Stress SPECT Research Articles

Semiqualitative Visual and Quantitative Morphometric Evaluations of Reduced Scan Time and Wide-Beam Reconstruction in Rest-Gated Stress SPECT Myocardial Perfusion Imaging

SPECT myocardial perfusion imaging (MPI) now accounts for well over 90% of all MPI studies performed in the United States. A means of reducing the acquisition time while maintaining diagnostic-quality images would be beneficial for both patients and nuclear cardiology clinics. Wide-beam reconstruction (WBR) is a processing algorithm that attempts to address the challenge of obtaining diagnostic-quality images with shorter counting times. This study was designed to incorporate semiqualitative assessments (physician rankings of image parameters) into quantitative assessments (morphologic measurements), as other researchers have done, in an effort to compare filtered backprojection (FBP)-the gold standard-with WBR. Forty-seven MPI studies (from 34 men and 13 women) were masked to 3 physicians who qualitatively rated the images for image quality, myocardial normality, lesion reversibility, and treatment recommendation on a scale of 1-5, with 1 representing "good" and 5 representing "poor." Quantitative values for summed stress scores, summed rest scores, summed difference scores (SDS), end-diastolic volume, end-systolic volume, and the ejection fraction were calculated and reported. The semiqualitative analyses of image interpretation indicated that WBR yielded significant improvements over FBP in image quality and showed very good to moderate agreement with FBP among physicians for myocardial normality, lesion reversibility, and treatment recommendation. The quantitative analyses of the morphometric values representing myocardial perfusion, through SDS comparisons, were equivalent for the 2 reconstruction methods. Regression analysis indicated that WBR seemed to underestimate the gated stress-derived FBP ejection fraction by 9%-10%. Overall, the WBR method was equivalent or superior to the FBP reconstruction method for MPI with a rest-gated stress same-day protocol in terms of image quality, interpretation, and SDS. Additionally, the advantage of patient comfort derived from shorter imaging times should help reduce motion artifacts and repeat acquisitions as well as enhance patient care and throughput.

Assessing the Prognostic Value of Cardiovascular Imaging

Cardiovascular imaging has become the focus of attention from both physicians and payers. The former see the potential of newer modalities to permit new and exciting insights into the diagnosis and management of coronary artery disease (CAD), that, in turn, may result in enhanced patient care strategies and new efficient clinical algorithms. On the other hand, payers have understandable concerns about the excessive use and enormous costs associated with cardiovascular imaging. These concerns have been exacerbated by the rapid expansion of the imaging devices used for the assessment of patients with known or suspected CAD. Cardiovascular stress imaging has long been the domain of stress single photon emission computed tomography myocardial perfusion imaging (SPECT MPI) and stress echocardiography wall motion studies. At present, stress positron emission tomography (PET) MPI, cardiac computed tomography coronary angiography (CTA) (and, possibly, stress CT MPI), as well as cardiac magnetic resonance imaging (CMR) MPI and wall motion studies are utilized in daily practice. Whether all of these modalities will be reimbursed in the future is uncertain, but little doubt remains that their rigorous validation will be compulsory. Article see p 1390 Cardiac magnetic resonance imaging is an evolving technique with growing indications within the clinical cardiology setting. Whereas late gadolinium enhancement (LGE) has gained acceptance as an accurate approach for viability assessment, CMR stress imaging use is increasing as well. Nonetheless, stress CMR techniques are in their relative infancy, and evidence is only now beginning to accumulate justifying their use. Whereas several studies have examined the diagnostic accuracy of stress CMR, only recently have sufficient numbers of patients been collected to assess the prognostic value of this approach1–5 (Table).6 The validation of stress CMR is more complex than that of previous modalities, inasmuch as a routine study would include rest function and …

Comparison of low-dose dobutamine stress echocardiography and single photon emission computed tomography and delayed contrast MRI in the diagnosis of myocardial viability: Meta-analysis

Objective To assess the diagnostic value of different imaging methods including low-dose dobutamine stress echocardiography, SPECT and contrast enhancement MRI with Meta-analysis in the diagnosis of myocardial viability. Methods Articles published from 1998 to 2008 were searched in Cochrane library, Medline, Embase database, OVID database and CNKI for relevant English and Chinese articles. According to the criteria for diagnostic research published by Cochrane Method Group on screening and diagnostic tests, each article was critically screened and appraised, including the absolute numbers of true-positive, false-negative, true-negative, and false-positive. Statistical analysis was performed employing Meta-test Heterogeneity was tested, pooled weighted sensitivity and specificity and the corresponding 95% CI were calculated. Characteristic (SROC) curve was performed and the area under the curve was calculated. Finally, sensitivity analysis was performed. Results Twenty-one of 438 retrieved articles were included, in which there were ten articles about Low-dose dubutamine stress echocardiography, and six articles about 99Tcm-MIBI/99Tcm-Tetrofosmin SPECT, and six articles about contrast enhancement MRI, and one of both 99Tcm-MIBI/99Tcm-tetrofosmin SPECT and contrast enhancement MRI. All groups had heterogeneity, and a random effects regression was developed. The pooled weighted sensitivity and specificity and area under SROC curve for low-dose dobutamine stress echocardiography to diagnose myocardial viability was 0.73(0.62-0. 82)/0. 82 (0.77-0. 86) and 87.07% respectively. They were 0. 82 (0. 59-0. 94)/ 0. 77(0. 64-0. 86) and 86. 97% for 99Tcm-MIBI/99Tcm-Tetrofosmin SPECT respectively, while they were 0. 94 (0. 86-0. 97)/0. 75 (0. 66-0. 83) and 91.41% for contrast enhancement MRI respectively. Conclusion As noninvasive testing technologies, low-dose dobutamine stress echocardiography and 99Tcm-MIBI/99Tcm-tetrofosmin SPECT and delayed contrast enhanced MRI allow the identification of viable myocardium, but delayed contrast enhanced MRI showed significant different pooled sensitivity in comparison to low-dese dobutamine stress echocardiography. Key words: Myocardium; Echocardiography; Tomography; emission-computed; single-photon; Magnetic resonance imaging; Meta-analysis

Multicenter investigation comparing a highly efficient half-time stress-only attenuation correction approach against standard rest-stress Tc-99m SPECT imaging

BackgroundNew iterative algorithms for scatter compensation (SC), noise suppression, and depth-dependent collimator resolution (RR) can shorten rest and stress SPECT acquisitions by 50% while maintaining quality and accuracy equivalent to conventional scans. Full-time stress-only myocardial perfusion SPECT is accurate and efficient when combined with line-source attenuation correction (LSAC). We investigated the potential for half-time stress-only LSAC-SPECT by comparing this to conventional rest/stress SPECT in patients imaged for suspected CAD at three different centers. MethodsOne hundred and ten patients (58% men, 53% exercise) had 64 projection rest/stress Tc-99m ECG-gated SPECT with simultaneous Gd-153 LSAC: 18 had ≤5% CAD likelihood and 92 had coronary angiography. The stress scans were retrospectively ‘stripped’ to create equally spaced 32 projection “half-time” (HT) scans for the emission and transmission (TX) projections. Astonish (Philips, Milpitas, CA) processing with AC, SC, and RR was applied to the HT data with the HT TX maps reconstructed using a Bayesian iterative method. The conventional rest/stress image sets processed using filtered back projection and without AC and the HT-AC stress-only images were interpreted in random sequence by consensus of two readers blinded to clinical information in separate reading sessions. ResultsComparing rest/stress FBP and HT-LSAC, stress perfusion quality was excellent/good in 82 and 89% (P = .13); interpretive certainty (definitely normal or abnormal) was 88 and 95% (P = .14); sensitivity was 77 and 83% (P = .38); specificity was 67 and 71% (P = .65); normalcy was 94 and 100% (P = 1.0); SSS for CAD pts was 7.4 vs 7.8 and for non-CAD pts was 0.7 vs 0 (P = .44 and .16, respectively). Mean stress LVEF was 60% in both groups. ConclusionStress-only imaging with HT-LSAC using the Astonish acquisition/processing method provides results equivalent to conventional rest/stress scanning. This new approach has the potential to significantly improve operational efficiency without sacrificing accuracy.

Unusual Finding of Thoracic Kidney on Myocardial Perfusion Imaging Using SPECT/CT

Noncardiac abnormalities are not uncommon in myocardial perfusion imaging. With the advent of SPECT/CT hybrid system, CT could produce high-quality attenuation maps to improve resolution. In addition, extracardiac abnormalities are easily differentiated by using SPECT/CT. We report a 47year-old man who felt chest tightness on exertion for 2 months. He denied hypertension, diabetes mellitus, or hyperlipidemia. Dipyridamole stress and redistribution myocardial SPECT revealed no perfusion defect. However, a retrocardiac mass with focal radioactivity was identified in the projection images, corresponding to a kidney shadow in the low-dose noncontrast CT scan. Subsequent conventional CT scan confirmed the diagnosis of thoracic renal ectopia.

Stress single photon emission computed tomography for detection of coronary artery disease and risk stratification of asymptomatic patients at moderate risk

BackgroundThe American College of Cardiology Foundation/American Society of Nuclear Cardiology appropriateness criteria document assigns single photon emission computed tomography myocardial perfusion imaging (SPECT MPI) a rating of uncertain for detection and risk assessment of coronary artery disease (CAD) in asymptomatic patients at moderate risk. Methods and ResultsThe nuclear cardiology database was used to identify 260 asymptomatic patients (67 ± 8 years, 72% men) without known CAD who were at moderate CAD risk according to the Framingham risk score. SPECT MPI images were categorized using the summed stress score (SSS). Mean follow-up 9.9 ± 3.0 years. Abnormal SPECT MPI scans were present in 142 patients (55%). By SSS categories, SPECT scans were low-risk in 67%, intermediate-risk in 20%, and high-risk in 13% of patients. Overall survival at 10 years was 79%, significantly better than the age- and gender-matched Minnesota general population (P < 0.001). Survival was 60% for patients with high-risk scans (95% CI 45-80%), 79% with intermediate-risk scans (95% CI 69-91%), and 83% with low-risk scans (95% CI 77-88%) (P = 0.03), including 84% (95% CI 77-91%) with normal scans. ConclusionsIn this retrospectively identified group of asymptomatic patients at moderate CAD risk, stress SPECT MPI was effective for the detection and risk stratification of CAD. Average annual mortality was 4.0% in patients with high-risk scans vs 1.6% in patients with normal scans.

Applicability of Appropriateness Criteria for Stress Imaging

Background— Appropriateness criteria for stress imaging have been published to promote the effective use of stress nuclear scintigraphy and stress echocardiography. We sought to evaluate the application of the stress echocardiography appropriateness criteria to patients undergoing stress echocardiography in an academic medical center. Methods and Results— The stress echocardiography criteria were applied to 298 consecutive patients who underwent stress echocardiography. Patients were rated as appropriate, uncertain, inappropriate, or not classifiable. Results were compared with those of a previous analysis in the same patients using the single-photon computed tomography myocardial perfusion imaging (SPECT MPI) criteria. The level of agreement between 2 cardiac nurse abstractors for categorizing appropriateness by the stress echocardiography criteria was good (κ=0.72). Overall, 54% of patients were classified as appropriate, 8% as uncertain, and 19% as inappropriate; 19% were not classifiable. By the SPECT MPI criteria, 64% of patients were classified as appropriate, 9% as uncertain, and 18% as inappropriate; 9% were not classifiable ( P &lt;0.001 compared with stress echocardiography criteria). By the stress echocardiography criteria, 6 clinical situations or indications accounted for more than 90% of the inappropriate tests; most of these involved asymptomatic patients. Conclusions— Applying stress echocardiography appropriateness criteria to a patient population is feasible, although 1 in 5 of our patients was not classifiable. Overall, the stress echocardiography criteria classified patients differently compared with the SPECT MPI criteria. Future refinements of the appropriateness criteria for stress imaging should address gaps in the criteria and disparities between the stress echocardiography and SPECT MPI criteria.

Prognostic value of myocardial perfusion-gated SPECT in patients with ischemic cardiomyopathy.

There are no extensive series in which risk stratification of patients with ischemic cardiomyopathy (IC) is based on their rest and exercise and scintigraphic characteristics. The purpose of our study was to analyze rest and exercise myocardial perfusion-gated SPECT variables for prognosis in patients with ischemic IC. Prospective cohort study. A study was performed in 167 patients with IC who consecutively underwent rest myocardial perfusion-gated SPECT. In addition, stress SPECT was performed on 137 of these patients. During an average follow-up of 2.3 +/- 1.2 years, cardiac mortality (CM) was 17.4%. Independent predictors of CM in rest-gated SPECT were the positive criteria for myocardial viability (P = 0.027; Hazard risk, HR: 5.1; 95% CI: 1.2-21.4). In the 137 patients who underwent stress-gated SPECT, predictors were scintigraphic criteria for viability plus ischemia (P = 0.026; HR: 3.6; 95% CI: 1.16-11.2) and exercise duration < or = 5 minutes (P = 0.04; HR: 2.7; 95% CI: 1.01-7.36). Coronary angiography variables, performed in 111 patients, did not significantly modify the prognostic value of non-invasive testing. Myocardial perfusion-gated SPECT improves prognostic stratification of patients with IC.

CT angiography for evaluation of coronary artery disease in inner-city outpatients: an initial prospective comparison with stress myocardial perfusion imaging

To evaluate the utility of CT coronary angiography (CTA) for demonstrating coronary artery disease in inner-city outpatients, we prospectively compared CTA with stress SPECT myocardial perfusion imaging in an ethnically diverse, gender balanced population. All patients gave written informed consent for this IRB approved, HIPAA compliant study. Sixty-one patients completed both CTA and SPECT. About 67% were ethnic minorities, 51% were women. A stenosis of >or=70% on CTA was considered positive. Results were compared with perfusion defects on SPECT and correlated with clinical endpoints (hospital admissions, cardiovascular events, coronary interventions and deaths). CTA and SPECT data were compared with results of coronary angiography, when performed. There was moderate global agreement of 79% (48/61) between CTA and SPECT, kappa = 0.483 (SE +/- 0.13, P = 0.0001). With SPECT as the reference standard, CTA had sensitivity of 73% (11/15), specificity of 80% (37/46), negative predictive value of 90% (37/41) and positive predictive value of 55% (11/20). Positive SPECT was associated with positive CTA, (P < 0.0001, OR = 22). Eleven (18%) underwent subsequent cardiac catheterization, which was positive in 91% (10/11). CTA and SPECT had positive predictive values of 90 and 83% compared with catheterization. This study lends preliminary evidence to support to the utility of CTA as an alternative modality for the evaluation of CAD in an ethnically diverse, gender balanced inner-city outpatient population. Similar to more homogenous groups, CTA had a high negative predictive value and demonstrated disease occult to SPECT. Further study is necessary to evaluate the impact of CTA on patient outcomes.

Abstract 5754: Cardiac CT Angiography vs. SPECT Perfusion Imaging for the Evaluation of Patients with Acute Chest Pain

BACKGROUND: Over 5 million individuals present to EDs with acute chest pain each year, many of which are hospitalized for serial EKGs and cardiac enzymes followed by stress SPECT imaging. A potential alternative to SPECT is cardiac CT, which provides for the immediate and direct evaluation of coronary artery patency. We sought to determine the concordance between these modalities and the ability of CT to exclude ischemia in patients presenting with acute chest pain. METHODS: We enrolled 368 subjects without a history of hemodynamically significant CAD who presented to the ED with acute chest pain yet had negative initial EKGs and cardiac enzymes. All subjects underwent 64-slice cardiac CTA, the results of which were blinded to caregivers, then were admitted for standard care including diagnostic testing, as deemed clinically warranted by the caregivers. CTA exams were scored as being diagnostically positive or negative for significant stenosis (&gt;50% luminal narrowing) or as non-diagnostic. SPECT exams were scored as diagnostically pos or neg for ischemia or scar or as non-diagnostic (e.g., secondary to submaximal workload or artifact). RESULTS: 151 of the 368 subjects (54±11 yrs, 56% men) had an exercise (n=109), adenosine (n=41), or dobutamine (n=1) SPECT exam as part of their clinical care. 115 (76%) of the SPECT exams were read as diagnostic (7 pos for ischemia, 2 pos for scar, and 106 neg), while 36 (24%) were non-diagnostic. In contrast, 135 of the 151 (89%) of the CT exams were read as diagnostic (17 pos, 118 neg), while only 16 (11%) were non-diagnostic (p &lt;0.001). Among the 105 patients that had both diagnostic CT and SPECT exams, there was agreement between the modalities in 97/105 (92%) of patients. With SPECT defined as the standard for detecting ischemia, absence of significant stenosis on a diagnostic CT had a 98% NPV for excluding ischemia. CONCLUSION: Cardiac CT appears to be as feasible as SPECT imaging in patients with acute chest pain but inconclusive initial ED evaluation and may have a lower rate of non-diagnostic exams. Consistent with the known high NPV of CCT, absence of significant stenosis on cardiac CT predicted the absence of SPECT based ischemia in 98% of subjects. Thus, cardiac CT may be sufficient to exclude ischemia in patients with acute chest pain.

Angina pectoris during daily activities and exercise stress testing: The role of inducible myocardial ischemia and psychological distress

Physicians often consider angina pectoris to be synonymous with myocardial ischemia. However, the relationship between angina and myocardial ischemia is highly variable and we have little insight into the sources of this variability. We investigated the relationship of inducible myocardial ischemia on SPECT stress perfusion imaging to angina reported with routine daily activities during the previous four weeks ( N = 788) and to angina reported during an exercise stress test ( N = 371) in individuals with confirmed or suspected coronary disease referred for clinical testing. We found that angina experienced during daily life is more strongly and consistently associated with psychological distress and the personal threat associated with angina than with inducible myocardial ischemia. In multivariable models, the presence of any angina during routine activities over the prior month was significantly associated with age, perceived risk of myocardial infarction, and anxiety when compared to those with no reported angina in the past month. Angina during daily life was not significantly associated with inducible myocardial ischemia on stress perfusion imaging in bivariate or multivariable models. In contrast, angina experienced during exercise stress testing was significantly related to image and ECG ischemia, though it was also significantly associated with anxiety. These results suggest that angina frequency over the previous four weeks is more strongly associated with personal threat and psychosocial distress than with inducible myocardial ischemia. These results lend support to angina treatment strategies that aim to reduce threat and distress as well as to reduce myocardial ischemia.

35.35: The utility of repeat stress SPECT myocardial perfusion imaging in patients with end stage liver disease

35.35: The utility of repeat stress SPECT myocardial perfusion imaging in patients with end stage liver disease

Quantitative Measures of Coronary Stenosis Severity by 64-Slice CT Angiography and Relation to Physiologic Significance of Perfusion in Nonobese Patients: Comparison with Stress Myocardial Perfusion Imaging

Coronary stenosis severity by 64-slice CT angiography (CTA) is acceptably correlated with intravascular ultrasound. Stress myocardial perfusion imaging using SPECT is an established method for assessment of the functional significance of coronary stenosis. Our aim was to assess a clinical validation of quantitative measurements of coronary stenosis severity by 64-slice CTA and the relation to the physiologic significance of myocardial perfusion. One hundred four patients with suspected coronary artery disease underwent 64-slice CTA and stress 201Tl SPECT. The stenosis severities of 105 coronary lesions assessed by CTA with sufficient image quality were compared with the results of stress 201Tl SPECT. The body mass index (BMI) of the patients was 23.8 kg/m2 (range, 21.1-25.6 kg/m2). Reversible defects began to increase progressively when the area of stenosis was at least 60%, and the prevalence of these reversible defects and their severity significantly increased as the degree of stenosis increased. When stenosis severity by CTA is < 60%, ischemia is seldom observed; when stenosis severity is > or =80%, ischemia is common (86%). For intermediate stenosis severity values of 60%-70%, the prevalence of reversible defects was 9 of 27 vessels (33%), and for stenosis severity values of 70%-80%, the prevalence was 20 of 37 vessels (54%). When evaluating the diagnostic accuracy of stenosis severity by CTA to identify patients with ischemia excluding all nonevaluable vessels, applying stenosis thresholds of >70% results in 79% sensitivity, 92% specificity, 66% positive predictive value, and 96% negative predictive value. A lesion minimal luminal cross-sectional area of < 3.7 mm2 was a good accurate cutoff value for significant coronary narrowing using stress SPECT, with a sensitivity of 88% and specificity of 83% by receiver-operating-characteristic analysis. Despite an excellent negative predictive value to rule out the presence of ischemia, 64-slice CTA alone is a poor discriminator of the functional significance of myocardial ischemia in a highly selected patient population with a low BMI.

Hypertensive response with exercise does not increase the prevalence of abnormal Tc-99m SPECT Stress Perfusion Images

Systemic hypertension and an exaggerated blood pressure (BP) response with exercise have been associated with 'false-positive' findings on stress electrocardiography and echocardiography; however, limited data is available for stress myocardial perfusion imaging (MPI). The purpose of this study was to investigate whether an exaggerated elevation in BP with exercise is associated with an increased prevalence of abnormal MPI. BP responses to exercise were assessed in a cohort of 7,205 patients who underwent stress testing with technetium 99m-SPECT MPI (7/1999-6/2005) for the evaluation of chest pain or dyspnea. A hypertensive response, defined as a peak systolic BP > or = 220 mmHg, occurred in 355 (4.9%) and was not associated with higher rates of ischemic ECG changes (16.1 versus 16.6%; P = .7), differences in Duke treadmill scores (4.7 +/- 4 versus 5.1 +/- 5; P = .3) or an increased prevalence of abnormal perfusion images (30.1% versus 32.9%; P = .3) to those without a hypertensive exercise response. Patients with a hypertensive response and either intermediate or high-risk MPI (on the basis of summed-difference-scores) referred for coronary angiography, had a high prevalence of coronary artery disease which was similar to those without a hypertensive response (88% versus 83%; P = .5). In an analysis of a community-based patient subset, a hypertensive response was not associated with a difference in either all-cause mortality or subsequent myocardial infarction, coronary revascularization or cardiac death (8% versus 9%; P = .7). A hypertensive BP response to exercise is not associated with increased rates of ischemic ECG changes, higher-risk Duke treadmill scores, greater degrees of abnormal MPI or worse clinical outcome.

Heart Failure Improvement after Autologous Bone Marrow Mononuclear Cells (ABMMC) Transplantation.

Background: Pilot studies suggest that intracoronary transplantation of unselected ABMMC cells may improve Left Ventricular Ejection Fraction (LVEF) in heart failure (HF)Methods: 18 patients were enrolled and completed 1 year follow up. Patients underwent SPECT evaluation, all had ejection fraction < 35%, 6 patients were randomly allocated to the control group and 12 in the Bone Marrow Cells (BMC) group, median age 65 years old, male/female ratio 17/1; all with ischemic cardiomyopathy. All of cohort had NYHA class of III with maximal medical therapy and median basal LEVF was 28.38% (SD=6.5%). Median number of mononuclear and CD34+ cells infused were 8.1*108 and 1.2*107 respectively in a 50 cc delivered retrograde via coronary sinus approach using balloon occlusion "over wire" for 8 to 10 minutes. No study related adverse events were observed.Results: After a median time of 21 days, patients in the BMC group had relief of dyspnea symptoms and improvement in functional class. At 1 year, NYHA class improved in 92% of the patients in the BMC group by at least 1 class and no improvement in the control group. Mean improvements of LVEF post BMC transplantation were 6.18% (SD=4.94%) and 6.7% (SD=4.07%) at rest and stress SPECT respectively. Rest LVEF at baseline and after one-year follow up between the BMC and control groups demonstrates significant difference (4.9% vs 1.6%, p=0.006), as well as the comparison of change in stress LVEF in both groups (6.7% vs 0.11%, p<0.001).Conclusions: Infusion of progenitor cells into the coronary sinus is safe and feasible in the ischemic HF. It is associated with significant improvement in symptoms, functional capacity and LVEF. Larger randomized studies are in progress to build upon this pilot study. [Display omitted]

Abstract 1772: Electrocardiographic Unrecognized Myocardial Infarction Risk Stratification: Quantitated SPECT Infarct Size Predicts Mortality Independent of Clinical and Exercise Test Variables

Background : Unrecognized myocardial infarction (UMI), as diagnosed by surveillance electrocardiography (ECG), has the same poor prognosis as recognized (RMI), independent of ejection fraction or ischemia. The value of post UMI risk stratification by infarct size is unknown. Methods : The study group consisted of 5430 patients who underwent 2 day stress (exercise n = 191, pharmacologic n = 155) and rest Tc-99m sestamibi SPECT studies. UMI was diagnosed if ECG showed Q wave MI in the absence of history of MI. SPECT infarct size was quantitated based on a 60% of peak counts threshold method and was expressed as a percentage of the left ventricle (% LV). The association between infarct size and mortality was adjusted for clinical and exercise test prognostic scoring systems. Results : The population consisted of 346 UMI, 628 RMI, and 4456 patients without MI (No MI). Compared to No MI, mortality risk was increased in UMI (RR 1.7, 95% CI 1.6–1.9; p &lt; 0.001) and RMI (RR 1.6, 95% CI 1.4–1.9; p &lt; 0.001) patients. In the UMI group, infarct size was significantly associated with mortality ( p &lt; 0.001), which persisted after adjustment for Mayo prognostic score alone (available in all patients) ( p &lt; 0.001) and for Mayo prognostic score, Framingham risk score, and Duke treadmill score (data available in 137 patients) ( p &lt; 0.001). For every 10% LV increase in infarct size, mortality risk increased 30% (RR = 1.3, 95% CI 1.2–1.5) (see figure ). Conclusions: In patients with UMI, larger quantitated SPECT infarct size predicts increased mortality independent of clinical and exercise test prognostic scoring systems. This finding supports the use of infarct size imaging for risk stratification of UMI patients.

Abstract 2594: Coronary Multidetector Computed Tomography in the Prognostic Assessment of Patients with Equivocal or Mildly Abnormal Non-Invasive Cardiac Stress Tests

Background: Patients with low or moderate pre-test probability of significant coronary artery disease (CAD) and equivocal or mildly abnormal non-invasive cardiac stress tests represent a frequent management challenge. Coronary multidetector computed tomography (MDCT) has been shown to have excellent diagnostic accuracy to exclude the presence of significant CAD. Methods: The study included 218 patients (mean age 59±12 years, 60% male) with equivocal or mildly abnormal exercise electrocardiography (n=93), stress SPECT perfusion scans (n=121), stress echocardiography (n=3) and stress cardiac MRI (n=1). Patients were either asymptomatic (n=113) or had atypical chest pain (n=105). All patients underwent contrast-enhanced 64-slice MDCT coronary angiography and datasets were evaluated for the presence of coronary atherosclerotic plaques and significant coronary artery stenosis. Patients were followed for 8±3 months and the endpoints evaluated were: cardiac death, myocardial infarction, revascularization procedure performed &gt;3 months after MDCT coronary angiography and unstable angina requiring hospitalization. Results: MDCT coronary angiography was either normal (n=90; 41%), demonstrated non-obstructive coronary atherosclerotic plaques (n=66; 30%) or exhibited significant coronary stenosis (n=62; 29%). Event-free survival was 100% for patients with normal coronary angiography, 98% for patients with non-obstructive plaques and 92% for patients with coronary stenosis (log-rank test P=0.01). One patient with a non-obstructive plaque involving the left main coronary artery died following an AMI (hazard ratio, 0.38; 95% confidence interval, 0.04 to 3.24). Among patients with coronary stenosis, 3 underwent revascularization procedures and 2 died (hazard ratio, 12.59; 95% confidence interval, 1.47 to 107.86). Conclusion: Among patients with equivocal or mildly abnormal non-invasive cardiac stress tests, a normal MDCT coronary angiography is associated with a very low risk for subsequent cardiac events. Further studies are necessary to determine the clinical significance of non-obstructive atherosclerotic plaques detected by MDCT coronary angiography in this patient population.

Myocardial perfusion defects and coronary risk factors in symptomatic and asymptomatic elderly women

We investigated the relation between risk factors of coronary artery disease (CAD) and myocardial ischemia detected by (201)Tl SPECT in elderly women. 306 women aged >or=75 yr (79.1 +/- 3.6 yr) who underwent pharmacologic (201)Tl SPECT for suspected CAD based on symptoms or CAD risk factors were included. Coronary risk factors were evaluated by medical records, and included diabetes mellitus (DM), hypertension, hypercholesterolemia, cigarette smoking, greater age (>or=80 yr), and obesity. Summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS) were calculated based on stress and redistribution SPECT images for semi-quantification. The symptomatic group (n = 110) had a 34.5% perfusion defect rate. The asymptomatic group (n = 196) had a significantly lower perfusion defect rate of 16.8%. However, this significantly increased to 29.4% and 22.0% in the presence of diabetes mellitus (DM) and hypertension, respectively. In addition, the summed stress score of asymptomatic patients (12.4 +/- 6.0) was not lower but comparable to that of symptomatic patients (10.0 +/- 6.0). In elderly women suspected of CAD, pharmacologic perfusion imaging can be used to identify myocardial ischemia in patients with angina as well as asymptomatic subjects with concurrent DM or hypertension.

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Dobutamine-induced myocardial infarction with normal coronary arteries during stress SPECT myocardial perfusion imaging

Dobutamine-induced myocardial infarction with normal coronary arteries during stress SPECT myocardial perfusion imaging