Ruling out Pulmonary Embolism in Patients with High Pretest Probability

Abstract

IntroductionThe American College of Emergency Physicians guidelines recommend more aggressive workup beyond imaging alone in patients with a high pretest probability (PTP) of pulmonary embolism (PE). However, the ability of multiple tests to safely rule out PE in high PTP patients is not known. We sought to measure the ability of negative computed tomography pulmonary angiography (CTPA) along with negative D-dimer to rule out PE in these high-risk patients.MethodsWe analyzed data from a previous prospective observational study conducted in 12 emergency departments (ED). Wells score criteria were entered by providers before final PE testing. PE was diagnosed by imaging on the index ED visit, or within 45 days, demonstrating either PE or deep vein thrombosis (DVT), or if the patient died of PE during the 45-day, follow-up period. Testing threshold was set at 1.8%.ResultsA total of 7,940 patients were enrolled and tested for PE, and 257 had high PTP (Wells >6). Sixteen of these high-risk patients had negative CTPA and negative D-dimer, of whom two were positive for PE (12.5% [95% confidence interval {2.2%–40.0%}]). One of these patients had a DVT on CT venogram and the other was diagnosed at follow-up.ConclusionOur analysis suggests that in patients with high PTP of PE, neither negative CTPA by itself nor a negative CTPA plus a negative D-dimer are sufficient to rule out PE. More aggressive workup strategies may be required for these patients.

A 60-Year-Old Woman with a 6-Week History of Shortness of Breath and Intermittent Chest Pain Due to Chronic Thromboembolic Pulmonary Disease Undetected by Computed Tomography Pulmonary Angiography (CTPA) and Diagnosed by Ventilation-Perfusion Imaging

“…The presence of false-negative CTPA studies in patients with established pulmonary embolic disease observed by Moores et al [ 8 ] has been reaffirmed by several retrospective studies and systematic reviews [ 10 – 12 ]. In a cohort of 201 patients deemed to be at high risk for CTEPD (Wells score ≥6), Akhter et al [ 10 ] identified 16 patients with evident PE despite a negative CTPA study.…”

“…The presence of false-negative CTPA studies in patients with established pulmonary embolic disease observed by Moores et al [ 8 ] has been reaffirmed by several retrospective studies and systematic reviews [ 10 – 12 ]. In a cohort of 201 patients deemed to be at high risk for CTEPD (Wells score ≥6), Akhter et al [ 10 ] identified 16 patients with evident PE despite a negative CTPA study. Systematic reviews conducted by Hogg et al [ 11 ] and Kligerman et al [ 12 ] have demonstrated that false-negative CTPA studies is a ubiquitous issue in the investigation and diagnosis of CTEPD.…”

“…The higher detection rates for CTEPD with V/Q imaging may be attributed to an enhanced depiction of sub-segmental PEs, compared with CTPA [ 10 ]. This is because V/Q scintigraphy is known to provide improved contrast and better 3D representation of the pulmonary vascular tree without overlapping structures, leading to a greater overall sensitivity.…”

Prognostic Value of D-Dimer in Younger Patients with Pulmonary Embolism

“…Pulmonary embolism (PE) is a common life-threatening condition which contributes to the global burden of cardiovascular diseases in terms of morbidity and mortality (1)(2)(3)(4)(5). The 30-day mortality rate due to PE exceeds 15% (6).…”

Importance of computed tomography pulmonary angiography for predict 30-day mortality in acute pulmonary embolism patients

“…Nevertheless, the operator-dependent and technical challenges of imaging the right heart have limited this modality [ 7 ]. As the frontier imaging modality for APE diagnosis [ [8] , [9] , [10] , [11] ], computed tomography pulmonary angiography (CTPA) has increasingly been established. CTPA provides the advantage of a more comprehensive assessment of the severity of obstruction of the pulmonary artery compared with echocardiography, which can simultaneously diagnose RVD, related underlying pulmonary disease, and other causes of acute chest pain [ 12 , 13 ].…”