Diagnosis and treatment of subsegmental pulmonary embolism

Subsegmental pulmonary embolism (SSPE) affects the 4th division and more distal pulmonary arterial branches. SSPE can be isolated or affect multiple subsegments, be symptomatic or incidental (unsuspected) and may or may not be associated with deep vein thrombosis. Symptoms, clinical risk scores and biomarkers are less sensitive for diagnosing SSPE compared to more central pulmonary embolism. The diagnosis is confirmed using radiological imaging, predominately computed tomographic pulmonary angiogram (CTPA) or ventilation/perfusion scanning. The increasing utilization of CTPAs may have resulted in overdiagnosis driven by smaller pulmonary emboli. There is insufficient evidence of improved mortality or reduced venous thromboembolism recurrence with anticoagulation treatment for SSPE however, the major and clinically significant haemorrhage risks are well described. As the resolution of diagnostic imaging has improved, we may be viewing the natural physiological filtering process performed by the lungs that may not require treatment.     

Anticoagulant treatment of pulmonary embolism: impact and implications of the EINSTEIN PE study

Pulmonary embolism (PE), which can develop as a consequence of deep vein thrombosis (DVT), is a serious and potentially fatal venous thromboembolic event. Patients with PE are at increased risk of venous thromboembolism (VTE) recurrence and serious complications such as chronic thromboembolic pulmonary hypertension. Anticoagulants, namely heparins and vitamin K antagonists (VKAs), have been the main treatments for PE in patients who are haemodynamically stable. However, use of these agents can be complex and is associated with an increased risk of bleeding (a characteristic that is common to all anticoagulants). Simplified, effective treatment regimens for PE would be very beneficial for patients, physicians and payers. Compared with DVT, PE is a different clinical manifestation of VTE; phase III trials have now started to focus specifically on patients with PE. Trials in patients with PE can provide further information on the optimal management of these patients. Results of the phase III EINSTEIN PE study demonstrated non-inferiority in the efficacy and safety of oral rivaroxaban compared with standard of care (enoxaparin/VKA) for the treatment of patients with acute symptomatic PE (with or without symptomatic DVT). Rates of major bleeding were significantly lower in patients receiving rivaroxaban. This review will discuss the findings of recent trials, particularly the potential impact of single, oral agents for both the initial and long-term treatment of a range of patients with PE, and how these results may influence the clinical management of PE.     

Recent developments in the diagnosis and treatment of pulmonary embolism

Due to the nonspecific symptoms of the condition, a diagnosis of acute pulmonary embolism (PE) is frequently considered. However, PE will only be confirmed in 10–20% of patients. Because the imaging test of choice, computed tomography pulmonary angiography (CTPA), is costly and associated with radiation exposure and other complications, a validated diagnostic algorithm consisting of a clinical decision rule and D‐dimer test should be used to safely exclude PE in 20–30% of patients without the need for CTPA. Recently, the age‐adjusted D‐dimer threshold has been validated, and this has increased the proportion of patients at older age in whom PE can be excluded without CTPA. Initial therapeutic management of PE depends on the risk of short‐term PE‐related mortality. Haemodynamically unstable patients should be closely monitored and receive thrombolytic therapy unless contraindicated because of an unacceptably high bleeding risk, whereas patients with low‐risk PE may be safely discharged early from hospital or receive only outpatient treatment. The PESI score and Hestia decision rule are available to select patients in whom early discharge or outpatient treatment will be safe, although the safety of these strategies should be confirmed in additional studies. Standard PE therapy consists of low molecular weight heparin (LMWH) followed by vitamin K antagonists (VKAs). Recently, several nonvitamin K‐dependent oral anticoagulants have been shown to be as effective as LMWH/VKAs, and maybe safer. Determining the optimal duration of treatment for a first unprovoked PE remains a challenge, although clinical prediction rules for estimating the risk of recurrence of venous thromboembolism and anticoagulation‐associated haemorrhage are under investigation. Using these prediction rules may lead to both more standardized and more individualized long‐term treatment of PE.     

Update on the diagnosis and management of pulmonary embolism

Pulmonary embolism (PE) is a common and often fatal disease. In the US, an estimated 40-53 people per 100,000 are diagnosed with PE annually and approximately 60,000 die from the disease. Diagnosis is difficult because symptoms are non-specific; however, a quick and accurate diagnosis is critical because, with appropriate therapy, the risk of recurrent (and potentially fatal) PE can be greatly reduced. Recent publication of prediction rules and improved non-invasive diagnostic tools have simplified diagnostic algorithms for PE. The efficacy of the standard treatment for PE, initial administration of continuous i.v. unfractionated heparin overlapped with long-term oral anticoagulation, is well established. However, newer treatment options such as low-molecular-weight heparins and the pentasaccharides may offer similar efficacy with improved convenience.     

Withholding anticoagulation after a negative computed tomography pulmonary angiogram as a stand-alone imaging investigation: a prospective management study

Background: Accurate diagnosis of pulmonary embolism (PE) is essential and it is not clear whether a computed tomography pulmonary angiogram (CTPA) could be used as a stand‐alone imaging investigation. The aim of the study was to test the accuracy of the clinical outcome of a negative CTPA as a stand‐alone imaging investigation to exclude PE. Methods: Five hundred and thirty‐four consecutive patients who had a CTPA for diagnosis or exclusion of PE were recruited from March 2003 to October 2004. Four hundred and ninety‐four patients had a helical CTPA as a stand‐alone imaging investigation for diagnosis or exclusion of PE. A 3‐month post‐CTPA follow up was carried out in all patients to establish the clinical outcome accuracy of a negative CTPA as a stand‐alone imaging investigation. Results: There were 387 (78.3%) negative and 107 (21.7%) positive CTPA examinations. The average age of the patients was 57.16 years (standard deviation 18.57). Among those with a negative CTPA who survived, one patient had deep vein thrombosis and 342 patients had no evidence of an episode of venous thromboembolism or PE at the 3‐month follow up. Thirty‐eight patients died within the 3‐month follow‐up period and one patient’s death was attributed to suspected PE. The negative predictive value of a CTPA is 99.5% (95% confidence interval 98.1–99.9%). Conclusion: Helical negative CTPA examination excludes clinically significant PE as a stand‐alone imaging investigation. Where concurrent deep vein thrombosis is suspected, lower limb needs to be imaged by ultrasound if the CTPA is negative.     

Septic pulmonary embolism due to periodontal disease

Background and objective: Septic pulmonary embolism due to periodontal disease (SPE‐PD) is rarely reported and little is known about its clinical features. The purpose of this study was to evaluate the clinical and radiological features, as well as outcome, in SPE‐PD. Methods: Patients' records were retrospectively reviewed and 12 patients with SPE‐PD were identified (10 men, mean age 60.5 years). The patients' demographic features, laboratory data, physical and radiological findings, and clinical outcomes were evaluated. Results: All but one patient were smokers. Eight of the 12 patients had comorbidities including hypertension (58%) and/or diabetes mellitus (17%). Prevalent symptoms were fever (67%) and chest pain (58%). Only two patients fulfilled the criteria of systemic inflammatory response syndrome; most of the subjects were not clinically severely ill. Blood cultures were negative in all cases. Contrast‐enhanced chest computed tomography (CT) showed multiple peripheral nodules in all 12 patients, wedge‐shaped peripheral lesions abutting on the pleura in 10 (83%) and a feeding‐vessel sign in 9 (75%). All patients recovered from their illness after antimicrobial therapy concomitant with tooth extraction or periodontal care. The median duration of antibiotic administration was 51 days. Conclusions: Most patients with SPE‐PD were not seriously ill. Contrast‐enhanced chest CT appeared to be useful to diagnose SPE‐PD.     

肺动脉栓塞的多层螺旋CT诊断与鉴别

目的研究肺动脉栓塞多层螺旋CT肺血管成像的影像表现,探讨与肺动脉栓塞表现相似疾病的鉴别,提高肺动脉栓塞诊断与鉴别诊断的水平。方法对21例肺动脉栓塞（1例为瘤栓）患者行多层螺旋CT肺动脉成像检查,图像采用10mm层厚,10mm层间距,和1．25层厚,0．625mm层间距进行重建,所获的数据传送至工作站运用MPR、MIP、VR技术后处理。结果20例中（不包括1例肺动脉肿瘤）,双侧肺动脉受累18例,单侧2例,病变累及131支肺动脉及分支。其中发生于左及右肺动脉远端18支,肺叶动脉38支、肺段动脉50支、肺段以下25支,CT显示的直接征象为肺动脉及分支血管内不同程度的充盈缺损,增强扫描不强化。充盈缺损依形态可分为4种：中心型（25支）、偏心型（61支）、附壁型（25支）、完全闭塞型（20支）。并存间接征象为主肺动脉及左右肺动脉增宽,局限性肺内灌注不均匀,肺梗死,胸腔积液及右房、右室增大。结论肺动脉栓塞在CT图像上形态多样,病变范围广泛,双侧发病多于单侧,主肺动脉受累少见。多层螺旋CT肺血管成像对本病的诊断有独特的优势,该方法能清晰显示肺动脉栓塞的直接征象和间接征象。为诊断及鉴别诊断提供可靠的影像学资料。     

Diagnostic yield of CT pulmonary angiography for pulmonary embolism in clinically suspected patients

Pulmonary embolism (PE) is a common medical problem. Its diagnostic criteria must be reviewed to determine the need for confirmatory testing. Computed tomography pulmonary angiography (CTPA) is the current standard of care, which provides accurate diagnosis with rapid turnaround. This study aimed to estimate the diagnostic yield of CTPA in clinically suspected PE patients in a tertiary care hospital in Saudi Arabia.Radiology records of all patients with clinically suspected PE who underwent CTPA between January 1, 2012 and September 30, 2018 were reviewed retrospectively. A radiologist with 10 years of professional experience interpreted and reported all cases. The Wells score with 2 tiers (likely and unlikely) was used to raise the clinical suspicion of PE.Positive results for PE were reported in 177 out of 534 clinically suspected cases (33%). Among the positive PE cases, 143 were acute (81%) and 34 (19%) were chronic. Bilateral, right-sided, and left-sided PE were found in 115 (65%), 37 (21%), and 25 (14%) cases, respectively. Involvement of the segmental branches, subsegmental branches, and the pulmonary trunk were noted in 152 (86%), 70 (40%), and 9 cases (5%), respectively. Saddle PE was found in (4%) of the cases. The lower lobe branches (right 55%, left 53%) and the upper lobe branches (right 47%, left 41%) were the most common sites of involvement.CTPA had a higher positive detection rate for PE among clinically suspected cases than its published diagnostic yield. Adequate clinical evaluation when selecting patients for CTPA is emphasized to minimize unjustified exposure of the patients to radiation and intravenous contrast administration. It is crucial for radiologists to provide detailed reports commenting on all relevant findings, including pertinent negatives. A template for reporting radiological findings for CTPA can be recommended for this purpose.     

老年肺栓塞的螺旋CT肺动脉造影诊断研究

目的探讨螺旋CT肺动脉造影在老年肺动脉栓塞(PE)诊断中的临床应用价值。方法采用螺旋CT对66例老年PE患者行肺动脉增强扫描,其中多层、单层螺旋CT(MSCT,SCT)肺动脉造影检查者各为21和45例。结果分析66例老年PE患者的2728支肺动脉,MSCT、SCT肺动脉造影共显示926支肺动脉受累。直接征象为中心型充盈缺损、部分型充盈缺损、完全性阻塞、附壁性充盈缺损,约占33.9%;1206支段以上肺动脉中,依据直接征象MSCT、SCT分别检出240支/384支(62.5%)和481支/822支(58.5%),共721支/1206支,两者检出率无明显差别(P=0.037);1522支亚段肺动脉中,MSCT、SCT分别检出121支/484支(25.0%)和84支/1038支(8.1%),共205支/1522支,前者检出率明显高于后者(P=0.632)。平扫示间接征象共125例次。结论MSCT、SCT对段以上PE的诊断二者均有较高的准确度,MSCT对亚段PE的诊断有其优势。     

Clinical characteristics of patients with acute pulmonary embolism: data from PIOPED II

Background

Selection of patients for diagnostic tests for acute pulmonary embolism requires recognition of the possibility of pulmonary embolism on the basis of the clinical characteristics. Patients in the Prospective Investigation of Pulmonary Embolism Diagnosis II had a broad spectrum of severity, which permits an evaluation of the subtle characteristics of mild pulmonary embolism and the characteristics of severe pulmonary embolism.

Methods

Data are from the national collaborative study, Prospective Investigation of Pulmonary Embolism Diagnosis II.

Results

There may be dyspnea only on exertion. The onset of dyspnea is usually, but not always, rapid. Orthopnea may occur. In patients with pulmonary embolism in the main or lobar pulmonary arteries, dyspnea or tachypnea occurred in 92%, but the largest pulmonary embolism was in the segmental pulmonary arteries in only 65%. In general, signs and symptoms were similar in elderly and younger patients, but dyspnea or tachypnea was less frequent in elderly patients with no previous cardiopulmonary disease. Dyspnea may be absent even in patients with circulatory collapse. Patients with a low-probability objective clinical assessment sometimes had pulmonary embolism, even in proximal vessels.

Conclusion

Symptoms may be mild, and generally recognized symptoms may be absent, particularly in patients with pulmonary embolism only in the segmental pulmonary branches, but they may be absent even with severe pulmonary embolism. A high or intermediate-probability objective clinical assessment suggests the need for diagnostic studies, but a low-probability objective clinical assessment does not exclude the diagnosis. Maintenance of a high level of suspicion is critical.     

320层CT单容积肺动脉成像诊断老年肺动脉血栓栓塞的临床应用

目的探讨320层CT单容积肺动脉成像诊断肺动脉血栓栓塞(肺栓塞)的临床应用价值。方法应用320层CT单容积扫描模式对75例年龄60岁临床怀疑肺栓塞患者行肺动脉CT成像,采用容积再现技术、多平面重建及曲面重建等方法分析扫描数据。结果本组75例患者均成功完成扫描,图像质量均可满足诊断,41例诊断为肺栓塞,其中段级肺栓塞12例,余34例除外肺栓塞。全部病例最终诊断均经核素肺通气灌注扫描及临床溶栓治疗有效所证实。应用320层CT单容积肺动脉成像扫描时间1 s,平均射线剂量为(2.73±0.47)mSv,造影剂总量45 ml。结论 320层CT单容积肺动脉成像诊断肺栓塞是一种有效的无创检查手段,其具有低射线损伤、低对比剂用量、成像速度快等优势,尤其适用于临床急重症及老年患者。