Systematic Review and Meta-analysis of Outcomes of Patients With Subsegmental Pulmonary Embolism With and Without Anticoagulation Treatment

Risk of recurrent venous thromboembolism and bleeding in patients with acute isolated subsegmental pulmonary embolism

INTRODUCTION

Approximately 10 % of all diagnosed pulmonary embolism are isolated to the subsegmental vessels. The risk of recurrent venous thromboembolism (VTE) in patients with an acute subsegmental pulmonary embolism (SSPE) managed with or without anticoagulant therapy remains poorly understood.

METHODS

This is an observational cohort study including consecutive adult patients diagnosed with acute isolated SSPE between June 01, 2019, and August 31, 2022. We excluded patients with a concomitant diagnosis of deep vein thrombosis and those who had an indication for long-term anticoagulation. The primary outcome was objectively confirmed recurrent VTE.

RESULTS

Overall, 118 patients with acute SSPE were included in the analysis. The mean (± standard deviation [SD]) age of the participants was 59 ± 17 years and 44 % of them had active cancer. Mean (±SD) duration of follow-up was 438 ± 426 days. Seventy-seven patients (65 %) were initially treated with anticoagulation, whereas 41 patients (35 %) were not. Of the 77 patients receiving anticoagulant therapy, 23 (30 %) received extended-duration anticoagulation (beyond 3 months) for secondary prevention. Overall, recurrent VTE events occurred in 6/118 (5 %, 95 % CI 2.4 to 10.7) patients. Four events (4/77 = 5.2 %, 95 % CI 2.0 to 12.6) occurred in initially treated patients. Two recurrent VTE occurred in patients initially left untreated (2/41 = 4.9 %, 95 % CI 1.4 to 16.1). Half of the recurrent VTE occurred in patients with active cancer.

CONCLUSIONS

Most patients diagnosed with an acute SSPE received anticoagulation. The incidence of recurrent VTE detected over time was relatively high, especially in patients with cancer.

Clinical Surveillance vs Anticoagulation Therapy for Isolated Subsegmental Pulmonary Embolism: A Systematic Review of Clinical Outcomes

BACKGROUND

This systematic review aims to evaluate and compare differences in clinical outcomes for adult patients diagnosed with ISSPE who were managed with anticoagulation vs clinical surveillance.

METHODS

PubMed, Embase, ProQuest, Cochrane, and Google Scholar were searched to identify studies evaluating the use of anticoagulation and/or clinical surveillance in patients diagnosed with ISSPE. The search included studies published up to August 3, 2023. Outcomes of interest included 90-day recurrent venous thromboembolism (VTE), major bleeding, and all-cause mortality rates.

RESULTS

Ten studies were included with a total of 1224 patients. Of these patients, 791 were treated with anticoagulation and 433 underwent surveillance. Studies found no difference in recurrent VTE rates, with the majority of studies reporting no recurrence. Of the studies that reported VTE recurrence, rates were .5% to 1.4% for the anticoagulation groups and 3.1% to 3.2% for the surveillance groups. Major bleeding rates were also similar. In anticoagulated patients, major bleeding rates ranged from 1% to 10%. In clinical surveillance patients, the majority found no rate of major bleeding, with 2 studies reporting rates of .8% to 3.2%. Mortality rates ranged widely with no significant differences reported.

CONCLUSION

Clinical surveillance appears to be a safe and effective alternative to anticoagulation in patients with ISSPE. Ninety-day rates of recurrent VTE, major bleeding, and mortality were comparable between groups. These findings highlight the need for updated practice management guidelines to improve patient outcomes.

Subsegmental Pulmonary Embolism

Subsegmental pulmonary embolism (SSPE) is increasingly diagnosed with the growing use and technological advancements of multidetector computed tomography pulmonary angiography. Its diagnosis is challenging, and some presumed SSPE may actually represent imaging artifacts. Indirect evidence and results from small observational studies suggest that SSPE may be more benign than more proximal pulmonary embolism, and may thus not always require treatment. Therefore, guidelines suggest to consider a management strategy without anticoagulation in selected patients with SSPE at low risk of recurrent venous thromboembolism (VTE), in whom proximal deep vein thrombosis is excluded. Recently, a large prospective study among low-risk patients with SSPE who were left untreated showed a higher VTE recurrence risk than initially deemed acceptable by the investigators, and thus was prematurely interrupted after recruitment of 97% of the target population. However, the risk-benefit ratio of anticoagulation for low-risk patients with SSPE remains unclear, and results from randomized trials are needed to answer the question about their optimal management.

Subsegmental pulmonary embolism and anticoagulant therapy: the impact of clinical context

BACKGROUND

Anticoagulation for subsegmental pulmonary embolism (SSPE) is controversial.

AIM

To assess the impact of clinical context on anticoagulation and outcomes of SSPE.

METHODS

We electronically searched computed tomography pulmonary angiogram reports to identify SSPE. We extracted demographic, risk factor, investigations and outcome data from the electronic medical record. We stratified patients according to anticoagulation and no anticoagulation.

RESULTS

From 1 January 2017 to 31 December 2019, we identified 166 patients with SSPE in 5827 pulmonary angiogram reports. Of these, 123 (74%) received anticoagulation. Compared with non-anticoagulated patients, such patients had a different clinical context: higher rates of previous venous thromboembolism (11% vs 0%; P = 0.019), more recent surgery (26% vs 9%; P = 0.015), more elevated serum D-dimer (22% vs 5%; P = 0.004), more lung parenchymal abnormalities (76% vs 61%; P = 0.037) and were almost twice as likely to require inpatient care (76% vs 42%; P < 0.001). Such patients also had twice the all-cause mortality at 1 year (32% vs 16%).

CONCLUSIONS

SSPE is diagnosed in almost 3% of pulmonary angiograms and is associated with high mortality, regardless of anticoagulation, due to coexistent disease processes rather than SSPE. Anticoagulation appears dominant but markedly affected by the clinical context of risk factors, alternative indications and illness severity. Thus, the controversy is partly artificial because anticoagulation after SSPE is clinically contextual with SSPE as only one of several factors.

The value of distinguishing patients with isolated subsegmental pulmonary embolism presenting to two tertiary hospitals in Australia: an observational study

Isolated-subsegmental-pulmonary-embolism (SSPE) is increasingly diagnosed with the use of computed-tomography-pulmonary-angiogram (CTPA). There remains clinical equipoise for management of SSPE with previous studies not accounting for frailty while determining clinical outcomes. Clinical outcomes among patients with isolated SSPE were compared with those with a more proximal PE after accounting for frailty and other risk-factors. This study included all patients with a positive CTPA for pulmonary embolism (PE) admitted between 2017 and 2021 to two Australian-tertiary-hospitals. Frailty was determined by use of the hospital-frailty-risk-score (HFRS). Competing-risk-analysis and Cox-proportional hazard models determined the cumulative-risk of VTE and mortality within 3 months and 1 year of index PE event after adjustment for frailty and other variables. Of 334 patients with positive CTPA for PE, 111 (33.2%) had isolated-SSPE. The mean (SD) age was 64.3 (17.7) years, 50.9% were males and 9.6% were frail. The risk of recurrent VTE within 3-months (0.9% vs. 1.8%, P = 0.458) and within 1-year of follow-up (2.7% vs. 6.3%, P = 0.126) did not differ significantly between patients with isolated SSPE and those with more proximal PE. After adjusted analyses, the cumulative-incidence of recurrent VTE was not different among patients with isolated SSPE within 1 year of index event [subdistribution-hazard-ratio (HR) 0.84, 95% CI 0.19 to 3.60]. Similarly, mortality within 1 year of index event was also not different between the two groups (aHR 1.72, 95% CI 0.92-3.23). The prevalence of SSPE was 33.2% and even after adjustment for frailty these patients had no different clinical outcomes than those with proximal PE.

Unreported incidental pulmonary embolism in patients with cancer: Radiologic natural history and risk of recurrent venous thromboembolism and death

PURPOSE

To assess the risk of recurrent venous thromboembolism (VTE) and death in patients with unreported cancer-associated incidental pulmonary embolism (iPE).

MATERIALS AND METHODS

Matched cohort study on cancer patients with a CT study including the chest between 2014-01-01 and 2019-06-30. Studies were reviewed for unreported iPE, and cases were matched with controls without iPE. Cases and controls were followed for one year, with recurrent VTE and death as outcome events.

RESULTS

Of the included 2960 patients, 171 patients had unreported and untreated iPE. While controls had a one-year VTE risk of 8.2 events per 100 person-years, cases with a single subsegmental iPE had a recurrent VTE risk of 20.9 events, and between 52.0 and 72.0 events per 100 person-years for multiple subsegmental iPE and more proximal iPE. In multivariable analysis, multiple subsegmental and more proximal iPE were significantly associated with the risk of recurrent VTE, while single subsegmental iPE was not associated with the risk of recurrent VTE (p = 0.13). In the subgroup of patients (n = 47) with cancer not in the highest Khorana VTE risk category, no metastases and up to three involved vessels, recurrent VTE occurred in two patients (4.7 cases per 100 person-years). There were no significant associations between iPE burden and risk of death.

CONCLUSION

In cancer patients with unreported iPE, iPE burden was associated with the risk of recurrent VTE. However, having a single subsegmental iPE was not associated with the risk of recurrent VTE. There were no significant associations between iPE burden and risk of death.

Clinical Significance and Outcome in Patients with Asymptomatic Versus Symptomatic Subsegmental Pulmonary Embolism

The clinical significance and optimal therapy of patients with subsegmental pulmonary embolism (SSPE) remain controversial. We used the data in the RIETE Registry to compare the baseline characteristics, treatment, and outcomes during anticoagulation and after its discontinuation in patients with asymptomatic vs. symptomatic SSPE. From January 2009 to September 2022, there were 2135 patients with a first episode of SSPE, of whom 160 (7.5%) were asymptomatic. Most patients in both subgroups received anticoagulant therapy (97% vs. 99.4%, respectively). During anticoagulation, 14 patients developed symptomatic pulmonary embolism (PE) recurrences, 28 lower-limb deep vein thrombosis (DVT), 54 bled, and 242 died. The patients with asymptomatic SSPE had similar rates of symptomatic PE recurrences (hazard ratio (HR): 2.46; 95% CI: 0.37-9.74), DVT (HR: 0.53; 95% CI: 0.03-2.80), or major bleeding (HR: 0.85; 95% CI: 0.21-2.42) to those with symptomatic SSPE, but had a higher mortality rate (HR: 1.59; 95% CI: 1.25-2.94). The rate of major bleeding outweighed the rate of PE recurrences (54 major bleeds vs. 14 PE recurrences), and the rate of fatal bleeds outweighed the rate of fatal PE recurrences (12 vs. 6 deaths). After discontinuing anticoagulation, the patients with asymptomatic SSPE had a similar rate of PE recurrences (HR: 1.27; 95% CI: 0.20-4.55) and a non-significantly higher mortality rate (HR: 2.06; 95% CI: 0.92-4.10). The patients with asymptomatic SSPE had similar rates of PE recurrences to those with symptomatic SSPE, during and after discontinuing anticoagulation. The unexpectedly higher rate of major bleeding than recurrences highlights the need for randomized trials to find the best management.

Management of single subsegmental pulmonary embolism: a prospective observational study at North Shore and Waitakere Hospitals, Auckland

BACKGROUND

Single subsegmental pulmonary embolism is increasingly diagnosed but the benefit to anticoagulate in the absence of concurrent deep vein thrombosis is not consistently established.

AIMS

To investigate the safety of an observational approach in patients with isolated subsegmental pulmonary embolism and the utility of the second lower limb ultrasound after 7 days.

METHODS

Prospective observational study of patients diagnosed with isolated subsegmental pulmonary embolism between July 2016 and July 2020 at North Shore and Waitakere Hospitals, Auckland. The primary outcome was the venous thromboembolism recurrence rate within 3 months of single subsegmental pulmonary embolism diagnosis. Secondary outcomes included all-cause mortality, bleeding complications and the percentage of deep vein thrombosis diagnosed at serial compressive ultrasounds (CUS) of lower limbs.

RESULTS

Among the 48 patients studied (two excluded due to revised diagnosis), no statistically significant differences were found in the baseline characteristics between the anticoagulated (n = 17) and observed (n = 31) groups. After patients with deep vein thrombosis were excluded, comparisons did not reveal significant differences in the primary outcome (0 vs 1 recurrent venous thromboembolism in the anticoagulated vs. observational groups respectively) and the secondary outcomes. In the observational cohort, 77.4% (n = 24) patients had repeat bilateral lower limb CUS after 7 days, and none had deep vein thrombosis diagnosed on the second CUS.

CONCLUSIONS

Withholding anticoagulation was a feasible management option for this cohort of patients with single subsegmental pulmonary embolisms with an absence of deep vein thrombosis. The utility of a second lower limb ultrasound is questionable and would warrant further assessment in a prospective study.

Computed Tomography Angiography for Detection of Pulmonary Embolism in Western Australia Shows Increasing Use with Decreasing Diagnostic Yield

(1) Background: Pulmonary embolism (PE) can be fatal. Computed tomography pulmonary angiography (CTPA) can accurately diagnose PE, but it should be used only when reasonable pre-test probability exists. Overtesting with CTPA exposes patients to excess ionizing radiation and contrast media, while PE overdiagnosis leads to the treatment of small emboli unlikely to cause harm. This study assessed trends in CTPA use and diagnostic yield. We also assessed trends in PE hospitalizations and mortality to indicate PE severity. (2) Methods: Analysis of Western Australian linked administrative data for 2003-2015 including hospitalizations, emergency department (ED) attendances, and CTPA performed at hospitals. Age-sex standardized trends were calculated for CTPA use, PE hospitalizations, and mortality (as a proxy for severity). Logistic regression assessed diagnostic yield of CTPA following unplanned ED presentations. (3) Results: CTPA use increased from 3.3 per 10,000 person-years in 2003 (95% CI 3.0-3.6) to 17.1 per 10,000 person-years (16.5-17.7) in 2015. Diagnostic yield of CTPA increased from 12.7% in 2003 to 17.4% in 2005, declining to 12.2% in 2015 (p = 0.049). PE hospitalizations increased from 3.8 per 10,000 (3.5-4.1) in 2003 to 5.2 per 10,000 (4.8-5.5) in 2015. Mortality remained constant at 0.50 per 10,000 (0.39-0.62) in 2003 and 0.42 per 10,000 (0.32-0.51) in 2015. (4) Conclusions: CTPA increased from 2003 to 2015, while diagnostic yield decreased, potentially indicating overtesting. PE mortality remained constant despite increasing hospitalizations, likely indicating a higher proportion of less severe cases. As treatment can be harmful, this could represent overdiagnosis.

A multicentre observational study of the prevalence, management, and outcomes of subsegmental pulmonary embolism

BACKGROUND

The incidence of subsegmental pulmonary embolism (SSPE) has increased with improvements in imaging technology. There is clinical equipoise for SSPE treatment, with conflicting evidence of improved mortality or reduced venous thromboembolism recurrence with anticoagulation. SSPE studies have significant heterogeneity and often lack adequately matched disease comparator groups.

OBJECTIVES

To determine the prevalence, management, and outcomes of SSPE and compare them to patients with main, lobar, segmental, and no pulmonary embolism (PE).

PATIENTS/METHODS

All adult patients undergoing CT pulmonary angiography (CTPA) between 2013 and 2019, at 3 UK hospitals were included in the study. CTPA reports were text mined for language relating to PE, and then further manually screened for the presence and anatomical location of PE. Patient groups were propensity matched by age, sex, and year of CTPA prior to analysis. 3-month outcomes of major bleeding, VTE recurrence, and death were recorded.

RESULTS

79 (3.8%) SSPEs were identified from 2,055 diagnoses of PE, and 14,300 CTPA reports. 44 (56%) of SSPEs were single artery emboli, 25 (32%) were multiple unilateral emboli, and 10 (13%) were multiple bilateral emboli. Mortality, VTE recurrence and major bleeding were similar at 3 months across all groups. 87.3% of SSPE imaging reports had an additional radiological diagnosis, with pleural effusion (30%), consolidation (19%), and cardiomegaly (19%) being the most common.

CONCLUSION

The prevalence of SSPE was 3.8% of all PEs and there were a substantial number of additional radiological findings in the SSPE group that may have accounted for their symptoms.

Diagnostic Management of Acute Pulmonary Embolism in COVID-19 and Other Special Patient Populations

Venous thromboembolism (VTE), in particular acute pulmonary embolism (PE), has been shown to be a frequent and potentially fatal complication of coronavirus disease 2019 (COVID-19). In response to the observed thrombotic complications, a large number of studies has been devoted to the understanding and management of COVID-19-associated coagulopathy. Notably, only a limited number of mostly retrospective studies has focused on the optimal diagnostic strategy for suspected PE in COVID-19 patients. As in other special populations, the accuracy of diagnostic algorithms for PE-exclusion has been debated in this specific patient subgroup as the specificity of D-dimer assays and clinical decision rules (CDRs) may be lower than normal. From this viewpoint, we discuss the current state-of-the-art diagnostic algorithms for acute PE with a focus on patients with COVID-19 in the perspective of other special patient populations. Furthermore, we summarize current knowledge regarding the natural history of PE resolution with anticoagulant treatment in patients with COVID-19.

Overdiagnosis in the emergency department: a sharper focus

Overdiagnosis occurs when a person's symptoms or life experiences are given a diagnostic label that ultimately causes them more harm than good. We describe the complex drivers of overdiagnosis spanning five interconnected domains, which can lead to numerous negative impacts on patients. Emergency physicians are often tasked with making timely clinical assessments, decisions, and diagnoses that can unintentionally result in overdiagnosis. Three pertinent areas related to overdiagnosis in Emergency Medicine: anaphylaxis, subsegmental pulmonary embolism, and low-risk chest pain are discussed. For a broader perspective, insight on overdiagnosis from medical students and a patient advisor are presented. The perspectives illustrated are meant to spark reflection on: the ethics of labeling a person with a diagnosis, current clinical practices, the limitations of medical education, and patient care and communication in the context of overdiagnosis in the Emergency Department.

[Translated article] Multidisciplinary consensus for the management of pulmonary thromboembolism

We have updated recommendations on 12 controversial topics that were published in the 2013 National Consensus on the diagnosis, risk stratification and treatment of patients with pulmonary embolism (PE). A comprehensive review of the literature was performed for each topic, and each recommendation was evaluated in two teleconferences. For diagnosis, we recommend against using the Pulmonary Embolism Rule Out Criteria (PERC) rule as the only test to rule out PE, and we recommend using a d-dimer cutoff adjusted to age to rule out PE. We suggest using computed tomography pulmonary angiogram as the imaging test of choice for the majority of patients with suspected PE. We recommend using direct oral anticoagulants (over vitamin K antagonists) for the vast majority of patients with acute PE, and we suggest using anticoagulation for patients with isolated subsegmental PE. We recommend against inserting an inferior cava filter for the majority of patients with PE, and we recommend using full-dose systemic thrombolytic therapy for PE patients requiring reperfusion. The decision to stop anticoagulants at 3 months or to treat indefinitely mainly depends on the presence (or absence) and type of risk factor for venous thromboembolism, and we recommend against thrombophilia testing to decide duration of anticoagulation. Finally, we suggest against extensive screening for occult cancer in patients with PE.

Multi-organ point-of-care ultrasound for detection of pulmonary embolism in critically ill COVID-19 patients - A diagnostic accuracy study

Purpose

Critically ill COVID-19 patients have an increased risk of developing pulmonary embolism (PE). Diagnosis of PE by point-of-care ultrasound (POCUS) might reduce the need for computed tomography pulmonary angiography (CTPA), while decreasing time-to-diagnosis.

Materials & methods

This prospective, observational study included adult ICU patients with COVID-19. Multi-organ (lungs, deep vein, cardiac) POCUS was performed within 24 h of CTPA, looking for subpleural consolidations, deep venous thrombosis (DVT), and right ventricular strain (RVS). We reported the scan time, and calculated diagnostic accuracy measures for these signs separately and in combination.

Results

70 consecutive patients were included. 23 patients (32.8%) had a PE. Median scan time was 14 min (IQR 11–17). Subpleural consolidations' diagnostic accuracy was: 42.9% (95%CI [34.1–52.0]). DVT's and RVS' diagnostic accuracy was: 75.6% (95%CI [67.1–82.9]) and 74.4% (95%CI [65.8–81.8]). Their sensitivity was: 24.0% (95%CI [9.4–45.1]), and 40.0% (95%CI [21.3–61.3]), while their specificity was: 88.8% (95%CI [80.8–94.3]), and: 83.0% (95%CI [74.2–89.8]), respectively. Multi-organ POCUS sensitivity was: 87.5% (95%CI [67.6–97.3]), and specificity was: 25% (95%CI [16.9–34.7]).

Conclusions

Multi-organ rather than single-organ POCUS can be of aid in ruling out PE in critically ill COVID-19 and help select patients for CTPA. In addition, finding RVS can make PE more likely, while a DVT would preclude the need for a CTPA.

Registration: www.trialregister.nl: NL8540.

Single versus multiple and incidental versus symptomatic subsegmental pulmonary embolism: clinical characteristics and outcome

It remains unexplored if the clinical picture and outcome of subsegmental pulmonary embolism (SSPE) differ between single versus multiple, and incidental versus symptomatic embolism. Consecutive patients anticoagulated for SSPE at the Mayo Thrombophilia Clinic (03/01/2013-12/31/2020) were followed forward to assess venous thromboembolism (VTE) recurrence, mortality, major bleeding, and clinically relevant non-major bleeding (CRNMB); expressed as a rate per 100 person-years. Among 3878 VTE patients, 1541 had pulmonary embolism including 224 (14.6%) with SSPE either single (n = 139) or multiple (n = 85; 46 bilateral and 39 unilateral emboli); 134 had incidental and 90 symptomatic SSPE. Patients with single were less often symptomatic and less often had coexisting DVT than multiple SSPE. Patients with incidental had a two-fold higher frequency of cancer compared to symptomatic SSPE. During the study period, 1 patient with single and 2 with multiple SSPE had VTE recurrence (rate of 1.14 vs 3.63, p = 0.280). Single SSPE patients experienced 2 episodes of major bleeding (rate of 2.36) while the multiple SSPE group had no major bleeding. Seven patients in each group had CRNMB events (rate of 8.20 vs 13.58 for single and multiple SSPE, respectively, p = 0.282). Patients with single SSPE had a higher death rate compared to multiple SSPE (43.07 vs 22.22, p = 0.031) but no difference was noted after adjusting for cancer (p = 0.388). Also, incidental had similar clinical outcomes to symptomatic SSPE.Interpretation Anticoagulated SSPE patients with single and multiple as well as incidental and symptomatic have a different clinical profile but similar clinical outcomes.

Risk for Recurrent Venous Thromboembolism in Patients With Subsegmental Pulmonary Embolism Managed Without Anticoagulation : A Multicenter Prospective Cohort Study

BACKGROUND

The incidence of pulmonary embolism has been increasing, but its case-fatality rate is decreasing, suggesting a lesser severity of illness. The clinical importance of patients with pulmonary embolism isolated to the subsegmental vessels is unknown.

OBJECTIVE

To determine the rate of recurrent venous thromboembolism in patients with subsegmental pulmonary embolism managed without anticoagulation.

DESIGN

Multicenter prospective cohort study. (ClinicalTrials.gov: NCT01455818).

SETTING

Eighteen sites between February 2011 and February 2021.

PATIENTS

Patients with isolated subsegmental pulmonary embolism.

INTERVENTION

At diagnosis, patients underwent bilateral lower-extremity venous ultrasonography, which was repeated 1 week later if results were negative. Patients without deep venous thrombosis did not receive anticoagulant therapy.

MEASUREMENTS

The primary outcome was recurrent venous thromboembolism during the 90-day follow-up period.

RESULTS

Recruitment was stopped prematurely because the predefined stopping rule was met after 292 of a projected 300 patients were enrolled. Of the 266 patients included in the primary analysis, the primary outcome occurred in 8 patients, for a cumulative incidence of 3.1% (95% CI, 1.6% to 6.1%) over the 90-day follow-up. The incidence of recurrent venous thromboembolism was 2.1% (CI, 0.8% to 5.5%) and 5.7% (CI, 2.2% to 14.4%) over the 90-day follow-up in patients with single and multiple isolated subsegmental pulmonary embolism, respectively. No patients had a fatal recurrent pulmonary embolism.

LIMITATION

The study was restricted to patients with low-risk subsegmental pulmonary embolism.

CONCLUSION

Overall, patients with subsegmental pulmonary embolism who did not have proximal deep venous thrombosis had a higher-than-expected rate of recurrent venous thromboembolism.

PRIMARY FUNDING SOURCE

Heart and Stroke Foundation of Canada and French Ministry of Health Programme Hospitalier de Recherche Clinique.

Effect of a Diagnostic Strategy Using an Elevated and Age-Adjusted D-Dimer Threshold on Thromboembolic Events in Emergency Department Patients With Suspected Pulmonary Embolism: A Randomized Clinical Trial

IMPORTANCE

Uncontrolled studies suggest that pulmonary embolism (PE) can be safely ruled out using the YEARS rule, a diagnostic strategy that uses varying D-dimer thresholds.

OBJECTIVE

To prospectively validate the safety of a strategy that combines the YEARS rule with the pulmonary embolism rule-out criteria (PERC) rule and an age-adjusted D-dimer threshold.

DESIGN, SETTINGS, AND PARTICIPANTS

A cluster-randomized, crossover, noninferiority trial in 18 emergency departments (EDs) in France and Spain. Patients (N = 1414) who had a low clinical risk of PE not excluded by the PERC rule or a subjective clinical intermediate risk of PE were included from October 2019 to June 2020, and followed up until October 2020.

INTERVENTIONS

Each center was randomized for the sequence of intervention periods. In the intervention period (726 patients), PE was excluded without chest imaging in patients with no YEARS criteria and a D-dimer level less than 1000 ng/mL and in patients with 1 or more YEARS criteria and a D-dimer level less than the age-adjusted threshold (500 ng/mL if age <50 years or age in years × 10 in patients ≥50 years). In the control period (688 patients), PE was excluded without chest imaging if the D-dimer level was less than the age-adjusted threshold.

MAIN OUTCOMES AND MEASURES

The primary end point was venous thromboembolism (VTE) at 3 months. The noninferiority margin was set at 1.35%. There were 8 secondary end points, including chest imaging, ED length of stay, hospital admission, nonindicated anticoagulation treatment, all-cause death, and all-cause readmission at 3 months.

RESULTS

Of the 1414 included patients (mean age, 55 years; 58% female), 1217 (86%) were analyzed in the per-protocol analysis. PE was diagnosed in the ED in 100 patients (7.1%). At 3 months, VTE was diagnosed in 1 patient in the intervention group (0.15% [95% CI, 0.0% to 0.86%]) vs 5 patients in the control group (0.80% [95% CI, 0.26% to 1.86%]) (adjusted difference, -0.64% [1-sided 97.5% CI, -∞ to 0.21%], within the noninferiority margin). Of the 6 analyzed secondary end points, only 2 showed a statistically significant difference in the intervention group compared with the control group: chest imaging (30.4% vs 40.0%; adjusted difference, -8.7% [95% CI, -13.8% to -3.5%]) and ED median length of stay (6 hours [IQR, 4 to 8 hours] vs 6 hours [IQR, 5 to 9 hours]; adjusted difference, -1.6 hours [95% CI, -2.3 to -0.9]).

CONCLUSIONS AND RELEVANCE

Among ED patients with suspected PE, the use of the YEARS rule combined with the age-adjusted D-dimer threshold in PERC-positive patients, compared with a conventional diagnostic strategy, did not result in an inferior rate of thromboembolic events.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04032769.

Challenges in Managing Isolated Subsegmental Pulmonary Embolism

This commentary explores the clinical conundrums arising when caring for patients with acute pulmonary embolism isolated to the subsegmental pulmonary arteries. We discuss ways to confirm the radiologic diagnosis, how to distinguish patients for whom anticoagulation is indicated from those who are eligible for structured surveillance without anticoagulation, what surveillance entails, and why ensuring continuity of care matters. We report a case from our own experience that illustrates these decision-making crossroads and highlights the importance of cross-disciplinary collaboration. Because the evidence in the literature is currently weak and indirect, we draw on expert opinion in US and European guidelines, a recent statement from a multidisciplinary consensus panel, and several ongoing well-designed clinical trials. This discussion will help clinicians better manage the spectrum of patients who present with isolated subsegmental embolism.

Endovascular Treatment of Right Heart Masses Utilizing the AngioVac System: A 6-Year Single-Center Observational Study

Objective

To describe our institution's experience with the AngioVac system.

Background

Intracardiac and intravascular masses previously required surgical excision, but now, there are a number of minimally invasive options. With the advent of vacuum aspiration, more specifically the AngioVac System (AngioDynamics, NY, USA), there exists a system with both low mortality and minor complications. However, the number of retrospective studies remains limited. Outcome data for high-risk patients are also limited.

Methods

Data were collected and analyzed in patients who underwent AngioVac therapy at our tertiary care center from January 2014 to December 2020.

Results

Our results demonstrated a 93.3% intraoperative success rate and a 100% intraoperative survival rate. However, a number of complications, including but not limited to hematomas, anemia, and hypotension, occurred, as described below.

Conclusions

Our experiences demonstrated good outcomes and continue to support the usefulness of the AngioVac System. The data also support the use of AngioVac as a treatment option for the debulking or removal of right heart masses in critically ill patients.

Venous thromboembolism: Recent advancement and future perspective

Clinicians have been more and more often encountering patients with venous thromboembolism (VTE), including pulmonary embolism and deep vein thrombosis, leading to the increased importance of VTE in daily clinical practice. VTE is becoming a common issue in Asian countries including Japan. The management strategies of VTE have changed dramatically in the past decade including the introduction of direct oral anticoagulants (DOACs). In addition, there have been several landmark clinical trials assessing acute treatment strategies including thrombolysis and inferior vena cava (IVC) filter. The current VTE guidelines do not recommend the routine use of thrombolysis or IVC filters based on recent evidence; Nevertheless, the prevalence of thrombolysis and IVC filter use in Japan was strikingly high. The novel profiles of DOACs with rapid onset of action and potential benefit of a lower risk for bleeding compared with vitamin K antagonist could make home treatment feasible and is safer even with extended anticoagulation therapy. One of the most clinically relevant issues for VTE treatment is optimal duration of anticoagulation for the secondary prevention of VTE. Considering recent evidence, optimal duration of anticoagulation should be determined based on the risk for recurrence as well as the risk for bleeding in an individual patient. Despite the recent advances for VTE management, there are still a number of uncertain issues that challenge clinicians in daily clinical practice, such as cancer-associated VTE and minor VTE including subsegmental pulmonary embolism and distal deep vein thrombosis, warranting future research. Several clinical trials are now ongoing for these issues, globally as well as in Japan. The current review is aimed to overview the recent advances in VTE management, describe the current status including some domestic issues in Japan, and discuss the future perspective of VTE.

Thrombin Generation and Platelet Function in ICU Patients Undergoing CVVHD Using Regional Citrate Anticoagulation

Background: To investigate pro- and anticoagulant alterations in uremic critically ill patients prior to and during continuous renal replacement therapy. In addition to the conventional thrombin generation assay (TGA), we performed a thrombomodulin-modified variant to better elucidate procoagulant imbalances. Platelet function was determined via multiple electrode aggregometry (MEA) to round off hemostatic analysis.

Methods: We prospectively enrolled patients at surgical intensive care units (ICU) with acute kidney injury undergoing continuous veno-venous hemodialysis using regional citrate anticoagulation. TGA and platelet function testing were performed at baseline (≤ 12 h prior to continuous renal replacement therapy) and on 3 consecutive days (day A–C) of extracorporeal therapy.

Results: We did not observe significant changes in thrombin generation after start or during renal replacement therapy. Ratios of endogenous thrombin potential in patients were significantly increased (p < 0.001) compared to standardized plasma of healthy donors confirming the assumed procoagulant alterations in ICU patients. Test results of the conventional TGA differed significantly (p < 0.05) from those of the thrombomodulin-modified assay. The area under the curve remained below MEA reference values during the entire observation period, indicating a persistent reduction in platelet function.

Conclusion: In summary, in-depth analysis using standard and modified TGA, as well as calculation of endogenous thrombin potential (ETP) ratios, revealed no further aggravation of the procoagulatory shift in the critically ill patient during CVVHD using regional citrate anticoagulation. MEA ruled out the potential impact of platelets.

Clinical Trial Registration: German Clinical Trials Register (DRKS00004336), 29 August 2012; www.drks.de.

Clinical factors and outcomes of subsegmental pulmonary embolism in cancer patients

In the cancer population, patients diagnosed with venous thromboembolism (VTE) are considered to have a threefold increased risk of mortality compared with those without VTE. With the advent of modern computed tomography (CT), the rate of diagnosis of subsegmental pulmonary embolism (SSPE) has increased, likely as a result of improved visualization of the peripheral pulmonary arteries. The clinical significance of SSPE remains unclear because of the lack of randomized controlled clinical trials. The aim of this study was to identify the incidence and risk factors of recurrent proximal PE within 12 months of diagnosis of SSPE in cancer. We performed a retrospective analysis of 206 adult cancer patients who were diagnosed with SSPE from 2014 to 2016 at the University of Texas MD Anderson Cancer Center. At the time of SSPE diagnosis, the majority had metastatic cancer, 108 patients (53.2%) were undergoing chemotherapy, and 23 patients (11.2%) had a history of VTE. Most patients had an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2. Sixty-seven percent of SSPE was discovered incidentally on restaging CT scans, with the majority being a single and isolated event (70.9%). Within 12 months of SSPE diagnosis, 18 patients (8.7%) were found to have a recurrent PE. The patients treated with anticoagulation had a lower rate of PE recurrence (8% vs 13% in those not treated with anticoagulation). Treatment with anticoagulation did not appear to have a significant impact on overall survival (P = .48) when adjusted for ECOG performance status and cancer stage.

Multidisciplinary Consensus for the Management of Pulmonary Thromboembolism

We have updated recommendations on 12 controversial topics that were published in the 2013 National Consensus on the diagnosis, risk stratification and treatment of patients with pulmonary embolism (PE). A comprehensive review of the literature was performed for each topic, and each recommendation was evaluated in two teleconferences. For diagnosis, we recommend against using the Pulmonary Embolism Rule Out Criteria (PERC) rule as the only test to rule out PE, and we recommend using a D-dimer cutoff adjusted to age to rule out PE. We suggest using computed tomography pulmonary angiogram as the imaging test of choice for the majority of patients with suspected PE. We recommend using direct oral anticoagulants (over vitamin K antagonists) for the vast majority of patients with acute PE, and we suggest using anticoagulation for patients with isolated subsegmental PE. We recommend against inserting an inferior cava filter for the majority of patients with PE, and we recommend using full-dose systemic thrombolytic therapy for PE patients requiring reperfusion. The decision to stop anticoagulants at 3 months or to treat indefinitely mainly depends on the presence (or absence) and type of risk factor for venous thromboembolism, and we recommend against thrombophilia testing to decide duration of anticoagulation. Finally, we suggest against extensive screening for occult cancer in patients with PE.

The Positive Rate of Pulmonary Embolism by CT Pulmonary Angiography Is High in an Emergency Department, Even in Low-Risk or Young Patients

OBJECTIVE

The clinical presentation of pulmonary embolism (PE) can be various and misleading. We analyzed patients with suspicion of PE and subsequently performed computed tomography pulmonary angiography (CTPA) in an emergency department of Internal Medicine, focusing on patient groups in which PE might be underestimated in the emergency setting, such as young patients and patients with low clinical probability.

MATERIAL AND METHODS

In 2016 and 2017, all patients receiving a CTPA for investigation of PE were retrospectively evaluated for clinical parameters (age, symptoms, and vital parameters) and D-dimers. The Wells score was calculated.

RESULTS

CTPA was performed in 323 patients (158 female and 165 male; mean age 62 years). The leading symptoms for admission were dyspnea or chest pain; 62% showed intermediate or high risk for PE, calculated by applying the Wells score. In 123 (38%) of all patients, a PE was proved and pathologic age-adjusted D-dimers were found in 97.6%. Thirty of 121 (25%) patients with low risk according to Wells score had a PE. Deep vein thrombosis was verified in 67/123 (55%) patients; 43% (15/35) of all suspicions for PE in patients <40 years were positive with 4/15 (26%), showing a central PE. Younger patients (<40 years) with PE presented more often with tachycardia or tachypnea and chest pain or dyspnea than elderly patients with PE.

CONCLUSION

CTPA frequently proves a PE in patients with suspicion of PE in an emergency department of Internal Medicine. If PE is suspected and CTPA performed accordingly, the presence of PE is quite common even in low-risk patient groups (Wells score) or in young patients <40 years with chest pain or dyspnea.

Clinical Surveillance vs. Anticoagulation For low-risk patiEnts with isolated SubSegmental Pulmonary Embolism: protocol for a multicentre randomised placebo-controlled non-inferiority trial (SAFE-SSPE)

INTRODUCTION

The clinical significance of subsegmental pulmonary embolism (SSPE) is currently unclear. Although growing evidence from observational studies suggests that withholding anticoagulant treatment may be a safe option in selected patients with isolated SSPE, most patients with this condition receive anticoagulant treatment, which is associated with a 90-day risk of recurrent venous thromboembolism (VTE) of 0.8% and major bleeding of up to 5%. Given the ongoing controversy concerning the risk-benefit ratio of anticoagulation for isolated SSPE and the lack of evidence from randomised-controlled studies, the aim of this clinical trial is to evaluate the efficacy and safety of clinical surveillance without anticoagulation in low-risk patients with isolated SSPE.

METHODS AND ANALYSIS

SAFE-SSPE (Surveillance vs. Anticoagulation For low-risk patiEnts with isolated SubSegmental Pulmonary Embolism, a multicentre randomised placebo-controlled non-inferiority trial) is an international, multicentre, placebo-controlled, double-blind, parallel-group non-inferiority trial conducted in Switzerland, the Netherlands and Canada. Low-risk patients with isolated SSPE are randomised to receive clinical surveillance with either placebo (no anticoagulation) or anticoagulant treatment with rivaroxaban. All patients undergo bilateral whole-leg compression ultrasonography to exclude concomitant deep vein thrombosis before enrolment. Patients are followed for 90 days. The primary outcome is symptomatic recurrent VTE (efficacy). The secondary outcomes include clinically significant bleeding and all-cause mortality (safety). The ancillary outcomes are health-related quality of life, functional status and medical resource utilisation.

ETHICS AND DISSEMINATION

The local ethics committees in Switzerland have approved this protocol. Submission to the Ethical Committees in the Netherlands and Canada is underway. The results of this trial will be published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT04263038.

Establishing diagnostic criteria and treatment of subsegmental pulmonary embolism: A Delphi analysis of experts

Background

Improved imaging techniques have increased the incidence of subsegmental pulmonary embolism (ssPE). Indirect evidence is suggesting that ssPE may represent a more benign presentation of venous thromboembolism not necessarily requiring anticoagulant treatment. However, correctly diagnosing ssPE is challenging with reported low interobserver agreement, partly due to the lack of widely accepted diagnostic criteria.

Objectives

We sought to derive uniform diagnostic criteria for ssPE, guided by expert consensus.

Methods

Based on an extensive literature review and expert opinion of a Delphi steering committee, two surveys including statements regarding diagnostic criteria and management options for ssPE were established. These surveys were conducted electronically among two panels, respectively: expert thoracic radiologists and clinical venous thromboembolism specialists. The Delphi method was used to achieve consensus after multiple survey rounds. Consensus was defined as a level of agreement >70%.

Results

Twenty‐nine of 40 invited radiologists (73%) and 40 of 51 clinicians (78%) participated. Following two survey rounds by the expert radiologists, consensus was achieved on 15 of 16 statements, including on the established diagnostic criteria for ssPE (96% agreement): a contrast defect in a subsegmental artery, that is, the first arterial branch division of any segmental artery independent of artery diameter, visible in at least two subsequent axial slices, using a computed tomography scanner with a desired maximum collimator width of ≤1 mm. These criteria were approved by 83% of the clinical venous thromboembolism (VTE) specialists. The clinical expert panel favored anticoagulant treatment in case of prior VTE, antiphospholipid syndrome, pregnancy, cancer, and proximal deep vein thrombosis.

Conclusion

The results of this analysis provide standard radiological criteria for ssPE that may be applicable in both clinical trials and practice.

D-dimer can help differentiate suspected pulmonary embolism patients that require anti-coagulation

Objectives

Determine whether D-dimer concentration in the absence of imaging can differentiate patients that require anti-coagulation from patients who do not require anti-coagulation.

Methods

Data was obtained retrospectively from 366 hemodynamically stable adult ED patients with suspected pulmonary embolism (PE).

Patients were categorized by largest occluded artery and aggregated into: ‘Require anti-coagulation’ (main, lobar, and segmental PE), ‘Does not require anti-coagulation’ (sub-segmental and No PE), ‘High risk of deterioration’ (main and lobar PE), and ‘Not high risk of deterioration’ (segmental, sub-segmental, and No PE) groups.

Wilcoxon rank-sum test was used for 2 sample comparisons of median D-dimer concentrations. Receiver operating characteristic (ROC) curve analysis was utilized to determine a D-dimer cut-off that could differentiate ‘Require anti-coagulation’ from ‘Does not require anti-coagulation’ and ‘High risk of deterioration’ from ‘Low risk of deterioration’ groups.

Results

The ‘Require anti-coagulation’ group had a maximum area under the curve (AUC) of 0.92 at an age-adjusted D-dimer cut-off of 1540 with a specificity of 86% (95% CI, 81–91%), and sensitivity of 84% (79–90%). The ‘High risk of deterioration’ group had a maximum AUC of 0.93 at an age-adjusted D-dimer cut-off of 2500 with a specificity of 90% (85–93%) and sensitivity of 83% (77–90%).

Conclusions

An age-adjusted D-dimer cut-off of 1540 ng/mL differentiates suspected PE patients requiring anti-coagulation from those not requiring anti-coagulation. A cut-off of 2500 differentiates those with high risk of clinical deterioration from those not at high risk of deterioration. When correlated with clinical outcomes, these cut-offs can provide an objective method for clinical decision making when imaging is unavailable.

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ED providers are faced with risks and benefits when empirically administering anti-coagulation for suspected PE patients.

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We show that D-dimer concentration can be used as a clinical decision making tool to minimize these risks.

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A D-dimer cut-off of 1540 ng/mL can be used to minimize unnecessary anti-coagulation exposure in patients who do not need it.

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Using a 2500 ng/mL D-dimer cut-off minimizes the risk of withholding treatment for those at risk of clinical deterioration.

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Both cut-offs along with clinical gestalt are an objective measure weighing the risks & benefits of empiric anti-coagulation.

Mortality risk associated with venous thromboembolism: a systematic review and Bayesian meta-analysis

BACKGROUND

Venous thromboembolism is associated with increased mortality risk in some populations, but how frequently it is a direct cause of death is unclear. We used data from venous thromboembolism prevention trials to evaluate the causal effect of venous thromboembolism reduction on mortality.

METHODS

We did a systematic review and meta-analysis of randomised controlled trials (RCTs) evaluating venous thromboembolism prevention. We searched MEDLINE, Embase, PubMed, and Web of Science starting from Jan 1, 1993, to March 19, 2018. We included studies of patients who were at elevated risk of venous thromboembolism and were randomly assigned to either anticoagulant or antiplatelet therapy versus placebo or no treatment. We excluded studies with an active control agent (which might mitigate the lethality of venous thromboembolism) and those for which mortality data were unavailable. We modelled heterogeneity in a Bayesian framework, taking overall mortality as a primary endpoint, and pulmonary embolism, fatal pulmonary embolism, and major bleeding as secondary endpoints. We focused our analyses on studies reporting statistically significant effects of prevention on venous thromboembolism endpoints. We report treatment effects as median risk ratios (RRs), wherein a null effect equals 1, with 95% credible intervals (CrIs). This meta-analysis was registered with PROSPERO, CRD42018089697.

FINDINGS

From 4229 studies screened, we identified 86 eligible RCTs; 52, with data from over 70 000 patients, were positive, with significantly increased venous thromboembolism risk in patients in control groups versus treatment groups (RR 2·74, 95% CrI 2·32-3·31, p<0·0001). The meta-analysis established that the causal effect of venous thromboembolism prevention on mortality was null (control group mortality was 3391 [9·8%] of 34 537 patients; treatment group mortality was 3498 [9·8%] of 35 795 patients [RR 1·01, 95% CrI 0·97-1·06; p=0·58]) with low heterogeneity (τ 0·02, 95% CrI 0·00-0·07, p=0·89). Patients in control groups had more pulmonary embolism (RR 2·22, 95% CrI 1·78-2·89, p<0·0001) and fatal pulmonary embolism (1·58, 1·14-2·19, p=0·01), but less major bleeding (0·60, 0·47-0·75, p<0·0001) than those in treatment groups. A meta-analysis with the additional 34 negative studies yielded similar results for all endpoints except fatal pulmonary embolism, where evidence of an effect was weaker (1·42, 1·05-1·91, p=0·02).

INTERPRETATION

The perception that venous thromboembolism is a common cause of mortality should be revised considering the null effect of venous thromboembolism prevention on mortality. Our findings call into question the use of composite endpoints in venous thromboembolism-prevention trials and provide rationale for de-escalation trials.

FUNDING

None.

Pulmonary embolism: update on management and controversies

Pulmonary embolism is a common and potentially fatal cardiovascular disorder that must be promptly diagnosed and treated. The diagnosis, risk assessment, and management of pulmonary embolism have evolved with a better understanding of efficient use of diagnostic and therapeutic options. The use of either clinical probability adjusted or age adjusted D-dimer interpretation has led to a reduction in diagnostic imaging to exclude pulmonary embolism. Direct oral anticoagulation therapies are safe, effective, and convenient treatments for most patients with acute venous thromboembolism, with a lower risk of bleeding than vitamin K antagonists. These oral therapeutic options have opened up opportunities for safe outpatient management of pulmonary embolism in selected patients. Recent clinical trials exploring the use of systemic thrombolysis in intermediate to high risk pulmonary embolism suggest that this therapy should be reserved for patients with evidence of hemodynamic compromise. The role of low dose systemic or catheter directed thrombolysis in other patient subgroups is uncertain. After a diagnosis of pulmonary embolism, all patients should be assessed for risk of recurrent venous thromboembolism to guide duration of anticoagulation. Patients with a venous thromboembolism associated with a strong, transient, provoking risk factor can safely discontinue anticoagulation after three months of treatment. Patients with an ongoing strong risk factor, such as cancer, or unprovoked events are at increased risk of recurrent events and should be considered for extended treatment. The use of a risk prediction score can help to identify patients with unprovoked venous thromboembolism who can benefit from extended duration therapy. Despite major advances in the management of pulmonary embolism, up to half of patients report chronic functional limitations. Such patients should be screened for chronic thromboembolic pulmonary hypertension, but only a small proportion will have this as the explanation of their symptoms. In the remaining patients, future studies are needed to understand the pathophysiology and explore interventions to improve quality of life.

Treatment of Acute Venous Thromboembolism

"Acute venous thromboembolism is a common disease seen by nearly all hospitalists. The advent of low molecular weight heparin (LMWH) several decades ago ushered in the era of early hospital discharge and home treatment. More recently, the direct oral anticoagulants (DOACs) have further simplified outpatient treatment and some offer treatment without parenteral therapy. Use of DOACs for cancer-associated venous thromboembolism is emerging and is a welcome evolution of care to spare oncologic patients the burden of daily LMWH injections."

Concise Review of the Clinical Approach to the Exclusion and Diagnosis of Pulmonary Embolism in 2020

Pulmonary embolism has extremely varied clinical presentations and can be difficult to diagnose. Clinical decision rules can help determine the probability of pulmonary embolism by assessment of the clinical presentation. After the diagnosis, several prognostic rules can be used to risk-stratify and facilitate outpatient treatment of pulmonary embolism. This review addresses the utility of clinical decision rules, biomarkers in the diagnosis of pulmonary emoblism, high-risk patient phenotypes, the use of this data to make disposition decisions for patients with a diagnosis of PE, and recent shifts in the management of pulmonary embolism in the clinical setting.

Isolated Pulmonary Embolism Is Associated With a High Risk of Arterial Thrombotic Disease: Results From the VTEval Study

BACKGROUND

Isolated PE is associated with a higher burden of atherosclerotic disease than other manifestations of VTE.

RESEARCH QUESTION

We hypothesized that the presence of isolated PE may signal a chronically elevated risk of arterial thrombotic disease.

STUDY DESIGN AND METHODS

Data from the VTEval Study, a prospective cohort study enrolling individuals with clinical suspicion and imaging-based diagnosis or exclusion of VTE, were analyzed. Patients with PE received whole-leg ultrasonography to assess presence of DVT. Regularized logistic regression identified features that discriminate between isolated PE and other VTE phenotypes at clinical presentation. Survival analyses were performed to evaluate the crude and adjusted 3-year risks of arterial thrombotic disease, recurrent VTE, and death.

RESULTS

The sample comprised 510 patients. Isolated PE patients (n = 63) had a distinct clinical profile from patients with other VTE phenotypes (n = 447). COPD, peripheral artery disease, atrial fibrillation, and coronary artery disease were significantly more prevalent among patients with isolated PE. Isolated PE patients had significantly higher risk (incidence rate ratio vs DVT-associated PE, 3.7 (95% CI, 1.3-10.8, P = .009); vs isolated DVT, 4.8 (1.7-14.3, P = .001) of arterial thrombotic events (ie, myocardial infarction, stroke/transient ischemic attack). After adjustment for clinical profile and medication intake, the risk of arterial thrombotic events for patients with isolated PE remained quadruple that of other VTE phenotypes (hazard ratio [HR], 3.8 [1.3-10.9], P = .01).

INTERPRETATION

Patients with isolated PE are at higher risk for arterial thrombosis and may require screening for arterial disease and development of novel therapeutic strategies.

CLINICAL TRIAL REGISTRATION

NCT02156401.

Anticoagulant treatment for subsegmental pulmonary embolism

BACKGROUND

Acute pulmonary embolism (PE) is a common cause of death, accounting for 50,000 to 200,000 deaths annually. It is the third most common cause of mortality among the cardiovascular diseases, after coronary artery disease and stroke. The advent of multi-detector computed tomographic pulmonary angiography (CTPA) has allowed better assessment of PE regarding visualisation of the peripheral pulmonary arteries, increasing its rate of diagnosis. More cases of peripheral PEs, such as isolated subsegmental PE (SSPE) and incidental PE, have thereby been identified. These two conditions are usually found in patients with few or none of the classic PE symptoms such as haemoptysis or pleuritic pain, acute dyspnoea or circulatory collapse. However, in patients with reduced cardiopulmonary reserve, classic PE symptoms can be found with isolated SSPEs. Incidental SSPE is found casually in asymptomatic patients, usually by diagnostic imaging performed for other reasons (for example routine CT for cancer staging in oncology patients). Traditionally, all PEs are anticoagulated in a similar manner independent of their location, or number and size of the thrombi. It has been suggested that many patients with SSPE may be treated without benefit, increasing adverse events by a possible unnecessary use of anticoagulants. Patients with isolated SSPE, or incidental PE, may have a more benign clinical presentation compared to those with proximal PEs. However, the clinical significance in patients, and their prognosis, needs to be studied to evaluate whether anticoagulation therapy is required. This is the second update of the Cochrane systematic review published in 2014.

OBJECTIVES

To assess the effectiveness and safety of anticoagulation therapy versus control in patients with isolated subsegmental pulmonary embolism (SSPE) or incidental SSPE.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL and AMED databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 26 November 2019. We also undertook reference checking to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials of anticoagulation therapy versus control in patients with SSPE or incidental SSPE.

DATA COLLECTION AND ANALYSIS

Two review authors inspected all citations identified to ensure reliable assessment. If relevant studies were identified, we planned for two review authors to independently extract data and to assess the methodological quality of identified trials using the criteria recommended in the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

We did not identify any studies that met the inclusion criteria.

AUTHORS' CONCLUSIONS

There is no evidence from randomised controlled trials to assess the effectiveness and safety of anticoagulation therapy versus control in patients with isolated subsegmental pulmonary embolism (SSPE) or incidental SSPE. Well-conducted research is required before informed practice decisions can be made.

Clinical presentation and outcomes in elderly patients with symptomatic isolated subsegmental pulmonary embolism

OBJECTIVES

Data are limited on clinical presentation and outcomes in elderly patients with acute symptomatic isolated subsegmental pulmonary embolism (SSPE). We compared clinical presentation, risk factors, processes of care, and outcomes between elderly patients with SSPE and patients with more proximal pulmonary embolism (PE).

METHODS

We prospectively followed 578 patients aged ≥65 years with acute symptomatic isolated SSPE or proximal PE in a multicentre Swiss cohort study. We compared quality of life at three months using the PEmb-QoL, and examined the independent association between localization of PE and clinical outcomes (recurrent venous thromboembolism [VTE], overall mortality) using regression models with adjustment for potential confounders.

RESULTS

Overall, 11% of patients had isolated SSPE. Patients with SSPE were less likely to have a pulse ≥110/min (3% vs. 13%), but more likely to have active cancer (28% vs. 15%) and to receive outpatient care (11% vs. 4%) than patients with proximal PE. Virtually all patients (98%) with SSPE received anticoagulants. Quality of life did not differ between the groups at 3 months. No patient with SSPE vs. seven patients with proximal PE died from the index PE event. No significant difference was observed for the 3-year cumulative incidence of recurrent VTE (7% vs. 12%) and death (29% vs. 20%). After adjustment, SSPE was not associated with a lower risk of clinical outcomes than proximal PE.

CONCLUSIONS

Clinical presentation and incidences of adverse outcomes did not differ significantly between elderly patients with SSPE or proximal PE, although the power to detect differences might have been limited given the small number of events. Thus, our study does not provide evidence that unselected, elderly patients with SSPE have a more benign clinical course.

Pearls and Myths in the Evaluation of Patients with Suspected Acute Pulmonary Embolism

Significant improvement has been achieved in diagnostic accuracy, validation of probability scores, and standardized treatment algorithms for patients with suspected acute pulmonary embolism. These developments have provided the tools for a safe and cost-effective management for most of these patients. In our experience, however, the presence of medical myths and ongoing controversies seem to hinder the implementation of these tools in everyday clinical practice. This review provides a selection of such dilemmas and controversies and discusses the published evidence beyond them. By doing so, we try to overcome these dilemmas and suggest pragmatic approaches guided by the available evidence and current guidelines.

The problem of under-diagnosis and over-diagnosis of pulmonary embolism

Pulmonary embolism (PE) is an increasingly recognised condition which is associated with significant morbidity and mortality. Despite the better awareness of this serious condition, the diagnosis is still overlooked in many cases with sometimes fatal consequences. Under-diagnosis may be due to several reasons including reliance on non-specific 'classic' symptoms, belief that bedside measurements will likely be abnormal in the setting of acute PE, and confounding factors like co-existent cardiorespiratory diseases or being in an intensive care unit, where the diagnosis may not be considered. At the same time, incidental diagnosis of PE is occurring more often due to frequent use of imaging investigations alongside advancements in CT technology, and dilemma exists as to whether the chance finding of PE requires anticoagulation, especially when identified only at the subsegmental level. This article reviews these two issues of under-diagnosis and over-diagnosis of PE in the current era.

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.