Troponin-positive chest pain with unobstructed coronary arteries: definitive differential diagnosis using cardiac MRI

Objective

The purpose of this study was to assess the outcome of cardiac MRI (CMRI) with late gadolinium enhancement (LGE) at outpatient follow-up in a consecutive series of patients with troponin-positive chest pain but unobstructed coronary arteries at the index admission.

Methods

The study group comprised 91 consecutive patients who presented to our institution with cardiac chest pain, elevated troponin I and unobstructed coronary arteries on coronary angiography. All patients underwent an outpatient CMRI with LGE imaging in order to establish a definitive diagnosis.

Results

The average time from coronary angiography to LGE-CMRI was 2 months. 73% of patients had no abnormality on their LGE-CMRI, 16% of patients had patchy late enhancement consistent with myocarditis and 11% had focal subendocardial or full thickness late enhancement consistent with myocardial infarction. There were no deaths in this cohort during a mean follow-up of 21 months.

Conclusion

LGE-CMRI is a useful tool for establishing whether such patients have definitive evidence of non-ST-segment elevation myocardial infarction (NSTEMI), and can make an important contribution to the long-term management strategy of these patients as an inappropriate diagnosis of NSTEMI carries important medical, social and financial implications.Chest pain is one of the commonest indications for acute hospital admission in the UK [1]. A history of cardiac-sounding chest pain stimulates a series of investigations including electrocardiography (ECG) recordings and cardiac biomarkers as part of risk stratification [2]. A large body of evidence has demonstrated that, in patients with troponin-positive non-ST-segment elevation myocardial infarction (NSTEMI), early revascularisation is associated with a significant reduction in the rates of major adverse cardiac events (MACE) [3,4]. Current American and European guidelines recommend early angiography and revascularisation in this population. For this reason the vast majority of patients presenting with troponin-positive chest pain undergo coronary angiography with a view to revascularisation on the index admission.However, while the commonest reason for this presentation is NSTEMI due to atherosclerotic plaque rupture, there are other potential aetiologies, which include myocarditis or arrhythmia (particularly in the context of impaired left ventricular systolic function). Up to 10% of patients referred for angiography with troponin-positive chest pain have unobstructed coronary arteries [5,6]. This cohort of patients presents a diagnostic dilemma and as a result their subsequent management is heterogeneous. National and international guidelines lead us to an apparent diagnosis of NSTEMI [2,7] for patients presenting in this fashion. Given that it is possible for plaque rupture to occur at the site of a “non-obstructive” stenosis, which is generally defined as <50% by visual assessment on angiography, the finding of non-obstructed coronary arteries does not fully exclude the diagnosis of NSTEMI. By contrast, in many such cases, the true reason for admission may not be NSTEMI, with a differential diagnosis of myopericarditis most often considered. The management strategy adopted for this cohort of patients is variable. Many such patients are committed to post-myocantial infarction (MI) secondary prevention treatment for presumed NSTEMI and retain this diagnostic label. This in turn carries important potential implications for lifestyle outcomes, such as driving as well as insurance and job applications.The development of late gadolinium enhancement (LGE) cardiac MRI (CMRI) provides a sensitive and specific tool for the detection of even small amounts of myocardial damage [8]. This group and others have previously described the application of CMRI for differentiation of myocardial damage due to coronary occlusion or inflammation [9-11]. Furthermore, the clinical implications of detecting no LGE in such patients is uncertain as the underlying cause for the troponin release remains unexplained.The aim of this study was to assess the outcome of LGE-CMRI at outpatient follow-up in a consecutive series of patients who had presented to this regional cardiac centre with troponin-positive chest pain but who had no obstructive coronary artery disease at angiography on the index admission. We also sought to identify the relative proportions of patients with (a) no LGE, (b) LGE typical of MI and (c) patchy LGE typical of myocarditis in the largest cohort of such patients reported so far.     

Value of sonographic screening for gallstones in patients with chest pain and normal coronary arteries

The prevalence of sonographically detectable gallstones in patients with chest pain and normal coronary arteries was compared with the prevalence of gallstones in patients referred to sonography for nonbiliary disease. Among 545 patients with chest pain and normal coronary arteriograms, 101 (18.5%) were referred for sonographic examination of the gallbladder. This test group was compared to a matched control group (n = 101) undergoing abdominal sonography for nonbiliary disease. Six patients (5.9%) in the test group and eight patients (7.9%) in the control group were found to have gallstones by accepted sonographic criteria. Studies based on oral cholecystogram screening of healthy populations have claimed a prevalence of cholelithiasis of 2.3%-6.2% for males and 2.3%-12% for females. The authors were unable to demonstrate a higher prevalence of sonographically identified gallstones in patients with chest pain and normal coronary arteries than in patients examined for nonbiliary disease. The frequency of gallstones in this test group is comparable to that reported for a screened population of healthy men and women.     

Assessment of coronary flow reserve by sestamibi imaging in patients with typical chest pain and normal coronary arteries

Purpose We assessed coronary flow reserve (CFR) by sestamibi imaging in patients with typical chest pain, positive exercise stress test and normal coronary vessels. Methods Thirty-five patients with typical chest pain and normal angiogram and 12 control subjects with atypical chest pain underwent dipyridamole/rest ^99mTc-sestamibi imaging. Myocardial blood flow (MBF) was estimated by measuring first transit counts in the pulmonary artery and myocardial counts from SPECT images. Estimated CFR was expressed as the ratio of stress to rest MBF. Rest MBF and CFR were corrected for rate–pressure product (RPP) and expressed as normalised MBF (MBF_n) and normalised CFR (CFR_n). Coronary vascular resistances (CVR) were calculated as the ratio between mean arterial pressure and estimated MBF. Results At rest, estimated MBF and MBF_n were lower in controls than in patients (0.98 ± 0.4 vs 1.30 ± 0.3 counts/pixel/s and 1.14 ± 0.5 vs 1.64 ± 0.6 counts/pixel/s, respectively, both p < 0.02). Stress MBF was not different between controls and patients (2.34 ± 0.8 vs 2.01 ± 0.7 counts/pixel/s, p=NS). Estimated CFR was 2.40 ± 0.3 in controls and 1.54 ± 0.3 in patients (p < 0.0001). After correction for the RPP, CFR_n was still higher in controls than in patients (2.1 ± 0.5 vs 1.29 ± 0.5, p < 0.0001). At baseline, CVR values were lower (p < 0.01) in patients than in controls. Dipyridamole-induced changes in CVR were greater (p < 0.0001) in controls (−63%) than in patients (−35%). In the overall study population, a significant correlation between dipyridamole-induced changes in CVR and CFR was observed (r = −0.88, p < 0.0001). Conclusion SPECT might represent a useful non-invasive method for assessing coronary vascular function in patients with angina and a normal coronary angiogram.     

Validation of a clinical decision rule: chest X-ray in patients with chest pain and possible acute coronary syndrome

Current literature suggests that a large proportion of chest X-rays (CXRs) performed in emergency department (ED) patients with chest pain and suspected acute coronary syndrome (ACS) are unnecessary. The Canadian ACS Guidelines aim to guide clinicians in the appropriate use of CXR within this patient population. This study determined the prevalence of clinically significant CXR abnormalities and assessed the utility of the guidelines in a population of ED patients with chest pain and suspected ACS. Included in the study were participants over the age of 18 who presented to an Australian metropolitan ED, over a 1-year period, with a primary complaint of chest pain and who had a CXR and troponin level ordered in the ED (N?=?760). We retrospectively compared their radiographic findings with their recommendations for CXR according to the ACS Guidelines. We found that 12 % of the participants had a clinically significant chest X-ray. The guidelines had a sensitivity of 80 % (95 % CI 0.70–0.87) and specificity of 50 % (95 % CI 0.47–0.54). The positive predictive value was 18 % (95 % CI 0.15–0.22) with a 95 % negative predictive value (95 % CI 0.92–0.97). Had the ACS guidelines been applied to our patient population, the number of CXR performed would have been reduced by 47 %. This study suggests that the ACS Guidelines has the potential to reduce the numbers of unnecessary CXR performed in ED patients. However, this would come at the expense of missing a minority of significant CXR abnormalities.     

急性胸痛患者总冠状动脉钙化和局部钙化的差异与急性冠脉综合征及主要病变之间的关系

目的 探讨急性冠状动脉综合征(ACS)总冠状动脉钙化(CAC)负荷和局部CAC与主要病变之间的关系.方法 对37例ACS患者及223例对照患者进行计算机CAC检查和CT血管造影评估显著狭窄和高风险斑块的表现,测量总评分和节段Agatston评分.对ACS患者的主要病变进行评价.结果 37例ACS患者的CAC总评分较非A...     

光学相干层析成像评价非ST段抬高型急性冠状动脉综合征患者靶血管中薄帽纤维粥样斑块分布

目的 采用光学相干层析成像(OCT)观察薄帽纤维粥样斑块(TCFA)在非ST段抬高型急性冠状动脉综合征(NSTE-ACS)患者靶血管中的自然分布.方法 采用OCT对斑块脂质含量进行半定量评价(角度或象限),测量靶血管开口至纤维帽最薄处距离.结果 选择2013年6月至2015年3月住院治疗的连续NSTE-ACS患者33例,其中不稳定型心绞痛24例,非ST段抬高型心肌梗死9例.OCT共检出74处病变;45处靶病变;其中TCFA病变38处(51.4％),非TCFA病变36处(48.6％).前降支18处TCFA主要集中在近段,其中近段30 mm内13处(72.2％),40 mm内16处(88.9％);回旋支9处TCFA平均分布于整个靶血管,近段距开口30 mm内仅有3个(33.3％);右冠状动脉11处TCFA也平均分布在各段,近段距开口30 mm内仅有4个(36.4％).结论 NSTE-ACS患者靶血管中TCFA病变更趋于分布在前降支近段,在回旋支和右冠状动脉中则趋于平均分布.     

比较急性胸痛非洲裔美国人和白种人冠状动脉粥样硬化的冠状动脉CTA表现特征

目的利用冠状动脉CT血管成像(CTA)比较研究急性胸痛的非洲裔美国人和白种人之间的动脉粥样硬化斑块病变的发生率、程度与成分。材料与方法本回顾性研究符     

Multislice CT in emergency room management of patients with chest pain and medium-low probability of acute coronary syndrome

PURPOSE: The main cause of acute chest pain, which accounts for 6.5% of urgent medical examinations in emergency rooms in Italy, is acute coronary syndrome (ACS). We performed this prospective study to evaluate the diagnostic accuracy of a 16-channel computed tomography (CT) scanner with dedicated software in a group of patients with chest pain and medium to low risk of ACS. MATERIALS AND METHODS: This study involved a selected group of 31 patients reporting chest pain with a medium to low probability of ACS, defined on the basis of preliminary tests [electrocardiogram (ECG) and serum cardiac markers]. Coronary angiography, performed within 24 h of MSCT, was used as the gold standard. RESULTS: MSCT identified the presence of occlusions and significant (>50%) or nonsignificant stenoses in the main coronary segments, with a sensitivity of 65%, a specificity of 98.8%, a positive predictive value (PPV) of 81.2%, a negative predictive value (NPV) of 97.3% and an accuracy of 96.4%. Significant stenoses and occlusions were detected with a sensitivity of 71.4%, a specificity of 99.6%, a PPV of 93.7%, an NPV of 97.7% and an accuracy of 97.5%. CONCLUSIONS: Due to its high NPV, this technique can rule out significant stenoses or coronary occlusions provided that image quality is excellent. In patients with a medium to low coronary risk, MSCT is a more accurate indicator of the need for coronary angiography than is exercise stress testing, which is less expensive but has lower predictive values.     

Predictors of image quality of coronary computed tomography in the acute care setting of patients with chest pain

Objective

We aimed to determine predictors of image quality in consecutive patients who underwent coronary computed tomography (CT) for the evaluation of acute chest pain.

Method and materials

We prospectively enrolled patients who presented with chest pain to the emergency department. All subjects underwent contrast-enhanced 64-slice coronary multi-detector CT. Two experienced readers determined overall image quality on a per-patient basis and the prevalence and characteristics of non-evaluable coronary segments on a per-segment basis.

Results

Among 378 subjects (143 women, age: 52.9 ± 11.8 years), 345 (91%) had acceptable overall image quality, while 33 (9%) had poor image quality or were unreadable. In adjusted analysis, patients with diabetes, hypertension and a higher heart rate during the scan were more likely to have exams graded as poor or unreadable (odds ratio [OR]: 2.94, p = 0.02; OR: 2.62, p = 0.03; OR: 1.43, p = 0.02; respectively). Of 6253 coronary segments, 257 (4%) were non-evaluable, most due to severe calcification in combination with motion (35%). The presence of non-evaluable coronary segments was associated with age (OR: 1.08 annually, 95%-confidence interval [CI]: 1.05-1.12, p < 0.001), baseline heart rate (OR: 1.35 per 10 beats/min, 95%-CI: 1.11-1.67, p = 0.003), diabetes, hypertension, and history of coronary artery disease (OR: 4.43, 95%-CI: 1.93-10.17, p < 0.001; OR: 2.27, 95-CI: 1.01-4.73, p = 0.03; OR: 5.12, 95%-CI: 2.0-13.06, p < 0.001; respectively).

Conclusion

Coronary CT permits acceptable image quality in more than 90% of patients with chest pain. Patients with multiple risk factors are more likely to have impaired image quality or non-evaluable coronary segments. These patients may require careful patient preparation and optimization of CT scanning protocols.     

双源CT在急性胸痛诊断和鉴别诊断中的临床价值

目的：探讨双源CT在急性胸痛诊断和鉴别诊断中的临床价值。方法：51例急性胸痛患者行双源CT心脏及胸部血管检查,对图像进行重组并进行诊断,其中36例患者双源CT结果并与血管造影结果进行对比较。结果：所有患者一次心脏和胸部血管双源CT检查即可快速获得清晰的冠状动脉、肺动脉、胸主动脉及胸部其他结构。双源CT诊断冠状动脉狭窄或闭塞26例,其中5例并发急性心肌梗死,1例合并有冠状动脉夹层;肺动脉栓塞7例,胸主动脉夹层、壁间血肿和动脉瘤分别为6例、2例和2例。冠状动脉及胸主动脉双源CT结果与血管造影结果具有良好的一致性。结论：双源CT可以同时清晰地显示心脏及胸部血管,是急性胸痛病因诊断和鉴别诊断的无创、快速、可靠的检查方法。     

Usefulness of multislice spiral computed tomography coronary angiography in patients with acute chest pain in the emergency department

Background

Despite reports that multislice spiral computed tomography (MSCT) has high sensitivity and specificity in preselected patient populations, the routine clinical feasibility and utility of MSCT coronary angiography in patients with acute chest pain in the emergency department remains uncertain.

Objectives

We sought to determine whether 16-slice MSCT coronary angiography can provide diagnostically useful images in patients with acute chest pain in the emergency department.

Methods

Ninety-eight patients in the emergency department (41 men, 57 women; mean age ± SD, 48.1 ± 11.9 y) with acute chest pain underwent MSCT coronary angiography. Coronary calcium (Agatston) scoring was performed, followed by contrast-enhanced MSCT. Images were evaluated for mean image quality (MIQ) and for degree of stenosis. These data were correlated with body mass index (BMI; in kg/m²), heart rate, beat-to-beat variation, and calcium score to assess their influence on image quality.

Results

The 28 patients (29%) with nondiagnostic MIQs had significantly higher BMIs (mean ± SD, 32.9 ± 9.1 vs 28.9 ± 6.7; P < 0.05) and heart rates (mean ± SD, 71.0 ± 11.9 beats/min vs 65.6 ± 9.9 beats/min; P < 0.05) than patients with diagnostic MIQs. Forty-five patients (46%) had at least 1 nondiagnostic coronary segment. These patients had significantly higher heart rates (mean ± SD, 70.5 ± 10.3 vs 64.1 ± 13.7; P < 0.05) than patients with only diagnostic-quality scans. Image quality correlated inversely and strongly with BMI and heart rate.

Conclusions

Sixteen-slice MSCT coronary angiography cannot routinely provide diagnostically useful images in patients with acute chest pain in the emergency department.     

Perfusion impairment in patients with normal-appearing coronary arteries: identification with contrast-enhanced MR imaging

PURPOSE: To prospectively determine the feasibility of using first-pass magnetic resonance (MR) imaging to distinguish between myocardial segments in patients with coronary artery disease (CAD) of different degrees of obstruction and those in patients with normal-appearing coronary arteries. MATERIALS AND METHODS: The study was approved by the institutional ethics committee, and all patients provided informed consent. First-pass contrast material-enhanced MR imaging was performed at rest and after the infusion of dipyridamole in 37 patients (29 men, eight women; mean age, 57.2 years +/- 10.5 [standard deviation]) who had positive exercise test results or a clinical history of CAD. Myocardial segments were divided into five groups according to the degree of obstruction in the supplying artery. Signal intensity upslope, peak signal intensity, and time to peak signal intensity, as well as hyperemia-to-rest (HR) ratios for each of these three variables, were analyzed for each segment by using a generalized linear model. RESULTS: Signal intensity upslope in patients with normal coronary arteries at angiography was significantly higher than that in patients with CAD (P < .001). Signal intensity upslope for segments in patients without CAD was significantly different from that for normal-appearing segments in patients with CAD (P < .001). Signal intensity upslope (P < .05) and peak signal intensity (P < .01) enabled the differentiation of segments with more than 70% reduction in luminal diameter from those in all other groups. HR ratios demonstrated findings that were similar to those obtained by using each signal intensity variable alone. CONCLUSION: First-pass MR imaging can be used to distinguish segments with different degrees of obstructive CAD. Importantly, MR imaging can help identify segments with impaired perfusion and normal-appearing coronary arteries in patients with CAD and can demonstrate obstructive lesions in other territories.     

双源CT前瞻性心电门控扫描在急性胸痛诊断中的临床应用

目的 探讨双源CT(DSCT)前瞻性心电门控扫描在急性胸痛诊断中的临床应用,并比较前瞻性心电门控与回顾性心电门控2种扫描技术的图像质量和辐射剂量.方法 连续搜集30例[A组,平均心率≥85次/min(bpm)]临床症状表现为急性胸痛并行DSCT前瞻性心电门控心胸联合血管成像的患者,连续搜集30例(B组,所有患者平均心率≥85 bpm)表现为急性胸痛行DSCT回顾性心电门控扫描的患者.对2组患者的冠状动脉、肺动脉及主动脉分别进行靶重组,评价2组图像质量,并对疾病进行诊断;应用x2检验和两独立样本t检验比较2组患者的图像质量和有效剂量.结果 A、B组可评价冠状动脉节段比例分别为98.44%(379/385)和98.48%(390/396),差异无统计学意义(x2=0.002,P=0.961);A、B组间图像噪声[分别为(16.23±5.75)、(16.31±3.32)HU]、信噪比(分别为26.85±9.94、24.78±9.91)及对比度噪声比(分别为20.99±9.31、18.65±8.72)差异均无统计学意义(t值分别为0.069、0.908、1.224,P值均＞0.05);A、B 2组有效剂量分别为(8.37±2.69)和(20.05±5.52)mSv,差异有统计学意义(t=9.401,P=0.000).结论 DSCT前瞻性心电门控心胸联合血管成像可以获得与回顾性心电门控扫描相似的图像质量,且辐射剂量降低.

Abstract：

Objective To evaluate the application of prospective ECG-gated dual source CT (DSCT) in patients with acute chest pain, and compare it's image quality and radiation dose with those of retrospective ECG-gated spiral scan. Methods Thirty consecutive patients (Group A, average HR ≥85 bpm) with acute chest pain were scanned with prospective ECG-gated scan and another 30 consecutive patients (Group B, average HR ≥85 bpm)were analyzed by retrospective ECG-gated scan. Tube voltage and tube current were adapted by the BMI of patients. MPR, MIP, CPR and VR were used to display pulmonary arteries (PA), thoracic aorta and coronary arteries (CA). Image quality as well as radiation dose were assessed in 2 groups. Qualitative image quality was compared with chi-square test between the two groups,while quantitative image quality [the image noise ( IN ), signal-to-noise ratio ( SNR ) and contrast-to-noise ratio(CNR)] and radiation dose were evaluated with x2 test and Student's t test. Results The proportion of valid coronary segments for diagnosis were 379/385 ( 98. 44% ) and 390/396 ( 98.48% ) respectively in Group A and Group B with no significant difference(x2 =0. 002,P =0. 961 ). The IN [( 16. 23 ±5.75)vs ( 16. 31 ±3. 32) HU] ,SNR (26. 85 ±9. 94 vs 24. 78 ±9. 91 ) and CNR (20. 99 ±9. 31 vs 18. 65 ±8. 72)showed no significant differences between 2 groups ( t = 0. 069,0. 908 and 1. 224, P ＞ 0. 05, respectively).The ED was on average ( 8. 37 ± 2. 69 ) mSv in Group A, whereas on average ( 20. 05 ± 5.52 ) mSv in Group B. There was a statistical difference between 2 groups ( t = 9. 401, P = 0. 000). Conclusion Low dose prospective ECG-gated DSCT angiography can show similar image quality as retrospective ECG-gated spiral scan with radiation dose.     

MDCT angiography and coronary catheter angiography in patients with chest pain which is first

Back ground

In some patients suffering from chest pain, we must start by non-invasive coronary CT angiography (CCTA) to protect these patients from unnecessary invasive coronary catheter angiography (CCA).

急性胸痛病人CT冠状动脉成像显示的冠状动脉粥样硬化斑块中除钙化外其他成分的预后价值

摘要目的应用CT冠状动脉成像检查进行系统性评估无证据表明为急性冠状动脉综合征(ACS)的急性胸痛病人的预后情况,不仅仅评价冠状动脉钙化(CAC)的情况。材料与方法人类研究委员会批准本项研究,并确定无需书面知情同意。