The graft flow and 201Tl-myocardial scintigram in patients with saphenous vein graft or left internal thoracic artery graft

To evaluate myocardial perfusion in patients with saphenous vein graft (SVG) or internal thoracic artery graft (ITA-G), we studied 38 patients (14: SVG, 10 males and 4 females, mean age 66 +/- 9 y-o; 24: ITA-G, 18 males and 6 females, mean age 64 +/- 7 y-o) by digital subtraction angiography (DSA) of ITA-G or SVG, and thallium-201 myocardial perfusion scintigraphy on exercise or dipyridamole stress. The grafting sites were left anterior descending artery (LAD) in all patients. Normal controls (n = 22) were defined by normal coronary angiogram and no evidence of myocardial ischemia. The graft flow and flow reserve on dipyridamole were measured by Rutishauser's formula. The basal blood flow of native normal ITA, SVG and ITA-G were respectively 72 +/- 24 ml/min, 51 +/- 23 ml/min, and 36 +/- 20 ml/min. The basal ITA-G flow was significantly lower than SVG-flow (p < 0.05). The flow reserves of SVG and ITA-G were respectively 2.32 +/- 0.65 and 1.78 +/- 0.59 (p < 0.02). The incidence of moderate hypoperfusion of thallium-201 SPECT was 14.3% in SVG and 12.5% in ITA-G on exercise stress, and 35% in SVG and 50% in ITA-G on dipyridamole stress. The incidence of reversible myocardial ischemia on dipyridamole stress was significant. The graft flow in patients with normal and abnormal thallium-201 SPECT were respectively 61 +/- 21 ml/min and 33 +/- 15 ml/min in SVG (p < 0.01), 46 +/- 19 ml/min and 27 +/- 16 ml/min in ITA-G (p < 0.02). The graft flow reserve were respectively 2.69 +/- 0.38 and 1.65 +/- 0.49 in SVG (p < 0.001), 2.25 +/- 0.40 and 1.31 +/- 0.28 in ITA-G (p < 0.001). We concluded that the basal blood flow and flow reserve of ITA-G were significantly lower than those of SVG. The myocardial ischemia was occasionally documented by the thallium-201 myocardial SPECT on dipyridamole stress in patients with patent ITA-G.     

Myocardial perfusion reserve studied by single-photon emission-computed tomography with thallium-201 and a drug stress test with adenosine triphosphate in patients with cardiovascular risk factors

INTRODUCTION AND OBJECTIVE: Recent studies have suggested that the evaluation of coronary reserve is a sensitive method in the early detection of vascular alterations before plaques exist, and certainly before clinical detection of atherosclerotic lesions. Single-photon emission-computed tomography (SPECT) with thallium-201 (201Tl) provides a noninvasive tool for evaluating myocardial perfusion reserve. The objective of this study was to measure the myocardial perfusion reserve in two groups of subjects, some with and some without cardiovascular risk factors and in a group of patients with coronary artery disease. METHODS: Seventy-four subjects, divided into three groups, were recruited to assess regional and global myocardial perfusion reserve. The control group consisted of 11 asymptomatic individuals without cardiovascular risk factors. The second group was composed of 49 patients with one or more risk factors. Finally, the third group included 14 patients with coronary artery disease. 201Tl-SPECT at rest and after pharmacological stress with a 7 minute adenosine triphosphate (ATP) infusion (140 micrograms/kg/min) was performed in all patients. ATP minus rest value subtraction was applied in order to obtain the stress data. Relative myocardial perfusion reserve indices were calculated as the ratio between stress and rest values. RESULTS: Global and regional myocardial perfusion reserves of the vascular territories were significantly lower in patients with cardiovascular risk factors than in control subjects (Global: 1.48 +/- 0.19 vs 1.81 +/- 0.08, LAD: 1.52 +/- 0.21 vs 1.85 +/- 0.09, CX: 1.45 +/- 0.2 vs 1.79 +/- 0.86, RCA: 1.47 +/- 0.2 vs 1.79 +/- 0.86) and higher than in patients with coronary artery disease (Global: 1.48 +/- 0.19 vs 1.31 +/- 0.14, LAD: 1.52 +/- 0.21 vs 1.35 +/- 0.15, CX: 1.45 +/- 0.2 vs 1.2 +/- 0.24). Univariate linear regression analysis in a group of 40 patients with high risk lipid profiles revealed a significant negative correlation between myocardial perfusion reserve and total cholesterol (r = -0.35; p = 0.01), LDL-cholesterol (r = -0.38; p = 0.036) and LDL/HDL ratio (r = -0.39; p = 0.029). CONCLUSION: Determination of myocardial perfusion reserve with 201Tl-SPECT allows the detection of abnormal vasodilatory response to intravenous ATP in patients with cardiovascular risk factors. These patients have higher reserves than patients with coronary disease, which might suggest an early phase of atherosclerosis.     

Dipyridamole and dobutamine-atropine stress echocardiography in the diagnosis of coronary artery disease. Comparison with exercise stress test, analysis of agreement, and impact of antianginal treatment

STUDY OBJECTIVES: To compare the usefulness of dipyridamole echocardiography, dobutamine-atropine echocardiography, and exercise stress testing in the diagnosis of coronary artery disease and to analyze the agreement among the tests. DESIGN: Performance of these three tests in random order on a consecutive cohort of patients. SETTING: A tertiary care and university center. PATIENTS: One hundred two consecutive patients with chest pain and no history of coronary artery disease. INTERVENTIONS: Dipyridamole echocardiography, dobutamine-atropine echocardiography, exercise stress testing, and coronary angiography. MEASUREMENTS AND RESULTS: Dobutamine-atropine test was positive in 49 (77%) of 63 patients with coronary artery disease, dipyridamole test in 49 (77%), and exercise stress test in 44 (68%; p = NS). Both echocardiographic tests showed an overall specificity (dipyridamole, 97%; dobutamine, 95%) higher than exercise stress test (79%; p < 0.05). Sensitivity of dipyridamole testing decreased from 93 to 61% (p = 0.002) if patients were receiving antianginal treatment but sensitivity of dobutamine-atropine testing was not affected (77% in patients receiving and not receiving treatment). When results were considered as positive-negative, agreement between dipyridamole and dobutamine-atropine echocardiography was 85% (kappa = 0.70). With regards to regional analysis, concordance was good (93% for segments, kappa = 0.76; and 95% for coronary arteries, kappa = 0.92). Major complications were more frequent during dobutamine-atropine (n = 7) than during dipyridamole infusion (n = 2) (p = 0.06). CONCLUSIONS: Dobutamine-atropine and dipyridamole echocardiography have a similar sensitivity and a higher specificity than that obtained by exercise ECG for the diagnosis of coronary artery disease. Similar information is obtained with dipyridamole and dobutamine-atropine echocardiography. It is our thought that pharmacologic stress echocardiography should be used as a first-step test to rule out coronary artery disease in patients not capable of exercising.     

Comparative prognostic value of clinical risk indexes, resting two-dimensional echocardiography, and dipyridamole stress thallium-201 myocardial imaging for perioperative cardiac events in major nonvascular surgery patients

The relative prognostic value of widely accessible resting two-dimensional echocardiographic ventricular function data has not been compared with recognized clinical and scintigraphic risk markers in patients who are unable to exercise before major nonvascular surgery. To this end, 53 consecutive patients aged 67 +/- 13 years undergoing preoperative evaluation (intraabdominal, 23%; orthopedic, 30%; thoracic, 9%; other, 38%) for known or suspected coronary artery disease were followed up to evaluate the prognostic value of these studies for the perioperative cardiac events (cardiac death [n = 4], myocardial infarction [n = 2], unstable angina [n = 3], and pulmonary edema [n = 8]) that occurred in 13 of the 53 patients (25%). Dipyridamole thallium-201 myocardial redistribution defects occurred in 15 (28%) patients. Resting echocardiographic left ventricular dysfunction was present in 21 (40%) patients. Multivariate analysis of clinical, echocardiographic, and scintigraphic risk predictors revealed that cardiac events were not predicted by clinical variables, including Goldman class or score. Cardiac events were independently predicted only by the presence of significant left ventricular dysfunction on resting two-dimensional echocardiography (p < 0.042) and dipyridamole thallium-201 defect redistribution (p < 0.026). A dipyridamole-induced reversible thallium-201 perfusion defect was predictive of subsequent cardiac death or myocardial infarction (p < 0.02), whereas left ventricular dysfunction on resting echocardiography was predictive of perioperative pulmonary edema (p < 0.023). We conclude that stress thallium-201 perfusion imaging and resting two-dimensional echocardiography provide independent prognostic information in patients undergoing major nonvascular surgery who are at significant risk for ischemic cardiac events and who are unable to perform standard exercise stress tests.(ABSTRACT TRUNCATED AT 250 WORDS)     

Reverse redistribution during dipyridamole thallium-201 myocardial single photon emission computed tomography in coronary artery disease

Ninety-six of the consecutive 1100 patients who underwent dipyridamole thallium-201 myocardial single photon emission computed tomography (SPECT) demonstrated reverse redistribution (RR). Twenty-six of the 96 cases who had accepted coronary angiographies were included in this study. RR was present in 40 myocardial segments from the 26 patients. Seventeen segments were in the right coronary artery (RCA) distribution, 17 in the left anterior descending artery (LAD) distribution, and 6 in the left circumflex artery (LCX) distribution. Perfusion defects noted on the initial study became more severe in the delayed images in 22 segments and normal perfusion was present during the initial images in 18 segments. Seventeen segments with RR were in the distribution of coronary arteries with abnormal angiographic findings. Of the remaining 23 segments, the angiographic findings were normal. In conclusion, RR can happen in TI -201 SPECT after dipyridamole and easily appears in the territories of RCA and LAD. It does not absolutely indicate whether the arteries are significantly diseased or normal coronary arteries.     

Experimental study of the reaction pp-->pp pi 0 in the energy range 600-900 MeV

To compare regional thallium-201 SPECT redistribution patterns with rubidium-82 PET, we studied 81 patients with both imaging modalities. Sixty patients had significant coronary artery disease. All patients underwent PET imaging after dipyridamole infusion, while SPECT imaging was performed after exercise stress (38 patients) and dipyridamole (43 patients). Sixty-eight percent of patients with prior infarct had fixed defects on SPECT, compared to 39% with PET. Sixty-one percent of patients with prior infarct had PET perfusion defects which exhibited 'reflow' or normal rubidium-82 tracer uptake (p < 0.05 vs. SPECT). Similar results were seen in patients without prior infarct (26% fixed defects on SPECT vs. 12% for PET, p < 0.05). Regional analysis showed that 57% of fixed SPECT defects corresponded to PET defects with reflow or normal rubidium-82 uptake, while 78% of 'fixed' PET defects corresponded to fixed SPECT defects. PET reflow and normal rubidium-82 uptake in sites of fixed thallium-201 SPECT perfusion defects suggest that imaging modalities employing separate tracer injections at rest and after stress, such as rubidium-82 PET, may be more specific in the assessment of myocardial viability, especially in patients with prior myocardial infarction.     

An in vitro osteotomy method to expose the medial compartment of the human knee

Dobutamine stress echocardiography (DSE) and exercise thallium-201 single-photon emission computed tomography (SPECT) were compared for the accuracy in detecting coronary artery disease (CAD) in 51 consecutive patients. Twenty-six (group 1) of the 51 patients achieved adequate exercise end points, and 25 (group 2) did not. There were 38 patients with angiographically documented CAD. The overall sensitivity of DSE and thallium-201 SPECT in detecting CAD was 92 and 76% (p = NS), and the specificity was 77 and 77% (p = NS), respectively. The sensitivity of DSE is the same as that of SPECT in group 1 (90 vs. 90%; p = NS) and higher than that of SPECT in group 2 (94 vs. 61%; p < 0.05). In patients with CAD without a history of acute myocardial infarction or pathological Q wave on resting electrocardiogram, the sensitivity of DSE is the same as that of SPECT in group 1 (82 vs. 82%; p = NS) and also higher than that of SPECT in group 2 (90 vs. 40%; p = 0.03). The sensitivity in detecting individual coronary artery lesions with DSE and thallium-201 SPECT was not affected by the exercise level. The agreement between DSE and thallium SPECT in detecting patients with CAD was 88% in group 1 (kappa = 0.69; p < 0.001) and 76% in group 2 (kappa = 0.45; p = 0.01). The agreement in detecting vascular territories with ischemia was 68% in group 1 (kappa = 0.30; p < 0.01) and 75% in group 2 (kappa = 0.33; p < 0.001). The agreement in detecting vascular territories with a scar was 87% in group 1 (kappa = 0.55; p < 0.001) and 85% in group 2 (kappa = 0.44; p < 0.001). In conclusion, the sensitivity and specificity of DSE in detecting CAD are similar to that of thallium-201 SPECT with an exercise level > or =85% of the maximal predicted heart rate. However, in patients who cannot exercise adequately, DSE is more accurate than thallium SPECT. The agreement between DSE and thallium SPECT in detecting patients with CAD and identifying ischemia of individual vascular territories is also affected by the exercise level.     

Comparison between thallium-201 and technetium-99m-tetrofosmin uptake with sustained low flow and profound systolic dysfunction

Technetium-99m-tetrofosmin uptake was compared to that of 201Tl in the setting of low flow and systolic dysfunction. METHODS: In nine open-chested dogs, a severe left anterior descending (LAD) coronary artery stenosis resulted in a 54.3% mean flow reduction and decreased left ventricular thickening from 21% +/- 1% to -3 +/- 2%. After 30 min, 37 MBq (1 mCi) of 201Tl and microspheres were injected and initial and 2-hr redistribution images acquired. Two hours later, 370 MBq (10 mCi) of 99mTc-tetrofosmin and microspheres were injected and an image was obtained. LAD: left circumflex (LCX) count ratios for both tracers and flows were calculated by well counting postmortem, and 201Tl and 99mTc-tetrofosmin defect magnitudes were determined by quantitative image analysis. RESULTS: LAD:LCx flow ratios were similar during 201Tl and 99mTc-tetrofosmin injections (0.48 +/- 0.04 versus 0.49 +/- 0.05, p = n.s.). Final 201Tl activity (0.66 +/- 0.04) was significantly higher than 99mTc-tetrofosmin (0.55 +/- 0.05; p < 0.05). LAD/LCx 99mTc-tetrofosmin image defect count ratio was similar to 201Tl defect count ratio on the initial rest 201Tl scan (0.57 +/- 0.03 versus 0.56 +/- 0.02, p = ns), but significantly less than 201Tl defect count ratio at 2 hr (0.57 +/- 0.03 versus 0.65 +/- 0.02, p < 0.05). CONCLUSION: In a low-flow model with profound systolic dysfunction, myocardial 99mTc-tetrofosmin uptake ( > 50%) reflective of viability was observed in the asynergic zone perfused by the stenotic LAD.     

Morphometric analysis of CD4+, CD8+, and gamma/delta+ T-lymphocytes in lymph nodes of cattle vaccinated with Brucella abortus strains RB51 and 19

We have often experienced false positive results of the stress Thallium-201 myocardial scintigraphy (TL) for the evaluation of artery bypass graft patency after coronary artery bypass surgery (CABG). The purpose of this study is to clarify the frequency and the clinical significance of this findings. Sixty-two patients undergoing coronary angiography (CAG) after CABG were studied. These patients had undergone at total of 156 bypasses (artery grafts 108, saphenous vein grafts 48, mean bypass grafts number 2.65/cases), and the mean period from CABG to TL was 41.6 +/- 34 days. The territories of stress induced ischemia were divided into 3 territories; left anterior descending (LAD), right coronary artery (RCA), and left circumflex (LCX) territories. Patency of the bypass grafts was estimated on the absence of transient perfusion defect (TPD) on TL images. The incidence of false positive results was higher in Dipyridamole TL (38%) than in Exercise TL (18%) and higher in LAD territories (38%) than in RCA (11%) and LCX (13%) territories. All false positive cases showed no evidence of chest pain and significant ST-T change during stress TL test. High incidence of false positive results of stress TL test was observed for the evaluation of artery bypass graft patency after CABG.     

Normal coronary flow reserve in patients with mitral valve prolapse, a positive exercise test and normal coronary arteries

We studied 12 patients (eight females and four males), ages 30-46 years, with echocardiographically documented mitral valve prolapse and clinical suspicion of coronary artery disease, based on a history of chest pain (five patients), angina-like pain (three patients), a positive exercise stress electrocardiogram (12 patients) and a focally positive thallium-201 stress perfusion scan (three patients), who were referred for cardiac catheterization and found to have normal coronary arteries. Ten patients without evidence of heart disease served as controls. In all mitral valve prolapse patients, coronary flow velocity reserve was determined successively in the left anterior descending, left circumflex and right coronary arteries as the ratio of the maximum (after intracoronary papaverine) to the resting mean coronary flow velocity. Coronary flow reserve values were fairly similar in the mitral valve prolapse and control patients; all 12 mitral valve prolapse patients had normal coronary flow reserve ( > or = 3.5) in all three coronary arteries with no significant differences among the arteries tested. Mean values +/- 1 standard deviation of the coronary flow reserve (mitral valve prolapse vs control patients) were 4.7 +/- 0.5 vs 4.6 +/- 0.6 for the left anterior descending, 4.6 +/- 0.4 vs 4.6 +/- 0.3 for the left circumflex and 4.5 +/- 0.4 vs 4.4 +/- 0.5 for the right coronary artery (all P = non-significant). The subsets of mitral valve prolapse patients with different clinical "ischaemic' manifestations were similar in terms of the calculated coronary flow reserve in all three major epicardial coronary arteries. In conclusion, this study demonstrated that an inadequate regional coronary flow reserve does not account for the clinical manifestations of myocardial ischaemia and positive exercise tests in patients with mitral valve prolapse and normal coronary arteries.     

Safety of dobutamine stress for thallium-201 myocardial perfusion tomography in patients with asthma

Many patients undergoing investigation for coronary artery disease are unable to exercise adequately due to physical or psychological reasons. Thallium-201 imaging using dipyridamole or adenosine may then be a suitable method of assessing myocardial perfusion. In patients with asthma, these drugs are contraindicated because of the risk of provoking bronchospasm. This study assesses the safety of dobutamine for thallium-201 myocardial perfusion imaging in patients with asthma who were unable to perform adequate exercise. Dobutamine was infused at rates < or = 40 micrograms/kg/min in 30 asthmatic patients for thallium-201 emission tomography. The severity of the airway reactivity ranged from mild to severe (bronchodilator treatment ranging from inhaled beta 2 agonists alone to maximal therapy including oral steroids). Coronary angiography was performed in 20 patients. Minor side effects of dobutamine were frequent, but did not limit the infusion rate. There were no episodes of bronchospasm, but tolerable dyspnea occurred in 8 patients who had reversible ischemia; this rapidly resolved with termination of the infusion. There were no serious cardiac complications, but chest pain occurred in 67% of patients. Thallium-201 images were abnormal in 10 of 11 patients with coronary artery disease (sensitivity 91%) and normal in 7 of 9 with normal coronary arteries (specificity 79%). Dobutamine thallium-201 myocardial perfusion tomography is a safe procedure in patients with asthma.     

Recent developments in the prognostic use of myocardial perfusion imaging

Stress myocardial perfusion imaging has become a mainstay in the noninvasive assessment of patients with known or suspected coronary artery disease for several compelling reasons. Radionuclide myocardial perfusion imaging can be performed using a variety of stressors, including exercise, pharmacologic stress (including dipyridamole, adenosine, dobutamine, and arbutamine), or a combination of exercise and pharmacologic stress. The combination of exercise and pharmacologic stress allows an assessment of the patient's exercise tolerance, to be performed while adequately stressing him or her pharmacologically. Radiopharmaceutical choice has been expanded to include not only thallium-201 but also technetium-based imaging agents such as sestamibi and tetrofosmin. The use of technetium imaging agents has recently been enhanced by the ability to assess ventricular function using gated single-photon emission computed tomography (SPECT) imaging techniques. Finally, the ability to provide prognostic information in the same patients has led to incremental clinical use.     

Comparison of coronary endothelial dynamics with electrocardiographic and left ventricular contractile responses to stress in the absence of coronary artery disease

Coronary artery endothelial dysfunction has been proposed as a cause of myocardial ischemia and symptoms in patients with angina-like chest pain despite normal coronary angiograms, especially those with ischemic-appearing ST-segment depression during exercise (syndrome X). We measured coronary vasomotor responses to acetylcholine (3 to 300 microg/min) in 42 patients (27 women and 15 men) with effort chest pain and normal coronary angiograms who also had normal electrocardiograms and echocardiograms at rest. All patients underwent treadmill exercise testing and measurement of systolic wall thickening responses to dobutamine (40 microg/kg/min) during transesophageal echocardiography. There were no differences in the acetylcholine-stimulated epicardial coronary diameter (+5+/-13% vs +1+/-13%, p=0.386) and flow (+179+/-90% vs +169+/-96%, p=0.756), or in the systolic wall thickening responses (+134+/-65% vs +118+/-57%, p=0.445) from baseline values in the 12 syndrome X patients compared with the 30 patients with negative exercise test results. In patients in the lowest quartile of coronary flow responses to acetylcholine, dobutamine increased systolic wall thickening by 121+/-73%; 3 had ischemic-appearing ST-segment depression during this stress. This contractile response to dobutamine was no different than the increase in systolic wall thickening (129+/-48%, p=0.777) in patients in the highest quartile of coronary flow responses, 3 of whom also had ischemic-appearing ST-segment depression during this stress. Thus, coronary endothelial dysfunction in the absence of coronary artery disease does not account for ischemic-appearing ST-segment depression in patients with chest pain despite normal coronary angiograms. Further, coronary endothelial dysfunction is not associated with myocardial contractile responses to stress consistent with myocardial ischemia.     

Somatostatin receptor subtypes sst1, sst2, sst3 and sst5 expression in human pituitary, gastroentero-pancreatic and mammary tumors: comparison of mRNA analysis with receptor autoradiography

The aim of this study was to elucidate further the causative mechanism of abnormal coronary vasomotion in patients with syndrome X. In patients with syndrome X, defined as angina pectoris and documented myocardial ischaemia during stress testing with normal findings at coronary angiography, abnormal coronary vasomotion of either the micro- or the macrocirculation has been suggested as the causative mechanism. Accordingly, we evaluated endothelial function, vasodilator reserve, and perfusion heterogeneity in these patients. Twenty-five patients with syndrome X (definitely normal coronary arteriogram, group A), 15 patients with minimal coronary artery disease (group B) and 21 healthy volunteers underwent [13N]ammonia positron emission tomography at rest, during cold pressor stimulation (endothelial function) and during dipyridamole stress testing (vasodilator reserve). Heterogeneity of myocardial perfusion was analysed by parametric polar mapping using a 480-segment model. In both patient groups, resting perfusion was increased compared to the normal subjects: group A, 127+/-31 ml.min-1.100 g-1; group B, 124+/-30 ml.min-1.100 g-1 normal subjects, 105+/-21 ml.min-1.100 g-1 (groups A and B vs normals, P<0.05). These differences were abolished after correction for rate-pressure product. During cold pressor stimulation, the perfusion responses (ratio of cold pressor perfusion to resting perfusion) were similar among the patients and the control subjects (group A, 1.20+/-0.23; group B, 1.24+/-0.22; normal subjects, 1.23+/-0.14). Likewise, during dipyridamole stress testing, perfusion responses were similar among the three groups (group A, 2.71+/-0.67; group B, 2.77+/-1.29; normal subjects, 2. 91+/-1.04). In group A the heterogeneity of resting perfusion, expressed as coefficient of variation, was significantly different from the volunteers (20.1+/-4.5 vs 17.0+/-3.0, P<0.05). In group B (coefficient of variation 19.4+/-3.9) the difference from normal volunteers was not significant. In this study, patients with syndrome X and patients with minimal coronary artery disease showed normal perfusion responses during cold pressor stimulation and dipyridamole stress testing. Our findings therefore suggest that endothelial dysfunction and impaired vasodilator reserve are of no major pathophysiological relevance in patients with syndrome X. Rather, other mechanisms such as increased sympathetic tone and focal release of vasoactive substances may play a role in the pathogenesis of syndrome X.     

Improved specificity of transesophageal dobutamine stress echocardiography compared to standard tests for evaluation of coronary artery disease in women presenting with chest pain

The detection of coronary artery disease (CAD) by noninvasive methods has been hindered in women by the high rate of false-positive results. To determine the feasibility and accuracy of transesophageal dobutamine stress echocardiography for identification of CAD in women, we studied 84 patients (age 51 +/- 11 years) who underwent symptom-limited exercise treadmill testing, exercise thallium-201 scintigraphy, and coronary angiography for evaluation of anginal chest pain. Of the 84 patients, 62 had normal coronary arteries or nonsignificant coronary lesions, and 22 had significant stenosis of > or = 1 major coronary artery. During treadmill exercise, repolarization changes were observed in 16 of 21 patients with CAD and in 19 of 60 patients with normal coronary arteries. With thallium scintigraphy, a reversible defect was observed in 19 of 22 patients with CAD and in 12 of 60 patients with normal coronary arteries. Regional wall motion abnormalities during dobutamine infusion developed in 18 of 22 patients with CAD and in none of the 62 patients with normal coronary arteries. All 3 tests had similar sensitivity for detection of CAD (76% for exercise treadmill test, 86% for thallium scintigraphy, and 82% for transesophageal dobutamine stress echocardiography). However, transesophageal dobutamine stress echocardiography had significantly higher specificity than the other 2 tests (100% vs 68% for exercise treadmill test and 80% for thallium scintigraphy; p = 0.0001). Thus, transesophageal dobutamine stress echocardiography is accurate for evaluation of CAD among women presenting with chest pain; its use should be considered when more conventional tests are equivocal or technically suboptimal.     

Involvement of spinal NMDA receptors in capsaicin-induced nociception

On poststress images with 99mTc-sestamibi (MIBI), increased lung uptake of the radiotracer may reflect severe or multivessel coronary artery disease. METHODS: We measured pulmonary/myocardial ratios of MIBI at standardized times on immediate poststress acquisitions and on delayed tomographic acquisitions. In 1500 sequential patients referred for rest and stress myocardial tomography, ancillary planar images were obtained 4 min postinjection at peak stress with exercise, either alone (exercise, n = 674), or after intravenous dipyridamole (dipyridamole, n = 826). RESULTS: Based on 95% confidence limits in the angiographic normals, high values for immediate acquisitions were found in 17% of dipyridamole studies and 15% of exercise studies. High values for delayed acquisitions were found in 10% of dipyridamole studies and 9% of exercise studies. For both stress modes, increased values were related (p < 0.001) to ischemic perfusion defects for immediate images, to fixed defects for delayed images, and to ventricular dilation in both cases. By logistic regression analysis, body weight and history of infarction were also minor independent determinants (p < 0.01) of delayed acquisitions. In a subset of 250 cases with angiographic correlation (163 with dipyridamole; 87 with exercise), immediate lung uptake was highly correlated with ventricular dysfunction and with coronary stenoses (p < 0.0001). Relationships were similar to those in a historic control series imaged with 201TI. Values for delayed poststress images, and for corresponding rest images, showed strong relationships to ventricular dysfunction but not to stenosis severity. CONCLUSION: The relationships of immediate lung uptake to scintigraphic and angiographic disease patterns suggest its possible diagnostic use as an indicator of stress-induced ventricular decompensation.     

Effect of gallopamil on myocardial microperfusion in patients with stable effort angina: a randomized, cross-over, double-blind, placebo-controlled trial

We evaluated the efficacy and safety of daily administration of gallopamil 150 mg/day and its effects on myocardial perfusion in a medium-term, randomized, double-blind, cross-over, placebo-controlled trial. We studied 19 patients (17 males and 2 females; mean age 57 +/- 6.8 years) with stable effort angina, angiographically documented coronary artery disease and reversible perfusion defects during exercise thallium-201 myocardial scintigraphy of at least one segment of the left ventricle. After 2 weeks of a single-blind placebo run-in period, during which each patient underwent at least 2 exercise tests and a 48-hour Holter ECG recording, all patients were treated with either placebo or gallopamil 50 mg t.i.d. for 28 days. At the end of this period, patients crossed over to the alternate regimen. This phase was double blind. After treatment with placebo or gallopamil, patients underwent exercise tests, 24-hour Holter ECG recording and thallium-201 myocardial scintigraphy. Weekly angina frequency and trinitroglycerin (TNT) consumption and safety were also evaluated. No patients dropped out of the study because of major side effects. The number of total ischemic and symptomatic events recorded at 24-hour ECG monitoring, weekly angina frequency and TNT consumption were significantly reduced during gallopamil treatment. After gallopamil administration, exercise duration significantly increased (run-in: 419 +/- 116 s, placebo: 420 +/- 118 s, gallopamil: 511 +/- 144 s; p < 0.05), and ST segment depression was significantly reduced (run-in: -1.3 +/- 0.3 mm, placebo: -1.3 +/- 0.3 mm, gallopamil: -0.94 +/- 0.68 mm; p < 0.01), while heart rate, systolic blood pressure and rate-pressure product were unchanged at rest, at submaximal and at peak exercise. Qualitative and quantitative evaluation of myocardial perfusion and the myocardial uptake percentage of thallium-201 in ischemic zones were significantly improved by gallopamil treatment. These findings demonstrate that gallopamil can improve myocardial perfusion and reduce myocardial oxygen consumption.     

Do parental convict cichlids of different sizes value the same brood number equally?

OBJECTIVES: We sought to determine endothelium-dependent vasodilator function in the brachial artery of patients with microvascular angina pectoris. BACKGROUND: Previous studies suggest the presence of endothelial dysfunction of the coronary microcirculation in patients with microvascular angina pectoris. It is not known whether endothelial dysfunction in these patients is a generalized process or whether it is confined to the coronary microcirculation only. METHODS: In 11 women (mean [+/-SD] age 60.1 +/- 7.8 years) with microvascular angina (anginal pain, normal epicardial coronary arteries, positive exercise stress test), endothelium-dependent vasodilation was assessed in the brachial artery by measuring the change in brachial artery diameter in response to hyperemic flow. Results were compared with 11 age- and gender-matched patients with known three-vessel coronary artery disease and 11 age- and gender-matched healthy control subjects. In all subjects, the intima-media thickness (IMT) of the common carotid artery was also measured. RESULTS: Flow-mediated dilation (FMD) was comparable in patients with microvascular angina and coronary artery disease (1.9 +/- 2.5% vs. 3.3 +/- 3.3%, p = NS) but was significantly lower in patients with microvascular angina than in healthy control subjects (1.9 +/- 2.5% vs. 7.9 +/- 3%, p < 0.05). IMT was significantly lower in patients with microvascular angina than in those with coronary artery disease (0.64 +/- 0.08 vs. 1.0 +/- 0.28 mm, p < 0.05) and was comparable between patients with microvascular angina pectoris and healthy control subjects (0.64 +/- 0.08 vs. 0.56 +/- 0.14 mm, p = NS). IMT > or = 0.8 mm was observed in 1 of 11 patients with microvascular angina, 1 of 11 control subjects and 10 of 11 patients with coronary artery disease. CONCLUSIONS: These findings suggest that endothelial dysfunction in microvascular angina is a generalized process that also involves the peripheral conduit arteries and is similar to that observed in atherosclerotic disease. IMT could be helpful in discriminating patients with microvascular angina and atherosclerotic coronary artery disease.     

Improvement of exercise capacity by sarpogrelate as a result of augmented collateral circulation in patients with effort angina

OBJECTIVES: The purpose of this study was to evaluate whether a serotonin blocker, sarpogrelate, improves exercise capacity as a result of vasodilation of coronary collateral channels in patients with effort angina. BACKGROUND: Serotonin has been reported to decrease coronary collateral blood flow by collateral vasoconstriction in a canine model, suggesting that platelet activation in feeding coronary arteries of the collateral network has the potential to cause collateral vasoconstriction. METHODS: The subjects consisted of 22 patients with effort angina and reproducible ischemic threshold (group A, 11 patients with thrombolysis in myocardial infarction (TIMI) grade 2 or 3 flow of the ischemia-related coronary artery and Rentrop's collateral index 0 or 1; group B, 11 patients with TIMI grade 0 or 1 flow and Rentrop's collateral index 2 or 3). We repeated the symptom-limited treadmill exercise test using the Balke-Ware protocol and exercise tetrofosmin myocardial perfusion scintigraphy with and without pretreatment with 200 mg orally administered sarpogrelate. Each exercise test was performed at 9:00 a.m. on different days. The order of tests with and without sarpogrelate was randomized. RESULTS: In group A, sarpogrelate increased neither exercise time at 0.1 mV ST depression nor double product at 0.1 mV ST depression. In contrast, in group B sarpogrelate increased the exercise duration at 0.1 mV ST depression from 181+/-112 (SD) to 248+/-131 s (p < 0.05) and also increased the double product at 0.1 mV ST depression by 21% (p < 0.01). The severity score using myocardial perfusion scintigraphy at the same workload was significantly (p < 0.01) decreased by 37% in group B, but not in group A (11%), due to the sarpogrelate treatment. CONCLUSIONS: Sarpogrelate augments flow reserve of the collateral circulation and improves exercise capacity in anginal patients with well-developed collaterals. These findings indicate that a serotonin blocker, sarpogrelate, is useful not only as an antiplatelet drugs, but as an antianginal drug.     

A noninjury, diet-induced swine model of atherosclerosis for cardiovascular-interventional research

To investigate whether atherosclerotic vascular disease in the microswine model can be induced by atherogenic diet alone and does not require balloon injury or endothelial denudation as widely stated in the literature, 28 female Yucatan microswine were fed a high-fat, high-cholesterol diet, including 2% sodium cholate, for an average of 310 +/- 13 days. Four control swine were placed on a regular diet for an average of 287.2 +/- 7.8 days. Selective coronary arteriography and morphologic and histologic studies were performed at the end of this period. Coronary arteries were fixed in vivo by pressure perfusion of formalin. Angiograms and sequential histologic sections were reviewed by a double-blind team. The angiography did not show apparent disease in all vessels but generally revealed mild irregularity. Quantitatively, there was a 30.5 +/- 3.5% stenosis (mean +/- standard error, P < 0.05 vs. control) in left anterior descending (LAD), 40.7 +/- 4.5% of stenosis in right coronary artery (RCA) (P < 0.01 vs. control), and 24.8 +/- 3.7% of stenosis in left circumflex artery (LCX). The lesions were eccentric in 95% of LCA, 95.8% of RCA, and 75% of LCX, and the remainder were concentric lesions. Typical lesions were characterized by significant intimal proliferation, cholesterol clefts, necrotic cores, heavy extracellular fat deposition, and calcification. Control animals had only occasional, minimal intimal lipid deposition in coronary arteries. These findings suggest that the Yucatan microswine is an ideal coronary atherosclerosis animal model for vascular research. Lesions can be induced by atherogenic diet alone. Cholesterol uptake is increased by adding sodium cholate to the feed. Moreover, balloon injury of the intima or media is not required to induce significant atherosclerotic lesions in coronary arteries.