A site to transform Pubmed publications into these bibliographic reference formats: ADS, BibTeX, EndNote, ISI used by the Web of Knowledge, RIS, MEDLINE, Microsoft's Word 2007 XML.

Simon W Davies - Top 30 Publications

Prevalence and Prognostic Significance of Right Ventricular Systolic Dysfunction in Patients Undergoing Transcatheter Aortic Valve Implantation.

Cardiovascular magnetic resonance (CMR) can provide important structural information in patients undergoing transcatheter aortic valve implantation. Although CMR is considered the standard of reference for measuring ventricular volumes and mass, the relationship between CMR findings of right ventricular (RV) function and outcomes after transcatheter aortic valve implantation has not previously been reported.

Unsuspected large left ventricular pseudoaneurysm: rapid bedside diagnosis by contrast-enhanced echocardiography.

Management of concomitant coronary artery disease in patients undergoing transcatheter aortic valve implantation: the United Kingdom TAVI Registry.

The management and impact of concomitant coronary artery disease in patients referred for TAVI remains contentious. We describe the prevalence, clinical impact and management of coronary artery disease (CAD) in patients in the United Kingdom TAVI Registry.

Clinical and economic consequences of non-cardiac incidental findings detected on cardiovascular computed tomography performed prior to transcatheter aortic valve implantation (TAVI).

Transcatheter aortic valve implantation (TAVI) is an effective treatment option for patients with severe degenerative aortic valve stenosis who are high risk for conventional surgery. Computed tomography (CT) performed prior to TAVI can detect pathologies that could influence outcomes following the procedure, however the incidence, cost, and clinical impact of incidental findings has not previously been investigated. 279 patients underwent CT; 188 subsequently had TAVI and 91 were declined. Incidental findings were classified as clinically significant (requiring treatment), indeterminate (requiring further assessment), or clinically insignificant. The primary outcome measure was all-cause mortality up to 3 years. Costs incurred by additional investigations resultant to incidental findings were estimated using the UK Department of Health Payment Tariff. Incidental findings were common in both the TAVI and medical therapy cohorts (54.8 vs. 70.3%; P = 0.014). Subsequently, 45 extra investigations were recommended for the TAVI cohort, at an overall average cost of £32.69 per TAVI patient. In a univariate model, survival was significantly associated with the presence of a clinically significant or indeterminate finding (HR 1.61; P = 0.021). However, on multivariate analysis outcomes after TAVI were not influenced by any category of incidental finding. Incidental findings are common on CT scans performed prior to TAVI. However, the total cost involved in investigating these findings is low, and incidental findings do not independently identify patients with poorer outcomes after TAVI. The discovery of an incidental finding on CT should not necessarily influence or delay the decision to perform TAVI.

Reversal of dilated cardiomyopathy after glucagonoma excision.

Long-term outcomes after transcatheter aortic valve implantation in high-risk patients with severe aortic stenosis: the U.K. TAVI (United Kingdom Transcatheter Aortic Valve Implantation) Registry.

The objective was to define the characteristics of a real-world patient population treated with transcatheter aortic valve implantation (TAVI), regardless of technology or access route, and to evaluate their clinical outcome over the mid to long term.

Transcatheter aortic valve implantation in degenerate failing aortic homograft root replacements.

Defining the appropriate CTA stenosis threshold for gatekeeping to invasive angiography: 50% or 70%?

There is currently much debate around the limited positive predictive value (PPV) of CT coronary angiography (CTA). There remain no published studies comparing different thresholds to define significant visual stenoses on CTA compared to the gold standard quantitative coronary angiography (QCA). The spatial resolution for ICA is (0.1 mm)(3) compared with (0.5 mm)(3) in clinical CTA and direct comparison introduces a systematic overestimation of stenosis severity by CTCA. Assessing both ≥ 50% and ≥ 70% visual stenoses on CTA with QCA we found that the negative predictive value (NPV) of CTA is equally high for both. The PPV of CTA improves using ≥ 70% but with a loss of sensitivity. Using ≥ 70% stenosis on CTA for referral for ICA would reduce the number of ICA that does not lead to percutaneous intervention (PCI) but a functional test for intermediate lesions (visual stenoses of 50%-69%) on CTA is recommended to overcome the reduction in sensitivity.

Transcatheter aortic valve intervention through the axillary artery for the treatment of severe aortic stenosis.

The role of cardiovascular magnetic resonance in patients presenting with chest pain, raised troponin, and unobstructed coronary arteries.

Troponin measurement is used in the assessment and risk stratification of patients presenting acutely with chest pain when the main cause of elevation is coronary artery disease. However, some patients have no coronary obstruction on angiography, leading to diagnostic uncertainty. We evaluated the incremental diagnostic value of cardiovascular magnetic resonance (CMR) in these patients.

64-multislice computed tomography in consecutive patients with suspected or proven coronary artery disease: initial single center experience.

The improved accuracy of 64-multislice CT (MSCT) suggests that this technique may replace other non-invasive methods to detect clinically significant coronary atherosclerosis. The aim of the present study was to assess the clinical usefulness of in consecutive patients with suspected or proven coronary artery disease (CAD).

Two novel missense mutations in ABCA1 result in altered trafficking and cause severe autosomal recessive HDL deficiency.

Extremely low concentrations of high density lipoprotein (HDL)-cholesterol and apolipoprotein (apo) AI are features of Tangier disease caused by autosomal recessive mutations in ATP-binding cassette transporter A1 (ABCA1). Less deleterious, but dominantly inherited mutations cause HDL deficiency. We investigated causes of severe HDL deficiency in a 42-year-old female with progressive coronary disease. ApoAI-mediated efflux of cholesterol from the proband's fibroblasts was less than 10% of normal and nucleotide sequencing revealed inheritance of two novel mutations in ABCAI, V1704D and L1379F. ABCA1 mRNA was approximately 3-fold higher in the proband's cells than in control cells; preincubation with cholesterol increased it 5-fold in control and 8-fold in the proband's cells, but similar amounts of ABCA1 protein were present in control and mutant cells. When transiently transfected into HEK293 cells, confocal microscopy revealed that both mutant proteins were retained in the endoplasmic reticulum, while wild-type ABCA1 was located at the plasma membrane. Severe HDL deficiency in the proband was caused by two novel autosomal recessive mutations in ABCA1, one (V1704D) predicted to lie in a transmembrane segment and the other (L1379F) in a large extracellular loop. Both mutations prevent normal trafficking of ABCA1, thereby explaining their inability to mediate apoA1-dependent lipid efflux.

Combined coronary and perfusion cardiovascular magnetic resonance for the assessment of coronary artery stenosis.

The purpose of this study was to evaluate the feasibility and accuracy of combined coronary and perfusion cardiovascular magnetic resonance (CMR) in the assessment of coronary artery stenosis. Thirty-five consecutive patients (27 men, eight women, age range 34-81 years), undergoing cardiac catheterization, were assessed with 3D coronary CMR and rest-stress perfusion CMR. Significant coronary stenosis was determined by vessel narrowing or signal loss with coronary CMR, and by abnormal contrast enhancement with perfusion CMR. Coronary artery diameter stenosis greater than 50% was considered significant with conventional cardiac catheterization. Seventeen patients had significant coronary artery disease, and in these there were 35 significant stenoses on cardiac catheterization. All left main stem arteries were normal on both cardiac catheterization and coronary CMR. For the diagnosis of coronary artery stenosis, coronary CMR had a sensitivity of 92% for the left anterior descending artery (LAD), 79% for the right coronary artery (RCA), but only 13% for the circumflex coronary artery (LCX). Perfusion CMR had corresponding sensitivities of 69%, 86%, and 63%, respectively. For all arteries the accuracies for coronary and perfusion CMR were 67% and 72%, respectively. Combining coronary and perfusion CMR improved the accuracy to 77%. These data demonstrate that in patients with suspected coronary artery disease, combined coronary and perfusion CMR is feasible, increases the accuracy of detection of significant coronary stenosis, and offers the possibility of combined anatomical and hemodynamic assessment of coronary artery stenosis.

Abciximab is rapidly effective in preventing and arresting established platelet aggregation.

Abciximab reduces the thrombotic complications of angioplasty. It is also used, as a 'bail out' treatment when angioplasty is complicated by thrombus but its speed of action is not known. This study sought to establish how quickly abciximab blocks the aggregation of both quiescent and activated platelets to explain this rapid efficacy.