Journal of thrombosis and haemostasis : JTH
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J. Thromb. Haemost. · Sep 2016
Meta AnalysisDiagnostic characteristics of lower limb venous compression ultrasonography in suspected pulmonary embolism: a meta-analysis.
Essentials Lower limb ultrasonography (CUS) could be useful in suspected pulmonary embolism (PE). We performed a metaanalysis on the diagnostic characteristics of CUS in suspected PE. With a sensitivity of 41%, proximal CUS would be positive in one of every 7.3 patients. Complete CUS has a higher sensitivity but specificity for PE is too low to use it in suspected PE. ⋯ Background Diagnosis of pulmonary embolism (PE) is commonly based on D-dimer measurement and computed tomography (CT) angiography. Lower limb vein compression ultrasonography (CUS) for diagnosing deep vein thrombosis may be of interest in patients with suspected PE. Objectives We aimed to summarize the data on the diagnostic characteristics of CUS in suspected PE patients. Patients/Methods We conducted a literature review by using PUBMED and EMBASE and included 15 prospective studies in which CUS was performed in consecutive patients with suspected PE. Results Of the 6991 included patients, 2001 (30%) had pulmonary embolism. Eight of the 15 studies included only outpatients, two included hospitalized patients and five involved both in- and outpatients. In 13 studies, only proximal CUS was performed. Two studies analyzed the added value of distal CUS including the calf veins (whole-leg CUS). Pooled estimate of proximal CUS sensitivity was 41% (95% confidence interval [CI], 36-46%) with strong heterogeneity (I square, 79%). Specificity of proximal CUS was 96% (95% CI, 94-98%). The overall positive likelihood ratio for proximal CUS was 11.9 (95% CI, 7.1-19.8), whereas the overall negative likelihood ratio was 0.6 (95% CI, 0.5-0.7). The sensitivity of whole-leg CUS was 79% (95% CI, 24-98%) and specificity was 84% (95% CI, 76-90%). Conclusions Proximal CUS has low sensitivity and cannot be used to rule out PE. Nevertheless, its high specificity allows confirming PE, which may be useful in patients with contraindications to CT angiography. Whole-leg CUS has a higher sensitivity but low specificity for PE and can therefore not be recommended.
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J. Thromb. Haemost. · Sep 2016
A rabbit model of cerebral microembolic signals for translational research: preclinical validation for aspirin and clopidogrel.
Essentials Microembolic signal (MES) is an independent predictor of stroke risk in patients. A rabbit model of cerebral microembolic signals was established. Therapeutic efficacy was demonstrated for aspirin and clopidogrel on microembolic signals. Potential translational value of this preclinical model of MES was demonstrated. ⋯ Objectives Cerebral microembolic signals (MESs) detected by transcranial Doppler (TCD) ultrasound constitute an independent predictor of stroke risk and prognosis. The aim of this study was to develop a novel preclinical model of MESs to facilitate translational research. Methods A clinical TCD ultrasound machine was used to detect MESs in the cerebral circulation of New Zealand White rabbits. Technical feasibility was assessed for the measurement of MESs in the middle cerebral artery (MCA) by TCD. FeCl3 -induced carotid arterial thrombosis was optimized for the generation of endogenous microemboli. Ascending doses of two antithrombotic agents (aspirin and clopidogrel) were evaluated individually and in combination for their effects on both arterial thrombosis and MESs in a 30% FeCl3 -induced carotid arterial thrombosis model, along with ex vivo functional assays. Results Dose-dependent FeCl3 -induced arterial thrombosis studies showed that 30% FeCl3 resulted in the most consistent and reproducible MESs in the MCA (3.3 ± 0.7 MESs h(-1) ). Ascending-dose studies showed that the effective doses for 50% inhibition (ED50 ) of thrombus formation, based on integrated blood flow and thrombus weight, respectively, were 3.1 mg kg(-1) and 4.2 mg kg(-1) orally for aspirin, and 0.3 mg kg(-1) and 0.28 mg kg(-1) orally for clopidogrel. The ED50 values for MES incidence were 12.7 mg kg(-1) orally for aspirin, and 0.25 mg kg(-1) orally for clopidogrel. Dual treatment with aspirin (5 mg kg(-1) ) and clopidogel (0.3 mg kg(-1) ) resulted in significant reductions in cerebral MESs (P < 0.05) as compared with monotherapy with either agent. Conclusions Our study demonstrated the successful establishment of the MES model in rabbits, and it may provide translational value for MESs and ischemic stroke research.