Incidence and morphological characteristics of the reversed halo sign in patients with acute pulmonary embolism and pulmonary infarction undergoing computed tomography angiography of the pulmonary arteries.

OBJECTIVE: To determine the incidence of the reversed halo sign (RHS) in patients with pulmonary infarction (PI) due to acute pulmonary embolism (PE), detected by computed tomography angiography (CTA) of the pulmonary arteries, and to describe the main morphological features of the RHS. METHODS: We evaluated 993 CTA scans, stratified by the risk of PE, performed between January of 2010 and December of 2014. Although PE was detected in 164 scans (16.5%), three of those scans were excluded because of respiratory motion artifacts. Of the remaining 161 scans, 75 (46.6%) showed lesions consistent with PI, totaling 86 lesions. Among those lesions, the RHS was seen in 33 (38.4%, in 29 patients). RESULTS: Among the 29 patients with scans showing lesions characteristic of PI with the RHS, 25 (86.2%) had a single lesion and 4 (13.8%) had two, totaling 33 lesions. In all cases, the RHS was in a subpleural location. To standardize the analysis, all images were interpreted in the axial plane. Among those 33 lesions, the RHS was in the right lower lobe in 17 (51.5%), in the left lower lobe in 10 (30.3%), in the lingula in 5 (15.2%), and in the right upper lobe in 1 (3.0%). Among those same 33 lesions, areas of low attenuation were seen in 29 (87.9%). The RHS was oval in 24 (72.7%) of the cases and round in 9 (27.3%). Pleural effusion was seen in 21 (72.4%) of the 29 patients with PI and the RHS. CONCLUSIONS: A diagnosis of PE should be considered when there are findings such as those described here, even in patients with nonspecific clinical symptoms.

Incidence and morphological characteristics of the reversed halo sign in patients with acute pulmonary embolism and pulmonary infarction undergoing computed tomography angiography of the pulmonary arteries / Incidência e características morfológicas do sinal do halo invertido em pacientes com tromboembolismo pulmonar agudo e infarto pulmonar submetidos a angiotomografia de artérias pulmonares

ABSTRACT Objective: To determine the incidence of the reversed halo sign (RHS) in patients with pulmonary infarction (PI) due to acute pulmonary embolism (PE), detected by computed tomography angiography (CTA) of the pulmonary arteries, and to describe the main morphological features of the RHS. Methods: We evaluated 993 CTA scans, stratified by the risk of PE, performed between January of 2010 and December of 2014. Although PE was detected in 164 scans (16.5%), three of those scans were excluded because of respiratory motion artifacts. Of the remaining 161 scans, 75 (46.6%) showed lesions consistent with PI, totaling 86 lesions. Among those lesions, the RHS was seen in 33 (38.4%, in 29 patients). Results: Among the 29 patients with scans showing lesions characteristic of PI with the RHS, 25 (86.2%) had a single lesion and 4 (13.8%) had two, totaling 33 lesions. In all cases, the RHS was in a subpleural location. To standardize the analysis, all images were interpreted in the axial plane. Among those 33 lesions, the RHS was in the right lower lobe in 17 (51.5%), in the left lower lobe in 10 (30.3%), in the lingula in 5 (15.2%), and in the right upper lobe in 1 (3.0%). Among those same 33 lesions, areas of low attenuation were seen in 29 (87.9%). The RHS was oval in 24 (72.7%) of the cases and round in 9 (27.3%). Pleural effusion was seen in 21 (72.4%) of the 29 patients with PI and the RHS. Conclusions: A diagnosis of PE should be considered when there are findings such as those described here, even in patients with nonspecific clinical symptoms.

RESUMO Objetivo: Verificar a incidência do sinal do halo invertido (SHI) associado a infartos pulmonares (IP) relacionados ao tromboembolismo pulmonar (TEP) agudo, identificado por angiotomografia (angio-TC) de artérias pulmonares, e demonstrar as principais características morfológicas do SHI. Métodos: Foram avaliadas 993 angio-TCs, após estratificação de risco clínico para TEP entre janeiro de 2010 e dezembro de 2014. TEP foi encontrado em 164 pacientes (16,5%), sendo que três exames foram descartados devido a artefatos de movimentação respiratória. Dos 161 exames restantes, em 75 (46,6%) foram identificadas imagens compatíveis com IP, totalizando 86 lesões; o SHI foi observado em 33 (38,4% dos pacientes) dessas lesões. Resultados: Dos 29 pacientes com lesões características de IP com o SHI, 25 pacientes (86,2%) apresentavam lesão única e 4 (13,8%), lesão dupla. Todas as imagens compatíveis com SHI eram de localização subpleural. Para padronizar a análise, todas as imagens foram interpretadas no plano axial. Em relação à distribuição lobar das 33 lesões, o SHI estava localizado no lobo inferior direito, em 17 (51,5%); no lobo inferior esquerdo, em 10 (30,3%); na língula, em 5 (15,2%) e no lobo superior direito, em 1 (3,0%). Áreas de baixa atenuação no interior dos IPs com o SHI foram observadas em 29 das 33 lesões (87,9%). O SHI apresentava formato ovalado em 24 (72,7%) dos casos e formato arredondado, em 9 (27,3%). Derrame pleural foi encontrado associado aos IP com o SHI em 21 pacientes (72,4%). Conclusões: O achado de imagens com essas características, mesmo em pacientes com sintomatologia inespecífica, deve alertar para a possibilidade do diagnóstico de TEP.

Association of Vegetation Size With Embolic Risk in Patients With Infective Endocarditis: A Systematic Review and Meta-analysis.

Importance: Infective endocarditis is a life-threating condition with annual mortality of as much as 40% and is associated with embolic events in as many as 80% of cases. These embolic events have notable prognostic implications and have been linked to increased length of stay in intensive care units and mortality. A vegetation size greater than 10 mm has often been suggested as an optimal cutoff to estimate the risk of embolism, but the evidence is based largely on small observational studies. Objective: To study the association of vegetation size greater than 10 mm with embolic events using meta-analytic techniques. Data Sources: A computerized literature search of all publications in the PubMed and EMBASE databases from inception to May 1, 2017, was performed with search terms including varying combinations of infective endocarditis, emboli, vegetation size, pulmonary infarct, stroke, splenic emboli, renal emboli, retinal emboli, and mesenteric emboli. This search was last assessed as being up to date on May 1, 2017. Study Selection: Observational studies or randomized clinical trials that evaluated the association of vegetation size greater than 10 mm with embolic events in adult patients with infective endocarditis were included. Conference abstracts and non-English language literature were excluded. The search was conducted by 2 independent reviewers blinded to the other's work. Data Extraction and Synthesis: Following PRISMA guidelines, the 2 reviewers independently extracted data; disputes were resolved with consensus or by a third investigator. Categorical dichotomous data were summarized across treatment arms using Mantel-Haenszel odds ratios (ORs) with 95% CIs. Heterogeneity of effects was evaluated using the Higgins I2 statistic. Results: The search yielded 21 unique studies published from 1983 to 2016 with a total of 6646 unique patients with infective endocarditis and 5116 vegetations with available dimensions. Patients with a vegetation size greater than 10 mm had increased odds of embolic events (OR, 2.28; 95% CI, 1.71-3.05; P < .001) and mortality (OR, 1.63; 95% CI, 1.13-2.35; P = .009) compared with those with a vegetation size less than 10 mm. Conclusions and Relevance: In this meta-analysis of 21 studies, patients with vegetation size greater than 10 mm had significantly increased odds of embolism and mortality. Understanding the risk of embolization will allow clinicians to adequately risk stratify patients and will also help facilitate discussions regarding surgery in patients with a vegetation size greater than 10 mm.

Allergy and Venous Thromboembolism: A Casual or Causative Association.

Allergic diseases are very frequent conditions worldwide. The pathogenesis of allergic reactions and venous thromboembolism (VTE) shares several risk factors and predisposing conditions. In particular, the concentration of immunoglobulin E (IgE) is considerably increased in patients with allergic diseases, and this immunoglobulin exert many prothrombotic and antifibrinolytic activities, especially through interaction with mast cells. Therefore, this narrative review is aimed to provide an overview of the current scientific evidence supporting a potential relationship between allergy and the risk of VTE. Although no prospective studies have been published so far, the evidence provided by six large cross-sectional studies and several case reports support the existence of an unquestionable epidemiological association between different allergic diseases (especially atopy, asthma, and celiac disease) and venous thrombosis. Two additional investigations reported that the concentration of IgE might predict the onset of severe complications of pulmonary embolism such as pulmonary infarction and pleural fluid accumulation. Therefore, the existence of a convincing epidemiologic link between allergy and VTE paves the way to future investigations aimed to establish whether the prevention or treatment of allergic diseases might be regarded as an effective measure to lower the risk of VTE.

Predictors of Pulmonary Infarction.

In the setting of acute pulmonary embolism (PE), pulmonary infarction is deemed to occur primarily in individuals with compromised cardiac function.The current study was undertaken to establish the prevalence of pulmonary infarction in patients with acute PE, and the relationship between infarction and: age, body height, body mass index (BMI), smoking habits, clot burden, and comorbidities.The authors studied prospectively 335 patients with acute PE diagnosed by computed tomographic angiography (CT) in 18 hospitals throughout central Italy. The diagnosis of pulmonary infarction on CT was based on Hampton and Castleman's criteria (cushion-like or hemispherical consolidation lying along the visceral pleura). Multivariable logistic regression was used to model the relationship between covariates and the probability of pulmonary infarction.The prevalence of pulmonary infarction was 31%. Patients with infarction were significantly younger and with significantly lower prevalence of cardiovascular disease than those without (P < 0.001). The frequency of infarction increased linearly with increasing height, and decreased with increasing BMI. In logistic regression, the covariates significantly associated with the probability of infarction were age, body height, BMI, and current smoking. The risk of infarction grew with age, peaked at approximately age 40, and decreased afterwards. Increasing body height and current smoking were significant amplifiers of the risk of infarction, whereas increasing BMI appeared to confer some protection.Our data indicate that pulmonary infarction occurs in nearly one-third of the patients with acute PE. Those with infarction are often young and otherwise healthy. Increasing body height and active smoking are predisposing risk factors.