Acute Pulmonary Embolism: A Summary and Evaluation
The pulmonary embolism—blockage of pulmonary arteries form blood clots (emboli) that usually originates within the veins of the legs (or deep vein thrombosis) and are usually symptomless yet deadly. In acute pulmonary embolism, the obstruction of the arteries is undoubtedly the most important cause of compromised physiology, in which patients often have chest pain, either sudden in onset or evolving over a period of days and weeks.
Venous thromboembolism, or the formation and split up of blood clots in venous valves, is a worldwide problem, particularly in people with known risk factors. In the US alone, as many as 300,000 people die from acute pulmonary embolism, while it is less common in Asian region. About 79% of patients who present pulmonary embolism have evidence of deep venous thrombosis in their legs and conversely, pulmonary embolism occurs in up to 50% of patients with proximal deep venous thrombosis in their legs (Tapson, 2008, 1037).
Risk for pulmonary embolism may range from acquired factors and those inherent genetic predispositions. Patients who have had total hip and knee surgery and surgery for cancer are at high risk, as do patients who had trauma and spinal cord injury. While hospitalized patients are particularly at high risk, some symptoms do not appear until after their discharge. Reduced mobility and sedentary lifestyle, notably occupations involving sitting for long periods of time, also confers increased risk, though the extent of development of the disease remains unclear. Persons who are subjected to extended air or ground travel also have an increase risk of thromboembolism. Aging, notably persons over the age of 40 years is considered a risk factor. Pregnant women or those in after birth (postpartum) period and women receiving hormonal therapy are all at risk for venous thromboembolism.
Genetic conditions, such as deficiencies in protein C, protein S, and antithrombin substantially increase the risk of thrombosis and thromboembolic events. Factor V Leiden, which causes activated protein C resistance, is the most common genetic risk factor for thrombophilia (Tapson, 2008, p. 1039). In patients with conditions such as cancer and the thrompophilias, acquired risk and genetic predisposition may overlap.
Diagnosing a patient can be done through clinical test; enzyme-linked immunosorbent assay (ELISA)-based d-dimer tests are found to be effective tool in diagnosis (96% to 98% correct) of the disease (Tapson, 2008, p. 1040). The test result is best considered together with clinical probability and is helpful in assessing the likelihood that a patient has acute pulmonary embolism. Also, electrocardiogram abnormalities, including unexplained tachycardia, are common in pulmonary embolism but are not definitvive characteristic.
Aside from clinical tests, medical imaging has been used in diagnosing acute pulmonary embolism, those include, magnetic resonance imaging (MRI), contrast-enhanced computed tomographic (CT) arteriography, ventilation-perfusion scanning, and standard pulmonary arteriography. CT arteriography has the greatest sensitivity and specificity for detecting emboli in the main, lobar, or segmented arteries (Tapson, 2008, p. 1041).
Treatment of patients diagnosed can be done through anticoagulation procedure; using blood thinners (like low-molecular-weight heparin) as the anticoagulant agent. The adequate use of blood thinners for patients with acute pulmonary embolism have been proven effective in treating the disease in various clinical settings.
Use of an optional inferior vena caval filter (IVCF) also offers the potential for removal of clots when risk factors are believed to be temporarily. The use of filter replacement may be considered in patient with massive spread of blood clots and prevent its spread but this indication has not been studied in prospective, randomized clinical trials.
While the mortality rate for untreated pulmonary embolism is relatively high, immediate diagnosis and treatment of the disease have been shown to reduce the risk of death. Prompt testing for patients suspected to have pulmonary embolism is deemed important step and assessment of risk factors and clinical probability goes together in the process. Also, preventive measures were also important for patients that have high risk of developing the disease, such as patients who have undergone surgery of the hip and knee, and also those that have trauma and spinal cord injury.
The article, entitled “Acute Pulmonary Embolism” by V. F. Tapson, M.D. discussed a thorough medical review of the disease. A detailed discussion of the epidemiology, pathophysiology, diagnostics, treatment and preventions was stated in the article making it good literature for the disease itself.
Throughout the article, pulmonary embolism and deep vein thrombosis (and thromboembolism) was referred to, as the latter occurs most of the time before the onset of pulmonary embolism. It has been stated in the article that both may occur at the same time in patients with high risk of developing the disease, thus diagnostic and treatment procedures were mentioned in managing them.
The published literature—a review article in nature, mainly focused on results of clinical trials and other published journals. Though it was stated there medical diagnostics and procedures, it was not clearly mentioned which of it were the advancement in those procedures and which would need further studies. In general, it was able to present details of the disease, making a clear note in the vitality of making correct diagnostics and immediate treatments for reducing mortality among patients.
Tapson, V. F. (2008) Acute Pulmonary Embolism. The New England Journal of Medicine, 358, 1047-1052.