A computer-derived treadmill exercise score that quantifies the electrocardiographic response to exercise has been reported to have a high sensitivity (87 per cent) and specificity (92 per cent) in patients with a high prevalence of coronary artery disease. To test its accuracy in young, asymptomatic men with a low prevalence of coronary artery disease, we evaluated the responses of 377 military officers (mean age, 36.6 years) by two independent methods. According to standard electrocardiographic criteria, 45 of the subjects (12 per cent) had positive tests, whereas the treadmill exercise score indicated that only 3 (less than 1 per cent) had positive tests. Since two of these three had left ventricular hypertrophy and met only the criteria for the latter without associated coronary artery disease, the treadmill exercise score predicted that only 1 of 377 subjects would have clinically important coronary artery disease. Coronary arteriography, performed in 10 persons with the most positive scores on standard treadmill tests and the highest scores for risk factors, showed that nine subjects did not have coronary artery disease and that one had single-vessel disease (the same subject who the treadmill score predicted would have mild disease). The treadmill exercise score appears to improve the diagnostic specificity of exercise electrocardiography and may be more useful than values on standard stress tests in screening asymptomatic populations for coronary artery disease.
A 54-year-old man with end-stage renal disease presented with chest pain. Five months before presentation the patient had a right-foot cellulitis that was treated with amoxicillin clavulanate. Two weeks later, the patient suffered an inferior wall ST-elevation myocardial infarction that required immediate percutaneous coronary intervention with paclitaxel-eluting stents (Taxus, Boston Scientific, Natick, Mass) in the proximal and mid-right coronary artery (RCA). Over the next 4 months, the patient had recurrent fevers and grew Staphylococcus aureus on repeat blood cultures. The source of infection was attributed to recurrent infected dialysis catheters. The patient had 3 catheter replacements and was treated with intravenous vancomycin and oral rifampin. On examination, the patient had a continuous murmur along the right sternal border and an elevated troponin I level of 2.45 ng/mL (normal range: 0.00 to 0.09 ng/mL).Coronary angiography revealed an occluded proximal RCA stent (asterisks in Figure 1, and Movie I, online-only Data Supplement), a large pseudoaneurysm off the stent (arrowhead in Figure 1), and a fistula into the right atrium (RA) (arrow in Figure 1). A 64-slice multidetector computed tomographic angiogram (GE Healthcare, Chalfont St. Giles, United Kingdom) confirmed both the pseudoaneurysm (arrowhead in Figures 2 and 3) and fistula into the RA (arrow in Figures 2 and 3). Transesophageal echocardiogram (Siemens, Malvern, Pa) identified serpiginous echodensities (arrowhead in Figure 4A, and Movie II, online-only Data Supplement) along the RA wall consistent with vegetation and a fistula inflow from the RCA (arrow in Figure 4B, and Movie III, online-only Data Supplement).The patient underwent a resection of the RCA stents and pseudoaneurysm, evacuation of the RA vegetation, and coronary bypass to the distal RCA with a saphenous vein graft. Microscopic specimen from the RA revealed tissue necrosis with a predominance of neutrophils consistent with an abscess ( Figure 5). The patient received intravenous nafcillin and oral rifampin for an additional 6 weeks after surgery. The patient is doing well 6 months after the operation.To date, there have been only 4 other reported cases of drug-eluting coronary stent infections. [1][2][3][4] In all cases S. aureus bacteremia was responsible for causing mycotic stent complications. Although mycotic aneurysms, pseudoaneurysms, and abscesses have been previously reported in both bare-metal and drug-eluting stent infections, this is the first reported case of an infected coronary stent that developed an intracardiac fistula. The mechanism of drug-eluting stent infection is not well understood. Potential causes for drugeluting stent infections include impairment of local immunosuppression and endothelialization caused by the paclitaxel or sirolimus released from the stent and/or bacteremia at the time of catheterization. [1][2][3][4] In fact, Ramsdale et al reported that up to 17.7% of patients who underwent complex percutaneous coronary interventions had detectable b...
This study was undertaken to develop a quantitative scintigraphic measurement of ischemia. We recorded 201TI scintigrams by the seven-pinhole tomographic technique immediately after exercise and 3 hr later in 15 normal subjects with a low likelihood of coronary disease and in 55 catheterized patients with chest pain. Circumferential profiles of the initial and 3 hr tracer distribution and of the 3 hr clearance rate were generated for each of three left ventricular sections. A circumferential profile of the 3 hr clearance rate (initial counts minus 3 hr counts divided by initial counts, expressed as percent) was also generated for each of these sections. A scintigraphic ischemic score (SIS) was then derived by summing for the three sections the area (in arbitrary units) between the exercise and 3 hr profiles and the area by which the clearance profile fell below the lower limits of normal for clearance derived from the normal subj'ects. This summed area was then normalized for the level of stress by dividing by the product of the exercise duration (in minutes) and the fraction of agepredicted maximum heart rate achieved. This SIS was above the 95% confidence limits derived from the normal subjects in 44 of 46 (96%) patients with the significant coronary disease and in only one of nine with less than a 50% obstruction. The SIS was 52 + 58, 233 + 220, 427 325, and 826 551 U (mean SD) for patients without coronary disease and for those with one-, two-, and' three-vessel disease, respectively. The intergroup differences were statistically significant, but there was considerable overlap among individual patients. More importantly, the SIS correlated significantly with a coronary arteriography score designed to reflect the potential for ischemia based on the coronary anatomy (r = .78, p < .001) and with an index of ischemia generated from the exercise electrocardiogram (r = .72, p < .001). These findings suggest that a continuous and quantitative scintigraphic index of myocardial ischemia can be derived from analysis of the postexercise distribution and clearance of 201T1. Such an index should be valuable in determining prognosis and choosing therapy for patients with coronary artery disease and in assessing their response to therapeutic interventions. Circulation 68, No. 4, 747-755, 1983. THALLIUM-201 (207T1) scintigraphy is widely used to detect coronary disease, usually'in conjunction with exercise testing. In addition, many groups have evaluated its ability to localize obstructed vessels and to estimate the extent of anatomic involvement.24 Unfortunately, the scintigraphic results with these latter applications have often been disappointing, at least in part because of the relative nature of the conventional interpretation criteria, which occasionally make it dif-
Although considered a relatively benign congenital coronary anomaly, myocardial bridges have been associated with myocardial ischemia, infarctions, and sudden cardiac death. The aim of this study was to identify characteristics of myocardial bridges on computed tomographic angiography (CTA) associated with abnormal defects on myocardial perfusion imaging (MPI). A retrospective study was performed to identify patients who had myocardial bridges detected by 64-slice multidetector cardiac CTA and prior stress single photon emission computed tomography (SPECT) MPI. Using axial, oblique, and curved multi-planar reformatted images, myocardial bridge characteristics, including length and maximum depth of the tunneled segments, were compared in patients with and without corresponding coronary perfusion defects on SPECT MPI. From a total of 272 patients who had both SPECT MPI and cardiac CTA performed, 23 patients (8%, males= 9, mean age= 57 years) were identified with myocardial bridges. The left anterior descending artery was the predominant affected coronary artery (20/23, 87%). Eight patients (35%) with myocardial bridges had corresponding perfusion defects on SPECT MPI. Increased depth of the tunneled segment was significantly associated with abnormal SPECT MPI compared to normal SPECT MPI (4.1 ± 2.0mm vs. 1.9 ± 0.9mm, respectively, p< 0.002). The length of the tunneled segment did not differ in patients with or without abnormal SPECT MPI (27.8 ± 15.6mm vs. 20.9 ± 12.6mm, respectively, p=0.26). This is the first study to correlate SPECT MPI and 64-slice multidetector cardiac CTA in the evaluation of myocardial bridges. Increased maximum depth of the tunneled segment on cardiac CTA is significantly associated with myocardial perfusion defects.
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