Acute pulmonary embolism in the era of multi-detector CT: a reality in sub-Saharan Africa

Added value of hyperdense lumen sign in prediction of acute central and peripheral pulmonary embolism on non-contrast CT chest

Background

Pulmonary embolism (PE) is a common condition with considerable morbidity and mortality; it is more often diagnosed post-mortem by pathologists than in vivo by clinicians. Prompt and accurate diagnosis is difficult because PE may be clinically silent, the symptoms are vague and nonspecific, and in addition, there is no definitive, non-invasive diagnostic test to establish its diagnosis. The aim of this study is to assess the reliability of detection of acute central and peripheral pulmonary embolism (PE) on non-contrast CT especially when no possible alternative is available as in allergic cases or emergency, patients with history of renal disease, or in cases where PE is not the leading diagnosis. CT pulmonary angiography study served as our gold standard.

Results

Eighty adult patients were included in our study; 44 were females and 36 males most of which were complaining of dyspnea and chest pain. Acute central pulmonary embolism was confirmed by CTPA. They all underwent a pre-contrast study just prior to the CTPA. Presence of high attenuation emboli in any of the main pulmonary vessels was our key for diagnosis of acute embolism. Non-contrast CT chest diagnosed 26 of the 47 cases confirmed by CTPA. The hyperdense lumen sign had an overall sensitivity of 55.3%, specificity of 100%, positive predictive value (PPV) of 100%, and negative predictive value of 61.1%. The accuracy of non-contrast CT chest study was evaluated using CTPA as our gold standard.

Conclusion

Non-contrast CT chest is a good indicator in predicting central and peripheral pulmonary embolism, particularly in cases of emergency, those unable to take intravenous contrast for angiography, or in cases where pulmonary embolism is not the leading diagnosis.

A comparative analysis of the diagnostic performances of four clinical probability models for acute pulmonary embolism in a sub-Saharan African population: a cross-sectional study

Background

The diagnosis of acute pulmonary embolism (PE) is one of the most challenging in emergency settings where prompt and accurate decisions need to be taken for life-saving purposes. Here, the assessment of the clinical probability of PE is a paramount step in its diagnosis. Although clinical probability models (CPM) for PE are routinely used in emergency departments (EDs) of low-resource settings, few studies have cited their diagnostic performances in sub-Saharan Africa (SSA). We aimed to comparatively assess the accuracy of four CPM in the diagnosis of acute PE in sub-Saharan Africans.

Methods

We carried out a cross-sectional study to compare the sensitivity, specificity, positive and negative predictive values and accuracy of four CPM namely; the Wells, simplified Wells, revised Geneva and the simplified revised Geneva (SRG) Scores to computed tomography pulmonary angiography (CTPA) in all adults patients with suspected PE admitted to the EDs of the Gynaeco-obstetric and Paediatric Hospital of Yaoundé and the Yaoundé Central Hospital in Cameroon between January 1, 2017 and April 30, 2018.

Results

In total, we enrolled 30 patients with clinical suspicion of acute PE. PE was confirmed on CTPA in 16 (53.3%) cases. Their mean age was 53.7 ± 15.5 years and 36.7% were males. All four scores had a diagnostic performance superior to 50% in all criteria assessed. The simplified Wells score had the highest sensitivity (62.5%) followed by the Wells score (56.3%). The SRG score had the highest specificity (71.4%). The score with highest PPV was the SRG score (66.7%) and that with the highest NPV was the Wells score (56.3%). Overall the models with the highest accuracies were the Wells and SRG scores (60% for each).

Conclusion

All CPM had a suboptimal diagnostic performance, perhaps highlighting the need of a more optimal CPM for acute PE in SSA. However, the Wells and the SRG scores appeared to be most accurate than the other two scores in the ED. Hence, both or either of them may be used in first intention to predict PE and guide which ED patients should undergo further investigations in an emergency SSA setting.

Validity of four clinical prediction scores for pulmonary embolism in a sub-Saharan African setting: a protocol for a Cameroonian multicentre cross-sectional study

INTRODUCTION

Pulmonary embolism poses one of the most challenging diagnoses in medicine. Resolving these diagnostic difficulties is more crucial in emergency departments where fast and accurate decisions are needed for a life-saving purpose. Here, clinical pretest evaluation is an important step in the diagnostic algorithm of pulmonary embolism. Although clinical probability scores are widely used in emergency departments of sub-Saharan Africa, no study has cited their diagnostic performance in this resource-constrained environment. This study will seek to assess the performance of four routinely used clinical prediction models in Cameroonians presenting with suspicion of pulmonary embolism at the emergency department.

METHODS AND ANALYSIS

It will be a cross-sectional study comparing the sensitivity, specificity, positive and negative predictive values and accuracy of the Wells, Simplified Wells, Revised Geneva and the Simplified Revised Geneva Scores to CT pulmonary angiography as gold standard in all consecutive consenting patients aged above 15 years admitted for clinical suspicion of pulmonary embolism to the emergency departments of seven major referral hospitals of Cameroon between 1 July 2019 and 31 December 2020. The area under the receiver operating curve, calibration plots, Hosmer and Lemeshow statistics, observed/expected event rates, net benefit and decision curve will be measured of each the clinical prediction test to ascertain the clinical score with the best diagnostic performance.

ETHICS AND DISSEMINATION

Clearance has been obtained from the Institutional Review Board of the Faculty of medicine and biomedical sciences of the University of Yaounde I, Cameroon and the directorates of all participating hospitals to conduct this study. Also, informed consent will be sought from each patient or their legal next of kin and parents for minors, before enrolment into this study. The final study will be published in a peer-review journal and the findings presented to health authorities and healthcare providers.

Low-pitch peripheral systolic murmur associated with pulmonary embolism in the acute phase: a report of two cases

Acute pulmonary embolism with significant right ventricular strain could be associated with a low‐pitch peripheral systolic murmur radiating to the axillae.

Global incidence and case fatality rate of pulmonary embolism following major surgery: a protocol for a systematic review and meta-analysis of cohort studies

BACKGROUND

Pulmonary embolism (PE) is a life-threatening condition common after major surgery. Although the high incidence (0.3-30%) and mortality rate (16.9-31%) of PE in patients undergoing major surgical procedures is apparent from findings of contemporary observational studies, there is a lack of a summary and meta-analysis data on the epidemiology of postoperative PE in this same regard. Hence, we propose to conduct the first systematic review to summarise existing data on the global incidence, determinants and case fatality rate of PE following major surgery.

METHODS

Electronic databases including MEDLINE, EMBASE, SCOPUS, WHO global health library (including LILACS), Web of Science and Google scholar from inception to April 30, 2017, will be searched for cohort studies reporting on the incidence, determinants and case fatality rate of PE occurring after major surgery. Data from grey literature will also be assessed. Two investigators will independently perform study selection and data extraction. Included studies will be evaluated for risk of bias. Appropriate meta-analytic methods will be used to pool incidence and case fatality rate estimates from studies with identical features, globally and by subgroups of major surgical procedures. Random-effects and risk ratio with 95% confidence interval will be used to summarise determinants and predictors of mortality of PE in patients undergoing major surgery.

DISCUSSION

This systematic review and meta-analysis will provide the most up-to-date epidemiology of PE in patients undergoing major surgery to inform health authorities and identify further research topics based on the remaining knowledge gaps.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42017065126.

The prevalence and radiological findings of pulmonary embolism in HIV-positive patients referred for computed tomography pulmonary angiography in the Western Cape of South Africa

Aim:

To provide imaging data and report associations between human immunodeficiency virus (HIV), tuberculosis (TB) and pulmonary embolism (PE) in a South African population that underwent computed tomography pulmonary angiography (CTPA) for suspected PE.

Methods:

A validated Qanadli severity scoring system for PE was used for 164 CTPA scans, and parenchymal, pleural and cardiovascular complications were reported. Serological confirmation of HIV testing and microbiological confirmation of TB were recorded.

Results:

Prevalence of PE in the CTPA population was 26% (95% CI: 19.67–33.65%). HIV-positive prevalence in patients with PE was 67% (95% CI: 48.17–82.04%), however it was not statistically significantly different when compared with the patients without PE (p = 1). HIV-positive patients had more extensive partial thrombus in the right middle lobe (p = 0.045), but no other differences when compared with HIV-negative patients. TB prevalence in patients with PE was 57% (95% CI: 34.49–76.81%). This was statistically significantly different when compared with the patients without PE (p = 0.073 at the 10% level). Prevalence of TB co-morbidity in the HIV-positive group with proven PE was 71% (95% CI: 41.90– 91.61%), however there was no statistically significant difference in comparison with the HIV-negative patients with TB and PE (p= 0.305).

Conclusion:

The high number of patients presenting for CTPA who were HIV infected (and also infected with TB) highlights that PE evaluation should include severity/extent of the disease, as these patients may have more severe disease in specific lung lobes. The use of a validated scoring system, such as the Qanadli score, when reporting PE may have a profound effect on patient risk stratification, management and prognosis and would also provide a system for collecting larger volumes of data for analysis.