Donna Polk

ACCF/ASE/AHA/ASNC/HFSA/HRS/SCAI/SCCM/SCCT/SCMR 2011 Appropriate Use Criteria for Echocardiography

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Single photon-emission computed tomography

The current document is an update of an earlier version of single photon emission tomography (SPECT) guidelines that was developed by the American Society of Nuclear Cardiology. Although that document was only published a few years ago, there have been significant advances in camera technology, imaging protocols, and reconstruction algorithms that prompted the need for a revised document. This publication is designed to provide imaging guidelines for physicians and technologists who are qualified to practice nuclear cardiology. While the information supplied in this document has been carefully reviewed by experts in the field, the document should not be considered medical advice or a professional service. We are cognizant that SPECT technology is evolving rapidly and that these recommendations may need further revision in the near future. Hence, the imaging guidelines described in this publication should not be used in clinical studies until they have been reviewed and approved by qualified physicians and technologists from their own particular institutions. 2. INSTRUMENTATION QUALITY ASSURANCE AND PERFORMANCE

ACCF/ASE/AHA/ASNC/HFSA/HRS/SCAI/SCCM/SCCT/SCMR 2011 Appropriate use criteria for echocardiography

The American College of Cardiology Foundation (ACCF), in partnership with the American Society of Echocardiography (ASE) and along with key specialty and subspecialty societies, conducted a review of common clinical scenarios where echocardiography is frequently considered. This document combines and updates the original transthoracic and transesophageal echocardiography appropriateness criteria published in 2007 (1) and the original stress echocardiography appropriateness criteria published in 2008 (2). This revision reflects new clinical data, reflects changes in test utilization patterns,and clarifies echocardiography use where omissions or lack of clarity existed in the original criteria.The indications (clinical scenarios)were derived from common applications or anticipated uses, as well as from current clinical practice guidelines and results of studies examining the implementation of the original appropriate use criteria (AUC).The 202 indications in this document were developed by a diverse writing group and scored by a separate independent technical panel on a scale of 1 to 9,to designate appropriate use(median 7 to 9), uncertain use(median 4 to 6), and inappropriate use (median 1 to 3). Ninety-seven indications were rated as appropriate, 34 were rated as uncertain, and 71 were rated as inappropriate. In general,the use of echocardiography for initial diagnosis when there is a change in clinical status or when the results of the echocardiogram are anticipated to change patient management were rated appropriate. Routine testing when there was no change in clinical status or when results of testing were unlikely to modify management were more likely to be inappropriate than appropriate/uncertain.The AUC for echocardiography have the potential to impact physician decision making,healthcare delivery, and reimbursement policy. Furthermore,recognition of uncertain clinical scenarios facilitates identification of areas that would benefit from future research.

Impact of Coronary Artery Calcium Scanning on Coronary Risk Factors and Downstream Testing: The EISNER (Early Identification of Subclinical Atherosclerosis by Noninvasive Imaging Research) Prospective Randomized Trial

OBJECTIVES We conducted a prospective randomized trial to compare the clinical impact of conventional risk factor modification to that associated with the addition of coronary artery calcium (CAC) scanning. BACKGROUND Although CAC scanning predicts cardiac events, its impact on subsequent medical management and coronary artery disease risk is not known. METHODS We assigned 2,137 volunteers to groups that either did undergo CAC scanning or did not undergo CAC scanning before risk factor counseling. The primary end point was 4-year change in coronary artery disease risk factors and Framingham Risk Score. We also compared the groups for differences in downstream medical resource utilization. RESULTS Compared with the no-scan group, the scan group showed a net favorable change in systolic blood pressure (p = 0.02), low-density lipoprotein cholesterol (p = 0.04), and waist circumference for those with increased abdominal girth (p = 0.01), and tendency to weight loss among overweight subjects (p = 0.07). While there was a mean rise in Framingham Risk Score (FRS) in the no-scan group, FRS remained static in the scan group (0.7 ± 5.1 vs. 0.002 ± 4.9, p = 0.003). Within the scan group, increasing baseline CAC score was associated with a dose-response improvement in systolic and diastolic blood pressure (p < 0.001), total cholesterol (p < 0.001), low-density lipoprotein cholesterol (p < 0.001), triglycerides (p < 0.001), weight (p < 0.001), and Framingham Risk Score (p = 0.003). Downstream medical testing and costs in the scan group were comparable to those of the no-scan group, balanced by lower and higher resource utilization for subjects with normal CAC scans and CAC scores ≥400, respectively. CONCLUSIONS Compared with no scanning, randomization to CAC scanning was associated with superior coronary artery disease risk factor control without increasing downstream medical testing. Further study of CAC scanning, including pre-specified treatment recommendations, to assess its impact of cardiovascular outcomes is warranted.

The metabolic syndrome, diabetes, and subclinical atherosclerosis assessed by coronary calcium.

OBJECTIVES We compared the prevalence and extent of coronary artery calcium (CAC) among persons with the metabolic syndrome (MetS), diabetes, and neither condition. BACKGROUND The prevalence and extent of CAC has not been compared among those with MetS, diabetes, or neither condition. METHODS Of 1,823 persons (36% female) age 20 to 79 years who had screening for CAC by computed tomography, 279 had MetS, 150 had diabetes, and the remainder (n = 1,394) had neither condition. Metabolic syndrome was defined with >or=3 of the following: body mass index >or=30 kg/m(2); high-density lipoprotein cholesterol <40 mg/dl if male or <50 mg/dl if female; triglycerides >or=150 mg/dl; blood pressure >or=130/85 mm Hg or on treatment; or fasting glucose 110 to 125 mg/dl. The prevalence and odds of any and significant (>or=75th percentile) CAC among these groups and by number of MetS risk factors were determined. RESULTS Those with neither MetS nor diabetes, MetS, or diabetes had a prevalence of CAC of 53.5%, 58.8%, and 75.3% (p < 0.001), respectively, among men and 37.6%, 50.8%, and 52.6% (p < 0.001), respectively, among women. Coronary artery calcium increased by the number (0 to 5) of MetS risk factors (from 34.0% to 58.3%) (p < 0.001). Forty-one percent of subjects with MetS had either a >20% 10-year risk of CHD or CAC >or=75th percentile for age and gender. Risk factor-adjusted odds for the presence of CAC were 1.40 (95% confidence interval [CI] 1.05 to 1.87) among those with MetS and 1.67 (95% CI 1.12 to 2.50) among those with diabetes, versus those with neither condition. CONCLUSIONS Those with MetS or diabetes have an increased likelihood of CAC compared with those having neither condition.

Aortic Size Assessment by Noncontrast Cardiac Computed Tomography: Normal Limits by Age, Gender, and Body Surface Area

OBJECTIVES To determine normal limits for ascending and descending thoracic aorta diameters in a large population of asymptomatic, low-risk adult subjects. BACKGROUND Assessment of aortic size is possible from gated noncontrast computed tomography (CT) scans obtained for coronary calcium measurements. However, normal limits for aortic size by these studies have yet to be defined. METHODS In 4,039 adult patients undergoing coronary artery calcium (CAC) scanning, systematic measurements of the ascending and descending thoracic aorta diameters were made at the level of the pulmonary artery bifurcation. Multiple linear regression analysis was used to detect risk factors independently associated with ascending and descending thoracic aorta diameter and exclude subjects with these parameters from the final analysis. The final analysis groups for ascending and descending thoracic aorta included 2,952 and 1,931 subjects, respectively. Subjects were then regrouped by gender, age, and body surface area (BSA) for ascending and descending aorta, separately, and for each group, the mean, standard deviation, and upper normal limit were calculated for aortic diameter as well as for the calculated cross-sectional aortic area. Also, linear regression models were used to create BSA versus aortic diameter nomograms by age groups, and a formula for calculating predicted aortic size by age, gender, and BSA was created. RESULTS Age, BSA, gender, and hypertension were directly associated with thoracic aorta dimensions. Additionally, diabetes was associated with ascending aorta diameter, and smoking was associated with descending aorta diameter. The mean diameters for the final analysis group were 33 +/- 4 mm for the ascending and 24 +/- 3 mm for the descending thoracic aorta, respectively. The corresponding upper limits of normal diameters were 41 and 30 mm, respectively. CONCLUSIONS Normal limits of ascending and descending aortic dimensions by noncontrast gated cardiac CT have been defined by age, gender, and BSA in a large, low-risk population of subjects undergoing CAC scanning.

Patient-centered imaging

The continued success of nuclear cardiology demands ongoing re-evaluation of imaging practices to optimize patient care. The first element of this process is to accurately define candidates for imaging. Appropriate use criteria documents provide such guidelines. A second equally important element is choosing the proper imaging procedure for the individual patient. Tailoring imaging to the patient is critical for providing accurate and clinically meaningful information to the physician. There are several integral components to a successful patient-centered imaging approach. Patient safety is of paramount importance when contemplating any diagnostic and/or therapeutic medical option. For myocardial perfusion imaging (MPI) this approach includes not only the risk of the stress protocol but also the ‘‘risk’’ of performing unnecessary additional procedures or administering inappropriate therapy because of a sub-optimally performed test. High-quality imaging limits the latter through improved diagnostic sensitivity and specificity, enhanced risk stratification, and less intraand inter-observer variability when interpreting clinically significant changes in serial images. Another safety consideration is the risk from radiation exposure which should be weighed in each individual patient prior to initiating a study. There has been a recent dramatic increase in public awareness and media focus on radiation exposure. Consequently, a major factor influencing the choice of MPI protocol is radiopharmaceutical dose. This issue is particularly relevant to younger patients and in women of childbearing potential. However, even in older individuals and in those in whom the risk/benefit ratio is low, radiation exposure should be limited to that dose required to obtain a diagnostic study. Protocols that minimize radiation exposure have been proposed recently by a different ASNC writing group and should be considered when evaluating a patient. The patient radiopharmaceutical doses cited in this article are based upon effective radiation exposure from tissue dose coefficients, using International Commission on Radiological Protection (ICRP) Publication 103 weighting factors. Once safety concerns are addressed, it is critical to ensure that the proper imaging protocol is used to best answer the clinical question at hand. Meeting this priority requires close communication between the referring physician and those performing the test. Finally, it is important to consider cost as well as overall patient convenience and satisfaction. Protocols requiring prolonged or return visits are regarded unfavorably by both patients and their referring physicians and significantly decrease laboratory efficiency. Every effort should be made to streamline procedures. This document will address the advantages and disadvantages of currently available stressor and imaging options as well as provide a framework for imaging specific patients through case-based scenarios.

Thoracic Aortic Calcium Versus Coronary Artery Calcium for the Prediction of Coronary Heart Disease and Cardiovascular Disease Events

OBJECTIVES This study compared the ability of coronary artery calcium (CAC) and thoracic aortic calcium (TAC) to predict coronary heart disease (CHD) and cardiovascular disease (CVD) events. BACKGROUND Coronary artery calcium has been shown to strongly predict CHD and CVD events, but it is unknown whether TAC, also measured within a single cardiac computed tomography (CT) scan, is of further value in predicting events. METHODS A total of 2,303 asymptomatic adults (mean age 55.7 years, 38% female) with CT scans were followed up for 4.4 years for CHD (myocardial infarction, cardiac death, or late revascularizations) and CVD (CHD plus stroke). Cox regression, adjusted for Framingham risk score (FRS), examined the relation of Agatston CAC and TAC categories, and log-transformed CAC and TAC with the incidence of CHD and CVD events and receiver-operator characteristic (ROC) curves tested whether TAC improved prediction of events over CAC and FRS. RESULTS A total of 53% of subjects had Agatston CAC scores of 0; 8% 1 to 9; 19% 10 to 99; 12% 100 to 399; and 8% > or =400. For TAC, proportions were 69%, 5%, 12%, 8%, and 7%, respectively; 41 subjects (1.8%) experienced CHD and 47 (2.0%) CVD events. The FRS-adjusted hazard ratios (HR) across increasing CAC groups (relative to <10) ranged from 3.7 (p = 0.04) to 19.6 (p < 0.001) for CHD and from 2.8 (p = 0.07) to 13.1 (p < 0.001) for CVD events; only TAC scores of 100 to 399 predicted CHD and CVD (HR: 3.0, p = 0.008, and HR: 2.3, p = 0.04, respectively); these risks were attenuated after accounting for CAC. Findings were consistent when using log-transformed CAC and TAC Agatston and volume scores. The ROC curve analyses showed CAC predicted CHD and CVD events over FRS alone (p < 0.01); however, TAC did not further add to predicting events over FRS or CAC. CONCLUSIONS This study found that CAC, but not TAC, is strongly related to CHD and CVD events. Moreover, TAC does not further improve event prediction over CAC.

Relation of thoracic aortic and aortic valve calcium to coronary artery calcium and risk assessment

Aortic calcium, aortic valve calcium (AVC), and coronary artery calcium (CAC) have been associated with cardiovascular event risk. We examined the prevalence of thoracic aortic calcium (TAC) and AVC in relation to the presence and extent of CAC, cardiovascular risk factors, and estimated risk of coronary heart disease (CHD). In 2,740 persons without known CHD aged 20 to 79 years, CAC was assessed by electron beam- or multidetector-computed tomography. We determined the prevalence of TAC and AVC in relation to CAC, CHD risk factors, and predicted 10-year risk of CHD. A close correspondence of TAC and AVC was observed with CAC. TAC and AVC increased with age; by the eighth decade of life, the prevalence of TAC was similar to that of CAC (>80%), and 36% of men and 24% of women had AVC. Age, male gender, and low-density lipoprotein cholesterol were directly related to the likelihood of CAC, TAC, and AVC; higher diastolic blood pressure and cigarette smoking additionally predicted CAC. Body mass index and higher systolic and lower diastolic blood pressures were also related to TAC, and higher body mass index and lower diastolic blood pressure were related to AVC. Calculated risk of CHD increased with the presence of AVC and TAC across levels of CAC. TAC and AVC provided incremental value over CAC in association with the 10-year calculated risk of CHD. If longitudinal studies show an incremental value of aortic and aortic valve calcium over that of CAC for prediction of cardiovascular events, future guidelines for risk assessment incorporating CAC assessment may additionally incorporate the measurement of aortic and/or aortic valve calcium.

Automated quantitation of pericardiac fat from noncontrast CT.

Introduction:Increased abdominal visceral fat has been shown to be a cardiovascular risk factor. Preliminary studies indicate that pericardiac fat (PF) may provide similar information. We aimed to develop new software (QFAT) for automatic quantitation of PF from noncontrast cardiac CT and compare PF measures to other cardiovascular risk factors. Methods:QFAT accepts user-defined range of noncontrast transverse cardiac CT slices, automatically segments the heart, and determines PF volume (PFV) as contiguous pericardial fat voxels. PFV normalized to cardiac volume defines PF ratio (PFR). QFAT and manual processing (MAN) was performed in 105 patients (mean BMI, 27; range, 17–41) by 2 observers. Results:Mean processing time was 20 ± 4 seconds for QFAT, and 9 ± 6 minutes for MAN. There was excellent agreement between QFAT and MAN for PFV (R = 0.98) and PFR (R = 0.98). MAN and QFAT interobserver variability were comparable. Interscan and interscanner variability for PFV and PFR were comparable to corresponding interobserver variability. PFV (R = 0.88, P < 0.0001) and PFR (R = 0.81, P < 0.0001) correlated strongly with abdominal visceral fat area, moderately with BMI (R = 0.58, P < 0.0001 and R = 0.48, P < 0.0001), and weakly with abdominal subcutaneous fat area (R = 0.33, P < 0.0001 and R = 0.32, P = 0.001). Conclusions:PFV and PFR can be accurately and automatically quantified from noncontrast CT acquired for coronary calcium screening and may provide complementary information regarding cardiovascular risk.