Eliana Reyes

Clinical value, cost-effectiveness, and safety of myocardial perfusion scintigraphy: a position statement

Mortality rates due to coronary artery disease (CAD) have declined in recent years as result of improved prevention, diagnosis, and management. Nonetheless, CAD remains the leading cause of death worldwide with most casualties expected to occur in developing nations. Myocardial perfusion scintigraphy (MPS) provides a highly cost-effective tool for the early detection of obstructive CAD in symptomatic individuals and contributes substantially to stratification of patients according to their risk of cardiac death or nonfatal myocardial infarction. MPS also provides valuable information that assists clinical decision-making with regard to medical treatment and intervention. A large body of evidence supports the current applications of MPS, which has become integral to several guidelines for clinical practice.

Detection of significant coronary artery disease by noninvasive anatomical and functional imaging.

Background—The choice of imaging techniques in patients with suspected coronary artery disease (CAD) varies between countries, regions, and hospitals. This prospective, multicenter, comparative effectiveness study was designed to assess the relative accuracy of commonly used imaging techniques for identifying patients with significant CAD. Methods and Results—A total of 475 patients with stable chest pain and intermediate likelihood of CAD underwent coronary computed tomographic angiography and stress myocardial perfusion imaging by single photon emission computed tomography or positron emission tomography, and ventricular wall motion imaging by stress echocardiography or cardiac magnetic resonance. If ≥1 test was abnormal, patients underwent invasive coronary angiography. Significant CAD was defined by invasive coronary angiography as >50% stenosis of the left main stem, >70% stenosis in a major coronary vessel, or 30% to 70% stenosis with fractional flow reserve ⩽0.8. Significant CAD was present in 29% of patients. In a patient-based analysis, coronary computed tomographic angiography had the highest diagnostic accuracy, the area under the receiver operating characteristics curve being 0.91 (95% confidence interval, 0.88–0.94), sensitivity being 91%, and specificity being 92%. Myocardial perfusion imaging had good diagnostic accuracy (area under the curve, 0.74; confidence interval, 0.69–0.78), sensitivity 74%, and specificity 73%. Wall motion imaging had similar accuracy (area under the curve, 0.70; confidence interval, 0.65–0.75) but lower sensitivity (49%, P<0.001) and higher specificity (92%, P<0.001). The diagnostic accuracy of myocardial perfusion imaging and wall motion imaging were lower than that of coronary computed tomographic angiography (P<0.001). Conclusions—In a multicenter European population of patients with stable chest pain and low prevalence of CAD, coronary computed tomographic angiography is more accurate than noninvasive functional testing for detecting significant CAD defined invasively. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT00979199.

Procedure Guidelines for Radionuclide Myocardial Perfusion Imaging

Radionuclide myocardial perfusion imaging (MPI) is an established and non-invasive imaging technique with diagnostic and prognostic efficacy in the investigation of coronary artery disease. It is the only widely available test for assessing myocardial perfusion directly but there are variations in the way it is performed in different centres. Harmonization of practice, at least at a national level, is therefore essential, and clinical governance now makes it mandatory for practice to be based upon evidence whenever possible [ 1]. This is best achieved by expert analysis of the evidence and to this end the British Nuclear Cardiology Society (BNCS) in association with the British Cardiac Society (BCS) and the British Nuclear Medicine Society (BNMS) have developed procedure guidelines for tomographic myocardial perfusion imaging. A systematic literature search was performed and every effort was made to conform with the AGREE recommendations [ 2]. All recommendations are therefore based on either evidence from clinical studies, previous published guidelines or expert consensus of the writing and advisory groups. The guidelines cover the clinical indications of MPI, the methods used for stress testing, the radiopharmaceuticals and the injected activities and also issues related to acquisition, processing and interpretation of images. They do not cover the benefits or drawbacks of the technique in specific circumstances; neither do they address its cost effectiveness in clinical diagnosis and management nor its potential impact on clinical outcomes. The guidelines aim to assist medical practitioners and other health care professionals in recommending, performing, interpreting and reporting single photon emission computed tomography (SPECT) of myocardial perfusion.

High-Dose Adenosine Overcomes the Attenuation of Myocardial Perfusion Reserve Caused by Caffeine

OBJECTIVES We studied whether an increase in adenosine dose overcomes caffeine antagonism on adenosine-mediated coronary vasodilation. BACKGROUND Caffeine is a competitive antagonist at the adenosine receptors, but it is unclear whether caffeine in coffee alters the actions of exogenous adenosine, and whether the antagonism can be surmounted by increasing the adenosine dose. METHODS Myocardial perfusion scintigraphy (MPS) was used to assess adenosine-induced hyperemia in 30 patients before (baseline) and after coffee ingestion (caffeine). At baseline, patients received 140 microg/kg/min of adenosine combined with low-level exercise. For the caffeine study, 12 patients received 140 microg/kg/min of adenosine (standard) and 18 patients received 210 microg/kg/min (high dose) after caffeine intake (200 mg). Myocardial perfusion was assessed semiquantitatively and quantitatively, and perfusion defect was characterized according to the presence of reversibility. RESULTS Caffeine reduced the magnitude of perfusion abnormality induced by standard adenosine as measured by the summed difference score (SDS) (12.0 +/- 4.4 at baseline vs. 4.1 +/- 2.1 after caffeine, p < 0.001) as well as defect size (18% [3% to 38%] vs. 8% [0% to 22%], p < 0.01), whereas it had no effect on the abnormalities caused by high-dose adenosine (SDS, 7.7 +/- 4.0 at baseline vs. 7.8 +/- 4.2 after caffeine, p = 0.7). There was good agreement between baseline and caffeine studies for segmental defect category (kappa = 0.72, 95% confidence interval: 0.65 to 0.79) in the high-dose group. An increase in adenosine after caffeine intake was well tolerated. CONCLUSIONS Caffeine in coffee attenuates adenosine-induced coronary hyperemia and, consequently, the detection of perfusion abnormality by adenosine MPS. This can be overcome by increasing the adenosine dose without compromising test tolerability.

Multicentre multi-device hybrid imaging study of coronary artery disease: results from the EValuation of INtegrated Cardiac Imaging for the Detection and Characterization of Ischaemic Heart Disease (EVINCI) hybrid imaging population

AIMS Hybrid imaging provides a non-invasive assessment of coronary anatomy and myocardial perfusion. We sought to evaluate the added clinical value of hybrid imaging in a multi-centre multi-vendor setting. METHODS AND RESULTS Fourteen centres enrolled 252 patients with stable angina and intermediate (20-90%) pre-test likelihood of coronary artery disease (CAD) who underwent myocardial perfusion scintigraphy (MPS), CT coronary angiography (CTCA), and quantitative coronary angiography (QCA) with fractional flow reserve (FFR). Hybrid MPS/CTCA images were obtained by 3D image fusion. Blinded core-lab analyses were performed for CTCA, MPS, QCA and hybrid datasets. Hemodynamically significant CAD was ruled-in non-invasively in the presence of a matched finding (myocardial perfusion defect co-localized with stenosed coronary artery) and ruled-out with normal findings (both CTCA and MPS normal). Overall prevalence of significant CAD on QCA (>70% stenosis or 30-70% with FFR≤0.80) was 37%. Of 1004 pathological myocardial segments on MPS, 246 (25%) were reclassified from their standard coronary distribution to another territory by hybrid imaging. In this respect, in 45/252 (18%) patients, hybrid imaging reassigned an entire perfusion defect to another coronary territory, changing the final diagnosis in 42% of the cases. Hybrid imaging allowed non-invasive CAD rule-out in 41%, and rule-in in 24% of patients, with a negative and positive predictive value of 88% and 87%, respectively. CONCLUSION In patients at intermediate risk of CAD, hybrid imaging allows non-invasive co-localization of myocardial perfusion defects and subtending coronary arteries, impacting clinical decision-making in almost one every five subjects.

Myocardial perfusion scintigraphy in Europe 2007: a survey of the European Council of Nuclear Cardiology.

PurposeThis is the second of a series of surveys designed to assess myocardial perfusion scintigraphy (MPS) practice in Europe.MethodsData were collected from 258 centres in 18 countries. The number of MPS studies per million population (pmp) was estimated assuming that the nonresponding centres performed either no studies (lower estimate) or the same number as the responding centres (upper estimate).ResultsThe responding centres served 24% of the population of their countries. The total number of noncardiac nuclear medicine studies was between 2,160 and 8,000 studies pmp. The total number of MPS studies was between 529 and 2,293 pmp. The median number of MPS studies per centre was 571 per year with 57% performing fewer than 500 studies per year and 23% of centres performing fewer than 250 studies per year. There was significant variation between countries, with higher numbers of MPS studies (lower limit of estimate above the mid-range of all countries combined) in Austria, Denmark, Hungary, Portugal and Slovenia, and lower numbers (upper limit of estimate below the mid-range of all countries) in Finland, Norway, Spain and Switzerland. The ratio of MPS to coronary angiography to revascularization procedures was 0.9 to 2.2 to 1. Pharmacological stress was used in 57% and technetium-99m-labelled tracers in 88% of studies. ECG gating was performed in 74% of studies and attenuation correction in 22%.ConclusionMPS utilization in Europe remains low compared with coronary angiography although there has been a 21% increase in the number of studies pmp in centres that reported in both 2005 and 2007. Pharmacological agents continue to be the predominant form of stress. Despite the widespread use of technetium-99m-labelled tracers, ECG gating is not universally performed. As in the 2005 survey, imaging aids such as attenuation and motion correction and prone imaging are not commonly used.

Comparison of 64-slice cardiac computed tomography with myocardial perfusion scintigraphy for assessment of global and regional myocardial function and infarction in patients with low to intermediate likelihood of coronary artery disease

Background. Cardiac computed tomography (CCT) has the potential to assess both coronary anatomy and ventricular function in a single study. We examined the agreement between CCT and myocardial perfusion scintigraphy (MPS) for the assessment of global and regional ventricular function.Methods and Results. Research CCT was performed in 52 patients with a low to intermediate likelihood of coronary artery disease referred for MPS. Left ventricular enddiastolic volume, left ventricular end-systolic volume, left ventricular ejection fraction (LVEF), and myocardial wall motion and thickening were compared between techniques. In addition, myocardial contrast attenuation on CCT was compared with radiotracer uptake on MPS. LVEF values agreed well (mean difference, 4.1%; SD, 15.13%), but CCT left ventricular end-diastolic volume was greater compared with MPS (mean difference, 46.0 mL; SD, 33.34 mL) (P<.001). There was moderate agreement for segmental myocardial motion and thickening, with κ values of 0.57 (95% confidence interval, 0.51–0.63) and 0.47 (95% confidence interval, 0.41–0.53), respectively. Seventeen patients had hypoattenuation in at least 1 myocardial segment on CCT. Three of four patients with concomitant abnormalities of wall motion and thickening on CCT had infarction in the same territory on MPS.Conclusions. There was good agreement for LVEF between CCT and MPS but myocardial volumes differed, and these modalities cannot be used interchangeably. Mild abnormalities of regional function are detected more commonly by CCT than by MPS. Myocardial hypoattenuation on CCT is highly specific for myocardial infarction when associated with reduction of systolic wall thickening and regional wall motion abnormality.

Ischemic Burden by 3-Dimensional Myocardial Perfusion Cardiovascular Magnetic Resonance Comparison With Myocardial Perfusion Scintigraphy

Background—The extent and severity of ischemia on myocardial perfusion scintigraphy (MPS) is commonly used to risk-stratify patients with coronary artery disease. Estimation of ischemic burden by cardiovascular magnetic resonance (CMR) with conventional 2-dimensional myocardial perfusion methods is limited by incomplete cardiac coverage. More recently developed 3-dimensional (3D) myocardial perfusion CMR, however, provides whole-heart coverage. The aim of this study was to compare ischemic burden on 3D myocardial perfusion CMR with 99mTc-tetrofosmin MPS. Methods and Results—Forty-five patients who had undergone clinically indicated MPS underwent rest and adenosine stress 3D myocardial perfusion and late gadolinium enhancement CMR. Summed stress and rest scores were calculated for MPS and CMR using a 17-segment model and expressed as a percentage of the maximal possible score. Ischemic burden was defined as the difference between stress and rest scores. 3D myocardial perfusion CMR and MPS agreed in 38 of the 45 patients for the detection of any inducible ischemia. The mean ischemic burden for MPS and CMR was similar (7.5±8.9% versus 6.8±9.5%, respectively, P=0.82) with a strong correlation between techniques (rs=0.70, P<0.001). In a subset of 33 patients who underwent clinically indicated invasive coronary angiography, sensitivities and specificities of the 2 techniques to detect angiographic coronary artery disease were similar (McNemar P=0.45). Conclusions—3D myocardial perfusion CMR is an alternative to MPS for detecting the presence and rating the severity of ischemia.

Combined coronary and perfusion cardiovascular magnetic resonance for the assessment of coronary artery stenosis.

The purpose of this study was to evaluate the feasibility and accuracy of combined coronary and perfusion cardiovascular magnetic resonance (CMR) in the assessment of coronary artery stenosis. Thirty-five consecutive patients (27 men, eight women, age range 34-81 years), undergoing cardiac catheterization, were assessed with 3D coronary CMR and rest-stress perfusion CMR. Significant coronary stenosis was determined by vessel narrowing or signal loss with coronary CMR, and by abnormal contrast enhancement with perfusion CMR. Coronary artery diameter stenosis greater than 50% was considered significant with conventional cardiac catheterization. Seventeen patients had significant coronary artery disease, and in these there were 35 significant stenoses on cardiac catheterization. All left main stem arteries were normal on both cardiac catheterization and coronary CMR. For the diagnosis of coronary artery stenosis, coronary CMR had a sensitivity of 92% for the left anterior descending artery (LAD), 79% for the right coronary artery (RCA), but only 13% for the circumflex coronary artery (LCX). Perfusion CMR had corresponding sensitivities of 69%, 86%, and 63%, respectively. For all arteries the accuracies for coronary and perfusion CMR were 67% and 72%, respectively. Combining coronary and perfusion CMR improved the accuracy to 77%. These data demonstrate that in patients with suspected coronary artery disease, combined coronary and perfusion CMR is feasible, increases the accuracy of detection of significant coronary stenosis, and offers the possibility of combined anatomical and hemodynamic assessment of coronary artery stenosis.

Guidelines in review: Comparison of the 2014 ACC/AHA guidelines on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery and the 2014 ESC/ESA guidelines on noncardiac surgery: Cardiovascular assessment and management

Two sets of clinical practice guidelines (Table 1) were published in 2014 related to the cardiovascular assessment of patients undergoing noncardiac surgery: one endorsed by the American College of Cardiology and the American Heart Association (2014 ACC/AHA guidelines on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery), and the other by the European Society of Cardiology and the European Society of Anaesthesiology (2014 ESC/ESA guidelines on noncardiac surgery: Cardiovascular Assessment and Management). We have previously summarized the ACC/AHA guidelines in the Journal focusing on the recommendations pertaining to noninvasive imaging and coronary revascularization. Since many of our readers are not familiar with both sets of guidelines, we will present here the recommendations from both documents sideby-side (Tables 2, 3, 4, 5, 6, 7). The Class (I, IIa, IIb, III) and the level of evidence (A, B, C) are shown next to each recommendation. We also include a flowchart comparing the stepwise approach of both guidelines toward the evaluation of patients undergoing noncardiac surgery (Figure 1). Our summary will be followed by 2 editorials: The first by Kristensen 4 summarizes the ESC/ESA guidelines focusing on the changes that have been introduced compared to previous versions of these guidelines. The editorial raises awareness to situations where imaging, angiography, and revascularization are and are not indicated in this setting. The second editorial by Port 5 reflects on the similarities and the differences between the 2 sets of guidelines and the implications of these to clinical care. It highlights situations whereby imaging may be indicated by one set of guidelines but not the other. We hope