Management of incidental pulmonary embolism

Implementation of an AI Algorithm in Clinical Practice to Reduce Missed Incidental Pulmonary Embolisms on Chest CT and Its Impact on Short-Term Survival

OBJECTIVES

A substantial number of incidental pulmonary embolisms (iPEs) in computed tomography scans are missed by radiologists in their daily routine. This study analyzes the radiological reports of iPE cases before and after implementation of an artificial intelligence (AI) algorithm for iPE detection. Furthermore, we investigate the anatomic distribution patterns within missed iPE cases and mortality within a 90-day follow-up in patients before and after AI use.

MATERIALS AND METHODS

This institutional review board-approved observational single-center study included 5298 chest computed tomography scans performed for reasons other than suspected pulmonary embolism (PE). We compared 2 cohorts: cohort 1, consisting of 1964 patients whose original radiology reports were generated before the implementation of an AI algorithm, and cohort 2, consisting of 3334 patients whose scans were analyzed after the implementation of an Food and Drug Administration-approved and CE-certified AI algorithm for iPE detection (Aidoc Medical, Tel Aviv, Israel). For both cohorts, any discrepancies between the original radiology reports and the AI results were reviewed by 2 thoracic imaging subspecialized radiologists. In the original radiology report and in case of discrepancies with the AI algorithm, the expert review served as reference standard. Sensitivity, specificity, prevalence, negative predictive value (NPV), and positive predictive value (PPV) were calculated. The rates of missed iPEs in both cohorts were compared statistically using STATA (Version 17.1). Kaplan-Meier curves and Cox proportional hazards models were used for survival analysis.

RESULTS

In cohort 1 (mean age 70.6 years, 48% female [n = 944], 52% male [n = 1020]), the prevalence of confirmed iPE was 2.2% (n = 42), and the AI detected 61 suspicious iPEs, resulting in a sensitivity of 95%, a specificity of 99%, a PPV of 69%, and an NPV of 99%. Radiologists missed 50% of iPE cases in cohort 1. In cohort 2 (mean age 69 years, 47% female [n = 1567], 53% male [n = 1767]), the prevalence of confirmed iPEs was 1.7% (56/3334), with AI detecting 59 suspicious cases (sensitivity 90%, specificity 99%, PPV 95%, NPV 99%). The rate of missed iPEs by radiologists dropped to 7.1% after AI implementation, showing a significant improvement ( P < 0.001). Most overlooked iPEs (61%) were in the right lower lobe. The survival analysis showed no significantly decreased 90-day mortality rate, with a hazards ratio of 0.95 (95% confidence interval, 0.45-1.96; P = 0.88).

CONCLUSIONS

The implementation of an AI algorithm significantly reduced the rate of missed iPEs from 50% to 7.1%, thereby enhancing diagnostic accuracy. Despite this improvement, the 90-day mortality rate remained unchanged. These findings highlight the AI tool's potential to assist radiologists in accurately identifying iPEs, although its implementation does not significantly affect short-term survival. Notably, most missed iPEs were located in the right lower lobe, suggesting that radiologists should pay particular attention to this area during evaluations.

Imaging of Acute Pulmonary Embolism: An Update

Imaging is essential in the evaluation and management of acute pulmonary embolism. Advances in multi-energy CT including dual-energy CT and photon-counting CT have allowed faster scans with lower radiation dose and optimal quality. Artificial intelligence has a potential role in triaging potentially positive examinations and could serve as a second reader.

Incidental venous thrombosis in oncology in a sub-Saharan tertiary hospital

The relationship between cancer and thrombosis was initially highlighted in the 19th century. Vascular complications in oncology can be arterial or venous thrombosis, and incidental pulmonary embolism is a growing challenge. We aimed to describe the frequency and clinical characteristics of cancer patients with incidental venous thromboembolism (iVTE). We conducted a descriptive study at the Yaounde General Hospital. We included patients with a confirmed diagnosis of cancer, followed up on an outpatient basis, in whom an iVTE was identified on a computed tomography scan performed to evaluate tumour status over a 6-month period. Of the 359 patients, 19 had venous thromboses, representing a frequency of 5.3%. The mean age was 51.2 years. The sex ratio was 1.1 in favour of males. Comorbidities found were diabetes, hypertension and obesity. Colon cancer (5), ovarian cancer (3) and lung cancer (3) were the most frequent diagnoses. All patients had advanced disease with 14 (73.7%) being naive to anticancer treatment. Pulmonary arteries were the most affected vessel (63.1%). The frequency of iVTE in a sub-Saharan context was around 5%.

Venous thromboembolism risk in amyotrophic lateral sclerosis: a hospital record-linkage study

BACKGROUND

Venous thromboembolism (VTE) can occur in amyotrophic lateral sclerosis (ALS) and pulmonary embolism causes death in a minority of cases. The benefits of preventing VTE must be weighed against the risks. An accurate estimate of the incidence of VTE in ALS is crucial to assessing this balance.

METHODS

This retrospective record-linkage cohort study derived data from the Hospital Episode Statistics database, covering admissions to England's hospitals from 1 April 2003 to 31 December 2019 and included 21 163 patients with ALS and 17 425 337 controls. Follow-up began at index admission and ended at VTE admission, death or 2 years (whichever came sooner). Adjusted HRs (aHRs) for VTE were calculated, controlling for confounders.

RESULTS

The incidence of VTE in the ALS cohort was 18.8/1000 person-years. The relative risk of VTE in ALS was significantly greater than in controls (aHR 2.7, 95% CI 2.4 to 3.0). The relative risk of VTE in patients with ALS under 65 years was five times higher than controls (aHR 5.34, 95% CI 4.6 to 6.2), and higher than that of patients over 65 years compared with controls (aHR 1.86, 95% CI 1.62 to 2.12).

CONCLUSIONS

Patients with ALS are at a higher risk of developing VTE, but this is similar in magnitude to that reported in other chronic neurological conditions associated with immobility, such as multiple sclerosis, which do not routinely receive VTE prophylaxis. Those with ALS below the median age of symptom onset have a notably higher relative risk. A reappraisal of the case for routine antithrombotic therapy in those diagnosed with ALS now requires a randomised controlled trial.

Mortality, Recurrent Thromboembolism and Major Bleeding in Cancer-Associated and Non-Cancer Pulmonary Embolism Patients Treated With Direct Oral Anticoagulants

BACKGROUND

Pulmonary embolism (PE) is a potentially fatal form of venous thromboembolism (VTE). This study compares the mortality, incidence of recurrent VTE, and incidence of major bleeding between non-cancer and cancer-associated PE patients treated with direct oral anticoagulants (DOACs).

METHODS AND RESULTS

This was a retrospective, observational, single-center study involving 130 consecutive patients (87 with active cancer; 43 without cancer) who received DOAC treatment for PE between January 2016 and December 2019. Kaplan-Meier analysis showed significantly higher mortality in cancer-associated PE patients than in non-cancer patients (35/87 [40%] vs. 1/43 [2%], P<0.001, log-rank test, HR 18.6 [95% CI: 2.5-136.0]). In contrast, the cumulative incidences of recurrent VTE and major bleeding were comparable between the 2 groups. Among the cancer-associated PE patients, the incidence for the composite outcome of recurrent VTE or major bleeding was significantly higher in patients undergoing chemotherapy than in those not undergoing chemotherapy (9/37 [24%] vs. 2/50 [4%], P=0.004, log-rank test, HR 6.9 [95% CI: 1.5-32.0]).

CONCLUSIONS

Although cancer-associated PE patients treated with DOACs showed higher mortality compared with non-cancer patients, presumably because of the presence of cancer, the risk of recurrent VTE or major bleeding was comparable between the 2 groups. Thus, DOAC is an important treatment option for cancer-associated PE, although underlying cancer-related risks (e.g., chemotherapy) remain.

Rivaroxaban treatment for asymptomatic venous thromboembolism: insights from the J'xactly study

BACKGROUND

An established treatment strategy for asymptomatic pulmonary embolism (PE) or deep vein thrombosis (DVT) remains uncertain in Japan; therefore, in this study, we clarify the characteristics and outcomes of symptomatic compared to asymptomatic patients with PE or DVT.

METHODS

This prospective, multicenter sub-analysis of the J'xactly study in Japan included 1,016 patients (mean age, 68; 41% male) with venous thromboembolism (VTE) treated with rivaroxaban.

RESULTS

Asymptomatic PE patients (47% of PE patients) were more likely to have active cancer and asymptomatic proximal DVT at lower severity than symptomatic PE patients, despite no differences in age, sex, or the proportion receiving intensive 30 mg/day-rivaroxaban. Patients with asymptomatic DVT (34% of DVT patients) were older, had higher rates of female sex, active cancer, and distal DVT, and received shorter, less intense rivaroxaban treatment. Incidences did not differ between asymptomatic and symptomatic PE patients for recurrent symptomatic VTE (hazard ratio [HR], 0.60; 95% confidence interval [CI], 0.22-1.62; P = 0.31) or major bleeding (HR, 0.68; 95% CI, 0.20-2.33; P = 0.58), nor between asymptomatic and symptomatic DVT patients for recurrent symptomatic VTE (HR, 0.56; 95% CI, 0.23-1.40; P = 0.21) and major bleeding (HR, 1.47; 95% CI, 0.54-3.97; P = 0.45).

CONCLUSIONS

The real-world composite adverse event rate for treatment with rivaroxaban, as physician-adjusted for dose and duration, was similar for asymptomatic and symptomatic patients regardless of the presence of PE or DVT, suggesting a favorable safety profile for potential rivaroxaban treatment for asymptomatic VTE.

Prognosis of incidental pulmonary embolism vs. symptomatic pulmonary embolism in cancer patients: a single-center retrospective cohort study in China

BACKGROUND

The incidence of incidental pulmonary embolism (IPE) has greatly increased, but its clinical characteristics and outcomes are still controversial. This study aimed to compare the clinical characteristics and outcomes between cancer patients with IPE and patients with symptomatic pulmonary embolism (SPE).

PATIENTS/METHODS

Clinical data of 180 consecutive patients with cancer complicated with pulmonary embolism admitted to Beijing Cancer Hospital from July 2011 to December 2019 were retrospectively collected and analysed. General characteristics, diagnosis time of pulmonary embolism (PE), location of PE, concurrent deep venous thrombosis, anticoagulant treatment, impact of PE on anti-tumor treatment, recurrent venous thromboembolism, rate of bleeding after anticoagulation therapy, survival and risk factors of IPE were compared with SPE.

RESULTS

Of 180 patients, 88 (49%) had IPEs and 92 (51%) had SPEs. Patients with IPE and SPE did not differ in age, sex, tumor type, or tumor stage. Median diagnosis times of IPE and SPE after cancer were 108 (45, 432) days and 90 (7, 383) days, respectively. Compared to SPE, IPE tended to be central (44% versus 26%; P < 0.001), isolated (31.8% versus 0.0%; P < 0.001), and unilateral (67.1% versus 12.8%; P < 0.00). The rate of bleeding after anticoagulation therapy did not differ between IPE and SPE. Patients with IPE had a better prognosis than patients with SPE in terms of 30-, and 90-day mortality, as well as overall survival after diagnosis of PE (median: 314.5 vs. 192.0 days, log-rank P = 0.004) and cancer (median: 630.0 vs. 450.5 days, log-rank P = 0.018). SPE (compared to IPE) was an independent risk factor for poor survival after diagnosis of PE in multivariate analysis (hazard ratio [HR] = 1.564, 95% confidence interval [CI]: 1.008-2.425, p = 0.046).

CONCLUSIONS

IPE accounts for nearly one half of PE cases among Chinese cancer patients. With active anticoagulation treatment, IPE is expected to achieve better survival rates than SPE.

Artificial Intelligence Tool for Detection and Worklist Prioritization Reduces Time to Diagnosis of Incidental Pulmonary Embolism at CT

Purpose

To evaluate the diagnostic efficacy of artificial intelligence (AI) software in detecting incidental pulmonary embolism (IPE) at CT and shorten the time to diagnosis with use of radiologist reading worklist prioritization.

Materials and Methods

In this study with historical controls and prospective evaluation, regulatory-cleared AI software was evaluated to prioritize IPE on routine chest CT scans with intravenous contrast agent in adult oncology patients. Diagnostic accuracy metrics were calculated, and temporal end points, including detection and notification times (DNTs), were assessed during three time periods (April 2019 to September 2020): routine workflow without AI, human triage without AI, and worklist prioritization with AI.

Results

In total, 11 736 CT scans in 6447 oncology patients (mean age, 63 years ± 12 [SD]; 3367 men) were included. Prevalence of IPE was 1.3% (51 of 3837 scans), 1.4% (54 of 3920 scans), and 1.0% (38 of 3979 scans) for the respective time periods. The AI software detected 131 true-positive, 12 false-negative, 31 false-positive, and 11 559 true-negative results, achieving 91.6% sensitivity, 99.7% specificity, 99.9% negative predictive value, and 80.9% positive predictive value. During prospective evaluation, AI-based worklist prioritization reduced the median DNT for IPE-positive examinations to 87 minutes (vs routine workflow of 7714 minutes and human triage of 4973 minutes). Radiologists' missed rate of IPE was significantly reduced from 44.8% (47 of 105 scans) without AI to 2.6% (one of 38 scans) when assisted by the AI tool (P < .001).

Conclusion

AI-assisted workflow prioritization of IPE on routine CT scans in oncology patients showed high diagnostic accuracy and significantly shortened the time to diagnosis in a setting with a backlog of examinations.Keywords: CT, Computer Applications, Detection, Diagnosis, Embolism, Thorax, ThrombosisSupplemental material is available for this article.© RSNA, 2023See also the commentary by Elicker in this issue.

Detection of Incidental Pulmonary Embolism on Conventional Contrast-Enhanced Chest CT: Comparison of an Artificial Intelligence Algorithm and Clinical Reports

BACKGROUND. Artificial intelligence (AI) algorithms have shown strong performance for detection of pulmonary embolism (PE) on CT examinations performed using a dedicated protocol for PE detection. AI performance is less well studied for detecting PE on examinations ordered for reasons other than suspected PE (i.e., incidental PE [iPE]). OBJECTIVE. The purpose of this study was to assess the diagnostic performance of an AI algorithm for detection of iPE on conventional contrast-enhanced chest CT examinations. METHODS. This retrospective study included 2555 patients (mean age, 53.2 ± 14.5 [SD] years; 1340 women, 1215 men) who underwent 3003 conventional contrast-enhanced chest CT examinations (i.e., not using pulmonary CTA protocols) between September 2019 and February 2020. A commercial AI algorithm was applied to the images to detect acute iPE. A vendor-supplied natural language processing (NLP) algorithm was applied to the clinical reports to identify examinations interpreted as positive for iPE. For all examinations that were positive by the AI-based image review or by NLP-based report review, a multireader adjudication process was implemented to establish a reference standard for iPE. Images were also reviewed to identify explanations of AI misclassifications. RESULTS. On the basis of the adjudication process, the frequency of iPE was 1.3% (40/3003). AI detected four iPEs missed by clinical reports, and clinical reports detected seven iPEs missed by AI. AI, compared with clinical reports, exhibited significantly lower PPV (86.8% vs 97.3%, p = .03) and specificity (99.8% vs 100.0%, p = .045). Differences in sensitivity (82.5% vs 90.0%, p = .37) and NPV (99.8% vs 99.9%, p = .36) were not significant. For AI, neither sensitivity nor specificity varied significantly in association with age, sex, patient status, or cancer-related clinical scenario (all p > .05). Explanations of false-positives by AI included metastatic lymph nodes and pulmonary venous filling defect, and explanations of false-negatives by AI included surgically altered anatomy and small-caliber subsegmental vessels. CONCLUSION. AI had high NPV and moderate PPV for iPE detection, detecting some iPEs missed by radiologists. CLINICAL IMPACT. Potential applications of the AI tool include serving as a second reader to help detect additional iPEs or as a worklist triage tool to allow earlier iPE detection and intervention. Various explanations of AI misclassifications may provide targets for model improvement.

Clinical Characteristics, Risk Factors, and Outcomes of Acute Pulmonary Embolism in Asian Population

BACKGROUND

Acute pulmonary embolism (APE) is a common condition with increasing worldwide incidence. However, the clinical characteristics, risk factors, and clinical outcomes of APE in the Asian population especially in the Thai population are still limited. Therefore, the objective of this study was to identify the clinical characteristics, risk factors, and clinical outcomes of APE in the Asian population.

METHODS

A cross-sectional study was conducted on patients diagnosed with APE at Chiang Mai University Hospital, Thailand during 2011-2020.

RESULTS

During the study period, 696 patients confirmed the diagnosis of APE with a mean age of 57.7 ± 15.7 years and 41.1% males. APE was suspected in 468 of 696 patients (67.2%), while 228 patients (32.8%) had incidental PE. Active malignancy during treatment was found in 388 (55.7%). Dyspnea, cough, and chest pain were the most common presenting symptoms. Respiratory failure was found in 129 patients (18.6%). The thirty-day all-cause mortality rate was 19.1%. PE-related mortality was 5.6%. Most PE-related mortality was high-risk PE.

CONCLUSION

APE was not uncommon in the Asian population. Active cancer, especially lung cancer was the most common risk factors. High-risk and intermediate-high-risk PE were associated with high mortality. Risk stratification and prompt management are warranted to improve outcomes.

Cancer patients' experiences of the diagnosis and treatment of incidental pulmonary embolism (a qualitative study)

BACKGROUND

The diagnosis of symptomatic cancer-associated thrombosis often causes distress and alarm for patients, especially for those unaware of the risk, or the signs and symptoms to look out for. There are few data about cancer patients' experiences of incidentally diagnosed pulmonary embolism (IPE), where lack of warning (recognised signs, symptoms) may cause delayed diagnosis and aggravate distress.

OBJECTIVES

To explore cancer patients' experience of the diagnosis of and living with incidental pulmonary embolism treated with anticoagulation.

METHODS

A qualitative study using modified grounded theory approach. Semi-structured interviews were conducted as part of a mixed- methods prospective observational survey study of consenting patients with IPE. Data were subjected to thematic analysis. The qualitative findings are presented.

FINDINGS

Eleven participants were interviewed (mean age 68.3 years, range 38-82 years; various forms of cancer and stages). Three major themes and one cross-cutting theme were generated. Theme (1): IPE is experienced in the context of cancer and concomitant comorbidities. Issues are understood in the shadow of-and often overshadowed by-current serious illness. Theme (2): Being diagnosed with IPE. Misattribution to cancer or other comorbidities caused delay in help-seeking and diagnosis. Theme (3): Coping with anticoagulation. Participants' incorporated anticoagulation treatment and its effects into their daily routine with acceptance and stoicism. Finally, the cross-cutting theme relates to a lack of information and uncertainty, contributing to distress throughout the experience.

CONCLUSION

The diagnosis of IPE was upsetting and unexpected. Expert and timely information was valued by those with IPE. Education called for about the increased risk of cancer-associated thrombosis and the signs and symptoms to be aware of.

Incidental pulmonary embolism in cancer and noncancer patients: Prospective cohort study

BACKGROUND

Clinical picture and outcome of incidental pulmonary embolism (iPE) compared to symptomatic pulmonary embolism (sPE) remain unclear.

METHODS

Demographics, recurrent venous thromboembolism (VTE), mortality, major bleeding, and clinically relevant nonmajor bleeding (CRNMB) were compared between iPE and sPE patients who were followed prospectively at Mayo Thrombophilia Clinic (March 1, 2013 to August 1, 2020).

RESULTS

Out of 3576 VTE patients, 1417 (39.6%) had PE: 562 (39.7%) iPE and 855 sPE. Patients with cancer were more likely to have iPE (400 iPE vs. 314 sPE) compared to those without cancer (162 iPE vs. 541 sPE). VTE recurrence rate (all per 100 person-years) was similar in all iPE and sPE patients (3.34 vs. 3.68, p = .50), with cancer (4.16 vs. 4.89, p = .370), and without cancer patients (0.89 vs. 2.80, p = .25). Higher mortality observed in all patients with iPE compared to sPE (46.45 vs. 23.47, p < .001) and with cancer (56.41 vs. 45.77, p = .03) became not significant after adjustment for age, antiplatelet therapy, metastases, and cancer location. Noncancer iPE patients had higher mortality (15.95 vs. 7.18, p = .006) even after adjustment (p = .05). The major bleeding rate was also higher in all patients iPE compared to sPE (7.10 vs. 3.68, p = .03), but not after adjustment (p = .974); higher major bleeding rate in noncancer patients (6.49 vs. 1.25, p = .007) remained significant after adjustment (.02). CRNMB rate was similar to iPE and sPE patients.

CONCLUSION

iPE represents a more serious clinical condition compared to sPE as indicated by the higher mortality and major bleeding but these differences reflect underlying comorbidities rather than the seriousness of the embolic event.

Acute Pulmonary Embolism: A Review

IMPORTANCE

Pulmonary embolism (PE) is characterized by occlusion of blood flow in a pulmonary artery, typically due to a thrombus that travels from a vein in a lower limb. The incidence of PE is approximately 60 to 120 per 100 000 people per year. Approximately 60 000 to 100 000 patients die from PE each year in the US.

OBSERVATIONS

PE should be considered in patients presenting with acute chest pain, shortness of breath, or syncope. The diagnosis is determined by chest imaging. In patients with a systolic blood pressure of at least 90 mm Hg, the following 3 steps can be used to evaluate a patient with possible PE: assessment of the clinical probability of PE, D-dimer testing if indicated, and chest imaging if indicated. The clinical probability of PE can be assessed using a structured score or using clinical gestalt. In patients with a probability of PE that is less than 15%, the presence of 8 clinical characteristics (age <50 years, heart rate <100/min, an oxygen saturation level of > 94%, no recent surgery or trauma, no prior venous thromboembolism event, no hemoptysis, no unilateral leg swelling, and no estrogen use) identifies patients at very low risk of PE in whom no further testing is needed. In patients with low or intermediate clinical probability, a D-dimer level of less than 500 ng/mL is associated with a posttest probability of PE less than 1.85%. In these patients, PE can be excluded without chest imaging. A further refinement of D-dimer threshold is possible in patients aged 50 years and older, and in patients with a low likelihood of PE. Patients with a high probability of PE (ie, >40% probability) should undergo chest imaging, and D-dimer testing is not necessary. In patients with PE and a systolic blood pressure of 90 mm Hg or higher, compared with heparin combined with a vitamin K antagonist such as warfarin followed by warfarin alone, direct oral anticoagulants such as apixaban, edoxaban, rivaroxaban, or dabigatran, are noninferior for treating PE and have a 0.6% lower rate of bleeding. In patients with PE and systolic blood pressure lower than 90 mm Hg, systemic thrombolysis is recommended and is associated with an 1.6% absolute reduction of mortality (from 3.9% to 2.3%).

CONCLUSIONS AND RELEVANCE

In the US, PE affects approximately 370 000 patients per year and may cause approximately 60 000 to 100 000 deaths per year. First-line therapy consists of direct oral anticoagulants such as apixaban, edoxaban, rivaroxaban, or dabigatran, with thrombolysis reserved for patients with systolic blood pressure lower than 90 mm Hg.

Concomitant Deep Vein Thrombosis in Cancer Patients with Unsuspected Pulmonary Embolism

Simple Summary

Cancer patients have a significantly higher risk of developing venous thromboembolism during their disease course when compared with the general population. During routine staging or follow-up imaging studies, incidental venous thromboemboli, including incidental pulmonary embolisms, can be identified. Identifying factors associated with incidental or unsuspected venous thromboembolism is important and can improve the management plan. In the current study, we found that 20.9% of patients with unsuspected pulmonary embolisms had concomitant deep vein thrombosis, and most of these patients were asymptomatic. In addition, we found that concomitant deep vein thrombosis increases the odds of venous thrombosis recurrence in cancer patients presenting with unsuspected pulmonary emboli. Therefore, for patients with isolated incidental subsegmental pulmonary embolism and concomitant deep vein thrombosis, initiating anticoagulants if no contraindications exist is recommended. In addition, the presence of concomitant deep vein thrombosis among cancer patients with unsuspected pulmonary embolisms is associated with poor short- and long-term outcomes in these patients.

Abstract

Incidental venous thromboembolism (VTE) is common in cancer patients and identifying factors associated with these events can improve the management plan. We studied the characteristics of concomitant deep vein thrombosis (C-DVT) in cancer patients presenting with unsuspected pulmonary embolism (PE) and the association of C-DVT with VTE recurrence and survival outcomes. Patients presenting to our emergency department with confirmed unsuspected/incidental PE between 1 January 2006 and 1 January 2016, were identified. Radiologic reports were reviewed to confirm the presence or absence of C-DVT. Logistic regression analyses and cox regression modeling were used to determine the effect of C-DVT on VTE recurrence and survival outcomes. Of 904 eligible patients, 189 (20.9%) had C-DVT. Patients with C-DVT had twice the odds of developing VTE recurrence (odds ratio 2.07, 95% confidence interval 1.21–3.48, p = 0.007). The mortality rates among C-DVT were significantly higher than in patients without. C-DVT was associated with reduced overall survival in patients with unsuspected PE (hazard ratio 1.33, 95% confidence interval 1.09–1.63, p = 0.005). In conclusion, C-DVT in cancer patients who present with unsuspected PE is common and is associated with an increased risk of VTE recurrence and poor short- and long-term survival. Identifying other venous thrombi in cancer patients presenting with unsuspected PE is recommended and can guide the management plan. For patients with isolated incidental subsegmental pulmonary embolism and concomitant deep vein thrombosis, initiating anticoagulants if no contraindications exist is recommended.

Emergency management of incidental pulmonary embolism (IPE)

Venous thrombo-embolic (VTE) disease is a common cause of complications in patients with cancer and is the second most common cause of death in oncology patients other than the malignant disease. Whilst symptomatic VTE comprises the majority of such presentations to an emergency department (ED), incidental pulmonary embolism (IPE) is an increasingly frequent reason for attendance.

Many studies report that the consequences of IPE do not differ significantly from those with symptomatic presentations and thus most guidelines recommend using the same approach. The complexity of treatment in cancer patients due to increased prevalence of co-morbidities, higher risk of bleeding, abnormal platelet and renal function, greater risk of VTE recurrence, and medications with the risk of anticoagulant interaction are consistent across patients with symptomatic and IPE.

One of the initial challenges of the management of IPE is the design of a pathway that provides both patients and clinicians with a seamless journey from the radiological diagnosis of IPE to their initial clinical workup and management. Increased access to ambulatory care has successfully reduced ED utilisation and improved clinical outcomes in high-risk non-oncological populations, such as those with IPE.

In this clinical review, we consider IPE management, its workup, the conundrums it may present for emergency physicians and the need to consider emergency ambulatory care for this growing cohort of patients.

Pitfalls in the imaging of pulmonary embolism

Pulmonary embolism (PE) can present with a wide spectrum of clinical symptoms that can overlap considerably with other cardiovascular diseases. To avoid PE related morbidity and mortality, it is vital to identify this disease accurately and in a timely fashion. Several clinical criteria have been developed to standardize the diagnostic approach for patients with suspected PE. Computed tomographic pulmonary angiogram has significantly improved the detection of pulmonary embolism and is considered the imaging modality of choice to diagnose this disease. However, there are several potential pitfalls associated with this modality which can make diagnosis of PE challenging. In this review, we will discuss various pitfalls routinely encountered in the diagnostic work up of patients with suspected PE, approaches to mitigate these pitfalls and incidental pulmonary embolism.

Usefulness of a refined computed tomography imaging method to assess the prevalence of residual pulmonary thrombi in patients 1 year after acute pulmonary embolism: The Nagoya PE study

BACKGROUND

Post-pulmonary embolism (PE) syndrome is an important clinical condition that can affect the long-term prognosis after acute PE.

OBJECTIVE

We aimed to evaluate the prevalence of residual pulmonary thrombi and the thrombotic burden 1 year after acute PE, by using our refined computed tomography (CT) imaging method.

PATIENTS/METHODS

In this prospective study, patients diagnosed with acute PE were recruited and examinations were conducted at 1 month, 6 months, and 1 year. Especially at 1 year, patients were evaluated multifacetedly, including by laboratory tests, quality-of-life, 6-min walking test, and enhanced CT.

RESULTS

Fifty-two patients were enrolled. Two patients (3.8%) developed chronic thromboembolic pulmonary hypertension. A total of 43 patients completed evaluation at 1 year, among whom (74%) had residual thrombi, with a median modified CT obstruction index (mCTOI) of 10.7%. In multivariate analysis, residual thrombi at 1 month was the only factor significantly related to residual thrombi at 1 year (odds ratio, 103.4; 95% confidence interval, 4.2-2542.1). The tricuspid regurgitation pressure gradient ≥60 mmHg and left ventricular end-diastolic dimension at diagnosis were significantly related to mCTOI at 1 year (β = 0.367, P = .003; and β = -0.435, P = .001, respectively).

CONCLUSIONS

Using our improved CT imaging protocol, we found a high prevalence of residual thrombi 1 year after acute PE. Furthermore, right ventricular overload was related to the thrombotic burden. The long-term treatment strategy of acute PE could be modified to include precise CT imaging.

Automated detection of pulmonary embolism from CT-angiograms using deep learning

Background

The aim of this study was to develop and evaluate a deep neural network model in the automated detection of pulmonary embolism (PE) from computed tomography pulmonary angiograms (CTPAs) using only weakly labelled training data.

Methods

We developed a deep neural network model consisting of two parts: a convolutional neural network architecture called InceptionResNet V2 and a long-short term memory network to process whole CTPA stacks as sequences of slices. Two versions of the model were created using either chest X-rays (Model A) or natural images (Model B) as pre-training data. We retrospectively collected 600 CTPAs to use in training and validation and 200 CTPAs to use in testing. CTPAs were annotated only with binary labels on both stack- and slice-based levels. Performance of the models was evaluated with ROC and precision–recall curves, specificity, sensitivity, accuracy, as well as positive and negative predictive values.

Results

Both models performed well on both stack- and slice-based levels. On the stack-based level, Model A reached specificity and sensitivity of 93.5% and 86.6%, respectively, outperforming Model B slightly (specificity 90.7% and sensitivity 83.5%). However, the difference between their ROC AUC scores was not statistically significant (0.94 vs 0.91, p = 0.07).

Conclusions

We show that a deep learning model trained with a relatively small, weakly annotated dataset can achieve excellent performance results in detecting PE from CTPAs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12880-022-00763-z.

Pharmacological and interventional management of pulmonary embolism: where do we stand?

As the third most common cardiovascular disease, pulmonary embolism (PE) has an uptrending incidence and mortality, resulting in significant healthcare expenditure. Risk stratification of acute PE guides management. Although anticoagulation remains the cornerstone management, systemic fibrinolysis and targeted therapeutic approaches, catheter-directed thrombolysis and catheter-based embolectomy are available for high-risk patients. Life-threatening bleeding complications associated with systemic fibrinolysis have restricted its widespread implementation. Catheter-based techniques for intermediate high-risk categories were devised to reduce bleeding complications and improve outcomes. Catheter-directed thrombolysis helps minimize bleeding by way of direct drug delivery. Catheter-based embolectomy mechanically retrieves thrombi without using fibrinolytics. This focused review of medical and interventional management of acute PE provides a highlight of ongoing trials expected to add value to current practice.

Prognostic Performance of Hestia Criteria in Acute Pulmonary Embolism: A Systematic Review and Meta-Analysis

Previous studies have suggested that Hestia criteria could effectively identifying patients with acute pulmonary embolism (PE) who were at low risk of mortality for outpatient treatment or early discharge. But the performance of Hestia criteria in stratifying patients at different risk class is still unknown. We sought to comprehensively evaluate the prognostic impact of Hestia criteria for PE. The literatures search was conducted in PubMed, Web of Science and EMBASE from 1 August 2011 to 31 October 2021. Finally, Eight studies with 4110 patients were included in our meta-analysis. Overall, the pool percentage of patients classified as low-risk group and high-risk group were 41.4%% and 58.6% respectively, and the all-course mortality rates of each group were 2.3% and 10.6%, respectively. The pooled rate of PE-related composite adverse outcomes in high-risk group was increasingly higher than in low-risk group (15.7% vs 4.4%). High risk group was also markedly associated with overall mortality (OR: 7.21, 95%CI: 4.96-10.46, p < 0.00001), and PE-related adverse outcomes (OR:5.38, 95% CI:3.95-7.32, p < 0.00001). The pooled sensitivity, specificity, PLR, NLR of Hestia criteria for overall mortality were 0.90 (95% CI:0.83-0.94), 0.43 (95% CI:0.31-0.55), 1.6 (95% CI:1.3-1.9), 0.23 (95% CI: 0.15-0.35), respectively. The area under SROC curve (AUC) was 0.81 (95% CI: 0.77-0.84). The result of our meta-analysis indicate that Hestia criteria can effectively identify PE patients at low risk of poor prognosis with high sensitivity and NPV, but its prognostic role in patients with higher risk class still need to be verified.

Symptomatic pulmonary embolus after catheter removal in children with catheter related thrombosis: A report from the CHAT Consortium

BACKGROUND

Appropriate timing of central venous catheter (CVC) removal, in relation to start of anticoagulation, in children after the diagnosis of a CVC-related thrombosis (CRT) is not well established.

OBJECTIVES

This retrospective cohort study evaluated the incidence of symptomatic pulmonary embolism (PE) after CVC removal using data from the multi-institutional Children's Hospital-Acquired Thrombosis (CHAT) Consortium Registry.

PATIENTS/METHODS

The CHAT Registry consists of data from children aged 0-21 years with a hospital-acquired venous thromboembolism. Eligible subjects were those with CRT diagnosed <3 days after CVC removal. Subjects were excluded if the CRT was due to a failed CVC insertion. Subjects were divided into three groups: those with CVC removal without anticoagulation, those with CVC removal <48 h after starting anticoagulation, and those with CVC removal ≥48 h after starting anticoagulation.

RESULTS

A total of 687 CRT events from 663 subjects were included. A majority of CRT events were in subjects with peripherally inserted central catheters (62.3%, n = 428). For the 611 CRT events in which the CVC was removed, there was only one case of symptomatic PE (0.16%), which occurred <48 h after initiation of anticoagulation.

CONCLUSIONS

While current guidelines suggest anticoagulation before CVC removal in the setting of a CRT to prevent embolization, CVC removal is not associated with symptomatic PE regardless of duration of anticoagulation before CVC removal.

Concurrence of Gastric Cancer and Incidental Pulmonary Embolism May Be a Prognostic Factor for Advanced Gastric Cancer Patients with Incidental Pulmonary Embolism

Objective

Cancer is well known as the most important risk factor for the emergence of pulmonary embolism (PE). The incidence of incidental PE (IPE) has increased with widely use of multi-detector-row computed tomography (CT) technology. Simultaneously, more new cancer patients diagnosed concomitantly with IPE are found. No study has examined the presentation and prognosis of incidental pulmonary embolism (IPE) in gastric cancer patients. The aim of this study was to analyse prognostic factors in patients with advanced gastric cancer complicated with IPE.

Patients and Methods

Ninety patients with histologically confirmed advanced gastric adenocarcinoma diagnosed with IPE were enrolled. Continuous variables were compared using Student’s t-test or the Mann–Whitney U-test if non-normally distributed. The Chi-squared test (or Fisher’s exact test where appropriate) was used to compare categorical variables. The Kaplan–Meier method and the Log rank test were used for survival analysis. Independent prognostic factors for survival were determined using a Cox proportional hazards model. A two-sided P-value < 0.05 was considered statistically significant.

Results

Nineteen patients were diagnosed with IPE concomitantly with gastric cancer. Concurrence of gastric cancer and IPE, lack of anticoagulation therapy, and location of IPE were associated with survival. After adjusting for age and sex, the concurrence of gastric cancer and IPE, lack of anticoagulation, and central IPE independently influenced the survival of advanced gastric cancer patients with IPE. Subgroup analysis of patients with peripheral pulmonary embolisms confirmed that anticoagulant therapy provided a survival benefit.

Conclusion

Concurrence of gastric cancer and IPE may be a prognostic factor for advanced gastric cancer patients with IPE.

Clinical characteristics, management, and outcome of incidental pulmonary embolism in cancer patients

Incidental pulmonary embolisms (IPEs) are common in cancer patients. Examining the characteristics and outcomes of IPEs in cancer patients can help to ensure proper management, promoting better outcomes. To determine the clinical characteristics, management, and outcomes of IPEs for cancer patients, we conducted a 1:2 ratio case-control study and identified all consecutive patients with IPE who visited the emergency department at The University of Texas MD Anderson Cancer Center between 1 January 2006 and 1 January 2016. Each IPE case was matched with 2 controls using a propensity score obtained using logistic regression for IPE status with other factors affecting overall survival. A total of 904 confirmed cases were included in the analysis. IPE frequently occurred during the first year after cancer diagnosis (odds ratio [OR], 2.79; 95% confidence interval [95% CI], 2.37-3.29; P < .001). Patients receiving cytotoxic chemotherapy had a nearly threefold greater risk of developing IPE (OR, 2.87; 95% CI, 2.42-3.40; P < .001). In-hospital mortality was 1.9%. The 7- and 30-day mortality rates among the cases were 1.8% and 9.9%, respectively, which was significantly higher than in the control groups: 0.2% and 3.1%, respectively (P < .001). IPE was associated with reduced overall survival (hazard ratio [HR], 1.93; 95% CI, 1.74-2.14; P < .001). Concurrent incidental venous thromboembolism was identified in 189 of the patients (20.9%) and was also associated with reduced overall survival (HR, 1.65; 95% CI, 1.21-2.25; P = .001). Our results show that IPE events are associated with poor outcomes in cancer patients. Proper management plans similar to those of symptomatic pulmonary embolisms are essential.

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.

Clinical Outcomes of Incidental Venous Thromboembolism in Cancer and Noncancer Patients: The SWIss Venous ThromboEmbolism Registry (SWIVTER)

OBJECTIVE

 In patients with cancer-associated venous thromboembolism (VTE), the risk of recurrence is similar after incidental and symptomatic events. It is unknown whether the same applies to incidental VTE not associated with cancer.

METHODS AND RESULTS

 We compared baseline characteristics, anticoagulation therapy, all-cause mortality, and VTE recurrence rates at 90 days between patients with incidental (n = 131; 52% without cancer) and symptomatic (n = 1,931) VTE included in the SWIss Venous ThromboEmbolism Registry (SWIVTER). After incidental VTE, 114 (87%) patients received anticoagulation therapy for at least 3 months. The mortality rate was 9.2% after incidental and 8.4% after symptomatic VTE for hazard ratio (HR) 1.10 (95% confidence interval [CI] 0.49-2.50). After adjustment for competing risk of death, recurrence rate was 3.1 versus 2.8%, respectively, for sub-HR 1.07 (95% CI 0.39-2.93). These results were consistent among cancer (mortality: 15.9% vs. 12.6%; HR 1.32, 95% CI 0.67-2.59; recurrence: 4.8% vs. 4.7%; HR 1.02, 95% CI 0.30-3.42) and noncancer patients (mortality: 2.9% vs. 2.1%; HR 1.37, 95% CI 0.33-5.73; recurrence: 1.5% vs. 2.3%; HR 0.63, 95% CI 0.09-4.58). Patients with incidental VTE who received anticoagulation therapy for at least 3 months had lower mortality (4% vs. 41%) and recurrence rate (1% vs. 18%) compared with those who did not.

CONCLUSION

 In SWIVTER, more than half of incidental VTE events occurred in noncancer patients who often received anticoagulation therapy. Among noncancer patients, early mortality and recurrence rates were similar after incidental versus symptomatic VTE. Our findings suggest that anticoagulation therapy for incidental VTE may be beneficial regardless of the presence of cancer.

Challenging anticoagulation cases: A case of incidental subsegmental pulmonary embolism in a patient with cancer

Cancer therapy and progress in quality of imaging technologies for cancer surveillance and staging are in cause for the increase incidence of smaller incidental pulmonary embolism (PE). The clinical significance of incidental subsegmental pulmonary embolism (SSPE) is hard to define, balancing between possible false positive result, hypercoagulability signal, and truly venous thromboembolism (VTE) event. Evidence for optimal management of such findings are largely extrapolated from symptomatic SSPE in non-cancer patients and from symptomatic, more proximal PE in cancer patients. Current practice guidelines vary but some suggest withholding anticoagulation in selected patients. However, most SSPEs, incidental or not, should be treated as any other cancer-associated PE due to likely similar prognosis. Choice and duration of anticoagulation are extended from existing knowledge on more proximal PE.

Risk of Venous Thromboembolism After Hospital Discharge in Patients With Inflammatory Bowel Disease: A Population-based Study

BACKGROUND

Inflammatory bowel disease (IBD) is associated with a high risk of venous thromboembolism (VTE) during hospitalization. It is unclear if this association persists after discharge. We aimed to assess the incidence of postdischarge VTE in IBD patients and to determine if IBD is associated with increased VTE risk.

METHODS

We performed a population-based cohort study between 2002 and 2016 using Ontario health administrative data sets. Hospitalized (≥72 hours) adults with IBD were stratified into nonsurgical and surgical cohorts and matched on propensity score to non-IBD controls. Time to postdischarge VTE was assessed by Kaplan-Meier methods, and VTE risk was assessed by Cox proportional hazard models.

RESULTS

A total of 81,900 IBD discharges (62,848 nonsurgical and 19,052 surgical) were matched to non-IBD controls. The cumulative incidence of VTE at 12 months after discharge was 2.3% for nonsurgical IBD patients and 1.6% for surgical IBD patients. The incidence increased in the nonsurgical IBD cohort by 4% per year (incidence rate ratio, 1.04; 95% CI, 1.02-1.05). In our propensity score-matched analysis, the risk of VTE at 1-month postdischarge was greater in nonsurgical IBD patients (hazard ratio [HR], 1.72; 95% CI, 1.51-1.96) and surgical patients with ulcerative colitis (HR, 1.68; 95% CI, 1.16-2.45) but not surgical patients with Crohn's disease. These trends persisted through 12 months.

CONCLUSIONS

Nonsurgical IBD patients and surgical patients with ulcerative colitis are 1.7-fold more likely to develop postdischarge VTE than non-IBD patients. These findings support the need for increased vigilance and consideration of thromboprophylaxis in this population.

Incidental pulmonary embolism in oncologic patients-a systematic review and meta-analysis

Purpose

Incidental pulmonary embolism (IPE) is a common finding on computed tomography (CT). IPE is frequent in oncologic patients undergoing staging CT. The aim of this analysis was to provide the pooled frequency of IPE and frequencies of IPE in different primary tumors.

Methods

MEDLINE, SCOPUS, and EMBASE databases were screened for studies investigating frequency of IPE in oncologic staging CT up to February 2020. Overall, 12 studies met the inclusion criteria and were included into the present study.

Results

The pooled analysis yielded a total of 28,626 patients. IPE was identified in 963 patients (3.36%, 95% CI = 3.15; 3.57). The highest frequency was found in prostate cancer (8.59%, 95%CI = 3.74; 13.44), followed by hepatobiliary carcinoma (6.07%, 95%CI = 3.09; 9.05) and pancreatic cancer (5.65%, 95%CI = 3.54; 7.76). The lowest frequencies were identified in tumors of male reproductive organs (0.79%, 95%CI = 0.21; 1.37) and hematological diseases (1.11% 95%CI = 0.74; 1.48).

Conclusion

The overall frequency of IPE in oncologic patients was 3.36%. There are considerable differences in regard to primary tumors with the highest frequency in prostate cancer and pancreatic and hepatobiliary carcinomas.

Special Considerations in Pulmonary Embolism: Clot-in-Transit and Incidental Pulmonary Embolism

This article describes 2 relatively rare, but complex situations in pulmonary embolism (PE): clot-in-transit (CIT), incidental PE (IPE). CIT describes a venous thromboembolism that has become lodged in the right heart. CIT is associated with high mortality and presents unique challenges in management. Incidental PE (IPE) describes PE diagnosed on imaging performed for another indication. The treatment is complex because there is often a disconnect between the PE severity on imaging and lack of severity of the clinical presentation. We summarize the available literature and aid clinicians as they manage patients with PE across the clinical severity spectrum.

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.

Patient Experience of Living With Cancer-Associated Thrombosis in Canada (PELICANADA)

INTRODUCTION

Previous research from the United Kingdom and Spain has identified several areas of unmet clinical and support need for cancer patients diagnosed with venous thromboembolism. It is not known whether such experiences are restricted to those countries health care systems and culture. We therefore evaluated patients' experience of cancer-associated thrombosis (CAT) within a Canadian setting.

METHODS

Purposive sampling of patients with CAT attending a regional thrombosis clinic in Vancouver was undertaken. Semistructured interviews were audio recorded, transcribed, and coded using NVivo software. A deductive approach was taken by applying the framework matrix from the original study to these data on a case-by-case basis.

RESULTS

Twenty patients (10 male, 10 female) aged 39 to 74 (mean, 63) representing a breadth of different cancers participated. Commonalities between the UK and Canadian patients included the traumatic nature of experiencing CAT, the need for information, and adaptive behaviors through ritualization. Two new themes were identified: (1) Patients with incidental pulmonary emboli (iPE) were usually telephoned about their thrombus with little support and suboptimal communication; and (2) cost implications of accessing low-molecular-weight heparin varied according to insurance cover. Patients were sometimes converted to warfarin for financial reasons.

CONCLUSION

The distress associated with CAT is a common experience across different populations but may be ameliorated by early access to specialist services, information, and support. The current process for managing iPE could be improved with better communication and a dedicated clinical pathway. Funding issues may influence choice of anticoagulant.

Incidental pulmonary embolism in pancreatic ductal adenocarcinoma: Impact of tumor and AJCC stages at initial staging CT

BACKGROUND/OBJECTIVES

To determine the prevalence of incidental pulmonary embolism (PE) detected during initial staging CT among patients with newly diagnosed pancreatic ductal adenocarcinoma (PDAC) and assess their association with underlying tumor burden.

MATERIALS AND METHODS

This retrospective cohort study evaluated staging chest CT scans (2013-2017) to identify PE among patients with treatment naïve, biopsy-proven PDAC. Data included age, sex, T stage, AJCC stage, presence/absence of metastases and their location at diagnosis. The association of PE with tumor (T1-T4) and AJCC stage were assessed using Pearson Chi-square and Fischer's exact test. A threshold p-value of <0.05 indicated statistical significance.

RESULTS

A total of 174 patients (90 female, mean age, 68 years; range: 34-93) were identified, of which 10 patients harbored incidental PE (prevalence, 5.7%). In the PE group, two patients presented with distant metastasis (liver, 20%), while eight patients had T4 tumors (80%). No statistical association was detected between PE and age, sex, and the presence/absence or location of distant metastasis (p = 0.065, p = 0.59, p = 0.687 and p = 0.933, respectively). Patients with T4 tumors and higher AJCC stages (stage III/IV) were significantly more likely to present with PE than those with lower T stage (p = 0.045) and AJCC stage (stage I/II; p = 0.017).

CONCLUSION

The prevalence of incidental PE among PDAC patients undergoing initial CT staging is 5.7%. Patients with T4 and AJCC stages III/IV are at higher risk of PE. Caution should be exercised during radiographic interpretation of initial staging chest CTs, as incidental PE may be lurking and require treatment.

Management of Low-Risk Pulmonary Embolism

Pulmonary embolism remains a leading cause of morbidity and mortality in the United States. However, with improved recognition and diagnosis, the risk of death diminishes. The diagnosis depends on the clinician's suspicion. Pulmonary emboli are categorized into low, intermediate, or high risk based on the scoring scales and patients' hemodynamic stability versus instability. Imaging plus biomarkers help stratify patients according to risk. With the advent of the computed tomography multidetector scanners, the improved imaging has increased the detection of subsegmental and incidental pulmonary emboli. Treatment of low-risk as well as subsegmental and incidental pulmonary embolism is evolving.

Cancer-associated thrombosis: the when, how and why

Cancer-associated thrombosis (CAT) is a condition in which relevance has been increasingly recognised both for physicians that deal with venous thromboembolism (VTE) and for oncologists. It is currently estimated that the annual incidence of VTE in patients with cancer is 0.5% compared to 0.1% in the general population. Active cancer accounts for 20% of the overall incidence of VTE. Of note, VTE is the second most prevalent cause of death in cancer, second only to the progression of the disease, and cancer is the most prevalent cause of deaths in VTE patients. Nevertheless, CAT presents several peculiarities that distinguish it from other VTE, both in pathophysiology mechanisms, risk factors and especially in treatment, which need to be considered. CAT data will be reviewed in this review.

Cancer-associated thrombosis (CAT) presents peculiar features (risk factors and pathophysiology) that distinguish it from common VTE cases. Treatment of CAT requires a different approach, since the patients are more prone to recurrence and bleeding.http://ow.ly/j1Lu30nYmd5

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.

Overdiagnosis of pulmonary embolism: definition, causes and implications

Overuse of computed tomography pulmonary angiography to diagnose pulmonary embolism in people who have only a low pre-test probability of pulmonary embolism has received significant attention in the past. The issue of overdiagnosis of pulmonary embolism, a potential consequence of overtesting, has been less explored. The term “overdiagnosis”, used in a narrow sense, describes a correct (true positive) diagnosis in a person but without any associated harm. The aim of this review is to summarise literature on the topic of overdiagnosis of pulmonary embolism and translate this epidemiological concept into the clinical practice of respiratory professionals. The review concludes that the location of pulmonary embolism at a subsegmental level, rather than whether a diagnosis was made incidentally or following an investigation for suspected pulmonary embolism, is the best predictor for situations in which anticoagulation may not be necessary. In the absence of strong evidence of the optimal management of subsegmental pulmonary embolism, treatment decisions should be made case by case, taking into account the patient's situation and preference.

A suggested definition of overdiagnosis of pulmonary embolism: a diagnosis of pulmonary embolism that, if left untreated, would not lead to more harm than if it were treated with anticoagulation therapy, independent of symptomshttp://ow.ly/wgAK30nr5IV

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.

Lower prevalence of subsegmental pulmonary embolism after application of the YEARS diagnostic algorithm

The rate of identified isolated subsegmental pulmonary embolism (ssPE) has doubled with advances in computed tomography pulmonary angiography (CTPA) technology, but its clinical relevance is debated. The YEARS diagnostic algorithm was shown to safely reduce the number of required CTPAs in the diagnostic management of PE. We hypothesized that the higher threshold for performing CTPA in YEARS was associated with a lower prevalence of ssPE compared to the conventional diagnostic algorithm. We compared 2291 consecutive patients with suspected PE managed according to YEARS to 3306 consecutive control patients managed according to the Wells score for the prevalence of isolated ssPE. In the YEARS cohort, 52% were managed without CTPA, 12% had pulmonary embolism (PE) of which 10% were isolated ssPE, and the 3‐month diagnostic failure rate was 0·35%. In the control cohort, 32% were managed without CTPA, 20% had PE of which 16% were isolated ssPE, and the 3‐month failure rate was 0·73%. The isolated ssPE prevalence was significantly lower in YEARS (absolute difference 6·2% (95% confidence interval [CI] 1·4–10), Odds Ratio 0·58 (95% CI 0·37–0·90). In conclusion, YEARS is associated with a lower prevalence of isolated ssPE, due to reduction in CTPAs by the higher D‐dimer threshold. This was however not associated with a higher risk of recurrent VTE during follow‐up.

Diagnostic Yield and False-Referral Rate of Staging Chest CT in Patients with Colon Cancer

Purpose To measure the diagnostic yield and false-referral rate (FRR) of staging contrast material-enhanced chest CT based on the clinical stage from contrast-enhanced abdominal CT in patients with colon cancer. Materials and Methods This retrospective study included 1743 patients (mean age, 63.4 years; range, 18-96 years) with a diagnosis of colon cancer. The primary outcomes were diagnostic yield and FRR of contrast-enhanced chest CT in the detection of thoracic metastasis. The proportions of patients with occult thoracic metastasis and those undergoing pulmonary metastasectomy for true-positive metastases were key secondary outcomes. The outcomes were stratified according to clinical stage at contrast-enhanced abdominal CT. Results The diagnostic yields in clinical stage 0/I, cII, cIII, and cIV were 0% (95% confidence interval [CI]: 0%, 0.8%), 1.3% (95% CI: 0.4%, 3.3%), 4.4% (95% CI: 3.0%, 6.1%), and 43.3% (95% CI: 36.8%, 49.9%), respectively. The corresponding FRRs were 5.7% (95% CI: 3.8%, 8.2%), 2.9% (95% CI: 1.3%, 5.5%), 6.7% (95% CI: 5.0%, 8.8%), and 6.1% (95% CI: 3.4%, 10.0%), respectively. The proportions of patients with occult metastasis were 0% (95% CI: 0%, 0.8%), 3.3% (95% CI: 1.6%, 5.9%), 1.5% (95% CI: 0.8%, 2.7%), and 6.1% (95% CI: 3.4%, 10.0%), respectively. The proportion of patients who underwent pulmonary metastasectomy was 0% (none of 474; 95% CI: 0%, 0.8%) for clinical stage 0/I tumors. Conclusion In clinical stages 0 and I, the diagnostic yield of staging contrast-enhanced chest CT in detecting thoracic metastasis was zero. For clinical stages II, III, and IV, contrast-enhanced chest CT as a baseline examination was helpful for the detection of thoracic metastasis and allowed for the possibility of a curative metastasectomy. There was no significant association between clinical stage and false-referral rate. © RSNA, 2018 Online supplemental material is available for this article.

Symptomatic subsegmental pulmonary embolism: to treat or not to treat?

The introduction of computed tomographic pulmonary angiography and its recent increasing availability has led to a significant rise in its use to help clinicians diagnose acute pulmonary embolism (PE). This has led to a significant increase in the incidence of PE diagnoses. Simultaneously, the case fatality rate of acute PE has been decreasing and no significant change in its mortality has been noted, suggesting that the additional PE diagnoses are less severe and these patients might not benefit from anticoagulation therapy. This also seems to be correlated with an increase in the diagnosis of PE localized in the subsegmental pulmonary arteries (subsegmental pulmonary embolism [SSPE]). The clinical importance of SSPE is unclear. Whereas some studies have shown that it might be reasonable to manage patients with SSPE without anticoagulation, others have not. Although the current medical literature is limited, it suggests that a subgroup of patients with SSPE might be safely managed without the use of anticoagulant therapy. Current clinical practice guidelines suggest that clinicians take an individualized approach after carefully assessing the risk/benefit ratio for patients with SSPE and negative leg limb ultrasonography results. Prospective studies are ongoing and results are eagerly awaited to help tailor the management of this patient population.