Stress Myocardial Perfusion Imaging Studies Research Articles

Optimizing stress-only myocardial perfusion imaging: a clinical prediction model to improve patient selection.

Stress-only single photon emission computed tomography myocardial perfusion imaging (MPI) offers numerous advantages in terms of improved workflow, cost and radiation reduction but is currently not widely utilized due to challenges in selecting appropriate patients for this technique. Data from 5959 individuals were used to derive (N = 4018) and validate (N = 1941) a binomial logistic regression model to predict normal stress MPI studies (stress total perfusion deficit < 4%, ejection fraction ≥ 50%). Model performance was analyzed using receiver operator characteristic curves. A simplified point-scoring system was developed and its impact on imaging workflow was assessed. Significant predictors of abnormal vs. normal stress MPI included male sex, age > 65 years, cardiomyopathy, congestive heart failure, myocardial infarction, angina, and pharmacological stress. The final model and simplified scoring system were associated with areas under the curve of 0.81 (95% CI 0.79-0.83) and 0.80 (95% CI 0.79-0.82) in the validation group, respectively. Use of the scoring system was estimated to result in a decrease of 56.5% in the number of non-contributory imaging studies acquired with minimal patient rescheduling. A prediction tool derived from simple clinical information can identify candidates for stress-only MPI studies with a beneficial impact on departmental workflow.

Diagnostic value of clinical risk scores for predicting normal stress myocardial perfusion imaging in subjects without coronary artery calcium

BackgroundWe evaluated if risk scores commonly used to predict the absence of significant stenosis at coronary computed tomography (CT) angiography are useful to predict a normal stress myocardial perfusion imaging (MPI) study. MethodsOur cohort included a total of 1422 consecutive patients with zero coronary artery calcium score (ZCS) who underwent 82Rb PET/CT for evaluation of suspected coronary artery disease (CAD). Predictive models were constructed as reported by Genders et al. and Alshahrani et al., and the probability of abnormal summed stress score (SSS) and of reduced myocardial perfusion reserve (MPR) based on these risk scores was assessed. ResultsIn the overall population, the prevalence of abnormal SSS was 0.10 and the prevalence of reduced MPR was 0.17 (both P < .001).The observed frequencies of abnormal SSS and reduced MPR vs the probabilities predicted by the Genders and Alshahrani models were above the diagonal identity line, highlighting an underestimation of the observed occurrence by these models. The areas under the receiver operating characteristic curve of the Genders and Alshahrani models indicated lack of discriminative ability for predicting abnormal SSS (0.547 and 0.527) and reduced MPR (0.509 and 0.538). The Hosmer–Lemeshow test revealed that both models underestimated the observed occurrence of abnormal SSS and reduced MPR. ConclusionsAvailable models were unable to identify among patients with ZCS those with a low probability of a normal stress MPI study. Thus, an optimal approach to rule out from MPI patients without detectable coronary calcium still needs to be improved.

Can QT dispersion improve the accuracy of stress ECG TMT in detecting myocardial ischemia in chronic stable CAD patients? A stress myocardial perfusion imaging study

BackgroundQT dispersion (QTd) is related to regional variations in myocardial repolarization. Our study aims to assess the value of QTd in prediction of myocardial ischemia and its severity during stress imaging.We enrolled one hundred patients having stable coronary artery disease (CAD) and fulfilling the “Appropriateness criteria for cardiac radionuclide imaging” (MPI). They were divided into group I including patients with MPI-detected ischemia (50 patients) and group II including patients with normal perfusion scan (50 patients). We excluded unstable CAD and all other causes affecting QTd. During isotope scan, ECGs were taken and QTd was calculated at rest and at maximum heart rate.ResultsQTd was significantly higher in the ischemic group both at rest and exercise (P = 0.000). QTd difference, the difference between QTd at rest and stress, was calculated. QTd difference was significantly lower in normal than in ischemic group (P = 0.003). There was a significant positive correlation between QTd difference and defect size (P = 0.04).ConclusionQTd increases in ischemia and the QTd difference (between rest and stress) correlates positively with severity of ischemia.QTd and QTd difference could be used to improve the accuracy of stress imaging test.

Anomalous right coronary artery with interarterial course depicting an unusual case of an electrical storm: a case presentation

BackgroundThe condition of anomalous aortic origin of the right coronary artery (AAORCA) with an interarterial course leads to few, if any, clinical problems. Malignant presentation of the often non-significant AAORCA associated with conduction system abnormalities is a rare finding. Surgical repair, even for highly symptomatic patients, is still controversial. However, in this case, the surgery brought a paradigm shift in treatment modality, improving the symptoms of this patient.Case presentationWe report a case of a 52-year-old man with severe chest pain and recurrent electrical storms with an implanted cardiac resynchronization therapy defibrillator (CRT-D) device. Coronary angiography and computed tomography (CT) revealed the rare anomalous aortic origin of the right coronary artery (AAORCA) with a high interarterial course between the aorta and the pulmonary trunk. As symptoms typically develop on exertion, placing the patient at an increased risk of ischemic distress, a stress myocardial perfusion imaging study helped to identify his high-risk status. Although patient-specific, a surgical repair was the only concrete step agreed upon after multiple collaborative discussions with the cardiac surgeons. Surgery significantly improved the symptoms, with the patient reporting resolution of his chest pain, as well as no documented inappropriate defibrillator activity on follow-up appointments.ConclusionOne purpose of reporting the case study was to underscore the risk factors associated with AAORCA, challenging claims of its benign nature. This case complements existing findings demonstrating that ischemic distress consequent to the right coronary artery (RCA) compression may precede the rare incidence of an electrical storm. Importantly, the case-study emphasizes the significance of integrated multimodality imaging in clinical practice as well as providing real-world evidence for the efficacy of surgical repair in highly symptomatic patients with AAORCA with an interarterial course.

Temporal trends in stress Myocardial Perfusion Imaging (MPI) studies in patients with Coronary Artery Disease (CAD) and with no CAD among Saudi Arabian’s population

Introduction Previous studies showed that lower risk patients are being referred to stress testing. Few studies suggested that the frequency of abnormal myocardial perfusion imaging (MPI) studies have declined over the past two decades to even less than 10%. However, it is not clear if this is a universal observation. The aim of this analysis is to assess the temporal trends of the prevalence of abnormal and ischemic MPI studies among large consecutive cohort of Saudi Arabia’s population over a period of 11 years. Methodology From a high volume single center registry, we assessed all patients who undergone stress MPI studies between Octobers 2007 to June 2017 for changes in their demographics, baseline clinical information, past cardiac history, and cardiac risk factors. We also compared the trends of the frequency of abnormal and ischemic MPI. The sample was divided into 5 successive temporal subgroups for the purposes of analysis: 2007 to 2008; 2009 to 2010; 2011 to 2012; 2013 to 2014; and 2015 to 2017. Results A total of 13,786 MPI studies were analysed over the specified duration. There was a progressive decline in the prevalence of abnormal MPI in all patients, from 50.8% in 2007 to 32.3% in 2017, (P Conclusion There has been a temporal decline in the prevalence of abnormal and ischemic MPI studies over a period of 11 years. However, this decline is significantly lower than the previously reported from western cohorts.

Safety of vasodilator stress myocardial perfusion imaging in patients with elevated cardiac biomarkers

BackgroundWhile adenosine and dipyridamole as myocardial perfusion imaging (MPI) stress agents have literature supporting their safety in the setting of myocardial infarction (MI), regadenoson does not. Studying a high risk cohort of patients with elevated cardiac biomarkers may shed light on potential safety issues of these agents which might also affect lower risk cohorts. MethodsAll patients who had undergone a clinically indicated stress MPI study at two academic centers from 1/1/2010 through 12/31/2012 with elevated troponin ≤7 days prior to testing were included. The primary endpoint was a composite of death, non-fatal MI, congestive heart failure (CHF), stroke, ventricular arrhythmias, atrial fibrillation/flutter, or atrioventricular block requiring intervention within 24 h of testing. ResultsOf the 703 stress MPI studies that met inclusion criteria, 360 (51.2%), 199 (28.3%), 74 (10.5%), 9 (1.3%), and 61 (8.7%) underwent regadenoson, dipyridamole, adenosine, dobutamine, and exercise stress, respectively. The primary endpoint occurred in 11 (1.6%) patients with an incidence of 1.4% (n = 5), 1.0% (n = 2), 1.4% (n = 1), 11.1% (n = 1), and 3.3% (n = 2) following regadenoson, dipyridamole, adenosine, dobutamine, and exercise stress, respectively (P = 0.137). The adverse events included non-fatal MI in 7 (1.0%) patients, death in 1 (0.1%) patient, CHF in 1 (0.1%) patient, ventricular arrhythmia in 1 (0.1%) patient, and atrial arrhythmia in 1 (0.1%) patient. ConclusionIn the setting of elevated troponin, serious complications associated with either exercise or vasodilator stress testing appear to be relatively rare with no increased risk attributable to a particular vasodilator agent.

Temporal trends of stress myocardial perfusion imaging: Influence of diabetes, gender and coronary artery disease status

IntroductionTemporal trends of myocardial perfusion imaging (MPI) among diabetics and non-diabetics and the influence of gender and prior coronary artery disease (CAD) status has not been previously investigated. Materials and methodsConsecutive patients who underwent clinically indicated stress-MPI over a 17-year period (1996 through 2012) were studied. Data were collected prospectively as a part of the ongoing clinical databases. Study patients were divided into 4 temporal subgroups (1996 to 2000, 2001 to 2004, 2005 to 2008 and 2009 to 2012) to compare the trends of cardiac risk factors and the frequency of abnormal and ischemic MPI. ResultsOf 78,344 total stress MPI studies, 30.2% were in diabetics. The frequency of abnormal MPI studies, while substantially higher in diabetics, significantly declined over time both in diabetics (53.6% in 1996 to 39.8% in 2012) and non-diabetics (37% in 1996 to 27.4% in 2012), despite an increase in the cardiac risk factor profile. Furthermore, among patients with no known CAD, the temporal prevalence of abnormal MPI was highest in diabetic men (57.5% in 1996 to 31.9% in 2012), lowest in non-diabetic women (18.8% in 1996 to 11% in 2012), and both intermediate and comparable in non-diabetic men and diabetic women (36.4% and 35.7% in 1996 and 20.7% and 17.5% in 2012, respectively). ConclusionsDespite a temporal reduction in the prevalence of abnormal studies from 1996 through 2012, stress MPI continues to play an important clinical role, particularly in diabetics, men and patients with known-CAD.

Use of observation followed by outpatient stress testing in chest pain patients with prior coronary artery disease history: An evaluation of prognostic utility

ObjectiveTo determine the outcomes of patients with chest pain (CP) and prior history of coronary artery disease (CAD) managed with observation followed by outpatient stress myocardial perfusion imaging (MPI). MethodsRetrospective analysis of patients with CP managed with observation followed by outpatient stress MPI, comparing cardiovascular (CV) event rates stratified by CAD history. Results375 patients were included: 111 with and 264 without a CAD history. All patients underwent outpatient stress MPI within 72h of observation. MPI identified patients at risk for CV events. However, while patients with negative MPI and without a CAD history had very low rates of short- and long-term CAD events (0.8%, 0.8%, and 1.3% at 30days, 1year, and 3years, respectively), event rates of those with a negative test but a CAD history were significantly higher (2.6%, 5.3%, and 6.6% at 30days, 1year and 3years, respectively; p=0.044 and p=0.034 compared to CAD− patients at 1year and 3years, respectively). In a multivariable logistic regression model, a positive MPI proved to be an independent predictor of long-term CV events in patients with CP and prior CAD. ConclusionObservation followed by stress MPI can effectively risk stratify CP patients with prior CAD for CV risk. These patients are at increased risk of CV events even after a low-risk stress MPI study. Patients presenting with CP and managed with a strategy of observation followed by a negative stress MPI warrant close short- and long-term monitoring for recurrent events.

Abstract 73: Use of an ED- Based Observation Unit Followed by Outpatient Stress Testing in Chest Pain Patients with Prior Coronary Artery Disease History: Evaluation of Safety and Prognostic Utility

Objective: Chest pain (CP) observation units are increasingly being used to efficiently triage patients with CP but without high-risk features such as positive biomarkers or pathologic ECG changes. However, little data is available regarding the use of a CP observation strategy in patients presenting with low-risk CP but with history of prior CAD events. The aim of the present study was to determine the outcomes of patients with CP and established CAD managed with observation followed by outpatient stress myocardial perfusion imaging (MPI) and to determine the prognostic value of this strategy. Methods: Retrospective analysis of patients with CP managed with observation followed by outpatient stress MPI at a single community teaching hospital and followed up for 3 years for CV events (defined as death, MI, or need for urgent revascularization). Follow-up event rates were stratified by CAD history at the time of initial CP evaluation. Results: A total of 375 patients were included: 111 with and 264 without a CAD history. All patients safely completed outpatient stress MPI within 72 hours of observation. Stress MPI effectively identified patients at risk for CV events regardless of CAD history, although patients with CAD history had a significantly higher rate of +MPI (35/111 (31.5%) vs. 28/264 (10.6%) for patients with +CAD vs. [[Unable to Display Character: &amp;#8211;]]CAD history, respectively, p=&lt;0.001). Patients managed in an observation unit followed by a non-ischemic outpatient stress MPI and without a CAD history had, as expected, very low rates of short- and long-term CAD events (2/264 (0.8%), and 3/264 (1.1%) at 1 year and 3 years, respectively). In contrast, follow-up event rates of those patients with a non-ischemic test but a +CAD history were significantly higher (6/111 (5.4%) and 7/111 (6.3%) at 1 year and 3 years, respectively; p=0.044 and p=0.034 compared to CAD- patients). To determine if stress MPI testing contributed independent prognostic information regarding CP patients with a history of CAD, we developed a multivariable logistic regression model using patient demographic and risk factor data as well as MPI results: in this model a positive MPI proved to be a strong independent predictor of long-term CV events (OR=4.75 for CV events at 3yr follow-up, 95% CI 1.35-16.70, p=0.015). Conclusion: A strategy of observation followed by stress MPI can safely and effectively risk stratify CP patients with prior CAD for long-term CV events. However, our data suggests these patients are at increased risk of CV events even after a low-risk follow-up stress MPI study. Thus, patients presenting with CP and managed with a strategy of observation and a non-ischemic stress MPI still warrant close short and long term monitoring for recurrent events.

Evaluation of Molecular Breast Imaging in Women Undergoing Myocardial Perfusion Imaging with Tc-99m Sestamibi

Our objective was to explore the potential benefits of molecular breast imaging (MBI) as a screening technique in women undergoing stress myocardial perfusion studies. MBI was offered to women receiving Tc-99m sestamibi injection for myocardial perfusion stress testing. During the required waiting period after stress isotope injection, MBI was performed using a dedicated breast imaging gamma camera system. MBI examinations were interpreted by breast radiologists, with review of a recent mammogram in cases with positive MBI. Of 322 women enrolled, 313 completed MBI, comprising 5 with known breast cancer, 2 with known high-risk benign breast lesions, and 306 who were asymptomatic for breast disease with a recent negative mammogram. Analysis was limited to the 306 patients with no known breast disease. MBI was positive in 22 of 306, giving a recall rate of 7.2% (95% confidence interval [CI] 4.8-10.6]. MBI detected 4 new cancers, resulting in a supplemental diagnostic yield of 13.1/1000 women screened (95% CI 5.1-33.2). The number of cancers diagnosed per abnormal MBI examinations (PPV(1)) was 18% (4 of 22) (95% CI 7.3-38.5), and the number diagnosed per MBI-prompted biopsies (PPV(3)) was 44% (4 of 9) (95% CI 18.9-73.3). The addition of MBI to clinically indicated stress myocardial perfusion imaging studies in women results in a high diagnostic yield of newly detected breast cancers while generating a low rate of additional unnecessary workup.

Usefulness of Myocardial Perfusion Imaging With Exercise Testing in Children

Myocardial perfusion imaging (MPI) provides additional clinical information on children with cardiac disease but will not benefit children with chest pain and normal cardiac studies. This study reviewed all technetium-99 m ((99m)Tc) sestamibi stress MPI studies between 2004 and 2010 performed in association with graded exercise testing (86% with bicycle ergometer, 14% with treadmill). A positive test was defined as a perfusion defect or abnormal ventricular function response. Clinical records were reviewed, including follow-up assessment to determine accuracy of MPI interpretation. False-positive and false-negative rates were recorded. A total of 197 patients (mean age, 13.4 ± 3.6 years, 70% male) underwent 218 MPI studies. Group A had 42 patients (43 studies) with isolated chest pain and normal studies. Of the 43 studies, 39 had negative results, and 4 had false-positive results. Group B had 155 patients (175 studies) with known or suspected cardiac disease, and 39 tests (33 patients) had positive results. Whereas 32 studies were considered true-positive, 7 were false-positive. There was one false-negative test. According to the findings, (99m)Tc sestamibi MPI studies are clinically useful but not perfect tests in the setting of known or suspected cardiac disease based on clinical evaluation, electrocardiography (ECG), or echocardiography. Children who had isolated chest pain with a normal ECG and echocardiogram often have false-positive studies.

Clinical role of the Duke Activity Status Index in the selection of the optimal type of stress myocardial perfusion imaging study in patients with known or suspected ischemic heart disease

BackgroundExercise treadmill stress myocardial perfusion imaging (MPI) with single photon emission computed tomography is commonly used to evaluate the extent and severity of inducible ischemia as well as to risk stratify patients with suspected and known coronary artery disease (CAD). Failure to reach adequate stress, defined as not attaining age-appropriate metabolic equivalents (METs), can underestimate the extent and severity of ischemic heart disease, resulting in false negative results. This study evaluates the efficacy of the Duke Activity Status Index (DASI), a simple self-administered 12-item questionnaire, as a predictor of METs achieved by treadmill stress testing. MethodsThe DASI was prospectively administered to 200 randomly selected men and women referred to the nuclear cardiology laboratory at New York University Langone Medical Center for stress MPI. Each patient was asked to complete the 12-item DASI questionnaire independently. 136 patients underwent treadmill exercise with MPI and 64 had pharmacologic stress with MPI. The association between exercise capacity in METs as estimated by the DASI questionnaire and performance on the Bruce treadmill protocol in METS was compared using chi-square statistics. ResultsOver 70% of those patients whose DASI score predicted the ability to perform <10 METs were unable to exercise beyond stage 2 of the Bruce protocol (7 METs). For those whose DASI score predicted ability to perform >12.5 METs, over 80% of patients reached >stage 2 of the Bruce protocol with 40% reaching beyond stage 3 (10 METs). When patient age was incorporated into the calculation, a more linear relationship was observed between predicted and obtained METs. ConclusionThe DASI is a simple self-administered questionnaire which is a useful pretest tool to determine a patient’s ability to achieve appropriate METs. In the nuclear cardiology laboratory, the DASI has the potential to guide selection of exercise treadmill vs pharmacologic stress and ultimately improve laboratory efficiency.

Ambulatory Cardiac Single-Photon Emission Computed Tomography at the Primary Care Physician's Office

Ambulatory cardiac single-photon emission computed tomography stress testing for the evaluation of coronary artery disease at the primary care physician's office is increasingly utilized without data supporting its safety. In this 2-year prospective pilot study of 1266 consecutive stress-myocardial perfusion imaging studies done in the primary care physician's office using a mobile nuclear cardiology laboratory, adverse events were mild and rare. There were no recorded events of myocardial infarction, serious arrhythmias, severe bronchospasm, hospitalization, or death. This suggests that this practice is safe in this population with these providers. This finding may not apply to a higher-risk population. Further evaluation of referral appropriateness and long-term prognostic value is needed.

Prognostic predictors and outcomes in patients with abnormal myocardial perfusion imaging and angiographically insignificant coronary artery disease

Abnormal stress myocardial perfusion imaging studies (SMPI) with angiographically insignificant coronary artery disease (ICAD) have often been labeled "false positive" scans. We evaluated the prognostic predictors and outcomes in an unselected patient population having abnormal SMPI and ICAD (study group) over a 24 month period of follow-up. Retrospective study of consecutive patients who had SMPI and subsequent coronary angiography showing ICAD within 6 months of index scan with matched control group with normal scans. Major Adverse Cardiac Events (MACE) were defined as the first occurrence of death or myocardial infarction (MI). Patients were followed up to 24 months from the time of their SMPI to identify the development of MACE. One hundred and twenty five patients formed the study group and one hundred and thirty six patients formed the control group. Over a two-year follow up, approximately 13% of the study group had MACE as compared to 4.2% in the control group (P = .022). Abnormal SMPI, EF < 40% and chronic kidney disease (GFR < 60 ml/min) were independent predictors of MACE in the study group. In multivariate analysis for MACE prediction, chronic kidney disease remained the sole independent predictor regardless of size or severity of perfusion abnormalities (P = <.001). Patients with abnormal SMPI and ICAD have a 13% event rate of MACE over a two-year follow up. CKD seems a very important marker of a higher risk subgroup amongst such patients.

Is the dyspnea during adenosine cardiac stress test caused by bronchospasm?

Background Adenosine cardiac stress is widely used as an alternative to exercise testing during myocardial perfusion imaging (MPI). Dyspnea often accompanies the adenosine stress test. Although known asthmatic patients are excluded from this test because of the danger of bronchospasm, there is incomplete information regarding the role of factors such as chronic obstructive pulmonary disease (COPD) and tobacco smoking in adenosine-induced dyspnea. Patients and Methods A total of 122 consecutive patients (75 male, 47 female; mean age 59 years, SD 10 years) undergoing pharmacologic stress testing with an intravenous infusion of adenosine also had volume-flow spirometry (Vitalograph Compact, Vitalograph Ltd) before, during, and after the test. The indices assessed were forced expiratory volume in one second, its ratio to the forced vital capacity, and peak expiratory flow rate. Results Mild to severe symptoms were experienced by 81% of patients during adenosine infusion. More than half the patients had dyspnea, but there was no associated bronchospasm. Although the patients with COPD showed parameters indicative of bronchial resistance compared with those without this problem, there was no further deterioration after adenosine infusion. Similarly, patients with a history of tobacco abuse, despite showing a tendency toward increasing airways resistance, had no bronchospasm during the administration of adenosine. Conclusions (1) Although dyspnea is a common problem during adenosine stress MPI, it is not associated with any appreciable bronchospasm. (2) COPD and tobacco abuse do not appear to be contraindications to adenosine stress MPI studies. However, it is probably safe to exclude patients with severe COPD from adenosine stress MPI until after further evaluation with larger numbers of patients. (Am Heart J 2001;142:142-5.)

An optimal dual-size vial system for the cost-effective usage of Adenoscan

Background. Adenoscan (Fujisawa USA, Inc., Deerfield, Ill.) has been initially packaged in a 30 ml glass vial for single use only because it contains no preservative. This restricted usage has generated considerable waste and high cost for the patient. Although the new 20 ml vial of Adenoscan provides some reduction in waste, the savings offered by the 20 ml and 30 ml vial system is still not optimal. The purpose of this study was to investigate an optimal dual-size vial system that would provide limited amounts of waste while maintaining its practicality to satisfy different patient populations. Materials and Results. The least waste for each potential combination ( n = 344) of two vials was calculated by assuming that patient weights (30 to 200 kg) follow a normal distribution. The 6 ml and 15 ml vial combination had the least expected waste for lighter patient populations, and the 9 ml and 15 ml vial system had the least expected waste for heavier populations. The calculated wastes for 4207 patients (83 ± 19 kg) undergoing adenosine stress myocardial perfusion studies at the Mayo Clinic were 10.5 ± 9.3 ml (30 ml vial), 5.1 ± 2.9 ml (20 ml and 30 ml vial system), 1.6 ± 1.0 ml (6 ml and 15 ml vial system), and 1.8 ± 1.2 ml (9 ml and 15 ml vial system). Conclusions. In general, both the 6 ml and 15 ml and 9 ml and 15 ml vial systems perform better than either the single 30 ml vial or the 20 ml and 30 ml vial system. Furthermore, the 6 ml and 15 ml vial combination offers the lowest expected waste for the actual patient population that underwent the adenosine stress myocardial perfusion imaging studies at our institution.