Delayed treatment for a case of acute ischaemic stroke using mechanical embolectomy - the L5 Merci Retriever

Endovascular therapies for acute ischaemic stroke represent important alternatives or adjuncts to thrombolysis. A middle-aged male suffered a Thrombolysis in Myocardial Infarction (TIMI) Grade 0 distal left middle cerebral artery (LMCA) occlusion resulting in right hemiparesis and dysphasia. Intravenous thrombolysis was contraindicated due to pre-existing anticoagulant therapy and associated risk of intracranial haemorrhage. The patient underwent rescue mechanical embolectomy with an L5 Merci Retriever, with adjuvant local intra-arterial (IA) thrombolysis. Successful TIMI Grade 3 restoration of LMCA blood flow occurred within eight hours of ictus. Aphasia resolved within 24 hours, whilst other motor and speech symptoms gradually improved over 6 months, allowing the patient to resume work and independent living. Mechanical embolectomy appears to be a safe and effective alternative in cases of delayed presentation, or where intravenous thrombolysis is contraindicated. Combined mechanical embolectomy and adjuvant IA thrombolysis, instituted within eight hours of ictus in an anticoagulated patient, achieved favourable clinical outcome (modified Rankin Score of 2) without major thromboembolic or haemorrhagic complications

Structural member behaviour and analysis in case of fire

peer reviewe

The prognostic utility of tests of platelet function for the detection of ‘aspirin resistance’ in patients with established cardiovascular or cerebrovascular disease : a systematic review and economic evaluation

Background: The use of aspirin is well established for secondary prevention of cardiovascular disease. However, a proportion of patients suffer repeat cardiovascular events despite being prescribed aspirin treatment. It is uncertain whether or not this is due to an inherent inability of aspirin to sufficiently modify platelet activity. This report aims to investigate whether or not insufficient platelet function inhibition by aspirin (‘aspirin resistance‘), as defined using platelet function tests (PFTs), is linked to the occurrence of adverse clinical outcomes, and further, whether or not patients at risk of future adverse clinical events can be identified through PFTs. Objectives: To review systematically the clinical effectiveness and cost-effectiveness evidence regarding the association between PFT designation of ‘aspirin resistance’ and the risk of adverse clinical outcome(s) in patients prescribed aspirin therapy. To undertake exploratory model-based cost-effectiveness analysis on the use of PFTs. Data sources: Bibliographic databases (e.g. MEDLINE from inception and EMBASE from 1980), conference proceedings and ongoing trial registries up to April 2012. Methods: Standard systematic review methods were used for identifying clinical and cost studies. A risk-of-bias assessment tool was adapted from checklists for prognostic and diagnostic studies. (Un)adjusted odds and hazard ratios for the association between ‘aspirin resistance’, for different PFTs, and clinical outcomes are presented; however, heterogeneity between studies precluded pooling of results. A speculative economic model of a PFT and change of therapy strategy was developed. Results: One hundred and eight relevant studies using a variety of PFTs, 58 in patients on aspirin monotherapy, were analysed in detail. Results indicated that some PFTs may have some prognostic utility, i.e. a trend for more clinical events to be associated with groups classified as ‘aspirin resistant’. Methodological and clinical heterogeneity prevented a quantitative summary of prognostic effect. Study-level effect sizes were generally small and absolute outcome risk was not substantially different between ‘aspirin resistant’ and ‘aspirin sensitive’ designations. No studies on the cost-effectiveness of PFTs for ‘aspirin resistance’ were identified. Based on assumptions of PFTs being able to accurately identify patients at high risk of clinical events and such patients benefiting from treatment modification, the economic model found that a test–treat strategy was likely to be cost-effective. However, neither assumption is currently evidence based. Limitations: Poor or incomplete reporting of studies suggests a potentially large volume of inaccessible data. Analyses were confined to studies on patients prescribed aspirin as sole antiplatelet therapy at the time of PFT. Clinical and methodological heterogeneity across studies precluded meta-analysis. Given the lack of robust data the economic modelling was speculative. Conclusions: Although evidence indicates that some PFTs may have some prognostic value, methodological and clinical heterogeneity between studies and different approaches to analyses create confusion and inconsistency in prognostic results, and prevented a quantitative summary of their prognostic effect. Protocol-driven and adequately powered primary studies are needed, using standardised methods of measurements to evaluate the prognostic ability of each test in the same population(s), and ideally presenting individual patient data. For any PFT to inform individual risk prediction, it will likely need to be considered in combination with other prognostic factors, within a prognostic model