Prognostic clinical prediction rules to identify a low‐risk pulmonary embolism: a systematic review and meta‐analysis

Summary. Background: Prognostic assessment is important for the management of patients with a pulmonary embolism (PE). A number of clinical prediction rules (CPRs) have been proposed for stratifying PE mortality risk. The aim of this systematic review was to assess the performance of prognostic CPRs in identifying a low‐risk PE. Methods: MEDLINE and EMBASE databases were systematically searched until August 2011. Derivation and validation studies that assessed the performance of prognostic CPRs in predicting adverse events‐risk in PE patients were included. Weighted mean proportion and 95% confidence intervals (CIs) of adverse events were then calculated and pooled using a fixed and a random‐effects model. Statistical heterogeneity was evaluated through the use of I² statistics. Results: Of 1125 references in the original search, 33 relevant articles were included. Nine CPRs were assessed in 37 cohorts, for a total of 35 518 patients. Pulmonary Embolism Severity Index and prognostic Geneva CPR were investigated in 22 and 6 cohorts, respectively. Eleven (29.7%) cohorts were of high quality. The median follow‐up was 30 days. In low‐risk PE patients, pooled short‐term mortality (within 14 days or less) was 0.7% (95% CI 0.3–1.1%, random‐effects model; I² = 49.6%), 30‐day mortality was 1.7% (95% CI 1.1–2.3%, random‐effects model; I² = 82.4%) and 90‐day mortality was 2.2% (95% CI 1.2–3.4%, random‐effects model; I² = 59.8%). Conclusions: Prognostic CPRs efficiently identify PE patients at a low risk of mortality. Before implementing prognostic CPRs in the routine care of PE patients, well‐designed management studies are warranted.     

Clinical prediction rules for pulmonary embolism: a systematic review and meta‐analysis

Summary. Background: Pretest probability assessment is necessary to identify patients in whom pulmonary embolism (PE) can be safely ruled out by a negative D‐dimer without further investigations. Objective:   Review and compare the performance of available clinical prediction rules (CPRs) for PE probability assessment. Patients/methods: We identified studies that evaluated a CPR in patients with suspected PE from Embase, Medline and the Cochrane database. We determined the 95% confidence intervals (CIs) of prevalence of PE in the various clinical probability categories of each CPR. Statistical heterogeneity was tested. Results: We identified 9 CPR and included 29 studies representing 31215 patients. Pooled prevalence of PE for three‐level scores (low, intermediate or high clinical probability) was: low, 6% (95% CI, 4–8), intermediate, 23% (95% CI, 18–28) and high, 49% (95% CI, 43–56) for the Wells score; low, 13% (95% CI, 8–19), intermediate, 35% (95% CI, 31–38) and high, 71% (95% CI, 50–89) for the Geneva score; low, 9% (95% CI, 8–11), intermediate, 26% (95% CI, 24–28) and high, 76% (95% CI, 69–82) for the revised Geneva score. Pooled prevalence for two‐level scores (PE likely or PE unlikely) was 8% (95% CI,6–11) and 34% (95% CI,29–40) for the Wells score, and 6% (95% CI, 3–9) and 23% (95% CI, 11–36) for the Charlotte rule. Conclusion: Available CPR for assessing clinical probability of PE show similar accuracy. Existing scores are, however, not equivalent and the choice among various prediction rules and classification schemes (three‐ versus two‐level) must be guided by local prevalence of PE, type of patients considered (outpatients or inpatients) and type of D‐dimer assay applied.     

Diagnostic management of clinically suspected acute pulmonary embolism

Summary.  Current diagnostic management of hemodynamically stable patients with clinically suspected acute pulmonary embolism (PE) consists of the accurate and rapid distinction between the approximate 20–25% of patients who have acute PE and require anticoagulant treatment, and the overall majority of patients who do not have the disease in question. Clinical outcome studies have demonstrated that, using algorithms with sequential diagnostic tests, PE can be safely ruled out in patients with a clinical probability indicating PE to be unlikely and a normal D-dimer test result. This obviates the need for additional radiological imaging tests in 20–40% of patients. CT pulmonary angiography (CTPA) has become the first line tool to confirm or exclude the diagnosis of PE in patients with a likely probability of PE or an elevated D-dimer blood concentration. While single-row-detector technology CTPA has a low sensitivity for PE and bilateral compression ultrasound (CUS) of the lower limbs is considered necessary to rule out PE, multi-row-detector CTPA is safe to exclude PE without the confirmatory use of CUS.     

The pulmonary embolism rule‐out criteria (PERC) rule does not safely exclude pulmonary embolism

Summary. Background: The Pulmonary Embolism Rule‐out Criteria (PERC) rule is a clinical diagnostic rule designed to exclude pulmonary embolism (PE) without further testing. We sought to externally validate the diagnostic performance of the PERC rule alone and combined with clinical probability assessment based on the revised Geneva score. Methods: The PERC rule was applied retrospectively to consecutive patients who presented with a clinical suspicion of PE to six emergency departments, and who were enrolled in a randomized trial of PE diagnosis. Patients who met all eight PERC criteria [PERC_(?)] were considered to be at a very low risk for PE. We calculated the prevalence of PE among PERC_(?) patients according to their clinical pretest probability of PE. We estimated the negative likelihood ratio of the PERC rule to predict PE. Results: Among 1675 patients, the prevalence of PE was 21.3%. Overall, 13.2% of patients were PERC_(?). The prevalence of PE was 5.4% [95% confidence interval (CI): 3.1–9.3%] among PERC_(?) patients overall and 6.4% (95% CI: 3.7–10.8%) among those PERC_(?) patients with a low clinical pretest probability of PE. The PERC rule had a negative likelihood ratio of 0.70 (95% CI: 0.67–0.73) for predicting PE overall, and 0.63 (95% CI: 0.38–1.06) in low‐risk patients. Conclusions: Our results suggest that the PERC rule alone or even when combined with the revised Geneva score cannot safely identify very low risk patients in whom PE can be ruled out without additional testing, at least in populations with a relatively high prevalence of PE.     

Performance of age‐adjusted D‐dimer cut‐off to rule out pulmonary embolism

Summary: Background: Age‐adjusted D‐dimer cut‐off has recently been proposed to increase D‐dimer usefulness in older patients suspected of pulmonary embolism (PE). Objective: We externally validated this age‐adjusted D‐dimer cut‐off using different D‐dimer assays in a multicenter sample of emergency department patients. Methods: Secondary analysis of three prospectively collected databases (two European, one American) of patients suspected of having PE. D‐dimer performance for ruling out PE was assessed by calculating negative likelihood ratio (nLR) for D‐dimer with age‐adjusted D‐dimer cut‐off (< age × 10 in patients over 50 years) and with conventional cut‐off (< 500 μg dL^?1). Test efficiency was assessed by the number needed to test (NNT) to rule out PE in one patient. Results: Among 4537 patients included, overall PE prevalence was 10.1%. In the overall population, nLR was 0.06 (95% confidence interval, 0.03–0.09) with conventional cut‐off and 0.08 (0.05–0.12) with age‐adjusted cut‐off. Using age‐adjusted cut‐off, nLR was 0.08, 0.09 and 0.06 for Vidas^®, Liatest^® and MDA^® assays, respectively. Use of age‐adjusted cut‐off produced a favorable effect on NNT in the elderly; the greatest decrease was observed in patients > 75 years: NTT halved from 8.1 to 3.6. The proportion of patients over 75 years with normal D‐dimer was doubled (27.9% vs. 12.3%). Conclusions: Our study shows that age‐adjusted D‐dimer had low nLR, allowing its use as a rule‐out PE strategy in non‐high pretest clinical probability patients, as well as using Vidas^®, Liatest^® or MDA^® assays. This age‐adjusted cut‐off increased clinical usefulness of D‐dimer in older patients. A large prospective study is required to confirm these results.     

Differences in clinical presentation of pulmonary embolism in women and men

Summary. Background: The risk of recurrence of pulmonary embolism (PE) is higher in men than in women. Differences in clinical presentation of deep vein thrombosis (DVT) have been reported between the two genders but comparative data on PE are lacking. Objectives:  To compare clinical characteristics between women and men with suspected and confirmed PE and their impact on clinical probability prediction scores and on diagnostic work‐up of PE, and to assess whether differences at presentation could account for the increased recurrence rate in men. Methods:  Combined data from three prospective cohort studies including a total of 3414 outpatients with suspected PE were analyzed retrospectively. Clinical characteristics, pretest probability of PE, diagnostic yield of non‐invasive tests and VTE recurrence rate were compared between genders. Results:  The overall prevalence of PE was similar among women and men (22.3% vs. 23.1%; P = 0.55). The clinical probability prediction scores (Geneva score and Wells score) performed equally well in both genders. A non‐invasive diagnostic work‐up was possible more often in men than in women. The proportion of PE‐associated proximal DVT was higher in men than in women (43% vs. 33%; P = 0.009). VTE recurrence rate was also higher in men than women with PE (5.0% vs. 2.3%; P = 0.045). Conclusion:  In spite of some differences in the clinical presentation of PE between women and men, clinical probability prediction scores perform equally in both genders. A higher prevalence of PE‐associated proximal DVT in men could possibly indicate greater severity of PE episodes and partly account for the higher VTE recurrence rate in men.     

急性肺栓塞的影像诊断与介入治疗分析

目的:对影像诊断急性肺栓塞的应用价值以及介入治疗的效果展开研究。方法:从2017年5月-2019年5月我院收治的患者中随机拣选17例怀疑为急性肺栓塞的患者,所有患者均采取CT诊断,并接受介入治疗,观察CT诊断的准确率以及漏诊和误诊率,此外对比治疗前后的治疗效果。结果:肺动脉造影检查后准确率为100%,CT诊断后准确率94.8%,差异不显著,P>0.05。介入治疗后患者的疼痛评分明显降低,呼吸频率恢复正常,治疗前后差异显著,P<0.05。结论:急性肺栓塞疾病采取CT影响诊断后具有较高的诊断准确率,漏诊率以及误诊率较低,并且在介入治疗后能够有效改善疼痛反应以及各项临床指标,治疗价值较高。     

Non-invasive diagnostic work-up of patients with clinically suspected pulmonary embolism; results of a management study.

BACKGROUND: Clinicians often deviate from the recommended algorithm for the diagnosis of pulmonary embolism consisting of ventilation-perfusion scintigraphy and pulmonary angiography. OBJECTIVES: To assess the safety and feasibility of a diagnostic algorithm which reduces the need for lung scintigraphy and avoids the use of angiography. PATIENTS AND METHODS: Consecutive patients with a clinical suspicion of pulmonary embolism were prospectively investigated according to an algorithm in which the diagnosis of pulmonary embolism was excluded after a low clinical probability estimate and a normal d-dimer test result, a normal perfusion scintigraphy result, or a non-high probability scintigraphy result in combination with normal serial ultrasonography of the legs. In these patients anticoagulant treatment was withheld and they were followed up for 3 months to record possible thromboembolic events. During the study period, 923 consecutive patients were seen, of whom 292 were excluded because of predefined criteria. RESULTS: Of the 631 included patients, the diagnosis was refuted on the basis of a low clinical probability estimate and a normal d-dimer test result (95 patients), normal perfusion scintigraphy (161 patients) and non-high probability lung scintigraphy followed by normal serial ultrasonography (210 patients). Of these 466 patients, venous thromboembolic complications during follow-up occurred in six (complication rate 1.3%, 95% confidence interval 0.5, 2.8). The diagnostic protocol was completed in 92% of all included patients. CONCLUSION: The diagnosis of pulmonary embolism can be safely ruled out by a non-invasive algorithm consisting of d-dimer testing combined with a clinical probability estimate, lung scintigraphy, or serial ultrasonography of the legs (in case of non-diagnostic lung scintigraphy).     

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.     

Comparison of the revised Geneva score with the Wells rule for assessing clinical probability of pulmonary embolism.

BACKGROUND: The revised Geneva score, a standardized clinical decision rule in the diagnosis of pulmonary embolism (PE), was recently developed. The Wells clinical decision is widely used but lacks full standardization, as it includes subjective clinician's judgement. We have compared the performance of the revised Geneva score with the Wells rule, and their usefulness for ruling out PE in combination with D-dimer measurement. METHODS: In 300 consecutive patients, the clinical probability of PE was assessed prospectively by the Wells rule and retrospectively using the revised Geneva score. Patients comprised a random sample from a single center, participating in a large prospective multicenter diagnostic study. The predictive accuracy of both scores was compared by area under the curve (AUC) of receiver operating characteristic (ROC) curves. RESULTS: The overall prevalence of PE was 16%. The prevalence of PE in the low-probability, intermediate-probability and high-probability categories as classified by the revised Geneva score was similar to that of the original derivation set. The performance of the revised Geneva score as measured by the AUC in a ROC analysis did not differ statistically from the Wells rule. After 3 months of follow-up, no patient classified into the low or intermediate clinical probability category by the revised Geneva score and a normal D-dimer result was subsequently diagnosed with acute venous thromboembolism. CONCLUSIONS: This study suggests that the performance of the revised Geneva score is equivalent to that of the Wells rule. In addition, it seems safe to exclude PE in patients by the combination of a low or intermediate clinical probability by the revised Geneva score and a normal D-dimer level. Prospective clinical outcome studies are needed to confirm this latter finding.     

Reducing the use of diagnostic imaging in patients with suspected pulmonary embolism: validation of a risk assessment strategy

Objectives: The aims of this study were to measure the: (i) effects of implementation of a new risk assessment strategy for patients with suspected pulmonary embolism (PE) on the use of imaging and D‐dimer assay; (ii) negative predictive value for PE of a combination of low risk and negative D‐dimer assay; and (iii) compliance of ED clinicians with the strategy. Methods: A non‐randomized clinical trial was conducted in the ED of a 720‐bed teaching hospital between November 2002 and August 2003. Study subjects with suspected PE were compared with 191 randomly selected historical controls. The risk assessment strategy of Kline et al. was disseminated and implemented. Results: The negative predictive value for PE was 99% (95% confidence interval [CI] = 97–100%) in 114 patients with low risk and negative D‐dimer. There was a 21% absolute reduction in the rate of imaging following the implementation of the risk assessment strategy (56% vs 77%, P < 0.001). Conclusion: Low risk combined with a negative D‐dimer result may allow exclusion of PE without imaging.     

Evolving imaging techniques in diagnostic strategies of pulmonary embolism

Modern non invasive diagnostic strategies for pulmonary embolism (PE) rely on the sequential use of clinical probability assessment, D-dimer measurement and thoracic imaging tests. Planar ventilation/perfusion (V/Q) scintigraphy was the cornerstone for more than two decades and has now been replaced by computed tomography pulmonary angiography (CTPA). Diagnostic strategies using CTPA are very safe to rule out PE and have been well validated in large prospective management outcome studies. With the widespread use of CTPA, concerns regarding radiation and overdiagnosis of PE have paved the way for investigating new diagnostic modalities. V/Q single photon emission tomography has arisen as a highly accurate test and a potential alternative to CTPA. However, prospective management outcome studies are still lacking and are warranted before implementation in everyday clinical practice.     

急性肺栓塞的诊断现状分析及诊断策略研究

目的　分析 10年来我院急性肺栓塞 ( PE)的诊断现状并寻找 PE的有效诊断策略。方法　对10年来确诊 PE的患者资料进行分析统计 ,对近 5个月在急诊科就诊的患者利用临床评价联合肺通气 /灌注扫描和 (或 )螺旋 CT这一新的诊断策略来确诊或排除 PE。所有患者随访 3个月。结果　利用新诊断策略后PE的诊断率、3d确诊率、由肺扫描和 (或 )螺旋 CT确诊的比例均明显提高。应用新诊断策略后 ,需要行肺动脉造影检查的比例和 PE新发生率分别是 2 .8%和 0。结论　临床评价联合肺扫描和 (或 )螺旋 CT是诊断 PE的一项有效诊断策略