Risks and benefits of adding anti-platelet therapy to warfarin among patients with prosthetic heart valves: a meta-analysis

AbstractOBJECTIVESThe objective of this study was to compare the effectiveness and safety of adding dipyridamole or aspirin to warfarin among patients with prosthetic heart valves using meta-analytic techniques.BACKGROUNDPatients with prosthetic heart valves are at increased risk for valve thrombosis and arterial thromboembolism. Oral anticoagulation alone, or the addition of antiplatelet drugs, has been used to minimize this risk. An important issue is the effectiveness and safety of the latter strategy.METHODSA combined MEDLINE and manual search was made for relevant articles from 1966 to November 1999. Standard meta-analysis techniques were used.RESULTSTen studies involving 2,199 subjects met the inclusion criteria. Compared with anticoagulation alone, the addition of an antiplatelet agent reduced the risk of thromboembolic events (odds ratio [OR]: 0.41, p < 0.001) and total mortality (OR: 0.49, p < 0.001). The risk of major bleeding was increased when antiplatelet agents were added (OR: 1.50, p = 0.033). For major bleeding, the comparison of trials performed before and after 1990 (OR: 2.23 and 0.88, respectively) showed that the chi-square test for heterogeneity was significant (p = 0.025). The latter trials used low-dose aspirin, suggesting that the risk of bleeding may be lower with contemporary low-dose (100 mg daily) aspirin.CONCLUSIONSAdding antiplatelet therapy, especially low-dose aspirin, to warfarin decreases the risk of systemic embolism or death among patients with prosthetic heart valves. The risk of major bleeding is slightly increased with antiplatelet therapy. Nonetheless, the risk of bleeding appears to have diminished with the lower doses of aspirin used in the more recent trials, resulting in a favorable risk-to-benefit profile

Regurgitation Hemodynamics Alone Cause Mitral Valve Remodeling Characteristic of Clinical Disease States In Vitro

Mitral valve regurgitation is a challenging clinical condition that is frequent, highly varied, and poorly understood. While the causes of mitral regurgitation are multifactorial, how the hemodynamics of regurgitation impact valve tissue remodeling is an understudied phenomenon. We employed a pseudo-physiological flow loop capable of long-term organ culture to investigate the early progression of remodeling in living mitral valves placed in conditions resembling mitral valve prolapse (MVP) and functional mitral regurgitation (FMR). Valve geometry was altered to mimic the hemodynamics of controls (no changes from native geometry), MVP (5ﾠmm displacement of papillary muscles towards the annulus), and FMR (5ﾠmm apical, 5ﾠmm lateral papillary muscle displacement, 65% larger annular area). Flow measurements ensured moderate regurgitant fraction for regurgitation groups. After 1-week culture, valve tissues underwent mechanical and compositional analysis. MVP conditioned tissues were less stiff, weaker, and had elevated collagen III and glycosaminoglycans. FMR conditioned tissues were stiffer, more brittle, less extensible, and had more collagen synthesis, remodeling, and crosslinking related enzymes and proteoglycans, including decorin, matrix metalloproteinase-1, and lysyl oxidase. These models replicate clinical findings of MVP (myxomatous remodeling) and FMR (fibrotic remodeling), indicating that valve cells remodel extracellular matrix in response to altered mechanical homeostasis resulting from disease hemodynamics

Prosthetic Aortic Valve Thrombosis

Prosthetic valve thrombosis is the second leading cause of prosthetic valve deterioration and is being more readily diagnosed with the use of echocardiography and multidetector cardiac CT. Presentation of valve thrombosis can be acute or subacute and any change in clinical status of a patient with a prosthetic valve should raise a suspicion of prosthetic valve thrombosis. Diagnosis entails detailed clinical examination and comprehensive imaging. The choice of therapeutic options includes anticoagulation, fibrinolytic therapy, or valve replacement. Antiplatelet and anticoagulation therapy remain the mainstay of thrombosis prevention in patients with a prosthetic valve and a personalized approach is required to optimize prosthetic valve function and minimize the risk of bleeding

Flows and cohesion: balancing capabilities across an expanded union

The dynamics of physical relocation of intellectual capital is seen in the flow of skilled workers across international boundaries and the internal movements within the increasingly integrated economy of the European Union. This article describes a research framework developed within the context of a globalised economy and its potential application to issues within the boundaries of the European Unio

Redox-neutral organocatalytic Mitsunobu reactions

Nucleophilic substitution reactions of alcohols are amongst the most fundamental and strategically important transformations in organic chemistry. For over half a century these reactions have been achieved using stoichiometric, and often hazardous, reagents to activate the otherwise unreactive alcohols. Here we demonstrate that a specially designed phosphine oxide promotes nucleophilic substitution reactions of primary and secondary alcohols within a redoxneutral catalysis manifold that produces water as the sole by-product. The scope of the catalytic coupling process encompasses a range of acidic pronucleophiles that allow stereospecific construction of carbon-oxygen and carbon-nitrogen bonds

The Role of Echocardiography and Other Imaging Modalities in Patients With Left Ventricular Assist Devices

Recent advances in the field of left ventricular device support have led to an increased use of left ventricular assist devices (LVADs) in patients with end stage heart disease. The primary imaging modality to monitor patients with LVADs has been echocardiography. The purpose of this review is to highlight the clinical role of echo and other noninvasive imaging modalities in the assessment of cardiac structure and function in patients with pulsatile and continuous flow LVADs. In addition, we discuss the role of imaging with emphasis on echo to detect LVAD dysfunction and device related complications

Defining the genetic susceptibility to cervical neoplasia - a genome-wide association study

Funding: MAB was funded by a National Health and Medical Research Council (Australia) Senior Principal Research Fellowship. Support was also received from the Australian Cancer Research Foundation. JL holds a Tier 1 Canada Research Chair in Human Genome Epidemiology. The Seattle study was supported by the following grants: NIH, National Cancer Institute grants P01CA042792 and R01CA112512. Cervical Health Study (from which the NSW component was obtained) was funded by NHMRC Grant 387701, and CCNSW core grant. The Montreal study was funded by the Canadian Institutes of Health Research (grant MOP-42532) and sample processing was funded by the Reseau FRQS SIDA-MI. The Swedish Research Council, the Swedish Foundation for Strategic Research, the ALF/LUA research grant in Gothenburg and Umeå, the Lundberg Foundation, the Torsten and Ragnar Soderberg’s Foundation, the Novo Nordisk Foundation, and the European Commission grant HEALTH-F2-2008-201865-GEFOS, BBMRI.se, the Swedish Society of Medicine, the KempeFoundation (JCK-1021), the Medical Faculty of Umeå University, the County Council of Vasterbotten (Spjutspetsanslag VLL:159:33-2007). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscriptPeer reviewedPublisher PDFPublisher PD