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Ultrasound contrast on the left side of the heart without the need for left heart catheterisation was achieved by hand injections of 8 to 10 ml 5 per cent dextrose solution through a catheter in the pulmonary wedge position. Injections were performed in 18 patients undergoing routine cardiac catheterisation and M-mode or two-dimensional echocardiography was used. An adequate wedge position was attained in 17 of the 18 patients. Nine had injections through Cournand catheters, three through Swan-Ganz catheters, and five through both. In 11 of these 17 patients left atrial or left ventricular echocardiographic contrast was seen immediately after wedge injection. Two patients showed diminished or absent contrast on later injections from the same position. Better results were obtained with the Cournand catheter (11/15 positive) than with the Swan-Ganz (1/8 positive) catheter. Pulmonary artery injections proximal to the wedge position did not cause left-sided contrast. No complications were observed. The safety of this method remains to be determined.
No abstract is provided for this article.
To describe the updated coronary computed tomographic angiography (CCTA)-based coronary artery bypass graft (CABG) anatomic SYNTAX Score (aSS) and assess its utility and reproducibility for assessing the completeness of revascularization after CABG. The CCTA-CABG aSS is a visual assessment using CCTA post-CABG which quantifies the failure in effectively grafting stenotic coronary segments, and therefore assesses the completeness of surgical revascularization. It is calculated by subtracting the aSS of successfully anastomosed coronary segments from the aSS of the native coronary tree. The inter-observer reproducibility of the CCTA-CABG aSS was evaluated in 45 consecutive patients with three-vessel disease with or without left main disease who underwent a CCTA 30 days (± 7 days) after CABG. The CCTA-CABG aSS was evaluated in 45 consecutive patients with 117 bypass grafts and 152 anastomoses. The median native coronary aSS was 35.0 [interquartile range (IQR) 27.0-41.0], whilst the median CCTA-CABG aSS was 13.0 (IQR 9.0-20.5). The inter-observer level of agreement for the native coronary aSS and the CCTA-CABG aSS were both substantial with respective Kappas of 0.67 and 0.61. The CCTA-CABG aSS was feasible in all patients who underwent CABG for complex coronary artery disease with substantial inter-observer reproducibility, and therefore can be used to quantify the completeness of revascularization after CABG.
The behavior and design of hot-rolled and cold-formed steel square and rectangular hollow section (SHS and RHS) columns, made of both normal- and high-strength material, are addressed in this paper. A series of experiments on hot-rolled high-strength steel SHS columns was first conducted—six tests on S690 SHS 100×100×4 columns and six tests on S770 SHS 120×120×6.3 columns were performed. Finite-element (FE) models were developed to replicate the experimental results and to carry out parametric studies to expand the column buckling data pool. The accuracy of the European and North American buckling design rules for normal- and high-strength steel SHS and RHS columns was evaluated through comparisons with the freshly generated test and FE results, as well as with existing test data collected from the literature. Finally, a modified approach was proposed and statistically verified in accordance with existing standards; the new approach features an imperfection factor that is a continuous function of yield strength, reflecting the reducing relative influence of residual stresses and global imperfections with increasing steel grades. Improved consistency in resistance predictions over the existing design provisions is demonstrated across a wide range of steel grades and relative slenderness values.
Emphasizing state-of-the-art pharmacological approaches to controlling pathophysiological processes in the airway, this comprehensive reference provides clinicians and scientists with a review of the normal and abnormal physiological, biochemical, and molecular aspects of the respiratory tract. The
This paper presents a comprehensive experimental study of the buckling behavior of ferritic stainless steel tubular section beam-column structural members subjected to unequal end moments. Testing was carried out on two cold-formed and seam-welded cross sections—one rectangular hollow section (RHS) 100×40×2 and one square hollow section (SHS) 60×60×3 made of grade AISI 410 (EN 1.4003) stainless steel. The experimental investigation included a series of material tensile coupon tests, initial local and global geometric imperfection measurements and 24 beam-column tests under unequal end moments. The experimental setup and procedures are described, and the test observations, including the key test results, the load-deformation histories, and the failure modes, are fully reported. The experimental results were carefully analyzed and then compared with the design strength predictions determined according to the current European code, American specification, and Australian/New Zealand standard for stainless steel structures, enabling the accuracy of each codified method to be evaluated. Generally, the European code resulted in the most conservative and scattered strength predictions among the three codified approaches, owing principally to the use of the same treatment for stainless steel beam-columns under both equal and unequal end moments. The American specification and Australian/New Zealand standard employ an equivalent uniform moment factor to consider the beneficial effects of moment gradient on beam-column strengths. These approaches were shown to offer more accurate and consistent capacity predictions for ferritic stainless steel beam-columns under unequal end moments, though further improvements remain possible.