Combining lung ultrasound and Wells score for diagnosing pulmonary embolism in critically ill COVID-19 patients

Abstract

Subpleural consolidations have been found in lung ultrasound in patients with COVID-19, possibly deriving from pulmonary embolism (PE). The diagnostic utility of impact of lung ultrasound in critical-ill patients with COVID-19 for PE diagnostics however is unclear. We retrospectively evaluated all SARS-CoV2-associated ARDS patients admitted to our ICU between March 8th and May 31th 2020. They were enrolled in this study, when a lung ultrasound and a computed tomography pulmonary angiography (CTPA) were documented. In addition, wells score was calculated to estimate the probability of PE. The CTPA was used as the gold standard for the detection of PE. Twenty out of 25 patients met the inclusion criteria. In 12/20 patients (60%) (sub-) segmental PE were detected by CT-angiography. Lung ultrasound found subpleural consolidations in 90% of patients. PE-typical large supleural consolidations with a size ≥ 1 cm were detectable in 65% of patients and were significant more frequent in patients with PE compared to those without (p = 0.035). Large consolidations predicted PE with a sensitivity of 77% and a specificity of 71%. The Wells score was significantly higher in patients with PE compared to those without (2.7 ± 0.8 and 1.7 ± 0.5, respectively, p = 0.042) and predicted PE with an AUC of 0.81. When combining the two modalities, comparing patients with considered/probable PE using LUS plus a Wells score ≥ 2 to patients with possible/unlikely PE in LUS plus a Wells score < 2, PE could be predicted with a sensitivity of 100% and a specificity of 80%. Large consolidations detected in lung ultrasound were found frequently in COVID-19 ARDS patients with pulmonary embolism. In combination with a Wells score > 2, this might indicate a high-risk for PE in COVID-19.

COVID-19 and venous thromboembolism: Known and unknown for imaging decisions

“…Studies on the use of clinical probability scoring in COVID-19 patients is thus far very limited. One study indicated a Wells score > 2 had a higher correlation for VTE on imaging in critically ill COVID-19 patients[ 18 ]. Despite the limited evidence, use of a clinical prediction scoring tool should be considered in conjunction with clinical judgement when defining pretest probability of VTE in COVID-19 patients.…”

A Pictorial Review of the Role of Imaging in the Detection, Management, Histopathological Correlations, and Complications of COVID-19 Pneumonia

“…Although LUS is not currently considered in the main international guidelines for COVID-19 patient management, some authors have proposed semi-quantitative LUS scores for COVID-19 pneumonia, which can be used to quantify lung aeration [ 55 , 61 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 ]. The most widely used is called the lung ultrasound score (LUSS) [ 61 ], global or total LUS score [ 89 , 91 ], or global LUS aeration score [ 93 ], in which 0–3 points are assigned for each of the 12 zones according to ultrasound features [ 84 , 85 , 86 , 87 , 89 , 90 ]: 0 = normal; 1 = well-defined B lines (B1); 2 = coalescent B lines or white lung (B2); and 3 = consolidation ( Figure 5 ).…”

“…Peschel et al [ 93 ] used 0 to 4 points for up to 12 zones; this score, called the lung aeration score (LAS), is assessed by calculating the arithmetic mean of the points of all examined areas. Recently, Zotzmann et al [ 92 ] advocated a combination of LUS and the Wells score as a screening tool for pulmonary embolism (PE) in COVID-19 ARDS. The baseline LUS score (within 24 h of admission) would be roughly linked to the eventual need for invasive mechanical ventilation and would be a strong predictor of mortality [ 91 ].…”

Cardiovascular Imaging Evaluation in COVID-19 Heart and Vascular Non-Ischaemic Involvement

“…It has been explained how pulmonary thrombosis and arterial and venous thromboembolism affecting a sizeable proportion of patients in ICU, could cause DVT, PE, ischaemic stroke, myocardial infarction and systemic arterial embolism [153]. Zotzmann et al [154] retrospectively evaluated all SARS-CoV2-associated ARDS patients admitted to ICU who underwent lung ultrasound and a computed tomography pulmonary angiography (CTPA) that was considered the gold standard for the detection of PE. In addition, Wells score was calculated to estimate the probability of PE.…”

“…In combination with a Wells score >2, this may indicate a high-risk for PE in COVID-19. [154] Accumulating evidence suggests that despite the use of anticoagulant therapy, there is a high incidence of thromboembolism events leading to the hyperinflammatory state especially in ICU patients [131]. Worth noticing, the majority of patients admitted to the ICU who requires infusion of vasoactive agents or haemodialysis receives a central venous catheter (CVC) that often produces catheter-related thrombosis (CRT).…”