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

Abstract

Background Improved imaging techniques have increased the incidence of subsegmental pulmonary embolism (ssPE). Indirect evidence is suggesting that ssPE may represent a more benign presentation of venous thromboembolism not necessarily requiring anticoagulant treatment. However, correctly diagnosing ssPE is challenging with reported low interobserver agreement, partly due to the lack of widely accepted diagnostic criteria. Objectives We sought to derive uniform diagnostic criteria for ssPE, guided by expert consensus. Methods Based on an extensive literature review and expert opinion of a Delphi steering committee, two surveys including statements regarding diagnostic criteria and management options for ssPE were established. These surveys were conducted electronically among two panels, respectively: expert thoracic radiologists and clinical venous thromboembolism specialists. The Delphi method was used to achieve consensus after multiple survey rounds. Consensus was defined as a level of agreement >70%. Results Twenty‐nine of 40 invited radiologists (73%) and 40 of 51 clinicians (78%) participated. Following two survey rounds by the expert radiologists, consensus was achieved on 15 of 16 statements, including on the established diagnostic criteria for ssPE (96% agreement): a contrast defect in a subsegmental artery, that is, the first arterial branch division of any segmental artery independent of artery diameter, visible in at least two subsequent axial slices, using a computed tomography scanner with a desired maximum collimator width of ≤1 mm. These criteria were approved by 83% of the clinical venous thromboembolism (VTE) specialists. The clinical expert panel favored anticoagulant treatment in case of prior VTE, antiphospholipid syndrome, pregnancy, cancer, and proximal deep vein thrombosis. Conclusion The results of this analysis provide standard radiological criteria for ssPE that may be applicable in both clinical trials and practice.

Incidence of thrombotic complications and overall survival in hospitalized patients with COVID-19 in the second and first wave

“…very small clots of uncertain relevance [ 23 ]. An alternative, technical explanation for this increase could be that the CTPA image quality was better in the second wave, with better visualization of subsegmental arteries, because more patients were diagnosed while they were admitted in the ward and not intubated, allowing for scanning during breath-hold [ 24 ]. On the other hand, detection and treatment of PEs, even small ones, may also have contributed to the better overall prognosis in the second wave, which is an argument against overdiagnosis.…”

Epidemiology and prevention of venous thromboembolism

“…Owing to the lack of surveillance for VTE at the population level, estimates of VTE incidence rely on incomplete data and on assumptions to complete the picture. Interpretation of most sources of data on VTE incidence should be viewed in light of secular trends and data characteristics that lead to higher 29 , 30 or lower 31 – 33 estimates of VTE incidence (Box 1 ). There is a clear need for population-based VTE surveillance, particularly in the developing world and in populations at risk of VTE.…”

“…Higher estimates Advances in imaging of pulmonary embolism, which lead to the detection of smaller pulmonary embolisms 29 and poor interobserver agreement on the diagnosis of small pulmonary embolisms 30 Increased use of full-leg ultrasonography, which detects distal deep-vein thrombosis Co-occurrence of deep-vein thrombosis and pulmonary embolism in the same patient (might be double-counted in some data sources) …”

ERS International Congress 2021: highlights from the Pulmonary Vascular Diseases Assembly

“…According to Behnood Bikdeli the therapeutic approach to subsegmental PE (SSPE) remains controversial, because of the non-uniform definition and the overdiagnosis of this condition [ 27 ]. Based on the Delphi analysis of experts, SSPE is defined as a contrast defect in a subsegmental artery visible in at least two subsequent axial slices of 1 mm or less [ 28 ]. With the aim of reducing overdiagnosis in the interpretation of CTPA, it is necessary to pay attention to the quality of the image and possible artefacts, as well as the analysis of lung parenchyma and airways, in order to exclude false positive findings [ 29 ].…”

“…Mortality associated with SSPE is low, but the risk of recurrence is not lower compared to patients with central PE. Initiation of anticoagulant therapy is recommended if SSPE occurs in patients with a previous thromboembolic event, antiphospholipid syndrome, pregnancy, cancer or proximal DVT [ 28 ].…”