Subsegmental Pulmonary Embolism Research Articles

Controversies in the Management of Acute Pulmonary Embolism in the Emergency Department

Backgroundacute pulmonary embolism is frequently diagnosed in the Emergency Department, and the management approach can be nuanced. Objective: in this narrative review, we synthesize the literature in selected areas of ongoing controversy regarding the diagnostic and management approaches for acute pulmonary embolism (PE) in the Emergency Department, and provide evidence-based recommendations to empower emergency physicians to provide optimal care in these situations. DiscussionD-dimer is used to clinically exclude the diagnosis of PE patients who are stratified as low risk. However by utilizing likelihood ratio and with certain scoring tools, patient historically considered moderate or high risk for PE may safely be able to have the diagnosis excluded with a negative D-dimer. Traditional risk stratification and management strategies can be cautiously applied to patients with concomitant Coronavirus-19 infection while awaiting more definitive studies. There is an increasing trend in the diagnosis of isolated subsegmental PE, and many patients receiving this diagnosis may be treated without anticoagulation provided that they have no evidence of associated DVT and can be closely followed as an outpatient. There is a persistent hesitancy to discharge patients with newly-diagnosed acute PE, and existing well-supported risk stratification tools and clinical decision frameworks can support the emergency physician's decision to safely discharge low-risk patients. Conclusion: this review of the literature empowers emergency clinicians to manage challenging PE cases in the ED.

Improved detection of small pulmonary embolism on unenhanced computed tomography using an artificial intelligence-based algorithm - a single centre retrospective study.

To preliminarily verify the feasibility of a deep-learning (DL) artificial intelligence (AI) model to localize pulmonary embolism (PE) on unenhanced chest-CT by comparison with pulmonary artery (PA) CT angiography (CTA). In a monocentric study, we retrospectively reviewed 99 oncological patients (median age in years: 64 (range: 28-92 years); percentage of female: 39.4%) who received unenhanced and contrast-enhanced chest CT examinations in one session between January 2020 and October 2022 and who were diagnosed incidentally with PE. Findings in the unenhanced images were correlated with the contrast-enhanced images, which were considered the gold standard for central, segmental and subsegmental PE. The new algorithm was trained and tested based on the 99 unenhanced chest-CT image data sets. Based on them, candidate boxes, which were output by the model, were post-processed by evaluating whether the predicted box intersects with the patient's lung segmentation at any position. The AI-based algorithm proved to have an overall sensitivity of 54.5% for central, of 81.9% for segmental and 80.0% for subsegmental PE if taking n = 20 candidate boxes into account. Depending on the localization of the pulmonary embolism, the detection rate for only one box was: 18.1% central, 34.7% segmental and 0.0% subsegmental. The median volume of the clots differed significantly between the three subgroups and was 846.5 mm3 (IQR:591.1-964.8) in central, 201.3 mm3 (IQR:98.3-390.9) in segmental and 110.6 mm3 (IQR:94.3-128.0) in subsegmental PA (p < 0.05). The new algorithm proved to have high sensitivity in detecting PE in particular in segmental/subsegmental localization and may guide to decide whether a second contrast enhanced CT is necessary.

In elderly patients with unilateral subsegmental pulmonary emboli, does therapeutic anticoagulation improve mortality?

In elderly patients with unilateral subsegmental pulmonary emboli, does therapeutic anticoagulation improve mortality?

Stopping anticoagulation for isolated or incidental pulmonary embolism: the STOPAPE RCT protocol.

Is withholding anticoagulation for patients with isolated or incidental subsegmental pulmonary embolism clinically and cost-effective compared with full anticoagulation for 3 months? There has been an increase in the diagnosis of subsegmental pulmonary embolism since the advent of computed tomography pulmonary angiogram to investigate patients with suspected pulmonary embolism. Subsegmental pulmonary embolism is not often detectable with older nuclear medicine-based diagnostic imaging for ventilation/perfusion mismatch. The case fatality of pulmonary embolism has reduced as subsegmental pulmonary embolism diagnoses from computed tomography pulmonary angiogram have increased. There is growing equipoise about the optimal treatment for patients with subsegmental pulmonary embolism, given that full anticoagulation has significant risks of bleeding and subsegmental pulmonary embolism was not often diagnosed previously with ventilation/perfusion scanning and therefore most likely left predominantly untreated prior to the introduction of computed tomography pulmonary angiogram scanning. Determine whether withholding anticoagulation for isolated or incidental subsegmental pulmonary embolism (i.e. subsegmental pulmonary embolism with no coexisting deep-vein thrombosis) reduces the harms of recurrent thromboembolism and major bleeding compared with 3 months of full anticoagulation at 3, 6 and 12 months. Determine the rate of complications of anticoagulation therapy (predominantly bleeding) in patients with isolated subsegmental pulmonary embolism. Determine whether not treating isolated subsegmental pulmonary embolism is acceptable to clinicians and patients. Determine the reclassification rate of subsegmental pulmonary embolism diagnoses made by general reporting radiologists when reviewed by specialist respiratory radiologists and develop a set of rules to improve general radiologists' diagnoses of subsegmental pulmonary embolism. Assess cost-effectiveness of not treating patients with isolated subsegmental pulmonary embolism with anticoagulation, taking a health service perspective. Prospective individually randomised open controlled trial with blinded end-point committee assessment for outcomes, powered for non-inferiority for recurrent venous thromboembolism and for superiority for bleeding events. An internal pilot phase is included for feasibility and acceptability of no anticoagulation. We planned to recruit 1466 patients from at least 50 acute hospital sites. Allowing for a dropout rate of 15%, this would have given us 90% power to detect a reduction in major and clinically relevant non-major bleeding from 7.3% in the anticoagulation arm to 3% in the intervention arm. We were powered to determine that a strategy of no anticoagulation was non-inferior to anticoagulation with an upper margin of a 2.3% increase in recurrent venous thromboembolism from an expected rate of 2% in those who receive full anticoagulation. We also planned to undertake a study comparing acute reporting radiologists' diagnoses of subsegmental pulmonary embolism from all computed tomography pulmonary angiograms with specialist respiratory radiologists. This would have allowed us to determine safety in the pilot study (i.e. patients with pulmonary embolism that was in fact larger than subsegmental would have been identified) and develop guidance for subsegmental pulmonary embolism diagnosis for general radiologists. Patients with lived experience of thrombosis contributed to all aspects of the trial design and were part of the Trial Management Group. The STOPAPE trial was stopped prematurely due to a low recruitment rate in the wake of the COVID pandemic and prioritisation of recovery of the National Institute for Health and Care Research research portfolio. There are no outcome data available for this trial. Separate NIHR Library publications will detail the linked qualitative study examining the views of patients and clinicians around withholding anticoagulation for isolated subsegmental pulmonary embolism as well as presenting all collected data of recruited patients. This article presents independent research funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme as award number NIHR128073. A plain language summary of this research article is available on the NIHR Journals Library Website https://doi.org/10.3310/HRCW7937.

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

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

TAKOTSUBO SYNDROME PRECEDING THE INDEX EVENT: A DANGEROUS CLINICAL SETTING

Abstract We describe the case of a 68–year–old patient who presented to the Emergency Department following an unwitnessed syncopal episode with slow recovery of consciousness. On admission, the patient had dyspnoea together with physical signs of pulmonary congestion. Cardiac ultrasound showed severe left ventricular dysfunction with an ejection fraction of 30%, and apical and paraapical akinesis. The admission electrocardiogram showed sinus tachycardia and diffuse repolarization abnormalities, hs TnI was elevated and BNP vl blood gas analysis were unremarkable. During observation in the Emergency Department, the patient experienced epileptic seizure, promptly resolved by intravenous Midazolam. Contrast–enhanced chest CT ruled out aortic dissection disclosing a clinically irrelevant subsegmental pulmonary embolism. A non–contrast CT scan of the brain yielded negative results. In consideration of the atypical clinical presentation and scattered evidence of an acute coronary syndrome, the patient was admitted to our Cardiac Intensive Care Unit (CICU) for additional diagnostic workup delaying coronary angiography in the presence of stable TnI elevation. Three hours after admission the patient continued showing altered consciousness and a subsequent brain CT was performed, demonstrating an intraparenchymal hemorrhagic spreading. Repeat ECGs showed precordial T wave inversion and prolongation of the QT interval. These data, together with LV apical dysfunction, raised the suspicion of Takotsubo syndrome secondary to an acute cerebrovascular event. During the hospital stay, recovery of consciousness, spontaneous absorption of the cerebral hemorrhagic spread and complete recovery of left ventricular function at repeat cardiac ultrasound examinations were observed, confirming the almost unequivocal diagnosis of Takotsubo syndrome. The patient was discharged uneventfully and was scheduled for an outpatient coronary CT scan. This case underscores the crucial importance of a thorough clinical assessment in the management of complex patients in the presence of nonunivocal clinical signs and misleading blood test and imaging data. Moreover, Takotsubo syndrome is a protean clinical entity that can precede the index event as in our patient, i.e. cerebral hemorrhage. Misclassification of these patients as having an acute coronary syndrome could have led to the initiation of antithrombotic therapy, with potential fatal outcomes for the patient.

Subsegmental Pulmonary Embolism Post Cesarean Section: A Case Report

Diagnosing pulmonary embolism during pregnancy and the postpartum period can indeed be challenging due to overlapping symptoms with normal pregnancy changes. It's important for healthcare providers to maintain a high index of suspicion and use appropriate diagnostic tools, such as imaging studies like CT pulmonary angiography or ventilation-perfusion scans, while considering the maternal and fetal risks involved in the diagnostic process. We report a case of postpartum subsegmental pulmonary embolism.

Cancer-Associated Thrombosis: Management of a Patient With an Isolated Calf Deep Vein Thrombosis.

The Oncology Grand Rounds series is designed to place original reports published in the Journal into clinical context. A case presentation is followed by a description of diagnostic and management challenges, a review of the relevant literature, and a summary of the authors' suggested management approaches. The goal of this series is to help readers better understand how to apply the results of key studies, including those published in Journal of Clinical Oncology, to patients seen in their own clinical practice.Venous thromboembolism occurs frequently in patients with cancer and is the second leading cause of death, after the cancer itself. There is a well-established consensus of the need for anticoagulation in patients with a proximal deep vein thrombosis or pulmonary embolism. But with improved imaging technology and widescale use of contrast imaging for cancer staging, many incidental pulmonary emboli are detected in patients with cancer. Furthermore, many isolated distal deep vein thromboses and subsegmental pulmonary emboli are identified. There have been questions if these small or asymptomatic thromboses require anticoagulation management similar to more proximal or symptomatic thromboses. In this Oncology Grand Rounds, we will review the existing evidence for these situations. We will also review management strategies for cancer-associated thrombosis, reflecting the evolving drugs and evidence over the past 20 years.

Subsegmental Pulmonary Emboli: When to Withhold Anticoagulation?

Subsegmental Pulmonary Emboli: When to Withhold Anticoagulation?

Risk of Recurrent Venous Thromboembolism in Patients with Acute Isolated Subsegmental Pulmonary Embolism - a Single Center Chart Review

Introduction: The incidence of pulmonary embolism (PE) has been increasing, but its case-fatality rate is decreasing over time, suggesting overdiagnosis, a lesser severity of the illness and/or improvements in treatment strategies. Approximately 10-14% of all diagnosed PE 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 and analysis: This is an observational, retrospective cohort study of adult patients diagnosed with an acute isolated SSPE (single or multiple) at The Ottawa Hospital, Ontario, Canada, from June 01, 2019, to August 31, 2022. Data on diagnosis and follow-up were collected through a retrospective review of the medical records. Among inclusion criteria, no selection was made on provoking factors or on presence/absence of symptoms at presentation. We excluded those patients with concomitant diagnosis of deep vein thrombosis (DVT) who were started on anticoagulation and those who had an indication for long-term anticoagulation at the time of SSPE diagnosis (e.g. atrial fibrillation). The primary outcome was recurrent VTE events other than SSPE, occurring after the diagnosis among patients managed without anticoagulation, and after treatment initiation among those treated with anticoagulation. Results: Overall, 120 patients with a diagnosis of acute SSPE were included in the analysis. The mean age of the participants was 59 +/- 3 years, 47% were women, the mean body weight was 76 +/- 4 kg, and 35% of them had active cancer. Seventy-nine patients (66%) were treated with anticoagulation, whereas 41 patients (34%) were not. The most frequent treatment was direct oral anticoagulant, being used in 64/79 patients (81%), whereas 15/79 patients (19%) received low molecular weight heparin. Most patients were treated for 3-6 months. Twenty-one (28%) of treated patients continued long-term anticoagulation for secondary prevention. Individuals with active cancer at time of SSPE diagnosis were 32/79 (41%) and 10/41 (24%), respectively among treated and not treated patients. Overall, duration of follow-up was 452 +/- 77 days; 7 patients were lost to follow-up. Recurrent VTE events occurred in 7/113 (6.2%) patients: 5/75 (6.7%, 95% CI 2.2 to 14.9) of them were diagnosed in the treatment group (2 occurred while on anticoagulation and 3 after discontinuation of treatment) and the other 2/38 (5.3%, 95% CI 0.6 to 17.8) were detected among patients managed without anticoagulation. Recurrences were mostly represented by more proximal PEs (5 patients), one patient had an upper extremity DVT and the other one was diagnosed with both DVT and proximal PE. Conclusions: In our retrospective cohort study, most patients diagnosed with an acute SSPE received anticoagulation. The prevalence of recurrent thromboembolic events detected over more than a year follow-up was relatively high, with 6.7% and 5.3%, respectively, among patients treated with anticoagulation and those managed without anticoagulation. Further data are needed to better understand the natural history of this thrombotic complication and to identify the right patients who would benefit from anticoagulation.

Accuracy of the Diagnosis of Subsegmental Pulmonary Embolism Among General Radiologists

Background: Diagnosis and treatment of subsegmental pulmonary embolism (SSPE) are challenging. Contrary to segmental PE, little is known about the accuracy of the diagnosis of SSPE Methods A retrospective matched cohort study was conducted at a university-affiliated community hospital. Computed tomographic angiography (CTAs) were reviewed from August 2018 to December 2021. Patients who were 18-year-old or older with the diagnosis of SSPE were included. Patients with a concurrent segmental PE or deep venous thrombosis (DVT) were excluded. Another radiologist reviewed each CTA. Results Total of 43 patients with SSPE without segmental PE were identified. The mean age of subjects was 67 years. 24 (56%) patients were males, and 41 (95%) were white. 42 (97%) of CTAs were performed for suspected PE. One case was found incidentally. Forty patients (93%) received therapeutic anticoagulation. Three patients (7%) were discharged from the Emergency Department (ED) without therapeutic anticoagulation. The average duration of anticoagulation therapy was four-months. Another radiologist's review of the CTA on admission revealed a discordant diagnosis: 13 out of 43 (30%) cases were reported negative for SSPE. One case was reported for segmental PE Conclusion The accuracy of the diagnosis of SSPE is low as the discordance rate by different radiologists is high.More studies are needed to establish the diagnosis and guide treatment of SSPE.

Subsegmental PE: When to Withhold Anticoagulation?

Subsegmental PE: When to Withhold Anticoagulation?

Abstract 17700: Double Trouble With Identification of Isolated Sub-Segmental Pulmonary Embolism Using ICD-10 Discharge Diagnosis Codes: The PE-EHR+ Study

Introduction: International Classification of Diseases 10 th revision (ICD-10) discharge diagnosis codes are widely used for research studies that use electronic databases. The accuracy of the codes for identifying patients with isolated sub-segmental pulmonary embolism (issPE) is unknown. Methods: We used data from the Mass General Brigham (MGB) health system (01/2016-12/2021) and included 1,734 patients randomly selected from 3 groups: Patients with ICD-10 Principal Discharge Diagnosis codes for PE, patients with secondary Discharge Diagnosis codes for PE, and patients with no ICD-10 codes for PE. Weighted estimates were obtained by considering the total number of hospitalizations in each category at MGB hospitals. Accuracy of the codes was assessed by two independent physicians who reviewed discharge summaries, daily notes, and radiology reports. Results: Of 1,734 records reviewed, 1,712 were included (age: 60.6±17.8 years, 52.3% female). Manual chart review found 865 patients with acute PE, including 104 (12.0%) with issPE. Of these 104 patients, 103 (98.3%) had ICD-10 codes for PE. However, only in 15 (14.6%) cases, PE codes were specified as being limited to subsegmental vessels (issPE). In turn, in another 43 cases, Principal-or-secondary ICD-10 codes for issPE were listed but the patients did not have acute issPE during index hospitalization per review of records. The sensitivity and specificity for issPE codes in Principal or secondary discharge position were 14.4% and 97.3% (Table, panel A). Positive predictive value in the weighted sample was only 26.2% (Table, panel B). Conclusions: ICD-10 codes are insensitive and have a poor positive predictive value for detection of isolated subsegmental PE and should not be used for case identification for research purposes or quality improvement initiatives.

Long-Term Erythrocytapheresis Did Not Prevent Development of Severe Pulmonary Hypertension in Sickle Cell Disease

Background The WHO classifies pulmonary hypertension into five different groups based on pathophysiology, clinical presentation, and therapeutic options. The development of pulmonary hypertension (PH) in sickle cell disease (SCD) is multifactorial and can cause devastating complications. Erythrocytapheresis is utilized in patients with SCD who have multiple comorbidities or are unresponsive to first-line treatments like hydroxyurea. It is hypothesized that treatment with long-term erythrocytapheresis (LTE) could slow the progression to pulmonary hypertension by modifying the pathophysiology of the disease process. However, limited clinical data supports this transfusion modality [1]. Case Description The patient is a 17-year-old female with a history of SCD, obstructive sleep apnea (OSA), nocturnal hypoxemia, and recurrent pain crises maintained on LTE every four weeks for the past seven years. She had previously failed hydroxyurea therapy. She underwent a tonsillectomy and adenoidectomy seven years ago to treat OSA. The patient had an echocardiogram five years ago, which showed normal biventricular function and tricuspid regurgitation jet velocity. Recently she presented to the emergency department with cough, shortness of breath, fever, diarrhea, and nausea lasting for three days. Initial assessment revealed elevated liver enzymes, elevated BNP, hyperbilirubinemia, hemoglobin of 9.5 g/dL, and oxygen saturations in the 80's. Echo revealed right ventricular dysfunction and right atrial and ventricular enlargement with a tricuspid regurgitation jet velocity of 4.29 m/s and estimated right ventricular systolic pressure 90% systemic, as seen in figure 1. The patient was admitted to the PICU under concern of pulmonary hypertension crisis. She underwent a right cardiac catheterization three days into her admission and was diagnosed with severe pulmonary hypertension with a mean pulmonary artery pressure of 49 mmHg. Pulmonary capillary wedge pressure was 11 mmHg, and pulmonary vascular resistance was calculated to be 18 wood units x m 2 with 20 PPM of nitric oxide and 80% FiO2 the PVR decreased to 11 woods units x m 2 (figure 2). CTA showed subsegmental thrombosis and vascular surgery was consulted for evaluation for endarterectomy, but they decided she was not a surgical candidate. She was initiated on anticoagulation therapy with enoxaparin, sildenafil, and bosentan. Conclusions The cause of PH in this patient appears to be multifactorial. Possible etiologies include SCD-related, primary pulmonary hypertension, or subsegmental pulmonary embolism. Although LTE is increasingly used in the management of SCD, providers should not assume that a patient receiving this treatment will not progress to develop complications. Some patients on LTE may also develop progressive CNS vasculopathy and are still at risk for developing hypertension. Patients with SCD should be screened for PH if they are symptomatic or have comorbid conditions. This patient had a history of nocturnal hypoxemia and OSA, which some studies indicate are associated with pulmonary hypertension in adolescents with SCD. Screening for nocturnal hypoxemia and OSA is recommended in SCD to identify patients at high risk of PH development [2].

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.

Right ventricular failure due to acute pulmonary embolism associated with Graves’ disease: A case report

Background Graves' disease is a prevalent endocrine disorder characterized by diverse clinical manifestations affecting multiple organs, exhibiting varying degrees of severity. Cardiovascular system involvement is one of the most common manifestations, which include palpitation, tachycardia, cardiomyopathy, atrial fibrillation, pulmonary hypertension, or heart failure. Additionally, excessive thyroid hormone can lead to a hypercoagulable state, increasing the risk of venous thrombosis. However, thrombotic events, particularly deep vein thrombosis, cerebral venous thrombosis, or pulmonary embolism, are rare complications of Graves’ disease. Case presentation In this report, we present the case of a 53 years old woman who presented with progressively worsening dyspnea, orthopnea, paroxysmal nocturnal dyspnea, bilateral leg edema, and jaundice for 2 weeks. She had also reported a weight loss of 4 kilograms within 3 months. Upon admission to our hospital, she initially received a diagnosis of congestive heart failure with atrial fibrillation and thyrotoxicosis. Following diuretic therapy, the patient developed hypotension and severe hypoxemia. Subsequent investigation revealed acute right ventricular failure due to an acute sub-segmental pulmonary embolism, which was confirmed by computed tomography of the pulmonary artery. The patient's condition improved after resuscitation involving intravenous fluid administration to increase right ventricular preload, intravenous vasopressor infusion to elevate systemic blood pressure, management of severe thyrotoxicosis, and intravenous administration of heparin. Conclusion Graves’ disease, accompanied by hemodynamic disturbances due to acute right ventricular failure, necessitates admission to the intensive care unit for resuscitation and close monitoring. Although acute pulmonary embolism is an uncommon condition associated with Graves’ disease, it should be considered, particularly in patients who develop acute right ventricular failure.

Prevalence of and Eligibility for Surveillance Without Anticoagulation Among Adults With Lower-Risk Acute Subsegmental Pulmonary Embolism

Approximately 8% of acute pulmonary emboli are confined to the subsegmental arteries. The 2016 and 2021 American College of Chest Physicians (CHEST) guidelines and expert panel reports suggest the use of structured surveillance without anticoagulation for select ambulatory patients with subsegmental pulmonary embolism who do not have active cancer, deep vein thrombosis, impaired cardiopulmonary reserve, marked symptoms, or increased risk of recurrent venous thromboembolism; however, guideline uptake in community practice is unknown, as is the proportion of outpatients eligible for surveillance. To describe the prevalence of surveillance among outpatients with acute subsegmental pulmonary embolism and to estimate the proportion of patients eligible for structured surveillance using modified CHEST criteria. This retrospective cohort study was conducted across 21 US community hospitals in the Kaiser Permanente Northern California integrated health system from January 1, 2017, to December 31, 2021. Adult outpatients with acute subsegmental pulmonary embolism were included. Patients with the following higher-risk characteristics were excluded: codiagnoses requiring hospitalization, non-low-risk vital signs (ie, systolic blood pressure <90 mm Hg, pulse ≥110 bpm, or peripheral cutaneous pulse oximetry ≤92%), prediagnosis anticoagulant use, or hospice care. Data analysis was performed from November 2022 to February 2023. The main outcomes were the (1) prevalence of surveillance and (2) eligibility for surveillance using 2 sets of criteria: the CHEST criteria modified by excluding patients with higher-risk characteristics or right ventricular dysfunction and a stricter set of criteria requiring age younger than 65 years and no more than 1 embolus. The prevalence of structured surveillance was calculated and the proportion of patients eligible for surveillance was estimated. Of the 666 outpatients with acute subsegmental pulmonary embolism included in this study, 229 with lower-risk characteristics were examined. Their median age was 58 (IQR, 42-68) years; more than half were men (120 [52.4%]) and self-identified as non-Hispanic White (128 [55.9%]). Six patients (2.6%) were initially not treated with anticoagulants. Among the lower-risk cohort, only 1 patient (0.4% [95% CI, 0.01%-2.4%]) underwent structured surveillance, without 90-day sequelae. Thirty-five patients (15.3% of the lower-risk group and 5.3% of the full cohort) were surveillance eligible using modified CHEST criteria. Fifteen patients (6.6% of the lower-risk group and 2.3% of the full cohort) were surveillance eligible using stricter criteria. In this cohort study of lower-risk outpatients with subsegmental pulmonary embolism, few were eligible for structured surveillance, and only a small proportion of eligible patients underwent surveillance despite the CHEST guideline. If forthcoming trials find surveillance safe and effective, substantial uptake into clinical practice may require more than passive diffusion.

Safety of the Pulmonary Embolism Rule-Out Criteria Rule: Findings from the Registro Informatizado de la Enfermedad TromboEmbolica venosa (RIETE) Registry.

The diagnostic strategy for pulmonary embolism (PE) includes a D-dimer test when PE probability is low or intermediate, but false positive D-dimer results are frequent and can result in an unnecessary computed tomography pulmonary angiogram. The PE rule-out criteria (PERC) rule excludes PE without D-dimer testing when pre-test probability is <15%. The aim of this study was to assess the safety of the PERC rule strategy in patients included in the Registro Informatizado de la Enfermedad TromboEmbolica venosa (RIETE) registry. This retrospective cohort study used data from the RIETE registry, an ongoing, international prospective registry of patients with objectively confirmed venous thromboembolism. The primary outcome was the failure rate of the PERC strategy, represented by the proportion of PERC-negative (PERC-N) patients with a PE included in the registry. Secondary outcomes were a comparison of the clinical characteristics, treatment strategy, and outcome of PERC-N versus PERC-positive (PERC-P) patients at 3 months. From 2001 to 2021, 49,793 patients with acute PE were enrolled in the RIETE registry. We included 48,903 in the final analysis after exclusion of 890 patients with an undetermined PERC status. Only 346 patients were PERC-N with a failure rate of 0.7% (95% confidence interval 0.6-0.8%). PERC-N patients presented more frequently with chest pain, but less often with dyspnea, syncope or hypotension. They had also sub-segmental or segmental PE more frequently, were more often treated with direct oral anticoagulants, and received mechanical or pharmacological thrombolysis less often. In addition, PERC-N patients had a lower incidence of recurrent deep vein thrombosis, major bleeding, and death attributed to PE during the 3-month follow-up. A low failure rate of the PERC rule was observed in the RIETE registry, thus supporting its use to safely identify patients with an unlikely probability of PE.

Assessment of the Utilization of Validated Diagnostic Predictive Tools and D-Dimer in the Evaluation of Pulmonary Embolism: A Single-Center Retrospective Cohort Study from a Public Hospital in New York City.

A significant increase in the use of computed tomography with pulmonary angiography (CTPA) for the diagnosis of pulmonary embolism (PE) has been observed in the past twenty years. We aimed to investigate whether the validated diagnostic predictive tools and D-dimers were adequately utilized in a large public hospital in New York City. We conducted a retrospective review of patients who underwent CTPA for the specific indication of ruling out PE over a period of one year. Two independent reviewers, blinded to each other and to the CTPA and D-dimer results, estimated the clinical probability (CP) of PE using Well's score, the YEARS algorithm, and the revised Geneva score. Patients were classified based on the presence or absence of PE in the CTPA. A total of 917 patients were included in the analysis (median age: 57 years, female: 59%). The clinical probability of PE was considered low by both independent reviewers in 563 (61.4%), 487 (55%), and 184 (20.1%) patients based on Well's score, the YEARS algorithm, and the revised Geneva score, respectively. D-dimer testing was conducted in less than half of the patients who were deemed to have low CP for PE by both independent reviewers. Using a D-dimer cut-off of <500 ng/mL or the age-adjusted cut-off in patients with a low CP of PE would have missed only a small number of mainly subsegmental PE. All three tools, when combined with D-dimer < 500 ng/mL or <age-adjusted cut-off, yielded a NPV of > 95%. All three validated diagnostic predictive tools were found to have significant diagnostic value in ruling out PE when combined with a D-dimer cut-off of <500 ng/mL or the age-adjusted cut-off. Excessive use of CTPA was likely secondary to suboptimal use of diagnostic predictive tools.

Comparison of Dual-Energy Computed Tomography Pulmonary Angiography-Derived Contrast Enhancement with Standard Dual-Energy Pulmonary Angiography in Diagnosing Subsegmental Pulmonary Embolism: A Prospective Study.

Objective In this study, we compare the diagnostic accuracy of dual-energy (DE) computed tomography pulmonary angiography (CTPA) derived contrast enhancement (DECTPA, CTPA images with iodine maps) with standard dual-energy pulmonary angiography (SCTPA) for diagnosis of subsegmental pulmonary embolism in the cases with clinical suspicion of acute pulmonary embolism (APE). Materials and Methods We included 50 cases with clinical suspicion of APE that were referred for CTPA. All the patients underwent CTPA in the dual-energy protocol. Two radiologists evaluated the images. The first radiologist interpreted the SCTPA images (vascular images) and the second radiologist interpreted the DECTPA (CTPA images with iodine maps) for findings of APE. We calculated the sensitivity, specificity, and negative predictive value of DECTPA vis-à-vis SCTPA images. Results The DECTPA with the advantage of iodine map utilization yielded higher detection of thrombi in peripheral subsegmental arteries (72 vs. 99; p = - 0.001) as compared to the SCTPA images by identification of 18 new perfusion defects (interquartile range [IQR]: 0-1) that were consistent with APE. Filling defects were identified in 27 (IQR: 0-4) more subsegmental arteries supplying these 18 areas, which were not detected on SCTPA alone. These 18 perfusion defects were identified in 13 cases. In these 13 cases, 4 new cases were diagnosed that were negative on CTPA ( p = -0.125). In the evaluation of the APE, sensitivity and specificity were calculated and it was found that DECTPA showed 100% sensitivity and 86% specificity with 100% negative predictive value in the detection of thrombi as compared to the routine CTPA. Conclusion DECTPA has higher sensitivity and negative predictive value in the detection of the subsegmental perfusion defect identification as compared to SCTPA.