Computed tomography versus exercise electrocardiography in patients with stable chest complaints: real-world experiences from a fast-track chest pain clinic.

OBJECTIVE: To compare the diagnostic performance of CT angiography (CTA) and exercise electrocardiography (XECG) in a symptomatic population with a low-intermediate prevalence of coronary artery disease (CAD). DESIGN: Prospective registry. SETTING: Tertiary university hospital. PATIENTS: 471 consecutive ambulatory patients with stable chest pain complaints, mean (SD) age 56 (10), female 227 (48%), pre-test probability for significant CAD >5%. INTERVENTION: All patients were intended to undergo both 64-slice, dual-source CTA and an XECG. Clinically driven quantitative catheter angiography was performed in 98 patients. MAIN OUTCOME MEASURES: Feasibility and interpretability of, and association between, CTA and XECG, and their diagnostic performance with invasive coronary angiography as reference. RESULTS: CTA and XECG could not be performed in 16 (3.4%) vs 48 (10.2%, p<0.001), and produced non-diagnostic results in 3 (0.7%) vs 140 (33%, p<0.001). CTA showed > or =1 coronary stenosis (> or =50%) in 140 patients (30%), XECG was abnormal in 93 patients (33%). Results by CTA and XECG matched for 185 patients (68%, p = 0.63). Catheter angiography showed obstructive CAD in 57/98 patients (58%). Sensitivity, specificity, positive and negative predictive value of CTA to identify patients with > or =50% stenosis was 96%, 37%, 67% and 88%, respectively; compared with XECG: 71%, 76%, 80% and 66%, respectively. Quantitative CTA slightly overestimated diameter stenosis: 6 (21)% (R = 0.71), compared with QCA. Of the 312 patients (66%) with a negative CTA, 44 (14%) had a positive XECG, but only 2/17 who underwent catheter angiography had significant CAD. CONCLUSION: CTA is feasible and diagnostic in more patients than XECG. For interpretable studies, CTA has a higher sensitivity, but lower specificity for detection of CAD.

Coronary restenosis elimination with a sirolimus eluting stent: first European human experience with 6-month angiographic and intravascular ultrasonic follow-up.

AIMS: Coronary stenting is limited by a 10%-60% restenosis rate due to neointimal hyperplasia. Sirolimus is a macrocyclic lactone agent that interacts with cell-cycle regulating proteins and inhibits cell division between phases G1 and S1. The hypothesis tested in this study is that local delivery of sirolimus with an eluting stent can prevent restenosis. METHODS AND RESULTS: Fifteen patients were treated with 18 mm sirolimus eluting BX VELOCITY stents. Quantitative angiography and three-dimensional quantitative intravascular ultrasound were performed at implantation and at the 6 months follow-up. All stent implantations were successful. One patient died on day 2, of cerebral haemorrhage and one patient suffered a subacute stent occlusion due to edge dissection (re-PTCA, CKMB 42). At 9 months no further adverse events had occurred and all patients were angina free. Quantitative coronary angiography revealed no change in minimal lumen diameter and percent diameter stenosis and hence no in-lesion or in-stent restenosis. Quantitative intravascular ultrasound showed that intimal hyperplasia volume and percent obstruction volume at follow-up were negligible at 5.3 mm(3)and 1.8%, respectively. No edge effect was observed in the segments proximal and distal to the stents. CONCLUSION: Implantation of a sirolimus-eluting stent seems to effectively prevent intimal hyperplasia.

Real-time quantification and display of skin radiation during coronary angiography and intervention.

BACKGROUND: Radiographically guided investigations may be associated with excessive radiation exposure, which may cause skin injuries. The purpose of this study was to develop and test a system that measures in real time the dose applied to each 1-cm(2) area of skin, taking into account the movement of the x-ray source and changes in the beam characteristics. The goal of such a system is to help prevent high doses that might cause skin injury. METHODS AND RESULTS: The entrance point, beam size, and dose at the skin of the patient were calculated by use of the geometrical settings of gantry, investigation table, and x-ray beam and an ionization chamber. The data are displayed graphically. Three hundred twenty-two sequential cardiac investigations in adult patients were analyzed. The mean peak entrance dose per investigation was 0.475 Gy to a mean skin area of 8.2 cm(2). The cumulative KERMA-area product per investigation was 52.2 Gy/cm(2) (25.4 to 99.2 Gy/cm(2)), and the mean entrance beam size at the skin was 49.2 cm(2). Twenty-eight percent of the patients (90/322) received a maximum dose of <1 Gy to a small skin area ( approximately 6 cm(2)), and 13.5% of the patients (42/322) received a maximum dose of >2 Gy. CONCLUSIONS: Monitoring of the dose distribution at the skin will alert the operator to the development of high-dose areas; by use of other gantry settings with nonoverlapping entrance fields, different generator settings, and extra collimation, skin lesion can be avoided.

Usefulness of three-dimensional transesophageal echocardiographic imaging for evaluating narrowing in the coronary arteries.

Coronary artery (CA) imaging has relied on invasive techniques for diagnosing stenotic lesions. Two-dimensional techniques are limited in obtaining optimal longitudinal views of all segments of the CA because of their spatial orientations. Three-dimensional echocardiography (3DE) may produce any desired cross-sectional views and reconstruct 3-dimensional images from a volumetric data set. Its role in CA imaging has not been fully explored. The aim of this study was to evaluate the potential of 3DE in visualizing CAs and in assessing the severity of stenosis. We performed transesophageal 3DE in 46 patients. Images were collected sequentially with the transducer rotated through 180 degrees. From the 3DE data sets of all 46 patients, cross-sectional views and 3-dimensional images of CAs were reconstructed. For segment-by-segment comparison between CA angiography and 3DE in semiquantitative analysis of coronary stenosis, 5 segments were defined for the proximal CA tree in 20 patients who underwent both procedures. The left main, anterior descending, circumflex, and right CAs were visualized from 3DE in 100%, 100%, 98%, and 72%. The available lengths of these segments from 3DE were 12+/-4 mm (range 4 to 22), 15+/-6 mm (range 6 to 36), 30+/-12 mm (range 13 to 60), and 18+/-9 mm (range 6 to 36), respectively. Comparison between 3DE and CA angiography in semiquantitative estimation of CA stenosis resulted in complete agreement in 83% of the segments (kappa value = 0.7). The sensitivity and specificity of 3DE in detecting significant stenosis (> or =50%) were 84% and 97%. In conclusion, transesophageal 3DE allows imaging of the proximal CA, detection of stenotic lesions, and estimation of the severity of stenosis.

[Electron-beam computed tomography: preliminary experiences in the Netherlands]. / Elektronenbundeltomografie: eerste ervaringen in Nederland.

The difference between computer tomography (CT) and electron beam tomography (EBT) is that for CT the x-ray tube rotates in a ring round the patient, and for EBT the x-ray beam rotates itself. As a result, with EBT the speed of making images is not limited by the mechanical rotation of the tube, and 16 images can be made per second. An EBT scan of a whole thorax takes 9 seconds. Specific application areas are fast moving organs and patients who cannot remain in one position for long, e.g. children and intensive care patients. Research is being conducted into the possibilities of this non-invasive technique for the demonstration of coronary artery lesions, pulmonary embolism, pulmonary metastases and dynamic examination of the major respiratory tract. Costs of an EBT scan currently amount to Dfl. 450.--but they will probably decrease as this imaging system is developed further. The exposure to radiation is about the same as that caused by a (spiral) CT.

Evaluation of transthoracic countershock with initial energy levels up to 200 J in a coronary care unit.

In a five year prospective study, transthoracic countershock of patients in the coronary care unit was evaluated with respect to efficacy, transthoracic resistance and arrhythmias. Those patients dying within 12 hours of the recorded event are referred to as agonal patients. Atrial arrhythmias were generally first treated with quinidine or disopyramide and/or a digitalis preparation. Patients with coronary heart disease were treated with lidocaine, disopyramide, or verapamil when there was time for appropriate diagnosis. The efficacy of the first shock with an energy level between 50 J and 200 J in non-agonal patients was: for atrial fibrillation, 44% (N = 34), and between 83% and 93% for tachycardias and ventricular fibrillation. The cumulative efficacy of two shocks with energy levels between 50 J and 200 J was: in atrial fibrillation 53% and others between 90% and 96%. In agonal patients with ventricular fibrillation and acute myocardial infarction the efficacy of one shock of 100-150 J was 39% and two shocks of 100-200 J, 69% (N = 13). No correlation was found between the transthoracic resistance and parameters such as body-weight, length or thorax-circumference, indicating that these should not be taken into account in the choice of the energy level for countershock. In non-agonal patients without coronary heart disease arrhythmias due to countershock increased in duration when the energy of the countershock increased (p less than 0.01, N = 39). It is concluded that the initial stored energy for defibrillation and cardioversion of nonagonal patients in a coronary care unit may be limited to 200 J (160 J delivered energy), even with atrial fibrillation after drug therapy in which case an initial energy level of 200 J seems more appropriate.

Predictive value of early maximal exercise test and thallium scintigraphy after successful percutaneous transluminal coronary angioplasty.

Restenosis of the dilated vessel after percutaneous transluminal coronary angioplasty can be detected by non-invasive procedures but their ability to predict later restenosis soon after a successful angioplasty as well as recurrence of angina has not been assessed. A maximal exercise test and myocardial thallium perfusion scintigraphy were, therefore, performed in 91 asymptomatic patients a median of 5 weeks after they had undergone a technically successful angioplasty. Primary success of the procedure was confirmed by the decrease in percentage diameter stenosis from 64(12)% to 30(13)% as measured from the coronary angiograms and in the trans-stenotic pressure gradient (normalised for mean aortic pressure) from 0.61(0.16) to 0.17(0.09). A clinical follow up examination (8.6(4.9) months later) was carried out in all patients and a late coronary angiogram obtained in 77. The thallium perfusion scintigram showing the presence or absence of a reversible defect was highly predictive for restenosis whereas the exercise test was not. The positive predictive value of an abnormal scintigram was 82% compared with 60% for the exercise test (ST segment depression/or angina or both at peak workload). Angina or a new myocardial infarction occurred in 60% of patients with abnormal and in 21% of patients with normal scintigrams.

Comparison of clinical effects of propranolol (Inderal) with once daily slow-release oxprenolol (Slow Trasicor) in angina pectoris.

In a double-blind, crossover, randomized study, the therapeutic effectiveness of a single daily dose of slow-release oxprenolol (160 mg/day) was compared with a conventional dosage schedule of propranolol (40 mg three times daily) in eighteen patients with uncomplicated, stable exercise-induced angina pectoris. Compared to control values both drugs produced equipotent reduction in the frequency and severity of anginal attacks accompanied by a significant increase in exercise tolerance, a significant suppression of exercising heart rate and an appreciable reduction in the electrocardiographic evidence of myocardial ischaemia when tested on a treadmill. The possible advantages offered by a single dose treatment with slow-release oxprenolol are discussed.