Coronary multidetector computed tomography in the assessment of patients with acute chest pain

Emergency cardiac CT for suspected acute coronary syndrome: qualitative and quantitative assessment of coronary, pulmonary, and aortic image quality

OBJECTIVE

The purpose of this study was to determine whether a dedicated coronary CT protocol provides adequate contrast enhancement and artifact-free depiction of coronary, pulmonary, and aortic circulation.

MATERIALS AND METHODS

Dedicated coronary 64-MDCT data sets of 50 patients (27 men; mean age, 54 +/- 12.4 years) consecutively admitted from the emergency department with suspected acute coronary syndrome were analyzed. Two independent observers graded overall coronary arterial image quality and qualitative and quantitative contrast opacification, motion, and streak artifacts within the pulmonary arteries and aorta.

RESULTS

Coronary image quality was excellent in 48 patients (96%) and moderate in two patients (4%). Eleven left main and 22 left upper lobar pulmonary arteries were not visualized. Qualitative evaluation showed pulmonary arterial tree opacification to be excellent except for the right and left lower lateral and posterior segmental branches (52-54% rate of poor opacification). Quantitative evaluation showed four central (8%), six lobar (8%), and 206 segmental (29%) branches had poor contrast opacification (< 200 HU). Nineteen right upper lobar arteries (38%) were slightly and one was severely affected by streak artifact. At the segmental pulmonary artery level, marked differences in contrast enhancement were detected between the upper (292 +/- 72 HU) and both the middle (249 +/- 85 HU) and the lower lobes (248 +/- 76 HU) (p < 0.01). Mean aortic opacification was 300 +/- 34 HU with excellent contrast homogeneity without severe motion or streak artifacts.

CONCLUSION

In the evaluation of patients presenting to the emergency department with suspected acute coronary syndrome, a dedicated coronary CT protocol enables excellent assessment of the coronary arteries and proximal ascending aorta but does not depict the pulmonary vasculature well enough for exclusion of pulmonary embolism.

Cardiovascular risk in women with non-specific chest pain (from the Women's Health Initiative Hormone Trials)

Women discharged with diagnoses of nonspecific chest pain (NSCP) may be at increased risk for subsequent coronary artery disease (CAD) events. The influence of hormone therapy on NSCP is unknown. The Women's Health Initiative (WHI) enrolled postmenopausal women aged 50 to 79 years. The duration of follow-up was 7.1 years in the WHI Estrogen-Alone trial (E-Alone) and 5.6 years in the WHI Estrogen Plus Progestin trial (E+P). After excluding women with previous cardiovascular disease, 9,427 women in E-Alone and 15,105 women in E+P were included in this analysis. NSCP, defined as having a primary hospital discharge diagnosis of NSCP by International Classification of Diseases, Ninth Revision, code, was reported in 322 women in E-Alone and 249 in E+P. Risks for subsequent CAD events were estimated using intent-to-treat Cox proportional-hazards models stratified by clinic and adjusted for age and other risk factors. In the fully adjusted models of the combined trials, women with NSCP had a twofold greater risk for subsequent nonfatal CAD events, including nonfatal myocardial infarction (2.3% vs 1.7%, hazard ratio [HR] 2.10, 95% confidence interval [CI] 1.11 to 3.98), revascularization (3.5% vs 2.6%, HR 1.99, 95% CI 1.20 to 3.30), and hospitalized angina (3.7% vs 2.3%, HR 2.39, 95% CI 1.46 to 3.92). Hormone therapy did not appear to have a significant effect on either the incidence of NSCP hospitalizations (E-Alone: HR 1.04, 95% CI 0.81 to 1.32; E+P: HR 0.78, 95% CI 0.59 to 1.02) or the risk for a subsequent CAD event. In conclusion, a hospitalization for NSCP doubles the risk for a subsequent CAD event in postmenopausal women over the next 5 to 7 years and identifies them as candidates for aggressive risk factor treatment.

The triple work-up for emergency department patients with acute chest pain: how often does it occur?

OBJECTIVES

To measure the degree of overlap and diagnostic yield for evaluations of acute coronary syndrome (ACS), pulmonary embolism (PE), and aortic dissection (AD) among Emergency Department (ED) patients.

METHODS

We conducted a cross-sectional descriptive study of consecutive adult patients seen in the ED of a 78,000-annual-visit urban academic medical center. Patients who had received at least one of eight of the tests used in our ED to diagnose these three diseases were identified through three methods, and a final study population list was created. Overlap of evaluations and diagnostic yields were calculated by simple descriptive statistics.

RESULTS

Over a 2-week period, 626 patient encounters among 622 unique patients were identified. Among these 626 visits, 139 (22%) included diagnostic tests for more than one of the three diagnoses of interest. The majority of these multiple tests were for ACS plus PE (n = 121, 87% of all multiple tests), whereas a minority of patients received tests for ACS plus AD (n = 14, 10% of all multiple tests) or for the "triple work-up" of ACS plus PE plus AD (n = 4, 2.9% of all multiple tests).

CONCLUSION

Although the "triple work-up" evaluation for ACS, PE, and AD is relatively uncommon, a significant number of ED patients who are evaluated for at least one of these three major chest pain syndromes receive simultaneous testing for one of the others.

Noninvasive evaluation with multislice computed tomography in suspected acute coronary syndrome: plaque morphology on multislice computed tomography versus coronary calcium score

OBJECTIVES

Our aim was to evaluate the atherosclerotic plaque burden and morphology as determined by 64-slice multislice computed tomography (MSCT) coronary angiography in relation to the calcium score in patients presenting with suspected acute coronary syndrome (ACS).

BACKGROUND

The absence of coronary calcium during coronary calcium scoring has been proposed to rule out significant coronary artery disease (CAD). However, data in patients presenting with suspected ACS are scarce.

METHODS

In 40 patients (age 57 +/- 11 years, 26 men) presenting with suspected ACS, MSCT coronary angiography in combination with coronary calcium scoring was performed before conventional coronary angiography. MSCT angiograms were evaluated for the presence or absence of coronary atherosclerotic plaque and the presence or absence of obstructive (> or =50% luminal narrowing) CAD. In addition, plaque type was determined, and findings were related to the calcium score.

RESULTS

Coronary artery disease was observed in 38 patients, of whom 10 patients had nonobstructive and 28 patients had obstructive CAD, confirmed by conventional coronary angiography in all patients. In patients with CAD, plaques were distributed as follows: 39% noncalcified plaques, 47% mixed plaques, and 14% calcified plaques. Coronary calcium was detected in 27 patients, of whom 10 had a score >400. In 13 (33%) patients, no coronary calcium was observed, but in 11 (85%), atherosclerotic plaques were detected on MSCT angiography.

CONCLUSIONS

In patients presenting with suspected ACS, noncalcified plaques are highly prevalent and the absence of coronary calcium does not reliably exclude the presence of (significant) atherosclerosis. This information may be of value to improve our understanding of the potential role of MSCT in this patient population.

Diagnostic uncertainty and costs associated with current emergency department evaluation of low risk chest pain

INTRODUCTION

Of all stress tests done in low risk Emergency Department observation units (OU), a small, but significant number may be reported as positive or indeterminate. The objective of this study is to quantify the prevalence and costs associated with positive and indeterminate stress tests that result in negative cardiac catheterization.

METHODS

Retrospective observational cohort study over 9 months. All patients undergoing the chest pain protocol who got cardiac stress testing in the OU were eligible for inclusion. Cost data were derived from an institutional activity-based cost system utilizing actual costs. Chart review was completed on all patients with positive and indeterminate stress tests and a randomly chosen sample of those with negative stress tests.

RESULTS

Of the 1194 patients who met the inclusion criteria, 1084 (90.8%) had a negative stress test. Sixty-two (5.2%) had a positive stress test, and 48 (4.0%) had an indeterminate stress test. Of all 59 patients who underwent catheterization, 41 (69.5%) were negative cardiac catheterizations. The prevalence among all OU stress test patients of positive or indeterminate stress tests with subsequent negative cardiac catheterization was 41/1194 (3.4%; 95% CI 2.5%-4.6%). The prevalence of significant coronary artery disease at cardiac catheterization was 18/1194 (1.5%; 95% CI 1.0%-2.4%). Patients with a positive or indeterminate stress test who had a negative catheterization incurred increased OU costs ($1385 vs. $1,039, P = 0.012), total costs ($7298 vs. $1562, P < 0.001) and length of inpatient stay (1.83 days vs. 0.00 days) when compared with those who had a negative stress test.

CONCLUSION

The probability of going to the OU and having a positive or indeterminate stress test resulting in a subsequent negative catheterization was double the probability of having a stress test result in catheterization that detected significant coronary artery disease. These patients incurred 5 times the total cost when compared with those patients with negative stress testing. Further investigation is warranted to determine alternative risk stratification methods for these low risk chest pain patients with positive stress tests.

Volumetric measurement of pericardial adipose tissue from contrast-enhanced coronary computed tomography angiography: a reproducibility study

PURPOSE

Pericardial adipose tissue may exert unique metabolic and cardiovascular risks in patients. The use of cardiac multidetector computed tomography (MDCT) imaging may enable the accurate localization and quantification of pericardial and intrathoracic adipose tissue. The reproducibility of electrocardiogram-gated high-resolution cardiac MDCT-based volumetric quantification of pericardial and intrathoracic adipose tissue has not been reported.

METHODS

We included 100 consecutive patients (age 54.5 +/- 12.0 yr, 60% men) who underwent a standard contrast-enhanced coronary CT for the evaluation of coronary artery plaque and stenosis (64-slice MDCT, temporal resolution: 210 ms, spatial resolution: 0.6 mm, 850 mAs, 120, kvp) after a presentation of acute chest pain. Two independent observers measured intrathoracic (IAT) and pericardial adipose tissue (PAT) by using a semiautomatic segmentation algorithm based on three-dimensional analysis.

RESULTS

Inter-reader reproducibility was excellent (relative difference: 7.35 +/- 7.22% for PAT and 6.23 +/- 4.91% for IAT, intraclass correlation 0.98 each). Similar results were obtained for intra-observer reproducibility (relative difference: 5.18 +/- 5.19% for PAT and 4.34 +/- 4.12% for IAT, intraclass correlation 0.99 each).

CONCLUSION

This study demonstrates that MDCT-based 3D semiautomatic segmentation for volumetric quantification of PAT and IAT is highly reproducible. Further research is warranted to assess whether volumetric measurements may substantially improve the predictive value of obesity measures for insulin resistance, type 2 diabetes mellitus, and cardiovascular diseases.

Structural alterations of the coronary arterial wall are associated with myocardial flow heterogeneity in type 2 diabetes mellitus

PURPOSE

To determine the relationship between carotid intima-media thickness (IMT), coronary artery calcification (CAC), and myocardial blood flow (MBF) at rest and during vasomotor stress in type 2 diabetes mellitus (DM).

METHODS

In 68 individuals, carotid IMT was measured using high-resolution vascular ultrasound, while the presence of CAC was determined with electron beam tomography (EBT). Global and regional MBF was determined in milliliters per gram per minute with (13)N-ammonia and positron emission tomography (PET) at rest, during cold pressor testing (CPT), and during adenosine (ADO) stimulation.

RESULTS

There was neither a relationship between carotid IMT and CAC (r = 0.10, p = 0.32) nor between carotid IMT and coronary circulatory function in response to CPT and during ADO (r = -0.18, p = 0.25 and r = 0.10, p = 0.54, respectively). In 33 individuals, EBT detected CAC with a mean Agatston-derived calcium score of 44 +/- 18. There was a significant difference in regional MBFs between territories with and without CAC at rest and during ADO-stimulated hyperemia (0.69 +/- 0.24 vs. 0.74 +/- 0.23 and 1.82 +/- 0.50 vs. 1.95 +/- 0.51 ml/g/min; p < or = 0.05, respectively) and also during CPT in DM but less pronounced (0.81 +/- 0.24 vs. 0.83 +/- 0.23 ml/g/min; p = ns). The increase in CAC was paralleled with a progressive regional decrease in resting as well as in CPT- and ADO-related MBFs (r = -0.36, p < or = 0.014; r = -0.46, p < or = 0.007; and r = -0.33, p < or = 0.041, respectively).

CONCLUSIONS

The absence of any correlation between carotid IMT and coronary circulatory function in type 2 DM suggests different features and stages of early atherosclerosis in the peripheral and coronary circulation. PET-measured MBF heterogeneity at rest and during vasomotor stress may reflect downstream fluid dynamic effects of coronary artery disease (CAD)-related early structural alterations of the arterial wall.

Comparison of 64-slice multi-detector computed tomography coronary angiography between asymptomatic, type 2 diabetes mellitus and impaired glucose tolerance patients

BACKGROUND

Cardiovascular disease is the most frequent cause of death and disability for diabetic patients, and patients with diabetes are more likely to have silent ischemia. Multi-detector computed tomography (MDCT) allows non-invasive assessment of coronary artery stenosis and plaque properties. In this study, we investigated whether 64-slice MDCT can non-invasively identify significant coronary artery stenosis in asymptomatic, type 2 diabetes mellitus (T2DM) and impaired glucose tolerance (IGT) patients.

METHODS AND RESULTS

The study population consisted of 154 consecutive asymptomatic patients [IGT (n=93), T2DM (n=61)]. All patients underwent contrast-enhanced 64-slice MDCT. The number of diseased coronary segments was classified as showing obstructive (> or = 50% luminal narrowing) disease or not. Significant coronary stenosis was detected in 43 (27.9%) of 154 enrolled patients. Patients with T2DM showed significantly more coronary stenosis than patients with IGT (41% vs. 19.4%; p<0.01). Twenty-three patients [14.9%; IGT (n=9), T2DM (n=14)] underwent percutaneous coronary intervention (PCI) for severe stenosis. Patients with T2DM showed significantly more calcified plaque than IGT (47.5% vs. 29%; p<0.05), but not significantly more soft plaque (19.7% vs. 15.1%; ns), or significantly different remodeling index (1.05+/-0.18 vs. 1.04+/-0.21; ns), respectively.

CONCLUSIONS

64-Slice MDCT can non-invasively identify significant coronary artery stenosis in asymptomatic, T2DM and IGT patients.

Evaluation of a "triple rule-out" coronary CT angiography protocol: use of 64-Section CT in low-to-moderate risk emergency department patients suspected of having acute coronary syndrome

PURPOSE

To determine whether coronary computed tomographic (CT) angiography "triple rule-out" evaluation of emergency department (ED) patients presenting with symptoms suggestive of acute coronary syndrome (ACS) can help identify a subset of patients who can be discharged without adverse clinical outcomes within 30 days.

MATERIALS AND METHODS

This protocol was approved by the university institutional review board. Each patient provided written informed consent prior to inclusion. Coronary CT angiography was performed in 201 consecutive low-to-moderate risk ACS patients. A triple rule-out protocol was used to evaluate for coronary disease, pulmonary embolism, aortic dissection, and other thoracic disease. Four patients were excluded because of technical problems. The remaining subjects underwent a 30-day follow-up.

RESULTS

A disease process other than coronary atherosclerosis that explained the presenting symptoms was diagnosed in 22 (11%) of 197 patients. Clinically important noncoronary diagnoses that did not explain patient symptoms were identified in 27 (14%) of 197 additional patients. With respect to coronary artery disease, 10 patients had severe disease (>70% stenosis), 12 had moderate disease (50%-70% stenosis), 46 had mild disease (up to 50% stenosis), and 129 had no disease. No further diagnostic testing was performed in 133 (76%) of 175 of patients with no to mild coronary disease. At 30-day follow-up, the negative predictive value of coronary CT angiography with no more than mild disease was 99.4%. There were no adverse outcomes at 30 days.

CONCLUSION

Triple rule-out coronary CT angiography evaluation of low-to-moderate risk ACS patients presenting to the ED provided a noncoronary diagnosis that explained the presenting complaint in 11% of patients, suggested the presence of significant moderate-to-severe coronary disease in 11% (22 of 197) of patients, and precluded additional diagnostic cardiac testing in the majority of patients with no adverse outcomes at 30-day follow-up.

Cardiac magnetic resonance with T2-weighted imaging improves detection of patients with acute coronary syndrome in the emergency department

BACKGROUND

Cardiac magnetic resonance (CMR) imaging permits early triage of patients presenting to the emergency department with acute chest pain but has been limited by the inability to differentiate new from old myocardial infarction. Our objective was to evaluate a CMR protocol that includes T2-weighted imaging and assessment of left ventricular wall thickness in detecting patients with acute coronary syndrome in the emergency department.

METHODS AND RESULTS

In this prospective cohort observational study, we enrolled patients presenting to the emergency department with acute chest pain, negative cardiac biomarkers, and no ECG changes indicative of acute ischemia. The CMR protocol consisted of T2-weighted imaging, first-pass perfusion, cine function, delayed-enhancement magnetic resonance imaging, and assessment of left ventricular wall thickness. The clinical outcome (acute coronary syndrome) was defined by review of clinical charts by a consensus panel that used American Heart Association/American College of Cardiology guidelines. Among 62 patients, 13 developed acute coronary syndrome during the index hospitalization. The mean CMR time was 32+/-8 minutes. The new CMR protocol (with the addition of T2-weighted and left ventricular wall thickness) increased the specificity, positive predictive value, and overall accuracy from 84% to 96%, 55% to 85%, and 84% to 93%, respectively, compared with the conventional CMR protocol (cine, perfusion, and delayed-enhancement magnetic resonance imaging). Moreover, in a logistic regression analysis that contained information on clinical risk assessment (c-statistic=0.695) and traditional cardiac risk factors (c-statistic=0.771), the new CMR protocol significantly improved the c-statistic to 0.958 (P<0.0001).

CONCLUSIONS

The present study indicates that a new CMR protocol improves the detection of patients with acute coronary syndrome in the emergency department and adds significant value over clinical assessment and traditional cardiac risk factors.

Usefulness of 64-slice multidetector computed tomography as an initial diagnostic approach in patients with acute chest pain

BACKGROUND

Recently, multidetector computed tomography (MDCT) has been proposed as an accurate diagnostic tool to evaluate for coronary artery disease. However, the role of MDCT as part of the initial diagnostic for evaluating acute chest pain is less well established.

METHODS

We prospectively enrolled patients presenting with acute chest pain to the emergency department (ED) and risk stratified them based on the pretest probability for an acute coronary syndrome (ACS): (1) very low, (2) low, (3) intermediate, (4) high, and (5) very high or definite. After exclusion of very low and very high risk patients, 268 patients were randomized to either immediate 64-slice cardiac MDCT or a conventional diagnostic strategy. Number of admissions, ED and hospital length of stay (LOS), and major adverse cardiac events over 30 days of follow-up were compared between the strategies based on the pretest probability for ACS.

RESULTS

The number of patients ultimately diagnosed with an ACS did not differ between the 2 strategies. Emergency department LOS and total admissions were not different between strategies. Patients in the MDCT-based strategy had a decreased hospital LOS (P = .049) and fewer admissions deemed unnecessary (P = .007). Reductions in unnecessary admissions were more prominent in intermediate-risk patients (P = .015). None of the patients discharged from the ED in the MDCT-based strategy experienced major adverse cardiac events at follow-up.

CONCLUSION

Use of an MDCT-based strategy in the ED as part of the initial diagnostic approach for patients presenting with acute chest pain is safe and efficiently reduces avoidable admissions in patients with an intermediate pretest probability for ACS.

Non-invasive assessment of plaque rupture by 64-slice multidetector computed tomography--comparison with intravascular ultrasound

BACKGROUND

Plaque rupture and secondary thrombus formation play key roles in the onset of acute coronary syndrome (ACS). Multidetector computed tomography (MDCT) allows the non-invasive assessment of coronary artery stenosis and plaque properties. In this study, we investigated whether 64-slice MDCT could non-invasively detect a plaque rupture in patients with de novo angina.

METHODS AND RESULTS

The study population comprised 67 patients with de novo angina. All patients underwent contrast-enhanced 64-slice MDCT and intravascular ultrasound (IVUS). Patients were divided into a plaque rupture group (n=27) and a non-rupture group (n=40) based on the IVUS. The 64-slice MDCT revealed that the prevalence of an ulcer-like enhancement space (37% vs 5%, p<0.01), a ring-like sign (41% vs 18%, p=0.04), in the plaque rupture group was higher than those in the non-rupture group. Maximum plaque thickness (2.1+/-0.9 mm vs 1.6+/-1.0 mm, p=0.04), outer vessel area (17.6+/-4.9 mm2 vs 13.4+/-5.0 mm2, p<0.01), percentage plaque area (82.3+/-9.1% vs 73.4+/-15.7%, p=0.01), and remodeling index (1.11+/-0.18 vs 1.01+/-0.15, p=0.04) of the plaque rupture group were all significantly larger than those of the non-rupture group.

CONCLUSIONS

The 64-slice MDCT can identify differences in lesion morphologies between ruptured plaques and non-ruptured plaques. From our results, the 64-slice MDCT might provide a useful tool for the non-invasive detection of plaque rupture.

Sixty-four-slice computed tomography of the coronary arteries: cost-effectiveness analysis of patients presenting to the emergency department with low-risk chest pain

OBJECTIVES

The aim was to use a computer model to estimate the cost-effectiveness of 64-slice multidetector computed tomography (MDCT) of the coronary arteries in the emergency department (ED) compared to an observation unit (OU) stay plus stress electrocardiogram (ECG) or stress echocardiography for the evaluation of low-risk chest pain patients presenting to the ED.

METHODS

A decision analytic model was developed to compare health outcomes and costs that result from three different risk stratification strategies for low-risk chest pain patients in the ED: stress ECG testing after OU care, stress echocardiography after OU care, and MDCT with no OU care. Three patient populations were modeled with the prevalence of symptomatic coronary artery disease (CAD) being very low risk, 2%; low risk, 6% (base case); and moderate risk, 10%. Outcomes were measured as quality-adjusted life years (QALYs). Incremental cost-effectiveness ratios (ICERs), the ratio of change in costs of one test over another to the change in QALY, were calculated for comparisons between each strategy. Sensitivity analyses were conducted to test the robustness of the results to assumptions regarding the characteristics of the risk stratification strategies, costs, utility weights, and likelihood of events.

RESULTS

In the base case, the mean (+/- standard deviation [SD]) costs and QALYs for each risk stratification strategy were MDCT arm $2,684 (+/- $1,773 to $4,418) and 24.69 (+/- 24.54 to 24.76) QALYs, stress echocardiography arm $3,265 (+/- $2,383 to $4,836) and 24.63 (+/- 24.28 to 24.74) QALYs, and stress ECG arm $3,461 (+/- $2,533 to $4,996) and 24.59 (+/- 24.21 to 24.75) QALYs. The MDCT dominated (less costly and more effective) both OU plus stress echocardiography and OU plus stress ECG. This resulted in an ICER where the MDCT arm dominated the stress echocardiography arm (95% confidence interval [CI] = dominant to $29,738) and where MDCT dominated the ECG arm (95% CI = dominant to $7,332). The MDCT risk stratification arm also dominated stress echocardiography and stress ECG in the 2 and 10% prevalence scenarios, which demonstrated the same ICER trends as the 6% prevalence CAD base case. The thresholds where the MDCT arm remained a cost-saving strategy compared to the other risk stratification strategies were cost of MDCT, < $2,097; cost of OU care, > $1,092; prevalence of CAD, < 70%; MDCT specificity, > 65%; and a MDCT indeterminate rate, < 30%.

CONCLUSIONS

In this computer-based model analysis, the MDCT risk stratification strategy is less costly and more effective than both OU-based stress echocardiography and stress ECG risk stratification strategies in chest pain patients presenting to the ED with low to moderate prevalence of CAD.

Coronary computed tomography angiography---a promising imaging modality in diagnosing coronary artery disease

BACKGROUND

Traditionally, information on coronary artery lesions is obtained from invasive coronary angiography (CAG). The clinical applicability and diagnostic performance of the newly developed 64-slice multislice computed tomography (MSCT) scanner in coronary angiographic evaluation is not well evaluated.

METHODS

Coronary computed tomography angiography (CCTA) was performed in 345 patients (119 women, 226 men; mean age, 59.64 +/- 11.67 years). Concomitant CAG was performed in 53 patients. The diagnostic performance of CCTA for detecting significant lesions was compared with that of CAG by 3 independent cardiologists.

RESULTS

All CCTA was performed without complication. Comparison between CCTA and CAG was made in the 53 patients who underwent both studies. Sensitivity, specificity and the positive and negative predictive values for the 53 patients were: 81%, 99%, 87% and 99%, respectively.

CONCLUSION

The 64-slice MSCT, developed in recent years, allows reliable noninvasive evaluation of coronary artery morphology, including plaque, stenosis and congenital anomaly. The diagnostic accuracy of MSCT scans for detecting lesions makes it a good imaging substitute for CAG in the evaluation of these coronary segments.

Relation of the metabolic syndrome to quantity of coronary atherosclerotic plaque

Although metabolic syndrome (MS) is associated with adverse cardiovascular outcomes, its association with the presence and extent of coronary atherosclerotic plaques is not well described. To assess this relation, multidetector computed tomography-based patterns of coronary plaque were assessed in 77 patients enrolled in the ROMICAT study (age 54 +/- 12 years; 79% Caucasians, and 36% women) and compared between those who did (n = 35; 45%) and did not (n = 42; 55%) have MS. The presence of any, calcified, and noncalcified plaque was significantly higher in patients with than without MS (91%, 74%, and 77% vs 46%, 45%, and 40% segments with plaque, respectively; all p <0.01). The overall number of segments with plaques was also higher in patients with MS (5.8 +/- 3.7 vs 2.1 +/- 3.3; p <0.001). MS was independently associated with both the presence and extent of overall plaques after adjusting for the Framingham risk score (odds ratio 6.7, 95% confidence interval 1.6 to 28.8, p <0.01 for presence, beta coefficient = 3.59 +/- 0.88 [SE], p = 0.009 for extent) and individual risk factors, including age, gender, smoking, body mass index, hypertension, diabetes, hyperlipidemia, and clinical coronary disease (odds ratio 8.4, 95% confidence interval 1.7 to 42.5, p = 0.008 for presence, beta coefficient = 2.35 +/- 0.86 [SE], p = 0.007 for extent). Similarly, MS was independently associated with calcified and noncalcified plaques individually. In conclusion, MS was independently associated with the presence and extent of both calcified and noncalcified coronary atherosclerotic plaques detected using multidetector computed tomography. These data may explain the higher cardiovascular risk in these patients and may lay the foundation for studies to determine whether such information may improve risk stratification.

MDCT of the myocardium: a new contribution to ischemic heart disease

RATIONALE AND OBJECTIVES

Despite the progress made in diagnosis and treatment, cardiovascular diseases remain the main cause of death worldwide.

MATERIALS AND METHODS

Multidetector row computed tomography (MDCT) provides several diagnostic insights, namely assessment of coronary artery anatomy and measurement of left ventricular volume and function. The ability of CT to show myocardial infarcted areas as an enhanced territory was described in the late 1970s in an animal model.

RESULTS

This method found a second wind with the arrival of MDCT technology that led to its clinical application. Several authors describe the ability of MDCT to assess myocardial injury both in animals and humans. The MDCT assessment of myocardial late enhancement is based on the same principle as delayed enhancement MRI.

CONCLUSIONS

The aim of this review is to cover the technical aspects of cardiac MDCT in assessing the myocardium and its potential in diagnosing ischemic heart disease.

Coronary 64-slice CT angiography predicts outcome in patients with known or suspected coronary artery disease

The aim of this study was to assess the prognostic value of 64-slice CT angiography (CTA) in patients with known or suspected coronary artery disease (CAD). Sixty-four-slice coronary CTA was performed in 220 patients [mean age 63 +/- 11 years, 77 (35%) female] with known or suspected CAD. CTA images were analyzed with regard to the presence and number of coronary lesions. Patients were followed-up for the occurrence of the following clinical endpoints: death, nonfatal myocardial infarction, unstable angina, and coronary revascularization. During a mean follow-up of 14 +/- 4 months, 59 patients (27%) reached at least one of the predefined clinical endpoints. Patients with abnormal coronary arteries on CTA (i.e., presence of coronary plaques) had a 1st-year event rate of 34%, whereas in patients with normal coronary arteries no events occurred (event rate, 0%, p < 0.001). Similarly, obstructive lesions (> or =50% luminal narrowing) on CTA were associated with a high first-year event rate (59%) compared to patients without stenoses (3%, p < 0.001). The presence of obstructive lesions was a significant independent predictor of an adverse cardiac outcome. Sixty-four-slice CTA predicts cardiac events in patients with known or suspected CAD. Conversely, patients with normal coronary arteries on CTA have an excellent mid-term prognosis.

CT and MRI of acute thoracic cardiovascular emergencies

A wide spectrum of acute cardiovascular disorders is seen in patients who are hospitalized in a critical care setting. Imaging plays a central role in the diagnosis and management of these conditions. The most frequently used imaging remains chest radiography; however, more advanced modalities, including coronary angiography, echocardiography, and radioisotope scintigraphy, have well established roles in the assessment of patients in the critical care setting. More recently, multidetector row CT (MDCT) and MRI are being used increasingly for evaluation of coronary artery disease, cardiac structure and function, coronary artery anomalies, cardiac masses, pericardial disease, valvular disease, postoperative cardiovascular abnormalities, venous thromboembolism and acute aortic syndromes, often with other ancillary findings that can provide important clinical information. The three most common life-threatening cardiovascular processes in which advanced imaging plays a role, particularly CT, are discussed, including pulmonary embolism, aortic dissection, and coronary artery disease.

Evaluation of acute coronary syndromes by cardiac magnetic resonance imaging

The use of cardiovascular magnetic resonance (CMR) imaging for the evaluation of patients with acute chest pain and acute coronary syndromes has great potential. The strength of CMR relies on its ability to provide information on anatomy, physiology, and function in a single scanning session in a noninvasive manner without the need for iodinated contrast, radiation, or the need to undergo invasive procedures. Specifically, with regard to imaging patients with acute chest pain and/or myocardial infarction (MI), CMR has the ability to qualitatively and quantitatively evaluate global and regional right and left ventricular systolic functions, myocardial edema, myocardial perfusion, and myocardial infarct size and transmurality/viability. This review will focus on CMR imaging for the following applications: (1) imaging for the evaluation of ventricular function and infarct size in patients with acute chest pain and/or acute MI, (2) for triage and prognosis of patients presenting to the emergency department with acute chest pain, (3) for evaluating patients after sustaining an acute MI, and (4) for stem cell research.

Detection of non-ST-elevation myocardial infarction and unstable angina in the acute setting: meta-analysis of diagnostic performance of multi-detector computed tomographic angiography

Background

Multi-detector computed tomography angiography (MDCTA) has been increasingly used in the evaluation of the coronary arteries. The purpose of this study was to review the literature on the diagnostic performance of MDCTA in the acute setting, for the detection of non-ST-elevation myocardial infarction (NSTEMI) and unstable angina pectoris (UAP).

Methods

A Pubmed and manual search of the literature published between January 2000 and June 2007 was performed. Studies were included that compared MDCTA with clinical outcome and/or CA in patients with acute chest pain, presenting at the emergency department. More specifically, studies that only included patients with initially negative cardiac enzymes suspected of having NSTEMI or UAP were included. Summary estimates of diagnostic odds ratio (DOR), sensitivity and specificity, negative (NLR) and positive likelihood ratio (PLR) were calculated on a patient basis. Random-effects models and summary receiver operating curve (SROC) analysis were used to assess the diagnostic performance of MDCTA with 4 detectors or more. The proportion of non assessable scans (NAP) on MDCTA was also evaluated. In addition, the influence of study characteristics of each study on diagnostic performance and NAP was investigated with multivariable logistic regression.

Results

Nine studies totalling 566 patients, were included in the meta-analysis: one randomised trial and eight prospective cohort studies. Five studies on 64-detector MDCTA and 4 studies on MDCTA with less than 64 detectors were included (32 detectors n = 1, 16 detectors n = 2, 16 and 4 detectors n = 1). Pooled DOR was 131.81 (95%CI, 50.90–341.31). The pooled sensitivity and specificity were 0.95 (95%CI, 0.90–0.98) and 0.90 (95%CI, 0.87–0.93). The pooled NLR and PLR were 0.12 (95%CI, 0.06–0.21) and 8,60 (95%CI, 5.03–14,69).

The results of the logistic regressions showed that none of the investigated variables had influence on the diagnostic performance or NAP

Conclusion

MDCTA of the coronary arteries performs good to excellent in the diagnosis of coronary artery disease in the acute setting and it can be used for early exclusion of NSTEMI or UAP in patients in the emergency department.

Dual-source CT for chest pain assessment

Comprehensive CT angiography protocols offering a simultaneous evaluation of pulmonary embolism, coronary stenoses and aortic disease are gaining attractiveness with recent CT technology. The aim of this study was to assess the diagnostic accuracy of a specific dual-source CT protocol for chest pain assessment. One hundred nine patients suffering from acute chest pain were examined on a dual-source CT scanner with ECG gating at a temporal resolution of 83 ms using a body-weight-adapted contrast material injection regimen. The images were evaluated for the cause of chest pain, and the coronary findings were correlated to invasive coronary angiography in 29 patients (27%). The files of patients with negative CT examinations were reviewed for further diagnoses. Technical limitations were insufficient contrast opacification in six and artifacts from respiration in three patients. The most frequent diagnoses were coronary stenoses, valvular and myocardial disease, pulmonary embolism, aortic aneurysm and dissection. Overall sensitivity for the identification of the cause of chest pain was 98%. Correlation to invasive coronary angiography showed 100% sensitivity and negative predictive value for coronary stenoses. Dual-source CT offers a comprehensive, robust and fast chest pain assessment.

Impact of 64-slice cardiac computed tomographic angiography on clinical decision-making in emergency department patients with chest pain of possible myocardial ischemic origin

To examine the impact of contrast enhanced multidetector computed tomography (MDCT) on clinical decision-making in patients who present to the emergency department (ED) with chest pain of possible ischemic origin, we studied 58 consecutive patients (age 56 +/- 10 years, 36% female) with chest pain, intermediate risk, and no ischemic electrocardiographic changes or increased biomarker measurements. After standard ED patient assessment including cardiology consultation, a diagnosis of acute coronary syndrome was made in 41 patients (71%), hospitalization was recommended in 47 (81%), and 32 (55%) were scheduled for an early invasive strategy. Patients underwent 64-slice contrast agent-enhanced MDCT with image reconstruction in multiple formats using retrospective electrocardiographic gating, which revealed normal (no or trivial atheroma) coronary vasculature in 15 patients, nonobstructive atheroma in 20 patients, and obstructive coronary disease (> or =1 luminal narrowing of > or =50%) in 23 patients. After MDCT, the diagnosis of acute coronary syndrome was revised in 18 of 41 patients (44%; 16 normal MDCT/widely patent stents, 2 alternative diagnoses), planned hospitalization canceled in 21 of 47 patients (45%; 13 normal MDCT/patent stent, 8 minor branch vessel disease), and planned early invasive strategy altered in 25 of 58 patients (43%; unnecessary in 20 of 32, advisable in 5 of 26 others). Effect of MDCT on clinical decisions was greater in the 36 patients without known preceding coronary disease. In 32 patients discharged from the ED (11 after initial triage, 21 patients after MDCT), there were no major adverse cardiac events (e.g., death, myocardial infarction, unplanned revascularization) during a 12-month follow-up period. In conclusion, contrast agent-enhanced 64-slice cardiac MDCT was a valuable diagnostic tool in the ED triage of patients with chest pain of possible ischemic origin and decreased the need for hospitalization by almost half in this patient cohort.

CT angiography: front line for acute coronary syndromes now?

See article on page 1386

Dual-source computed tomography in patients with acute chest pain: feasibility and image quality

The aim of this study was to determine the feasibility and image quality of dual-source computed tomography angiography (DSCTA) in patients with acute chest pain for the assessment of the lung, thoracic aorta, and for pulmonary and coronary arteries. Sixty consecutive patients (32 female, 28 male, mean age 58.1±16.3 years) with acute chest pain underwent contrast-enhanced electrocardiography-gated DSCTA without prior beta-blocker administration. Vessel attenuation of different thoracic vascular territories was measured, and image quality was semi-quantitatively analyzed by two independent readers. Image quality of the thoracic aorta was diagnostic in all 60 patients, image quality of pulmonary arteries was diagnostic in 59, and image quality of coronary arteries was diagnostic in 58 patients. Pairwise intraindividual comparisons of attenuation values were small and ranged between 1±6 HU comparing right and left coronary artery and 56±9 HU comparing the pulmonary trunk and left ventricle. Mean attenuation was 291±65 HU in the ascending aorta, 334±93 HU in the pulmonary trunk, and 285±66 HU and 268±67 HU in the right and left coronary artery, respectively. DSCTA is feasible and provides diagnostic image quality of the thoracic aorta, pulmonary and coronary arteries in patients with acute chest pain.

Role of cardiac computed tomography and magnetic resonance imaging in the evaluation of acute chest pain in the emergency department

Evaluation of patients presenting with chest pain to the emergency department remains a challenging task because of a variety of etiologies that range from benign to potentially fatal. Although majority of patients do not have myocardial ischemia as the cause of their presentation, the clinical work up can be time consuming, costly and inconclusive. Recent technical advances in cardiac computed tomography and magnetic resonance imaging have led to better diagnostic accuracy in evaluating patients with chest pain. In this paper, we review the role of cardiac computed tomography and magnetic resonance imaging in evaluating patients with chest pain in the emergency department.

New advances in cardiac computed tomography

PURPOSE OF REVIEW

Multidetector computed tomography has been growing in every way possible. The test is becoming more common in clinical practice. It has breached the public consciousness and is being asked for by name. Research in the field is accelerating. The technology is improving, as is our skill at interpretation. There have been hundreds of publications on the subject over the past year. We will address three of the most important recent areas of focus.

RECENT FINDINGS

Multidetector computed tomography has been touted as a possible 'triple rule-out' for myocardial infarction, pulmonary embolus, and aortic dissection, with an eye to improving emergency department efficiency and efficacy. A recent study has shown that, at least in low-risk patients, the triple rule-out is as safe as standard of care diagnosis, and saves considerable time and expense. Calcium scoring, hotly debated for years, has received approval from both the American Heart Association and American College of Cardiology as a screening test under certain circumstances. The 64-detector scanner has shown improvement over the 16-detector scanner.

SUMMARY

These developments indicate that multidetector computed tomography has more uses than previously realized. They also indicate that we have much more work to do before we can claim to have fully utilized this technology.

The role of cardiovascular imaging techniques in the assessment of patients with acute chest pain

Chest pain is the most common presenting symptom of coronary artery disease. The assessment and appropriate management of patients with acute chest pain and non-diagnostic electrocardiograms (ECGs) remain a continuing clinical problem, with major logistic and financial implications for health-care providers. Cardiovascular imaging is at the forefront of health care, experiencing rapid changes over the recent years, particularly with the use of advanced medical technologies. Imaging techniques like acute rest myocardial perfusion imaging (MPI), echocardiography, electron beam computed tomography (CT), cardiac magnetic resonance imaging (MRI) and multi-detector CT (MDCT) have been used recently in the evaluation and triage of patients with chest pain in addition to the conventional investigations such as ECGs and cardiac biomarkers in the chest pain units. The annual potential cost savings, by incorporating the routine use of acute rest MPI in patients with low-to-moderate risk and non-diagnostic ECGs are substantial. The high negative predictive value of a normal resting MPI in patients with chest pain for myocardial infarction and future cardiac events is well established. Echocardiography is also considered to be useful but the technique is operator dependent and at present there is insufficient data to support its use. Cardiac MRI is expensive and time consuming and there is insufficient diagnostic and prognostic data to make it suitable for chest pain patients at present. There has been increasing interest in MDCT recently, especially with the advent of 64-slice CT but the sensitivity and specificity in chest pain patients are no better than MPI so far.

Sixty-four–slice multidetector computed tomography: the future of ED cardiac care

Multidetector computed tomography (MDCT) imaging, a technological advance over traditional CT, is a promising possible alternative to cardiac catheterization for evaluating patients with chest pain in the emergency department (ED). In comparison with traditional CT, MDCT offers increased spatial and temporal resolution that allows reliable visualization of the coronary arteries. In addition, a "triple scan," which includes evaluation for pulmonary embolism and thoracic aortic dissection, can be incorporated into a single study. This test will enable emergency physicians to rapidly evaluate patients for life-threatening illnesses and may allow safer and earlier discharges of many patients with chest pain in comparison with a traditional rule-out protocol. In this article, we will highlight the technological advances of MDCT imaging, review the literature on coronary angiography via MDCT, and discuss the future of this technology as it relates to the ED.