Dental fear with and without blood-injection fear: implications for dental health and clinical practice

BACKGROUND: It has been suggested that the sympathetic nervous system might play an important role in the development of coronary artery spasm. However, no cardiac imaging modality has been able to demonstrate abnormal sympathetic innervation in patients with coronary artery spasm. The purpose of this study was to assess the presence and location of abnormal sympathetic innervation using iodine 123-metaiodobenzylguanidine (123I-MIBG) single photon emission computed tomography (SPECT) and to evaluate the clinical efficacy of 123I-MIBG SPECT as a noninvasive screening test in patients with coronary artery spasm. METHODS AND RESULTS: Coronary arteriography and a provocative test with intravenous administration of ergonovine maleate were performed in 26 patients (20 men, 6 women, mean age 48.2+/-12.0 years, range 20 to 67 years) who were suspected of having a coronary artery spasm. The subjects were divided into 2 groups: group 1 (n = 18) comprised subjects with a positive provocative test result, and group 2 (n = 8) comprised subjects with negative provocative test results. Ten healthy subjects served as controls. No abnormal MIBG uptake was observed in the control subjects. Abnormal sympathetic nervous innervation using 123I-MIBG SPECT was observed either as a reduced uptake or a defective pattern in the perfused areas in 13 of the 18 regions supplied by vessels of ergonovine-induced vasospasm. Normal sympathetic innervation, as evidenced by normal 123I-MIBG uptake, was noted in all of the 60 segments of normal vessel territories. Reduced uptake of 123I-MIBG was not detected in the perfused areas of 5 vasospasm-induced vessels (perfusion territory of left anterior descending coronary artery [LAD] and the right coronary artery [RCA] in 2 and 3 patients, respectively). The sensitivity and specificity of 123I-MIBG for detection of coronary artery spasm were 72.2% (95% confidence interval [CI] 55% to 89%) and 100%, respectively. The positive predictive and negative predictive values were 100% and 92.3% (95% CI 91% to 93%), respectively. CONCLUSION: 123I-MIBG SPECT is a feasible method to evaluate noninvasively and localize the territories of coronary arteries with spasm. Invasive diagnostic coronary arteriography with ergonovine provocation test may be unnecessary for diagnosis of coronary artery spasm in patients with typical resting pain, negative exercise test or normal thallium perfusion scan results, but showing abnormalities in 123I-MIBG SPECT.     

99Tcm-sestamibi tomoscintigraphy at rest and after nitrate administration in predicting wall motion recovery after revascularization

To evaluate whether nitroglycerin administered before the injection of sestamibi improves the detection of viable but hypoperfused myocardium, 41 post-infarction patients with left ventricular dysfunction underwent echocardiography and SPET at rest and after nitrate administration. In 25 revascularized patients, perfusion at rest and contractility were assessed 3-4 months after coronary artery bypass grafting. Perfusion (PI) and wall motion indices (WMI) were calculated for each revascularized area. There was a strong correlation between contractility and perfusion defect (r = 0.58, P < 0.0001). Nitrates significantly reduced the number of perfusion defects in hypokinetic (delta PI = 0.25 +/- 0.66) and akinetic (delta PI = 0.32 +/- 0.62), but not in dyskinetic (delta PI = 0.08 +/- 0.62), segments. Twenty-five revascularized patients had 110 asynergic segments and 136 segments with a resting perfusion defect. Function improved in 42% and perfusion in 64% of segments after surgery. Viable segments had a lower PI at rest (2.78 +/- 1.38 vs 3.86 +/- 1.29, P < 0.001) and a lower WMI (2.46 +/- 0.50 vs 2.79 +/- 0.59, P = 0.002). Nitrates reduced the number of perfusion defects slightly more in viable than non-viable segments (delta PI = 0.58 +/- 0.89 vs 0.30 +/- 0.46, P = 0.06). Contractility and perfusion at rest were the most important predictors of functional recovery. The sensitivity and specificity in predicting contractile improvement were 74% and 64% for resting SPET respectively, and 80% and 50% for nitrate SPET respectively. Nitrate administration significantly reduces perfusion defects in asynergic regions; however, its usefulness in predicting contractile recovery may be limited owing to its low specificity. Contractility and sestamibi uptake at rest were the strongest predictors of post-operative wall motion improvement.     

Heterogeneous sympathetic innervation in German shepherd dogs with inherited ventricular arrhythmia and sudden cardiac death

BACKGROUND: Recently, a colony of German shepherd dogs with inherited spontaneous cardiac arrhythmias and associated sudden death has been developed and characterized. Due to the median age of onset of the arrhythmia (4.5 months), the tendency for the arrhythmia to occur during REM sleep or after exercise, and the absence of structural heart disease, we hypothesized a developmental abnormality of the sympathetic innervation to the heart. METHODS AND RESULTS: We studied 11 dogs from this colony, ranging in age from 6 months to 6 years, and four 7-month-old German shepherd dogs unrelated to the colony as controls. We imaged the distribution of functional myocardial sympathetic innervation and perfusion with [123I]metaiodobenzylguanidine (MIBG) and 201Tl, respectively. Sympathetic nerve distribution was evaluated morphologically by immunocytochemical localization of tyrosine hydroxylase. All of the hearts showed evidence of a regional decrease in MIBG uptake, ranging from 5.3% to 53.4% of the myocardium, whereas control dogs showed homogeneous MIBG uptake. Immunocytochemical studies on sections from regions with decreased MIBG uptake showed a striking paucity of nerves compared with regions with normal MIBG uptake, confirming denervation. When the dogs were grouped into those with (n=6) and without (n=5) evidence of ventricular tachycardia on ambulatory ECG, the group with ventricular tachycardia showed 35+/-16.5% denervation, whereas the group without ventricular tachycardia showed 12+/-5.6% denervation (P<.02). CONCLUSIONS: Abnormal heterogeneous sympathetic innervation exists in these dogs with inherited ventricular arrhythmia and sudden cardiac death. Mechanisms relating the presence and extent of regional denervation to the incidence of ventricular arrhythmia remain to be defined.     

Coronary collateral circulation behaviour and myocardial viability in chronic total occlusion treated with coronary angioplasty

AIMS: We explored the role of microcirculation integrity following the chronic occlusion of an infarct-related artery to assess the behaviour of collateral circulation during and after reperfusion by coronary angioplasty METHODS AND RESULTS: Eighteen patients with a proximally occluded left anterior descending artery and firm evidence of intercoronary collateral circulation were studied with selective coronary angiography and selective intracoronary myocardial contrast echocardiography, before coronary angioplasty, and at 5 and 15 min and 12 h later. Myocardial enhancement during myocardial contrast echocardiography was evaluated with a semiquantitative score (0-3), which was correlated to basal and 6 months' regional left ventricular wall motion results. 16/18 procedures were successfully performed; four patients with an inadequate acoustic window were excluded. Restenosis was evident at the 6 months' follow-up in two patients. Basal myocardial contrast echocardiography indicated that 81/192 segments from the left anterior descending coronary artery and 90/192 from the right coronary artery were perfused; no perfusion was observed in 21 segments either before or after coronary angioplasty. After coronary angioplasty, the angiographic intercoronary collateral circulation immediately disappeared, and myocardial contrast echocardiography revealed that there was a progressive reduction of segments perfused by the right coronary artery and an increase in segments perfused by the left anterior descending coronary artery. Regional left ventricular wall motion analysis demonstrated that there was abnormal motion in 51/192 segments. There was no improvement in segments with score 0 and abnormal motion after 6 months (100% sensitivity), but 16/17 segments with score 3 did show an improvement (98% specificity). The predictive value of intermediate scores (1-2) in detecting long-term improvement, was only 43%. CONCLUSION: These data show that the adaptive mechanism observed in the behaviour of epicardial and microvascular circulation after reperfusion of a chronic occluded infarct-related artery can vary. In addition, this study clearly shows that microvascular integrity detected by myocardial contrast echocardiography can provide myocardial viability.     

Impairment of regional fatty acid uptake in relation to wall motion and thallium-201 uptake in ischaemic but viable myocardium: assessment with iodine-123-labelled beta-methyl-branched fatty acid

In coronary artery disease, discrepancy in the uptake of thallium-201 and of methyl-branched fatty acid at rest has been described. The purpose of this study was to evaluate iodine-123 labelled beta-methyl-branched fatty acid (BMIPP) myocardial uptake and wall motion at rest in segments with stress-induced ischaemia identified by stress 201Tl tomography in patients with chronic coronary artery disease. 123I-BMIPP myocardial tomography was performed at rest and was compared with the findings of exercise-reinjection 201Tl tomography in 45 patients with chronic coronary artery disease. Regional wall motion was evaluated by contrast left ventriculography in 36 patients. Among 237 segments with reversible 201Tl defects, equally decreased uptake on both reinjection 201Tl and BMIPP images was observed in 93 (39%), more severely decreased uptake of BMIPP in 118 (50%) and more severely decreased uptake of reinjection 201Tl in 26 (11%). On the other hand, among 90 segments with non-reversible 201Tl defects, each pattern was observed in 71 (79%), 6 (7%) and 13 (14%) segments, respectively. When comparing the ischaemic segments with and without more severely reduced uptake of BMIPP than of reinjection 201Tl, wall motion was impaired to a greater extent in the segments with more severely reduced uptake of BMIPP than of reinjection 201Tl [severe hypo- or dyskinesis was present in 64 (70%) of 91 segments and in 24 (22%) of 110 segments, respectively, P<0.005]. In patients with chronic coronary artery disease, resting fatty acid uptake was frequently more reduced than reinjection 201Tl in the segments with stress-induced ischaemia, while in most of the fixed perfusion defects BMIPP and reinjection 201Tl uptake decreased concordantly. In ischaemic myocardium, wall motion was impaired to a greater extent in those segments which showed more severely reduced uptake of BMIPP than of reinjection 201Tl. In ischaemic but viable myocardium, discordant BMIPP uptake less than reinjection 201Tl uptake may indicate metabolic alterations and wall motion abnormality at rest independent of perfusion abnormalities. In conclusion, the combination of resting BMIPP and stress-reinjection 201Tl imaging may provide information on metabolic alterations and wall motion abnormality at rest independent of perfusion abnormalities.     

Managed care and outcomes of hospitalization among elderly patients with congestive heart failure

123I-radiolabeled metaiodobenzylguanidine (123I-MIBG) cardiac imaging has been used to evaluate the distribution of sympathetic nervous system (SNS) in the heart. Different heart diseases have shown impaired cardiac SNS distribution as reflected by MIBG activity. The aim of this study was to assess the cardiac distribution of SNS in normal subjects, using MIBG imaging. Ten normal subjects (1 male and 9 females, mean age 46 +/- 9 years) with no cardiac abnormalities underwent myocardial 123I-MIBG scintigraphy, Tc-99m methoxyisobutylisonitrile (MIBI) cardiac perfusion imaging and equilibrium radionuclide angiography (RNA). Regional myocardial MIBG and MIBI activities were quantitatively evaluated using a region of interest analysis. For this purpose, the left ventricle was divided into 6 myocardial regions as anterior, apical, inferior, septum, lateral and posterolateral. In particular, myocardial MIBG and MIBI activities were measured as myocardium to mediastinum ratio. Regional left ventricular function was assessed by RNA. Myocardial MIBG uptake was homogeneous in anterior (2.2 +/- 0.5), inferior (2.5 +/- 0.7), septal (2.4 +/- 0.4), lateral (2.3 +/- 0.4), and posterolateral (2.3 +/- 0.4) regions. Conversely, MIBG uptake was significantly lower in the apical region (1.9 +/- 0.3) compared to all other left ventricular segments (p < 0.05). Regional myocardial perfusion, as measured by MIBI uptake, was homogeneous in all regions. No regional left ventricular wall motion abnormalities were observed by RNA. In conclusion, our data suggest that a decreased MIBG uptake may be observed in the left ventricular apical region of normal subjects reflecting reduced sympathetic innervation of the apex. This finding is not related to myocardial perfusion or wall motion abnormalities. The knowledge of cardiac sympathetic innervation in normal subjects may be helpful to assess SNS abnormalities in heart disease.     

New directions in myocardial perfusion imaging

In recent years, substantial progress has been made in the field of nuclear cardiology. Pharmacologic stress perfusion imaging with intravenous administration of dipyridamole or adenosine provides comparable sensitivity and specificity values for detection of coronary artery disease (CAD) as exercise imaging and has been employed successfully for risk stratification prior to peripheral vascular or aortic surgery and after myocardial infarction. Detection of myocardial viability can be enhanced utilizing reinjection of a second dose of thallium-201 (Tl-201) at rest after acquisition of redistribution images with the single photon emission computerized tomography (SPECT) technique. Imaging solely in the resting state with Tl-201 can also provide information concerning presence of viable myocardium in asynergic regions that are stunned or hibernating. New technetium-99m (Tc-99m) perfusion agents have emerged in the clinical setting and have provided excellent predictive value for detection of CAD in patients with chest pain and permit simultaneous assessment of function and regional blood flow. Tc-99m Sestamibi, one of these agents, is also a valid marker of viability when assessing myocardial salvage after coronary reperfusion in acute myocardial infarction.     

Detection of severity of coronary stenosis by quantitative myocardial tomography with Tc-99m-MIBI at rest

To evaluate the role of myocardial tomography with Tc-99m-MIBI (MB) in detecting abnormal coronary arteries, 34 patients with myocardial infarction underwent resting quantitative SPEC with MB and coronary arteriography within one month. When segmental MB uptake was < 560% of the left ventricular peak activity, there was 88% probability that a totally occluded or severely stenosed coronary artery (stenosis > 90%) was involved. There was 82% probability of finding no significant stenosis of coronary arteries in the normal myocardial segments. In the myocardial segments supplied by occluded coronary arteries, there was significantly higher MB uptake in the segments with good collateral circulation as compared with those subtended by a vessel totally occluded with poor collateral circulation (P < 0.05). The sensitivity and specificity of detecting abnormal coronary artery by quantitative analysis of myocardial tomography was 87% and 90% respectively. It is suggested that quantitative analysis of myocardial tomography with MB can differentiate between myocardial segments supplied by severely stenosed and normal coronary artery and evaluate the existence of collateral circulation.     

Regional myocardial motion and thickening assessed at rest by ECG-gated 99mTc-MIBI emission tomography and by magnetic resonance imaging

We have validated ECG-gated emission tomography using technetium-99m methoxyisobutylisonitrile for the assessment of regional ventricular function by comparing it with cine magnetic resonance imaging (MRI). Gated tomography was performed at rest in 24 patients referred for myocardial perfusion imaging [17 males and seven females with a mean age of 58 years, nine of whom had had a previous myocardial infarction (MI)]. Scores were assigned to each of nine myocardial segments for wall motion and for thickening. Cine MRI was analysed in an identical fashion. Four out of 216 (2%) segments were uninterpretable by gated tomography because of inadequate tracer uptake. In eight patients without coronary artery disease (CAD), wall motion and thickening were normal by both methods. Gated tomography showed abnormal wall motion or thickening in all patients with previous MI and in five of seven patients with CAD but no prior MI. Association between wall motion and thickening was good (rs=0. 86). Overall, there was good agreement between gated tomography and MRI for both wall motion (178/212 segments, kappa=0.66) and wall thickening (184/212 segments, kappa=0.69). In segments with severely reduced perfusion, however, there was poorer agreement (kappa=0.31). Interobserver and intraobserver agreement was high (kappa from 0.61 to 0.78). Thus, in patients investigated for CAD, there is good overall agreement between gated tomography and MRI but the agreement is lower in segments with severe perfusion defects.     

Comparison of myocardial contrast echocardiography and low-dose dobutamine stress echocardiography in predicting recovery of left ventricular function after coronary revascularization in chronic ischemic heart disease

BACKGROUND: Dobutamine stress echocardiography (DSE) and myocardial contrast echocardiography (MCE) can predict recovery of left ventricular function after myocardial infarction. DSE also has been shown to predict left ventricular functional recovery after revascularization in chronic ischemic heart disease, whereas MCE has not been evaluated in such patients. This study was performed to compare DSE and MCE in the prediction of left ventricular functional recovery after revascularization in patients with chronic ischemic heart disease. METHODS AND RESULTS: MCE and DSE were performed in 35 patients with chronic coronary artery disease and significant wall motion abnormalities (mean ejection fraction, 0.36 +/- 0.09). Regional wall motion was scored by use of a 16-segment model wherein 1 = normal or hyperkinetic, 2 = hypokinetic, 3 = akinetic, and 4 = dyskinetic. Each segment was evaluated for contractile reserve by DSE and perfusion by MCE. Revascularization (coronary artery bypass graft [n = 13] and percutaneous transluminal coronary angioplasty [n = 10]) was successful in 23 patients. Follow-up echocardiograms were done to assess wall motion 30 to 60 days later. In 238 segments with resting wall motion abnormalities, perfusion was more likely to present than contractile reserve (97% versus 91%, P < .02). Revascularization resulted in functional recovery in 77 of 95 hypokinetic segments (81%) but only 18 of 57 akinetic segments (32%, P < .0001). DSE and MCE were not significantly different in predicting functional recovery of hypokinetic segments. In akinetic segments, DSE and MCE had similar sensitivities (89% versus 94%, respectively) and negative predictive values (93% and 97%, respectively) in predicting functional recovery. However, DSE had a higher specificity (92% versus 67%, P < .02) and positive predictive value (85% versus 55%, P < .02) than MCE in predicting functional recovery. CONCLUSIONS: Both contractile reserve by DSE and perfusion by MCE are predictive of functional recovery in hypokinetic segments after coronary revascularization in patients with chronic coronary revascularization in patients with chronic coronary artery disease. In akinetic segments, myocardial perfusion by MCE may exist in segments that do not recover contractile function after revascularization. Thus, contractile reserve during low-dose dobutamine infusion is a better predictor of functional recovery after revascularization in akinetic segments than perfusion.     

Children''s spiritual response: validation of the nursing diagnosis spiritual distress

A variety of new radiopharmaceutical agents have been introduced to probe myocardial function in vivo. This review will introduce these new techniques which have recently been available in Japan. Tc-99m perfusion imaging agents provide excellent myocardial perfusion images which may enhance diagnostic accuracy in the study of coronary artery disease. In addition, greater photon flux from the tracer permits simultaneous assessment of regional perfusion and function with use of first-pass angiography or ECG-gated acquisition. Positron emission tomography enables metabolic assessment in vivo. Preserved FDG uptake indicates ischemic but viable myocardium which is likely to improve regional dysfunction after revascularization. In addition, FDG-PET seems to be valuable for selecting a high risk subgroup. Recently I-123 BMIPP, a branched fatty acid analog, has been clinically available in Japan. Less uptake of BMIPP than thallium is often observed in the ischemic myocardium. Such perfusion metabolic mismatch which seems to be similarly observed in FDG-PET is identified in the stunned or hibernating myocardium with regional dysfunction. Both of them are likely to recover afterwards. Severe ischemia is identified as reduced BMIPP uptake at rest, suggesting its role as an ischemic memory imaging. I-123 MIBG uptake in the myocardium reflects adrenergic neuronal function in vivo. In the study of coronary artery disease, neuronal denervation is often observed around the infarcted myocardium and post ischemic region as well. More importantly, reduced MIBG uptake in these patients can identify high risk for ventricular arrhythmias and assess severity of congestive heart failure. These new techniques will provide insights into new pathological states in the ischemic heart disease and enable to select optimal treatment in these patients.     

Value of transthoracic two-dimensional echocardiography in predicting viability in patients with healed Q-wave anterior wall myocardial infarction

The role of transthoracic echocardiography as a predictor of recovery after revascularization has not yet been established. Two-dimensional echocardiography was performed in 15 patients with a healed anterior wall myocardial infarction and severe, isolated stenosis of the left anterior descending coronary artery before, and 3 to 6 months after angiographically confirmed successful revascularization. The asynergic segments were classified into 2 groups according to 2 different echocardiographic patterns: those showing a normal acoustic reflectance with normal end-diastolic thickness (pattern A segments) and those showing an increase in acoustic reflectance and reduced end-diastolic thickness (pattern B segments). We hypothesized that pattern A segments were more likely to recover (viable myocardium) and that pattern B segments were consistent with irreversibility. A total of 240 segments in the 15 patients were evaluated before and after revascularization. Sixty-seven segments were asynergic; of these, 52 were judged to have pattern A and 15 pattern B. Of the 52 pattern A segments, 27 were hypokinetic and 25 akinetic. All of the pattern B segments were akinetic (n = 9) or dyskinetic (n = 6). Pattern A was predictive of postoperative recovery in 39 of 52 segments (75%) (p < 0.0001); pattern B was predictive of irreversibly damaged tissue in 13 of 15 segments (87%) (p < 0.0001). Thus, in patients with healed anterior wall myocardial infarction, resting transthoracic echocardiography is a simple and reliable predictor of the behavior of asynergic segments after revascularization.     

A 23-year-old patient with neurofibromatosis associated with acute myocardial infarction, vasospasm and a coronary artery ectasis

We treated a 23-year-old male with neurofibromatosis with acute myocardial infarction. Cardiac catheterization revealed severe organic stenosis in the left anterior descending artery, an ectasic left circumflex artery and a small right coronary artery. Percutaneous transluminal coronary angioplasty (PTCA) was performed on the stenosis. In follow-up catheterizations, intracoronary administration of ergometrine induced vasospasm of the left coronary artery including at the PTCA site. An I 123 metaiodobenzylguanidine (MIBG) scintigram showed defects in the septum, inferior wall and apex. These findings suggest abnormality of the cardiac sympathetic nerve in neurofibromatosis.     

Myocardial contrast echocardiography versus dobutamine echocardiography for predicting functional recovery after acute myocardial infarction treated with primary coronary angioplasty

OBJECTIVES: We sought to compare myocardial contrast echocardiography with low dose dobutamine echocardiography for predicting 1-month recovery of ventricular function in acute myocardial infarction treated with primary coronary angioplasty. BACKGROUND: The relation between myocardial perfusion and contractile reserve in patients with acute myocardial infarction, in whom anterograde flow is fully restored without significant residual stenosis, is still unclear. METHODS: Thirty patients with acute myocardial infarction treated successfully with primary coronary angioplasty underwent intracoronary contrast echocardiography before and after angioplasty and dobutamine echocardiography 3 days after the index infarction. One month later, two-dimensional echocardiography and coronary angiography were repeated in all patients and contrast echocardiography in 18 patients. RESULTS: After coronary recanalization, 26 patients showed myocardial reperfusion within the risk area, although 4 did not. At 1-month follow-up, all patients had a patient infarct-related artery without significant restenosis. Both left ventricular ejection fraction and wall motion score index within the risk area significantly improved in the patients with reperfusion ([mean +/- SD] 38 +/- 8% vs. 48 +/- 12%, p < 0.005; and 2.35 +/- 0.5 vs. 2 +/- 0.6, p < 0.001, respectively), but not in those with no reflow. Of the 72 nonperfused segments before angioplasty, 27 showed functional improvement at follow-up. Myocardial contrast echocardiography had a sensitivity and a negative predictive value similar to dobutamine echocardiography in predicting late functional recovery (96% vs. 89% and 89% vs. 93%, respectively), but a lower specificity (18% vs. 91%, p < 0.001), positive predictive value (41% vs. 86%, p < 0.001) and overall accuracy (47% vs. 90%, p < 0.001). CONCLUSIONS: Microvascular integrity is a prerequisite for myocardial viability after acute myocardial infarction. However, contrast enhancement shortly after recanalization does not necessarily imply a late functional improvement. Thus, contractile reserve elicited by low dose dobutamine is a more accurate predictor of regional functional recovery after reperfused acute myocardial infarction than microvascular integrity.     

Iodine-123 metaiodobenzylguanidine cardiac imaging to identify and localize vasospastic angina without significant coronary artery narrowing

OBJECTIVES: We assessed the ability of iodine-123 metaiodobenzylguanidine (MIBG) imaging to identify and localize coronary spasm and determined the most useful method of MIBG analysis in vasospastic angina without significant coronary narrowing. BACKGROUND: Various noninvasive methods have been used to detect vasospastic angina, but they are not very sensitive in patients with sporadic attacks. MIBG imaging has recently been proposed as a useful tool for detecting vasospastic angina. METHODS: Normal limits of both visual and quantitative analysis of two-dimensional polar maps (bull's-eyes) for MIBG imaging were at first established in 59 normal subjects. For optimal criteria of visual analysis, we established regional differences in abnormal MIBG defect scores. An abnormal region of the bull's-eye was defined as an area > 2 SD below normal. An abnormal regional washout rate was defined as < 0%. Using these criteria, we prospectively evaluated 104 patients with suspected vasospastic angina. Visual, bull's-eye and regional washout rate analyses were compared for overall detection of the disease and for individual vessel involvement. RESULTS: Overall sensitivity by these methods was 30%, 42% and 76%, respectively. Washout rate analysis showed a significantly higher sensitivity than the other two methods. Specificity was 78%, 72% and 87%, respectively. The sensitivity of detecting spasm-induced coronary artery with washout rate analysis was 82% for the left anterior descending (LAD), 76% for the right (RCA) and 69% for the circumflex (Cx) coronary arteries. The sensitivity of visual analysis was 29%, 15% and 35%, respectively; that for bull's-eye analysis was 34%, 54% and 41%, respectively. Washout rate analysis showed a significantly higher sensitivity for LAD spasm than for the other two methods and a higher sensitivity for RCA and Cx spasms than for visual analysis. CONCLUSIONS: Regional washout rate analysis of MIBG imaging is a highly accurate technique for determining the presence and location of coronary artery spasm.     

Enhanced detection of proximal right coronary artery stenosis with the additional analysis of right ventricular thallium-201 uptake in stress scintigrams

The value of right ventricular thallium-201 analysis in detecting proximal right coronary artery stenosis in exercise myocardial scintigraphy was analyzed in 52 patients, 27 with and 25 without proximal right coronary artery stenosis. For the detection of proximal right coronary artery stenosis, the sensitivity and specificity of thallium scintigraphic analysis were 59 and 88% for a right ventricular abnormality, 67 and 68% for a left ventricular inferior wall abnormality, and 93 and 56% for an abnormality of either. When both right and left ventricular thallium images were abnormal, all 9 patients had proximal right coronary artery stenoses, and when both were normal, 26 of 28 patients had a normal proximal right coronary artery. The sensitivity and specificity of blood pool scintigraphic variables during exercise (right ventricular ejection fraction and left ventricular inferior wall motion) were not significantly different for detection of proximal right coronary artery stenosis. Thus, the additional analysis of the right ventricle on thallium-201 stress scintigrams can improve the detection of proximal right coronary artery stenosis. When both right ventricular and left ventricular thallium scintigrams are abnormal (or normal), the ability to predict the presence (or absence) of proximal right coronary artery stenosis is very high.     

Utility of stress single-photon emission computed tomography (SPECT) perfusion imaging in predicting outcome after coronary artery bypass grafting

Previous studies have examined the predictors of outcome in medically treated patients with coronary artery disease (CAD). There is limited information on predictors of outcome after coronary artery bypass grafting (CABG). This study examined the predictors of outcome of 255 patients with CAD, at a mean time of 5 years after CABG for angina pectoris. The 255 patients underwent coronary angiography and stress single-photon emission computed tomography (SPECT) myocardial perfusion imaging after CABG. During a mean follow-up of 41 +/- 28 months after stress testing, there were 34 hard events (24 cardiac deaths and 10 nonfatal myocardial infarctions). The hemodynamics during stress testing, and age and gender were not predictors of events. The SPECT variables of multivessel perfusion abnormality, perfusion deficit size, and increased lung thallium uptake were predictors of death and total events by uni- and multivariate survival analysis. There were 14 events in 45 patients (31%) with multivessel abnormality and increased lung thallium uptake, 14 events in 101 patients (14%) with either multivessel abnormality or increased lung uptake, and 6 events in 109 patients (6%) with neither of these 2 variables (p = 0.0001). The annual mortality and total event rates were 7.5% and 9.5% with both variables, 3.4% and 4.3% with either variable, and 0.6% and 1.7% with neither of the variables (p = 0.01). Thus, stress SPECT perfusion imaging is useful to stratify patients after CABG into low, intermediate, and high risk groups for future cardiac events.     

Comparison of persistent thallium perfusion defects by quantitative washout analysis with thallium reinjection in patients with coronary artery disease

Thallium reinjection can improve the detection of severely ischemic viable myocardium in patients with coronary artery disease. However, a disadvantage of this method is that it requires the acquisition of 3 separate sets of images and the administration of an additional dose of the radiotracer. Alternatively, quantitative analysis of the regional myocardial washout of thallium-201 can be easily obtained from the conventional postexercise and redistribution images without additional imaging time or radiation exposure to the patient. To determine whether this method can predict the results of thallium reinjection, this study analyzed thallium-201 images of 31 patients who had persistent perfusion defects in qualitative exercise/delayed redistribution single-photon emission computed tomographic thallium studies and who underwent thallium reinjection. The quantitative mean radioactive counts of each myocardial segment that had a persistent perfusion defect in the initial and delayed redistribution on 4-hour short-axis tomographic slices were measured to derive a delayed/initial ratio, and these values were compared with the results of thallium reinjection. The delayed/initial ratio was 1.06 +/- 0.22 in 39 segments that improved, versus 0.58 +/- 0.18 in 43 segments without improvement after reinjection (p < 0.001). Thirty-eight of the 39 segments that improved had a ratio of > or = 0.75, versus only 3 of the 43 segments that showed no improvement (sensitivity, 98%; specificity, 91%). The correlation between the delayed/initial ratio and reinjection results was equally high at any segment location or severity. It is concluded that quantitative regional thallium washout analysis predicts the results of thallium reinjection in segments with persistent thallium defects.(ABSTRACT TRUNCATED AT 250 WORDS)     

Accuracy of single-photon emission computed tomography myocardial perfusion imaging in patients with stents in native coronary arteries

Strategies to noninvasively evaluate patients after coronary stenting have not been evaluated. To determine the accuracy of single-photon emission computed tomography (SPECT) myocardial perfusion imaging in patients after coronary stenting, 209 patients who had undergone stenting followed by late stress SPECT myocardial perfusion imaging were evaluated. Quantitative coronary angiography was performed in 33 patients following SPECT imaging. SPECT restenosis was defined as a reversible or fixed defect within the stented vascular territory. Angiographic restenosis was examined using 2 definitions: total area narrowing > or =50% or > or =70% of the stent site or stented artery. The SPECT and angiographic findings were concordant in 22 of 33 stented vascular territories using the 50% definition of restenosis and in 29 of 33 stented territories using the 70% definition. Use of the 70% definition of restenosis resulted in improved accuracy of SPECT to detect a significant stenosis in the stented artery. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of SPECT were 95%, 73%, 88%, 89%, and 88% respectively. In patients with positive SPECT scans, the most significant stenosis in the stented artery was outside the stent site in 50% of cases. SPECT imaging appears to be accurate to predict significant stenosis in the stented artery, although the most severe stenosis is frequently distant from the stent site.     

Evaluation of myocardial damage using 123I-BMIPP imaging in patients with vasospastic angina

The purpose of this study is to determine whether left ventricular dysfunction following coronary artery spasm by 123I-BMIPP myocardial imaging. To reveal the clinical efficacy of 123I-BMIPP SPECT, 20 patients with vasospastic angina were studied using resting, 3-hour delayed image with 123I-BMIPP and exercise, 3-hour delayed image with 201Tl SPECT. 123I-BMIPP uptake was decreased compared to 201Tl (discordant) in 12 patients (60%) and in 49/100 myocardial segments (49%). The extent and severity score in resting image with 123I-BMIPP were significantly larger than that in delayed image with 201Tl (p < 0.01). In 123I-BMIPP SPECT, the severity score in the latest ischemia were significantly larger than that in others. The incidence of a complete agreement of decreased 123I-BMIPP uptake and coronary artery spasm was significantly higher (75%) than that in 201Tl (28%, p < 0.01). Furthermore, compared to 201Tl uptake, decreased 123I-BMIPP uptake much more corresponded to reduced wall motion in 9 of patients with mismatching. The severity of regional wall motion abnormality was significantly correlated with severity score of 123I-BMIPP. Late redistribution in delayed image with 123I-BMIPP was seen in 6 patients. The regional washout rate and the severity of regional wall motion abnormality in 6 patients was significantly lower than that in others (p < 0.05). Thus, metabolic abnormality assessed by 123I-BMIPP is well associated with left ventricular asynergy and spastic region in patients with vasospastic angina. In conclusion, 123I-BMIPP SPECT may sensitively delineate the impaired myocardium following coronary artery spasm, and it is very useful in diagnosing and estimating the severity of vasospastic angina.