sought to clarify risk factor profiles and current treatment of Japanese patients with stroke, myocardial infarction (MI), and nonvalvular atrial fibrillation (NVAF) using the database of the Japan Thrombosis Registry for Atrial Fibrillation, Coronary, or Cerebrovascular Events (J-TRACE). J-TRACE is a nationwide multicenter cooperative cohort of Japanese patients with MI, stroke, and NVAF. Baseline characteristics of 8087 Japanese patients (5804 male, average age 68.7 years) with history of stroke (n=3554), MI (n=2291), or NVAF (n=2242) were analyzed. History of stroke (14.7%) was more frequent than history of MI (2.6%) in patients with stroke, whereas history of stroke (6.6%) was less frequent than history of MI (7.6%) in patients with MI. In patients with NVAF, history of stroke (14.3%) was far more frequent than history of MI (3.4%). Hypertension was more frequent in stroke (74.4%) than MI (62.0%) or NVAF (57.7%), whereas hypercholesterolemia, diabetes mellitus, and cigarette smoking were more prevalent in patients with MI (56.1%, 35.1%, and 33.3%, respectively) than in those with stroke (35.7%, 22.4%, and 19.7%, respectively) or NVAF (26.9%, 17.2%, and 16.1%, respectively). Alcohol consumption (34.9%) and obesity (body mass index>25) (32.8%) were most common in patients with NVAF. In all patients, nonmedication rates were higher in patients with hypercholesterolemia (29.8%) or diabetes (36.9%) than in those with hypertension (9.5%). Warfarin was used in 58.9% of patients with low-risk and 75.4% with high-risk NVAF. Risk factor profiles and their modification were not similar among patients in Japan with MI, stroke, and NVAF, although they share a high risk of thrombotic events.

Impact of P2Y12-ADP receptor polymorphism on the efficacy of clopidogrel dose-adjustment according to platelet reactivity monitoring in coronary artery disease patients

Introduction High on-treatment platelet reactivity (HTPR) after clopidogrel loading dose (LD) is associated with a high risk of thrombotic events after percutaneous coronary intervention(PCI). We have demonstrated that HTPR could be overcome in the majority of cases using LD adjustment resulting in an improved clinical outcome. However this strategy failed in nearly 10% of patients with HTPR. We aimed to determine if P2Y12-ADP receptor polymorphisms were associated with failed dose adjustment. Materiel and method Forty-three patients undergoing PCI were included in this prospective study. A VASP index ≥ 50% after a 600 mg LD of clopidogrel defined HTPR. Dose adjustment was performed according to PR monitoring to reach a VASP index < 50%. Genetic polymorphism of the P2Y12-ADP receptor was determined by direct sequencing. Results Patients with successful dose-adjustment (SDA) (n = 33) and failed (FDA) (n = 10) dose-adjustment groups were compared. The 2 groups were similar in terms of cardiovascular risk factors including diabetes mellitus (SDA vs FDA: 42 vs 20%; p = 0.3). The prevalence of the H2 allele of the P2Y12-ADP receptor was also similar between the 2 groups (p = 0.3). The H2 allele was found in 6 patients which are all included in the SDA group. After the first 600 mg loading dose of clopidogrel, patients carrying at least one H2 allele had similar VASP index compared to those carrying two copies of the wild type allele (H1) (SDA vs FDA: 44.9 ± 14.9 vs 43.5 ± 10%; p = 0.8). Conclusion The present study suggests that the H2 allele of the P2Y12-ADP receptor is not involved in clopidogrel failed dose adjustment according to platelet reactivity monitoring.

Risk of Arterial Thrombotic Events in Inflammatory Bowel Disease

Patients with inflammatory bowel disease (IBD) have an increased risk of venous thrombotic events. The risk of arterial thrombotic events in IBD, however, has been less well characterized. We explored whether Crohn's disease (CD) and ulcerative colitis (UC) are associated with a higher risk for thrombotic events involving the mesenteric, cardiac, or cerebral arteries. Using the Thomson Reuters MarketScan Research claims database, we conducted a retrospective cohort study of IBD patients observed for the occurrence of pre-defined thrombotic events. For comparison, four non-IBD controls were age-, sex-, and index date-matched to each IBD case. The outcomes of interest were acute mesenteric ischemia, transient ischemic attack, cerebrovascular occlusion, atherosclerosis, peripheral vascular disease, and myocardial infarction. We performed a multivariate analysis adjusting for potential confounders for thrombotic events, including hypertension, diabetes, hyperlipidemia, and, in women, the use of contraceptives. We calculated the adjusted hazard ratios (HRs) for each event by comparing IBD patients with controls and used the log-rank test to determine statistical significance. The study included 17,487 IBD patients and 69,948 controls. Overall, IBD patients had a markedly increased risk of acute mesenteric ischemia (HR=11.2, P<0.001). IBD patients as a whole did not have an increased risk of other arterial thrombotic events, including myocardial infarction and transient ischemic attack, when compared with controls. However, women with IBD who were over the age of 40 years had a higher risk of myocardial infarction (HR=1.6, P=0.003). In addition, women with IBD below the age of 40 years who showed a significantly higher risk for stroke (HR=2.1, P=0.04). For all events, the risks in CD and UC were similar. Patients with IBD have a markedly increased risk of acute mesenteric ischemia. Subgroup analysis reveals that women over the age of 40 years with IBD are at increased risk of myocardial infarction, whereas those below the age of 40 years exhibit a two-fold higher risk for stroke. In contrast, men with IBD did not share these same risks for arterial thrombotic events.

Clinical and Functional Correlates of Platelet Cyclic GMP in Essential Hypertensives

Platelets play a central role in atherothrombosis, which is responsible of major cardiovascular complications in human hypertension. Nitric oxide (NO) inhibits platelet aggregation via the second messenger cyclic guanosine monophosphate (cGMP). In essential hypertensives (EHs), we examined the relationship between platelet cGMP and clinical, hemodynamic, humoral variables as well as the responses to aggregating agents. In untreated EHs (male/female 106/43, age 44.4 +/- 1.1 years, smokers yes/no 38/111), blood pressure (BP), heart rate (HR), and stroke volume (SV) (impedance cardiography) were assessed after supine rest and venous blood was sampled for platelet cGMP (radioimmunoassay on acid extracts of washed platelets), plasma cGMP, atrial natriuretic peptide (ANP), renin activity, aldosterone and platelet aggregation to epinephrine (EPI, 5 micromol/l), and adenosine diphosphate (ADP) (4 micromol/l) (optical aggregometry on platelet-rich plasma (PRP)). Platelet cGMP (7.0 +/- 0.3 pmol/10(9) cells, mean +/- s.e.m.) was lower in males and smokers than in their counterparts (P < 0.01 for both). Among the variables tested, platelet cGMP was related to number of cigarettes (-0.21), high-density lipoprotein cholesterol (HDLc) (r = 0.32), aldosterone (r = -0.21), and hemoglobin (-0.16); in a multivariate analysis that also included sex, HDLc was the best predictor of platelet cGMP. The aggregating response to EPI (r = -0.28), but not to ADP (r = -0.07, ns), was inversely related to platelet cGMP levels. cGMP in resting platelets of EHs is positively predicted by HDLc and is inversely related to the aggregating response to EPI. It is suggested that a defect of the platelet NO/cGMP system could identify uncomplicated EHs at higher risk of thrombotic events during surges of sympathetic activity.

Oral contraceptive pills and inherited thrombophilia in a young woman with deep venous thrombosis

Inherited risk factors for vascular disease include factor V Leiden prothrombin and methylenetetrahydrofolate reductase (MTHFR) point mutations. The use of oral contraceptives is also a recognized risk factor for venous thromboembolism. In Eastern Mediterranean countries the highest frequency of factor V Leiden was reported in Lebanon (14%). However there are no studies related to awareness of the use of oral contraceptive pills among individuals with a high risk for thrombotic events. Here we present the case of a female patient on oral contraceptive pills who sustained an extensive deep venous thrombosis (DVT). The patient was found to be heterozygous for factor V Leiden (G1691A) and homozygous for the MTHFR (C677T) mutations. (excerpt)

The incidence of heparin-induced thrombocytopenia Type II in patients with subarachnoid hemorrhage treated with heparin versus enoxaparin

Heparin-induced thrombocytopenia Type II (HIT II) is a serious complication that occurs in 0.2-3% of patients treated with heparin and is associated with a high risk of thrombotic events. One center recently reported an incidence of HIT II of 15% in a population of patients with aneurysmal subarachnoid hemorrhage (aSAH). Because these patients are typically exposed to heparin during angiography, controversy exists regarding whether prophylaxis with enoxaparin rather than heparin affords any reduction in the risk of developing HIT II. In this study, the authors investigated the effect of heparin compared with enoxaparin on the incidence of HIT II in patients with aSAH. The authors reviewed the medical records of 300 patients treated for aSAH who received thromboprophylaxis with either heparin or enoxaparin, and identified patients who developed HIT II. The incidences of HIT II in the 2 treatment groups were then compared. One hundred sixty-six patients with aSAH were treated with heparin, and 134 patients were treated with enoxaparin. Sixteen (5.3%) of 300 patients met the diagnostic criteria for HIT II. Of those treated with heparin, 8 (4.8%) of 166 developed HIT II, compared with 8 (6%) of 134 treated with enoxaparin (difference not significant). The authors report a lower incidence of HIT II in patients with aSAH than has previously been reported. The data also suggest that patients with aSAH who receive heparin are at no greater risk of developing HIT II than those who receive enoxaparin. This finding challenges the merit of choosing enoxaparin rather than heparin for thromboprophylaxis in patients with a SAH.

Coagulation and Fibrinolysis are in Balance After Moderate Exercise in Middle-aged Participants

Increased age is associated with a higher risk of thrombotic events. The aim of this study was to investigate the age-related changes in hemostasis before and after moderate exercise controlled by individual anaerobic threshold as recommended for rehabilitation training. In this study, 24 young (25 +/- 1 years) and 24 middle-aged healthy nonsmokers (48 +/- 1 years) underwent an individualized exercise test with 80% of individual anaerobic threshold (young individuals: 127 +/- 6 W; middle-aged individuals: 128 +/- 5 W; values are expressed as mean +/- standard error of mean) for 60 minutes. The blood samples were collected before and after the exercise. The age-related higher (P < or = .05) levels could be detected in factors II, VII, VIII, IX, XI, XII, prothrombin fragment 1+2, in tissue plasminogen activator antigen and activity, as well as in plasminogen. The relative exercise-induced increases in these parameters were similar in both groups, although beginning at a higher level for those in the middle-aged group.A statistically enhanced increase after exercise in the middle-aged group could be shown in prothrombin fragment 1+2 (young individuals: 98 +/- 6 to 102 +/- 6 pmol/L; middle-aged individuals: 138 +/- 7 to 156 +/- 8 pmol/L) and in thrombin-antithrombin complex (young individuals: 2.2 +/- 0.1 to 3.1 +/- 0.2 microg/L; middle-aged individuals: 2.4 +/- 0.3 to 3.9 +/- 0.6 microg/L); the latter only showing a tendency. The data show the age-related changes with a rise in blood coagulation and fibrinolysis in a healthy middle-aged group compared with younger participants. Moderate exercise leads to comparably relative increases in hemostatic parameters but starting at higher levels. However, the exercise-induced thrombin generation (prothrombin fragment 1+2) is enhanced in the middle-aged participants in comparison with younger participants, but may be compensated by a sufficient fibrinolysis, and therefore the hemostatic system remains in balance.