|Year : 2020 | Volume
| Issue : 2 | Page : 27-28
Nformbuh Asangmbeng, Anekwe Onwuanyi
Department of Medicine, Morehouse School of Medicine, Atlanta, Georgia, USA
|Date of Submission||04-Dec-2021|
|Date of Acceptance||07-Dec-2021|
|Date of Web Publication||29-Jan-2022|
Prof. Anekwe Onwuanyi
Department of Medicine, Morehouse School of Medicine, Atlanta, Georgia
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Asangmbeng N, Onwuanyi A. Guest editorial. Niger J Cardiovasc Thorac Surg 2020;5:27-8
The article by Nwiloh et al. published in this edition of the Nigerian Journal of Cardiovascular and Thoracic Surgery examines the current management of venous thromboembolism (VTE) in sub-Saharan Africa. Pulmonary embolism (PE) is a major cause of cardiovascular mortality, and its incidence is believed to be underestimated due to overlapping clinical presentation with other conditions such as myocardial infarction and sudden death. The annual incidence of VTE exceeds 1/1000; over 200,000 new cases occur in the United States. The incidence reported by the authors in this selected population should be noted only as such without further extrapolations or conflating with autopsy series. However, one point to be made is that the presence of risk factors for PE has increased with more long-distance air travel.
There are several diagnostic tools available to aid diagnosis and risk stratification of patients with presumed PE including a variety of clinical risk scores such as Wells, biomarkers such as D-dimer, troponin, brain natriuretic peptide, and imaging modalities such as compression ultrasonography, transthoracic echocardiography, ventilation–perfusion scan, and computed tomography angiography (CTA). The utility of the biomarkers is their appropriate integration and interpretation in the right clinical context. Since resources are limited, it will be appropriate to limit use to one or two of them. D-dimer levels are sensitive but not necessarily specific to PE because elevated D-dimer is also present in various disorders including infections, malignancy, and inflammation. Therefore, D-dimer has a low positive predictable value but a remarkably high negative predictable value. This makes D-dimer a particularly good screening test for PE, especially in low to intermediate pretest probabilities. Wells' criteria, in combination with D-dimer, will be particularly useful in an under-resourced practice environment because of the discriminative impact on the exclusion of the low-risk patient.
Due to limited access to CTA in some areas in Africa, echocardiography has emerged as a major diagnostic and management tool for suspected PE patients. One of the challenges is the appropriate deployment. Echocardiography is an important test both for diagnostic and management decisions in the sicker patient. It is necessary for the hemodynamically unstable patient and often provides important information for adequate triage and treatment of the patient. However, the high incidence (57.1%) of the right ventricular (RV) thrombus in patients with PE reported by the authors of this paper is unusually high. Other echocardiographic findings supportive of PE include RV dysfunction and signs of RV pressure overload such as 60/60 sign, McConnell's sign (RV free wall akinesis sparing the apex), signs of the right heart overload/failure include increased RV/LV dimension ratio, dilation of RV (up to 5 mm), paradoxical ventricular septal motion, D-shape of the interventricular septum, RV dilation, pulmonary artery dilation, regurgitation flow on the tricuspid valve >2.8 m/s = gradient 31 mmHg, and reduced inferior vena cava fluctuations with respiration (<40%). The benefit of echocardiography is less well defined when differentiating the intermediate low-risk patients from the small PE low-risk patients. As a result, the American Society of Echocardiography has additional guidelines to better delineate RV function to help in this regard. These additional echocardiographic parameters may include (tricuspid/mitral annular plane systolic excursions) assessed using M-mode, fractional change in RV area, tissue Doppler echocardiography-documented tricuspid annular plane systolic excursion, longitudinal strain and strain rate, RV index of myocardial performance, and two-dimensional fractional area change.
The authors highlight the management challenges of VTE in an under-resourced practice environment. However, the focus of the study is on a premortem population. While understanding the import of their observation, what is most required now is the effective application and optimization of the current clinical knowledge in delivering care to this population. Perhaps, the provision of handheld ultrasound devices (limited technology application) may be useful in this environment. A few studies have been conducted to evaluate the sensitivity and specificity of handheld ultrasound devices. One of these studies showed although handheld devices remain inferior to standard transthoracic echocardiography, handheld devices are cheaper, more accessible, and portable. In addition, the devices can increase the diagnostic accuracy over the standard physical examination. Another study showed more than 90% diagnostic correlation between handheld devices and standard transthoracic echocardiography. These handheld devices are some of the more affordable and accessible medical technologies which can help medical professionals where resources are limited like in sub-Saharan Africa for the diagnosis of potential deadly diseases including VTE.
| References|| |
Nwiloh J, Orumwense N, Okoye I, Nwagbara C, Ajaegbu OC, Ozuemba BC. Acute venous thromboembolism in a limited resource healthcare system: Mitigating management challenges. Niger J Cardiovasc Thorac Surg 2020;In Press.
Heit JA, Silverstein MD, Mohr DN, Petterson TM, Lohse CM, O'Fallon WM, et al.
The epidemiology of venous thromboembolism in the community. Thromb Haemost 2001;86:452-63.
Stein PD, Hull RD, Patel KC, Olson RE, Ghali WA, Brant R, et al.
D-dimer for the exclusion of acute venous thrombosis and pulmonary embolism: A systematic review. Ann Intern Med 2004;140:589-602.
Kreit JW. The impact of right ventricular dysfunction on the prognosis and therapy of normotensive patients with pulmonary embolism. Chest 2004;125:1539-45.
Rudski LG, Lai WW, Afilalo J, Hua L, Handschumacher MD, Chandrasekaran K, et al.
Guidelines for the echocardiographic assessment of the right heart in adults: A report from the American Society of Echocardiography endorsed by the European Association of Echocardiography, a registered branch of the European Society of Cardiology, and the Canadian Society of Echocardiography. J Am Soc Echocardiogr 2010;23:685-713.
Mehta M, Jacobson T, Peters D, Le E, Chadderdon S, Allen AJ, et al.
Handheld ultrasound versus physical examination in patients referred for transthoracic echocardiography for a suspected cardiac condition. JACC Cardiovasc Imaging 2014;7:983-90.
Kitada R, Fukuda S, Watanabe H, Oe H, Abe Y, Yoshiyama M, et al.
Diagnostic accuracy and cost-effectiveness of a pocket-sized transthoracic echocardiographic imaging device. Clin Cardiol 2013;36:603-10.