Influence of GGCX genotype on warfarin dose requirements in Chinese patients

Introduction

It has been widely accepted that genetic factors were the major sources of the variation in warfarin dose. This study is intended to investigate whether the 3261G>A variation in GGCX gene influences stable warfarin dose in Chinese patient population.

Materials and Methods

A total of 217 patients with stable warfarin dose were enrolled. Genomic DNA was extracted from each subject and the genotype of GGCX 3261G>A was determined by using of denaturing high-performance liquid chromatography (DHPLC). Least significant difference tests (LSDs) were used to compare dose with genotypes. Analysis of variance (ANVOA) was used to calculate the proportion of warfarin dose that could be explained by variation in genotype.

Results

In the total of 217 subjects, 84 patients (38.7%) were GG homozygote, whereas 117 (53.9%) were GA heterozygote and 16 (7.4%) were AA homozygote. Patients with the GGCX 3261AA genotype had a significantly higher average daily maintenance dose (3.39 ± 1.40 mg) than those with the GG genotype (2.69 ± 1.07 mg; P = 0.027), and GGCX 3261G>A explains 2.3% of the univariate warfarin dose variance.

Conclusion

GGCX 3261G>A may affect warfarin dose requirements, and showed a small but significant effect on warfarin dose in a Chinese patient population.     

Endogenous thrombin potential (ETP) in plasma from patients with AMI during antithrombotic treatment

Background

The beneficial impact of warfarin in preventing new events after AMI is well established. Decrease in thrombin generation seems to be the key element in anticoagulant treatment.

Objectives

The aims were to investigate the effect of warfarin and platelet inhibition on thrombin generation, assessed by the endogenous thrombin potential (ETP), and study the relation between coagulation parameters and ETP in patients with AMI.

Patients/Methods

In the present sub-study of the WARIS II trial, patients with AMI were randomly assigned to treatment with aspirin 160 mg/d (n = 57), aspirin 75 mg/d and warfarin (INR 2.0-2.5) (n = 68) or warfarin (INR 2.8-4.2) (n = 61). Fasting blood samples were collected from patients at discharge from hospital and after 6 weeks treatment.

Results

Correlation analyses showed that both ETP and peak thrombin levels were significantly correlated with Factor VII Ag (r = 0.38 and 0.36 respectively, p < 0.01 for both) and with F1+2 (r = 0.26 and 0.23 respectively, p = 0.01 for both) at baseline. Antithrombotic treatment for 6 weeks caused a highly significant inhibition of ETP in patients treated with warfarin (− 28% ± 5%, p < 0.001), and patients treated with aspirin/warfarin (− 24% ± 8%, p = 0.04). Similarly, peak thrombin levels were reduced in patients treated with warfarin (− 18% ± 7%, p = 0.049) and aspirin/warfarin (− 19% ± 5%, p = 0.029), whereas an increase (12% ± 4%, p = 0.029) occurred during aspirin treatment alone. F1+2 levels decreased by 64% and 58% in the warfarin and aspirin/warfarin groups, respectively (p = 0.001 for both).

Conclusions

In patients with AMI, warfarin significantly reduced the endogenous thrombin generation and the potential to generate thrombin in plasma ex vivo, whereas aspirin alone had no effect on thrombin generation in vivo or ex vivo, assessed by ETP.     

Relationship between aspirin and clopidogrel responses in acute coronary syndrome and clinical predictors of non response

Objectives

We have prospectively investigated the association between aspirin and clopidogrel responses and the clinical predictors of non response.

Methods

635 Non ST Elevation Acute Coronary Syndrome (NSTE ACS) patients were included and received loading doses of 250 mg aspirin and 600 mg clopidogrel. We analyzed post-treatment maximal intensity of arachidonic acid and ADP-induced platelet aggregation (AA-Ag and ADP-Ag) and Platelet Reactivity Index of VAsodilator-Stimulated Phosphoprotein (PRI VASP). Aspirin and clopidogrel non responses were defined respectively by AA-Ag > 30% and ADP-Ag > 70%.

Results

Aspirin non responders patients had significantly higher ADP-Ag and PRI VASP than aspirin responders: 63.7 ± 15.9% vs 55 ± 19% (p = 0.0001) and 73.6 ± 13.3% vs 53 ±23% (p = 0.0001) respectively and the rate of clopidogrel non responders was higher among aspirin non responders than aspirin responders: 36.7% vs 22.7% (p = 0.003). In addition, clopidogrel non responders had significantly higher AA-Ag and rate of aspirin non responders than clopidogrel responders: 21.6 ± 24% vs 10.3 ± 19% (p = 0.0001) and 22.8% vs 12.9% (p = 0.003) respectively. Age and Body Mass Index (BMI) were significantly associated with non response to Clopidogrel (p = 0.035 and 0.02 respectively) and diabetes mellitus by trend (p = 0.07).

Conclusion

We observed a relationship between aspirin and clopidogrel non responses and an association between age, BMI and diabetes mellitus and clopidogrel response.     

Effect of VKORC1 - 1639 G > A polymorphism, body weight, age, and serum albumin alterations on warfarin response in Japanese patients

Introduction

To establish individualized warfarin therapy, we investigated the contribution of genetic variations of vitamin K epoxide reductase complex subunit 1 gene (VKORC1) - 1639 G > A and Cytochrome P450 2C9 gene (CYP2C9) and clinical factors on warfarin sensitivity in Japanese patients.

Materials and Methods

Genetic analyses of VKORC1 - 1639 G > A and CYP2C9 ?2, ?3, and ?4 were performed in 259 Japanese patients and 341 healthy subjects. We selected 259 patients who have been prescribed warfarin with a 1.5-3.0 range of prothrombin time normalized as an international normalized ratio for at least 3 months and investigated factors that contribute to individual variability in warfarin dose. Furthermore, multivariate analysis was performed to investigate a warfarin dosing algorithm.

Results and Conclusions

There were great inter-individual differences in warfarin maintenance dose in 259 patients, ranging from a minimum dose of 0.75 mg/day to a maximal dose of 8.00 mg/day. VKORC1 - 1639 G > A polymorphism, body weight, age, and serum albumin were found to affect the inter-individual variability. The dosing algorithm of warfarin maintenance dose was investigated by multivariate linear regression. The regression equation was able to account for 33.2% (R²_Adj = 0.332) of the overall variability in warfarin dose.     

Detection of endogenous tissue factor levels in plasma using the calibrated automated thrombogram assay

Background

The calibrated automated thrombogram (CAT) assay measures thrombin generation in plasma.

Objective

Use the CAT assay to detect endogenous tissue factor (TF) in recalcified platelet-rich plasma (PRP) and platelet-free plasma (PFP).

Methods

Blood from healthy volunteers was collected into citrate and incubated at 37 °C with or without lipopolysaccharide (LPS) for 5 hours. PRP and PFP were prepared and clotting was initiated by recalcification. Thrombin generation was measured using the CAT assay.

Results

The lag time (LT) was significantly shortened in PRP prepared from LPS-treated blood compared with untreated blood (10 ± 3 min versus 20 ± 6 min), and this change was reversed by the addition of inactivated human factor VIIa. LPS stimulation did not change the peak thrombin. Similar results were observed in PFP (21 ± 4 min versus 35 ± 5 min). LPS stimulation also significantly reduced the LT of PRP and PFP derived from blood containing citrate and a factor XIIa inhibitor. Finally, a low concentration of exogenous TF shortened the LT of PFP prepared from unstimulated, citrated blood without affecting the peak thrombin.

Conclusion

Changes in LT in the CAT assay can be used to monitor levels of endogenous TF in citrated plasma.     

Thrombogenic potential of whole blood is higher in patients with acute coronary syndrome than in patients with stable coronary diseases

Introduction

Although thrombogenic potential of blood may play an important role for the onset of acute coronary syndrome (ACS), there is no established way to evaluate it by single parameter. We compared the thrombogenic potential of whole blood between patients with ACS and those with stable coronary diseases using single comprehensive parameter.

Materials and Methods

Consecutive patients with ACS (n = 146) and those with stable coronary heart diseases (control, n = 92) were prospectively examined. Thrombogenic potential of whole blood was evaluated by blood vulnerability index measured by Micro-Channel Array Flow Analyzer (MC-FAN).

Results

Blood vulnerability index was higher in ACS than in control patients (5099 ± 2278 vs. 2071 ± 389, p < 0.0001), higher in acute MI than in unstable angina patients (5693 ± 2146 vs. 3524 ± 1841, p < 0.0001), and higher in ACS patients with initial TIMI 0/1 flow grade than in those with TIMI 2/3 flow grade (6061 ± 1936 vs. 2560 ± 1301, p < 0.0001). Furthermore, blood vulnerability index decreased from acute to chronic stage in acute MI patients. Multivariate logistic regression analysis revealed that high blood vulnerability index, high LDL cholesterol, high CRP, no use of aspirin, and no use of β-blocker were the independent contributors for the onset of ACS.

Conclusion

High thrombogenic potential of whole blood evaluated by blood vulnerability index was significantly associated with ACS and was reduced from acute to chronic stage in acute MI.

Condensed Abstract

Thrombogenic potential of whole blood was evaluated by blood vulnerability index measured comprehensively by Micro-Channel Array Flow Analyzer (MC-FAN) in consecutive patients with ACS (n = 146) or stable coronary diseases (control, n = 92) prospectively. Blood vulnerability index was significantly higher in ACS patients, especially in acute MI and poor initial TIMI flow grade patients, compared with control patients; and blood vulnerability index was reduced from acute to chronic stage in acute MI patients.     

Fibrinogen and D-dimer analysis of chronic subdural hematomas and computed tomography findings: a prospective study

Objective

We investigated the relationship between fibrinolytic factors and computed tomography (CT) findings in patients with chronic subdural hematomas (CSDHs).

Methods

Thirty-one patients with CSDHs were divided on the basis of CT findings into heterogeneous and homogeneous groups. A sample from the subdural hematoma was obtained at surgery to measure the concentrations of fibrinogen and D-dimer.

Results

The mean level of fibrinogen in the heterogeneous group, including the layering (n = 4) and mixed (n = 10) type, was 88.2 ± 121.2 mg/dL, whereas in the homogeneous group, including high density (n = 2), isodensity (n = 9), and low density (n = 6) types, it was <25 mg/dL. The concentration of fibrinogen was significantly higher in the heterogeneous group than in the homogeneous group (p = 0.006). The mean level of D-dimer in the heterogeneous group was 35,407.9 ± 16,325.5 μg/L, whereas for the homogeneous group it was 1476.4 ± 2091.4 μg/L. The concentration of D-dimer was significantly higher in the heterogeneous group than in the homogeneous group (p < 0.001).

Conclusions

The layering and mixed types of CSDH exhibited higher concentrations of fibrinogen and D-dimer in subdural hematoma than the homogeneous types. These fibrinolytic factors appear to be associated with evolution in CSDHs with heterogeneous density.     

Platelet activation in patients with peripheral vascular disease: reproducibility and comparability of platelet markers

Background

Many markers of platelet activation have been described but their reproducibility and comparability in patient populations are poorly defined.

Objectives

We sought to compare markers of platelet and monocyte activation with platelet-monocyte aggregates, a proposed gold standard of in vivo platelet activation, and assess their reproducibility in patients with peripheral arterial disease: a population with substantial platelet activation, inflammation and risk of thrombotic events.

Patients/Methods

Thirty patients with peripheral vascular disease attended on two occasions to permit within-day and between-day comparisons. In vivo platelet and monocyte activation were determined by flow-cytometric quantification of platelet-monocyte aggregation, platelet surface expression of P-selectin and CD40L, platelet-derived microparticles, and monocyte surface expression of CD40 and CD11b. Plasma concentrations of platelet-derived microparticles, soluble P-selectin and CD40L were measured by enzyme-linked immunosorbant assays.

Results

Platelet-monocyte aggregation (36.7 ± 7.86%), and platelet surface expression of P-selectin (5.8 ± 1.65%) and CD40L (3.3 ± 1.45%) demonstrated comparable within-day (mean difference ± co-efficient of reproducibility; 0.9 ± 15.4%, 0.21 ± 1.65% and 0.2 ± 2.8% respectively) and between-day reproducibility (2.0 ± 12.4%, 0.10 ± 2.25% and 0.9 ± 6.4% respectively). Platelet-monocyte aggregates correlated well with other platelet (r = 0.30-0.50, P < 0.02) and monocyte (r = 0.27-0.47, P < 0.03) activation markers. Flow cytometric and assay quantified platelet-derived microparticles showed poorer reproducibility (co-efficient of reproducibility > 40).

Conclusions

In patients with peripheral arterial disease, measurements of platelet-monocyte aggregates have good reproducibility and consistently reflect other markers of platelet and monocyte activation.     

Behavioral and psychological symptoms of dementia in a pilot psychogeriatric unit: management and outcomes

Background

Behavioral and psychological symptoms in dementia (BPSD) are a major concern. The French government gave a consensual definition of reinforced intermediate-term care units for BPSD within the project “Plan Alzheimer 2008/2012”.

Objective

Our aim was to report one of the first experiences of this unit in France.

Results

Fifty-two patients (38 females, 14 males) were included, mean age 82.07 ± 7.84 (73-97). About 80% of patients were improved and there was a high discharge rate to home of about 30%. Night-time behaviors, aberrant motor behaviors and agitation were the most frequent symptoms.

Conclusion

Our study confirms that demented elderly patients greatly benefit from a specific BPSD care unit in agreement with the objective of Plan Alzheimer 2008/2012.     

Comparative performance of warfarin pharmacogenetic algorithms in Chinese patients

Introduction

Multiple warfarin pharmacogenetic algorithms have been confirmed to predict warfarin dose more accurately than clinical algorithm or the fixed-dose approach. However, their performance has never been objectively evaluated in patients under low intensity warfarin anticoagulation, which is optimal for prevention of thromboembolism in Asian patients.

Material and methods

We sought to compare the performances of 8 eligible pharmacogenetic algorithms in a cohort of Chinese patients (n = 282) under low intensity warfarin anticoagulation with target international normalized ratio (INR) ranged from 1.6 to 2.5. The performance of each algorithm was evaluated by calculating the percentage of patients whose predicted dose fell within 20% of their actual therapeutic dose (percentage within 20%), and the mean absolute error (MAE) between each predicted dose and actual stable dose.

Results

In the entire cohort, the pharmacogenetic algorithms could predict warfarin dose with the average MAE of 0.87 ± 0.17 mg/day (0.73-1.17 mg/day), and the average percentage within 20% of 43.8% ± 8.1% (29.1% - 52.1%). By pairwise comparison, warfarin dose prediction was significantly more accurate with the algorithms derived from Asian patients (48.6% - 50.0%) than those from Caucasian patients (29.1% - 39.7%; odds ratio [OR]: 1.61-3.36, p ≤ 0.02). Algorithms with additional covariates of INR values or CYP4F2*3 performed better than those without the covariates (adding INR: OR: 1.71 (1.08-2.72), p = 0.029; adding CYP4F2*3: OR: 2.67(1.41-5.05), p = 0.004). When the patients were stratified according to the dose range, the algorithms from Caucasian and racially mixed populations tended to perform better in higher dose group (≥ 4.5 mg/day), and algorithms from Asian populations performed better in intermediate dose group (1.5-4.5 mg/day). None of the algorithms performed well in lower dose group (≤ 1.5 mg/day).

Conclusions

No eligible pharmacogenetic algorithm could perform the best for all dosing range in the Chinese patients under low intensity warfarin anticoagulation. Construction of a refinement pharmacogenetic algorithm integrating 3 genotypes (CYP2C9, VKORC1 and CYP4F2) and INR data should be warranted to improve the warfarin dose prediction in such patients.     

The risk of false results in the assessment of platelet function in the absence of antiplatelet medication: Comparision of the PFA-100, multiplate electrical impedance aggregometry and verify now assays

Objectives

Evaluation of aspirin (ASA) responsiveness with platelet function tests varies by the choice of blood mixture and functional test and cut off values for defining the the treatment used. Addition to that we also aimed to determine aggregement between three tests and to research whether there is any necessity to measure baseline platelet activity.

Methods

The study group comprised of 52 patients with multiple risk factors receiving primary prophylaxis of ASA (100 mg/day). For each patient inhibition of platelet aggregation with aspirin was determined using three different whole blood tests: Multiplate electrical impedance aggregometry , Verify Now Aspirin, and collagen-epinephrine closure time PFA-100. Platelet aggregation was assessed with multiplate electrical impedance aggregometry,and was defined as the area under curve (AUC,AUxmin).Maximal 6,4 microM collagen-induced AUC were used to quantify platelet aggregation due to ASA.The ASA response was defined as > 30 % reduction in basal platelet aggregation with multiplate electrical impedance aggregometry.Collagen induced platelet aggregation at the Verify Now Aspirin assay quantitated the ASA-induced platelet inhibition as aspirin reaction units (ARU).According to manifacturer insert ARU > 550 indicates aspirin resistance. ASA platelet function studies were assessed twice at baseline (pre-aspirin), and after 7 day(post-aspirin) were performed.

Results

After ASA intake none of the patients was found aspirin resistant with PFA-100. (CEPI-CT (129 ± 36 vs 289 ± 18 ). None of the patients was found aspirin resistant with PFA-100. As > 30 % reduction in bazal platelet aggregation with multiplate electrical impedance aggregometry is selected all of the patients have been stratified as responders.(COL TEST 688±230 vs 169 ± 131 AU) None of the patients with Verify Now Aspirin found resistance to ASA(594 ± 62 vs 446 ± 43).Prior to ASA intake 15 of all patients with VN(501 ± 16) and 2 of all patients with multiplate electrical impedance aggregometry (223 ± 40 AUC )aggregation levels below the cut off label before ingestion of ASA.None of the patients was above the cut off label with PFA -100 (129 ± 36).

Conclusions

Verify Now ASA assay, multiplate electrical impedance aggregometry and PFA-100 seem to be reliable tests in reflecting ASA effect on platelets. Cut off labels for the defining the responsiveness given by man?facturer may show significant interindividual variabiliy with Verify Now ASA assay and multiplate electrical impedance aggregometry, and these test may show platelet inhibition despite the absence of ASA intake. Consideration of the pretreatment values may eliminate the risk of overestimation in the assessment of platelet inhibtion by ASA.     

Circulating activated factor XI and active tissue factor as predictors of worse prognosis in patients following ischemic cerebrovascular events

Background

Elevated factor (F)XI is associated with an increased risk for ischemic stroke. Activated FXI (FXIa) and tissue factor (TF) have not been studied following stroke. The aim of the current study was to evaluate circulating FXIa and TF in patients with prior cerebrovascular events.

Patients/Methods

We studied 241 patients, including 162 after ischemic stroke and 79 after transient ischemic attack (TIA), recruited 6 months to 4 years (median, 36 months) after the events. Plasma TF and FXIa activity following the index event were determined in clotting assays by measuring the response to inhibitory monoclonal antibodies.

Results

Active TF was detected in 25 (10.4%) of the patients, while FXIa activity (median, 37.5 [IQR 397] pM) was found in 64 (26.7%) of the patients (p < 0.01). The prevalence of active TF and FXIa was higher in subjects with previous stroke compared with those with a history of TIA (13% vs 5.1%, p = 0.05, and 34% vs 11.4%, p < 0.0001, respectively). Patients with circulating FXIa were younger and had higher fibrinogen and interleukin-6 compared to the remainder. Patients with detectable TF or FXIa activity had higher NIHSS score, higher modified Rankin scale and lower Barthel Index than the remaining subjects (all p < 0.05).

Conclusion

Circulating active TF and FXIa can occur in patients with cerebrovascular ischemic events ≥ 6 months after the events. The presence of these factors is associated with worse functional outcomes, which highlights the role of persistent hypercoagulable state in cerebrovascular disease.     

EMPoWarMENT: Edmonton Pediatric Warfarin Self-Management Pilot Study in Children with Primarily Cardiac Disease

Increasing numbers of children require warfarin thromboprophylaxis. Home INR testing by the patient (PST) has revolutionized warfarin management. However, the family/patient must contact the health team for guidance for warfarin dosing. Patient self management(PSM) prepares a patient performing PST to take an active role in warfarin dosing. Adult studies demonstrate that PSM is safe and effective with improved adherence and treatment satisfaction quality of life (QOL).

Objective

To estimate the safety and efficacy in children performing PSM or PST, to evaluate warfarin dose decision making in PSM, and warfarin related QOL.

Methods

Warfarinized children performing PST for > 3 m were randomized to PST or PSM. The PSM group underwent warfarin management education and assumed independent warfarin management. INRs were collected for a year prior to and for 1 year of study to determine TTR and warfarin decision making. QOL was assessed through inventory completion and interviews.

Results

28 children were randomized and followed for 12 months. TTR was (83.9% pre/ post), and 77.7% pre to 83.0% post for PST and PSM (p = 0.312). Appropriate warfarin decision making was 90% with no major bleeding episodes and no thromboembolic events. PSM was preferred by families. Conclusions: PSM for children may be a safe and effective management strategy for warfarinized children. Clinical studies with larger sample size are required.     

Effect of increased aspirin dose after stenting in association with ClOpidogrel: the FIASCO randomized study

Background

Increased doses of antiplatelet therapy have been proposed to overcome the variability of response. However, the chronic dose of aspirin after DES remains controversial.

Methods and results

We assessed in a prospective and randomized study the benefit of higher dose of aspirin, in association with clopidogrel, on aspirin response and non COX-specific platelet testing in patients receiving Drug Eluting Stent (DES) for stable angina pectoris. 50 consecutive patients receiving DES for stable angina pectoris were prospectively included. They received loading dose of 250 mg aspirin and 600 mg clopidogrel and antiplatelet response was assessed with Arachidonic Acid-induced aggregation (AA-Ag) and ADP-induced aggregation (ADP-Ag) for aspirin and clopidogrel response respectively. Patients were randomized to either 75 or 160 mg of aspirin with 150 mg clopidogrel and platelet testing were repeated one month after hospital discharge. The two groups (aspirin “75 mg” or “160 mg”) had no difference for aspirin response: AA-Ag (5.2 ± 1.7% vs 6 ± 2%, p = 0.75) and non COX-specific pathway testing: ADP-Ag (47 ± 3% vs 49 ± 4%, p = 0.61).

Conclusion

The present study did not show any benefit of higher dose of aspirin neither on aspirin responsiveness, nor on inhibition of non COX-specific pathway. These data does not support use of higher dose than 75 mg of aspirin in association with clopidogrel in patients receiving DES, especially while higher doses have been associated with increased bleeding risk.     

Platelet glycoprotein VI (GPVI) for early identification of acute coronary syndrome in patients with chest pain

Background

Platelet glycoprotein VI (GPVI) is elevated in patients with acute coronary syndrome (ACS), stroke and associated with acute coronary events. GPVI may be helpful to distinguish an imminent ACS from non-coronary (NC) causes in patients with chest pain who were transferred to chest pain unit, before the myocardial necrosis is evident with classical biomarkers.

Methods

Based on the findings of our previous studies, we consecutively examined 1004 patients with chest pain in a prospective study design. ACS was found in 416 (41.4%), stable angina pectoris (SAP) in 233 (23.2%), and NC causes of chest pain (hypertension, musculoskeletal disease, pulmonary embolism, myocarditis, cardiophobia) in 355 patients (35.4%). Platelet surface expression of GPVI was measured by flow cytometry.

Results

Patients with ACS showed significantly enhanced GPVI expression levels compared to patients with SAP or NC causes of chest pain (ACSvs.SAP(mean fluorescence intensity (MFI) ± SD):18.9 ± 7.4vs.17.9 ± 9.5;P = 0.028;ACSvs.NC:15.4 ± 6.9;P = 0.002). Elevated GPVI expression was associated with ACS independent of markers of myocardial necrosis like troponin and creatine kinase-MB. Patients with an elevated GPVI expression (MFI ≥ 18.6) had a poorer clinical outcome than patients with baseline GPVI expression in regard to composite cumulative survival that included myocardial infarction, stroke, and cardiovascular death at three months (Log rank;P = 0.025).

Discussion

Platelet GPVI surface expression is enhanced in patients at risk for an ACS and is an early marker for imminent acute coronary events in patients with chest pain.     

Pioglitazone inhibits platelet function and potentiates the effects of aspirin: a prospective observation study

Background

Thiazolidinediones (TZDs) are agonists of PPARγ and exert beneficial metabolic effects in patients with diabetes. They may also affect platelet function.

Objectives

To characterize potential platelet inhibitory effect of pioglitazone alone and in the presence of aspirin.

Methods

20 normal and 20 diabetic subjects were enrolled in a prospective study. On day 1, a blood sample was obtained at baseline and a second one after ingestion of 30 mg of pioglitazone. PRP was prepared and platelet aggregation and release were evaluated using ADP, collagen and arachidonic acid as agonists. Subjects returned at 6-9 days later after ingesting a single 81 mg dose of aspirin and a third blood sample was obtained. The subjects then again ingested 30 mg of pioglitazone and a fourth and final blood sample was obtained. Platelet aggregation and release were measured. PRP was incubated with thrombin to activate platelets, and the serum was separated and assayed for thromboxane B2, TGFβ and CD40L

Results

Pioglitazone alone did not affect aggregation with arachidonic acid. However, following ingestion of both aspirin and pioglitazone aggregation was significantly decreased compared to aspirin alone (P < 0.0001). Pioglitazone also potentiated aspirin-induced inhibition of ATP release using either arachidonic acid or collagen. Following pioglitazone alone, TXB₂ release was 32,719 ± 3,585 pg/ml which was significantly reduced compared to baseline (42,075 ± 4,479, P = 0.0004). Pioglitazone also potentiated the inhibition of TXB₂ release by aspirin.

Conclusion

Pioglitazone inhibits platelet function and potentiates the inhibitory effects of aspirin.     

Risk of bleeding in low-risk atrial fibrillation patients on warfarin waiting for elective cardioversion

Introduction

Systemic embolism is the most serious complication of cardioversion of atrial fibrillation (AF) and the immediate post-cardioversion period is associated with increased risk for thrombus formation. For this reason, treatment with vitamin K antagonist (VKA) is recommended for patients with AF. No information is available about bleeding risk related to this practice.

Methods

We performed a prospective multicentre study on 242 low-risk AF patients (CHADS₂ score 0-1) that started on warfarin for elective cardioversion to evaluate their bleeding risk.

Results

178 were males (73.6%), mean age 63.9 ± 9.8 years, 60 patients (25%) were aged ≤ 59 years. Patients with CHADS₂ score = 0 were 73 (30%), those with CHADS₂ score = 1 were 169 (70%). Patients were on VKA treatment, maintained at INR intended therapeutic range 2.0-3.0, for a median time of 159 days (range 30-631)total follow-up period 127 patient-years (pt-yrs). Quality of anticoagulation and occurrence of bleeding events were recorded. Patients spent 23%, 64% and 8% of time below, within and above the intended therapeutic range, respectively. When we observed the INR levels, we found that 62 patients (25.6%) had INR > 4.5 at least in one occasion, and 23 (9.5%) in ≥ 2. During follow-up, 2 patients had major bleeds (rate 1.6% pt-yrs), one fatal. No embolic complications were recorded.

Conclusion

Our results show that low-risk AF patients, treated with VKA for elective cardioversion, carry a not irrelevant risk of bleeding. Efforts are required to properly select patients who could benefit from this procedure, reducing the time of warfarin exposure.     

Decreased serum BDNF levels in major depressive patients

Background

Brain-derived neurotrophic factor (BDNF) plays an important role in neuronal plasticity. The aim of the present study was to measure serum BDNF levels in depression and to analyze the relationship between BDNF levels and severity of depression.

Methods

Thirty patients meeting the DSM-IV criteria for major depressive disorder and 40 normal control subjects were recruited for this study. Patients had not used psychotropic drugs. The severity of depression was assessed by the Hamilton Rating of Depression Scale (HAM-D). Serum BDNF levels were determined by using ELISA.

Results

HAM-D scores were 17.09 ± 4.96 in depressed patients. We determined that the serum BDNF levels of the depression patients were lower than those of the healthy control group (respectively, 1453.42 ± 144.51 pg/ml, 1632.23 ± 252.93 pg/ml, t = 3.467, p = 0.001, independent t test). No correlation was found between the patients’ serum BDNF levels and HAM-D scores (p > 0.05, Pearson correlation analysis).

Conclusions

Our results suggest that serum BDNF levels are low in depression. However it was not found association between serum BDNF levels and the severity of depression.     

The effect of clopidogrel besylate and clopidogrel hydrogensulfate on platelet aggregation in patients with coronary artery disease: a retrospective study

Background

Recently several alternative forms of the original clopidogrel hydrogensulfate (CHS) were spread worldwide. A large amount of such drugs turned out to be clopidogrel besylate (CB). Only three studies, involving healthy volunteers, investigated the antiplatelet effect of CB, whereas its attribute remained unexplored in the case of patients with cardiovascular diseases. This retrospective study aimed to evaluate the difference between the antiplatelet effects of two clopidogrel formulas, CHS and CB, on patients with coronary artery diseases.

Methods

Data of 150 patients with previous CHS treatment were investigated. According to the documentations, the CHS therapy was shifted to CB. 94 patients of the selected population received dual antiplatelet therapy, clopidogrel and aspirin. The antiplatelet effects of CHS and CB were compared by ADP induced platelet aggregation measurements using light transmission aggregometry.

Results

Irrespective of the therapeutic combinations the performed statistical investigations failed to show significant difference (p = 0.30) between the effect of CB (AGGmax_CB: 27.6 ± 13.7%) or CHS (AGGmax_CHS: 29.0 ± 15.3%) on the ADP induced platelet aggregation. Insignificant deviations were found in both forms of clopidogrel salts, either in the lack (AGGmax_CB : 32.5 ± 14,2%; AGGmax_CHS: 34,0 ± 16,1%; p = 0,29) or in the presence of aspirin (AGGmax_CB: 24.7 ± 12,5%; AGGmax_CHS: 26,0 ± 14,1%; p = 0,31).

Conclusion

Our results indicated that both CB and CHS had an identical inhibitory effect on ADP induced platelet aggregation in patients with cardiovascular diseases. Moreover their efficiency showed no overall significant difference in the case of dual antiplatelet therapy with aspirin as well. However there might be an inter- and intraindividual variability between the two clopidogrel formulas.