Jennifer H. Mieres

Ionizing radiation in cardiac imaging: a science advisory from the American Heart Association Committee on Cardiac Imaging of the Council on Clinical Cardiology and Committee on Cardiovascular Imaging and Intervention of the Council on Cardiovascular Radiology and Intervention.

A preliminary report on medical radiation exposures to the US population based on publicly available sources of data estimated that the collective dose received from medical uses of radiation has increased by >700% between 1980 and 2006.1 Computed tomography (CT) has had an annual growth rate of >10% per year and accounted for ≈50% of the collective dose in 2006. Approximately 65% of the collective CT dose is from studies of chest, abdomen, and pelvis. In 2006, cardiac CT accounted for 1.5% of the collective CT dose; however, utilization of cardiac CT is expected to rise, with the potential to further increase exposure to the population.1 Nuclear medicine studies in the United States have increased by 5% annually to 20 million in 2006 and accounted for ≈25% of the 2006 collective medical radiation dose. Among nuclear medicine studies, cardiac imaging represented 57% of the number of studies and ≈85% of the radiation dose.1 A number of publications on imaging with CT, fluoroscopy, or radioisotopes have emphasized the risks that may be associated with exposure to ionizing radiation.2–4 To make informed decisions concerning the use of medical radiation in imaging procedures, the following are important components: (1) A working knowledge of the principles and uncertainties of the estimation of patient dose and biological risk; (2) a comparison of the risks of radiation exposure with the risks of activities in daily life; and (3) recognition of the potential risk of failing to make important diagnoses or treatment decisions if imaging is not performed because of safety concerns. There is no federal regulation of patient radiation dose, with the exception of mammography. Most federal and state regulations are aimed at equipment performance or the handling of nuclear materials. Therefore, appropriate utilization of the equipment or nuclear material in cardiac …

Percutaneous Coronary Intervention and Adjunctive Pharmacotherapy in Women A Statement for Healthcare Professionals From the American Heart Association

More than 1.2 million percutaneous coronary interventions are performed annually in the United States, with only an estimated 33% performed in women, despite the established benefits of percutaneous coronary intervention and adjunctive pharmacotherapy in reducing fatal and nonfatal ischemic complications in acute myocardial infarction and high-risk acute coronary syndromes. This statement reviews sex-specific data on the safety and efficacy of contemporary interventional therapies in women.

Comparative Effectiveness of Exercise Electrocardiography With or Without Myocardial Perfusion Single Photon Emission Computed Tomography in Women With Suspected Coronary Artery Disease Results From the What Is the Optimal Method for Ischemia Evaluation in Women (WOMEN) Trial

Background— There is a paucity of randomized trials regarding diagnostic testing in women with suspected coronary artery disease (CAD). It remains unclear whether the addition of myocardial perfusion imaging (MPI) to the standard ECG exercise treadmill test (ETT) provides incremental information to improve clinical decision making in women with suspected CAD. Methods and Results— We randomized symptomatic women with suspected CAD, an interpretable ECG, and ≥5 metabolic equivalents on the Duke Activity Status Index to 1 of 2 diagnostic strategies: ETT or exercise MPI. The primary end point was 2-year incidence of major adverse cardiac events, defined as CAD death or hospitalization for an acute coronary syndrome or heart failure. A total of 824 women were randomized to ETT or exercise MPI. For women randomized to ETT, ECG results were normal in 64%, indeterminate in 16%, and abnormal in 20%. By comparison, the exercise MPI results were normal in 91%, mildly abnormal in 3%, and moderate to severely abnormal in 6%. At 2 years, there was no difference in major adverse cardiac events (98.0% for ETT and 97.7% for MPI; P=0.59). Compared with ETT, index testing costs were higher for exercise MPI (P<0.001), whereas downstream procedural costs were slightly lower (P=0.0008). Overall, the cumulative diagnostic cost savings was 48% for ETT compared with exercise MPI (P<0.001). Conclusions— In low-risk, exercising women, a diagnostic strategy that uses ETT versus exercise MPI yields similar 2-year posttest outcomes while providing significant diagnostic cost savings. The ETT with selective follow-up testing should be considered as the initial diagnostic strategy in symptomatic women with suspected CAD. Clinical Trial Registration— http://www.clinicaltrials.gov. Unique identifier: NCT00282711.

Role of Noninvasive Testing in the Clinical Evaluation of Women With Suspected Ischemic Heart Disease A Consensus Statement From the American Heart Association

In recent decades, there has been an appropriate focus on ensuring gender equity in the quantity and quality of evidence to guide female-specific, optimal management strategies for suspected and known ischemic heart disease (IHD). The evolving evidence supports a multifactorial pathophysiology of coronary atherosclerosis that includes obstructive coronary artery disease (CAD) and dysfunction of the coronary microvasculature and endothelium, and therefore, the term IHD best encompasses this varied pathophysiology in women. An overwhelming body of evidence has documented undertreatment and undertesting of women, leading to higher case fatality rates and increased morbid complications among women.1–3 Accordingly, to increase our knowledge base, women were given the status of a priority population, which resulted in federal policy to include proportional representation of females in clinical trials and registries.4 The past decade provided abundant evidence to guide clinical decision making regarding diagnostic testing for suspected IHD. In 2005, the American Heart Association (AHA) published an evidence synthesis on the use of CAD imaging for the evaluation of symptomatic women with suspected myocardial ischemia.5 Numerous reports have since provided additional high-quality evidence, including data on coronary computed tomographic angiography (CCTA) and cardiac magnetic resonance imaging (CMR), which in 2005 were considered research techniques.5 The present statement provides an update to the 2005 document and synthesizes contemporary evidence on appropriate symptomatic female candidates for diagnostic testing, as well as sex-specific data on the diagnostic and prognostic accuracy for exercise treadmill testing (ETT) with electrocardiography, stress echocardiography, stress myocardial perfusion imaging (MPI) with single-photon emission computed tomography (SPECT) or positron emission tomography (PET), stress CMR, and CCTA.5 Within this document, quality evidence is synthesized, and important gaps in knowledge about the assessment of IHD risk in women are identified. The 2005 document included sections on the evaluation of asymptomatic …

Comparative Definitions for Moderate-Severe Ischemia in Stress Nuclear, Echocardiography, and Magnetic Resonance Imaging

The lack of standardized reporting of the magnitude of ischemia on noninvasive imaging contributes to variability in translating the severity of ischemia across stress imaging modalities. We identified the risk of coronary artery disease (CAD) death or myocardial infarction (MI) associated with ≥10% ischemic myocardium on stress nuclear imaging as the risk threshold for stress echocardiography and cardiac magnetic resonance. A narrative review revealed that ≥10% ischemic myocardium on stress nuclear imaging was associated with a median rate of CAD death or MI of 4.9%/year (interquartile range: 3.75% to 5.3%). For stress echocardiography, ≥3 newly dysfunctional segments portend a median rate of CAD death or MI of 4.5%/year (interquartile range: 3.8% to 5.9%). Although imprecisely delineated, moderate-severe ischemia on cardiac magnetic resonance may be indicated by ≥4 of 32 stress perfusion defects or ≥3 dobutamine-induced dysfunctional segments. Risk-based thresholds can define equivalent amounts of ischemia across the stress imaging modalities, which will help to translate a common understanding of patient risk on which to guide subsequent management decisions.

Role of Noninvasive Testing in the Clinical Evaluation of Women With Suspected Coronary Artery Disease

Cardiovascular disease is the leading cause of mortality for women in the United States. Coronary heart disease, which includes coronary atherosclerotic disease, myocardial infarction, acute coronary syndromes, and angina, is the largest subset of this mortality, with >240,000 women dying annually from the disease. Atherosclerotic coronary artery disease (CAD) is the focus of this consensus statement. Research continues to report underrecognition and underdiagnosis of CAD as contributory to high mortality rates in women. Timely and accurate diagnosis can significantly reduce CAD mortality for women; indeed, once the diagnosis is made, it does appear that current treatments are equally effective at reducing risk in both women and men. As such, noninvasive diagnostic and prognostic testing offers the potential to identify women at increased CAD risk as the basis for instituting preventive and therapeutic interventions. Nevertheless, the recent evidence-based practice program report from the Agency for Healthcare Research and Quality noted the paucity of women enrolled in diagnostic research studies. Consequently, much of the evidence supporting contemporary recommendations for noninvasive diagnostic studies in women is extrapolated from studies conducted predominantly in cohorts of middle-aged men. The majority of diagnostic and prognostic evidence in cardiac imaging in women and men has been derived from observational registries and referral populations that are affected by selection and other biases. Thus, a better understanding of the potential impact of sex differences on noninvasive cardiac testing in women may greatly improve clinical decision making. This consensus statement provides a synopsis of available evidence on the role of the exercise ECG and cardiac imaging modalities, both those in common use as well as developing technologies that may add clinical value to the diagnosis and risk assessment of the symptomatic and asymptomatic woman with suspected CAD.

The impact of adjunctive adenosine infusion during exercise myocardial perfusion imaging: Results of the Both Exercise and Adenosine Stress Test (BEAST) trial

BackgroundFailure to achieve an adequate heart rate limits the sensitivity of exercise myocardial perfusion imaging (MPI) for the detection of coronary artery disease. In addition, it is often not possible to discontinue medications that may blunt the heart rate response to exercise, because of conditions such as hypertension or angina. However, if pharmacologic stress testing is performed, the ability to assess functional capacity is lost. Accordingly, we developed a protocol that incorporates adenosine stress with symptom-limited exercise.Methods and ResultsAs part of a multicenter study, 35 patients were enrolled prospectively and underwent both exercise MPI and exercise MPI with a 4-minute adenosine infusion on a separate day. Technetium 99m sestamibi was injected at or near peak exercise (exercise only) and at 2 minutes into the adenosine infusion (combined exercise and adenosine). The perfusion images were interpreted in a blinded fashion. The combined adenosine and exercise protocol was well tolerated. The summed stress scores and summed difference scores were greater in the exercise-plus-adenosine group than in the exercise-only group (10.0 vs 8.5, P =.02, and 4.9 vs 3.3, P =.002, respectively). Exercise time was slightly but significantly less with the exerciseplus-adenosine protocol (8 minutes 46 seconds vs 8 minutes 11 seconds, P =.027).ConclusionA protocol combining 4 minutes of adenosine infusion with symptom-limited exercise was safe and well tolerated. Furthermore, this protocol resulted in a greater amount of myocardial ischemia detected on MPI while allowing for the assessment of functional capacity. A combined exercise and adenosine protocol may be a useful test for patients undergoing MPI who are unlikely to achieve an adequate chronotropic response.

Signs and Symptoms of Suspected Myocardial Ischemia in Women: Results from the What is the Optimal Method for Ischemia Evaluation in WomeN? Trial

BACKGROUND Much of our understanding of gender differences in chest pain was derived from noncontemporary reports. The aim of the current report was to compare the frequency of chest pain by measures of ischemia in 824 women with suspected myocardial ischemia prospectively enrolled in a clinical trial of exercise testing with electrocardiography (ETT-ECG) alone compared to myocardial perfusion single photon emission computed tomography (SPECT) (ETT-MPS). METHODS Women seeking evaluation of chest pain or anginal equivalent symptoms were randomized to ETT-ECG or ETT-MPS with Tc-99m tetrofosmin. The Womens Ischemia Syndrome Evaluation (WISE) and Seattle Angina Questionnaire (SAQ) chest pain and Duke Activity Status Index (DASI) questionnaires were employed in enrolled women. Higher SAQ scores denote improved symptoms or functioning. RESULTS Eight hundred twenty-four women, average age 63 years, at intermediate-high coronary artery disease (CAD) likelihood were enrolled from 43 North American centers. Traditional cardiac risk factors were prevalent, with nearly half of women having a family history of premature coronary disease, hypertension, and hyperlipidemia. Chest pain symptoms occurring at least one to three times per week were reported in 60% of women. An examination of the SAQ domains revealed that although women reported minimal physical limitations (median, interquartile range [IQR] 88, 75-100), there was a greater frequency of stable chest pain symptoms (median, IQR=40, 30-50). The majority of women (79%) reported moderate to heavy physical activity levels at home, with the average ETT and DASI estimated metabolic equivalents (METs) of 8.6±2.6 and 11.5±3.8. Women with more frequent daily episodes of chest pain were more likely to have a lower Duke Treadmill Score (DTS), 1 or mm of ST segment depression, and an abnormal MPS. CONCLUSIONS The current report details a contemporary evaluation of female-specific symptomatology and measures of myocardial ischemia. Women reporting frequent angina were more likely to exhibit ischemia and this may characterize a female-specific typical angina pattern.

Spontaneous Coronary Artery Dissection: Current State of the Science: A Scientific Statement From the American Heart Association

Spontaneous coronary artery dissection (SCAD) has emerged as an important cause of acute coronary syndrome, myocardial infarction, and sudden death, particularly among young women and individuals with few conventional atherosclerotic risk factors. Patient-initiated research has spurred increased awareness of SCAD, and improved diagnostic capabilities and findings from large case series have led to changes in approaches to initial and long-term management and increasing evidence that SCAD not only is more common than previously believed but also must be evaluated and treated differently from atherosclerotic myocardial infarction. High rates of recurrent SCAD; its association with female sex, pregnancy, and physical and emotional stress triggers; and concurrent systemic arteriopathies, particularly fibromuscular dysplasia, highlight the differences in clinical characteristics of SCAD compared with atherosclerotic disease. Recent insights into the causes of, clinical course of, treatment options for, outcomes of, and associated conditions of SCAD and the many persistent knowledge gaps are presented.

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.