Culprit lesions of patients, who have had an acute coronary syndrome commonly, are ruptured coronary plaques with superimposed thrombus. The precursor of such lesions is an inflamed thin-capped fibroatheroma. These plaques can be imaged by means of invasive techniques, such as intravascular ultrasound (and derived techniques), optical coherence tomography, and near-infrared spectroscopy. Often these patients exhibit similar (multiple) plaques beyond the culprit lesion. These remote plaques can be assessed noninvasively by computed tomographic angiography and MRI and also using invasive imaging. The detection of these remote plaques is not only feasible but also in natural history studies have been associated with clinical coronary events. Different systemic pharmacological treatments have been studied (mostly statins) with modest success and, therefore, newer approaches are being tested. Local treatment for such lesions is in its infancy and larger, prospective, and randomized trials are needed. This review will describe the pathological and imaging findings in culprit lesions of patients with acute coronary syndrome and the assessment of remote plaques. In addition, the pharmacological and local treatment options will be reviewed.
Non-adrenergic, non-cholinergic (NANC) neural mechanisms regulate airway tone in guinea-pigs, and it is possible that they may be regulated by other nerves. We have investigated effects of neuropeptide Y (NPY), a co-transmitter of adrenergic nerves, on the excitatory (bronchoconstrictor) NANC (e-NANC) response elicited both in vivo (via bilateral vagal nerve stimulation) and in vitro (via electrical field stimulation [EFS]), and on inhibitory (bronchodilator) NANC (i-NANC) responses in upper trachea elicited by EFS. NPY inhibited the e-NANC to vagal stimulation in vivo in a dose-dependent manner (90.0 +/- 3.4% inhibition at 500 micrograms/kg), but failed to alter the bronchoconstrictor response to exogenous substance P (SP). NPY also inhibited the e-NANC response to EFS in main and hilar bronchi (57.2 +/- 8.6% in main and 46.34 +/- 7.5% in hilar bronchi at 10(-6) M), whilst having no effect on the contractile response to SP. In contrast NPY had no effect on the i-NANC response in vitro. Thus, NPY exerts a powerful inhibitory action on tachykinin release from peripheral endings of capsaicin-sensitive airway sensory nerves, but has no effect on the i-NANC neural mechanisms. This suggests that adrenergic nerves may modulate e-NANC responses in the airways.
There are a number of scenarios in which structural members experience torsion, including under the direct application of torsional loading, when transverse loading is applied at an eccentricity to the shear centre and as a second order effect arising from lateral torsional instability. To date, the torsional rigidity of concrete-filled steel tubular (CFST) sections has yet to be fully explored; hence a study into the uniform torsional rigidity of square CFST sections is presented herein. First, the strain energy of square CFST sections is formulated, in which the longitudinal warping displacement is assumed to have an undetermined constant. The undetermined constant is then deduced by means of the principle of minimum strain energy, and thus an analytical expression for the uniform torsional rigidity of square CFST sections is obtained. The accuracy of the derived formula is verified against existing theoretical solutions for simplified scenarios, test data and the results of numerical simulations. Finally, the influence of the key parameters in the derived formula for the torsional rigidity of square CFST sections are analysed, and a simplified design formula is presented.
OBJECTIVES This study sought to establish whether the early favorable results in the Benestent-I randomized trial comparing elective Palmaz-Schatz stent implantation with balloon angioplasty in 516 patients with stable angina pectoris are maintained at 5 years. BACKGROUND The size of the required sample was based on a 40% reduction in clinical events in the stent group. Seven months and one-year follow-up in this trial showed a decreased incidence of restenosis and clinical events in patients randomized to stent implantation. METHODS Data at five years were collected by outpatient visit, via telephone and via the referring cardiologist. Three patients in the stent group and one in the percutaneous transluminal coronary angioplasty (PTCA) group were lost to follow-up at five years. Major clinical events, anginal status and use of cardiac medication were recorded according to the intention to treat principle. RESULTS No significant differences were found in anginal status and use of cardiac medication between the two groups. In the PTCA group, 27.3% of patients underwent target lesion revascularization (TLR) versus 17.2% of patients in the stent group (p = 0.008). No significant differences in mortality (5.9% vs. 3.1%), cerebrovascular accident (0.8% vs. 1.2%), myocardial infarction (9.4% vs. 6.3%) or coronary bypass surgery (11.7% vs. 9.8%) were found between the stent and PTCA groups, respectively. At five years, the event-free survival rate (59.8% vs. 65.6%; p = 0.20) between the stent and PTCA groups no longer achieved statistical significance. CONCLUSIONS The original 10% absolute difference in TLR in favor of the stent group has remained unchanged at five years, emphasizing the long-term stability of the stented target site.
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