Prognostic implications of rest and exercise radionuclide ventriculography in patients with suspected or proven coronary heart disease

Rest and exercise radionuclide ventriculography were assessed for their value in predicting major cardiac events in patients with chest pain. Of 219 patients who were followed for up to 51 months, 42 had major cardiac events: 12 patients (5.5%) died, 5 (2.2%) sustained nonfatal myocardial infarction, and 25 (11.4%) had coronary arterial bypass grafting. Univariate and multivariate survival analysis revealed that exercise left ventricular ejection fraction was the best predictor for total major events and the resting ejection fraction to be the best predictor for death or nonfatal myocardial infarction. These two variables were strong predictors in the entire group of patients and in subgroups: patients with or without Q-wave infarction, patients with high probability of coronary artery disease and those with abnormal resting left ventricular function. Thus, radionuclide angiography provides important prognostic data that permits the physician to categorize patients with chest pain syndromes with respect to subsequent cardiac events. If validated, this model or a modification of it could identify patients at high risk of subsequent major cardiac events who are candidates for intensive follow up and therapy or further invasive evaluation, as well as patients at low risk of subsequent major cardiac events for whom standard follow up would be appropriate.     

Dipyridamole radionuclide ventriculography in patients with coronary artery disease: comparison with ergometer exercise

Intravenous administration of dipyridamole during radionuclide ventriculography (RNV) was performed in 26 consecutive patients with symptomatic coronary artery disease. The authors compared the results of dipyridamole-RNV with those of ergometer exercise-RNV in detecting myocardial ischemia. During exercise, ST depression, regional wall motion (RWM) abnormalities, and decreased left ventricular ejection fraction (LVEF) were observed in 21 (81%), 23 (88%), and 20 (77%) patients, respectively. However, after intravenous dipyridamole, ST depression, RWM abnormalities, and decreased LVEF were observed in 14 (54%), 15 (58%), and 2 (8%) patients, respectively. Although LVEF usually decreases during myocardial ischemia, LVEF did not decrease (57 +/- 11% to 58 +/- 10%), even in patients with ST depression, after intravenous dipyridamole. Maintained left ventricular ejection fraction is considered to be a hemodynamic effect of the potent arterial vasodilatation induced by dipyridamole. These results from dipyridamole-RNV in myocardial ischemia seem to conflict with the results from dipyridamole-thallium studies carried out to determine the capacity to detect coronary artery disease. Unknown mechanisms of dipyridamole other than the coronary steal phenomenon may be operative in the genesis of myocardial ischemia.     

Applications of exercise radionuclide ventriculography in the clinical management of patients with coronary artery disease

Exercise radionuclide ventriculography is commonly used in patients with coronary artery disease, for both diagnostic purposes and patient management decisions. Both applications are reviewed in this article. There has been much debate as to the diagnostic efficacy of this test. Four factors influence this determination: (1) patient referral biases, (2) the optimal criteria for test interpretation, (3) the technique for performing radionuclide ventriculography, and (4) technical factors. The role of each factor is discussed. After consideration of these factors, it is concluded that the diagnostic efficacy of exercise radionuclide ventriculography is high. This test is used as a criterion for many patient management decisions, such as the need for coronary artery bypass surgery or coronary angioplasty. This test is well suited for such purposes because of its ability to quantitate the magnitude of ischemia. In addition to left ventricular ejection fraction, the importance of the following five wall motion variables are reviewed relative to the information they provide regarding ischemic magnitude: (1) extent, (2) magnitude, (3) time to onset and (4) duration of exercise-induced wall motion abnormalities, and (5) the paradoxical reversal of rest abnormalities following exercise. It is shown how consideration of all potential variables enhances the clinical utility of this test.     

The differing prognostic utility of exercise radionuclide ventriculography in coronary artery disease patients with and without prior myocardial infarction

Previous studies have documented the prognostic utility of left ventricular ejection fraction response to exercise primarily in populations without prior myocardial infarction. We undertook a study to assess the prognostic utility of exercise left ventricular ejection fraction and segmental wall motion response during exercise radionuclide ventriculography in coronary artery disease patients with and without prior myocardial infarction. Methods. We examined the comparative prognostic utility of left ventricular ejection fraction and segmental wall motion response during upright bicycle exercise radionuclide ventriculography in 419 coronary artery disease patients with (n=217) and without (n=202) prior myocardial infarction using univariate and multivariate hierarchical regression analyses. Results. During an average followup period of 61 months, 96 patients (23%) suffered cardiac events, including 55/217 (25%) of the patients with prior myocardial infarction and 41/200 (21%) of the patients without prior myocardial infarction (p=ns). Both cumulative Kaplan-Meier survival analyses and stepwise hierarchical Cox survival analyses demonstrated that peak left ventricular ejection fraction <55% was a significant predictor of cardiac events in patients without prior myocardial infarction (p=0.04), whereas an exercise wall motion worsening score 2 was a significant predictor in patients with a prior myocardial infarction (p=0.0001). Conclusions. The prognostic utility of exercise radionuclide ventriculography variables differ according to the presence or absence of prior myocardial infarction. Global function, assessed by peak left ventricular ejection fraction, adds the greatest prognostic information in patients without prior myocardial infarction, whereas regional function, assessed by exercise wall motion worsening, is the best predictor among patients with prior myocardial infarction.     

Right ventricular systolic and diastolic function at rest in patients with coronary artery disease. Assessment with equilibrium radionuclide ventriculography

Right ventricular systolic and diastolic function was studied in patients with ischemic heart disease using equilibrium radionuclide ventriculography. In patients with inferior myocardial infarction and proximal right coronary lesions, the right ventricular ejection fraction (0.43 +/- 0.06, n = 10, mean +/- SD) and peak filling rate (1.7 +/- 0.4 EDV/sec) were lower than normals (0.57 +/- 0.07 and 2.7 +/- 0.4 EDV/sec, n = 10, p less than 0.001, respectively). In these patients, the right ventricular time to peak filling rate was longer than in normals (225 +/- 36 msec vs 136 +/- 45 msec, p less than 0.001), while the left ventricular ejection fraction remained normal. In patients with inferior myocardial infarction and distal right coronary lesions, the right ventricular ejection fraction, peak filling rate and time to peak filling rate were not different from those in normals. Even in patients with proximal right coronary lesions, the right ventricular ejection fraction was normal unless they had an inferior myocardial infarction. A decreased left ventricular ejection fraction and abnormal motion of the ventricular septum did not affect the right ventricular ejection fraction. The present results suggest that patients with an inferior myocardial infarction and proximal right coronary lesion often develop right ventricular systolic and diastolic dysfunction.     

Exercise radionuclide ventriculography in evaluation of coronary artery disease

The ability of radionuclide variables obtained at rest and at peak exercise to discriminate the number of stenosed (greater than or equal to 70% luminal diameter narrowing) major coronary arteries was evaluated in 296 patients undergoing supine exercise radionuclide ventriculography. Stepwise linear discriminant analysis of the data from the first 200 patients identified a significant (p less than 0.001) discriminatory combination. Application of this function to the remaining 96 patients provided correct classification of arteriographically determined zero, one, two, and three stenosed arteries in 59%, 18%, 14%, and 60% of cases, respectively. The discriminant function classified minimal stenoses (zero or one artery) and multivessel stenoses (two or three arteries) correctly by arteriography in two thirds of cases in each group. Arteriographic presence of three stenoses was unlikely in those classified as having no stenosis, and absence of stenosis was rare in those classified as having three stenoses. Exercise radionuclide ventriculography is most helpful in identifying minimal and multivessel coronary disease rather than number of stenosed major coronary arteries.     

Equilibrium radionuclide right ventriculography at rest and during exercise in patients with pulmonary hypertension

Using the method of equilibrium radionuclide ventriculography (RNV), the right ventricular ejection fraction (RVEF) at rest and at a standard workload of 250 kpm per min was determined in 25 control subjects and in 30 patients with pulmonary hypertension (8 patients with chronic obstructive bronchopulmonary disease, 12 with recurrent pulmonary embolism and 10 with pure mitral stenosis). In the same week as RNV, pulmonary artery pressure was registered in patients with pulmonary hypertension at rest and at standard workload. RVEF was significantly higher (45 +/- 5%) in normal subjects than in patients with pulmonary hypertension (33 +/- 5%) and during exercise increased, whereas in patients with pulmonary hypertension it did not markedly change or decreased. The RVEF correlated at rest (r = -0.6293, p less than 0.001) and during exercise (r = 0.6980, p less than 0.05) with the degree of pulmonary hypertension at rest and during exercise. The results show a good correlation between the RVEF and the degree of pulmonary hypertension in patients with pulmonary hypertension at rest and during exercise.     

Dipyridamole radionuclide ventriculography for localisation of coronary artery disease

Nineteen consecutive patients who had coronary arteriography underwent dipyridamole stress testing with 0.14 mg/kg/min infusion over 4 minutes during computer assisted radionuclide ventriculography. Global ejection fraction, diastolic function and regional ejection fraction were calculated by a semiautomatic method. There were 17 patients with severe left anterior descending disease of which 12 involved the proximal segment of the LAD, 15 patients with left circumflex disease and 13 patients with right coronary artery disease. Abnormalities in resting or stress induced regional ejection fraction was used for localisation of severe coronary artery disease. The overall sensitivity was 75 per cent with a specificity of 75 per cent, a positive predictive value of 90 per cent and a negative predictive value of 45 per cent. For LAD disease the sensitivity was 94 per cent with a 100 per cent specificity while proximal segment of LAD had a sensitivity of 100 per cent and a specificity of 57 per cent. Identification of left circumflex disease had a sensitivity of 47 per cent and a 100 per cent specificity and right coronary artery had a 85 per cent sensitivity and a 50 per cent specificity. Four patients developed ST changes, 6 developed chest discomfort and 1 patient developed giddiness. All 7 were promptly reversed with intravenous aminophylline. Thus dipyridamole radionuclide ventriculography is a highly sensitive and specific method for localisation of CAD.     

The use of coronary artery calcium scanning in detection and risk stratification of coronary artery disease

Coronary artery calcium (CAC) scan can be obtained using chest computed tomography, with no use of contrast agents, and with a relatively low radiation exposure. The mere absence of calcium is associated with a good prognosis in asymptomatic subjects and in patients at low to medium risk of coronary artery disease. CAC can be quantified in different ways, with higher scores being associated with a higher cardiovascular risk. CAC carries both diagnostic and prognostic information over and above that determined by classical risk factors. This paper presents the overview of the current use of CAC scanning, its advantages and limitations, as well as potential future applications.     

Very early risk stratification by electrocardiogram at rest in men with suspected unstable coronary heart disease

Abstract. Objectives. To determine the possibility of very early prognostic stratification based on electrocardiograms (ECGs) at rest and/or cardiac enzyme levels after an episode of suspected unstable coronary heart disease. Design and setting. Men with suspected unstable angina or non-Q-wave myocardial infarction were studied in the coronary care units of eight hospitals. The ECGs at rest and creatinine kinase were followed. Subjects. In total 911 men were followed for 12 months. Of 8136 consecutively admitted, 3365 fulfilled the inclusion criteria. Excluded were 2454 patients, mainly because of a larger myocardial damage, signs of myocardial dysfunction, other serious cardiac or non-cardiac disease or an ECG not possible to interprete regarding ST-T-segment changes in the precordial leads. Main outcome measures. End-points at follow-up were cardiac death, myocardial infarction and severe (class III or IV) angina. Results. Compared to patients with normal a ECG who had an 8% 1-year risk of myocardial infarction or death, the risk with isolated negative T waves was 14% (P < 0.05), ST elevation 16% (P < 0.05), ST depression 18% (P < 0.01) and the combination of ST elevation and ST depression 26% (P < 0.001). The only finding related to future severe angina was ST depression. The risk of cardiac events was comparably elevated in patients with anterior or inferior site of ECG changes. Cardiac enzyme levels had no predictive value regarding future events. Conclusions. Electrocardiograms at rest obtained during the initial days of hospitalization provide very early and valuble prognostic information in men admitted with suspected unstable coronary heart disease.     

Risk stratification and prognosis of patients with known or suspected coronary artery disease by use of supine bicycle exercise stress echocardiography.

BACKGROUND: The aim of this study was to assess the long-term predictive values of supine bicycle exercise stress echocardiography (ESE), and the ESE additional role compared to other traditional clinical and rest echocardiographic variables, in 607 patients with low, intermediate and high pretest risk of cardiac events. METHODS: Clinical status and long-term outcome were assessed for a mean period of 46 months (range 12-60 months). ESE was performed for the diagnosis of suspected coronary artery disease (CAD) in 267 patients (43.9%), and for risk stratification of known CAD in 340 patients (56.1%). At baseline, the mean value of wall motion score index (WMSI) was 1.22 +/- 0.36, and the mean left ventricular ejection fraction was 58.5 +/- 10.9%. RESULTS: ESE was positive for ischemia in 210 patients (34.9%), while ECG was suggestive for ischemia in 157 patients (25.8%). During the test only 97 patients (15.9%) experienced angina. At peak effort, the mean WMSI was 1.38 +/- 0.46. A low workload was achieved by 158 patients (26.1%). During the follow-up period there were 222 events, including 82 hard events (36.9%), 48 deaths (21.6%) and 34 acute non-fatal myocardial infarction (15.3%). At stepwise multivariate model, cigarette smoking (p < 0.01), peak WMSI (p < 0.001), ESE positive for ischemia (p < 0.001) and low workload (p < 0.01) were the only independent predictors of cardiac death, while positive ESE, peak WMSI, angina during the test and hypercholesterolemia were the only independent determinants of hard cardiac events. The cumulative 5-year mean survival rate according to ESE response was 95.9% in patients with negative ESE, and 83.7% in patients with positive ESE (log rank 13.6; p < 0.00001). CONCLUSIONS: ESE yields prognostic information in known or suspected CAD, especially in patients with intermediate pretest risk level. The combined evaluation of clinical variables and other ESE variables, such as peak WMSI and exercise capacity, may further select patients at greatest risk of cardiac death in the overall population.     

Reversal of rest asynergy during exercise in patients with coronary artery disease

The diagnosis of ischemic heart disease by radionuclide ventriculography (RNV) is performed on the basis of an abnormal response of the left ventricular ejection fraction and the occurrence, or aggravation, of regional wall motion abnormality during exercise. However, the abnormal wall motion observed by RNV at rest is improved in some patients with coronary artery disease during exercise. We examined the clinical features of such patients who showed a paradoxical response of regional wall motion. The left ventricle was divided into 4 segments: anteroseptal, apical, inferior and posterolateral. The degree of wall motion of each segment was classified into 5 grades and scored according to a 5 point system: 4 = normokinesis, 3 = hypokinesis, 2 = severe hypokinesis, 1 = akinesis and 0 = dyskinesis. The wall motion score (WMS) was calculated as the sum of each segment score. If the WMS increased by 2 points or more during exercise, the case was defined as having shown significant improvement of wall motion. Improvement in WMS was found in 26 (12%) of 209 serial patients who underwent exercise RNV, exercise thallium myocardial scintigraphy and coronary angiography. Clinically, half of these patients had a variant form of angina pectoris. With respect to coronary lesions in the segments with reversible asynergy, 12 patients had 0 vessel disease, 8 had lesions with stenosis of less than 75% and 3 showed an adequate collateral circulation. Redistribution found on the exercise thallium myocardial scintigram at the same sites of improved wall motion was identified in only 1 patient. An analysis of patients with paradoxical improvement of wall motion during exercise suggests the involvement of coronary spasm, an improvement of coronary flow reserve, such as could be produced by regression or recanalization of the main lesions, or establishment of significant collateral circulation.     

Normal left ventricular emptying in coronary artery disease at rest: analysis by radiographic and equilibrium radionuclide ventriculography

The volume ejected early in systole has been proposed as an indicator of abnormal left ventricular function that is present at rest in patients with coronary artery disease with a normal ejection fraction and normal wall motion. The volume ejected in systole was examined by calculating the percent change in ventricular volume using both computer-assisted analysis of biplane radiographic ventriculograms at 60 frames/s and equilibrium gated radionuclide ventriculograms. Ventricular emptying was examined with radiographic ventriculography in 33 normal patients and 23 patients with coronary artery disease and normal ejection fraction. Eight normal subjects and six patients with coronary artery disease had both radiographic ventriculography and equilibrium gated radionuclide ventriculography. In all patients, there was excellent correlation between the radiographic and radionuclide ventricular emptying curves (r = 0.971). There were no difference in the ventricular emptying curves of normal subjects and patients with coronary artery disease whether volumes were measured by radiographic or equilibrium gated radionuclide ventriculography. It is concluded that the resting ventricular emptying curves are identical in normal subjects and patients with coronary artery disease who have a normal ejection fraction and normal wall motion.     

Comparison of exercise stress testing with dobutamine stress echocardiography and radionuclide ventriculography for diagnosis of coronary artery disease

Dobutamine stress echocardiography, Tc-99m radionuclide ventriculography (RNVG), and exercise stress testing were performed prospectively in 63 patients with suspected coronary artery disease to compare the values of exercise testing, dobutamine stress echocardiography and RNVG in the non-invasive diagnosis of coronary artery disease. The sensitivities of dobutamine stress echocardiography and RNVG were found to be higher than that of exercise testing (93-62%, p < 0.001; 83-62%, p < 0.05). The sensitivities of dobutamine stress echocardiography and RNVG were similar (p > 0.05). There were no differences between the sensitivities of the three techniques in multiple vessel disease (p > 0.05). The specificities of dobutamine stress echocardiography and RNVG were higher than that of exercise testing (for both of the tests 86-62%, p < 0.05). The diagnostic accuracy of dobutamine stress echocardiography and RNVG were similar (p > 0.05). The results of dobutamine stress echocardiography RNVG were concordant with each other in 46 patients (76%, kappa = 65%) in sectional analysis. Dobutamine stress echocardiography and RNVG tests were comparable with each other in 85% of the 189 segments (kappa = 64%). The expected 5% decrease at peak doses of dobutamine was not detected in stress echocardiography in 25 patients and in RNVG in 26 of the patients. Dobutamine stress echocardiography and RNVG are superior to exercise testing in the diagnosis of single vessel disease and there is no significant difference between the two techniques. When the ejection fraction is considered in dobutamine stress echocardiography and RNVG, it does not make an additional contribution to the diagnosis of coronary artery disease.     

Use of exercise thallium-201 imaging for risk stratification of elderly patients with coronary artery disease

Although coronary artery disease (CAD) may be asymptomatic, it is the most common cause of death in elderly patients in the U.S. This study examined the prognosis of 449 patients with a mean age of 65 years using exercise thallium-201 imaging. At a follow-up of 25 months, 45 patients underwent coronary artery revascularization, 8 died of cardiac causes and 10 had nonfatal acute myocardial infarctions (AMIs). Thus the total of patients with "hard" events was 18. The events included 12 of 276 patients with atypical or non-anginal symptoms versus 6 of 128 with typical angina (p = not significant); 7 of 51 patients (14%) with Q-wave AMI versus 11 of 353 (3%) without Q-wave AMI (p less than 0.001); 1 of 183 patients (1%) with normal versus 17 of 221 (8%) with abnormal exercise thallium-201 images (p less than 0.002); 10 of 76 patients (13%) with multi vessel thallium-201 abnormality vs 8 of 328 (2%) with no or 1-vessel thallium-201 abnormality (p less than 0.001) and 10 of 96 patients (10%) with greater than or equal to 3 abnormal segments by thallium-201 imaging (total segments = 9) versus 8 of 308 patients with no or less than 3 abnormal segments (p less than 0.001). The number of segments with thallium-201 defects was 1 +/- 2 patients without and 3 +/- 2 in patients with hard events (p less than 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)