1,721,156 research outputs found
Transcatheter aortic valve implantation: the state of play
No full textAortic stenosis is the most commonly acquired valvular heart disease in the Western world. Surgical aortic valve replacement is currently the gold-standard treatment for patients with severe symptomatic aortic stenosis. Without surgery, the prognosis is extremely poor, with a 3-year survival rate of less than 30%. Transcatheter aortic valve implantation (TAVI) is a rapidly evolving novel technique that was first introduced in 2002 and is currently available in Europe as an alternative to conventional aortic valve replacement for patients with severe symptomatic aortic stenosis who are deemed to be at too high a risk for open heart surgery. This article describes the TAVI technique and patient selection criteria. We explore how far we have come with advances in TAVI and analyze the short- and medium-term outcome data reported on TAVI so far. We will also look at the potential future role of TAVI and the challenges involved in setting up a TAVI servic
Is there evidence for prognostic benefit following PCI in stable patients? COURAGE and its implications: an interventionalist's view.
No full textThe COURAGE study has stimulated intensive discussion about the optimal approach to treatment of patients with stable angina. To some, the study implied that PCI has no clinical benefit versus optimal medical therapy but this is open to alternative considered interpretation. To the interventionalist who deploys optimal medical therapy responsibly, the study highlights the importance of the concept of an ischaemia driven approach. The availability of the pressure wire has provided cardiologists with an important additional tool with which to tailor the delivery of revascularisation to not just the ischaemic patient but also to the ischaemic lesion. Such a strategy applied to COURAGE (and perhaps also to SYNTAX) might provide a very different comparative outcome
Monitoring the effectiveness of antiplatelet therapy: opportunities and limitations
No full textPrevious clinical studies have shown heterogeneity in individual patient responses to antiplatelet therapy and high residual platelet reactivity is associated with increased risk of adverse clinical events. Monitoring response to antiplatelet therapy and tailoring treatment accordingly is currently not recommended in routine clinical practice largely due to the lack of a standardized definition of antiplatelet therapy hyporesponse and the need for a widely accepted point-of-care platelet function test that can be reliably utilized in frontline clinical practice. Recent data have shown that titrating the dose of clopidogrel in patients undergoing percutaneous coronary intervention significantly reduces the incidence of major adverse cardiovascular events and large-scale clinical trials are currently underway to investigate whether individually tailored treatment based on results of platelet function testing leads to improved clinical outcome. Furthermore, genetic testing has demonstrated a link between CYP2C19 genetic polymorphisms, altered clopidogrel metabolite concentrations and adverse clinical events. Clinical studies are currently underway to investigate the potential clinical benefit associated with genotype-guided tailoring of antiplatelet therapy. With the advent of newer, more potent antiplatelet agents and their associated increased bleeding risks, it will become imperative in the future to select the most appropriate, safe and effective drug
Thrombosis in cardiovascular disease
No full textLecture Notes: Cardiology is a comprehensive introduction to one of the most rapidly changing specialities in clinical medicine. This informative and highly accessible book presents clinical cardiology in a way that relates disease to underlying pathophysiological mechanisms, and links this directly to the patient, their disease and its management
A randomized crossover study comparing the antiplatelet effect of plavix versus generic clopidogrel
No full textBackground: Clopidogrel exists in different salt formulations. All published data that have demonstrated its beneficial effect are based entirely on the hydrogen sulphate salt contained in the branded product Plavix, which had US sales of $6.1 billion in 2010 alone. A number of cheaper generic versions of clopidogrel are increasingly being used in Europe as an alternative to Plavix, mainly for cost reasons. However, there is insufficient evidence to show that their pharmacodynamic effect is equivalent to Plavix.Methods: This prospective study investigated whether there is any significant difference in the antiplatelet effect of Plavix versus generic clopidogrel hydrochloride in healthy male volunteers. All participants received loading and maintenance doses of both drugs, in a crossover manner, separated by a 2-week washout period. Adenosine diphosphate (ADP)-induced platelet reactivity was measured using short thrombelastography at multiple timepoints.Results: The results showed interindividual heterogeneity in responses to clopidogrel but no significant difference in ADP-induced platelet reactivity between Plavix versus generic clopidogrel hydrochloride.Conclusions: Our findings suggest comparable inhibition of ADP-induced platelet reactivity with Plavix and generic clopidogrel hydrochloride. This observation is particularly pertinent at a time when the patent for Plavix is expected to expire in the near future leading to the large-scale switch to cheaper generic preparations.<br/
Nonalcoholic fatty liver disease and vascular risk
No full textPURPOSE OF REVIEW: Nonalcoholic fatty liver disease (NAFLD) is an increasingly common condition, which is strongly associated with obesity and diabetes. The risk of cardiovascular disease is increased in NAFLD and represents the main cause of death in these patients. However, given the shared features between NAFLD, the metabolic syndrome and traditional cardiovascular risk factors, uncertainty exists as to whether NAFLD is an independent risk factor for increased cardiovascular disease.RECENT FINDINGS: Multiple epidemiological and case-control studies now demonstrate that NAFLD is associated with increased vascular risk, independently of conventional cardiometabolic risk factors. Evidence also suggests a graded association between NAFLD severity and increased vascular risk. However, given the heterogeneous disease spectrum of NAFLD, these findings have limitations with respect to accuracy of diagnosis and staging of NAFLD in most studies.SUMMARY: Although accumulating evidence points to NAFLD emerging as a novel cardiovascular risk factor, more research is needed to find suitable noninvasive biomarkers of NAFLD severity to allow better risk-stratification based on cardiovascular outcomes. Furthermore, with no established pharmacological treatment option for NAFLD currently available, any potential treatment must show efficacy not only in slowing liver disease progression, but also in ameliorating adverse cardiovascular outcomes.<br/
Assessing the impact of including leaflets in the simulation of TAVI deployment in to a patient specific aortic root.
No full textComputational simulation of transcatheter aortic valve implantation (TAVI) device deployment presents a significant challenge over and above similar simulations for percutaneous coronary intervention due to the presence of prosthetic leaflets. In light of the complexity of these leaflets, simulations have been performed to assess the effect of including the leaflets in a complete model of a balloon-expandable TAVI device when deployed in a patient-specific aortic root. Using an average model discrepancy metric, the average frame positions (with and without the leaflets) are shown to vary by 0.236% of the expanded frame diameter (26 mm). This relatively small discrepancy leads to the conclusion that for a broad range of replacement valve studies, including new frame configurations and designs, patient-specific assessment of apposition, paravalvular leakage and tissue stress, modelling of the prosthetic leaflets is likely to have a marginal effect on the result
Simulation of longitudinal stent deformation in a patient-specific coronary artery
No full textIn percutaneous coronary intervention (PCI), stent malapposition is a common complication often leading to stent thrombosis (ST). More recently, it has also been associated with longitudinal stent deformation (LSD) normally occurring through contact of a post balloon catheter tip and the protruding malapposed stent struts.The aim of this study was to assess the longitudinal integrity of first and second generation drug eluting stents in a patient specific coronary artery segment and to compare the range of variation of applied loads with those reported elsewhere. We successfully validated computational models of three drug-eluting stent designs when assessed for longitudinal deformation. We then reconstructed a patient specific stenosed right coronary artery segment by fusing angiographic and intravascular ultrasound (IVUS) images from a real case. Within this model the mechanical behaviour of the same stents along with a modified device was compared. Specifically, after the deployment of each device, a compressive point load of 0.3 N was applied on the most malapposed strut proximally to the models. Results indicate that predicted stent longitudinal strength (i) is significantly different between the stent platforms in a manner consistent with physical testing in a laboratory environment, (ii) shows a smaller range of variation for simulations of in vivo performance relative to models of in vitro experiments, and (iii) the modified stent design demonstrated considerably higher longitudinal integrity. Interestingly, stent longitudinal stability may differ drastically after a localised in vivo force compared to a distributed in vitro force
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