Diagnosis Of Subsegmental Pulmonary Embolism Research Articles

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.

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.

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.

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.

Evaluation of Clinical and Radiological Factors Associated with Thrombosis Recurrence in Cancer Associated Subsegmental Pulmonary Embolism

Background: Acute pulmonary embolism (PE) is a leading cause of morbidity in the cancer population. The availability of computed tomographic (CT) scans and CT-pulmonary angiography (CT-PA) has allowed for better visualization of the peripheral pulmonary arteries and assessment of PE, resulting in greater detection of subsegmental pulmonary embolism (SSPE). The clinical outcomes and the factors determining PE recurrence are not clear in the cancer related-SSPE population.Our objectives were to evaluate the incidence of recurrent PE within 12 months of SSPE in cancer patients and to identify factors influencing PE recurrence and overall survival (OS).Methods: A retrospective analysis (2014-2015) of adult cancer patients followed at The University of Texas MD Anderson Cancer Center who were diagnosed with SSPE. The primary outcome was the rate of PE recurrence within 12 months of SSPE diagnosis and to identify clinical and/or radiological factors associated with PE recurrence and overall survival. The study was approved by IRB with consent waiver.Results: Among 158 patients, 62% were male, 73.9% with stage IV disease, and 58.9% were on chemotherapy at time of SSPE diagnosis. Most of the patients had an ECOG performance status of 0 to1 (74.1%) and had no prior history of venous thromboembolism (VTE) (89.9%). The majority of SSPE (75.3%) were diagnosed incidentally by staging CT versus 24.7% by CT-PA. Amongst clinical factors, active chemotherapy and prior history of VTE at the time of SSPE diagnosis seemed to influence the probability of PE recurrence on the univariate analysis, however there was no statistical significance on logistic regression analysis. The radiological features of SSPE did not impact the rate of PE recurrence (Table 1). A total of 120 patients (75.9%) were treated with anticoagulation alone, 8 patients (5.1%) had IVC filter placement, 14 patients (8.9%) received both anticoagulation and IVC filter, and 16 patients (10.1%) had no therapy. At 12-month follow-up, 15 of 158 patients (9.5%) had PE recurrence. There was no significant effect of anticoagulation in OS, after adjustment for performance status (PS) and tumor stage (TS) (P=0.3971), or by PE recurrence status (P=0.4).Conclusion: The study showed a clinical significant rate of PE recurrence among cancer patients with SSPE, which is comparable to rates of PE recurrence from data of cancer-specific VTE clinical trials. Specific clinical or radiological predictors for PE recurrence were not identified. The PS and TS were found to be the main predictors of survival in this population, regardless of the secondary prevention strategy used. [Display omitted] DisclosuresRojas Hernandez:Daichii Sankyo: Research Funding.

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.

Challenges in the diagnosis of sub-segmental pulmonary embolism in symptomatic patients: a case report.

Challenges in the diagnosis of sub-segmental pulmonary embolism in symptomatic patients: a case report.

Sub‐segmental pulmonary embolism in three academic teaching hospitals: a review of management and outcomes

The availability of computed tomography pulmonary angiography (CTPA) has led to an increase in the diagnosis of sub-segmental pulmonary embolism (SSPE). Current clinical practice guidelines do not make any treatment distinctions for SSPE, though the benefits of anticoagulation for SSPE have not been established. To review the frequency of pulmonary embolism and sub-segmental pulmonary embolism identified through CTPA as well as their management. Cross-sectional review of the charts of 2213 patients who underwent CTPA in three Hamilton teaching hospitals from 2009 to 2011. In-depth review of the charts of patients with SSPE was undertaken to determine the frequency with which patients received anticoagulation therapy for SSPE, as well as bleeding complications and recurrent thrombosis. A total of 2216 CTPAs were reviewed. The frequency of PE was 24.8% (n=550). The most frequent filling defect was SSPE in 82 patients (3.9% of total scans and 15.0% of identified PEs). In 55 of these 82 SSPEs, an alternative diagnosis to PE was identified on CT to explain the patients' symptoms. Approximately 52.4% (n=43) received anticoagulation for SSPE. Major life-threatening bleeding complications occurred in two of the 43 who received anticoagulation for SSPE. There was no documented recurrent thrombosis in any patients with SSPE, with or without anticoagulation. A substantial proportion of patients received anticoagulation for SSPE (52%) and two developed life-threatening bleeding complications. Randomized controlled trial data are needed to further investigate the risks and benefits of anticoagulation in patients with SSPE.

Diagnosis of Isolated Sub-Segmental Pulmonary Embolism on Computed Tomography Pulmonary Angiography; How Sure Are We of the Diagnosis?

Abstract 714Computed tomography pulmonary angiography (CTPA) has become the standard diagnostic modality for the detection of pulmonary embolism (PE). More recently, the advent of multidetector CT has allowed better visualization of segmental and sub-segmental pulmonary arteries. Hence, the proportion of patients with suspected PE, in whom an isolated sub-segmental pulmonary embolism (SSPE) is reported, has increased. The clinical importance of isolated SSPE diagnosis is unclear. The increased incidence of SSPE diagnosed by CTPA seems to be associated with a lower severity of illness and lower mortality in the CTPA era. Nonetheless, a large majority of patients with SSPE are treated with oral anticoagulant therapy. Current guidelines recommend to anticoagulate patients with unprovoked thrombosis for a minimum of three months and to consider long-term treatment in the absence of contra-indications. Therefore, accurate diagnosis of SSPE is important before exposing patients to potentially indefinite anticoagulant therapy and its associated complications. We sought to determine the rate of agreement between radiologists for the diagnosis of isolated SSPE in patients presenting with suspected PE, and report the three-month outcome of patients who had been diagnosed with an isolated SSPE.A retrospective cohort study of consecutive patients with suspected acute PE who underwent CTPA between January 2007 and December 2008 was conducted. The CTPA images of all patients with a diagnosis of isolated SSPE were reviewed by a blinded thoracic radiologist. We reported the rate of agreement, with 95% confidence intervals (CI), of isolated SSPE diagnosis between radiologists. Other outcomes captured during follow-up included: recurrent venous thromboembolism (VTE), major bleeding episodes and overall mortality. All included patients were followed for three months.A total of 70 patients with a diagnosis of isolated SSPE (single or multiple) on were included. The median age was 64 (range 15–92) and 55% (39/70) were female. Twenty-six percent had a prior history of VTE. Forty-five percent of patients had cancer. The blinded thoracic radiologist agreed with 44% (31/70; 95% CI: 32% to 56%) of the initial isolated SSPE diagnoses. A total of 12% of the included CTPA images were interpreted by the thoracic radiologist to be without evidence of PE. Out of the 70 patients, 18 (26%) did not receive any anticoagulation, and none of them suffered recurrent VTE (PE or DVT) during the three-month follow-up period. One patient in the group of 55 patients who received anticoagulation (2%) suffered a major bleeding. A total of 33% (24/73) of patients died during the follow-up period, most of them from cancer progression. There was no fatal PE.The rate of agreement for the diagnosis of isolated SSPE on CTPA is moderate among radiologists. The risk-benefit ratio of anticoagulant therapy remains unclear in patients with SSPE, especially in the context of a modest agreement on the diagnosis. More prospective management studies and clinical trials are required to assess this very important clinical problem. Disclosures:No relevant conflicts of interest to declare.