ACC/AHA/ASNC guidelines for the clinical use of cardiac radionuclide imaging--executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (ACC/AHA/ASNC Committee to Revise the 1995 Guidelines for the Clinical Use of Cardiac Radionuclide Imaging)

Clinical value of absolute quantification of myocardial perfusion with (15)O-water in coronary artery disease

BACKGROUND

The standard interpretation of perfusion imaging is based on the assessment of relative perfusion distribution. The limitations of that approach have been recognized in patients with multivessel disease and endothelial dysfunction. To date, however, no large clinical studies have investigated the value of measuring quantitative blood flow and compared that with relative uptake.

METHODS AND RESULTS

One hundred four patients with moderate (30%-70%) pretest likelihood of coronary artery disease (CAD) underwent PET imaging during adenosine stress using (15)O-water and dynamic imaging. Absolute myocardial blood flow was calculated from which both standard relative myocardial perfusion images and images scaled to a known absolute scale were produced. The patients and the regions then were classified as normal or abnormal and compared against the reference of conventional angiography with fractional flow reserve. In patient-based analysis, the positive predictive value, negative predictive value, and accuracy of absolute perfusion in the detection of any obstructive CAD were 86%, 97%, and 92%, respectively, with absolute quantification. The corresponding values with relative analysis were 61%, 83%, and 73%, respectively. In region-based analysis, the receiver operating characteristic curves confirmed that the absolute quantification was superior to relative assessment. In particular, the specificity and positive predictive value were low using just relative differences in flow. Only 9 of 24 patients with 3-vessel disease were correctly assessed using relative analysis.

CONCLUSIONS

The measurement of myocardial blood flow in absolute terms has a significant impact on the interpretation of myocardial perfusion. As expected, multivessel disease is more accurately detected.

Non-invasive evaluation of internal thoracic artery anastomosed to the left anterior descending artery with 320-detector row computed tomography and adenosine thallium-201 myocardial perfusion scintigraphy

PURPOSE

We evaluated the relationship between internal thoracic artery (ITA) stenosis anastomosed to the left anterior descending artery (LAD) and the degree of LAD stenosis using 320-detector row computed tomography (320-ADCT) and adenosine thallium-201 myocardial perfusion scintigraphy (Tl-201-MPS).

METHODS

We included 101 patients who underwent coronary artery bypass grafting (CABG) using ITA grafts; 320-ADCT and adenosine Tl-201-MPS were performed 2-3 months after CABG. Clinical parameters, degree of LAD stenosis, and regional myocardial ischemia of the LAD territory were compared between patients without ITA stenosis (Group A) and with ITA stenosis (Group B).

RESULTS

Thirty patients (30%) had ≤75% LAD stenosis, and 9 patients (30%) showed significant ITA stenosis. Regional ischemia was noted in 23 patients (23%). There were no differences in clinical parameters between the 2 groups. Twenty-two patients (24%) in Group A and 8 patients (89%) in Group B had ≤75% LAD stenosis (P <0.002). No Group B patients had regional myocardial ischemia of the LAD territory.

CONCLUSION

We concluded that ≤75% LAD stenosis significantly influences ITA stenosis, without associated regional myocardial ischemia of the LAD territory. Non-invasive 320-ADCT and adenosine Tl-201-MPS for ITA evaluation may be useful for long-term follow-up of patients after CABG.

Plasma osteoprotegerin is related to carotid and peripheral arterial disease, but not to myocardial ischemia in type 2 diabetes mellitus

Background

Cardiovascular disease (CVD) is frequent in type 2 diabetes mellitus patients due to accelerated atherosclerosis. Plasma osteoprotegerin (OPG) has evolved as a biomarker for CVD. We examined the relationship between plasma OPG levels and different CVD manifestations in type 2 diabetes.

Methods

Type 2 diabetes patients without known CVD referred consecutively to a diabetes clinic for the first time (n = 305, aged: 58.6 ± 11.3 years, diabetes duration: 4.5 ± 5.3 years) were screened for carotid arterial disease, peripheral arterial disease, and myocardial ischemia by means of carotid artery ultrasonography, peripheral ankle and toe systolic blood pressure measurements, and myocardial perfusion scintigraphy (MPS). In addition, plasma OPG concentrations and other CVD-related markers were measured.

Results

The prevalence of carotid arterial disease, peripheral arterial disease, and myocardial ischemia was 42%, 15%, and 30%, respectively. Plasma OPG was significantly increased in patients with carotid and peripheral arterial disease compared to patients without (p < 0.001, respectively), however, this was not the case for patients with myocardial ischemia versus those without (p = 0.71). When adjusted for age, HbA1c and U-albumin creatinine ratio in a multivariate logistic regression analysis, plasma OPG remained strongly associated with carotid arterial disease (adjusted OR: 2.12; 95% CI: 1.22-3.67; p = 0.008), but not with peripheral arterial disease or myocardial ischemia.

Conclusions

Increased plasma OPG concentration is associated with carotid and peripheral arterial disease in patients with type 2 diabetes, whereas no relation is observed with respect to myocardial ischemia on MPS. The reason for this discrepancy is unknown.

Trial registration number

at http://www.clinicaltrial.gov: NCT00298844

Comparison of high efficiency CZT SPECT MPI to coronary angiography

BACKGROUND

The recently introduced cadmium zinc telluride (CZT) SPECT cameras have the potential to reduce radiation exposure to patients and shorten imaging time. So far, there has been only one small study comparing the results of high efficiency CZT SPECT myocardial perfusion imaging (MPI) to invasive coronary angiography.

METHODS

All patients who had either a Tc-99m sestamibi or Tl-201 SPECT MPI study using a CZT camera (GE Discovery NM 530c) over a 1-year period followed by a coronary angiogram within 2 months were included. Only patients with a history of CABG surgery were excluded. Standard stress protocols were employed. Rest images were acquired for 5 min and stress supine and prone images for 3 min each. Both MPI studies and coronary angiograms were interpreted by blinded readers. A standard 17-segment model was employed for MPI interpretation, and coronary angiograms were interpreted for the presence of obstructive epicardial coronary artery disease (CAD) defined as ≥70% luminal narrowing. Correlation was based on the ability to diagnose obstructive epicardial CAD.

RESULTS

Of the 3,111 patients who underwent SPECT imaging using the CZT camera during this time period, 230 patients qualified for the correlation study (mean age 64.2 ± 11.0 years old, 69% male, and 49% had a history of intracoronary stenting). Tc-99m was used in 76% vs Tl-201 in 24% of the studies. Exercise stress was performed in 60% of patients and vasodilator pharmacologic stress in 40%. Sensitivity was 95%, normalcy rate was 97%, and accuracy was 69% for detecting obstructive CAD.

CONCLUSIONS

In this so far largest correlation study between coronary angiography and high efficiency CZT SPECT imaging, a high sensitivity and accuracy for detecting obstructive epicardial CAD was found for this new SPECT camera technology.

Estimation of cardiac event risk by gated myocardial perfusion imaging and quantitative scoring methods based on a multi-center J-ACCESS database

BACKGROUND

Myocardial perfusion imaging (MPI) has been used to estimate cardiac event risk. The aim of the present study is to achieve stable risk estimation based on perfusion scoring and a multi-center prognostic database.

METHODS AND RESULTS

Multivariate logistic regression analysis was performed to estimate cardiac event risk based on a J-ACCESS study. A stress-MPI was performed in 45 patients with coronary artery disease (CAD) and in 25 non-CAD patients. Perfusion defect scoring of summed stress score (SSS) was performed by 5 methods: (1) visual scoring; (2) automatic scoring of 3 short-axis and 1 vertical long-axis slices; (3) visual modification of Method 2; (4) automatic polar map scoring based on a Japanese multi-center database; and (5) visual modification of Method 4. Agreement of SSS between 2 observers was good (r=0.87-0.97). Agreement of estimated cardiac event risk between observers and among 5 methods was very good (r=0.99-1.00). Regarding diagnostic accuracy for CAD, Method 5 showed optimal diagnostic yields (sensitivity 84%, accuracy 77%).

CONCLUSIONS

Estimation of cardiac event risk in conjunction with polar map segmentation and common normal databases resulted in stable risk values, and might be used for risk stratification in patients suspected of having CAD.

Nuclear myocardial perfusion imaging with a novel cadmium-zinc-telluride detector SPECT/CT device: first validation versus invasive coronary angiography

PURPOSE

We evaluated the diagnostic accuracy of attenuation corrected nuclear myocardial perfusion imaging (MPI) with a novel hybrid single photon emission computed tomography (SPECT)/CT device consisting of an ultrafast dedicated cardiac gamma camera with cadmium-zinc-telluride (CZT) solid-state semiconductor detectors integrated onto a multislice CT scanner to detect coronary artery disease (CAD). Invasive coronary angiography served as the standard of reference.

METHODS

The study population included 66 patients (79% men; mean age 63 ± 11 years) who underwent 1-day (99m)Tc-tetrofosmin pharmacological stress/rest examination and angiography within 3 months. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) as well as accuracy of the CT X-ray based attenuation corrected CZT MPI for detection of CAD (≥ 50% luminal narrowing) was calculated on a per-patient basis.

RESULTS

The prevalence of angiographic CAD in the study population was 82%. Sensitivity, specificity, PPV, NPV and accuracy were 87, 67, 92, 53 and 83%, respectively.

CONCLUSION

In this first report on CZT SPECT/CT MPI comparison versus angiography we confirm a high accuracy for detection of angiographically documented CAD.

SPECT imaging for detecting coronary artery disease and determining prognosis by noninvasive assessment of myocardial perfusion and myocardial viability

Basic knowledge of active and passive transport mechanisms for concentrating monovalent cations in myocardial cells led to the investigation of the application of radioisotopes of potassium, thallium, rubidium, and ammonia to the in vivo noninvasive assessment of regional myocardial perfusion and viability utilizing gamma camera or positron emission tomographic (PET) imaging technology. Subsequently, technetium-99m (Tc-99m)-labeled isonitriles (sestamibi and tetrofosmin), which bind to mitochondrial membranes, emerged as superior imaging agents with single photon emission tomography (SPECT) imaging. When any of these imaging agents are injected intravenously during either exercise or pharmacologic stress, myocardial defects in tracer uptake represent either abnormal regional flow reserve or myocardial scar reflecting of coronary artery disease (CAD). The major clinical indications for stress SPECT or PET myocardial perfusion imaging are for detection of CAD as the cause of chest pain and risk stratification for prognostication. Patients with normal stress myocardial perfusion scans have an excellent prognosis with <1.0% annual rate future annual death or nonfatal infarction. The greater the extent and severity of ischemic perfusion defects (defects seen on stress images but improve on resting images), the greater the subsequent death or infarction rate during follow-up. Rest imaging alone is performed for determination of myocardial viability in patients with CAD and severe left ventricular dysfunction. Myocardial segments showing >50% uptake compared to normal uptake have a better long-term outcome with revascularization than with medical therapy with enhanced left ventricular function and improved survival. Other applications of SPECT imaging include the evaluation of cardiac sympathetic function, assessment of myocardial metabolism in health and disease, and molecular imaging of coronary atherosclerosis and myocardial stem cell therapy.

Coronary heart disease in the elderly: identifying established and subclinical disease with stress testing

Although cardiovascular disease is a major cause of mortality, morbidity, and healthcare expense in the United States, diagnosis in elderly patients, especially those who are asymptomatic, can be challenging. Noninvasive testing offers an opportunity to identify these patients, but guidelines reflect uncertainty of the impact of diagnosis on long-term outcomes. We review the role of different forms of noninvasive testing in both symptomatic and asymptomatic patients, as well as patients under consideration for elective surgery.

Biweekly rituximab, cyclophosphamide, vincristine, non-pegylated liposome-encapsulated doxorubicin and prednisone (R-COMP-14) in elderly patients with poor-risk diffuse large B-cell lymphoma and moderate to high 'life threat' impact cardiopathy

This Phase II study assessed feasibility and efficacy of a biweekly R-COMP-14 regimen (rituximab, cyclophosphamide, non-pegylated liposome-encapsulated doxorubicin, vincristine and prednisone) in untreated elderly patients with poor-risk diffuse large B-cell lymphoma (DLBCL) and moderate to high ‘life threat’ impact NIA/NCI cardiac comorbidity. A total of 208 courses were delivered, with close cardiac monitoring, to 41 patients (median age: 73 years, range: 62–82; 37% >75 years) at a median interval of 15·6 (range, 13–29) days; 67% completed all six scheduled courses. Response rate was 73%, with 68% complete responses (CR); 4-year disease-free survival (DFS) and time to treatment failure (TTF) were 72% and 49%, respectively. Failures were due to early death (n = 3), therapy discontinuations (no-response n = 2; toxicity n = 6), relapse (n = 6) and death in CR (n = 3). Incidence of cardiac grade 3–5 adverse events was 7/41 (17%; 95% confidence interval: 8–31%). Time to progression and overall survival at 4-years were 77% and 67%, respectively. The Age-adjusted Charlson Comorbidity Index (aaCCI) correlated with failures (P = 0·007) with patients scoring ≤7 having a longer TTF (66% vs. 29%; P = 0·009). R-COMP-14 is feasible and ensures a substantial DFS to poor-risk DLBCL patients who would have been denied anthracycline-based treatment due to cardiac morbidity. The aaCCI predicted both treatment discontinuation rate and TTF.

Relationship between erectile dysfunction and silent myocardial ischemia in type 2 diabetic patients with no known macrovascular complications

INTRODUCTION

Erectile dysfunction (ED) is associated with cardiovascular disease (CVD) because it is highly prevalent among those with cardiovascular risk factors (CVRFs). Moreover, it precedes the development of CVD and is considered a subrogate marker of subclinical CVD.

AIM

The aim of this study was to evaluate the presence of ED among patients with type 2 diabetes (DM2) without macroangiopathy, and to assess the association between ED and other CVRFs, chronic diabetes complications, silent myocardial ischemia (SMI), and peripheral arterial disease (PAD).

METHODS

One hundred fifty-four male patients with DM2 and without clinical evidence of CVD were included in the study. The presence of ED, PAD, SMI, chronic diabetic complications, and other CVRFs was evaluated in these patients.

MAIN OUTCOME MEASURES

PAD; SMI; ED; 24-hour blood pressure Holter; lipid profile; insulin resistance; testosterone; chronic inflammation; nephropathy; retinopathy; neuropathy.

RESULTS

Prevalence of ED was 68.2%. Patients with ED were older and characterized by DM2, systolic blood pressure (BP), retinopathy, and insulin treatment of longer duration than patients without ED, even when adjusting for age was performed. Adjusting for duration of diabetic condition revealed significant differences in age and systolic BP. Independent factors for ED were age (57.7±7.5 years, relative risks [RR 1.1], P=0.003) and duration of diabetes (9[3-15] years, RR 1.1, P=0.006). SMI was detected in 13.6% of patients (18.1% in patients with ED vs. 4.1% in patients without ED). Asymptomatic PAD was detected in 13.2% of subjects (14.4% in patients with ED vs. 10.4% in patients without).

CONCLUSIONS

ED is highly prevalent in DM2, and is associated with the presence of SMI, higher systolic BP and chronic microvascular diabetic complications.

Quantification of myocardial perfusion SPECT using freeware package (cardioBull)

OBJECTIVE

We have developed freeware package for automatically quantifying myocardial perfusion and (123)I-labeled radiopharmaceutical single-photon emission computed tomography (SPECT), which is called "cardioBull". We aim to evaluate diagnostic performance of the detection of coronary artery disease (CAD) on the developed software in comparison with commercially available software package [Quantitative Perfusion SPECT (QPS)].

METHODS

Stress-rest (99m)Tc-sestamibi myocardial perfusion SPECT was performed in 36 patients with CAD and 35 control patients. A ≥ 75% stenosis in the coronary artery was identified by coronary angiography in the CAD group. Segmental perfusion defect score was automatically calculated by both cardioBull and QPS software. Summed stress score (SSS) was obtained to detect CAD by the receiver operator characteristic (ROC) analysis. Areas under the ROC curves (AUC) were calculated in patient-based and coronary-based analyses.

RESULTS

Mean SSSs showed no significant difference between cardioBull and QPS (6.0 ± 7.1 vs. 5.6 ± 7.0). The AUC for cardioBull was equivalent to that for QPS (0.91 ± 0.04 vs. 0.87 ± 0.04, p = n.s.). Sensitivity, specificity, and accuracy for cardioBull were 89, 74, and 82%, respectively. For the regional detection of CAD, the AUC showed largest value in left anterior descending coronary artery (LAD) territory (0.86 ± 0.06 for cardioBull, 0.87 ± 0.06 for QPS, p = n.s.). Sensitivity, specificity and accuracy of cardioBull were 70, 88, and 83% for the LAD; 91, 62, and 66% for the left circumflex coronary artery (LCx); and 78, 69, and 70% for the right coronary artery (RCA), respectively.

CONCLUSIONS

The AUC, sensitivity, specificity and accuracy for the detection of CAD showed high diagnostic performance on the developed software. In addition, the developed software provided comparable diagnostic performance to the commercially available software package.

Noninvasive assessment of coronary artery disease in women: What's next?

Significant progress in research has been made in the areas of sex-specific aspects of cardiovascular disease. Despite these advances, coronary artery disease (CAD) is the leading cause of death of women in the Western world. Over the past decade, the focused research on women at risk for ischemic heart disease has helped to clarify our understanding of some of the sex-specific factors, which are important in detecting CAD. In women, the detection and evaluation of physiologically significant CAD is challenging, especially given that traditional tests designed to detect focal areas of coronary artery stenosis are less sensitive and specific in female patients who have a lower prevalence of obstructive coronary disease, greater burden of symptoms, and a high atherosclerotic burden. In this article, we review the available evidence on the role of contemporary cardiovascular imaging techniques in evaluating ischemic heart disease in women.

[Exclusion of coronary artery disease using cardiac CT. What impact do CT results have on patient management?]

Rapid advancement of multidetector head computed tomography (MDCT) during the past 10 years has facilitated noninvasive evaluation of CAD (coronary artery disease). Since the introduction of 320-row technology, examination of the whole heart in a single heart beat with diagnostic quality has become feasible. Direct imaging of vessel morphology, a high sensitivity for CAD above 96%, and low requirements of patient compliance represent advantages over other imaging modalities, such as MRI (magnetic resonance imaging), scintigraphy, and echocardiography. In some cases radiation exposure can be reduced to an effective dose below 1 mSV.Current data suggest that cardiac CT represents a more effective diagnostic tool than treadmill testing in order to decide whether cardiac catheterization is indicated. Treadmill testing has been an integral procedure of cardiac examinations for decades, although sensitivity for detecting CAD is as low as 70%.Cardiac CT represents a rather new modality and is almost exclusively performed in diagnostic imaging centers. Innovative concepts in the evaluation of CAD including CT are expected. Some authors propose cardiac CT as a major diagnostic tool for the exclusion of CAD. MRI, scintigraphy, or echocardiography in combination with a stress test remain important procedures in order to evaluate the hemodynamic relevance of coronary artery stenosis. Treadmill testing prior to cardiac CT has become questionable.The future role of cardiac CT in CAD in "change of management" concepts is promising. In order to optimize decisions of patient management on the basis of a cardiac CT examinations, awareness of current data is mandatory for the referring clinician and the performing radiological department.

[Non-invasive diagnostics of chronic stable coronary artery disease: evidence-based and non-evidence-based diagnostic algorithms]

In Germany, every second left heart catheterization has no immediate interventional or surgical consequence. One main reason for this limited quality of indication of many left heart catheterizations is presumably the inaccuracy of preinvasive testing that is mainly based on clinical evaluation and exercise ECG in Germany. However, exercise electrocardiography has several limitations. The central issues are the inability to exercise in many, especially elderly patients, and the missing interpretability of the stress ECG in cases with already pathological rest ECG. In 2006, the "Nationale Versorgungsleitlinie Chronische KHK (NVL KHK)" was published in Germany, adopting for the first time the evidence-based algorithms of the American College of Cardiology/American Heart Association (ACC/AHA) guidelines for non-invasive stress testing and complementary stress imaging. Stress imaging methods considered comparable and interchangeable are the following: stress echocardiography combined with physical or pharmacological stress testing, myocardial perfusion imaging with physical or pharmacological stress testing, dobutamine stress magnetic resonance imaging (DSMR), or myocardial perfusion magnetic resonance imaging (MRI). Basically, no stress imaging method is definitely superior to the others, each method has its own advantages and disadvantages that should be considered and adjusted to the individual patient. Of pivotal importance of all stress imaging methods is the high negative predictive value of 99% of a normal study predicting a very low (< 1%) cumulative likelihood of cardiac death or myocardial infarction for at least the next 12 months. Hence, in most clinical circumstances, coronary angiography is not necessary during the 12 months subsequent to a normal stress imaging study. In contrast to these established and evidence-based recommendations of the "Nationale Versorgungsleitlinie Chronische KHK" mainly focusing on ischemia stress imaging, many diagnostic centers have developed their own non-evidence based algorithms. In these non-evidence based algorithms the morphology-oriented non-invasive CT coronary angiography has taken over the diagnostic part of evidence-based ischemia stress imaging. However, beyond the scientifically established prognostic value of calcium scoring, there is so far no scientific evidence showing that morphology-oriented CT coronary angiography protocols are superior to functional stress imaging. A new innovative approach of staged non-invasive diagnostics for patients with intermediate likelihood (10-90%) of coronary artery disease are the 2010 recommendations of the National Institute for Health and Clinical Excellence (NICE) guiding the National Health Service (NHS) in the United Kingdom. Following this guidance, in patients with an estimated likelihood of CAD of 10-29% CT calcium scoring should be offered as first-line method, in patients with an estimated likelihood of CAD of 30-60% non-invasive functional imaging should be offered primarily, and in patients with an estimated likelihood of CAD of 61-90%, as in patients with an estimated likelihood of CAD of more than 90%, invasive coronary angiography should be preferred.

Cardiovascular outcomes are predicted by exercise-stress myocardial perfusion imaging: Impact on death, myocardial infarction, and coronary revascularization procedures

BACKGROUND

The aim of this study was to determine the impact of myocardial perfusion imaging (MPI) on the outcomes of death, myocardial infarction (MI), and late coronary revascularization procedures.

METHODS

In patients undergoing exercise-stress MPI (January 1, 2003-March 31, 2007), we determined the impact of summed stress score (SSS) and percent left ventricular (LV) ischemia on (a) death or MI and (b) composite of death, MI, or late coronary revascularization occurring more than 90 days post-MPI.

RESULTS

During 35,007 person-years of follow-up among 9,605 patients (mean ± SD age 54.4 ± 13.2 years, 60.3% men), there were 290 deaths, 175 MIs, and 525 coronary revascularization procedures. Of those who attained ≥10 metabolic equivalents (METS) workload, major stress perfusion defects (SSS ≥7) were present in 4.2% overall and in 3.7% without ST-segment shifts, whereas large ischemic defects (≥10% LV ischemia) were present in 1% overall and 0.7% without ST-segment shifts. For those with 1% to 4%, 5% to 9%, and ≥10% LV ischemia, adjusted hazard ratios were 1.40 (95% CI 1.13-1.73, P = .002), 2.07 (95% CI 1.56-2.74, P < .001), and 3.03 (95% CI 2.21-4.16, P < .001) for the outcome of late revascularization, MI, or death versus no ischemia. Summed stress scores ≥7 were associated with increased risk of death or MI, with an adjusted hazard ratio of 1.57 (95% CI 1.16-2.13, P = .004) compared with those with no stress perfusion defects.

CONCLUSION

Although workload ≥10 METS conferred lower frequency of major ischemia (≥10%), %LV ischemia predicted the occurrence of cardiovascular events and death (eg, MI, late coronary revascularization, or death). Presence of a large stress perfusion defect (SSS ≥7) predicted increased risk of MI or death.

Sex-specific normal limits of left ventricular ejection fraction and volumes estimated by gated myocardial perfusion imaging in adult patients in Taiwan: a comparison between two quantitative methods

BACKGROUND

The left ventricular (LV) ejection fraction (EF) and end-diastolic and end-systolic volumes are strong predictors for prognosis of cardiac death. Quantitative-gated myocardial perfusion single-photon emission computed tomography (SPECT) is widely used to measure LV functional parameters. However, systematic differences may exist between referred populations. We sought to derive sex-specific normal values for LV functional parameters obtained using two quantitative methods.

METHODS

Among 1044 consecutive patients who underwent dipyridamole stress myocardial perfusion-gated 201Tl SPECT in 2008, a total of 140 (56 men) with normal perfusion imaging were selected. None had cardiac diseases or experienced cardiac events during 1-year follow-up. LV EF and end-diastolic and end-systolic volumes were calculated by quantitative-gated SPECT (QGS) and four-dimensional-myocardial single photon emission computed tomography (4D-MSPECT), respectively.

RESULTS

There was excellent intrareader and interreader reproducibility for both QGS and 4D-MSPECT algorithms. The differences in LV volumes and EF between the software packages were small. High prevalence of small heart was noted in the study population, especially in women (>60%). Volumetric measures were significantly greater (P<0.001) in men than in women, even after adjustment for body surface area. Women had a higher LV EF than men when using QGS methods, but not when using the 4D-MSPECT method. Compared with 4D-MSPECT, sex remained significantly associated with EF determined by QGS methods, independent of age and body weight.

CONCLUSION

LV functional parameters determined by means of gated 201Tl SPECT need to be corrected for sex and algorithms. Separate reference values of LV EF and volumes need to be applied in both women and men depending on the software package used.

Prognostic value of demographic factors, pre-test probability scoring, exercise test diagnosis, and inability to exercise in patients with recent onset suspected cardiac chest pain

Aims: To assess the prognostic value of an inconclusive exercise test or inability to exercise in patients with recent onset suspected cardiac chest pain and to determine the independent predictors of events in these patients.

Methods: This was an observational follow-up study of patients presenting to a rapid access chest pain clinic with a history of recent-onset suspected cardiac chest pain as referred by the family practitioner. The main outcome measure was a composite endpoint of death and acute coronary syndrome hospital admission.

Results: The study cohort consisted of 1851 patients in whom a total of 147 events were recorded during a mean follow-up period of 4.1 ± 1.1 years. Those with events were significantly older (65.1 ± 12.5 years versus 56.4 ± 13.2 years, p < 0.001), had higher mean pre-test probability of coronary artery disease (CAD), and had higher prevalence of diabetes (18.4% vs. 13.6%, p < 0.001), hypertension (55.8% vs. 38.7%, p < 0.001), and smoking (36.7% vs. 25.4%, p = 0.03) than those without events. These patients were also more likely to have a positive exercise electrocardiogram (ECG) (15.6% vs. 8.6%, p < 0.001) or not have a diagnostic exercise test because of an inconclusive result or inability to exercise (60.5% vs. 28.6%, p < 0.001). Cox multivariate regression analysis showed that age (hazard ratio, HR 1.03, p < 0.001), pre-test probability of CAD (HR 1.08, p = 0.04), positive exercise ECG (HR 2.94, p < 0.001), and an inconclusive test or inability to exercise (HR 3.45, p < 0.001) were independent predictors of events.

Conclusions: In patients with recent onset suspected cardiac chest pain, not having a diagnostic exercise ECG because of an inconclusive test or inability to exercise is an independent predictor of events and has similar prognostic implications to a positive exercise ECG. In addition, pre-test probability estimation at baseline is a robust indicator of clinical outcome. Future models of care need to incorporate early and increased access to non-exercise cardiac imaging techniques in order to meet the needs of this high-risk subgroup of patients.

Fusion of MR coronary angiography and viability imaging: feasibility and clinical value for the assignment of myocardial infarctions

PURPOSE

To investigate the feasibility of image fusion of MR-coronary angiography (MRCA) and delayed gadolinium enhancement imaging (LGE) and to assign areas of myocardial infarction to the corresponding supplying coronary arteries.

MATERIALS AND METHODS

An interactive segmentation of the coronary arteries was performed in MRCA data sets (n=25). The LGE slices were matched onto the vessel segmentation to perform a fused analysis of coronary artery anatomy and LGE. The results were compared to the segmental model recommended by the American Heart Association (AHA). Standard of reference was the identification of the culprit lesion in the invasive coronary angiography (CA) (n=20).

RESULTS

The fused analysis allowed the assignment of MI to the supplying coronary artery in 13/20 patients. The sensitivities/specificities for the assignment of MI to the three main vessels were: LAD 63%/100%, LCX 75%/100%, and RCA 56%/100%, respectively. Using the AHA segmental model the sensitivities/specificities for the correct assignment of MI to the three main vessels were: LAD 88%/58%, LCX 94%/75%, and RCA 77%/73%, respectively.

CONCLUSION

Fusion images of MRCA and LGE provides added diagnostic information in the effort to determine the epicardial vessels responsible for the postischemic myocardial injury and therefore might be helpful to establish appropriate future therapeutic steps.

Prognostic value of gated myocardial perfusion imaging for asymptomatic patients with type 2 diabetes: the J-ACCESS 2 investigation

OBJECTIVE

Individuals with type 2 diabetes are at high risk for cardiovascular events. We evaluated the prognostic value of gated myocardial perfusion single-photon computed tomography (SPECT) for asymptomatic diabetic patients in a Japanese population.

RESEARCH DESIGN AND METHODS

Asymptomatic patients (n=485) aged≥50 years with either a maximal carotid artery intima-media thickness of ≥1.1 mm, or a urinary albumin ≥30 mg/g creatinine or who had at least two of the following, abdominal obesity, low HDL cholesterol, high triglyceride levels, and hypertension, were enrolled at 50 institutions. The patients were evaluated using gated SPECT with the stress-rest protocol and followed up for 3 years.

RESULTS

During the follow-up period, 62 (13%) events occurred, including 5 cardiac deaths and 57 cardiovascular events. Patients with summed stress scores (SSS) of ≥9 had a significantly higher incidence (of either death or cardiovascular events) than those with SSS scores of <9 (23 vs. 12%; P=0.009). Multivariate Cox regression analysis showed that significant variables were SSS≥9, a low estimated glomerular filtration rate, and being a current smoker. Univariate Cox regression analysis showed that ticlopidine and insulin use are potent medical modulators of cardiovascular events.

CONCLUSIONS

The incidences of cardiovascular events and death were significantly high in a select population of type 2 diabetic patients with SPECT abnormalities. A targeted treatment strategy is required for asymptomatic but potentially high-risk patients with type 2 diabetes.

Testing of low-risk patients presenting to the emergency department with chest pain: a scientific statement from the American Heart Association

The management of low-risk patients presenting to emergency departments is a common and challenging clinical problem entailing 8 million emergency department visits annually. Although a majority of these patients do not have a life-threatening condition, the clinician must distinguish between those who require urgent treatment of a serious problem and those with more benign entities who do not require admission. Inadvertent discharge of patients with acute coronary syndrome from the emergency department is associated with increased mortality and liability, whereas inappropriate admission of patients without serious disease is neither indicated nor cost-effective. Clinical judgment and basic clinical tools (history, physical examination, and electrocardiogram) remain primary in meeting this challenge and affording early identification of low-risk patients with chest pain. Additionally, established and newer diagnostic methods have extended clinicians' diagnostic capacity in this setting. Low-risk patients presenting with chest pain are increasingly managed in chest pain units in which accelerated diagnostic protocols are performed, comprising serial electrocardiograms and cardiac injury markers to exclude acute coronary syndrome. Patients with negative findings usually complete the accelerated diagnostic protocol with a confirmatory test to exclude ischemia. This is typically an exercise treadmill test or a cardiac imaging study if the exercise treadmill test is not applicable. Rest myocardial perfusion imaging has assumed an important role in this setting. Computed tomography coronary angiography has also shown promise in this setting. A negative accelerated diagnostic protocol evaluation allows discharge, whereas patients with positive findings are admitted. This approach has been found to be safe, accurate, and cost-effective in low-risk patients presenting with chest pain.

Quantitative upright-supine high-speed SPECT myocardial perfusion imaging for detection of coronary artery disease: correlation with invasive coronary angiography

A recently developed camera system for high-speed SPECT (HS-SPECT) myocardial perfusion imaging shows excellent correlation with conventional SPECT. Our goal was to test the diagnostic accuracy of an automated quantification of combined upright and supine myocardial SPECT for detection of coronary artery disease (CAD) (≥ 70% luminal diameter stenosis or, in left main coronary artery, ≥ 50% luminal diameter stenosis) in comparison to invasive coronary angiography (ICA).

METHODS

We studied 142 patients undergoing upright and supine HS-SPECT, including 56 consecutive patients (63% men; mean age ± SD, 64 ± 13 y; 45% exercise stress) without known CAD who underwent diagnostic ICA within 6 mo of HS-SPECT and 86 consecutive patients with a low likelihood of CAD. Reference limits for upright and supine HS-SPECT were created from studies of patients with a low likelihood of CAD. Automated software adopted from supine-prone analysis was used to quantify the severity and extent of perfusion abnormality and was expressed as total perfusion deficit (TPD). TPD was obtained for upright (U-TPD), supine (S-TPD), and combined upright-supine acquisitions (C-TPD). Stress U-TPD ≥ 5%, S-TPD ≥ 5%, and C-TPD ≥ 3% myocardium were considered abnormal for per-patient analysis, and U-TPD, S-TPD, and C-TPD ≥ 2% in each coronary artery territory were considered abnormal for per-vessel analysis.

RESULTS

On a per-patient basis, the sensitivity was 91%, 88%, and 94% for U-TPD, S-TPD, and C-TPD, respectively, and specificity was 59%, 73%, and 86% for U-TPD, S-TPD, and C-TPD, respectively. C-TPD had a larger area under the receiver-operating-characteristic curve than U-TPD or S-TPD for identification of stenosis ≥ 70% (0.94 vs. 0.88 and 0.89, P < 0.05 and not significant, respectively). On a per-vessel basis, the sensitivity was 67%, 66%, and 69% for U-TPD, S-TPD, and C-TPD, respectively, and specificity was 91%, 94%, and 97% for U-TPD, S-TPD, and C-TPD, respectively (P = 0.02 for specificity U-TPD vs. C-TPD).

CONCLUSION

In this first comparison of HS-SPECT with ICA, new automated quantification of combined upright and supine HS-SPECT shows high diagnostic accuracy for detecting clinically significant CAD, with findings comparable to those reported using conventional SPECT.

Identification of myocardial damage in systemic sclerosis: a nuclear cardiology approach

Myocardial involvement is an important prognostic factor in patients with systemic sclerosis, and early diagnosis and staging of the disease have been sought after. Since myocardial damage is characterized by connective tissue disease, including fibrosis and diffuse vascular lesions or microcirculation, nuclear myocardial perfusion imaging has been a promising option for evaluating myocardial damages in early stages. In addition to the conventional stress-rest perfusion imaging, the current use of quantitative electrocardiographic gated imaging has contributed to more precise evaluation of cardiac perfusion, ventricular wall motion, and diastolic function, all of which have enhanced diagnostic ability of evaluating myocardial dysfunction. Abnormal sympathetic imaging with Iodine-123 metaiodobenzylguanidine might be another option for identifying myocardial damage. This paper deals with approaches from nuclear cardiology to detect perfusion and functional abnormality as an early sign of myocardial involvement as well as possible prognostic values in patients with abnormal imaging results. The role of nuclear cardiology in the era of multiple imaging modalities is discussed.

Regional myocardial blood flow measured by stress multidetector computed tomography as a predictor of recovery of left ventricular function after coronary artery bypass grafting

BACKGROUND

Multidetector-row computed tomography (MDCT) applications have expanded to evaluation of myocardial blood flow (MBF) and viability. We quantified regional MBF pre- and post-coronary artery bypass grafting (CABG) using adenosine stress and cardiac 64-MDCT, and investigated whether the results predict MBF and left ventricular (LV) function recovery after CABG.

METHODS

We studied 321 regions in 19 CABG patients who underwent adenosine stress 64-row MDCT perfusion imaging and cine magnetic resonance imaging pre- and post-CABG. Myocardial blood flow was estimated from linear regression equation slopes using Patlak plot analyses and compared with LV function by measuring wall thickening (%WT) using cine magnetic resonance imaging.

RESULTS

Overall mean MBFs were 1.39 +/- 0.49 and 1.95 +/- 0.49 mL/(g min) pre- and post-CABG (P < .0001). Myocardial blood flow in revascularized areas increased significantly (pre-CABG 1.18 +/- 0.45, post-CABG 1.99 +/- 0.66 mL/[g min], P < .001), whereas nonischemic areas showed no difference (1.79 +/- 0.70 and 1.97 +/- 0.46 mL/[g min], P = .14). Revascularized areas with preoperative MBF > or = 0.9 mL/(g min) showed significantly greater MBF improvement than those with preoperative MBF <0.9 mL/(g min) (P = .04). In patients with preoperative LV dysfunction (ejection fraction <40%), %WT in revascularized areas with pre-CABG MBF > or = 0.9 mL/(g min) improved significantly after CABG (pre-%WT 40.9 +/- 22.9, post-%WT 52.8 +/- 20.6, P = .03) versus those with pre-CABG MBF <0.9 mL/(g min) (pre-%WT 53.2 +/- 35.5, post-%WT 42.5 +/- 17.0, P = .40).

CONCLUSIONS

Our results demonstrated more significantly increased MBF post-CABG than pre-CABG, particularly in revascularized areas. Regional MBF before CABG may predict MBF and LV function recovery, in the short term, after CABG.

Recent advances in the management of chronic stable angina I: approach to the patient, diagnosis, pathophysiology, risk stratification, and gender disparities

The potential importance of both prevention and personal responsibility in controlling heart disease, the leading cause of death in the USA and elsewhere, has attracted renewed attention. Coronary artery disease is preventable, using relatively simple and inexpensive lifestyle changes. The inexorable rise in the prevalence of obesity, diabetes, dyslipidemia, and hypertension, often in the risk cluster known as the metabolic syndrome, drives the ever-increasing incidence of heart disease. Population-wide improvements in personal health habits appear to be a fundamental, evidence based public health measure, yet numerous barriers prevent implementation. A common symptom in patients with coronary artery disease, classical angina refers to the typical chest pressure or discomfort that results when myocardial oxygen demand rises and coronary blood flow is reduced by fixed, atherosclerotic, obstructive lesions. Different forms of angina and diagnosis, with a short description of the significance of pain and silent ischemia, are discussed in this review. The well accepted concept of myocardial oxygen imbalance in the genesis of angina is presented with new data about clinical pathology of stable angina and acute coronary syndromes. The roles of stress electrocardiography and stress myocardial perfusion scintigraphic imaging are reviewed, along with the information these tests provide about risk and prognosis. Finally, the current status of gender disparities in heart disease is summarized. Enhanced risk stratification and identification of patients in whom procedures will meaningfully change management is an ongoing quest. Current guidelines emphasize efficient triage of patients with suspected coronary artery disease. Many experts believe the predictive value of current decision protocols for coronary artery disease still needs improvement in order to optimize outcomes, yet avoid unnecessary coronary angiograms and radiation exposure. Coronary angiography remains the gold standard in the diagnosis of coronary artery obstructive disease. Part II of this two part series will address anti-ischemic therapies, new agents, cardiovascular risk reduction, options to treat refractory angina, and revascularization.

Functional assessment of coronary artery flow using adenosine stress dual-energy CT: a preliminary study

We attempted to assess coronary artery flow using adenosine-stress and dual-energy mode with dual-source CT (DE-CT). Data of 18 patients with suspected coronary arteries disease who had undergone cardiac DE-CT were retrospectively analyzed. The patients were divided into two groups: 10 patients who performed adenosine stress CT, and 8 patients who performed rest CT as controls. We reconstructed an iodine map and composite images at 120 kV (120 kV images) using raw data with scan parameters of 100 and 140 kV. We measured mean attenuation in the coronary artery proximal to the distal portion on both the iodine map and 120 kV images. Coronary enhancement ratio (CER) was calculated by dividing mean attenuation in the coronary artery by attenuation in the aortic root, and was used as an estimate of coronary enhancement. Coronary stenosis was identified as a reduction in diameter of >50% on CT angiogram, and myocardial ischemia was diagnosed by adenosine-stress myocardial perfusion scintigraphy. The iodine map showed that CER was significantly lower for ischemic territories (0.76 ± 0.06) or stenosed coronary arteries (0.77 ± 0.06) than for non-ischemic territories (0.95 ± 0.21, P = 0.02) or non-stenosed coronary arteries (1.07 ± 0.33, P < 0.001). The 120 kV images showed no difference in CER between these two groups. Use of CER on the iodine map separated ischemic territories from non-ischemic territories with a sensitivity of 86% and a specificity of 75%. Our quantification is the first non-invasive analytical technique for assessment of coronary artery flow using cardiac CT. CER on the iodine map is a candidate method for demonstration of alteration in coronary artery flow under adenosine stress, which is related to the physiological significance of coronary artery disease.

Detection of myocardial perfusion abnormalities: standard dual-source coronary computed tomography angiography versus rest/stress technetium-99m single-photo emission CT

We compared coronary dual-source computed tomography angiography (corDSCTA) with technetium-99m single-photon emission computed tomography (SPECT) for the detection of myocardial perfusion abnormalities. Fifty-five consecutive patients underwent both gated myocardial perfusion SPECT and corDSCTA, the latter during a single arterial-phase injection of contrast agent. The perfusion defects visualised by corDSCTA correlated with the findings of rest/stress SPECT. Abnormal findings on stress SPECT, which were due to either ischaemia or infarct, were found in 24 patients. In comparison to SPECT at rest, corDSCTA detected perfusion defects with a sensitivity and specificity of 100% and 78%, respectively. Compared to SPECT at stress, the sensitivity and specificity values of corDSCTA were 83.3% and 90.3%, respectively. On corDSCTA , the average attenuation values of perfusion defects that corresponded to chronic infarcts (-8.5+/-22.2 HU) were significantly lower (p = 0.002) than those of non-infarct-related perfusion defects (43.1+/-17.5 HU). Using rest/stress SPECT is the gold standard for the diagnosis of myocardial ischaemia, corDSCTA was able to diagnose ischaemic disease (defined as the presence of high-grade stenotic CAD (>or=50% luminal narrowing)) with a sensitivity and specificity of 59% and 89%, respectively, in patients with no known history of myocardial infarction (n = 4). Thus, corDSCTA may serve as a diagnostic tool for the detection of perfusion abnormalities (first) visualised by SPECT. There appears to be a limited correlation between coronary stenotic disease and SPECT findings.

Influence of extracardiac activity and perfusion abnormalities on myocardial perfusion gated SPECT parameters: interobserver analysis

OBJECTIVE

Extracardiac activity (ECA) may affect interpretation of gated SPECT myocardial perfusion studies (MPSs). To solve this problem, available softwares include myocardial edge delimitation.

PURPOSE

To evaluate the influence of ECA in automatic myocardial edge detection under normal conditions and with abnormal perfusion and also evaluate the reproducibility of semi-automatic processing.

METHODS

A total of 100 MPSs, 50 with ECA, were analyzed. Each subgroup included 25 cases with perfusion abnormalities. The cases were processed automatically and by 4 independent operators with different levels of experience. Commercial QGS and QPS softwares were used with tools to mask and relocate the left ventricle area. Functional parameters (final diastolic and systolic volumes and ejection fraction) and perfusion parameters such as the reversibility perfusion score and rest perfusion defect extension were analyzed. The data were compared with Pearson's correlation and Student's test.

RESULTS

Interobserver correlation significantly worsened with the presence of ECA and was moderately affected by perfusion abnormalities. More experienced observers presented better correlation. Reproducibility was greater for the functional perfusion parameters, independently of the observer's experience.

CONCLUSIONS

ECA significantly affects automatic edging delimitation, affecting the MPS values. Interobserver reproducibility with manual processing was more altered regarding functional parameters than in the perfusion scores. Perfusion abnormalities did not interfere with software reproducibility, and when present, better correlation was found. If ECA is not present, manual intervention should be avoided.

Comparison of high risk stress myocardial perfusion imaging findings in men with rapid versus prolonged recovery of ST-segment depression after exercise stress testing

ST-segment depression during stress testing predicts future risk for adverse cardiovascular events and routinely prompts further noninvasive imaging or invasive evaluation for coronary artery disease (CAD). A subset of patients develop ST depression at peak exercise that rapidly resolves early in the recovery period (ST-rapid). The goal of this study was to compare the prevalence of single-photon emission computed tomographic myocardial perfusion imaging (MPI) findings in patients with ST-rapid to those with prolonged ST depression (ST-prolonged) and those without ST depression (ST-normal). A total of 637 men without previous CAD and with interpretable rest electrocardiograms referred for exercise stress MPI were included in this study. ST depression was defined as > or =1-mm ST depression occurring 80 ms after the J point at peak exercise. ST-rapid was defined as ST depression with recovery of the ST depression by 1 minute into recovery. Men with ST-rapid were younger (55.4 +/- 7.6 vs 62.6 +/- 9.6 years, p <0.001) and had better exercise capacity (11.2 +/- 2.8 vs 9.4 +/- 3.0 METs, p <0.001) than men with ST-prolonged. Compared to ST-prolonged, ST-rapid was associated with significantly less mild CAD (summed stress score > or =4; 27% vs 47%, p = 0.02), severe CAD (summed stress score >8; 9% vs 29%, p = 0.004), and a composite of high-risk MPI findings (summed stress score >8 or ejection fraction <40%; 11% vs 32%, p = 0.003). There were no significant differences in exercise capacity, the presence of CAD, or the composite of high-risk MPI findings between men with ST-rapid and those with ST-normal. In conclusion, men who developed ST-rapid during exercise stress testing had markedly fewer abnormal and high-risk MPI findings compared to those with prolonged ST depression. In fact, the prevalence of MPI abnormalities in men with ST-rapid was similar to that in men with normal electrocardiographic responses to exercise.

Chest pain in focal musculoskeletal disorders

The musculoskeletal system is a recognized source of chest pain. However, despite the apparently benign origin, patients with musculoskeletal chest pain remain under-diagnosed, untreated, and potentially continuously disabled in terms of anxiety, depression, and activities of daily living. Several overlapping conditions and syndromes of focal disorders, including Tietze syndrome, costochondritis, chest wall syndrome, muscle tenderness, slipping rib, cervical angina, and segmental dysfunction of the cervical and thoracic spine, have been reported to cause pain. For most of these syndromes, evidence arises mainly from case stories and empiric knowledge. For segmental dysfunction, clinical features of musculoskeletal chest pain have been characterized in a few clinical trials. This article summarizes the most commonly encountered syndromes of focal musculoskeletal disorders in clinical practice.

Computed tomographic coronary artery calcium assessment for evaluating chest pain in the emergency department: long-term outcome of a prospective blind study

OBJECTIVE

To determine the long-term outcome of computed tomographic (CT) quantification of coronary artery calcium (CAC) used as a triage tool for patients presenting with chest pain to an emergency department (ED).

PATIENTS AND METHODS

Patients (men aged 30-62 years and women aged 30-65 years) with chest pain and low-to-moderate probability of coronary artery disease underwent both conventional ED chest pain evaluation and CT CAC assessment prospectively. Patients' physicians were blinded to the CAC results. The results of the conventional evaluation were compared with CAC findings on CT, and the long-term outcome in patients undergoing CT CAC assessment was established. Primary end points (acute coronary syndrome, death, fatal or nonfatal non-ST-segment elevation myocardial infarction, fatal or nonfatal ST-segment elevation myocardial infarction) and secondary outcomes (coronary artery bypass grafting, percutaneous transluminal coronary angioplasty, coronary stenting, or a combination thereof) were obtained when the patient was dismissed from the ED or hospital and then at 30 days, 1 year, and 5 years.

RESULTS

Of the 263 study patients, 133 (51%) had a CAC score of zero. This absence of CAC correlated strongly with the likelihood of noncardiac chest pain. Among 133 patients with a CAC score of zero, only 1 (<1%) had cardiac chest pain. Conversely, of the 31 patients shown to have cardiac chest pain, 30 (97%) had evidence of CAC on CT. When a CAC cutoff score of 36 was used, as suggested by receiver operating characteristic analysis, sensitivity was 90%; specificity, 85%; positive predictive value, 44%; and negative predictive value, 99%. During long-term follow-up, patients without CAC experienced no cardiac events at 30 days, 1 year, and 5 years.

CONCLUSION

Findings suggest that CT CAC assessment is a powerful adjunct in chest pain evaluation for the population at low-to-intermediate risk. Absent or minimal CAC in this population makes cardiac chest pain extremely unlikely. The absence of CAC suggests an excellent long-term (5-year) prognosis, with no primary or secondary cardiac outcomes occurring in study patients at 5-year follow-up.

Technetium-99m-sestamibi redistribution after exercise stress test identified by a novel cardiac gamma camera: two case reports

Single photon emission computer tomography (SPECT) myocardial perfusion imaging (MPI) employing technetium-99m (Tc-99m)-based imaging tracers is the mainstay of nuclear cardiology for the detection of myocardial ischemia. Current guidelines for same day rest/stress Tc-99m-sestamibi SPECT MPI recommend image acquisition 15-60 minutes after the stress testing. A novel sensitive SPECT imaging technique, D-SPECT, allows fast acquisition of images and captures rapid changes in radiotracer distribution. Here we report 2 cases of SPECT MPI in patients with angiographically confirmed coronary artery disease (CAD) where Tc-99m-sestamibi exhibited marked redistribution between early (6-8 min) and late (60-70 min) post-stress imaging leading to an underestimation of the extent and severity of ischemia on late images. These observations suggest that early imaging maybe more sensitive for CAD detection. Fast SPECT imaging techniques, such as D-SPECT, will facilitate similar studies in the future as they will allow fast image acquisition at several time points after the stress test.

Identification of asymptomatic type 2 diabetes mellitus patients with a low, intermediate and high risk of ischaemic heart disease: is there an algorithm?

AIMS/HYPOTHESIS

The leading cause of death in type 2 diabetes is cardiovascular disease (CVD). We examined the prevalence of myocardial ischaemia in type 2 diabetes patients and tried to establish an algorithm to identify patients with a high risk of ischaemic heart disease.

METHODS

Type 2 diabetes patients who had no known or suspected CVD, and had been referred consecutively to a diabetes clinic for the first time (n=305; age 58.6+/-11.3 years; diabetes duration 4.5+/-5.3 years) were screened for myocardial ischaemia using myocardial perfusion scintigraphy (MPS).

RESULTS

The univariate predictors of myocardial ischaemia were: atypical or typical angina pectoris, two or more traditional risk factors for CVD, BMI >32 kg/m2, systolic blood pressure >140 mmHg, HbA1c >8.5%, high-sensitivity C-reactive protein >4.0 mg/l, N-terminal pro-brain natriuretic peptide >300 pg/ml, left atrial volume index >32 ml/m2, left ventricular ejection fraction <50%, and carotid and peripheral arterial disease. The algorithm identified low (n=96), intermediate (n=65) and high risk groups (n=115), in which the prevalence of myocardial ischaemia was 15%,23% and 43%, respectively. Overall the algorithm reduced the number of patients referred to MPS from 305 to 144.However, the sensitivity and specificity of the algorithm was just 68% and 62%, respectively.

CONCLUSIONS/INTERPRETATION

Our algorithm was able to stratify which patients had a low, intermediate or high risk of myocardial ischaemia based on MPS. However, the algorithm had low sensitivity and specificity, combined with high cost and time requirements.

TRIAL REGISTRATION

clinicaltrials.gov NCT00298844 FUNDING: The study was funded by the Danish Cardio vascular Research Academy (DaCRA), The Danish Diabetes Association and The Danish Heart Foundation.