The incidence of pulmonary embolism (PE) after spinal fusions

Background

Pulmonary embolism (PE) is a rare but serious event that may occur after spinal surgery.

Objective

To correlate PE incidence after spinal arthrodesis with surgical approach, region of spine operated, and primary spinal pathology. To identify PE incidence trends in this population.

Methods

The Nationwide Inpatient Sample was queried using ICD-9 codes (81.01–81.08) for spinal fusion procedures over a 21-year period (1988–2008). Other data points included PE occurrence, surgical approach, spinal region, surgical indication, and mortality. Multivariate and relational analyses were performed.

Results

4,505,556 patients were identified and 9530 had PE (incidence = 0.2%). PE patients had higher odds of combined A/P surgical approaches than posterior approaches (OR = 1.97; 95% CI = 1.66–2.33), and PE incidence was higher in thoracic versus cervical or lumbar fusions (OR = 2.54; 95% CI = 2.14–3.02). PE was more likely with vertebral fracture (OR = 1.85; 95% CI = 1.53–2.23) and SCI with vertebral fracture (OR = 4.59; 95% CI = 3.72–5.70) than without trauma. Between 1988 and 2008, the PE incidence remained stable for patients with intervertebral disk degeneration and scoliosis, but increased for patients with vertebral fracture, and SCI with vertebral fracture. There was greater inpatient mortality with occurrence of a PE (OR = 12.92; 95% CI = 10.55–14.41).

Conclusion

Although the incidence of PE in spinal arthrodesis patients is only 0.2%, there is a higher incidence after combined A/P approaches, thoracic procedures, and trauma surgical procedures. Despite the overall PE incidence remaining stable since 1988, incidence steadily increased among trauma patients. Further research is needed to explain these trends, given the context of changing patient populations and improving surgical techniques and prophylaxis measures. Greater caution and prophylaxis among trauma patients may be warranted.     

History of depressive and/or anxiety disorders as a predictor of treatment response: A post hoc analysis of a 12-week, randomized, double-blind, placebo-controlled trial of paroxetine controlled release in patients with fibromyalgia

Background

Despite of a high comorbidity of depressive and/or anxiety disorders with fibromyalgia, information on the clinical implications of this comorbidity is limited but antidepressants are commonly prescribed to treat fibromyalgia in clinical practice. We investigated whether a history of depressive and/or anxiety disorders was associated with response to paroxetine controlled release (CR) in the treatment of fibromyalgia.

Methods

One hundred sixteen (116) fibromyalgia subjects were randomized to receive paroxetine CR or placebo for 12 weeks. The primary outcome was treatment response defined as ≥ 25% reduction in the Fibromyalgia Impact Questionnaire (FIQ) score. In multivariate logistic regression, we determined if a history of depression and/or anxiety disorders was an independent predictor of response to paroxetine CR.

Results

In logistic regression, the history of depression and/or anxiety did not predict treatment response as measured by ≥ 25% reduction in Fibromyalgia Impact Questionnaire (FIQ) score (OR = 0.66, 95% CI = .29–1.49, Wald = 0.97, p = 0.32), while the drug status (paroxetine CR) was significantly associated with treatment response (OR = 2.57, CI = 1.2–5.61, Wald = 5.5, p = 0.02).

Conclusion

A significant proportion of patients with fibromyalgia had a history of anxiety and or depressive disorders. However response to treatment of fibromyalgia symptoms with paroxetine CR was not associated with a history of depressive and/or anxiety disorders. Our findings need to be confirmed in more adequately-powered and well-designed subsequent studies.     

Lipoprotein lipase Ser447Ter polymorphism associated with the risk of ischemic stroke: a meta-analysis

Introduction

Previous studies suggested lipoprotein lipase (LPL) Ser447Ter and Asn291Ser polymorphisms were associated with the risk of ischemic heart disease, however, their effects on ischemic stroke were controversial. A meta-analysis was performed to assess the associations between these two LPL polymorphisms and the risk of ischemic stroke.

Methods

The electronic databases PubMed and Embase were used to identify relevant studies by two interviews independently. The pooled odds ratios (ORs) and weighted mean differences (WMD) with 95% confidence interval (CI) were estimated for the risk of ischemic stroke and the plasma lipids in various Ser447Ter genotypes respectively. A fixed or random effect model was selected for pooling data based on homogeneity test.

Results

13 studies including 4,681 ischemic stroke cases and 8,516 controls were involved in this meta-analysis. Overall, LPL Ter447 variant was associated with a significantly reduced risk for ischemic stroke (OR = 0.79, 95% CI: 0.68-0.93) both in Caucasian (OR = 0.87, 95% CI: 0.77-0.97) and East-Asian (OR = 0.65, 95% CI: 0.43-0.99), whereas no significant association of Ser291 variant was observed (OR = 1.25, 95% CI: 0.96-1.63). The Ser447Ter polymorphism may be more important in association with the decreased risk of atherosclerotic stroke (OR = 0.44, 95% CI: 0.32-0.62) which derived from significantly increased high density lipoprotein cholesterol, decreased triglyceride and total cholesterol in Ter447 carriers compared with non-carriers.

Conclusions

This meta-analysis indicated that LPL Ser447Ter polymorphism was associated with a significant reduction in the risk of ischemic stroke, especially atherosclerotic stroke subtype in both Caucasian and East-Asian.     

Prothrombotic factors and the risk of acute onset non-cardioembolic stroke in young Asian Indians

Introduction

Several prothrombotic factors - both hereditary and acquired - are known to cause stroke. Commonly investigated causes are activated protein C resistance, factor V Leiden mutation, factor VIII levels, prothrombin 20210 G-to-A mutation, coagulation inhibitors such as proteins C and S, and antiphospholipid antibodies such as β₂-glycoprotein.

Objective

The literature on the prevalence of hematological defects pertaining to these variables in the Asian Indian stroke population is limited to a few isolated reports. In the current study we investigate the above-mentioned variables in 120 stroke patients (non-cardioembolic acute-onset stroke) and compare their status with the hematological profile of an equal number of healthy age- and sex-matched controls.

Material and Methods

Plasma and blood leukocytes were collected from all patients and controls for performing hematological assays and molecular tests respectively. The mutations were detected using standard polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) procedures. Statistical analysis was done using SPSS version 12.0.

Results

Factor V Leiden (prevalence 8.3% in patients) and activated protein C resistance (prevalence 19.6% in patients) both showed a high degree of association (P < 0.01) with the disease condition. However, contrary to common expectations, factor V Leiden was observed much less frequently in patients showing activated protein C resistance (10 out of 23; 43.4%) than is commonly observed in the Caucasian population (almost 90%). Post-acute-phase factor VIII levels were also found to be significantly associated with stroke: 125.6 + 21.1% number of profitable positions (NPP) for controls and 136.2 + 28.8% NPP for patients (P = 0.001).

Conclusion

factor V mutations, such as factor V Leiden, may be important risk factors for stroke in an Asian Indian population. Activated protein C resistance has a stronger association with stroke than factor V Leiden and may be caused by other factors such as elevated factor VIII levels in the Asian Indian population apart from factor V Leiden itself.     

Association of the -757T>C polymorphism in the CRP gene with circulating C-reactive protein levels and carotid atherosclerosis

Introduction

C-reactive protein (CRP) is an inflammatory protein that may play a role in the pathogenesis of atherosclerosis. CRP gene single nucleotide polymorphisms (SNPs) have been shown to be associated with CRP concentration; however, their independent effect on atherosclerosis has not been yet established. We aimed to determine whether the 5′-flanking -757T>C CRP gene polymorphism is associated with CRP concentration and carotid atherosclerosis.

Methods

We genotyped the -757T>C CRP gene SNP and determined the concentration of serum CRP, the intima-media thickness (IMT) of the common carotid artery and the existence of plaque/s in 612 apparently healthy men and women aged 66 ± 10 years.

Results

Carriers of the CRP -757C allele presented with higher IMT and higher CRP concentrations (p = 0.002, p = 0.042, respectively). After adjustment for vascular risk factors, linear regression analysis showed an independent effect of CRP -757C allele on carotid IMT, beyond serum CRP concentrations. This SNP was also associated with carotid plaque occurrence (O.R. 1.74, 95% CI 1.1-2.77, p = 0.002).

Conclusions

The present study provides evidence that a genetic variant of CRP gene is associated with carotid atherosclerosis, independently of traditional vascular risk factors. Further large-scale genomic studies are required, which may identify the genetic vulnerable subjects to develop atherosclerosis.     

Peri-procedural anticoagulation management of mechanical prosthetic heart valve patients

Introduction

To estimate the three-month cumulative incidence of thromboembolism and bleeding among mechanical heart valve (MHV) patients receiving peri-procedural anticoagulation management, consecutive MHV patients referred to the Mayo Clinic Thrombophilia Center for peri-procedural anticoagulation management over the seven-year period, 1997-2003, were followed for three months for thromboembolism, bleeding and vital status.

Materials and Methods

Warfarin was stopped 4-5 days prior to the procedure, and re-started after the procedure as soon as hemostasis was assured. The decision to provide bridging therapy with low molecular weight (LMWH) or unfractionated (UFH) heparin was individualized and based on the estimated risks of TE and bleeding.

Results

556 MHV patients (372 aortic only, 136 mitral only, 48 with multiple valves) underwent 580 procedures. The three-month cumulative incidence of thromboembolism was 0.9% which included: cerebral ischemia (n = 3), unstable angina (n = 1), acute myocardial infarction (n = 1). None were fatal. The cumulative incidence of major bleeding was 3.6% and fatal in 0.2%. The incidence of major bleeding events did not differ by postoperative anticoagulant strategy whether LMWH (3.7%), UFH (6.1%), or no heparin (2.4%) was used (p = 0.26).

Conclusions

The three-month cumulative incidence of thromboembolism among MHV patients in whom anticoagulation is temporarily interrupted for an invasive procedure is low. Whereas bleeding exceeds thromboembolic complications, our current practice is to restart warfarin as soon as possible post-procedure. Post-procedural heparin use is reserved for patients with the highest thromboembolic risk (mitral MHV, multiple MHVs, MHV with prior stroke or atrial fibrillation) waiting at least 48 hours before initiating.     

Immobilization and the risk of venous thromboembolism. A meta-analysis on epidemiological studies

Background

The thrombogenic burden of immobilization remains unknown especially in the medical setting. Most of epidemiological studies estimating the link between risk factors and venous thromboembolism (VTE) have not been designed to evaluate immobilization. The aim of this work was to estimate the risk of VTE in medical bedridden patients by a systematic review and a meta-analysis.

Methods

A research on PUBMED and EMBASE was carried out to retrieve case-control and cohort studies showing the proportion of bedridden patients with or without VTE. Included studies were assigned in six groups according to the following criteria: 1) their design (cohort or case-control), 2) the targeted population (with or without suspicion of VTE) and 3) the medical setting (ambulatory or hospital). Odd-Ratios and Relative Risk for case-control and cohort studies were calculated using a random effect method. Heterogeneity and publication bias were statistically assessed by the I² statistics and funnel plots with Egger's tests.

Results

43 studies were included (24181 patients). The pooled RR ranged from 1.46 to 2.77 in the subgroups of cohort studies (n = 36) with an overall RR of 1.86 (1.61-2.14; P < 0.001). The pooled OR were 2.79 and 2.47 in the two subgroups of case-control studies (n = 7), both statistically significant (overall OR: 2.52; 1.70-3.74; P < 0.001). Heterogeneity through studies was demonstrated in four subgroups. Publication bias was only observed in one subgroup.

Conclusions

Among medical patients, immobilization increases the risk of VTE. Nevertheless, a specific role of underlying conditions can not be excluded.     

Lack of association between a functional genetic variant of connexin 37 and ischemic stroke in a Taiwanese population

Introduction

Connexin 37, encoded by the GJA4 gene, protects against atherosclerosis. A recent study reported an association between polymorphism rs1764391 at GJA4 and ischemic stroke in a Chinese population. We aimed to replicate this result.

Materials and Methods

A total of 958 ischemic stroke patients and 2196 controls were enrolled for the study. All participants were Chinese residing in Taiwan. Logistic regression analysis with adjustment for traditional risk factors was used to estimate the genetic effect. We also performed stratification analyses by sex and stroke subtypes. Literature reviews were conducted for available genetic association studies investigating rs1764391 and cardiovascular phenotypes.

Results

We did not find any significant association for overall stroke (p = 0.87) or from any subset analyses. Eight studies addressing the associations between rs1764391 and cardiovascular phenotypes had a sample size greater than 1000. Including the present study, five out of the eight large-scale studies found no association.

Conclusions

GJA4 polymorphism is not associated with stroke risk in the Taiwanese population.     

Lack of evidence for association between factor XIII-A Val34Leu polymorphism and ischemic stroke: A meta-analysis of 8,800 subjects

Introduction

Epidemiological studies have evaluated the association between factor XIII-A (FXIII-A) Val34Leu polymorphism and risk of ischemic stroke, but the results remain inconclusive. This meta-analysis was therefore designed to clarify these controversies.

Methods

Systematic searches of electronic databases Embase, PubMed and Web of Science, as well as hand searching of the references of identified articles and the meeting abstracts were performed. Study selection, data abstraction and study quality evaluation (using the Newcastle-Ottawa Scale, NOS) were independently conducted in duplicate. Statistical analyses were performed using software Review Manager (Version 5.1.2) and Stata (Version 11.0). The pooled odds ratios (ORs) with 95% confidence intervals (95%CIs) were performed. Fixed or random effects model was separately used depending on the heterogeneity between studies. Publication bias was tested by funnel plot, Egger's regression test and Begg's test. Sensitivity analysis was conducted by limiting the meta-analysis to the high quality studies (NOS score≥8).

Results

A total of 16 studies including 3,807 cases and 4,993 controls were combined showing no evidence of association between FXIII-A Val34Leu polymorphism and ischemic stroke (for Val/Leu vs. Val/Val : OR = 0.95, 95%CI = 0.77-1.16; for Leu/Leu vs. Val/Val: OR = 0.90, 95%CI = 0.73-1.11; for dominant model: OR = 0.97, 95%CI = 0.81-1.17; for recessive model: OR = 0.95, 95%CI = 0.77-1.17). In the subgroup analyses by study design, ethnicity and specific subtypes (small-vessel occlusive ischemic stroke and large-artery atherosclerotic ischemic stroke ), there was lack of evidence for the association.

Conclusions

This meta-analysis indicates that there is no evidence for association between factor XIII-A Val34Leu polymorphism and ischemic stroke.     

Outcome of Chlamydia pneumoniae associated acute ischemic stroke in elderly patients: a case-control study

Background

Limited data exists about the role of Chlamydia pneumoniae elderly patients with acute ischemic stroke.

Objective

To study the role of C. pneumoniae in elderly patients (age more than 65 years) with acute ischemic stroke and its impact on stroke out come.

Methods

We recruited 100 elderly patients with acute ischemic stroke and 100 age and sex matched controls over a period of 2 years. IgG and IgA anti C. pneumoniae antibodies were measured by microimmunofluorescence technique in patients and controls. Good outcome was defined as a Modified Rankin score (mRS) of ≤2.

Results

We found C. pneumoniae antibodies in 35% stroke patients and in 18% control subjects (p = 0.01). Good out come at 90 days follow up was found in 20/35(57.1%) seropositive stroke patients compared to 37/65(56.9%) seronegative stroke patients (p = 0.9).

Conclusions

C. pneumoniae antibody positivity was independently associated with ischemic stroke in elderly patients and its presence does not alter the stroke outcome.     

No evidence for an association between ABO blood group and overall ischemic stroke or any of the major etiologic subtypes

Introduction

The ABO blood group system is encoded by one gene, ABO. Previous studies have reported an association between blood group non-O (i.e. phenotype A, B or AB) and myocardial infarction. Studies on stroke and ABO are, however, more scarce. Therefore, we aimed to investigate whether ABO phenotype or genotype is associated with ischemic stroke and/or etiologic subtypes of ischemic stroke.

Materials and methods

The study was performed in the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS), which comprises 600 patients with ischemic stroke before the age of 70 years, and 600 matched controls. Patients were classified according to the TOAST criteria.

Results

There was no significant association between ABO phenotype (blood group O vs. non-O) and overall ischemic stroke (multivariable odds ratio of 0.9, 95% confidence interval 0.7-1.2). This was also true for blood group O vs. A and O vs. B. Furthermore, no association between ABO genotypes and ischemic stroke was detected. The ischemic stroke subtype analysis was confined to large-vessel disease, small-vessel disease, cardioembolic stroke and cryptogenic stroke. In this analysis, there was no significant association between any ischemic stroke subtype and ABO phenotype or genotype.

Conclusions

The findings in this study suggest that ABO phenotype or genotype does not have a major impact in the pathophysiology of ischemic stroke or any of the ischemic stroke subtypes.     

Smoking promotes clopidogrel-mediated platelet inhibition in patients receiving dual antiplatelet therapy

Background

High on-treatment residual platelet reactivity is associated with an increased risk of adverse events after coronary stenting. Recent data suggest that cigarette smoking might enhance clopidogrel-mediated platelet inhibition. We therefore sought to investigate the influence of cigarette smoking on clopidogrel- and aspirin-mediated platelet inhibition after percutaneous intervention with stent implantation.

Patients and methods

Platelet aggregation was assessed by the VerifyNow P2Y12 and aspirin assays in 102 patients on dual antiplatelet therapy 24 hours after peripheral, coronary or carotid artery stenting. Among these, there were 33 nonsmokers, 29 former smokers and 40 current smokers. Patients in the fourth quartile of the VerifyNow assays were considered as patients with high on-treatment platelet reactivity.

Results

Current smokers had significantly lower P2Y12 Reaction Units compared with nonsmokers (p = 0.028). Former smokers also had lower adenosine diphosphate (ADP)-inducible platelet aggregation than nonsmokers, but the difference was not significant (p = 0.52). A high on-treatment residual ADP-inducible platelet aggregation was more common among nonsmokers than among current smokers (14 vs 5; p = 0.004). In a multivariate regression analysis smoking was an independent influencing variable for post-treatment ADP-inducible platelet reactivity (p = 0.026). Aspirin-mediated platelet inhibition showed no significant differences between nonsmokers and former smokers or current smokers (p > 0.3).

Conclusion

By in vitro testing, cigarette smoking is associated with enhanced clopidogrel- but not aspirin-mediated platelet inhibition. The clinical implications have to be evaluated in large prospective trials.     

The rs11833579 and rs12425791 polymorphisms and risk of ischemic stroke in an Asian population: A meta-analysis

Background

In 2009, a GWAS has confirmed that rs11833579 and rs12425791 near the NINJ2 gene could increase the stroke and ischemic stroke (IS) risk. Recently, several studies have been implemented to assess the relationship between the two SNPs and ischemic stroke risk in Asian. However, the results were poorly consistent. To study the association between the both polymorphisms and the risk of ischemic stroke, we performed a meta-analysis.

Methods

We used odds ratios (ORs) with 95% confidence intervals (CIs) to evaluate the strength of association. The heterogeneity was checked by Q test and the inconsistency index (I²). Begg's test and Egger's test were used to assess the possible publication bias.

Results

Our study included 6 articles, contained 9 independent case-control studies, involved a total of 9,142 cases and 10,652 controls about rs11833579, 10,165 cases and 11,592 controls about rs12425791. There was a significant association between rs12425791 and IS risk with dominant genetic model (OR = 1.087, 95%CI = 1.021-1.158, I² = 34.6%, P = 0.152), but not with recessive genetic model and allele A vs. allele G. For rs11833579, we failed to verify it relate with IS risk under allele A vs. allele G, dominant and recessive genetic model.

Conclusions

This meta-analysis suggest that rs12425791 is relative to ischemic stroke risk under dominant model in Asian population, but not for rs11833579.     

Chronic oral anticoagulant therapy in carotid artery stenting: the un-necessity of perioperative bridging heparin therapy

Introduction

Chronic oral anticoagulant therapy (OAT) is of widespread use, and usually its management in patients undergoing carotid artery stenting (CAS) is through perioperative bridging heparin therapy. Aim of the present study is to analyze a single center experience of CAS in patients maintaining OAT without perioperative bridging heparin therapy.

Materials and methods

A retrospective evaluation of consecutive patients submitted to CAS was performed. Clinical anatomical characteristics and chronic OAT were evaluated to find a correlation with stroke, death, myocardial infarction and bleeding from the access site by Chi-square, Fisher's tests and regression analysis.

Results

502 CAS were performed in a 5-year period. Twelve (2.4%) strokes, 1 (0.2%) death, no myocardial infarctions and 4 (0.8%) access site bleeding occurred in the perioperative period. In the overall population the presence of type 3 or bovine aortic arch was associated with stroke (5.5% vs. 1.5% p = 0.02), and preoperative neurological ischemic symptoms were correlated with higher incidence of the composite event of stroke/death (4.8% vs. 1.4%, p = 0.05). Twenty patients (4.0%) under chronic OAT were submitted to CAS without perioperative bridging heparin therapy with no complications. Overall, patients under OAT had no significantly different outcome compared with patients without OAT.

Conclusions

OAT without perioperative bridging heparin therapy is safe and effective. This data could be useful in the management of patients with chronic OAT submitted to CAS.     

Low protein Z levels but not the protein Z gene G79A polymorphism are a risk factor for ischemic stroke

Background

Protein Z (PZ) is a vitamin K-dependent plasma protein that plays a role in both pro-and anticoagulant pathways, but its exact physiological function remains unclear. The aim of this study was to determine the association between the G79A PZ gene polymorphism in intron F, PZ levels and the occurrence of ischemic stroke.

Methods

We performed a case-control study in 118 Caucasian patients with first ever ischemic stroke or TIA confirmed by CT, and 113 age-and sex-matched population controls. Venous blood samples for PZ levels were collected 7 to 14 days and 3 months after stroke onset. Estimates of relative risk (odds ratios) were adjusted for vascular risk factors.

Results

The adjusted relative risk of ischemic stroke associated with PZ levels in the lowest quartile versus the highest quartile was 3.0 (95% CI: 1.1-8.7) at 7-14 days, and 5.1 (95% CI: 1.2-21.9) at 3 months after the stroke. PZ levels in the convalescent sample were significantly lower than in the acute sample. In the convalescent sample, odds ratios increased with lower quartiles of protein Z level (test for trend p = 0.02). Thirty-nine patients (33%) and 32 (28%) controls were heterozygous for the G79A PZ gene polymorphism and 4 (3%) patients and 4 (4%) controls had the AA-genotype. The PZ levels were significantly lower in subjects with the AA-genotype and intermediate in heterozygote subjects. The odds ratio of ischemic stroke associated with A-allele carriers versus GG-homozygotes was 1.2 (95% CI: 0.7-2.1).

Conclusion

No association between the G79A PZ gene polymorphism and the occurrence of stroke was observed. However, low PZ levels are independently associated with an increased risk of ischemic stroke.     

Prediction of infarct growth and neurologic deterioration in patients with positive perfusion-diffusion mismatch

Background

To assess the value of baseline clinical severity and perfusion–diffusion mismatch as predictors for further infarct growth and clinical outcome.

Methods

Patients with acute ischemic stroke and initial perfusion–diffusion mismatch within 72 h were enrolled. Baseline perfusion defects on time-to-peak (TTP) and cerebral blood volume (CBV) maps were measured. Infarct volume and stroke severity were assessed by diffusion-weighted image (DWI) and NIHSS, and were repeatedly assessed 7 days later. The predictive value of baseline NIHSS and perfusion defects on further infarct growth and neurologic deterioration was determined.

Results

Fifty-two patients (mean age 68.3 ± 12.8 years, 42% women) were enrolled. CBV defects were significantly associated with infarct growth (CBV, p = 0.02). Initial stroke severity, but not TTP and CBV mismatch (p = 0.65 and 0.76, respectively), significantly inversely correlated with neurologic deterioration (p = 0.001).

Conclusions

In patients with mismatch, those with severe symptoms initially are more likely to have infarct growth, while those with minor symptoms tend to suffer from larger extent of neurologic deterioration within 1 week. CBV is associated with further infarct growth but not clinical deterioration.     

Evaluation of the platelet count drop method for assessment of platelet function in comparison with “gold standard” light transmission aggregometry

Introduction

Hyporesponsiveness to antiplatelet agents has been linked to an increased risk of major adverse cardiovascular events. However, light transmission aggregometry (LTA), the gold standard methodology for assessing platelet function, requires expertise and is labour-intensive, which render its use in clinical settings impractical. We assessed whether platelet count drop (PCD), a technique widely available in any haematology laboratory, could replace LTA in testing for inhibition of platelet aggregation induced by antiplatelet agents.

Materials and methods

One hundred and sixty-one coronary artery disease patients taking aspirin alone and 91 patients taking a combination of aspirin and clopidogrel were enrolled. Platelet aggregation was measured by LTA and PCD stimulated with 1.6 mM of arachidonic acid (AA) for aspirin and 5 and 20 μM of adenosine diphosphate (ADP) for clopidogrel.

Results

Correlation between AA-induced LTA and PCD was inexistent (r = - 0.043, p = 0.587), while correlation between ADP-induced LTA and PCD was low (r = 0.374, p < 0.0001 for ADP 5 μM and r = 0.402, p < 0001 for ADP 20 μM). PCD, whether stimulated with AA or ADP, overestimated platelet aggregation as assessed by LTA, by 13-18%. The wide 95% limits of agreement suggest that the assays can disagree significantly in individual patients.

Conclusions

Although the PCD method is widely available in non-specialized laboratories, our results demonstrate that there is poor correlation with the current gold standard, i.e. LTA. Thus, PCD should not be used in replacement of LTA to assess antiplatelet responsiveness.     

Thrombin-activatable fibrinolysis inhibitor genetic polymorphisms as markers of the type of acute coronary syndrome

Introduction

In patients with coronary disease at risk of acute coronary events it is unclear which biological factors could predict the type of acute coronary syndrome clinical presentation. The aim of the study was to investigate the role of genetic polymorphisms in key proteins in fibrinolysis in the type of acute coronary syndrome.

Materials and methods

248 patients with acute coronary syndrome (unstable angina or myocardial infarction) (77% male, mean age 60.75 SD 13.30 years) were prospectively recruited. PAI-1 (type-1 plasminogen activator inhibitor) 4G/5G and TAFI (thrombin-activatable fibrinolysis inhibitor) Ala147Thr, C+1542G, and Thr325Ile polymorphisms were determined by PCR.

Results

147 (59.3%) patients presented with ST-segment elevation acute coronary syndrome (all Q-wave myocardial infarction), and 101 (40.7%) with non-ST-elevation acute coronary syndrome (52 non-Q wave myocardial infarction, and 49 unstable angina). Homozygous TAFI + 1542G and TAFI 325Ile genotypes were less prevalent in patients with ST elevation acute coronary syndrome (p < 0.001, OR: 0.22, 95% CI 0.10-0.50 and p < 0.001, OR: 0.25, 95% CI 0.11-0.55, respectively). There were no differences in TAFI Ala147Thr or PAI genotype distribution between ST elevation and non-ST elevation acute coronary syndrome. In the multivariate analysis including clinical variables, the best model for ST elevation acute coronary syndrome included TAFI + 1542GG (p < 0.001, OR: 0.17, 95% CI 0.07-0.30), age (in years, p < 0.005, OR: 0.97, 95% CI 0.94-0.98) and dyslipidemia (p < 0.005, OR: 2.33, 95% CI 1.42-3.80).

Conclusion

TAFI polymorphism C+1542G and Thr325/Ile are related to the type of acute coronary syndrome. Patients with coronary disease would benefit from individualized cardiovascular prophylaxis based on genetic risk.     

Impact of P2Y12 Inhibitory Effects Induced by Clopidogrel on Platelet Procoagulant Activity in Type 2 Diabetes Mellitus Patients

Introduction

Type 2 diabetes mellitus (T2DM) patients have a variable response profile to the P2Y₁₂ receptor antagonist clopidogrel. P2Y₁₂ receptor signalling promotes platelet procoagulant activity. The aim of this study was to determine if T2DM patients with suboptimal clopidogrel response have greater platelet procoagulant activity compared with optimal responders and evaluate if this can be modulated by enhancing P2Y₁₂ receptor inhibition.

Materials and Methods

A total of 50 T2DM patients in a steady state phase of clopidogrel therapy were studied. Suboptimal responders were randomly assigned to standard (75 mg) or high (150 mg) clopidogrel maintenance therapy for one-month. Afterwards, all patients resumed standard therapy. Platelet procoagulant activity assessed by thrombin-induced platelet-fibrin clot formation using thrombelastography (TEG) was determined at baseline, one-month post-randomization, and one-month after resuming standard therapy.

Results

In the overall study population, the reaction time (R), a measure of time to initial thrombin induced platelet-fibrin clot formation, and the time to maximum rate of thrombin generation (TMRTG) values were 6.3 ± 1.7 and 7.6 ± 1.9 minutes, respectively. Suboptimal clopidogrel responders (n = 30) had acceleration of R (p = 0.002) and TMRTG (p = 0.002) compared to optimal responders (n = 20). Suboptimal clopidogrel responders treated with a 150 mg dose showed prolongation of R (p = 0.0001) and TMRTG (p < 0.0001), which returned to baseline values after resuming standard dosage. No differences were observed among patients randomized to 75 mg.

Conclusions

T2DM patients with suboptimal clopidogrel response have enhanced platelet procoagulant activity compared to patients with optimal response, which can be down-regulated by more potent platelet P2Y₁₂ inhibition using high clopidogrel maintenance dosing.     

Mean platelet volume predicts patency of the infarct-related artery before mechanical reperfusion and short-term mortality in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention

Background and aims

Patency of infarct-related artery (IRA) before mechanical reperfusion with primary percutaneous coronary intervention (PPCI) has been associated with better prognosis in patients with ST-Elevation myocardial infarction (STEMI). Mean platelet volume (MPV) increases in STEMI patients and may be associated with increased thrombotic potential. In STEMI patients scheduled for PPCI we sought to assess whether mean platelet volume (MPV), as measured at admission, correlates with “spontaneous” reperfusion of the IRA and short-term clinical outcome.

Methods

Blood samples were obtained on hospital admission in 617 consecutive patients (82% men; age 64 ± 12 years) with STEMI, before PPCI. 372 (61%) patients were treated with the GP IIb/IIIa blocker abciximab. The main study endpoint was mortality at 30 days.

Results

MPV was significantly lower in patients with basal TIMI flow grade 2 -3 compared to patients with TIMI grade 0-1 (median, 9 vs. 8.5 fL, p < 0.0001). After adjustment, MPV remained an independent predictor of the patency of the IRA (OR 0.63, CI 95% 0.51 - 0.78). A cut off value of 8.95 fL had a predictive negative value of 82% to identify patients with patent IRA. Using this cut point, and after adjusting for confounders, MPV was an independent predictor of 30-day mortality (HR 2.92, CI 95% 1.36 - 6.29). When patients were subdivided according to abciximab use, MPV was a marker of worse outcome but only in patients who did not receive abciximab (HR 3.67, CI 95% 1.13 - 11.49).

Conclusion

An increased MPV is an independent predictor of both a patent IRA (TIMI flow 2 or 3 before PPCI) and 30-day mortality. This marker may be able to identify patients requiring more aggressive antiplatelet therapy.