Application of D-dimer to aid in diagnosis of acute aortic dissection

Introduction: Acute aortic dissection (AAD) is an emergent, relatively uncommon condition that typically presents with sudden onset severe chest or back pain. Advanced imaging, such as computerized tomography, is currently the gold standard to diagnose AAD; this can be expensive and unavailable at all health care centers. D-dimer is a blood test that has been shown in recent studies to be elevated in acute aortic dissection. This may be a more cost-effective way to help the clinician “rule-out” an acute aortic dissection. Objective: The purpose of this research was to determine if there is significant data regarding the sensitivity and specificity of a D-dimer in the use of diagnosing an acute aortic dissection. Methods: A PubMed search was conducted utilizing the following terms and filters: “aortic dissection” and “D-dimer. ” Articles were screened and assessed for eligibility based on sample size, evaluation of sensitivity and specificity of d-dimer, and if D-dimer was the only independent factor being examined in diagnosis of an AAD. Results: Our search resulted in one retrospective observational study, one prospective observational study, and one meta-analysis. Conclusion: In a patient presenting to the Emergency Department with symptoms suspicious of an acute aortic dissection, a D-dimer level less than 500ng/ml may be a useful tool to decrease the likelihood of the disease and reduce the need for advanced imaging. The D-dimer is not shown to be specific for acute aortic dissection. The addition of a D-dimer as a first line test may be a quick tool to help a clinician adjust their differential diagnoses to determine the need for imaging. Introduction Acute Aortic Dissection (AAD) is a tear in the wall of the aorta. As the tear extends, blood can flow in between the layers of the blood vessel wall, which leads to ischemia to nearby organs or aortic rupture; both abrupt and lethal. AAD often presents with severe chest pain and acute hemodynamic compromise; however, the symptoms can be vague, making the disease privy for misdiagnosis and malpractice. Currently, the gold standard to diagnose AAD is the use of imaging which includes the following methods: computed tomography (CT), magnetic resonance angiography (MRA), and transesophageal echocardiogram (TEE). Each of these imaging techniques has its own risk associated with them for the patient. CT exposes patients to radiation and also uses contrast dye which is harmful to the kidneys. MRA also uses contrast dye meaning patients with renal disease may not be able to undergo the test. TEE is a moderately invasive procedure which includes the risk of esophageal perforation, and the patient is also under conscious sedation. Due to the lethality of AAD, most patients presenting with chest pain will undergo imaging to rule out AAD; however, due to the rarity of AAD, most of the imaging is negative as the prevalence/incidence of AAD is 3.5 per 100,000 person per year, which uses time, resources, and money. It is difficult to perform imaging as the initial diagnostic test due to high cost, radiation exposure, and the high volume of patients who present with a chief complaint of “chest pain. ” D-dimer is degradation product of fibrin, whose serum level is elevated in AAD, venous thromboembolism (VTE), and other conditions. Collecting a quick, serum blood D-dimer would be a faster, more cost-efficient method to rule out AAD. In the past 20 years, increased research has displayed diagnostic accuracy of D-dimer for AAD, with a sensitivity at 0.97 and sensitivity of 0.64. The high sensitivity indicates a negative D-dimer which could theoretically rule out AAD. Using the cutoff value of 500ng/ml, the same value used to rule out venous pulmonary embolism (PE), has been repeatedly used with consistent results. We analyzed three studies to assess the role of a negative D-dimer in the workup in patients suspected of an AAD to eliminate the use of unnecessary imaging.