Stress Nuclear Myocardial Perfusion Imaging Research Articles

Predictors of Left Main Coronary Artery Disease in the ISCHEMIA Trial

BackgroundDetection of ≥50% diameter stenosis left main coronary artery disease (LMD) has prognostic and therapeutic implications. Noninvasive stress imaging or an exercise tolerance test (ETT) are the most common methods to detect obstructive coronary artery disease, though stress test markers of LMD remain ill-defined. ObjectivesThe authors sought to identify markers of LMD as detected on coronary computed tomography angiography (CTA), using clinical and stress testing parameters. MethodsThis was a post hoc analysis of ISCHEMIA (International Study of Comparative Health Effectiveness With Medical and Invasive Approaches), including randomized and nonrandomized participants who had locally determined moderate or severe ischemia on nonimaging ETT, stress nuclear myocardial perfusion imaging, or stress echocardiography followed by CTA to exclude LMD. Stress tests were read by core laboratories. Prior coronary artery bypass grafting was an exclusion. In a stepped multivariate model, the authors identified predictors of LMD, first without and then with stress testing parameters. ResultsAmong 5,146 participants (mean age 63 years, 74% male), 414 (8%) had LMD. Predictors of LMD were older age (P < 0.001), male sex (P < 0.01), absence of prior myocardial infarction (P < 0.009), transient ischemic dilation of the left ventricle on stress echocardiography (P = 0.05), magnitude of ST-segment depression on ETT (P = 0.004), and peak metabolic equivalents achieved on ETT (P = 0.001). The models were weakly predictive of LMD (C-index 0.643 and 0.684). ConclusionsIn patients with moderate or severe ischemia, clinical and stress testing parameters were weakly predictive of LMD on CTA. For most patients with moderate or severe ischemia, anatomical imaging is needed to rule out LMD. (International Study of Comparative Health Effectiveness With Medical and Invasive Approaches [ISCHEMIA]; NCT01471522)

Incremental value of high-frequency QRS analysis for diagnosis and prognosis in suspected exercise-induced myocardial ischaemia.

Exercise stress testing is used to detect myocardial ischaemia, but is limited by low sensitivity and specificity. The authors investigated the value of the analysis of high-frequency QRS components as a marker of abnormal depolarization in addition to standard ST-deviations as a marker of abnormal repolarization to improve the diagnostic accuracy. Consecutive patients undergoing bicycle exercise stress nuclear myocardial perfusion imaging were prospectively enrolled. Presence of myocardial ischaemia, the primary diagnostic endpoint, was adjudicated using MPI and coronary angiography. Automated high-frequency QRS analysis was performed in a blinded fashion. The prognostic endpoint was major adverse cardiac events (MACEs) during two years of follow-up. Exercise-induced ischaemia was detected in 147/662 patients (22%). The sensitivity of high-frequency QRS was similar to ST-deviations (46% vs. 43%, p=0.59), while the specificity was lower (75% vs. 87%, p<0.001). The combined use of high-frequency QRS and ST-deviations classified 59% of patients as 'rule-out' (both negative), 9% as 'rule-in' (both positive) and 32% in an intermediate zone (one test positive). The sensitivity for 'rule-out' and the specificity for 'rule-in' improved to 63% and 97% compared with ST-deviation analysis alone (both p<0.001). MACE-free survival was 90%, 80% and 42% in patients in the 'rule-out', intermediate and 'rule-in' groups (p<0.001). After adjustment for age, gender, ST-deviations and clinical post-test probability of ischaemia, high-frequency QRS remained an independent predictor for the occurrence of MACEs. The use of high-frequency QRS analysis in addition to ST-deviation analysis improves the diagnostic accuracy during exercise stress testing and adds independent prognostic information.

Impact of the ISCHEMIA Trial on Stress Nuclear Myocardial Perfusion Imaging.

The International Study of Comparative Health Effectiveness with Medical and Invasive Approaches (ISCHEMIA) was a randomized trial of 5,179 patients comparing the effects of optimal medical therapy versus the combination of optimal medical therapy and coronary revascularization on major adverse

Recent Trends Suggest Possible Inappropriate Utilization of Myocardial Perfusion Imaging

PurposeThe aim of this study was to analyze the utilization of elective stress nuclear myocardial perfusion imaging (MPI) in the Medicare population. MethodsNationwide Medicare Part B fee-for-service databases for 2004 to 2016 were reviewed. Current Procedural Terminology codes for stress MPI were selected: standard planar and single-photon emission computed tomography (STD) and PET. Utilization rates per 1,000 Medicare beneficiaries were calculated. Elective examinations were identified using place-of-service codes for private offices and hospital outpatient departments (HOPDs). Medicare physician specialty codes identified the performing physician. Because Medicare Part B databases are complete population counts, sample statistics were not required. ResultsElective STD MPI utilization peaked in 2006 at 74 studies/1,000 and had declined by 36% by 2016. Cardiologists’ share of STD MPI grew from 79% to 87% between 2004 and 2016. Cardiologists perform STD MPI primarily in private offices, where utilization peaked in 2008 and then demonstrated an absolute decline of 28 studies/1,000 by 2016. During this same time period, cardiologists’ use of STD MPI in HOPDs demonstrated an absolute increase of 8.1 studies/1,000. From 2004 to 2016, STD MPI use by radiologists declined by 58%. Elective PET MPI maintained an upward trend, reflecting increasing use by cardiologists in private offices. ConclusionsElective STD MPI use is declining, but cardiologists are performing an increasing share in outpatient settings. The drop in private office STD MPI among cardiologists was far greater than the corresponding increase in its use in HOPDs, suggesting that many studies previously performed in private offices were unindicated. Self-referred PET MPI utilization has rapidly grown in cardiology private offices.

Determining post-test risk in a national sample of stress nuclear myocardial perfusion imaging reports: Implications for natural language processing tools

BackgroundReporting standards promote clarity and consistency of stress myocardial perfusion imaging (MPI) reports, but do not require an assessment of post-test risk. Natural Language Processing (NLP) tools could potentially help estimate this risk, yet it is unknown whether reports contain adequate descriptive data to use NLP. MethodsAmong VA patients who underwent stress MPI and coronary angiography between January 1, 2009 and December 31, 2011, 99 stress test reports were randomly selected for analysis. Two reviewers independently categorized each report for the presence of critical data elements essential to describing post-test ischemic risk. ResultsFew stress MPI reports provided a formal assessment of post-test risk within the impression section (3%) or the entire document (4%). In most cases, risk was determinable by combining critical data elements (74% impression, 98% whole). If ischemic risk was not determinable (25% impression, 2% whole), inadequate description of systolic function (9% impression, 1% whole) and inadequate description of ischemia (5% impression, 1% whole) were most commonly implicated. ConclusionsPost-test ischemic risk was determinable but rarely reported in this sample of stress MPI reports. This supports the potential use of NLP to help clarify risk. Further study of NLP in this context is needed.

Safety and feasibility of adjunctive regadenoson injection at peak exercise during exercise myocardial perfusion imaging: The Both Exercise and Regadenoson Stress Test (BERST) trial

BackgroundThe data existing in the literature regarding the safety of using regadenoson with symptom-limited exercise are limited, which motivated the authors to undertake this randomized study. MethodsWe offered patients scheduled to undergo vasodilator stress nuclear myocardial perfusion imaging the opportunity to exercise instead. Patients who failed to reach target heart rate (THR) were randomized to (1) receive regadenoson at peak exercise or (2) stop exercise and receive regadenoson at rest. Patients who reached THR received a standard Tc-99m sestamibi injection with no regadenoson. Results200 patients were included (66% male, mean age 52.5 ± 13.6). 125 patients (62%) reached THR with exercise alone. All stress protocols were well tolerated, and there were no significant adverse events. There were no statistically significant differences in the extent of perfusion abnormalities, image quality, or rate of referral to cardiac catheterization within 60 days between the groups. In fully adjusted logistic regression models, beta-blocker use and diabetes remained significant univariate predictors of failure to reach THR (OR 0.21, 95% CI 0.1-0.5, P < .0001, OR 0.34, 95% CI 0.2-0.7, P = .004, respectively). ConclusionsA protocol combining regadenoson at peak exercise in patients unable to reach THR with exercise is feasible, well-tolerated, and yields comparable imaging results to a standard regadenoson injection at rest. In addition, pharmacologic stress testing may be over-ordered in current clinical practice, as patients referred for such testing were often able to exercise.

Educational Initiatives for Quality Improvement Projects

Noninvasive imaging has become a cornerstone of the practice of cardiovascular medicine. When properly applied, the information obtained from cardiac imaging studies, integrated with overall clinical assessment, can be used to diagnose disease, determine its functional and physiological impact, assess prognosis, and guide therapeutic decisions. The last 2 decades have seen enormous growth in all medical imaging procedures.1 A major component of this increased utilization was in stress nuclear myocardial perfusion imaging (MPI) single-photon emission-computed tomography (SPECT), which has become one of the most commonly used and effective methods to assess patients with known or suspected coronary artery disease. The reasons for this growth have been, and will continue to be, debated for some time. On the more “positive” side, this growth may have been stimulated by a substantial body of research demonstrating the utility of MPI in a wide variety of clinical scenarios. Moreover, advancements in imaging technology and improved access to care may have been contributory. On the “negative” side, some argue that the growth in imaging has been fueled by misguided financial incentives and the practice of “defensive” medicine. One fact, however, is indisputable: Imaging accounts for a large amount of overall healthcare expenditures, and despite the potential for imaging to reduce downstream costs, control of this escalating cost has become central to public healthcare policy. Accordingly, constraint of this growth of cardiac imaging has become a major effort of the government, medical insurers, and professional societies. What is the best method for controlling the proliferation of cardiac imaging, and how should these methods be used to effect change in physician behavior? Article see p 499 In this issue of Circulation , Gibbons and colleagues2 report on their experience in the implementation of one such methodology, the appropriate use criteria (AUC) for SPECT MPI, in …

Incremental value of combining 64-slice computed tomography angiography with stress nuclear myocardial perfusion imaging to improve noninvasive detection of coronary artery disease

BackgroundTo compare the accuracy of combined 64-slice computed tomography angiography (CTA) and stress nuclear myocardial perfusion imaging (MPI) in the noninvasive detection of coronary artery disease (CAD) with that of 64-slice CTA alone. Methods and resultsOne hundred thirty symptomatic patients with suspected CAD underwent both 64-slice CTA and stress thallium-201 MPI before invasive coronary angiography (ICA). Coronary lesions with ≥50% luminal narrowing were considered as significant stenoses on CTA and ICA. Of 390 arteries in 130 patients, 54 (14%) were nonevaluable by CTA due to severe calcifications, motion artifacts, and/or poor opacification. All nonevaluable arteries were considered positive. The sensitivity, specificity, PPV and NPV were 95%, 80%, 69%, and 97%, respectively, for CTA alone and 94%, 92%, 85%, and 97%, respectively, for CTA with stress nuclear MPI for all nonevaluable arteries on CTA. Per-patient analysis showed significant increase in specificity and PPV. The majority (75%, 9/12) of nonevaluable severely calcified vessels in the left anterior descending artery were positive on stress nuclear MPI, whereas the majority (89%, 8/9) of nonevaluable vessels with motion artifacts in the right coronary artery were negative. ConclusionsCombined CTA and stress nuclear MPI provide improved diagnostic accuracy for the noninvasive detection of CAD.

Risks and Benefits of Coronary Computed Tomography Angiography: A Review

Multislice computed tomography coronary angiography (CTA) is a noninvasive radiology technique that provides high-resolution images of the coronary artery. It has high sensitivity and specificity for coronary stenosis and can be used to rule out significant coronary artery disease (CAD), thereby avoiding the risk of invasive coronary angiography. There is a danger that CTA may be overused as a screening test for CAD in healthy subjects, thereby exposing the patients to the dangers of adverse reactions to iodinated contrast agents and cancer induction from radiation exposure. Consensus document has been published for clinical guidance on when it is appropriate to order a CTA. Comparative studies with stress nuclear myocardial perfusion imaging (MPI) have shown that significant coronary atherosclerosis demonstrated on CTA may not be associated with ischemia in the same region on MPI. Functional stress testing with exercise or pharmacological agents may be indicated as supplement to CTA for prognostic stratification and assessment for revascularization.

Importance of wall motion analysis in the diagnosis of left main disease using stress nuclear myocardial perfusion imaging.

We describe a case of a 54-year-old male who underwent exercise technetium-99m sestamibi myocardial perfusion imaging prior to his renal transplantation. With exercise, the patient's myocardial perfusion imaging did not show any transient or fixed myocardial perfusion abnormalities due to balanced ischemia. However, wall motion analysis showed a new global left ventricular systolic dysfunction on post-exercise images. Coronary angiography showed severe left main coronary lesion involving ostia of left anterior descending, ramus intermedius and left circumflex coronary arteries with moderate right coronary artery disease. If one had used the perfusion imaging alone in this patient, the severe multivessel disease including left main coronary disease could have been missed. In this article we emphasize the importance of wall motion analysis in patients undergoing myocardial perfusion imaging.

Post–myocardial infarction risk stratification with stress nuclear myocardial perfusion imaging versus echocardiography: Separate but not equal

The unique contribution of the study by Candell-Riera et al in this issue of the Journal is the evaluation of the prognostic value of stress nuclear MPI and stress echocardiography in the same post-MI cohort. Importantly, it confirms the valuable information that stress nuclear MPI has to offer for management of post-MI patients and simultaneously underscores the limitations of stress echocardiography for the same application. Although the study has limitations, including its relatively small sample size, these observations are consistent with those of a large body of literature involving thousands of patients. Thus this study supports the use of stress nuclear MPI for the evaluation of the post-MI patient as part of an evidence-based clinical practice and provides further concern regarding the use of stress echocardiography as an alternative imaging modality in this setting. It should serve as a reminder that when it comes to evaluation of the patient with coronary heart disease, not all noninvasive tests are created equal.

Stress nuclear myocardial perfusion imaging versus stress echocardiography: Prognostic comparisons

The use of noninvasive stress cardiac imaging for stratifying risk in patients with known or suspected coronary artery disease is growing as a tool for identification of the subgroup most likely to benefit from the expense and risk of more invasive procedures, including cardiac catheterization and coronary revascularization. In this setting, it is especially important that a test be able to identify patients with sufficiently low risk that clinicians are comfortable in deferring such interventions, especially in those with other markers of increased risk. Previous data have shown that cardiac risk is most closely related to the presence and extent of jeopardized viable myocardium on noninvasive stress cardiac imaging. Although stress echocardiography may have comparable ability to detect coronary artery disease, current data suggest that stress echocardiography detects significantly less jeopardized viable myocardium than stress nuclear myocardial perfusion imaging and consequently fewer patients at risk for cardiac events. Stress nuclear myocardial perfusion imaging may therefore have important advantages for risk stratification and the direction of future care of patients with known or suspected coronary artery disease. Copyright © 2000 by W.B. Saunders CompanyProgress in Cardiovascular Diseases, Vol. 43, No. 3 (November/December), 2000: pp 231-244

Dobutamine stress myocardial perfusion imaging

In patients with limited exercise capacity and (relative) contraindications to direct vasodilators such as dipyridamole or adenosine, dobutamine stress nuclear myocardial perfusion imaging (DSMPI) represents an alternative, exercise-independent stress modality for the detection of coronary artery disease (CAD). Nondiagnostic test results (absence of reversible perfusion defects with submaximal stress) do occur in approximately 10% of patients. Serious side effects during DSMPI are rare, with no death, myocardial infarction or ventricular fibrillation reported in three DSMPI safety reports for a total of 2,574 patients. On the basis of a total number of 1,014 patients reported in 20 studies, the sensitivity, specificity and accuracy of the test for the detection of CAD were 88%, 74% and 84%, respectively. Mean sensitivities for one-, two- and three-vessel disease were 84%, 95% and 100%, respectively. The sensitivity for detection of left circumflex CAD (50%) was lower, compared with that for left anterior descending CAD (68%) and right CAD (88%). The sensitivity of predicting multivessel disease by multiregion perfusion abnormalities varied widely, from 44% to 89%, although specificity was excellent in all studies (89% to 94%). In direct diagnostic comparisons, DSMPI was more sensitive, but less specific, than dobutamine stress echocardiography and comparable with direct vasodilator myocardial perfusion imaging. In the largest prognostic study, patients with a normal DSMPI study had an annual hard event rate less than 1%. An ischemic scan pattern provided independent prognostic value, with a direct relationship between the extent and severity of the perfusion defects and prognosis. In conclusion, DSMPI seems a safe and useful nonexercise-dependent stress modality to detect CAD and assess prognosis.

Lipid risk factor correlates of ischemic heart disease as diagnosed by myocardial perfusion scintigraphy.

Patients with known coronary artery disease frequently change their lifestyles (e.g., diet, exercise, and smoking habit) after the diagnosis is made. Such changes can alter lipid risk factor levels and obscure etiologic risk factor associations with the presence of coronary artery disease. It is therefore preferable to determine the contribution of potential risk factors before the diagnosis of coronary artery disease has been established. In this trial, we used stress nuclear myocardial perfusion imaging to diagnose coronary artery disease in patients presenting for evaluation of chest pain. Two groups of age- and sex-matched patients were identified: a normal group (patients with no evidence of coronary artery disease), and an abnormal group (patients whose scans indicated the presence of significant coronary artery disease due to either fixed or reversible perfusion defects). Blood samples were drawn before scanning and analyzed for lipid risk factors. Compared to the normal group, the abnormal group had higher levels of triglycerides (189±91 vs. 135±51 mg/dL, p=0.003), lower levels of high-density lipoprotein cholesterol (39±9 vs. 45±14 mg/dL, p=0.037), and higher levels of small, dense low-density lipoprotein (LDL(3)) (42±18 vs. 32±13 mg/dL, p=0.007). Total cholesterol, low-density lipoprotein, and lipoprotein(a) levels were similar between groups. These findings suggest that ischemic heart disease, as assessed by myocardial perfusion scintigraphy, is more closely associated with the low high-density lipoprotein/high triglyceride syndrome than with increased low-density lipoprotein or total cholesterol levels. (c) 2000 by CHF, Inc.

Noninvasive Assessment of Coronary Artery Disease in Women After Menopause:

Summary: Cardiovascular disease is the leading cause of death in both men and women. Although the mortality rates from cardiovascular disease had been decreasing among men in America, there has been an increase among women. Early detection of atherosclerotic disease is the cornerstone of treatment and will likely result in a decrease in mortality rates in women. Noninvasive strategies will result in optimal disease detection and will stratify women into groups requiring a more aggressive therapeutic approach versus medical management. Additionally, preventative therapy with hormone replacement in women experiencing postmenopause may require an initial diagnostic assessment of coronary disease before treatment is initiated. This review evaluates the current noninvasive testing available, including exercise electrocardiography, stress nuclear myocardial perfusion imaging, and stress echocardiography.