Background Among asymptomatic patients with severe carotid artery stenosis but no recent stroke or transient cerebral ischaemia, either carotid artery stenting (CAS) or carotid endarterectomy (CEA) can restore patency and reduce long-term stroke risks. However, from recent national registry data, each option causes about 1% procedural risk of disabling stroke or death. Comparison of their long-term protective effects requires large-scale randomised evidence.Methods ACST-2 is an international multicentre randomised trial of CAS versus CEA among asymptomatic patients with severe stenosis thought to require intervention, interpreted with all other relevant trials. Patients were eligible if they had severe unilateral or bilateral carotid artery stenosis and both doctor and patient agreed that a carotid procedure should be undertaken, but they were substantially uncertain which one to choose. Patients were randomly allocated to CAS or CEA and followed up at 1 month and then annually, for a mean 5 years. Procedural events were those within 30 days of the intervention. Intention-to-treat analyses are provided. Analyses including procedural hazards use tabular methods. Analyses and meta-analyses of non-procedural strokes use Kaplan-Meier and log-rank methods. The trial is registered with the ISRCTN registry, ISRCTN21144362.

Effort thrombosis of the subclavian vein (Paget-Schroetter syndrome) has long been considered a primary thrombotic process, but recent experience suggests that it may commonly result from repeated mechanical compression. Increased awareness of the pathophysiology of this syndrome can allow timely, improved diagnostic screening and the use of specific surgical intervention to relieve the venous consequences. During the past 15 years we have treated six patients with mechanical compression in the thoracic outlet causing surgically correctable venous occlusive problems. There were four men and two women with an average age of 38 years (range 26 to 53 years). All patients exhibited pain, swelling, and cyanosis of the upper extremity, with worsening venous congestion on abduction of the arm. Five of six patients were originally treated for effort thrombosis of the subclavian vein with arm elevation and anticoagulation; two also underwent immediate thrombolytic therapy with urokinase. Venography was prompted in each case by positional symptoms during follow-up and showed irregular stenosis of the subclavian vein adjacent to the first rib. All patients underwent extended first rib resection and circumferential venolysis (one patient underwent bilateral procedures); one was performed through a transaxillary approach, two through a supraclavicular approach, and four through a new, "paraclaviculad' approach. All subclavian veins appeared normal after venolysis. Five of six patients also underwent complete scalenectomy and brachial plexus neurolysis. In each patient, venous and neurogenic symptoms resolved and venography confirmed a patent subclavian vein, with follow-up ranging from 11 months to 13 years (mean 3.8 years).

This study was designed to develop a two-dimensional echocardiographic method of measuring the mass of the left ventricle. The general formula for an ellipse was used to derive an algorithm that described the shell volume of concentric truncated ellipsoids. In 10 canine left ventricular two-dimensional echocardiograms, this algorithm accurately predicted postmortem left ventricular mass (r = .98, SEE ± 6 g) and was independent of cardiac cycle phase (systole vs diastole, r = .92). Circulation 68, No. 1, 210-216, 1983. LEFT VENTRICULAR MASS is an important descriptor of cardiac functional status. Pathologically or physiologically increased mass results from the hypertrophic process that frequently, but not always, is accompanied by increased wall thickness. Invasive and noninvasive imaging techniques such as M mode echocardiography and angiography allow quantitation of left ventricular mass by methods that rely on limited measurements of wall thickness taken from one or two loci at the cardiac base in combination with ventricular volume estimates of varying accuracy. 17Although M mode methods have been shown to have useful clinical and investigative applications,7 9 they require technically excellent septal and posterior wall imaging and are proscribed in regional myocardial disease.6 Two-dimensional echocardiography has been shown to provide noninvasive cardiac images from which left ventricular volumes can be reliably measured. IO-2 These methods are superior to M mode I A geometrically rational method of measuring mass from two-dimensional echocardiograms is desirable because it should be less vulnerable to errors arising from the extrapolation of three-dimensional information from linear measurements and from segmental disease.Our purpose was to develop and validate a twodimensional echocardiographic technique for estimating left ventricular mass in which a geometrically representative algorithm, a representative measure of wall thickness, and easily obtained internal left ventricular dimensions are used. MethodsThe study consisted of two phases. In the first phase an algorithm was derived that was both anatomiically logical and solvable with easily obtained echocardiographic dimensions; in the second phase this algorithm was tested in an animal model. Derivation of a mass algorithm. A truncated ellipsoid of revolution was used as a model for developing the algorithm because its shape closely resembles that of the left ventricle.Geiser and Bove'5 found that a similar model provided accurate left ventricular mass predictions from direct measurements of postmortem ventricular wall thickness. Figure 1 is a schematic representation of the long-and short-axis sections of the left ventricle as a truncated ellipsoid. This figure shows the locations of some of the minor-axis radii (semiminor axis) and the major-or long-axis segments (semimajor axis and truncated semimajor axis).Wall thickness was approximated from the short axis at the level of the papillary muscle tips by directly tracing and measuring t...

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SUMMARY In vivo studies were performed on 28 dogs to evaluate the usefulness of transmission computed tomography (CT) in the detection and quantitation of experimentally induced myocardial infarction. Intravenously administered contrast material was required to define the internal structure of the heart and to differentiate normal from infarcted tissue. Transmural IN VIVO computed transmission tomography (CT) adds to noninvasive cardiac imaging the capacity for high spatial resolution imaging. CT studies of myocardial infarction in vitro1-4 suggested the value of this technique in the detection and quantitation of myocardial infarcts. It was believed that with the scan times available, cardiac motion would prevent practical application.5 In this feasibility study, performed using experimentally induced myocardial infarctions in dogs, the capability of a whole-body scanner, which has a scan time of 4.8 seconds, to provide useful images was assessed. The studies were aimed at answering the following questions:(I) How early after coronary arterial ligation can infarcts be identified in vivo?(2) Must the scans be performed with contrast enhancement, and if so, is it better to deliver the contrast agent by infusion or by bolus? Materials and Methods InstrumentationThese studies were performed using a whole-body scanner (General Electric CT/T 7800) with software and hardware modifications designed to permit rapid sequence scanning and retrospective ECG gating. The data for the gated reconstructions were obtained retrospectively by selecting appropriate views from a series of scans taken with a simultaneous continuous recording of the ECG as previously described.6 lhe gating window was typically about 100 msec, arid by using a time overlapping sequence, up to 24 gated mniages per cardiac cycle could be displayed in a nonflicker cine mode similar to those obtained with gated isotope studies. Special display software permitted reformatting of the display data from a series of cojitiguous axial slices into any plane (coronal, sagittal or oblique). Image data were scaled in accord with the old Hounsfield (+ 500) scale, in which 5 units correspond to approximately 1% of the attenuation coefficient of water. Imaging and Contrast EnhancementBefore imaging, the fasting dogs were anesthetized with sodium pentobarbital (30 mg/kg), paralyzed with succinylcholine (2 mg/kg), intubated, and ventilated with a Harvard dual-phase respirator using humidified room air. The dogs were held supine in a Plexiglas cradle and placed head first in the scanner. The level of the cardiac apex was found by palpation and marked on the chest. This reference mark was used with the instrument's alignment lights to position the dog in the scanner. A series of scans was obtained without contrast medium from the apex to tne base of the heart at 1-cm intervals to confirm the position of the heart and to act as control scans. Respiration was suspended at full inspiration throughout the duration 597 by guest on