key: cord-1018700-d6n3eotq
authors: van Twist, Daan J. L.; Luu, Inge H. Y.; Kroon, Féline P. B.; Mostard, Rémy L. M.; Buijs, Jacqueline
title: Pulmonary Embolism in COVID-19: The Actual Prevalence Remains Unclear
date: 2021-03-16
journal: Radiology
DOI: 10.1148/radiol.2021204671
sha: 2a15ef952fcfccdfaa68874966e764bce851b755
doc_id: 1018700
cord_uid: d6n3eotq

nan

We appreciate your interest and valuable comments on our work (1) and agree that our results need to be cautiously interpreted. The actual incidence of PE in patients with COVID-19 would ideally be determined on the basis of the uniform application of diagnostic testing (ie, CT pulmonary angiography) with a predefined systematic indication for testing. Other factors affecting testing, including patient location (ie, general ward vs intensive care unit) and prophylactic anticoagulation, should also be controlled by analyzing a sufficiently large study population. However, assessing the actual incidence under such settings is often impractical, particularly for early observation studies. Although we provided a single summary estimate for readers to capture average incidence straightforwardly, we showed the distribution of PE incidence in a large study population by collecting all relevant publications and proposed that the actual incidence of PE in patients with COVID-19 may be within a range between 11.3% (in populations with a proportion of CT pulmonary angiography testing that is < 100% or unknown) and 30.2% (in populations where CT pulmonary angiography is performed in 100% of cases). We also examined the degree to which PE incidence varied according to study-level characteristics by meta-regression and forest plotting.

The negative predictive value of d-dimer testing is high, and a normal d-dimer level renders acute PE or venous This copy is for personal use only. To order printed copies, contact reprints@rsna.org thromboembolism unlikely. The current guidelines recommend or suggest measuring d-dimer levels as the first-line test to exclude PE in populations with a low or intermediate pretest probability of PE, with a negative d-dimer test ruling out PE, and no additional testing is required (2, 3) . Therefore, the comment on excluding patients with low d-dimer levels from the analysis does not seem to be practical.

We believe that our analysis will help readers estimate the incidence of PE in patients with COVID-19 in their practice setting and suggest that well-designed prospective studies will fill the gap between our analysis and the actual incidence of PE with an optimal d-dimer cutoff (including age-specific cutoffs). 

Pulmonary Embolism and Deep Vein Thrombosis in COVID-19: A Systematic Review and Meta-Analysis

The Task Force for the diagnosis and management of acute pulmonary embolism of the European Society of Cardiology (ESC)

American Society of Hematology 2018 guidelines for management of venous thromboembolism: diagnosis of venous thromboembolism