Predictors of prognosis by quantitative assessment of coronary angiography, single photon emission computed tomography thallium imaging, and treadmill exercise testing.
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Aged↗
Biomedical subjects
V Cave
Publications and source records attributed to V Cave.
Comparison of the Bruce and ramp protocols in the assessment of left ventricular performance during exercise in healthy women.
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Cardiac Output↗
Serial changes in left ventricular function after coronary artery bypass: implications in viability assessment.
Improvement in left ventricular (LV) performance after coronary artery bypass surgery remains the gold standard in myocardial viability assessment. The time-related changes, however, are not well known. This study examined the LV ejection fraction (EF) by gated blood pool imaging early (6 +/- 4 days) and late (62 +/- 24 days) after surgery in patients with normal preoperative EF (group 1, n = 12) and those with LV dysfunction (group 2, n = 15). There were no changes in the clinical status between the early and late studies, and all patients had normal sinus rhythm. Group 1 had no significant change in EF (preoperatively 62%, early postoperatively 64%, late postoperatively 63%; p = NS). In group 2, EF was 26% +/- 8% preoperatively; 30% +/- 10% early postoperatively; and 34% +/- 8% late postoperatively (p < 0.05). Postoperatively there was > or = 5% improvement in EF in 4 patients early and 11 patients late (p < 0.05). Patients who showed early improvement continued to do so in the late study but, additionally, 7 patients showed improvement only in the late study. Thus the timing of EF measurement after surgery is important in patients with LV dysfunction but not in patients with normal LV function. Early assessment may underestimate the prevalence and degree of recovery.
Aged↗
Results of adenosine single photon emission computed tomography thallium-201 imaging in hemodynamic nonresponders.
Systolic blood pressure typically decreases during adenosine infusion because of stimulation of A2b receptors, resulting in systemic vasodilation. This study examined the results of adenosine single photon emission computed tomography (SPECT) thallium-201 imaging in patients who did not show such a decrease in blood pressure during peak adenosine effect (nonresponders). The 102 nonresponders and 341 responders had no significant differences in age, gender, history of diabetes mellitus, hypertension, or previous myocardial infarction. The extent of coronary artery disease (CAD) by angiography was also similar. The sensitivity of SPECT thallium-201 imaging in patients with one-vessel disease was 82% in nonresponders and 84% in responders (p value not significant [NS]); in patients with multivessel disease, it was 90% in nonresponders and 94% in responders (p = NS) and for all CAD, it was 87% in non-responders and 91% in responders (p = NS). Thus lack of hemodynamic systemic response during adenosine infusion does not affect sensitivity for detecting CAD.
Adenosine↗
Study of myocardial infarct remodeling by single-photon emission computed tomographic imaging.
Left ventricular (LV) remodeling after Q-wave anterior acute myocardial infarction (AMI) was examined with single-photon emission computed tomographic thallium imaging. Initial (after adenosine infusion) and 4-hour delayed reinjection images were obtained in 34 patients aged 65 +/- 12 years. Short-axis slices from the delayed images were quantitatively analyzed by measuring the outer and inner diameters, and wall thickness. The results were compared with those in a group of normal subjects. The outer diameter was greater in patients than in normal subjects at the apical, mid- and basal levels (all p < 0.01); the average outer diameter was 16.9 +/- 1.9 mm in patients, and 12.2 +/- 1.3 mm in normal subjects (p < 0.001). Similarly, the inner diameter was greater in patients than in normal subjects at the 3 levels (all p < 0.05); the average inner diameter was 6.5 +/- 1.8 mm in patients, and 4.7 +/- 1.3 mm in normal subjects (p < 0.01). Wall thickness was greater in patients than in normal subjects (5.2 +/- 0.5 vs 3.8 +/- 0.5 mm; p < 0.0001). There were significant correlations between LV dilation and time elapsed (in weeks) since AMI (r = 0.57; p < 0.005), and the size of the perfusion abnormality (r = 0.44; p < 0.03). Thus, LV dilation occurs after Q-wave anterior AMI, and is related to infarct size and duration. These changes can be studied by single-photon emission computed tomographic thallium imaging.
Adenosine↗
Identification of high-risk patients with left main and three-vessel coronary artery disease by adenosine-single photon emission computed tomographic thallium imaging.
The purpose of this study was to examine the ability of SPECT imaging with thallium-201 during adenosine-induced coronary hyperemia to detect high-risk patients with left main or three-vessel CAD. There were 339 patients: 102 with either left main or three-vessel CAD (group 1) and 237 with no CAD, one-, or two-vessel disease (group 2). By means of univariate analysis, several variables were found to differ between groups 1 and 2: Q wave myocardial infarction (35% vs 25%, p < 0.05), ST segment depression (35% vs 19%, p < 0.001), age (67 +/- 9 vs 62 +/- 10 years, p < 0.001), resting systolic blood pressure (142 +/- 22 vs 135 +/- 20 mm Hg, p < 0.01), abnormal thallium images (95% vs 74%, p < 0.0001), multivessel thallium abnormality (76% vs 39%, p < 0.0001), extent of thallium abnormality (24 +/- 11% vs 19 +/- 13%, p < 0.0001), and increased lung thallium uptake (39% vs 15%, p < 0.01). According to stepwise discriminant analysis, only three variables were predictors of high risk: multivessel thallium abnormality (chi 2 = 27), increased lung thallium uptake (chi 2 = 10), and ST depression (chi 2 = 5). On the basis of these variables, patients were divided into three groups with different prevalence rates for left main and three-vessel CAD: 63% in 68 patients, 30% in 137 patients, and 13% in 137 patients.(ABSTRACT TRUNCATED AT 250 WORDS)
Adenosine↗
Simultaneous assessment of left ventricular perfusion and function with technetium-99m sestamibi after coronary artery bypass grafting.
This study examined the left ventricular perfusion and EF by using simultaneous SPECT and first-pass radionuclide angiography with technetium 99m sestamibi in 95 patients after uncomplicated coronary artery bypass grafting. The patients were divided into those with normal EF and no previous myocardial infarction before surgery (group 1, n = 57), and those with abnormal EF or infarction (group 2, n = 38). The SPECT images were normal in 37 patients in group 1 and in 6 patients in group 2 (p < 0.0001). The patients with normal SPECT images had a higher EF after surgery than those with abnormal images (65% +/- 10% vs 50% +/- 14%, p < 0.0001) and was higher in group 1 than in group 2 (64% +/- 8% vs 46% +/- 16%, p < 0.0001). There was a significant correlation between the EF and the extent of perfusion abnormality (r = -0.44, p < 0.0001). The patients with normal SPECT images could not be separated from those with abnormal images based on peak CK, CK-MB, and the electrocardiographic changes. Of the 69 patients with postoperative EF > or = 50%, the perfusion pattern was normal in 41 and abnormal in 28; of the 26 patients with EF < 50%, 24 had abnormal SPECT (p < 0.003). There was no significant change in mean EF after surgery (55% +/- 14% before vs 56% +/- 15% after). Thus simultaneous assessment of left ventricular perfusion and function after coronary artery bypass grafting showed that an abnormal perfusion pattern may exist despite a normal EF. These patients could not be predicted by enzymes or electrocardiographic changes.
Aged↗
Independent and incremental prognostic value of exercise single-photon emission computed tomographic (SPECT) thallium imaging in coronary artery disease.
OBJECTIVES: The objective of this study was to examine the independent and incremental prognostic value of exercise single-photon emission computed tomographic (SPECT) thallium imaging in patients with angiographically defined coronary artery disease. BACKGROUND: Previous studies showed the importance of exercise thallium-201 in risk stratification. However, most of these studies used planar imaging techniques. METHODS: Follow-up data were obtained in 316 medically treated patients with coronary artery disease. Cox proportional hazards regression models were used to examine the independent and incremental prognostic values of clinical, exercise, thallium and cardiac catheterization data. RESULTS: There were 35 events (cardiac death or nonfatal myocardial infarction) at a mean follow-up time of 28 months. Univariate analysis showed that gender (chi-square = 5.1), exercise work load (chi-square = 3.1), extent of coronary artery disease and left ventricular ejection fraction (chi-square = 14.8) and thallium variables (chi-square = 22.7) were prognostically important. The thallium data provided incremental prognostic value to catheterization data (chi-square = 33.7, p < 0.01). The extent of the perfusion abnormality was the single best predictor of prognosis (chi-square = 14). Patients with a large perfusion abnormality had a worse prognosis than that of patients with a mild or no abnormality (Mantel-Cox statistics = 10.6, p < 0.001). CONCLUSIONS: In medically treated patients with coronary artery disease, exercise SPECT thallium imaging provides independent and incremental prognostic information even when catheterization data are available. The extent of the perfusion abnormality is the single most important prognostic predictor.
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Identification of extensive coronary artery disease in women by exercise single-photon emission computed tomographic (SPECT) thallium imaging.
OBJECTIVES: The aim of this study was to examine the ability of exercise single-photon emission computed tomographic (SPECT) thallium imaging to identify high risk women with left main or three-vessel coronary artery disease using a stepwise discriminant analysis. BACKGROUND: Previous studies have used statistical methods to identify high risk men with coronary artery disease. Only limited data are available in women. METHODS: Exercise SPECT thallium imaging and coronary arteriography were performed for evaluation of chest pain in 243 women. Group 1 comprised 58 women with left main or three-vessel coronary disease and group 2 comprised 185 women with no or one- or two-vessel disease. Stepwise discriminant analysis was used to determine predictors of left main or three-vessel disease. RESULTS: On univariate analysis, women in group 1 were older (p < 0.03) and had a lower exercise work load (p < 0.02), lower exercise heart rate (p < 0.004), higher prevalence rate of diabetes mellitus (p < 0.0003) and more multivessel thallium abnormality (p < 0.0001) compared with women in group 2. On multivariate analysis, only multivessel thallium abnormality (F = 43) and exercise heart rate (F = 6) were independent predictors of left main or three-vessel coronary disease. A model based on these two variables separated the women into three risk groups: 99 patients with 9%, 70 patients with 23% and 74 patients with 45% prevalence of left main or three-vessel disease (p < 0.0001). CONCLUSIONS: High risk women with left main or three-vessel coronary disease can be identified by exercise SPECT thallium imaging.
Aged↗
Age- and sex-related differences in the use of coronary angiography in patients undergoing adenosine SPECT thallium imaging.
BACKGROUND: Recent reports suggest sex-related differences in the management of patients with coronary artery disease. METHODS: This study examined the pattern of use of coronary angiography in 535 patients initially referred for adenosine single photon emission computed tomography (SPECT) thallium imaging. RESULTS: Coronary angiography was carried out more often in patients under 70 years of age than those over 70 years of age [107 out of 322 (33%) versus 50 out of 213 (23%), P < 0.01]. Even in patients with abnormal adenosine SPECT thallium results, coronary angiography was less frequently performed in the elderly [40 out of 130 (31%) versus 82 out of 178 (46%), P < 0.01]. Women underwent coronary angiography less often than men [56 out of 261 (21%) versus 101 out of 274 (37%), P < 0.0002]. This difference was due to differences in patients under 70 years of age [31 out of 138 women (22%) versus 76 of 184 men (41%), P < 0.003)], but not in patients over 70 years of age. In patients with abnormal adenosine thallium image results, the difference between men and women was still present: 37 out of 112 women (33%) versus 85 of 196 men (43%) underwent coronary angiography (P = 0.05). Stepwise discriminant analysis of clinical and scintigraphic variables identified four independent predictors of the need for coronary angiography; the abnormal thallium image results (chi 2 = 33, P < 0.0001); the size of the perfusion abnormality (chi 2 = 7, P < 0.01); sex (chi 2 = 7, P < 0.01) and age (chi 2 = 4, P < 0.05). CONCLUSION: Coronary angiography is less often performed in women and elderly patients even when initial screening results are abnormal. The relation of this observation to subsequent clinical course and events requires further studies.
Adenosine↗
Mechanism of exercise-induced hypotension in coronary artery disease.
Hypotension during exercise testing has been considered a marker of extensive coronary artery disease (CAD) and poor prognosis. The mechanism of hypotension was examined in 25 CAD patients who developed hypotension during treadmill exercise testing (mean decrease in systolic blood pressure [BP] 33 +/- 13 mm Hg) (group 1) and was compared with the results of 25 CAD patients who had a normal systolic BP response to exercise (mean increase 53 +/- 15 mm Hg) (group 2). The 2 groups were comparable in age, sex, extent of CAD, previous myocardial infarction, left ventricular ejection fraction, history of hypertension and cardiac medications. Exercise heart rate (121 +/- 23 vs 133 +/- 25 beats/min; p = not significant [NS]) and duration (6 +/- 2 vs 7 +/- 3 minutes; p = NS) were comparable. ST-segment depression occurred in 44% of patients in group 1 and in 52% in group 2 (p = NS), and angina during exercise occurred in 60% of both groups. Single-photon emission computed tomographic thallium images were abnormal in 24 patients (96%) in group 1 and in 20 patients (80%) in group 2 (p = NS). Percent thallium abnormality was 19 +/- 12% in group 1, and 18 +/- 14% in group 2 (p = NS), and the severity of thallium abnormality was 710 +/- 510 in group 1, and 510 +/- 500 in group 2 (p = NS). Ischemia involving the inferior/posterior segments was seen in 68% of patients in group 1 and in 60% in group 2 (p = NS). Increased lung thallium uptake was seen in 48% of both groups.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
The perfusion pattern in coronary artery occlusion: comparison of exercise and adenosine.p6.
This study compared exercise to adenosine thallium-201 single photon emission computed tomography in detecting occlusion of left anterior descending or right coronary arteries in patients with no previous myocardial infarction. There were 41 patients who underwent adenosine thallium imaging (adenosine infusion at a rate of 140 micrograms/kg/min for 6 min), and 143 patients who underwent exercise thallium imaging. There were more patients with right coronary than left anterior descending coronary artery occlusion. Thus, in the adenosine group, there were 15 patients with left anterior descending artery occlusion, and 26 with right coronary artery occlusion, and in the exercise group, there were 46 patients with left anterior descending artery occlusion, and 97 patients with right coronary artery occlusion. In the adenosine group, the thallium images were abnormal in 41 patients (100%), while in the exercise group, the thallium images were abnormal in 125 patients (87%, P < 0.02) in the territories of the occluded arteries. ST segment depression was noted in 19 patients (46%) in the adenosine group, and 69 patients (48%) in the exercise group (P:NS). In patients with isolated single vessel occlusion, the size of the perfusion abnormality was 28 +/- 9% with adenosine, and 21 +/- 12% with exercise (P:NS). Thus, most patients with occlusion of the left anterior descending or right coronary artery have regional perfusion abnormality during stress; the different role of collaterals with each type of stress may explain the higher percentage of abnormal results with adenosine than exercise.
Adenosine↗
The treadmill exercise score revisited: coronary arteriographic and thallium perfusion correlates.
The treadmill exercise score has been used to stratify patients into low-, moderate-, and high-risk groups. This score is derived from ST segment depression, angina, and exercise duration. To determine the coronary arteriographic and exercise thallium perfusion correlates of the score, we examined the extent of coronary artery disease and exercise single photon emission computed thallium-201 results in 834 patients for whom cardiac catheterization data were available. Of those, 174 had no coronary artery disease, 195 had one-vessel, 246 had two-vessel, and 219 had three-vessel disease. Based on the treadmill exercise score, 369 were in the low-risk, 384 in the moderate-risk, and 81 in the high-risk group. The extent of coronary artery disease was 2.1 +/- 1 diseased vessels in the high-risk, 1.7 +/- 1 in the moderate, and 1.4 +/- 1.1 in the low-risk group (p < 0.01). The extent of the thallium abnormality (maximum number of abnormal segments 120/patient) was 10 +/- 6 in the high-risk, 7 +/- 6 in the moderate, and 6 +/- 5 in the low-risk group (p < 0.05). Based on the extent of coronary artery disease and results of thallium imaging, patients were reclassified into three groups: group 1 had three-vessel disease and/or > or = 10 abnormal segments (n = 387), group 3 had no coronary artery disease or one-vessel disease and less than five abnormal segments (n = 212), and the remaining patients were in group 2 (n = 235).(ABSTRACT TRUNCATED AT 250 WORDS)
Aged↗
Single photon emission computed tomographic teboroxime imaging with a preprocessing masking technique.
We previously reported that single-head SPECT imaging with teboroxime is feasible. However, excessive hepatic uptake in some patients may interfere with image interpretation. This study examined the feasibility of improving image quality by use of a preprocessing masking technique to subtract hepatic activity. A band of 10 pixels in width adjacent to the inferior cardiac silhouette was marked on the raw planar images, and then SPECT reconstruction was done with the Butterworth filter with a frequency cutoff of 0.3 cycles/cm and the power of 10. The stress and rest images were compared before and after masking in 10 patients who underwent SPECT teboroxime imaging during adenosine-induced coronary hyperemia (140 micrograms/kg/min for 6 minutes). SPECT imaging with a single-head detector was performed with the use of a 180-degree anterior arc (from the 45-degree left posterior oblique projection to the 45-degree right anterior oblique projection); 32 images at 8 seconds per stop were obtained (total imaging time = 6.8 minutes). All images were considered subjectively better after the masking technique was used, especially for assessment of inferior wall perfusion pattern. The maximum count in any pixel was in the hepatic region of interest before masking and in the cardiac region of interest after masking (303 +/- 110 counts vs 166 +/- 55 counts; p < 0.001). The difference was especially pronounced in the images that were obtained when patients were at rest (366 +/- 102 counts vs 184 +/- 64 counts; p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
Adenosine↗
Side effects during adenosine thallium imaging with single-port or double-port infusion protocols.
The double-port infusion protocol during adenosine thallium imaging involves the use of two infusion systems, one for adenosine and one for thallium. The single-port infusion protocol, on the other hand, uses one infusion system; both adenosine and thallium are injected via a "Y" connection. This study examined the possibility that the single infusion system, by displacing a column of blood filled with adenosine, may be responsible for a greater incidence of side effects. In a parallel study, 140 patients underwent adenosine thallium imaging with the single-port system (group 1) and 140 patients underwent imaging with the double-port system (group 2). Both groups were comparable in age (67 +/- 10 years vs 64 +/- 11 years), gender (men comprised 56% of patients in group 1 and 64% in group 2), resting heart rate, and systolic blood pressure. More patients in group 1 had chest pains (57% vs 44%; p = 0.03), ST-segment depression (25% vs 9%; p = 0.005), nausea (11% vs 4%; p = 0.04), and second- or third-degree atrioventricular block (11% vs 5%; p less than 0.08) than did patients in group 2. The other side effects were similar, and peak heart rate and peak systolic blood pressure were also similar. The thallium images that used single-photon emission computed tomography were abnormal in 61% of patients in group 1 and in 65% of patients in group 2 (p = not significant).(ABSTRACT TRUNCATED AT 250 WORDS)
Adenosine↗
Atrioventricular block during adenosine thallium imaging.
Transient atrioventricular (AV) block has been reported during adenosine thallium imaging. This study examined the predictors and hemodynamic implications in 55 patients who had second- or third-degree AV block (group 1) and compared the results with those in 803 patients who did not have AV block (group 2). There were no significant differences in age, sex, or heart rate at baseline between the two groups. ST segment depression was observed in 25% of patients in group 1 and 16% in group 2 (p = NS). Chest pain occurred in 56% in group 1 and 44% in group 2 (p = NS). Preexisting conduction abnormalities (17% vs 16%) and treatment with digitalis (15% vs 15%) and beta-blockers (31% vs 36%) were similar in the two groups. The results of thallium imaging were abnormal in 66% in group 1 and 67% in group 2 (p = NS). Reversible thallium defects were seen in 51% in group 1 and 52% in group 2 (p = NS). The AV block appeared during the first 2 minutes of infusion in 40 patients (73%) and disappeared despite continuation of infusion in 43 (78%). The heart rate during AV block was 79 +/- 18 beats/min, and the systolic blood pressure was 127 +/- 27 mm Hg. Premature termination of adenosine infusion was required in one patient (2%). Aminophylline was used in 5% in group 1 and 2% in group 2 (p = NS). Thus AV block is transient, occurs during the early minutes of infusion, is not aggravated by digitalis or beta-blocker therapy, can be seen in patients with normal perfusion images, and is often well tolerated.
Adenosine↗
Tomographic myocardial perfusion imaging with technetium-99m teboroxime during adenosine-induced coronary hyperemia: correlation with thallium-201 imaging.
Single-photon emission computed tomographic imaging with technetium-99m teboroxime during exercise has been found to be feasible and the results correlate with those obtained with thallium-201. This study examined the feasibility of this technique and compared tomographic imaging with technetium-99m teboroxime during adenosine-induced coronary hyperemia with thallium-201 imaging. With the patient positioned on the imaging table, adenosine was infused at a rate of 140 micrograms/kg per min for 6 min. At 4 min, 20 to 25 mCi (740 to 925 MBq) of technetium-99m teboroxime was injected intravenously and imaging was started as soon as the infusion was completed with use of a 180 degrees anterior arc and 32 stops at 10 s/stop (total imaging time 7.8 min). Rest images were obtained 60 to 90 min later with use of a similar dose of technetium-99m teboroxime. Exercise tomographic thallium images were obtained within 2 weeks of the teboroxime studies. In the 20 patients studied, the teboroxime images were normal in 2 (50%) of 4 normal subjects and abnormal in 15 (94%) of 16 patients with coronary artery disease; 4 of the 15 had a fixed defect and 11 a reversible defect. There was agreement between teboroxime and thallium studies in 16 patients (80%), in 319 (80%) of 400 segments and in 50 (83%) of 60 vascular segments (p less than 0.05). In two normal subjects, an apparent fixed defect involving the inferior wall was seen on the teboroxime but not the thallium images and was thought to be due to an attenuation artifact secondary to extracardiac activity in the left lobe of the liver.(ABSTRACT TRUNCATED AT 250 WORDS)
Adenosine↗
Early thallium imaging after percutaneous transluminal coronary angioplasty: tomographic evaluation during adenosine-induced coronary hyperemia.
This study examined the immediate results of 201Tl imaging during adenosine-induced coronary hyperemia in 25 patients with one-vessel coronary artery disease, 4 +/- 3 days after percutaneous transluminal coronary angioplasty (PTCA). There were special features in our study: use of quantitative angiography and single-photon emission computed tomography (SPECT); a homogeneous group of patients (one-vessel disease) and a uniform stress (adenosine infusion). As a group, quantitative coronary angiography showed a decrease in percent diameter stenosis from 72% +/- 12% to 23% +/- 14%, p < 0.001. The thallium images were normal in 17 patients and abnormal in eight patients. However, of the eight patients, four had residual stenosis either in a secondary branch or downstream; one patient had local dissection (the residual stenosis could not be assessed reliably), two patients had > 50% residual diameter stenosis, and one patient had previous Q-wave myocardial infarction with a corresponding fixed thallium defect. In each of the eight patients with an abnormal image, a logical explanation could be identified. Thus, our results suggest that maximum reactive coronary hyperemia returns to normal immediately after PTCA, and that abnormal thallium results are due to inadequate dilatation or associated lesions.
Adenosine↗