Acute TNFα levels predict cognitive impairment 6-9 months after COVID-19 infection

BACKGROUND

A neurocognitive phenotype of post-COVID-19 infection has recently been described that is characterized by a lack of awareness of memory impairment (i.e., anosognosia), altered functional connectivity in the brain's default mode and limbic networks, and an elevated monocyte count. However, the relationship between these cognitive and brain functional connectivity alterations in the chronic phase with the level of cytokines during the acute phase has yet to be identified.

AIM

Determine whether acute cytokine type and levels is associated with anosognosia and functional patterns of brain connectivity 6-9 months after infection.

METHODS

We analyzed the predictive value of the concentration of acute cytokines (IL-1RA, IL-1β, IL-6, IL-8, IFNγ, G-CSF, GM-CSF) (cytokine panel by multiplex immunoassay) in the plasma of 39 patients (mean age 59 yrs, 38-78) in relation to their anosognosia scores for memory deficits via stepwise linear regression. Then, associations between the different cytokines and brain functional connectivity patterns were analyzed by MRI and multivariate partial least squares correlations for the whole group.

RESULTS

Stepwise regression modeling allowed us to show that acute TNFα levels predicted (R² = 0.145; β = -0.38; p = .017) and were associated (r = -0.587; p < .001) with scores of anosognosia for memory deficits observed 6-9 months post-infection. Finally, high TNFα levels were associated with hippocampal, temporal pole, accumbens nucleus, amygdala, and cerebellum connectivity.

CONCLUSION

Increased plasma TNFα levels in the acute phase of COVID-19 predict the presence of long-term anosognosia scores and changes in limbic system functional connectivity.

Frequency of Abnormally Low Neuropsychological Scores in Post-COVID-19 Syndrome: the Geneva COVID-COG Cohort

OBJECTIVE

Several studies have reported poor long-term neuropsychological performances in patients following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, but none has yet considered the effect of administering multiple intercorrelated neuropsychological tests and assessed the frequency of cognitive deficits in a normative population. Our aim was therefore to assess the presence of cumulative neuropsychological deficits in an actual post-coronavirus disease of 2019 (COVID-19) comparison group versus one simulated using Monte-Carlo methods.

METHOD

Validated neuropsychological Monte-Carlo simulation methods were applied to scores from a battery of neuropsychological tests (memory, executive, attentional, perceptual, logical reasoning, language, and ideomotor praxis) administered to 121 patients who had had mild, moderate, or severe COVID-19 (mean age: 56.70 years; 32% women), 222 ± 43 days post-infection. The cumulative percentages of the three severity subgroups were compared with the results of a false discovery rate-corrected probability analysis based on normative data.

RESULTS

The cumulative percentages of deficits in memory and executive functions among the severe and moderate patients were significantly higher than those estimated for the normative population. Moderate patients also had significantly more deficits in perception and logical reasoning. In contrast, the mild group did not have significantly more cumulative deficits.

CONCLUSIONS

Moderate and severe forms of COVID-19 cause greater long-term neuropsychological deficits than those that would be found in a normative population, reinforcing the hypothesis of long-term effects of SARS-CoV-2 on cognitive function, independent of the severity of the initial infection.

Functional Independence Measure score is associated with mortality in critically ill elderly patients admitted to an intermediate care unit

Background

Age alone is not a robust predictor of mortality in critically ill elderly patients. Chronic health status and functional status before admission could be better predictors. This study aimed to determine whether functional status, assessed using the Functional Independence Measure (FIM), could be an independent predictor of mortality in a geriatric population admitted to an intermediate care unit (IMCU).

Methods

A monocentric, retrospective, observational study of all patients aged ≥75 years old admitted to Geneva University Hospitals’ geriatric IMCU between 01.01.2012 and 31.05.2016. The study’s primary outcome metrics were one-year mortality’s associations with a pre-admission FIM score and other relevant prospectively recorded prognostic variables.

Results

A total of 345 patients were included (56% female, mean age 85 +/− 6.5 years). Mean FIM score was 66 +/− 26. One-year mortality was 57%. Dichotomized low (≤ 63) and high FIM (> 63) scores were associated with one-year mortalities of 68 and 44%, respectively. Logistic regression calculations found an association between pre-admission FIM score and one-year mortality (p <  0.0001), including variables usually associated with mortality (e.g., age, sex, comorbidities, mini-mental health state score, renal function). Multivariate survival analysis showed a significant difference between groups, with a hazard ratio of 0.29 (95% CI: 0.13–0.65) for patients with high FIM scores.

Conclusions

In the present study, higher functional status, assessed using the FIM tool before admission to an IMCU, was significantly and independently associated with lower one-year mortality. This opens up perspectives on the potential value of FIM for establishing a finer prognosis and better triage of critically ill older patients.

Accuracy of comprehensive PCR analysis of nasopharyngeal and oropharyngeal swabs for CT-scan-confirmed pneumonia in elderly patients: a prospective cohort study

OBJECTIVES

We aimed to assess the accuracy of PCR detection of viruses and bacteria on nasopharyngeal and oropharyngeal swabs (NPS) for the diagnosis of pneumonia in elderly individuals.

METHODS

We included consecutive hospitalized elderly individuals suspected of having pneumonia. At inclusion, NPS were collected from all participants and tested by PCR for the presence of viral and bacterial respiratory pathogens (index test, defined as comprehensive molecular testing). Routine diagnostic tests (blood and sputum culture, urine antigen detection) were also performed. The reference standard was the presence of pneumonia on a low-dose CT scan as assessed by two independent expert radiologists.

RESULTS

The diagnosis of pneumonia was confirmed in 127 of 199 (64%) included patients (mean age 83 years, community-acquired pneumonia in 105 (83%)). A pathogen was identified by comprehensive molecular testing in 114 patients (57%) and by routine methods in 22 (11%). Comprehensive molecular testing was positive for viruses in 62 patients (31%) and for bacteria in 73 (37%). The sensitivity and specificity were 61% (95% CI 53%-69%) and 50% (95% CI 39%-61%) for comprehensive molecular testing, and 14% (95% CI 82%-21%) and 94% (95% CI 86%-98%) for routine testing, respectively. Positive likelihood ratio was 2.55 for routine methods and 1.23 for comprehensive molecular testing.

CONCLUSION

Comprehensive molecular testing of NPS increases the number of pathogens detected compared with routine methods, but results are poorly predictive of the presence of pneumonia. Hence, comprehensive molecular testing is unlikely to impact clinical decision-making (NCT02467192).

CLINICAL TRIALS REGISTRATION

NCT02467192.

Coadministration of ticagrelor and ritonavir: Toward prospective dose adjustment to maintain an optimal platelet inhibition using the PBPK approach

Ticagrelor is a potent antiplatelet drug metabolized by cytochrome (CYP)3A. It is contraindicated in patients with human immunodeficiency virus (HIV) because of the expected CYP3A inhibition by most protease inhibitors, such as ritonavir and an increased bleeding risk. In this study, a physiologically based pharmacokinetic (PBPK) model was created for ticagrelor and its active metabolite (AM). Based on the simulated interaction between ticagrelor 180 mg and ritonavir 100 mg, a lower dose of ticagrelor was calculated to obtain, when coadministered with ritonavir, the same pharmacokinetic (PK) and platelet inhibition as ticagrelor administered alone. A clinical study was thereafter conducted in healthy volunteers. Observed PK profiles of ticagrelor and its AM were successfully predicted with the model. Platelet inhibition was nearly complete in both sessions despite administration of a fourfold lower dose of ticagrelor in the second session. This PBPK model could be prospectively used to broaden the usage of ticagrelor in patients with ritonavir-treated HIV regardless of the CYP3A inhibition.

[My patient is too old for a lipid-lowering therapy: myths and reality]

Lipid-lowering treatment in the elderly patient is conditioned by a high incidence and prevalence of cardiovascular disease in the setting of a limited remaining life span. The clinical benefit of statin therapy can be seen after a few months, thus supporting use in secondary prevention even when the lifespan is restricted to a few years. Recent guidelines propose the use of moderate doses in the elderly > 75 years. The evidence for treatment in primary prevention is weaker and the evaluation of the total cardiovascular risk is complicated by the high baseline risk of many elderly. Rational treatment decisions should be based on biologic rather than chronologic age. Statins are generally well tolerated in the elderly, requiring clinical monitoring only, with particular attention to pharmacokinetic interactions and renal failure.

[Pneumonia in the elderly: are there any specificities? ]

Pneumonia is one of the leading causes of death in the elderly. Streptococcus pneumoniae is the leading etiological agent, but the identification of a pathogen remains infrequent despite advances in microbiological methods. Antibiotic resistant organisms should be considered as potential causal agents in recently hospitalized patients and patients with recent antibiotic exposure and influenza during the flu season. The clinical diagnosis is difficult due to frequent atypical presentation. Prognostic scores are not always appropriate to predict the need for hospitalization in very old patients. Studies on the role of low-dose chest CT for the diagnosis, management and prevention should help improve the management of this disease in the future.

The paraoxonase-1 pathway is not a major bioactivation pathway of clopidogrel in vitro

BACKGROUND AND PURPOSE

Clopidogrel is a prodrug bioactivated by cytochrome P450s (CYPs). More recently, paraoxonase-1 (PON1) has been proposed as a major contributor to clopidogrel metabolism. The purpose of this study was to assess the relative contribution of CYPs and PON1 to clopidogrel metabolism in vitro.

EXPERIMENTAL APPROACH

Clopidogrel metabolism was studied in human serum, recombinant PON1 enzyme (rePON1), pooled human liver microsomes (HLMs), HLMs with the CYP2C19*1/*1 genotype and HLMs with the CYP2C19*2/*2 genotype. Inhibition studies were also performed using specific CYP inhibitors and antibodies. Clopidogrel and its metabolites were measured using LC/MS/MS method.

KEY RESULTS

PON1 activity was highest in the human serum and there was no difference in PON1 activity between any of the HLM groups. The production of clopidogrel's active metabolite (clopidogrel-AM) from 2-oxo-clopidogrel in pooled HLMs was approximately 500 times that in serum. When 2-oxo-clopidogrel was incubated with rePON1, clopidogrel-AM was not detected. Clopidogrel-AM production from 2-oxo-clopidogrel was lower in CYP2C19*2/*2 HLMs compared with CYP2C19*1/*1 HLMs, while PON1 activity in HLMs with both genotypes was similar. Moreover, incubation with inhibitors of CYP3A, CYP2B6 and CYP2C19 significantly reduced clopidogrel bioactivation while a PON1 inhibitor, EDTA, had only a weak inhibitory effect.

CONCLUSION AND IMPLICATIONS

This in vitro study shows that the contribution of PON1 to clopidogrel metabolism is limited at clinically relevant concentrations. Moreover, CYP2C19, CYP2B6 and CYP3A play important roles in the bioactivation of clopidogrel.

[Practical implementation and usefulness of guidelines for the management of syncope: a professional practice study]

AIMS

To assess the practical implementation of international guidelines and their impact on syncope management in a 500-bed general hospital.

PATIENTS AND METHODS

Three groups of 63 consecutive patients admitted for syncope to the emergency care unit (ECU) were studied: group 1, before the guidelines delivered to the practitioners, group 2 immediately after the diffusion of guidelines and group 3, one year later. The study evaluates the mean duration of stay (MDS) and the relevance of the diagnostic strategy.

RESULTS

In group 1 compared to group 2, MDS were respectively 6.8±5.5 and 5.4±2.8 days (P=0.07) and the unexplained syncope number respectively 22% and 24% (P=0.8). The search of orthostatic hypotension became more systematic (13% versus 86% in group 1 and 2 respectively, P<0.001). The agreement (kappa coefficient) between initial and final diagnostic increased in 0.34 to 0.44. One year later MDS in group 3 was 7.1±4.7 days (P=0.8 versus group 1 and P=0.015 versus group 2) with only 6.3% systematic search for orthostatic hypotension (P<0.001).

CONCLUSIONS

Guidelines optimize the syncope management in the ECU and the agreement between the emergency and discharge diagnostic without change of unexplained syncope and. MDS tend to be shorter when guidelines are actively implemented. Nevertheless, the positive impact of guidelines implementation is of limited duration.

Influence of the paraoxonase-1 Q192R genetic variant on clopidogrel responsiveness and recurrent cardiovascular events: a systematic review and meta-analysis

BACKGROUND

A poor biological response to clopidogrel is associated with an increased risk of major cardiovascular ischemic events (MACE). Paraoxonase 1 (PON1) enzyme activity is modulated by the PON1-Q192R variant (rs662) and was recently suggested to be strongly involved in clopidogrel bioactivation, but the influence of the PON1-Q192R variant on the risk of MACE in clopidogrel-treated patients is controversial.

OBJECTIVES

To determine whether the PON1-Q192R variant influences clopidogrel biological responsiveness and the risk of MACE in patients treated with clopidogrel.

METHODS

Systematic review and meta-analysis of studies of the association between the PON1-Q192R polymorphism and the biological response to clopidogrel and/or the risk of MACE during clopidogrel administration.

RESULTS

Seventeen studies were included. In the 12 studies of the biological response to clopidogrel (n = 5302 patients), there was no significant difference between 192QQ and 192QR + 192RR subjects, whatever the laboratory method used (global mean standardized difference = 0.10 [-0.06; 0.25], P = 0.22). Eleven studies assessed the risk of MACE, four using a case-control design (n = 2739 patients) and seven a prospective design (n = 5353 patients). Overall, MACE occurred in 19% of patients in case-control studies and in 6% of patients in prospective cohort studies, with no significant difference between 192QQ and 192QR + 192RR patients (OR = 1.28 [0.97; 1.68], P = 0.08). Similar results were obtained when study design was taken into account. Heterogeneity was mainly driven by one publication.

CONCLUSIONS

This meta-analysis suggests that the PON1-Q192R polymorphism has no major impact on the risk of MACE and does not alter the biological response to clopidogrel in clopidogrel-treated patients.

[Distal coronary thrombosis during L-asparaginase treatment for an acute lymphoblastic leukaemia]

A 53-year-old man is treated by L-asparaginase for an acute lymphoblastic leukaemia. He received anti thrombin infusions. A systematic electrocardiogram showed an asymptomatic subepicardium ischemia without troponin elevation. Echocardiography and heart magnetic resonance imaging showed an apical thrombus facing a zone of myocardial necrosis. A thrombus regression was observed under anticoagulation. Atypical and asymptomatic coronary thrombosis may occur following L-asparaginase treatment. Regular electrocardiogram monitoring is proposed along this treatment. Arterial thrombosis associated with anti tumor chemotherapies are reviewed.

Clinical predictors of dual aspirin and clopidogrel poor responsiveness in stable cardiovascular patients from the ADRIE study

BACKGROUND

Poor response to both aspirin and clopidogrel (dual poor responsiveness [DPR]) is a major risk factor for recurrent ischemic events.

OBJECTIVES

The aim of this study was to identify factors associated with DPR, defined with specific tests, and derive a predictive clinical score.

METHODS

We studied 771 consecutive stable cardiovascular patients treated with aspirin (n = 223), clopidogrel (n = 111), or both drugs (n = 37). Aspirin responsiveness was evaluated by serum thromboxane (Tx)B₂ assay, and clopidogrel responsiveness by calculating the platelet reactivity index (PRI) on the basis of the phosphorylation status of the vasodilator phosphoprotein. The analysis was focused on patients treated with both drugs, and on independent predictors of DPR.

RESULTS

Among patients on dual therapy, there was no relevant correlation between TxB₂ levels and PRI values (r = 0.11). Sixty-seven patients (15.4%) had DPR. Diabetes [odds ratio (OR) 1.89, 95% confidence interval (CI) 1.06-3.39], high body weight (> 86 kg vs. < 77 kg, OR 4.74, 95% CI 2.49-9.73), low aspirin dose (75-81 mg vs. ≥ 160 mg, OR 0.12, 95% CI 0.09-0.93) and high C-reactive protein (CRP) level (> 1.6 mg L⁻¹ vs. < 0.6 mg L⁻¹, OR 3.66, 95% CI 1.74-8.72) were independently associated with DPR, via increased TxB(2) levels, increased PRI, or both. These associations with TxB₂ and PRI were reproduced across the whole population. With use of a factor-weighed score (c-index = 0.74), the predicted prevalence of DPR was 57% in the highest strata of the score as compared with < 4% for the lowest strata.

CONCLUSIONS

Diabetes, body weight, the aspirin dose and CRP levels are readily available independent predictors of DPR, and some are potential targets for reducing its prevalence.

Clinical implications of clopidogrel non-response in cardiovascular patients: a systematic review and meta-analysis

BSUMMARY BACKGROUND: Previous studies have shown an important risk of cardiovascular events in patients with clopidogrel biological non-response, and data have shown considerable, unexplored heterogeneity.

OBJECTIVES

To evaluate the magnitude of cardiovascular risk associated with clopidogrel non-response and to explore heterogeneity.

METHODS

This was a systematic review and meta-analysis of prospective studies of patients treated with clopidogrel for symptomatic atherothrombosis, evaluated by light transmission aggregometry with ADP and monitored prospectively for clinical ischemic events.

RESULTS

Fifteen studies were included, totaling 3960 patients, of whom 25% were considered to be clopidogrel non-responders. The global relative risk (RR) for recurrent ischemic events in clopidogrel non-responders was 3.5 [95% confidence interval (CI) 2.4-5.2, P < 0.0001]. The results of the different studies were heterogeneous (Cochran P = 0.01 and I(2) = 52%). The most recent studies yielded lower RRs [global RR = 2.9 (95% CI 2.3-3.8) after 2007, and global RR = 6.6 (95% CI 3.7-11.9) before 2007, P = 0.01]. Heterogeneity was present in the group of studies in which more than 10% of patients took glycoprotein (GP)IIb-IIIa inhibitors [Cochran P = 0.003 and I(2) = 70%; RR = 3.8 (95% CI 2.9-5.1)] and was absent in the other studies [Cochran P = 0.88 and I(2) = 0; RR = 2.5 (95% CI 1.7-3.6)]. The RR was significantly higher in studies using higher ADP maximal aggregation cut-offs (> 65%) for clopidogrel non-response than in studies using lower cut-offs [RR = 5.8 (95% CI 3.2-10.3) and RR = 2.9 (95% CI 2.2-3.7), respectively, P = 0.03].

CONCLUSIONS

The risk of ischemic events associated with clopidogrel non-response is now more precisely defined. The risk is heterogeneous across studies, possibly because of an interaction with GPIIb-IIIa inhibitors and the use of different cut-offs to identify non-responders.

Paternal endothelial protein C receptor 219Gly variant as a mild and limited risk factor for deep vein thrombosis during pregnancy

BACKGROUND

Half of all venous thromboembolism (VTE) cases during pregnancy are associated with a maternal thrombophilia. The influence of paternal genotype on the placenta and in the genesis of VTE has not been described.

OBJECTIVES

To determine if the maternal and paternal Ser219Gly dimorphism of the endothelial protein C receptor (EPCR), evaluated through detection of the PROCR 6936G allele, is a risk factor for VTE during pregnancy.

METHODS

Using a case-control study nested in the NOHA first cohort of primigravidae, 66 patient couples with a first episode of gestational VTE and randomly selected non-thrombotic control couples were investigated. For each couple, factor V gene (F5) G1691A, factor II gene (F2) G20210A, factor XII gene (F12) C46T and PROCR A6936G polymorphisms were determined.

RESULTS

Only maternal F5 1691A, F2 20210A and F12 46T alleles were independently associated with iliac and infra-iliac deep vein thromboses (DVT). The maternal PROCR 6936G allele was a mild risk factor for iliac DVT (OR = 5.5 [2.3-13.0]). The paternal PROCR 6936G allele was also a mild independent risk factor for iliac DVT (OR = 2.6 [1.1-6.2]) and only during pregnancy (rather than postpartum) among maternal carriers of the F5 1691A allele (OR = 77.6 [4.2 to > 999.9]).

CONCLUSIONS

The paternal PROCR 6936G allele could be a risk factor for maternal iliac DVT. Its impact was milder than the F5 1691A and F2 20210A polymorphisms in mothers. We hypothesize that the prothrombotic effect of the paternal PROCR 6936G allele is localized. Therefore, DVT during pregnancy may be influenced by trophoblastic cell-surface proteins inherited from both maternal and paternal alleles.

[Acute Q fever, antiphopholipid antibodies and renal artery thrombosis: case report and literature review]

INTRODUCTION

Antiphospholipid antibodies (aPL) can be associated with numerous infectious and particularly Q fever. Data on the pathogenicity of aPL in the course of acute Q fever are scarce.

CASE REPORT

We report the case an acute Coxiella burnetii infection associated with clinical and biological manifestations of the aPL syndrome, including a renal infarction. Along with antibiotic treatment, anticoagulation and intravenous immunoglobulins, the clinical outcome was favourable. Antiphospholipid antibodies and Q fever antibody titers had a closely related evolution.

CONCLUSION

Arterial thrombosis associated with Q fever and aPL is exceptional. The nosology and potential mechanisms are discussed.

Use of the PFA-100 closure time to predict cardiovascular events in aspirin-treated cardiovascular patients: a systematic review and meta-analysis

BACKGROUND

PFA-100 is a point-of-care assay that evaluates platelet reactivity in high-shear-stress conditions by measuring the closure time (CT) of a membrane aperture. When determined with a collagen/epinephrine cartridge (CEPI), the CT is usually prolonged by aspirin. Studies of the predictive value of a short PFA-100CT(CEPI) for ischemic events in aspirin-treated patients have given variable results.

OBJECTIVES

To conduct a systematic review and meta-analysis of studies on the clinical predictive value of a short PFA-100CT(CEPI) in aspirin-treated cardiovascular patients.

PATIENTS AND METHODS

Relevant studies were identified by scanning electronic databases. Studies were selected if they included aspirin-treated patients with symptomatic atherosclerosis, measured the PFA-100CT(CEPI), used a CT cut-off value to define aspirin 'responders' and 'non-responders', and reported ischemic events.

RESULTS

We selected seven non-prospective studies (1466 patients) and eight prospective studies (1227 patients). In non-prospective studies, the PFA-100CT(CEPI) was performed after the ischemic clinical endpoint, and a publication bias was identified. In prospective studies, the global odds ratio (OR) for the recurrence of an ischemic event in 'aspirin non-responders' relative to 'aspirin responders' was 2.1 [95% confidence interval (CI) 1.4-3.4, P < 0.001]. Pooled analysis with a random effect model revealed no heterogeneity (Q Cochran P = 0.36 and I(2) = 9.4%).

CONCLUSIONS

A short PFA-100CT(CEPI) is associated with increased recurrence of ischemic events in aspirin-treated cardiovascular patients. This finding needs to be confirmed in stable ischemic patients, and the PFA-100CT(CEPI) cut-off needs to be refined in these patients.

New Antiplatelet Strategies in Atherothrombosis and Their Indications

Antiplatelet agents (APA) are used to reduce the risk of major cardiovascular events in various settings. When used for secondary prevention, antiplatelet monotherapy is associated with a relative risk reduction of such ischemic events of 25% compared to a placebo. New strategies are based on dual APA therapy. Aspirin-clopidogrel combination therapy is effective in situations of acute vessel injury such as myocardial infarction, coronary stenting and, possibly, peripheral stenting. GPIIb/IIIa inhibitors and loading doses of clopidogrel also have a place in these acute settings. In contrast, the aspirin-clopidogrel combination has proven disappointing in stable patients with cardiovascular disease, with no beneficial effect and, often, more bleeding events. Combination therapy with aspirin and extended-release dipyridamole may be more beneficial than very low doses of aspirin in ischemic stroke, but its use is limited by adverse effects. Overall, aspirin remains the first-line monotherapy of choice for patients with atherothrombosis, while clopidogrel is a valuable alternative. New antiplatelet strategies are in the pipeline, and clinically relevant laboratory tests of APA response may soon help to tailor treatment.

Traitement médical de l'artériopathie oblitérante des membres inférieurs: étude de pratique professionnelle chez 262 patients

PURPOSE

Antiplatelet agents (APA), statins and angiotensin converting enzyme inhibitors (ACEI) are effective to reduce the risk of cardio-vascular events in patients with peripheral arterial disease (PAD). Few data are available on the actual prescription of these drugs in outpatients and on the effect of hospital care on the level of prescription.

METHODS

Retrospective study of patients hospitalized with a confirmed diagnosis of PAD over a one-year period. Comparison of medical treatments on admission and on discharge.

RESULTS

262 patients were included. Mean age was 73 +/- 11 years, and 29% of the patients were women. APA were present in 64% on admission and in 83% when discharged (P < 0.0001). A statin was present in 29% on admission and in 38% when discharged (P = 0.001). ACEI were present in 27% on admission and in 32% when discharged (P= 0.02). A vasodilator was present in 47% on admission and 52% when discharged (P = 0.1). 35% of the patients had isolated PAD. Compared to the patients with associated clinical coronary or cerebro-vascular disease, they were less frequently discharged on statins (respectively 26 and 45%, p = 0.003) and on ACEI (respectively 23 et 38%, P = 0.016) whereas APA were equally prescribed (respectively 82 and 84%, P= 0.7).

CONCLUSION

APA were prescribed to a majority of outpatients and the level of prescription was further improved when patients were discharged from the hospital. Statins and ACEI were insufficiently prescribed. On the other hand, vasodilator therapy remained still largely prescribed, despite the lack of any strong effect on morbidity and survival.

[Haemostasis. Aspirin and clopidogrel platelet resistances]

Articles on antiplatelet "resistance" or "nonresponder" subjects now appear in the medical literature or in the media on a regular basis. The clinical consequences of such biological resistances are yet uncertain. In this review, we describe the concepts of specific and non specific resistances according to the tests used and summarize the main studies up to now. If antiplatelet drug resistances are shown to be predictive of cardiovascular events in large prospective studies, tailoring antiplatelet drugs could be beneficial and, therefore, warranted. New compounds with a more potent effect are emerging and might be useful in clinically relevant resistances.

Pharmacogénétique et médicaments antiplaquettaires

PURPOSE

The observation of inherited drug response variability gave rise to the field of pharmacogenetics. Pharmacogenetic research on drug targets, particularly platelet enzymes and receptors, is more recent and is becoming an emerging field.

CURRENT KNOWLEDGE AND KEY POINTS

In the Framingham study, the heritability of platelet aggregation response ranges from 44 to 62%, depending on the agonists used. The gene coding for GPIIIa, a sub-unit of the fibrinogen receptor GPIIbIIIa, is one of the most extensively studied gene in relation with aggregation tests and antiplatelet drugs. The GPIIIa PLA1/PLA2 polymorphism has been associated with clopidogrel and orbofiban platelet response. However, data are more controversial concerning the association with aspirin response. Recently, Cox-1 and GPIa (part of the GPIaIIa collagen receptor) genetic variations have also been pointed out as possible candidates to explain part of the variability of the response to antiplatelet agents. Finally, the H1/H2 polymorphism of the platelet ADP receptor P2Y12 gene has been associated with ADP-induced platelet aggregation response and peripheral arterial disease. This polymorphism may modulate the effect of P2Y12 antagonists like clopidogrel and its clinical implication is currently under study.

FUTURE PROSPECTS AND PROJECTS

Gene-expression profiling and proteomics may allow the identification of new candidate genes whose variations may be associated with the heritability of platelet aggregation response. In the next future, phenotypic or genotypic studies could be available to tailor the prescription of antiplatelet drugs.

The specific thromboxane receptor antagonist S18886: pharmacokinetic and pharmacodynamic studies

OBJECTIVES AND PATIENTS

We conducted a multicenter double-blind pharmacokinetic/pharmacodynamic (PK/PD) study of the new oral thromboxane receptor antagonist S18886 in 30 patients with peripheral artery disease, who were randomized to receive five different oral dosages of S18886 (1, 2.5, 5, 10 or 30 mg) for 12 weeks (83 days). Primary objective was to determine the effect of S18886 on platelet aggregation ex vivo.

RESULTS

Pharmacokinetics of S18886 was linear, with peak plasma levels being reached between 30 min and 2 h and a terminal half-life of 5.8-10 h. No significant accumulation of S18886 in plasma was observed after repeated dosing. The relationship between the S18886 concentration and platelet inhibition was examined in terms of U46619-induced platelet aggregation. Over the range of doses studied, there was a predictable relation between the plasma drug concentration and the degree of platelet inhibition at each dose. Maximal inhibition of U46619-induced platelet aggregation was achieved within 1 h with all oral doses of S18886, and this effect was maintained for at least 12 h. The PK/PD relationship was direct, and U46619-induced platelet aggregation was strongly inhibited by S18886 plasma concentrations above 10 ng mL(-1). This concentration was thus the minimal effective antiplatelet level in this population, and was maintained only by the dosages of 10 and 30 mg. The safety profile of S18886 was excellent, whatever the unit dose, with no attributable adverse events.

CONCLUSION

The results of this study, which included modeling and simulation, help identify the minimal effective plasma concentration of S18886 required for potent antiplatelet efficacy in patients with stable peripheral arterial disease.

The factor II G20210A gene polymorphism, but not factor V Arg506Gln, is associated with peripheral arterial disease: results of a case-control study

BACKGROUND

The FIIG20210A polymorphism has been associated with arterial wall thickness and atherothrombotic diseases in selected subgroups. The FVArg506Gln polymorphism does not seem to be associated with arterial diseases. Few data are available on these polymorphisms and the risk of peripheral arterial disease (PAD).

OBJECTIVES

To study the association between the FIIG20210A and FVArg506Gln polymorphisms and PAD and its clinical severity. To examine the potential interactions with traditional vascular risk factors.

PATIENTS AND METHODS

We studied 184 consecutive male patients under 70 years of age with symptomatic PAD and 330 age-matched male controls free of symptomatic PAD and with no cardiovascular history. We evaluated the FIIG20210A and FVArg506Gln polymorphisms in all subjects.

RESULTS

Mean age was 57.1 +/- 7.2 years (cases) and 56.7 +/- 7.6 years (controls). The FII20210A allele was more frequent in PAD patients with odds ratios (OR) of 3.77 (1.39-10.2) in univariate analysis and 4.30 (1.3-14.7) after adjustment for diabetes, smoking, hypertension and hypercholesterolemia. In smokers or past smokers the magnitude of the association was markedly increased but there was no evidence of an interaction between tobacco exposure and FIIG20210A. In case subjects, the FII20210A allele was also associated with critical ischemia [OR = 4.1 (1.1-15.7), P = 0.039 in multivariate analysis]. FVArg506Gln was not associated with PAD [OR = 0.65 (0.27-1.54) and 0.77 (0.28-2.1) in univariate and multivariate analyses, respectively].

CONCLUSIONS

The FIIG20210A gene polymorphism may be a risk factor for PAD and its severity. In contrast, the FVArg506Gln polymorphism is not associated with PAD.

Combined effect of factor V Leiden and prothrombin 20210A on the risk of venous thromboembolism--pooled analysis of 8 case-control studies including 2310 cases and 3204 controls. Study Group for Pooled-Analysis in Venous Thromboembolism

Factor V Leiden and factor II G20210A mutations are two frequent genetic risk factors involved in venous thromboembolism (VTE). The goal of this pooled analysis of 8 case-control studies, comprising a total of 2310 cases and 3204 controls, was to precisely estimate the risk of VTE in patients bearing both mutations (double heterozygotes). Odds ratios for VTE were 4.9 (95% CI; 4.1-5.9) for the factor V Leiden and 3.8 (3.0-4.9) for the factor II G20210A mutation. Fifty-one cases (2.2%) and none of the controls were double heterozygotes. The odds ratio for venous thrombosis in double heterozygotes was 20.0 (11.1-36.1). Twelve percent of patients heterozygous for factor V Leiden were also heterozygous for factor II G20210A and conversely 23% of patients heterozygous for factor II G20210A were also heterozygous for factor V Leiden. Furthermore, in this large population we analyzed the effect of oral contraceptive (OC) in women carrying one of these mutations. Odds ratio for VTE associated with OC was 2.29 (1.72-3.04). In factor V Leiden carriers using OC, the odds ratio for VTE was 10.25 (5.69-1 8.45). The odds ratio of the association of factor II mutation and OC use was 7.14 (3.39-15.04). Finally, we also confirmed that the frequency of factor V Leiden was lower in patients with pulmonary embolism than in patients with deep vein thrombosis without PE (odds ratio 0.69). Conversely, factor II G20210A mutation was equally balanced in both patient groups.

Combined effect of factor V Leiden and prothrombin 20210A on the risk of venous thromboembolism--pooled analysis of 8 case-control studies including 2310 cases and 3204 controls. Study Group for Pooled-Analysis in Venous Thromboembolism

Factor V Leiden and factor II G20210A mutations are two frequent genetic risk factors involved in venous thromboembolism (VTE). The goal of this pooled analysis of 8 case-control studies, comprising a total of 2310 cases and 3204 controls, was to precisely estimate the risk of VTE in patients bearing both mutations (double heterozygotes). Odds ratios for VTE were 4.9 (95% CI; 4.1-5.9) for the factor V Leiden and 3.8 (3.0-4.9) for the factor II G20210A mutation. Fifty-one cases (2.2%) and none of the controls were double heterozygotes. The odds ratio for venous thrombosis in double heterozygotes was 20.0 (11.1-36.1). Twelve percent of patients heterozygous for factor V Leiden were also heterozygous for factor II G20210A and conversely 23% of patients heterozygous for factor II G20210A were also heterozygous for factor V Leiden. Furthermore, in this large population we analyzed the effect of oral contraceptive (OC) in women carrying one of these mutations. Odds ratio for VTE associated with OC was 2.29 (1.72-3.04). In factor V Leiden carriers using OC, the odds ratio for VTE was 10.25 (5.69-1 8.45). The odds ratio of the association of factor II mutation and OC use was 7.14 (3.39-15.04). Finally, we also confirmed that the frequency of factor V Leiden was lower in patients with pulmonary embolism than in patients with deep vein thrombosis without PE (odds ratio 0.69). Conversely, factor II G20210A mutation was equally balanced in both patient groups.

[Diabetic foot ulcers: anti-infectious strategies]

Infection is a common problem in diabetic patients with foot ulcers. The diagnosis of infection is not always easy to establish, but must be made for proper therapeutic decision making. In addition to local care, search for arteriopathy and strict control of blood glucose, treatment of infected foot ulcers requires an appropriate anti-infectious strategy. We developed diagnostic and therapeutic decisional algorithms from data available in the literature in order to establish a management strategy for different clinical situations. The fundamental role of clinical assessment is underlined and the different causal microorganisms are recalled, together with the anti-microbial activity and bone concentrations of the main antibiotics used. An optimal anti-infection work-up can undoubtedly significantly reduce the number of amputations in diabetic patients.

[Value of helical CT in Takayasu arteritis]

In the past, the diagnosis and course of Takayasu arteritis were monitored by following angiographic findings, in addition to clinical symptoms and biological tests. More recently, cross-sectional imaging techniques especially Computed Tomography (CT) depicted mural changes in aorta and main vessels in this disease. Within the same acquisition, spiral mode also allows to show luminal changes, similarly to conventional angiography. In addition to its diagnostic value especially in the early phase of the disease, CT seems accurate in the follow-up of treated patients and may be proposed as a therapeutic guide. CT features are presented, according to the stage of the disease and the vessels involved.

Individual smallest detectable difference in bone mineral density measurements

Bone mineral density (BMD) measurement is a major outcome measure in osteoporosis. The BMD changes observed must exceed the variability inherent in the measurement process to be considered related to disease progression. The objective of the study was to estimate short-term variability of BMD measurement and to propose a cut-off value for the smallest detectable BMD changes for an individual. To estimate the short-term variability, 70 healthy postmenopausal women aged 53 +/- 4 years (group 1) and 57 elderly osteoporotic postmenopausal women aged 80 +/- 6 years (group 2) had two repeated BMD measurements of the lumbar spine (L2-L4) and the proximal femur with dual-energy X-ray absorptiometry, with complete repositioning within 1 h. Cut-offs derived from short-term variability were either estimated from the coefficient of variation (CV) (which is a function of the measured value) or from the standard deviation (SD), and applied to 330 postmenopausal women (group 3) who had BMD measurements at baseline and 2 years later. The short-term intrasubject variability was greater at the lumbar spine in group 2 versus group 1 (0.0123 vs. 0.0059 g/cm2, p < 10-4), whereas it was not at the femoral neck (0.0098 vs. 0.0076 g/cm2, p = 0.28). There was no statistically significant correlation between short-term intrasubject variability (SD) and BMD as demonstrated with an analysis of covariance (p values ranging from 0.17 to 0.90). Cut-offs estimated with SD and CV were individually applied to group 3 patients. Using these two cut-offs, discrepancies in assessment of progression were observed in 1.7-8.6% of cases. Short-term BMD variability is constant in a wide range of BMD values. Consequently, to determine cut-off values for the smallest detectable differences in BMD at the individual level, precision errors should be based on SD (expressed in absolute units) rather than on CV (expressed in percentage).

Renal and metabolic clearance of N-acetyl-seryl-aspartyl-lysyl-proline (AcSDKP) during angiotensin-converting enzyme inhibition in humans

We investigated the contributions of angiotensin-converting enzyme (ACE) and glomerular filtration to creating the new metabolic balance of the hemoregulatory peptide N-acetyl-seryl-aspartyl-lysyl-proline (AcSDKP) that occurs during acute and chronic ACE inhibition in healthy subjects. We also studied the effect of chronic renal failure on the plasma concentration of AcSDKP during long-term ACE inhibitor (ACEI) treatment or in its absence. In healthy subjects, a single oral dose of 50 mg captopril (n=32) and a 7-day administration of 50 mg captopril BID (n=10) resulted in a respective 42-fold (range, 18- to 265-fold) and 34-fold (range, 24-fold to 45-fold) increase in the ratio of urinary AcSDKP to creatinine accompanied by a 4-fold (range, 2- to 6.8-fold) and 4.8-fold (range, 2.6- to 11.8-fold) increase in plasma AcSDKP levels. Changes in plasma AcSDKP and in vitro ACE activity over time showed an intermittent reactivation of ACE between each captopril dose. In subjects with chronic renal failure (creatinine clearance<60 mL/min per 1.73 m2), plasma AcSDKP levels were 22 times higher (95% confidence interval, 15 to 33) in the ACEI group (n=35) than the control group (n=23); in subjects with normal renal function, they were only 4.1 times higher (95% confidence interval, 3.2 to 5.3) in the ACEI group (n=19) than the non-ACEI group (n=21). Renal failure itself led to a slight increase in plasma AcSDKP concentration. In conclusion, intermittent reactivation of ACE between doses of an ACEI is the major mechanism accounting for the lack of major AcSDKP accumulation during chronic ACE inhibition in subjects with normal renal function.

[Buerger's disease or thromboangiitis obliterans]

PURPOSE

To review clinical data, pathophysiology and treatment of thromboangiitis (Buerger's disease).

DATA SYNTHESIS

Buerger's disease or thromboangiitis obliterans (TAO) is an obliterative vascular disease that affects medium and small sized arteries as well as superficial veins. Young males and smokers are preferentially afflicted with the disease. TAO accounts for 0.5 to 5% of occlusive vascular disease. Though TAO has a world-wide distribution, it can be found with greater prevalence in Eastern Europe, the Mid-East, Asia, and Southeast Asia. Women account for 10 to 20% of the patients and 5 to 10% are more than 60-years-old. Approximately 95% are smokers and disease activity is strongly associated with the use of tobacco. The pathogenesis is poorly understood and most hypotheses are controversial. There is no specific marker of the disease and the diagnosis is based on clinical and angiographic criteria. The disease spontaneously leads to tissue loss and major amputations. This can generally be avoided by discontinuing smoking. Induced hypervolemia and prostacyclins are effective treatments of critical limb ischemia in TAO.

CONCLUSION

If pathophysiology is still poorly understood, spontaneous evolution can be avoided by stopping tobacco and prostacyclin.

Human serum does not contain a high affinity estrogen-binding glycoprotein different from sex hormone-binding globulin

The mannoglycoprotein fraction obtained by Concanavalin-A chromatography of human serum binds both androgens and estrogens with high affinity. Sex hormone-binding globulin (SHBG) is a component of this fraction that binds both steroids, but the fraction may contain another component that binds only estrogen. We used several chromatographic methods to ascertain whether the estradiol-binding properties of the mannoglycoprotein fraction could be attributed to SHBG or to SHBG and the putative estrogen-binding protein. DEAE-trisacryl, chromatofocusing, and anti-SHBG-immunoglobulin Sepharose chromatography resulted in coelution of the androgen- and estrogen-binding activities. SHBG purified by ligand affinity chromatography as well as immunoaffinity-purified SHBG had estradiol-binding properties similar to those of the crude mannoglycoprotein preparation. These data strongly suggest that 1) SHBG is the only estradiol-binding protein in the mannoglycoprotein fraction obtained by Concanavalin-A chromatography of human serum, and 2) the putative estradiol-binding protein of serum is most likely SHBG.