6,963 publications from this institution
BACKGROUND. Ketanserin is a serotonin S2-receptor antagonist that inhibits the platelet activation and vasoconstriction induced by serotonin and also inhibits the mitogenic effect of serotonin on vascular smooth muscle cells. METHODS AND RESULTS. We conducted a randomized, double blind, placebo-controlled trial to assess the effect of ketanserin in restenosis prevention after percutaneous transluminal coronary angioplasty (PTCA). Patients received either ketanserin (loading dose, 40 mg 1 hour before PTCA; maintenance dose, 40 mg bid for 6 months) or matched placebo. In addition, all patients received aspirin for 6 months. Coronary angiograms before PTCA, after PTCA, and at 6 months were quantitatively analyzed. Six hundred fifty-eight patients were entered into the intention-to-treat analysis. The primary clinical end point of the study was the occurrence between PTCA and 6 months of any one of the following: cardiac death, myocardial infarction, the need for repeat angioplasty, or bypass surgery. It also included the need for revascularization actuated by findings at 6-month follow-up angiography. The primary clinical end point was reached by 92 (28%) patients in the ketanserin group and 104 (32%) in the placebo group (RR, 0.89; 95% CI, 0.70, 1.13; P = .38). Quantitative angiography after PTCA and at follow-up was available in 592 patients (ketanserin, 287; control, 305). The mean difference in minimal lumen diameter between post-PTCA and follow-up angiogram (primary angiographic end point) was 0.27 +/- 0.49 mm in the ketanserin group and 0.24 +/- 0.52 mm in the control group (difference, 0.03 mm; 95% CI, -0.05, 0.11; P = .50). CONCLUSIONS. Ketanserin at the dose administered in this trial failed to reduce the loss in minimal lumen diameter during follow-up after PTCA and did not significantly improve the clinical outcome.
In fire scenarios, concrete-filled stainless steel tubular (CFSST) columns undergo initial loading at ambient temperature, loading during the heating phase as the fire develops, loading during the cooling phase as the fire dies out and continual loading after the fire. CFSST columns may fail some points during this process under combined fire and loading. In this paper, the failure modes and corresponding working mechanism of CFSST columns subjected to an entire loading and fire history are investigated. Sequentially coupled thermal-stress analyses in ABAQUS are employed to establish the temperature field and structural response of the CFSST column. To improve the precision of the finite element (FE) model, the influence of moisture on the thermal conductivity and specific heat of concrete during both the heating and cooling phases is considered using subroutines. Existing fire and post-fire test data of CFSST columns are used to validate the FE models. Comparisons between predicted and test results confirm that the accuracy of the FE models is acceptable; the FE models are then extended to simulate a typical CFSST column subjected to the entire loading and fire history. The behaviour of the CFSST column is explained by analysis of the temperature distribution, load versus axial deformation curves and failure response.
Abstract In this paper, the flexural‐torsional buckling response of austenitic stainless steel I‐section beam‐columns is investigated. Finite element simulations are performed with the aim of analysing the parameters affecting the behaviour of the studied members. The accuracy and safety of the existing design provisions of the European structural stainless steel design standard EN 1993‐1‐4 (2015) are assessed. A new method providing more accurate ultimate resistance predictions for austenitic stainless steel I‐section beam‐columns undergoing flexural‐torsional buckling is put forward. The higher accuracy, safety and reliability of the proposed design rules relative to EN 1993‐1‐4 (2015) are demonstrated and the new proposals have now been included in the revised Eurocode – prEN 1993‐1‐4 (2021).
Aims To investigate geographic disparity in long-term mortality following revascularization in patients with complex coronary artery disease (CAD). Methods and results The SYNTAXES trial randomized 1800 patients with three-vessel and/or left main CAD to percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) and assessed their survival at 10 years. Patients were stratified according to the region of recruitment: North America (N-A, n = 245), Eastern Europe (E-E, n = 189), Northern Europe (N-E, n = 425), Southern Europe (S-E, n = 263), and Western Europe (W-E, n = 678), which also served as the reference group. Compared to W-E, patients were younger in E-E (62 vs 65 years, p < 0.001), and less frequently male in N-A (65.3% vs 79.6%, p < 0.001). Diabetes (16.0% vs 25.4%, p < 0.001) and peripheral vascular disease (6.8% vs 10.9%, p = 0.025) were less frequent in N-E than W-E. Ejection fraction was highest in W-E (62% vs 56%, p < 0.001). Compared to W-E, the mean anatomic SYNTAX score was higher in S-E (29 vs 31, p = 0.008) and lower in N-A (26, p < 0.001). Crude ten-year mortality was similar in N-A (31.6%), and W-E (30.7%), and significantly lower in E-E (22.5%, p = 0.041), N-E (21.9%, p = 0.003) and S-E (22.0%, p = 0.014). Compared to W-E, adjusted mortality in N-E (HR 0.85, p = 0.019) and S-E (HR 0.72, p = 0.043) remain significantly lower after adjustment for pre- and peri-procedural factors, but no significant interaction (Pinteraction = 0.728) between region and modality of revascularization was seen. Conclusion In the era of globalization, knowledge, and understanding of geographic disparity are of paramount importance for the correct interpretation of global studies.
Objective: To investigate the accuracy and interobserver variability of Quantitative videodensitometric assessment of Mitral Regurgitation (QMR) after mitral valve replacement in a preclinical ovine model.Background: Quantitative videodensitometric aortography using the time-density principle is a well-documented technique for assessment of aortic regurgitation following transcatheter aortic valve replacement, but angiographic assessment of mitral regurgitation remains at best semi-quantitative (Sellers classification) and operator dependent.Methods: Fourteen sheep underwent surgical mitral valve replacement and were followed-up up to 1 year. A tricuspid valve with endogenous tissue restoration technology - the Xeltis valve (Xeltis BV, Eindhoven, the Netherlands) was implanted in 9 animals and the Trifecta valve (St. Jude Medical, St. Paul, MN, USA) was implanted in 5 animals. At the end of the follow-up period, the animals underwent a cardiac catheterization to measure their cardiac output and transmitral gradients immediately followed by ventriculography for QMR, then the animals were euthanatized, and the valve and peri-valvular tissue were excised. A mock-circulation (HDT-500 Hydrodynamic Test System [BDC Laboratory, US]) was used to assess the ex-vivo regurgitation fraction at a cardiac output comparable to the measurement obtained in-vivo. The CAAS A-valve 2.0.2 (Pie Medical Imaging BV, Maastricht, the Netherlands) was used for assessment of QMR. The QMR values (ex-vivo or in-vivo) as well as interobserver agreements were quantified after one, two, three, and four heart cycles.Results: The in-vivo QMR had significant correlations with the ex-vivo regurgitation fraction in all the cardiac cycles (best correlation: after 3 beats R2=0.784; p=0.002). The interobserver validation analysis showed significant agreements for all individual cardiac cycle (best agreement: after 4 beats R2=0.907; p<0.001).Conclusions: Angiographic quantification of mitral regurgitation using the CAAS-A valve prototype software is feasible, accurate, and highly reproducible in a preclinical setting. Further studies are necessary to establish the clinical value of this software.