Comparative accuracy of clinical tests for diagnosis and prognosis of coronary artery disease

The discriminant accuracy of 14 variables derived from clinical evaluation, cardiac fluoroscopy, exercise electrocardiography, thallium scintigraphy and radionuclide angiography was assessed with respect to the diagnosis of angiographic coronary artery disease (CAD) among 607 patients undergoing coronary angiography, and with respect to the prognosis of subsequent cardiac death or nonfatal infarction among 4,104 patients followed for 1 year after testing. Discriminant accuracy (quantified in terms of the area under a receiver-operating characteristic curve for each variable) ranged from 50 to 73% for diagnosis, and from 54 to 77% for prognosis. Although there was a great deal of variability from test to test, variables representing direct or indirect manifestations of myocardial ischemia tended to correlate better with prognosis. Thus, variables derived from radionuclide angiography and thallium scintigraphy tended to have more prognostic accuracy than diagnostic accuracy, while fluoroscopy tended to have more diagnostic accuracy than prognostic accuracy. The pattern associated with clinical evaluation and exercise electrocardiography was less discernable. Accordingly, the accuracy of noninvasive tests with respect to diagnosis and prognosis of CAD should be separately determined based on individual empiric observation.     

Detection of coronary artery disease in diabetic patients

Summary Coronary artery disease may be difficult to detect in diabetic patients. This study was designed to determine the specificity and sensitivity of three non-invasive tests. Accordingly, the results of 48-h ambulatory electrocardiogram (ECG) monitoring, maximal ECG exercise test, and intravenous dipyridamole myocardial thallium scintigraphy were compared in 59 middle-aged diabetic patients who were consecutively selected for suspected coronary artery disease. All patients also underwent coronary angiography, which was performed regardless of the results of the non-invasive tests. Twenty patients (34%) had significant coronary lesions, i.e. stenosis equal to or greater than 70%, and 16 of these 20 patients (80%) had double or triple vessel disease. Sensitivity and specificity were, respectively, 25% and 88% for ambulatory ECG monitoring, 75% and 77% for the exercise test and 80% and 87% for thallium myocardial scintigraphy. This observation strongly supports the use of non-invasive tests for the detection of coronary artery disease in those diabetic patients at high risk of such disease. As the exercise test is cheaper and more widely available than thallium myocardial scintigraphy it should be used as a first line examination. Dipyridamole myocardial scintigraphy may provide an alternative solution for those patients who cannot perform maximal exercise, or with atypical clinical presentation.Abbreviations ECG Electrocardiogram - CAD coronary artery disease - IDDM insulin-dependent diabetes mellitus - NIDDM non-insulin-dependent diabetes mellitus     

Exercise thallium-201 myocardial scintigraphy in women: Correlation with coronary arteriography

Results of exercise thallium-201 myocardial perfusion images, obtained in 60 women suspected of having coronary artery disease, were correlated with coronary angiographic findings. Thirty-two patients had no significant coronary artery disease; 28 patients had severe coronary artery disease defined as 70 percent or greater diameter narrowing of one vessel (14 patients) or multiple vessels (14 patients). The exercise electrocardiogram was positive in 17 patients (9 with and 8 without coronary artery disease), negative in 16 patients (3 with and 13 without coronary artery disease) and inconclusive in 27 patients (16 with and 11 without coronary artery disease). The exercise thallium-201 scintigram showed exercise-induced defects (reversible ischemia) in 21 patients with coronary artery disease, a fixed defect in 1 patient with single vessel disease and previous transmural infarction, but was normal in the remaining 6 patients, who had single vessel disease. The exercise thallium-201 scintigram in subjects with no coronary artery disease was normal in 28, showed an exercise-induced defect in 1 subject and a fixed defect in the remaining 3 subjects. These fixed defects involved the anterolateral segment in the anterior projection and are thought to be due to attenuation of activity by the overlying breasts. Thus, the sensitivity of the exercise electrocardiogram was 32 percent and the specificity 41 percent. In contrast, the sensitivity of exercise thallium-201 scintigraphy was 75 percent and the specificity 97 percent if only exercise-induced defects were considered abnormal and 79 and 88 percent, respectively, if all fixed defects were considered abnormal.It is concluded that exercise thallium scintigraphy is useful in women suspected of having coronary artery disease. Attenuation of activity by breasts may affect the specificity but not the sensitivity. The exercise electrocardiogram is neither sensitive nor specific in this group.     

Arm exercise-thallium imaging testing for the detection of coronary artery disease

Patients with lower limb impairment are often unable to undergo a standard bicycle or treadmill test for the evaluation of coronary artery disease. To establish an alternative method of testing, 50 subjects (aged 56 +/- 10 years) performed arm ergometry testing in conjunction with myocardial thallium scintigraphy. All underwent coronary angiography; significant coronary artery disease (greater than or equal to 70% stenosis) in at least one vessel was present in 41 (82%) of the 50 patients. Thallium scintigraphy was found to have an 83% sensitivity and 78% specificity for detecting coronary disease, compared with a sensitivity and specificity of 54% (p less than 0.01) and 67% (p = NS), respectively, for exercise electrocardiography. In the subgroup of 23 patients who had no prior myocardial infarction or left bundle branch block and were not taking digitalis, thallium scintigraphy had a sensitivity of 80% versus 50% for exercise electrocardiography. Scintigraphy yielded a sensitivity of 84, 74 and 90% for one, two and three vessel disease, respectively. Noninvasive arm ergometry exercise-thallium imaging testing appears to be reliable and useful and should be considered in the evaluation of coronary artery disease in patients with lower limb impairment.     

Prognostic value of thallium-201 myocardial scintigraphy after atrial transoesophageal pacing in patients with suspected coronary artery disease

Fifty-five patients with suspected coronary artery disease underwentplanar thallium-201 myocardial scintigraphy after atrial transoesophagealpacing. Coronary angiography was carried out in all patients.Eighteen patients had no myocardial infarction, but a greaterthan 50% narrowing of at least one main vessel: initial hypoperfusionwith redistribution at 4 h occurred in 16 patients (sensitivity89%). Twenty-one patients had had a previous myocardial infarction:a reversible thallium defect was observed in 12 patients andan irreversible defect in the nine remaining patients. Sixteenpatients had normal coronary arteries: a reversible thalliumdefect was observed in three patients (specflcity 81%). Aftera mean follow-up of 22±13 months (range 6 to 40), 23cardiac events occurred: cardiac death in one patient, unstableangina in three, and revascularization procedures for recurrentangina despite medical therapy in 19 (coronary artery bypasssurgery in 7 and coronary angioplasty in 12). By univariateanalysis, the predictors of future cardiac events were a historyof previous myocardial infarction (odds ratio 55, P<0.02)multivessel coronary artery disease (odds ratio 9.6, P<0.0002),angina during atrial pacing (odds ratio 5.1, P<0.05), abnormalscintigraphy (odds ratio 17.1, P<0.001) and reversible perfusiondefect after pacing (odds ratio 7.9, P<0.002). By multivariateanalysis, multivessel disease (P<0.004) and reversible perfusiondefect after pacing (P<0.02) were the only independent predictorsof future cardiac events. In conclusion, thallium-201 myocardial scintigraphy after transoesophagealatrial pacing is accurate for the diagnosis and prognosis ofpatients with suspected coronary artery disease, and may beundertaken in patients unable to perform exercise stress testing.     

Diagnostic accuracy of peak exercise echocardiography in coronary artery disease: comparison with thallium-201 myocardial scintigraphy

To evaluate the accuracy of exercise two-dimensional echocardiography for the recognition of coronary artery disease, 53 patients (46 men and 7 women, age range 35 to 69 years) without either previous myocardial infarction or resting wall motion abnormalities, were studied. According to coronary angiography 26 had normal coronary arteries, 14 had one-vessel, seven had two-vessel, and six had three-vessel disease. After withdrawal of any therapy, all patients underwent a single exercise stress test with a stress table during which cine-loop digitized echocardiography was acquired and 74 MBq of thallium-201 (TI-201) were injected. Echocardiographic images were evaluated at rest and at peak exercise. Three-view planar scintigraphic images were collected immediately after exercise and 4 hours later. For the overall recognition of coronary artery disease, exercise electrocardiography had 77.8% sensitivity and 65.4% specificity; myocardial scintigraphy had 100% sensitivity and 92.3% specificity; and exercise echocardiography had 92.6% sensitivity and 96.2% specificity (both NS versus myocardial scintigraphy). Global accuracy was 71.7% for exercise electrocardiography, 94.3% for stress echocardiography, and 96.2% for myocardial scintigraphy. For the classification of the individual involved coronary arteries, the sensitivity of myocardial scintigraphy was 84.8% and that of exercise echocardiography was 63% (p less than 0.01); the related specificities were 98% and 98.2% respectively (NS). It may be concluded that exercise echocardiography is highly accurate for the recognition of coronary artery disease, whereas it appears less sensitive in the identification of the involved vessels, particularly in patients with multivessel disease.     

Segmental analysis of stress thallium201 scintigraphy for the diagnosis and localization of coronary artery disease

Ninety-two patients (15 devoid of coronary artery disease, 24with atherosclerotic coronary lesions but without antecedentmyocardial infarction, 20 with prior anterior myocardial infarction,33 with prior inferior infarction) were submitted to a stresselectrocardiogram and thallium201 scan within the three monthspreceeding or the month following a coronary angiogram. Thisstudy first confirmed that by using a segmental analysis ofthe scans, the localization of the coronary lesion responsiblefor the appearance of zones of hypofixation can be determined.In general, however, defects appear only in the territory ofthe most stenosed vessels. For the detection of coronary diseasein the absence of antecedent myocardial infarction, the exerciseelectrocardiogram showed a sensitivity of 54% and a specificityof 67%. The sensitivity (92%) and specificity (93%) of stressmyocardial scintigraphy were clearly superior. Stress thallium201scintigraphy detected 60% of the patients with anterior infarctionand multiple vessel disease, but suggested the existence ofmultiple lesions in three out of five subjects with isolatedLAD disease. After inferior infarction, multiple vessel diseasewas detected by scintigraphy with a sensitivity of 45% and aspecificity of 82%. If an apical defect in the anterior viewwas considered to be the sign of LAD artery stenosis, the sensitivityof stress myocardial scintigraphy for the detection of multiplevessel disease in the presence of inferior myocardial infarctionreached 86% and the specificity 54%. Stress thallium²⁰¹ myocardialscintigraphy appears more sensitive and specific than exerciseelectrocardiography for the detection of coronary artery diseaseand residual ischaemia after myocardial infarction.     

Diagnosis of chronic coronary failure by clinical aspects, ECG and myocardial scintigraphy after infusion of isoprenaline. Comparison with coronarography

The purpose of this study was to assess the ability of isoproterenol (IPNA) to provoke chest pain, electrocardiographic (ECG) changes and transient defects on thallium 201 myocardial scintigraphy for coronary artery disease (CAD) diagnosis. Thirty patients without prior myocardial infarction who underwent coronary angiography were included. Significant stenosis was found in 15 and absent in the other 15. The most relevant clinical and ECG data were observed in the few minutes that followed IPNA perfusion: 1) angina pectoris occurred in ten patients of whom eight had CAD (sensitivity: 53 p. cent + 13 p. cent; specificity: 87 p. cent + 9 p. cent); 2) ST segment depression was observed in 11 CAD and 3 non-CAD patients (sensitivity: 73 p. cent + 11 p. cent; specificity: 30 p. cent + 10 p. cent); 3) reversible perfusion defects on planar myocardial thallium 201 scintigrams occurred in 16 patients of whom 13 had CAD. Thallium scintigraphy sensitivity was 87 p. cent + 9 p. cent and specificity was 80 p. cent + 10 p. cent. The combined interpretation and stochastic sequential analysis of two or three presumed independent criteria increased significantly the diagnostic value of the test. We conclude that the isoproterenol test is a safe and reliable method to provoke myocardial ischemia with clinical, ECG and myocardial scintigraphic expression. It has an information content nearly identical to exercise stress test for CAD detection. Because it allows a three step sequential probability analysis, the diagnosis is more reliable than with other pharmacological tests which apply only to scintigraphy.     

Serial Exercise Thallium Myocardial Perfusion Scanning and Exercise Electrocardiography in the Diagnosis of Coronary Artery Disease*

Summary: Serial exercise thallium-201 myocardial perfusion scanning (exercise and 4-hour redistribution) was compared to rest and exercise electrocardiography (ECG) for the detection of coronary artery disease in 125 patients with known or suspected coronary artery disease. All patients underwent coronary arteriography and 108 were found to have significant coronary artery lesions. The serial exercise thallium scan was significantly more sensitive than rest and exercise ECG in detecting coronary artery disease (94% v. 83% P <0.01). The sensitivity of a reversible thallium perfusion scan abnormality and a positive exercise ECG for detecting exercise induced myocardial ischaemia in coronary artery disease was similar (69% v. 63%). The exercise thallium scan complemented the exercise EGG, and the sensitivity of the combined test was significantly greater than the exercise ECG alone (84% v. 63% P<0.001). The specificity for coronary artery disease of the exercise ECG was 65% and that of the exercise thallium-201 myocardial perfusion scan was 82% (P = NS). Thallium-201 myocardial perfusion scanning complements the rest and exercise ECG in the non-invasive detection of coronary artery disease.     

Clinical value of immediate thallium-201 reinjection imaging for the detection of ischaemic heart disease

Immediate reinjection of thallium-201 after acquisition of thestress images followed by imaging 60 min later has been proposedas a novel time-saving and patient-convenient approach for theevaluation of myocardial ischaemia and viability. The objectiveof this study was to establish the clinical value of thallium-201stress immediate reinjection imaging in the evaluation of patientswith suspected and known coronary artery disease. Quantitative planar thallium-201 stress immediate reinjectionimaging was performed in 138 patients with undiagnosed chestpain, of whom 114 underwent cardiac catheterization and 24 hada <5% likelihood for coronary artery disease; 56 patientshad previously suffered a myocardial infarction. Sensitivitiesand accuracies were determined for coronary artery disease,reversible myocardial ischaemia, and myocardial viability. Of the 138 patients studied for coronary artery disease, thalliumstress scintigraphy identified 85 of 93 patients with angiographicallyproven coronary artery lesions (overall sensitivity 91%). Thenormalcy rate in the low-likelihood patients was 88% (21 of24 patients) and the overall diagnostic accuracy was 83%. Inthe 56 patients who had suffered a previous myocardial infarction,and in whom the suitability for reversible ischaemia was sought,the overall patient-related sensitivity and accuracy were 93%and 92% respectively. In the 56 patients with a previous myocardialinfarction a total of 168 vessel regions were studied to detectviability. Of the 142 normal or hypokinetic regions, 127 regionswere scintigraphically identified as viable (sensitivity 89%). The thallium stress immediate reinjection imaging protocol isan appropriate clinical approach in patients with undiagnosedchest pain. The combined identification of stress-induced ischaemiaand viability by thallium stress immediate reinjection imagingprovides adequate algorithms allowing optimal management andrisk assessment in the individual cardiac patient.     

Thallium-201 exercise testing in patients 6-8 weeks after myocardial infarction: limited value for the detection of multivessel disease

In a clinical study, the value of exercise electrocardiographyand thallium-201 scintigraphy was determined for the detectionof multivessel disease in 176 patients 6–8 weeks aftera first myocardial infarction. In all patients coronary arteriographywas performed within 3 days after the non-invasive procedure. Of the 176 patients, 77 patients had multivessel disease (prevalence44%). The exercise electrocardiogram was positive in 49 of these77 patients (sensitivity 64%), while the thallium scintigramwas positive in only 24 patients (sensitivity 31%). When theresults of both procedures were added, a moderate sensitivity of 66% and a similar specificity of 62% was found; the positiveand negative predictive values were 57% and 70%, respectively,and were considered too low for the adequate clinical diagnosisof multivessel disease after myocardial infarction. Based on our results, it is concluded that qualitative assessmentof thallium exercise scintigraphy, alone or combined with electrocardiography,should not be used to predict the absence or presence of multivesseldisease in patients after previous myocardial infarction.     

Dipyridamole echocardiography

Intravenous dipyridamole is a potent coronary vasodilator that has been extensively investigated over the past several years in the noninvasive assessment of patients with suspected coronary artery disease when exercise cannot be performed or is suboptimal. As an alternative to exercise studies, dipyridamole has been used in combination with different cardiac imaging techniques such as echocardiography, thallium scintigraphy, and radionuclide ventriculography. Extensive experience has been obtained with dipyridamole thallium-201 imaging for coronary artery disease screening, risk stratification, and prognosis after an acute coronary event. However, experience with the use of dipyridamole in combination with two-dimensional echocardiography has been limited. Dipyridamole increases coronary blood flow in nondiseased coronary vessels relative to coronary vessels with significant luminal narrowings. These provide the basis for detecting regional differences in flow by using different cardiac imaging techniques. Two-dimensional echocardiography would show regional wall-motion abnormalities in response to those regional differences in coronary blood flow. In this article, the most commonly used protocols, safety, and practicability of dipyridamole echocardiography are reviewed. As an alternative to exercise, dipyridamole echocardiography shares all the indications of a standard exercise test. Clinical applications of dipyridamole echocardiography include coronary artery disease screening, suspected coronary artery spasm, postmyocardial infarction risk stratification, evaluation of percutaneous transluminal coronary angioplasty results, and prognosis following an acute coronary event. Compared to conventional (ECG) exercise testing, dipyridamole echocardiography appears to be equally sensitive but more specific. Compared to atrial pacing, dipyridamole provokes ischemia at a lower rate pressure product and results in a greater ST segment depression suggesting that dipyridamole induces more profound myocardial ischemia than atrial pacing. Dipyridamole thallium and exercise thallium have shown to be equally sensitive and specific in the assessment of coronary artery disease. High dose dipyridamole echocardiography appeared to be equally sensitive and more specific. Experimental studies have demonstrated that dobutamine appears to be a more powerful pharmacological agent in inducing wall-motion abnormalities. Dipyridamole echocardiography as compared to stress echocardiography offers the advantage of obtaining better quality postintervention images. With regard to sensitivity and for coronary artery disease diagnosis, both techniques appear to render similar results. Although further studies are needed, the available data indicates that cardiac ultrasound imaging prior to and following the intravenous administration of dipyridamole may be an attractive alternative to thallium perfusion imaging in the clinical setting, particularly when radionuclide capabilities are not present.     

Accuracy of cardiokymography during exercise testing: results of a multicenter study

To determine the diagnostic accuracy of cardiokymography, recorded 2 to 3 minutes after exercise, 617 patients undergoing cardiac catheterization were evaluated from 12 participating centers using a standardized protocol. Adequate cardiokymographic tracings, which were obtained in 82% of patients, were dependent on the skill of the operator and on certain patient characteristics. Of the 327 patients without prior myocardial infarction who had technically adequate cardiokymographic and electrocardiographic tracings, 166 (51%) had coronary disease. Both the sensitivity and specificity of cardiokymography (71 and 88%, respectively) were significantly greater than the values for the exercise electrocardiogram (61 and 76%, respectively, both p less than 0.01). Coronary artery disease and multivessel disease were present in 98 and 68%, respectively, of the 70 patients with concordantly positive cardiokymographic and electrocardiographic results, and in 15 and 5%, respectively, of the 132 patients with concordantly negative test results (p less than 0.001). Cardiokymography was most helpful in those patients in whom the posttest probability of coronary disease was between 21 and 72% after exercise electrocardiography. In these patients a concordantly positive cardiokymographic result increased the probability of coronary disease to between 67 and 100%, whereas a negative response decreased it to between 12 and 15%. In the subgroup of 102 patients undergoing concomitant exercise thallium testing, the sensitivity and specificity for the thallium scintigraphy (81 and 80%, respectively) were similar to the values for cardiokymography (72 and 84%, respectively; differences not significant). Thus, cardiokymography performed during exercise testing improves the diagnostic accuracy of the electrocardiographic response and provides an additional and cost-effective indicator of myocardial ischemia.     

Diagnostic and prognostic value of vasodilator stress echocardiography in asymptomatic Type 2 diabetic patients with positive exercise thallium scintigraphy: a pilot study.

AIM: To assess the diagnostic and prognostic value of vasodilator stress echocardiography in Type 2 diabetic patients with positive exercise perfusion scintigraphy. METHODS: Of an initial cohort of 50 asymptomatic Type 2 diabetic patients undergoing exercise single photon emission computed tomography (SPECT) thallium scintigraphy, 24 had a positive thallium scan, with a reversible perfusion defect. All these 24 underwent high dose (up to 0.84 mg/kg in 10 min) dipyridamole echocardiography and coronary angiography independently of stress echocardiography results. All patients were then followed for 61+/-22 months. RESULTS: Coronary angiography showed normal coronary arteries in 11 patients and significant (> 50% visually assessed diameter reduction in a major vessel) coronary artery disease in 13. Stress echocardiography showed 92% sensitivity and 100% specificity for non-invasive detection of coronary artery disease. During follow-up, five patients experienced cardiac events: heart failure in one, angina with subsequent revascularization in two, and myocardial infarction in two. Event-free survival was 100% in the 12 patients with negative and 58% in the 12 patients with positive stress echocardiography (P = 0.08 by Mantel-Cox test). CONCLUSIONS: In asymptomatic Type 2 diabetic patients with stress-induced perfusion defects, vasodilator stress echocardiography is an excellent diagnostic and prognostic tool proven with long-term follow-up.     

Anterior ST segment depression during the exercise test in patients with previous inferior myocardial infarct. Scintigraphic and coronary arteriographic correlations

Left ventriculography and coronary arteriography were performed in 49 patients: agreement on location of infarcted area was present between ventriculography and ECG in 22 cases and between ventriculography and myocardial scintigraphy in 34 cases (p less than 0.00125). Consequently on the basis of the scintigraphic redistribution image, all our patients were divided in 2 Groups: Group A, with inferior infraction (120 cases), and Group B, with infero-posterior or posterior infarction (68 cases). Exercise test showed anterior ST segment depression in 97 patients (59 from Group A and 38 from Group B). In these cases myocardial scintigraphy showed anterior ischemia in 48 (81%) patients of Group A and only in 17 (45%) of Group B (p less than 0.005). In patients with negative exercise test, myocardial scintigraphy detected anterior ischemia with similar incidence in both groups (about 40%). Out of the 49 patients studied by coronary arteriography, 33 had left anterior descending coronary artery disease: exercise test induced anterior ST depression in 25 of them (sensitivity 77%), while myocardial scintigraphy showed anterior ischemia in 29 (sensitivity 87%). Normal coronary arteries or isolated right or circumflex artery disease were found in 16 patients: 9 of them had anterior ST depression (specificity 56%) and none showed scintigraphic evidence of anterior ischemia (specificity 100%). In conclusion, in patients with previous infarction of inferior and/or posterior wall, ST-segment depression induced by exercise in anterior leads can be a false positive result, without a corresponding anterior myocardial ischemia. This finding is more often observed in patients with infarction of the posterior wall, in whom anterior ST depression on exercise might be due to ischemia or dyssynergy of the infarcted area. Myocardial scintigraphy allows a more precise identification of the scar location, and above all it is provided with good sensitivity and specificity in identifying residual ischemia due to left anterior descending coronary disease.     

Assessment of single vessel coronary artery disease: results of exercise electrocardiography, thallium-201 myocardial perfusion imaging and radionuclide angiography

The sensitivity of the commonly used stress tests for the diagnosis of coronary artery disease was analyzed in 46 patients with significant occlusion (greater than or equal to 70% luminal diameter obstruction) of only one major coronary artery and no prior myocardial infarction. In all patients, thallium-201 perfusion imaging (both planar and seven-pinhole tomographic) and 12 lead electrocardiography were performed during the same graded treadmill exercise test and radionuclide angiography was performed during upright bicycle exercise. Exercise rate-pressure (double) product was 22,307 +/- 6,750 on the treadmill compared with 22,995 +/- 5,622 on the bicycle (p = NS). Exercise electrocardiograms were unequivocally abnormal in 24 patients (52%). Qualitative planar thallium images were abnormal in 42 patients (91%). Quantitative analysis of the tomographic thallium images were abnormal in 41 patients (89%). An exercise ejection fraction of less than 0.56 or a new wall motion abnormality was seen in 30 patients (65%). Results were similar for the right (n = 11) and left anterior descending (n = 28) coronary arteries while all tests but the planar thallium imaging showed a lower sensitivity for isolated circumflex artery disease (n = 7). The specificity of the tests was 72, 83, 89 and 72% for electrocardiography, planar thallium imaging, tomographic thallium imaging and radionuclide angiography, respectively. The results suggest that exercise thallium-201 perfusion imaging is the most sensitive noninvasive stress test for the diagnosis of single vessel coronary artery disease.     

Safety and diagnostic accuracy of adenosine thallium-201 scintigraphy in patients unable to exercise and those with left bundle branch block.

Three hundred forty consecutive patients (mean age 69 +/- 9 years) were evaluated with adenosine tomographic thallium-201 scintigraphy for suspected coronary artery disease. Minor side effects occurred in 91% of patients. Out of 28 patients (8%) with potentially serious side effects, 28 had significant atrioventricular (AV) block (second-degree, 24 patients; third-degree, four patients; syncope occurred in two patients). Acute bronchospasm and severe refractory angina pectoris occurred in one patient each. All side effects were transient and without sequelae. One hundred twenty-one patients underwent coronary angiography within 9 days of adenosine thallium imaging. The predictive accuracies of adenosine thallium imaging for identifying and localizing ischemia to a specific coronary distribution were: left anterior descending = 88%, left circumflex = 84%, right coronary = 88%. The predictive accuracy of adenosine thallium imaging in patients with left bundle branch block was 91%, and was higher than the 71% predictive accuracy noted in 39 patients who underwent exercise thallium testing (p = 0.04). It is concluded that adenosine thallium-201 myocardial scintigraphy was (1) highly accurate for the detection and localization of significant coronary artery disease; (2) it was more accurate at detecting ischemia in patients with left bundle branch block than exercise thallium testing, and (3) subjective side effects were common and were of no diagnostic importance; transient AV block occurred occasionally.     

Prognostic value of exercise thallium scintigraphy in patients with good exercise tolerance and a normal or abnormal exercise electrocardiogram and suspected or confirmed coronary artery disease.

Exercise thallium scintigraphy is widely used to assess prognosis in patients with suspected or proven coronary artery disease. The incremental prognostic value of this technique in patients who have good exercise tolerance has not been well studied. Two hundred ninety-nine patients with known or suspected coronary artery disease without prior myocardial infarction or revascularization procedure referred for exercise myocardial perfusion imaging and able to exercise to greater than or equal to stage III of the Bruce protocol were included. After a mean follow-up of 50 +/- 10 months, there were 15 cardiac events (5%). The incidence of cardiac events was 10 versus 3% (p less than 0.001) in patients with an abnormal versus normal thallium-201 scan, and 9 versus 3% (p = 0.03) for an abnormal versus normal exercise electrocardiogram. When the 185 patients with a normal exercise electrocardiogram were examined, the incidence of cardiac events was 3% (5 of 150) in patients with a normal scan versus 0% (0 of 35) in patients with an abnormal scan. In the 114 patients with an abnormal exercise electrocardiogram, an abnormal thallium-201 scan was predictive of cardiac events (18% [8 of 44] versus 3% [2 of 70]; p = 0.006). Stepwise logistic regression analysis selected an abnormal thallium-201 scan and abnormal exercise electrocardiogram, low peak exercise heart rate, and male gender as independent variables associated with a significant increased risk of cardiac events. Thus, in patients with known or suspected coronary artery disease and good exercise tolerance, the addition of thallium-201 imaging in patients with an abnormal exercise electrocardiogram provides useful prognostic information.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of antianginal medications on the prognostic value of exercise thallium scintigraphy

Whether administration of antianginal medications at the time of exercise thallium scintigraphy reduces the prognostic value of this test was retrospectively examined using two year follow-up of 201 patients. Sensitivity, specificity, positive and negative predictive values and accuracy of five test outcomes for prediction of coronary events (unstable angina, myocardial infarction, cardiac death) were compared between groups of patients either taking or not taking antianginal medications. Specificity and negative predictive value of exercise and redistribution thallium scores for prediction of coronary events were greater in patients not taking antianginal medication (P less than 0.05). It was concluded that normal exercise thallium scintigraphy affords greater assurance against future coronary events in patients tested while not taking antianginal medications.     

Prognosis and thallium-201 scintigraphy in patients admitted with chest pain without confirmed acute myocardial infarction.

Exercise and rest thallium scintigraphy and exercise electrocardiography were performed after discharge in 158 patients aged less than 76 years admitted with chest pain in whom a suspected diagnosis of acute myocardial infarction had not been confirmed. During a follow up of 12-24 months (median 14 months) there were 10 cardiac events--that is, non-fatal acute myocardial infarction or cardiac deaths. Transient thallium defects and abnormal ST response (that is ST segment deviation or uninterpretable ST segment) during exercise were correlated significantly with an unfavourable prognosis. One hundred and four patients with neither of these characteristics were at lower risk of a cardiac event than the 19 patients with both of these characteristics. The percentages of patients in these two groups without a cardiac event after one year were 98.1 and 78.8 respectively. Thallium scintigraphy, alone or in combination with exercise electrocardiography, can be used to identify groups at high and low risk of future cardiac events, in patients with chest pain in whom acute myocardial infarction is suspected but not found.