Circulatory failure in acute pulmonary embolism

Circulatory failure occurs in about 10% of patients with pulmonary embolism, resulting from a massive obstruction of the pulmonary arterial bed. Hemodynamic and respiratory features are well established; they involve precapillary pulmonary hypertension, low cardiac output state, elevated filling pressure for the right ventricle, and venous admixture. More recently, two-dimensional echocardiography permitted the visualization of pulmonary artery and right heart enlargement, reduced right ventricular ejection fraction, and tricuspid regurgitation. Evaluated by this latter means, left ventricular systolic function appeared unchanged, but diastolic function might be reduced by septal bulging.     

Platelet activation in acute pulmonary embolism

BACKGROUND: Platelet activation is implicated in thrombotic disorders, but has not been described in acute clinical pulmonary embolism (PE). Objectives: To investigate the natural history of platelet activation in PE and associated markers of inflammation, thrombosis and cardiac dysfunction. METHODS: Thirty-five consecutive patients (age 62 +/-17 years) with acute PE were prospectively enrolled and followed for 6 months. Platelet activation was assessed by flow cytometry [measuring expression of platelet P-selectin, conformational activation of glycoprotein IIb/IIIa complex (PAC-1) and formation of platelet-leukocyte complexes] and by plasma soluble P-selectin. Platelet activation, right ventricular (RV) function (assessed as RV ejection area by transthoracic echocardiography), D-dimer and high-sensitivity C-reactive protein (hs-CRP) were measured at presentation and repeated over 6 months follow-up. RESULTS: Soluble P-selectin (56 +/-19 ng mL(-1), anovaP < 0.0001) and PAC-1 (1.5 +/- 1.8%, anovaP = 0.005) were mildly but significantly increased in patients with acute PE relative to healthy young men (soluble P-selectin 33 +/- 13 ng mL(-1), P < 0.001; PAC-1 binding 0.5 +/- 0.6%, P < 0.01) and age-matched controls (soluble P-selectin 31 +/- 9 ng mL(-1), P < 0.001; PAC-1 binding 0.4 +/-0.4%, P < 0.05). Platelet P-selectin expression and platelet-leukocyte complexes were not increased during acute PE. Echocardiographic RV ejection area correlated inversely with soluble P-selectin (r = -0.47, P = 0.007) and positively with platelet P-selectin (r = 0.49, P = 0.0007), suggesting P-selectin is shed from activated platelets in proportion to the severity of RV dysfunction. Elevated soluble P-selectin, D-dimer and hs-CRP demonstrated a time-dependent return to normal during 6 months follow-up. CONCLUSION: Platelet activation is evident after acute PE. Platelet activation correlates with the severity of RV dysfunction, and can persist for several months after acute PE.     

Syncope in acute pulmonary embolism.

BACKGROUND: Syncope is a possible but little known presenting manifestation of acute pulmonary embolism (PE). The importance of syncope at the presentation of acute PE is not known. OBJECTIVES: To report the frequency and to establish the prognostic significance of syncope at the presentation of acute PE. METHODS: A retrospective review of the records of 154 consecutive patients admitted to an Internal Medicine service with acute PE. RESULTS: Fourteen patients with acute PE (9.1%) had syncope at presentation. Epidemiological and clinical characteristics (including respiratory failure, right heart failure and arterial hypotension), and hospital mortality were similar in patients with or without syncope. CONCLUSIONS: Syncope is not an uncommonly presenting manifestation of acute PE. Patients with acute PE and syncope have similar characteristics to those without syncope. Syncope does not seem to determine a poor prognosis.     

Diagnosis of acute pulmonary embolism

Advances in the management of patients with suspected pulmonary embolism (PE) have improved diagnostic accuracy and made management algorithms safer, easier to use, and well standardized. These diagnostic algorithms are mainly based on the assessment of clinical pretest probability, D‐dimer measurement, and imaging tests—predominantly computed tomography pulmonary angiography. These diagnostic algorithms allow safe and cost‐effective diagnosis for most patients with suspected PE. In this review, we summarize signs and symptoms of PE, current existing evidence for PE diagnosis, and focus on the challenge of diagnosing PE in special patient populations, such as pregnant women, or patients with a prior VTE. We also discuss novel imaging tests for PE diagnosis and highlight some of the additional challenges that might require adjustments to current diagnostic strategies, such as the reduced clinical suspicion threshold, resulting in a lower proportion of PE among suspected patients as well as the overdiagnosis of subsegmental PE.     

急性肺栓塞的护理

肺栓塞是指嵌塞物质进入肺动脉及其分支，阻断组织血液供应所引起的病理和临床状态。既往无心肺疾病的患者，呼吸困难是肺栓塞最常见的症状（发生率80％左右），呼吸急促，呼吸频率〉20／min是最常见的体征，尤以活动时最明显。通常，呼吸困难、晕厥或发绀预示有致命性危险。肺栓塞后可导致肺梗死、急性肺原性心脏病。发病率高，     

中危（次大面积）急性肺栓塞患者是否需要溶栓治疗

中危（次大面积）急性肺栓塞患者是否需要溶栓治疗已经争论了很多年。中危肺栓塞患者具有较高的死亡风险。因此,有人建议给予中危肺栓塞患者溶栓治疗,溶栓治疗可以更快地溶解血栓,从而降低中危肺栓塞患者的病死率。但也有研究表明,与单纯抗凝治疗比较,溶栓治疗不能进一步降低中危急性肺栓塞患者的病死率和复发率,且并发出血率较高。该文就中危急性肺栓塞溶栓治疗的有效性及安全性作一综述。     

急性肺栓塞CT肺动脉成像的研究进展

目前,CT肺动脉成像（CTPA）被认为是临床诊断急性肺栓塞（PE）的“金标准”。CTPA为诊断急性外周性PE提供了多方面的依据。但CTPA诊断急性外周性PE仍存在较大困难。目前CT辐射剂量及对比剂负荷为研究热点。本文对急性PE的CTPA诊断（尤其是外周性PE）、预后评估、CTPA技术进展等进行综述。     

B-type natriuretic peptide in acute pulmonary embolism

Myocardial stretch leads to the natriuretic peptides release in acute or chronic left ventricular dysfunction. However, there is an accumulating evidence that B-type natriuretic peptide (BNP) and its N-terminal fragment (NT-proBNP) may originate from right ventricle and their concentrations are elevated in patients with acute pulmonary embolism (APE) especially when resulting in right ventricular dysfunction (RVD). Recently it is underlined that severity assessment of APE as well as the risk stratification and therapy selection is based both on patients' hemodynamic status and markers of myocardial injury and RVD. BNP and NT-proBNP are helpful in identifying patients with RVD in APE, emerging as an adjunctive tool to echocardiography. Elevated BNP or NT-proBNP levels are also significant predictors of death and/or complicated clinical course in APE.     

慢性阻塞性肺疾病急性加重期伴肺动脉栓塞的危险因素分析

目的探讨慢性阻塞性肺疾病急性加重期(AECOPD)伴肺动脉栓塞(PE)的危险因素。方法选取因AECOPD住院且行螺旋CT肺动脉造影(CTPA)检查的患者466例,据CTPA是否出现PE或充盈缺损,将患者分为PE组45例和对照组421例,比较2组临床资料,分析AECOPD合并PE的危险因素。结果 2组年龄≥70岁、卧床≥3 d、下肢水肿、肺炎、静脉血栓、动脉栓塞、D-二聚体≥2 000 ng/m L和N末端脑钠肽前体(NT-pro BNP)≥1 200 ng/m L差异显著(P0.05或P0.01)。多因素Logistic回归分析示,卧床时间≥3 d、下肢水肿、D-二聚体≥2 000 ng/m L为AECOPD伴发PE的危险因素。结论因AECOPD住院的患者,有卧床3 d以上、下肢水肿或D-二聚体≥2 000 ng/m L,应高度重视,尽快行CTPA,以确定是否伴发PE。     

慢性阻塞性肺疾病急性加重合并肺栓塞血液相关风险因素分析

目的分析慢性阻塞性肺疾病(COPD)急性加重(AECOPD)合并急性肺栓塞血液相关风险因素及其相关性分析,为发病机制研究、治疗提供参考。方法纳入2015年5月至2016年4月入院的AECOPD可疑肺栓塞患者73例,检测其血常规、C反应蛋白(CRP)、白细胞介素-8(IL-8)、红细胞沉降率(ESR)、降钙素原(PCT)、内皮素-1(ET-1)、D-二聚体、纤维蛋白原、心肌酶、动脉血气、乳酸脱氢酶(LDH)等指标,并进行胸部肺动脉造影(CTPA)检查,分析AECOPD合并肺栓塞患者与未合并肺栓塞患者血液相关风险因素的关系。结果 73例患者中,有15例为AECOPD合并肺栓塞,58例为AECOPD未合并肺栓塞。AECOPD合并肺栓塞患者的Neu%、PCT、NT-proBNP、D-二聚体、LDH、cTnI、CRP、IL-8、ET-1水平整体高于未合并肺栓塞患者(P0.05)。AECOPD合并肺栓塞患者血CRP与IL-8相关系数为0.457(P=0.087),与ET-1相关系数为0.598(P=0.019),IL-8与ET-1相关系数为0.695(P=0.004)。结论 AECOPD合并肺栓塞与体内炎症严重程度相关,炎性反应越重,对心肌损伤也相应增加,发生肺栓塞的风险增加。     

Computed tomography of acute pulmonary embolism

Pulmonary embolism (PE) is a common condition in which diagnostic and therapeutic delays contribute to substantial morbidity and mortality. Advances in spiral computed tomography (CT) scanner technology over the past 10 years have been paralleled by progressive improvement in the ability to identify and accurately evaluate the pulmonary arteries for acute PE using CT pulmonary angiography (CTPA). Preliminary studies indicate multi-detector CT (MDCT) scanners offer improved accuracy for distal segmental and subsegmental PE. The ability to directly visualize emboli using CTPA has led to its widespread implementation. Published studies using optimal techniques have found sensitivity and specificity of approximately 90%. Clinical signs and symptoms are nonspecific. Only 20% to 30% of those patients evaluated for acute PE are found to harbor emboli. Previous imaging algorithms offered limited diagnostic value for the remaining 70% to 80% of patients who proved not to have PE. It has been shown that spiral CT identifies an alternate diagnosis in approximately 70% of these patients, which, along with its rapid and widespread availability, largely accounts for its popularity with referring clinicians. It is noted that meta-analysis studies of the existing data regarding spiral CT in acute PE have shown deficiencies in study designs, indicating that further research is required. However, at this time, spiral CT is being widely employed in the diagnostic work-up of patients with suspected acute PE. This review will discuss the use of spiral CT for acute PE, including scan acquisition parameters, radiation dose, diagnostic findings, interpretive pitfalls and the role of leg vein studies.     

Imaging diagnosis of acute pulmonary embolism

Pulmonary embolism represents a major public healthcare problem and it also imposes frequent clinical diagnostic issues. Despite the availability of the D-dimer tests, imaging remains the mainstay for its diagnosis. Computed tomography pulmonary angiography (CTPA) is now the most widely used diagnostic test and its utility has been well validated in a large number of trials. Nuclear medicine techniques, which are also well established, are now used significantly less frequently. Magnetic resonance pulmonary angiography is developing as an alternative to CTPA in patients who have contraindications to iodinated contrast media. Catheter pulmonary angiography remains the gold standard, although it is being used increasingly less frequently. In this article, we review the current knowledge on the imaging diagnosis of acute pulmonary embolism with special emphasis on the noninvasive techniques.     

Therapeutic approach to acute pulmonary embolism

Many therapeutic aspects of venous thromboembolism continue to generate controversy so that the general therapeutic guidelines given below are only indicative. The first step is the diagnosis of venous thromboembolism; this is done in the vast majority of patients by visualization of blood clots using either pulmonary angiography or phlebography. The second step is to arrest the thrombotic process; the best means of doing this is to administer IV heparin. In the case of contra-indication or documented inefficacy of heparin therapy, the only therapeutic solution is to interrupt the inferior vena cava either with a clip, an umbrella or a filter. The blood clot lysis, which represents the third step, is effected by the natural fibrinolytic system. Thrombolytics, administered as a bolus of urokinase (15000 CTA U/kg), are indicated in cases of life-threatening pulmonary emboli, i.e. those with a pulmonary vascular obstruction of more than 50% and with hypotension, shock, or acute right ventricular failure. The use of thrombolytics is more questionable when they are administered to improve the quality of vascular patency. The only indication for pulmonary embolectomy is a contra-indication or inefficacy of thrombolytics. Due to the diagnostic and therapeutic difficulties, the first and most important part of the treatment of pulmonary emboli must be the broad application of prophylaxis treatment in patients with a high risk of venous thromboembolism.     

心脏型脂肪酸结合蛋白在急性肺栓塞危险分层中的临床价值

心脏型脂肪酸结合蛋白(H-FABP)是一种敏感性极高的早期心肌损伤标记物,已被论证可用于急性冠脉综合征的诊断和风险评估.本文综述了近年来H-FABP应用于急性肺栓塞(APE)危险分层的临床前瞻性试验并得出结论,H-FABP可以应用于肺栓塞的危险分层,特别对于非高危组肺栓塞患者,H-FABP与肺栓塞患者预后,不管是短期预后还是长期预后都有着很好的相关性.     

Imaging diagnosis of acute pulmonary embolism

Pulmonary embolism represents a major public healthcare problem and it also imposes frequent clinical diagnostic issues. Despite the availability of the D-dimer tests, imaging remains the mainstay for its diagnosis. Computed tomography pulmonary angiography (CTPA) is now the most widely used diagnostic test and its utility has been well validated in a large number of trials. Nuclear medicine techniques, which are also well established, are now used significantly less frequently. Magnetic resonance pulmonary angiography is developing as an alternative to CTPA in patients who have contraindications to iodinated contrast media. Catheter pulmonary angiography remains the gold standard, although it is being used increasingly less frequently. In this article, we review the current knowledge on the imaging diagnosis of acute pulmonary embolism with special emphasis on the noninvasive techniques.     

Endovascular interventions for acute pulmonary embolism

Massive pulmonary embolism (PE) is a highly lethal condition with clinical manifestations of hemodynamic instability, acute right ventricular (RV) failure, and cardiogenic shock. Submassive PE, as defined by RV failure or troponin elevation, can result in life-threatening sequelae if treatment is not initiated promptly. Current treatment paradigm in patients with massive PE mandates prompt risk stratification with aggressive therapeutic strategies. With the advent of endovascular technologies, various catheter-based thrombectomy and thrombolytic devices are available to treat patients with massive or submassive PE. In this article, a variety of endovascular treatment strategies for PE are analyzed. The authors' institutional experience with ultrasound-accelerated thrombolytic therapy as well as catheter-directed thrombolytic therapy in patients with acute massive PE during a recent 10-year period is discussed. Finally, clinical evidence on the utilization of catheter-based interventions in patients with massive and submassive PE is also analyzed.     

Experience with streptokinase treatment of major pulmonary embolism

The efficacy of streptokinase was studied in an open trial on 30 consecutive patients with major pulmonary embolism, affecting at least three lobar arteries in pulmonary angiography. Streptokinase was started on average 26 hours from the onset of symptoms and usually given directly to the pulmonary artery. Conventional dosage was used and adjusted by thrombin time. The average treatment period was 32 hours. 26 patients (87%) survived and made a good clinical recovery. Improvement occurred early: signs of improved pulmonary perfusion appeared usually within four hours. Repeat angiograms in 20 patients showed remarkable increase in pulmonary perfusion and partial but not complete lysis of the emboli. Four patients (13%) died, three of them because of no response and one due to late cardiac arrhythmia. Bleeding requiring blood transfusion occurred in four patients, but caused no late sequelae. It is concluded that streptokinase treatment of major pulmonary embolism is effective and safe in rapidly restoring pulmonary perfusion.