Discriminant function analysis using thallium-201 scintiscans and exercise stress test variables to predict the presence and extent of coronary artery disease

The ability to predict the presence and extent (number of affected vessels) of coronary artery disease objectively from an exercise treadmill test and thallium-201 myocardial perfusion scintiscans was evaluated using linear discriminant function analysis. Exercise and redistribution scans in the 30 ° left anterior oblique view were characterized by their two dimensional Fourier transforms. The analysis was performed in 141 persons, including 110 patients with coronary artery disease (70 percent or greater stenosis of luminal diameter) and 31 control subjects. There were 43 patients with single vessel and 67 patients with multivessel disease.

Input to the discriminant analysis included age, sex, 18 variables from the exercise treadmill test and 36 Fourier frequency coefficients from each scan (exercise and redistribution). Two analyses were performed. In the first, a discriminant function was constructed to detect the presence of coronary artery disease. Seven input variables were chosen: maximal exercise pressure-rate product, sex, anginal pain, change in S-T segment slope with exercise, two Fourier coefficients from the exercise scan and one Fourier coefficient from the redistribution scan. The function correctly classified 103 of 110 patients with coronary artery disease and 27 of 31 control subjects; the estimated sensitivity of the technique is 94 percent, with 87 percent specificity and an overall accuracy of 92 percent for the detection of coronary artery disease. The discriminant function was significantly more sensitive and accurate than qualitative scan interpretation (p < 0.05).

In the second analysis, two discriminant functions were developed to predict the extent of disease. In addition to the preceding variables, the duration of exercise, change in systolic blood pressure during the last two stages of exercise, and another Fourier coefficient from the exercise scan were chosen. Using two functions, the method detected the presence of coronary artery disease in 104 of 110 patients (95 percent sensitivity) and correctly classified 28 of 31 control subjects (90 percent specificity). Multivessel disease was correctly predicted in 53 of 67 patients (79 percent accuracy); another 11 patients with multivessel disease were predicted to have single vessel disease. Twenty-nine (67 percent) of 43 patients with single vessel disease were correctly classified; of the remaining 14 patients, 12 were predicted to have multivessel disease and 2 were judged to have normal vessels.

The data demonstrate that numerical functions derived from the exercise treadmill test variables and Fourier coefficients of thallium-201 scans can be used to detect the presence of coronary artery disease with 92 percent accuracy. The predictive accuracy for the number of diseased vessels was 78 percent (110 of 141 patients classified correctly).     

The cardiokymography exercise test compared to the thallium-201 perfusion exercise test in the diagnosis of coronary artery disease

To determine the usefulness of exercise cardiokymography (CKG) compared to thallium-201 perfusion scanning in the diagnosis of coronary artery disease (CAD), 179 patients with a mean age of 54 +/- 10 years (73% men) were studied. Previously documented CAD was present in 73 patients (41%); 13 (7%) were asymptomatic and 93 (53%) had chest pain syndrome. Exercise stress testing, CKG, and thallium-201 perfusion scanning were independently correlated with coronary angiographic data. Treadmill exercise stress test alone without CKG had a sensitivity of 68% and specificity of 62%. CKG showed a sensitivity of 76% and a specificity of 90%, and easily interpreted cardiokymograms were obtained in 78% of patients studied. Thallium-201 scans had a sensitivity of 79% and a specificity of 88%. However, when the CKG and treadmill exercise test results were concordant (both positive or both negative), the CKG exercise test had a sensitivity of 87% and specificity of 100%. Thus, when the CKG and exercise test results are concordant, the sensitivity and specificity are equal to or better than thallium-201 perfusion scanning for the prediction of CAD. Since CKG is an inexpensive and noninvasive test, its adjunctive use with routine exercise stress testing may be of great value.     

A simplified approach for evaluating multiple test outcomes and multiple disease states in relation to the exercise thallium-201 stress test in suspected coronary artery disease

This study describes a simplified approach for the interpretation of electrocardiographic and thallium-201 imaging data derived from the same patient during exercise. The 383 patients in this study had also undergone selective coronary arteriography within 3 months of the exercise test. This matrix approach allows for multiple test outcomes (both tests positive, both negative, 1 test positive and 1 negative) and multiple disease states (no coronary artery disease vs 1-vessel vs multivessel coronary artery disease). Because this approach analyzes the results of 2 test outcomes simultaneously rather than serially, it also negates the lack of test independence, if such an effect is present. It is also demonstrated that ST-segment depression on the electrocardiogram and defects on initial thallium-201 images provide conditionally independent information regarding the presence of coronary artery disease in patients without prior myocardial infarction. In contrast, ST-segment depression on the electrocardiogram and redistribution on the delayed thallium-201 images may not provide totally independent information regarding the presence of exercise-induced ischemia in patients with or without myocardial infarction.     

Effect of the degree of effort on the sensitivity of the exercise thallium-201 stress test in symptomatic coronary artery disease

The sensitivity of ST-segment depression on the electrocardiogram during exercise is influenced by the level of effort. Whether such is the case with thallium-201 imaging (initial defect or redistribution) has not been established. Accordingly, the prevalence of these parameters was evaluated in 288 patients (age 59 +/- 10 years, 88% men) with coronary artery disease who underwent both exercise thallium-201 imaging and coronary angiography within 3 months of each other: 159 had a prior myocardial infarction, 72 had 1-vessel, and 216 had multivessel disease. The degree of effort was evaluated by 3 criteria: (1) percentage of maximal predicted heart rate (less than or equal to 65, greater than 65 to 85, greater than 85%); (2) workload during exercise (less than or equal to 4, greater than 4 to 8, greater than 8 METs); and (3) duration of exercise (less than or equal to 3, greater than 3 to 6, greater than 6 minutes). The prevalence of defects on initial images was higher than both redistribution on delayed images and ST-segment depression on the electrocardiogram (p less than 0.01). The overall prevalence of initial defects remained the same for all levels of effort and was not influenced by the presence or absence of a prior infarction. However, it decreased in patients with 1-vessel disease who exercised to higher workloads. The prevalence of redistribution on delayed thallium-201 images was higher than that of ST-segment depression on the electrocardiogram (p less than 0.01), except at higher levels of effort where they were similar.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hemodynamic and metabolic correlates of dipyridamole-induced myocardial thallium-201 perfusion abnormalities in multivessel coronary artery disease

The mechanisms responsible for the development of reversible thallium-201 (Tl-201) defects with dipyridamole stress in patients with coronary artery disease (CAD) is not well understood. Previous experimental animal studies have demonstrated coronary steal characterized by an absolute decrease in subendocardial flow distal to a stenosis in response to dipyridamole infusion. Accordingly, the purpose of this study was to determine if reversible Tl-201 defects in response to dipyridamole infusion are reflective of myocardial ischemia or secondary to regional differences in flow reserve. Dipyridamole (0.56 mg/kg) Tl-201 imaging was performed in 23 patients in whom serial electrocardiographic, hemodynamic, aortic and coronary sinus lactate, and coronary sinus adenosine measurements were obtained. All patients with CAD had Tl-201 redistribution (3.8 ± 2.0 defects/patient), and all patients without CAD had normal scans. Mean aortic pressure was similar in both groups and did not change in response to dipyridamole (non-CAD 103 ± 11 vs CAD 99 ± 15 mm Hg, P = NS). Pulmonary capillary wedge pressure was similar at baseline (non-CAD 11 ± 4 vs CAD 13 ± 5 mm Hg, P = NS) and did not change in response to the drug (non-CAD 14 ± 3 vs CAD 15 ± 7 mm Hg, P = NS). Lactate extraction fraction was similar at baseline (non-CAD 0.22 ± 0.09 vs CAD 0.17 ± 0.14, P = NS) and decreased similarly in both groups (non-CAD 0.08 ± 0.06 vs CAD 0.05 ± 0.12, P = NS). Coronary sinus adenosine concentration was significantly higher at baseline in patients with CAD (non-CAD 16 ± 4 vs CAD 35 ± 13 ng/ml, P = 0.034), presumably to maintain resting coronary blood flow, and increased significantly with a comparable percent increase in both groups after dipyridamole (non-CAD 35 ± 10 vs CAD 69 ± 35 ng/ml, P = 0.0001). In this group of patients with multivessel CAD, dipyridamole-induced Tl-201 perfusion abnormalities were not associated with significant myocardial ischemia by hemodynamic and metabolic criteria and appeared to be more indicative of abnormal flow reserve.     

Bayesian analysis using fourier transforms of thallium-201 scintiscans to predict the presence of coronary artery disease

Bayes' theorem of conditional probability was applied to the diagnosis of coronary artery disease (CAD) using thallium-201 scintigraphy as the testing procedure. Thallium-201 scintiscans were evaluated with a discriminant function previously developed using the amplitude coefficients of the Fourier transforms of the scams. The technique was applied prospectively to a population of 100 patients undergoing diagnostic coronary arteriography and thallium-201 scintigraphy, including 83 patients with CAD (70% or greater stenosis of luminal diameter) and 17 control subjects. A pretest probability of CAD was determined for each patient from the patient's age, sex and anginal symptoms. The pretest probability was combined with the patient's discriminant score to determine a posttest probability for CAD. For patients with CAD, the mean posttest probability was 0.85. Moreover, 57 of 83 patients (69%) had posttest probabilities exceeding 90%, including 40 patients (48%) with posttest probabilities exceeding 99%. For control subjects, the mean posttest probability was 0.19, with 11 of 17 (65%) having a posttest probability of less than 10%. Overall, 68 subjects had a posttest probability either less than 10% or more than 90% of which 63 were correctly classified (93%). Using a 50% posttest probability as a cutoff for classification, the technique has an 89% sensitivity, an 82% specificity and an overall accuracy of 88%. Therefore, this method objectively distinguishes patients with CAD from control subjects and provides a measure of the certainty of diagnosis. In addition, the discriminant function avoids the problem of inter- and ihtraobserver variability in visually interpreting thallium-201 scans.     

Prediction of multivessel coronary artery disease and prognosis early after acute myocardial infarction by exercise electrocardiography and thallium-201 myocardial perfusion scanning

Exercise electrocardiography and thallium scanning were performed a mean of 24 days after uncomplicated acute myocardial infarction in 103 patients, aged 36 to 60 years, who also underwent coronary angiography. The purpose of the study was to determine the ability of the noninvasive tests to predict multivessel coronary artery disease (CAD) and prognosis. Patients were followed up to document medical complications (incidence 12%: 3 deaths, 1 resuscitated cardiac arrest, 4 recurrent infarctions, 4 admissions with unstable angina) and combined events (medical events or bypass surgery, incidence 23%). The sensitivity, specificity and predictive accuracy for predicting multivessel CAD were 64%, 77% and 64% for a positive exercise electrocardiographic (ECG) response, 64%, 88% and 80% for a remote thallium defect, and 42%, 96% and 88% for a combination of the 2 tests. With 2 tests yielding negative findings the probability of multivessel CAD was 13%. No variable (positive exercise ECG response, remote thallium defect and presence of multivessel CAD) predicted medical events, although there were nonsignificant trends to more events in patients with any of those findings. The relative risk of combined events was 2.5 (p less than 0.05) for a positive exercise ECG response; 1.8 (NS) for a remote thallium defect; 2.6 (p less than 0.05) for multivessel CAD; and 3.1 (p less than 0.025) for both positive ECG response and remote defect. A combination of exercise electrocardiography and thallium scanning early after acute myocardial infarction helps to identify subsets of patients with high and low probabilities of multivessel CAD and combined medical or surgical events.     

Sequential multivessel coronary angioplasty assessed by thallium-201 tomography

In 11 patients with multivessel coronary artery disease, SPECT thallium-201 imaging was performed prior to and within 3 days after each of two sequential percutaneous transluminal coronary angioplasties on separate days designed to achieve total revascularization. Thallium-201 SPECT was analyzed quantitatively, and an ischemic score for the vascular bed(s) supplied by the dilated vessel(s) was derived. For the vessels dilated during the first procedure the mean diameter stenosis was 80 +/- 8%, reduced to 27 +/- 9%. For the second procedure mean stenosis was reduced from 67 +/- 10% to 26 +/- 6%. For the two procedures, the mean thallium scores decreased from 298 +/- 225 to 115 +/- 130 (P less than .001) and from 135 +/- 129 to 46 +/- 60 (P less than .001), respectively. Of 10 patients with abnormal thallium-201 SPECT prior to angioplasty, nine improved after the first procedure, and seven improved further following the second procedure. Thus, utilizing staged angioplasty with a strategy of dilating the most severe lesion first, thallium-201 SPECT documented progressive improvement in myocardial perfusion.     

Quantitative comparison of thallium-201 scintigraphy after exercise and dipyridamole in coronary artery disease

Data comparing myocardial thallium-201 imaging after exercise and intravenous dipyridamole infusion in the same patients are scarce. Accordingly, this study is a segment-by-segment quantitative analysis of regional uptake and washout of thallium-201 after dipyridamole (0.56 mg/kg) and symptom-limited exercise testing in 21 patients (ages 58 +/- 9.2 years) with chest pain studied 2.5 +/- 1.0 weeks apart. Thallium-201 activity in 9 myocardial segments was measured in initial and delayed anterior and 45 degree left anterior oblique views, producing 184 pairs of segments in the distribution of 63 coronary supply regions for direct comparison. The number of segments with normal thallium-201 uptake and the number of numerically significant defects were similar with exercise and dipyridamole (76 vs 73%, 24 vs 27%, respectively, difference not significant). A slightly higher proportion of redistribution defects was found after dipyridamole infusion compared to exercise (17 vs 10%, p less than 0.05). Agreement between 87% (165 of 189) of segment pairs was found when each was classified as either normal or abnormal. Although 24 of 189 segments were discordant, agreement was observed in 92% (61 of 63) of coronary supply regions determined to be normal (41 of 41) or abnormal (20 of 22). In 15 patients who underwent cardiac catheterization, exercise and dipyridamole-thallium-201 scintigraphy detected 61% (16 of 26) vs 61% (16 of 26) of stenoses greater than 50% (difference not significant) and 100% (19 of 19) vs 100% (19 of 19) (difference not significant) normal vessels, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Identification of multivessel coronary artery disease by exercise echocardiography

Objectives. This study examined the ability of exercise echocardiography to identify multivessel coronary artery disease and ascertain its incremental value when combined with clinical and exercise test variables.Background. Although exercise echocardiography has been shown to be accurate for the detection of coronary artery disease, little is known about its utility for identifying multivessel involvement, and its incremental value when combined with clinical and exercise test variables has not been studied.Methods. One hundred fifty consecutive patients were selected on the basis of having had an exercise echocardiographic and a coronary angiographic study within 6 months without any revascularization procedure. Significant coronary artery disease (≥50% diameter stenosis in any major coronary artery) was present in 117 patients, and multivessel (two- or three-vessel) disease was present in 90 patients. The exercise echocardiographic studies were reviewed by an experienced observer unaware of the results of the coronary angiogram.Results. The overall sensitivity and specificity of exercise echocardiography for the identification of multivessel disease were 73% and 70%, respectively. A stepwise logistic regression analysis identified the number of abnormal regions on the postexercise images as the strongest independent predictor of multivessel disease; also significant were a history of myocardial infarction and ST segment depression of at least 2 mm on the peak exercise electrocardiogram.Conclusions. Exercise echocardiography adds independent and incremental information to clinical and exercise test variables for identifying multivessel coronary artery disease.     

The usefulness of preoperative exercise stress myocardial single photon emission CT with thallium-201 to predict the responses to coronary revascularization

To evaluate the usefulness of preoperative exercise stress (Ex) myocardial single photon emission CT (SPECT) with thallium-201 to predict the responses to coronary revascularization (CRV), Ex-SPECT's were obtained in 42 patients with coronary artery disease (CAD). In 34 patients angioplasty was performed and in 18 patients coronary bypass surgery was undergone. Before and after CVR, Ex-SPECT's were obtained both at immediately after Ex (Initial) and 3 hours later (RD) by the rotating gamma camera. Initial images before CRV showed definite perfusion defects (+3) in 76 myocardial segments. Perfusion abnormalities at RD images were graded into 4 (+3 to 0) by visual interpretation. "+3" indicated fixed defect and "0" indicated no perfusion abnormality. At RD images 17 segments showed fixed defect and 59 segments showed improved perfusion more than one grade. After CRV, all 59 segments with improved perfusion at RD images showed improvement of perfusion in comparison with initial images before CRV. Out of 17 segments with fixed defect before CRV, 14 segments showed perfusion defect with +3, while 3 segments showed improved perfusion after CRV. These 3 segments had ECG evidence of myocardial infarction. In these 3 segments, Ex-SPECT's before CRV showed abnormally low myocardial T1 washout rate (WOR) despite they indicated fixed defect visually. On the contrary, other 14 segments with fixed defect showed normal WOR before CRV. In conclusion, visually interpreted Ex-SPECT's before CRV predict the myocardial perfusion after CRV in most of cases.2+n a small     

The pacing stress test: thallium-201 myocardial imaging after atrial pacing. Diagnostic value in detecting coronary artery disease compared with exercise testing

Many patients suspected of having coronary artery disease are unable to undergo adequate exercise testing. An alternate stress, pacing tachycardia, has been shown to produce electrocardiographic changes that are as sensitive and specific as those observed during exercise testing. To compare thallium-201 imaging after atrial pacing stress with thallium imaging after exercise stress, 22 patients undergoing cardiac catheterization were studied with both standard exercise thallium imaging and pacing thallium imaging. Positive ischemic electrocardiographic changes (greater than 1 mm ST segment depression) were noted in 11 of 16 patients with coronary artery disease during exercise, and in 15 of the 16 patients during atrial pacing. One of six patients with normal or trivial coronary artery disease had a positive electrocardiogram with each test. Exercise thallium imaging was positive in 13 of 16 patients with coronary artery disease compared with 15 of 16 patients during atrial pacing. Three of six patients without coronary artery disease had a positive scan with exercise testing, and two of these same patients developed a positive scan with atrial pacing. Of those patients with coronary artery disease and an abnormal scan, 85% showed redistribution with exercise testing compared with 87% during atrial pacing. Segment by segment comparison of thallium imaging after either atrial pacing or exercise showed that there was a good correlation of the location and severity of the thallium defects (r = 0.83, p = 0.0001, Spearman rank correlation). It is concluded that the location and presence of both fixed and transient thallium defects after atrial pacing are closely correlated with the findings after exercise testing.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of exercise radionuclide angiocardiography and thallium-201 myocardial perfusion imaging in coronary artery disease

First pass radionuclide angiocardiography and thallium-201 myocardial perfusion imaging were performed at rest and during exercise in 48 patients with chest pain: 39 with angiographically documented coronary artery disease and 9 with normal coronary arteries. Maximal graded upright bicycle exercise was used for both studies to assure identical exercise conditions. All nine patients without coronary artery disease had normal exercise thallium images, normal exercise regional wall motion and at least a 5 percent absolute increase in left ventricular ejection fraction during exercise (normal exercise left ventricular reserve). Ischemic S-T segment depression was demonstrated in 17 (44 percent) of the 39 patients with coronary artery disease. Findings on the two exercise tests were concordant in all cases. New or augmented thallium perfusion defects were detected in 24 (62 percent) of the 39 patients, whereas abnormal exercise left ventricular reserve was present in 33 (85 percent) (p <0.05). There was a close concordance between exercise-induced perfusion defects and regional wall motion abnormalities. The magnitude of change in ejection fraction from rest to exercise was significantly greater in patients with an abnormal exercise thallium study than in those with a normal study (−8 ± 2 percent versus −1 ± 1 percent, p <0.05). Both radionuclide studies were abnormal In 21 (54 percent) of the 39 patients, whereas both were normal only in 3 patients, all of whom had single vessel disease. Abnormal exercise left ventricular reserve was present in 12 patients with normal exercise thallium studies.     

Diagnosis of coronary artery disease by controlled coronary vasodilation with adenosine and thallium-201 scintigraphy in patients unable to exercise

Pharmacological coronary vasodilation induced by dipyridamole is often used in association with thallium-201 myocardial scintigraphy to evaluate the presence and prognostic significance of coronary artery disease. Because dipyridamole acts by blocking the cellular uptake of adenosine, we investigated the usefulness of direct intravenous administration of adenosine, a physiological substance with an exceedingly short (less than 2 seconds) plasma half-life, to induce maximal controlled coronary vasodilation in conjunction with 201Tl scintigraphy. We studied 89 patients (44 men and 45 women; mean age, 64 +/- 10 years [SD]) who were unable to perform an exercise test and were referred for evaluation of suspected coronary artery disease. The intravenous infusion of adenosine began at an initial rate of 50 micrograms/kg/min and was increased by stepwise increments every minute to a maximal rate of 140 micrograms/kg/min. 201Tl was injected intravenously after 1 minute at the highest infusion rate, followed by immediate and delayed (4 hour) tomographic imaging. At the highest infusion rate, adenosine induced a significant (p less than 0.001) decrease in systolic (8.7 +/- 19.3 mm Hg) and diastolic (6.7 +/- 9.4 mm Hg) blood pressures as well as a significant (p = 0.0001) increase in heart rate (14.5 +/- 11.0 beats/min). Side effects occurred in 83% of the patients but resolved spontaneously within 1 or 2 minutes after discontinuing the adenosine infusion. Chest, throat, or jaw pain were the most frequent symptoms and occurred in 57% of the patients. Headache (35%) and flush (29%) were also common. Ischemic electrocardiographic changes occurred in 12% of the patients, and transient first-degree atrioventricular block occurred in 10%.(ABSTRACT TRUNCATED AT 250 WORDS)     

Additional value of thallium-201 SPECT to a conventional exercise test for the identification of severe coronary lesions after an episode of unstable coronary artery disease

The additional value of thallium-201 SPECT to a conventional exercise test for the identification of patients with severe coronary lesions was evaluated in 170 men, one month after an episode of unstable coronary artery disease. Severe coronary lesions at coronary angiography — defined as three vessel disease, left main stenosis or proximal left anterior descending artery stenosis as part of two vessel disease — were observed in 45.9%. In the SPECT image, the left ventricular myocardium was divided into nine segments and each segment was classified as either normal (=0), reduced uptake (=1) or uptake defect (=2). The sum of gradings in all segments post-exercise was denoted SPECT score. The patients were divided into nine different groups regarding ST-depression during exercise (no ST-depression, ST-depression in 1–2 leads or 3 leads) and SPECT score (no SPECT score, 1–3 scores or 4 scores). Severe coronary lesions were, in 68% identified by SPECT score 4 and in 65% by ST-depression in 1 lead at exercise test. The specificity for identification of severe coronary lesions was, for both tests, 65%. SPECT score 4 and/or ST-depression in 3 leads identified 82% of the patients with severe coronary lesions with a specificity of 63%. Furthermore, SPECT score 3 identified more patients with isolated proximal left anterior descending artery stenosis than ST-depression alone at exercise test.     

Incomplete revascularization in multivessel percutaneous transluminal coronary angioplasty: the role for stress thallium-201 imaging

Evaluation of patients with multivessel coronary disease for percutaneous transluminal coronary angioplasty raises the question: Is incomplete revascularization an acceptable procedure in these patients, or does complete revascularization need to be performed, as in coronary artery bypass grafting? To provide an answer the present study utilized exercise thallium imaging as a guide to the performance of angioplasty in 85 patients with multivessel coronary disease. Preangioplasty exercise thallium imaging helped to identify the primary stenosis ("culprit lesion") in 93% of patients. Two weeks to 1 month after dilation of this lesion, repeat thallium imaging identified two patient groups: Group 1, 47 patients with no evidence of ischemia in a second vascular distribution and Group 2, 38 patients with evidence of further angioplasty. In Group 2 47% of patients had angioplasty of a second vessel and 79% required multivessel angioplasty at 1 year follow-up. In contrast, only six Group 1 patients (13%) required angioplasty of a second vessel at 1 year. Thus, incomplete revascularization may be an acceptable approach in many patients with multivessel coronary disease. Stress thallium-201 imaging may be a useful technique in the evaluation and management of these patients.     

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)     

Increased exercise thallium-201 lung uptake: a noninvasive prognostic index in two-vessel coronary artery disease

To determine the physiologic impact of two-vessel coronary artery disease and its effect on prognosis, a series of clinical, angiographic, exercise and quantitative thallium-201 (Tl-201) imaging parameters were analyzed in 85 consecutive two-vessel coronary artery disease patients followed for 52 +/- 27 months after coronary angiography and Tl-201 scintigraphy. End points were cardiac death (n = 3), myocardial infarction (n = 6) and coronary bypass graft surgery more than three months after testing (n = 16). Using Cox Hazards survival analysis, early cardiac events were not predicted by: myocardial infarction or anginal history; resting left ventricular function; exercise blood pressure response; angina or severity of ECG ST segment depression (mm); Tl-201 defect size; redistribution or clearance; angiographic patterns; or the presence of proximal left anterior descending disease. Significant predictors of adverse cardiac events were: increased exercise lung to heart Tl-201 ratio (0.59 +/- 0.12 versus 0.46 +/- 0.1; P less than 0.0001); ECG lead extent of ST segment depression (P less than 0.03); and exercise heart rate response (P less than 0.047). Event-free survival for patients with normal and abnormally increased lung to heart Tl-201 ratios at 48 months was 76% versus 63% (P less than 0.003). It was concluded that two-vessel coronary artery disease survival correlates with exercise Tl-201 uptake which reflects exercise induced left ventricular dysfunction.