Computed tomography pulmonary angiography in the diagnosis of acute pulmonary embolism in the emergency department

This study was undertaken to evaluate the use of computed tomography pulmonary angiography (CTPA) in patients with pulmonary embolism (PE) who were followed in the emergency department (ED). The files and computer records of 850 patients older than 16 years of age who were seen in the Hacettepe University Hospital ED between April 10, 2001, and December 1, 2005, and who required CTPA for PE prediagnosis and/or another diagnosis, were studied retrospectively. PE was identified by CTPA in 9.4% of 416 women and in 5.8% of 434 men. A significant difference (P< .05) was noted in the women and men in whom PE was detected. The mean age of the patients was 58.13±17.88 y (range, 16–100 y). Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for clinical susceptibility to PE among patients who underwent CTPA were assessed at 95.3%, 48.2%, 13%, and 99.2%, respectively. CTPA was done for different reasons: aortic aneurysm dissection (n=1), cough distinctive diagnosis (n=1), dyspnea distinctive diagnosis (n=6), chest pain distinctive diagnosis (n=3), PE prediagnosis (n=51), and other reasons (n=2). Also, sensitivity, specificity, PPV, and NPV were found to be 95.4%, 16.2%, 14.4%, and 96%, respectively, for D-dimer. CTPA, which is accessible on a 24-h basis in the ED, is a valuable tool for the diagnosis of PE.     

Clinical probability and alveolar dead space measurement for suspected pulmonary embolism in patients with an abnormal D-dimer test result

BACKGROUND: Most patients with suspected pulmonary embolism (PE) have a positive D-dimer test and undergo diagnostic imaging. Additional non-invasive bedside tests are required to reduce the need for further diagnostic tests. OBJECTIVES: We aimed to determine whether a combination of clinical probability assessment and alveolar dead space fraction measurement can confirm or exclude PE in patients with an abnormal D-dimer test. METHODS: We assessed clinical probability of PE and alveolar dead space fraction in 270 consecutive in- and outpatients with suspected PE and positive D-dimer. An alveolar dead space fraction < 0.15 was considered normal. PE was subsequently excluded or confirmed by venous compression ultrasonography, spiral computed tomography and a 3-month follow-up. Radiologists were unaware of the results of clinical probability and capnography. RESULTS: PE was confirmed in 108 patients (40%). Capnography had a sensitivity of 68.5% (95% confidence interval [CI]: 58.9-77.1%) and a specificity of 81.5% (95% CI: 74.6-87.1%) for PE. Forty-five patients (16.6%) had both a low clinical probability and normal capnography (sensitivity: 99.1%, 95% CI: 94.9-100%) and 34 patients (12.6%) had both a high clinical probability and abnormal capnography (specificity: 100%, 95% CI: 97.7-100%). CONCLUSION: Capnography alone does not exclude PE accurately. The combination of clinical probability and capnography accurately excludes or confirms PE and avoids further testing in up to 30% of patients.     

Use of spiral computed tomography contrast angiography and ultrasonography to exclude the diagnosis of pulmonary embolism in the emergency department

Spiral computed tomography (CT) contrast angiography is a promising imaging modality for the diagnosis of pulmonary embolism but the negative predictive value of this test remains controversial. We performed a multi-center prospective cohort study to determine the safety of relying on a negative spiral CT contrast angiography scan to exclude pulmonary embolism. Patients presenting to the Emergency Departments of three tertiary care institutions with clinically suspected pulmonary embolism were potentially eligible for the study. Patients underwent a clinical evaluation to categorize pretest probability into low, moderate, and high categories, and had D-dimer testing performed. Patients at low pretest probability with normal D-dimer were considered to have pulmonary embolism excluded. The remaining patients underwent spiral CT contrast angiography scan of the pulmonary arterial circulation and bilateral venous ultrasound of the proximal leg veins. Patients who were confirmed to have pulmonary embolism or deep vein thrombosis were treated with anticoagulant therapy. Patients in whom the diagnosis of pulmonary embolism was excluded did not receive anticoagulant therapy and were followed for a 3-month period for the development of venous thromboembolic complications. Eight hundred fifty-eight (858) patients were enrolled in this study. Three-hundred sixty-nine (369) patients had low pretest probability and negative D-dimer results and no further diagnostic tests were performed. None of these patients subsequently developed venous thromboembolic complications (0%, 95% confidence interval [CI] 0% to 1.0%). The remaining 489 were referred for spiral CT contrast angiography scan and ultrasound. Sixty-seven patients were confirmed to have pulmonary embolism and an additional 15 patients with negative CT scans had proximal deep vein thrombosis (DVT) on ultrasound for a total prevalence of venous thromboembolism of 82/489 (16.8%). Two of 409 patients who had pulmonary embolism excluded in the initial evaluation phase developed proximal venous thromboembolism (0.5%; 95% CI 0% to 1.8%) in the 3-month follow-up period. These findings suggest that the combination of a negative spiral CT contrast angiography scan and normal venous ultrasound imaging safely excludes the diagnosis of pulmonary embolism in the Emergency Department setting.     

Contrast nephropathy following computed tomography angiography of the chest for pulmonary embolism in the emergency department

OBJECTIVE: To estimate the frequency of contrast nephropathy after computed tomography angiography (CTA) to rule out pulmonary embolism (PE) in the emergency department (ED) setting. METHODS: We prospectively followed patients undergoing CTA for PE, while in the ED, for 45 days. Patients who refused follow-up or were receiving hemodialysis were excluded. Severe renal failure was defined as an increase in creatinine > or = 3.0 mg dL(-1) or a need for hemodialysis within the follow-up period. Patients were also followed for laboratory-defined contrast nephropathy, defined as an increase in creatinine of > 0.5 mg dL(-1) or > 25%, within seven days following CTA. RESULTS: A total of 1224 patients were followed, and 354 [29%, 95% confidence interval (CI): 26-32%] patients had paired (preCTA and post-CTA) creatinine measurements. None developed renal failure (0/1224; 0%, CI: 0-0.3%). 44 patients developed laboratory-defined contrast nephropathy, corresponding to an overall frequency of 4% (44/1224; CI: 3-5%) and 12% (44/354; 95% CI: 9-16%) among those with paired creatinine measurements. CONCLUSIONS: Following CTA for PE, the incidence of severe renal failure was very low, but the incidence of laboratory-defined contrast nephropathy (4% overall and 12% of those with paired measurements) was higher than expected.     

The YEARS algorithm for suspected pulmonary embolism: shorter visit time and reduced costs at the emergency department

Essentials

• The YEARS algorithm was designed to simplify the diagnostic workup of suspected pulmonary embolism.
• We compared emergency ward turnaround time of YEARS and the conventional algorithm.
• YEARS was associated with a significantly shorter emergency department visit time of ?60 minutes.
• Treatment of pulmonary embolism was initiated 53 minutes earlier with the YEARS algorithm

Summary

Background

Recently, the safety of the YEARS algorithm, designed to simplify the diagnostic work‐up of pulmonary embolism (PE), was demonstrated. We hypothesize that by design, YEARS would be associated with a shorter diagnostic emergency department (ED) visit time due to simultaneous assessment of pre‐test probability and D‐dimer level and reduction in number of CT scans.

Aim

To investigate whether implementation of the YEARS diagnostic algorithm is associated with a shorter ED visit time compared with the conventional algorithm and to evaluate the associated cost savings.

Methods

We selected consecutive outpatients with suspected PE from our hospital included in the YEARS study and ADJUST‐PE study. Different time‐points of the diagnostic process were extracted from the to‐the‐minute accurate electronic patients’ chart system of the ED. Further, the costs of the ED visits were estimated for both algorithms.

Results

All predefined diagnostic turnaround times were significantly shorter after implementation of YEARS: patients were discharged earlier from the ED; 54 min (95% CI, 37–70) for patients managed without computed tomography pulmonary angiography (CTPA) and 60 min (95% CI, 44–76) for the complete study population. Importantly, patients diagnosed with PE by CTPA received the first dose of anticoagulants 53 min (95% CI, 22–82) faster than those managed according to the conventional algorithm. Total costs were reduced by on average €123 per visit.

Conclusion

YEARS was shown to be associated with a shorter ED visit time compared with the conventional diagnostic algorithm, leading to faster start of treatment in the case of confirmed PE and savings on ED resources.

     

Clinical probability score and D-dimer estimation lack utility in the diagnosis of childhood pulmonary embolism

Summary.  Background : Childhood pulmonary embolism (PE) causes significant mortality and evidence suggests that it is under-diagnosed. Clinical probability scores and D-dimer estimation to assess pre-test probability have not been studied in children with suspected PE. Patients/Methods : This retrospective cohort study evaluated Wells simplified probability score for PE in 50 children with PE and 25 PE negative control patients, and D-dimer values in 27 PE positive and 12 PE negative children. Results : PE positive and PE negative groups had similar rates of risk factors for venous thromboembolism (VTE). Wells simplified probability score showed a small difference between PE positive and PE negative children (median score: PE positive, 4.5; PE negative, 4; P  =   0.009), children with PE are more likely to obtain a 'PE likely' score (score > 4), P  =   0.012. The difference was of slightly greater significance when the Wells score was adjusted to account for pediatric normal ranges for heart rate, P  =   0.007, and signs/symptoms of upper limb DVT, P  =   0.006. Children with PE were as likely as PE negative patients to have a D-dimer value within the normal range (PE positive, 15%; PE negative, 25%; P  =   0.654). A combination of a 'PE unlikely' score and normal D-dimer value occurred in 1/12 (8%) of PE negative children. Conclusions : The Wells clinical probability score and D-dimer estimation may lack utility in the determination of pre-test probability of PE in children. Validation of a pediatric clinical probability score, incorporating D-dimer estimation, by prospective study, would be difficult as a result of the rarity of childhood PE.     

The use of D-dimer testing and Wells score in patients with high probability for acute pulmonary embolism

Rationale, aims and objective  To investigate if a combination of Wells pre-test probability score and D-dimer testing could be used as a safe base for making clinical decisions on further investigations for patients with intermediate to high risks of pulmonary embolism (PE).
Methods  One hundred and twenty patients with signs or symptoms of acute PE were investigated with pulmonary angiography (PA) or contrast enhanced computed tomography of the pulmonary arteries (CTPA), D-dimer testing (Tinaquant^®) and clinical scoring using the Wells pre-test probability score during their first 48 hours at the hospital. Patients were recruited consecutively from emergency departments at two teaching hospitals.
Results  The cut-off value of 0.5 mg L⁻¹ in D-dimer analysis is proved adequate with a negative predictive value (NPV) of 92% in this group of patients with intermediate to high risks. The combination of D-dimer testing and Wells score increases the NPV to 94%. The specificities of both tests were low.
Conclusion  D-dimer and Wells pre-test probability scores are safe to rule out acute PE even in patients with at least an intermediate risk of PE, but the specificity is low. D-dimer testing had a higher NPV than Wells score and the combination improved the algorithm further. The cut-off level for a high risk of PE measured with the Wells score was four and it seems reasonable to use that cut-off level in future algorithms. In addition, both PA and CTPA can present false positive and negative results difficult to interpret.     

Investigating pulmonary embolism in the emergency department with lower limb plethysmography: the Manchester Investigation of Pulmonary Embolism Diagnosis (MIOPED) study

Objectives

To measure the diagnostic accuracy of computerised strain gauge plethysmography in the diagnosis of pulmonary embolism (PE).

Methods

Two researchers prospectively recruited 425 patients with pleuritic chest pain presenting to the emergency department (ED). Lower limb computerised strain gauge plethysmography was performed in the ED. All patients underwent an independent reference standard diagnostic algorithm to establish the presence or absence of PE. A low modified Wells'' clinical probability combined with a normal D‐dimer excluded PE. All others required diagnostic imaging with PIOPED interpreted ventilation perfusion scanning and/or computerised tomography (CT) pulmonary angiography. Patients with a nondiagnostic CT had digital subtraction pulmonary angiography. All patients were followed up clinically for 3 months.

Results

The sensitivity of computerised strain gauge plethysmography was 33.3% (95% confidence interval (CI) 16.3 to 56.2%) and specificity 64.1% (95% CI 59.0 to 68.8%). The negative likelihood ratio was 1.04 (95% CI 0.68 to 1.33) and positive likelihood ratio 0.93 (95% CI 0.45 to 1.60).

Conclusions

Lower limb computerised strain gauge plethysmography does not aid in the diagnosis of PE.     

Emergency department focused bedside echocardiography in massive pulmonary embolism

Background

Massive pulmonary embolism (PE) is a common consideration in unstable patients presenting to the emergency department (ED) with chest pain, dyspnea, or cardiac arrest. It is a potentially lethal condition necessitating prompt recognition and aggressive management. Conventional diagnostic modalities in the ED, including chest computed tomography angiography and ventilation-perfusion scanning, require the unstable patient to leave the department, and raise concerns over renal injury. Several case reports document findings of massive PE on echocardiography performed in the ED; however, none was performed, interpreted, and acted upon in the form of thrombolytic therapy by an emergency physician without the additional benefit of a cardiologist’s interpretation or a confirmatory imaging study.

Objective

We present a case that illustrates the utility of ED focused bedside echocardiography in suspected massive PE and briefly review direct and indirect ultrasound findings of acute PE.

Case Report

A case of massive PE in a 61-year-old woman is reported. In this patient with marked dyspnea, progressive hemodynamic instability, and contraindications to definitive imaging, ED focused bedside echocardiography provided valuable information that strongly suggested the diagnosis and led to alteplase administration. To our knowledge, this case represents the first report of thrombolytic therapy administration for acute massive PE based solely on clinical presentation and an emergency physician-performed bedside echocardiogram.

Conclusion

In the hands of an experienced emergency physician ultrasonographer, ED focused bedside echocardiography provides a safe, rapid, and non-invasive diagnostic adjunct for evaluation of the patient suspected of having massive PE.     

Clinical criteria to prevent unnecessary diagnostic testing in emergency department patients with suspected pulmonary embolism.

Overuse of the d-dimer to screen for possible pulmonary embolism (PE) can have negative consequences. This study derives and tests clinical criteria to justify not ordering a d-dimer. The test threshold was estimated at 1.8% using the method of Pauker and Kassirer. The PE rule-out criteria were derived from logistic regression analysis with stepwise backward elimination of 21 variables collected on 3148 emergency department patients evaluated for PE at 10 US hospitals. Eight variables were included in a block rule: Age < 50 years, pulse < 100 bpm, SaO(2) > 94%, no unilateral leg swelling, no hemoptysis, no recent trauma or surgery, no prior PE or DVT, no hormone use. The rule was then prospectively tested in a low-risk group (1427 patients from two hospitals initially tested for PE with a d-dimer) and a very low-risk group (convenience sample of 382 patients with chief complaint of dyspnea, PE not suspected). The prevalence of PE was 8% (95% confidence interval: 7-9%) in the low-risk group and 2% (1-4%) in the very low-risk group on longitudinal follow-up. Application of the rule in the low-risk and very low-risk populations yielded sensitivities of 96% and 100% and specificities of 27% and 15%, respectively. The prevalence of PE in those who met the rule criteria was 1.4% (0.5-3.0%) and 0% (0-6.2%), respectively. The derived eight-factor block rule reduced the pretest probability below the test threshold for d-dimer in two validation populations, but the rule's utility was limited by low specificity.     

D-二聚体是筛除低临床概率肺栓塞的有效指标

目的 比较不同辅助检查在肺栓塞（Pulmonary Embolism,PE）患者的应用价值。方法 回顾诊断和非诊断肺栓塞的患者D二聚体、下肢静脉超声（lower extremity Doppler ultrasound DUS）,胸部螺旋CT（chest spiral Computer Tomography CT）的结果,找出合适敏感度和特异度的方法。结果 D-二聚体是筛除肺栓塞的良好指标,其医学决定性水平宜在500μg／L;临床概率低的患者总体D-二聚体偏高;确诊肺栓塞的患者检查敏感度分别为D-二聚体80％、螺旋CT90%、下肢静脉超声60%;对于低临床概率患者,D-二聚体阴性可以有效除外肺栓塞,漏诊率7．7％。结论 D-二聚体在医学决定性水平为500μg／L时,是一项高敏感度和阴性预计值的指标,尤其适合临床低概率患者的筛除,配合螺旋CT,可以很好地辅助肺栓塞的诊断。     

Family history of venous thromboembolism predicts the diagnosis of acute pulmonary embolism in the emergency department

Background

Pulmonary embolism (PE) clinical decision rules do not consider a patient's family history of venous thromboembolism (VTE). We evaluated whether a family history of VTE predicts acute PE in the emergency department (ED).

Wells评分联合D-dimer在急性肺栓塞诊断的临床预测价值

目的 评价Wells评分联合D-dimer在急性肺栓塞诊断的临床预测价值.方法 收集2008年至2011年就诊北京朝阳医院急诊科疑似肺栓塞患者540例,以CTPA检查阳性为确诊肺栓塞的依据,分为肺栓塞(PE)组与非肺栓塞(Non-PE)组,对两组患者在人口学特征、基础疾病、主诉、体征、静脉血栓危险因素、相关实验室检查、Wells评分等进行比较和统计学分析.结果 最终入选患者502例,PE组246例,Non-PE组256例,近期术后或卧床、近期骨盆或下肢骨折、咯血、一过性意识障碍、单侧下肢肿胀、低氧低碳酸血症、D-dimer升高、高危Wells评分等在PE组出现的频率显著高于Non-PE组,P＜0.05,其他参数在两组中差异无统计学意义.Wells评分、D-dimer值及二者联合的ROC曲线下面积分别是0.775 (95％CI:0.719～0.831),0.802(95％CI:0.751～0.853),0.899 (95％ CI:0.834～0.964),二者联合ROC曲线下面积大于二者单独应用,P ＜0.05.截点值Wells评分5分,D-dimer 1 724.00 μg/L为敏感度与特异度加权最大值,超过截点值时,诊断PE的可靠性明显提高;低于截点值时,排除PE的可靠性也明显升高.结论 Wells评分联合D-Dimer检查比单独应用在急性肺栓塞预测中更具备临床价值.     

D-二聚体测定在肺栓塞诊断中的应用价值

目的 探讨全自动免疫分析系统（VIDAS）快速定量检测D－二聚体（DD）在诊断肺栓塞中的临床价值。方法 使用VIDAS DD测定法对可疑静脉血栓塞患者血浆中纤维蛋白降解产物D－二聚体进行检测，并对这些可疑肺栓塞患者进行3个月的随访，了解是否有肺栓塞或深部静脉栓塞的症状。结果 共有104例患者参加检测，32例患者（30.8%）的D－二聚体检测值＜494ng/ml，72例患者血浆中的D－二聚体检测值＞494ng/ml，其中有16例患者通过肺通气－灌注扫描（V／Q）证实为肺栓塞。VIDAS DD法的敏感性为100％，阴性预期值为100％。结论 VIDAS DD法可作为排除诊断肺栓塞的首选筛选试验，可在临床诊断中推广应用。     

Comparison of the age-adjusted and clinical probability-adjusted D-dimer to exclude pulmonary embolism in the ED

Background

Diagnosing pulmonary embolism (PE) in the emergency department (ED) can be challenging because its signs and symptoms are non-specific.

急性肺栓塞患者应用rt-PA溶栓8例护理体会

目的：总结护理在急性肺栓塞患者应用rt-PA溶栓疗法中的作用。方法：应用rt-PA为急性肺栓塞8例进行溶栓治疗。结果：8例溶栓均获成功。结论：急性肺栓塞早期应用rt-PA溶栓，效果优于其他溶栓药物。溶栓疗法专业性强，护士不但要熟练掌握护理基础理论及技术操作，而且要认识和掌握rt-PA溶栓的要点和操作步骤，加强对病情的监护，促进急性肺栓塞患者早日康复。     

Direct Comparison of the Diagnostic Accuracy of Fifty Protein Biological Markers of Pulmonary Embolism for Use in the Emergency Department

Objectives: Pulmonary embolism (PE) is associated with abnormal concentrations of many proteins involved in inflammation, hemostasis, and vascular injury. The authors quantified the diagnostic accuracy of a battery of protein biological markers for the detection of PE in emergency department (ED) patients. Methods: A random and a consecutive sample of ED patients evaluated for PE were prospectively enrolled at two academic EDs between August 2005 and April 2006. A plasma sample was obtained at enrollment, and all patients were followed by telephone and medical record review at 90 days for the development of venous thromboembolism (VTE) defined as PE or deep venous thrombosis (DVT), requiring the consensus of two of three blinded physician reviewers. Measurements of potential biological markers were performed by technicians blinded to the study objectives. The diagnostic accuracy of each biological marker was determined by the area under the receiver operating characteristic (ROC) curve. Results: Fifty potential biological markers were measured in 304 ED patients, including 22 patients (7%, 95% confidence interval [CI] = 4% to 10%) with VTE. Fourteen biological markers demonstrated an area under the curve (AUC) with the lower limit of the 95% CI ≥ 0.5. Of these, three demonstrated an AUC ≥ 0.7: D‐dimer (0.90), C‐reactive protein (CRP; 0.78), and myeloperoxidase (MPO; 0.78). Conclusions: From 50 candidate biological markers, only D‐dimer, CRP, and MPO demonstrated sufficient diagnostic accuracy to suggest potential utility as biological marker of PE.     

光谱CT肺动脉成像定性诊断肺动脉栓塞及定量评估肺组织灌注

目的 观察光谱CT肺动脉成像(SCTPA)定性诊断肺动脉栓塞(PE)和定量评估肺组织灌注的价值。方法 回顾性分析37例临床诊断PE患者的CTPA资料,观察常规CTPA及SCTPA后处理图像,后者包括40 keV虚拟单能量图(VMI_{40 keV})、碘密度图(IDI)与有效原子序数(Z-eff)图的融合图及电子密度图(EDI);记录2种图像中肺段动脉、肺亚段及以下动脉内的栓子数量和位置,对比其中相应肺灌注缺损区与对侧相应正常肺实质区常规CT值、碘密度(ID)、Z-eff及电子密度(ED)的差异;针对差异有统计学意义的sCTPA参数绘制受试者工作特征(ROC)曲线,计算曲线下面积(AUC),评估其区分PE肺灌注缺损区与正常肺实质的效能。结果 37例中,仅以常规CTPA检出37个栓子,其中26个位于肺段动脉、11 个位于肺亚段及以下动脉;之后结合SCTPA后处理图像额外检出1个肺段动脉和2个肺亚段以下动脉内栓子。全部40个栓子对应肺灌注缺损区常规CT值高于、ID及Z-eff均低于对侧正常肺实质区(P均<0.01),而ED与正常肺实质区差异无统计学意义(P=0.54)。以常规CT值区分肺灌注缺损区与正常肺实质区的敏感度、特异度分别为42.50%及87.50%,以ID及Z-eff区分的敏感度分别为95.00%、97.50%,特异度均为100%。ID及Z-eff的AUC均为0.99,均高于常规CT值(0.65,Z=5.56、5.53,P均<0.01),而 ID与Z-eff的AUC差异无统计学意义(Z=0.71,P=0.48)。结论 利用SCTPA可提高PE检出率及定量评估肺组织灌注;根据ID及Z-eff可有效区分肺灌注缺损区与正常肺实质。     

肺栓塞患者血清同型半胱氨酸和超敏C反应蛋白检测的临床意义

目的探讨肺栓塞(PE)患者血清中同型半胱氨酸(Hcy)和超敏C反应蛋白(hs-CRP)的变化与临床意义。方法测定43例急性肺栓塞患者和42例健康体检者血清的Hcy、hs-CRP浓度并进行统计分析。结果与健康对照组相比,PE组中Hcy和hs-CRP水平明显升高(P<0.01);且血清Hcy水平与hs-CRP水平呈正相关(r=0.621,P<0.01)。结论急性肺栓塞患者血清Hcy和hs-CRP水平的升高呈正相关,联合检测可作为预测急性肺栓塞发生、发展的敏感指标。