From the Guidelines
D-dimer has limited utility in diagnosing aortic dissection and should not be used as a standalone test. While elevated D-dimer levels are often present in aortic dissection, this finding lacks specificity due to its elevation in many other conditions, including pulmonary embolism, deep vein thrombosis, infection, malignancy, and recent surgery 1. The test has reasonable sensitivity but poor specificity for aortic dissection. According to the most recent guidelines, a negative D-dimer result may help exclude aortic dissection in low-risk patients, but a positive result requires confirmation with definitive imaging studies such as CT angiography, MRI, or transesophageal echocardiography 1.
Key Points to Consider
- D-dimer levels can be elevated in various conditions, making it non-specific for aortic dissection 1.
- The sensitivity of D-dimer for aortic dissection is reasonable, but its specificity is poor 1.
- A negative D-dimer result may be useful in excluding aortic dissection in low-risk patients, but it should not be relied upon in high-risk individuals 1.
- Immediate advanced imaging should be pursued when aortic dissection is suspected based on symptoms, rather than relying on D-dimer results, due to the high mortality rate of untreated aortic dissection 1.
Clinical Practice Recommendations
- Do not use D-dimer as a standalone test for diagnosing aortic dissection.
- Consider D-dimer in the context of clinical suspicion and other diagnostic tools.
- Pursue immediate advanced imaging (CT angiography, MRI, or transesophageal echocardiography) when aortic dissection is suspected, especially in high-risk patients 1.
From the Research
Role of D-dimer in Diagnosing Aortic Dissection
- D-dimer has been reported to be elevated in acute aortic dissection, suggesting its potential use as a "rule-out" marker 2.
- A study found that D-dimer levels were markedly elevated in patients with acute aortic dissection, and a cutoff level of 500 ng/mL could reliably rule out aortic dissection within the first 24 hours after symptom onset 2.
- However, another study noted that D-dimer cannot be recommended as the sole screening tool for acute aortic dissection due to its elevation in other acute chest diseases and the presence of a subset of patients with acute aortic dissection who develop intramural hematomas with low or negative D-dimer levels 3.
Diagnostic Accuracy of D-dimer
- A systematic review and meta-analysis found that D-dimer had a high sensitivity (98.0%) and negative likelihood ratio (0.05) for ruling out acute aortic dissection, but its specificity (41.9%) and positive likelihood ratio (2.11) showed significant statistical heterogeneity 4.
- The meta-analysis suggested that a negative D-dimer result may be useful to help rule out acute aortic dissection in low-risk patients, with a posttest probability of 0.3% in a low-risk population 4.
- Another study found that D-dimer testing had a sensitivity of 100% in patients with acute aortic dissection, with a mean value of 9.4 μg/mL and a range of 0.63 to 54.7 μg/mL 5.
Clinical Applications
- D-dimer testing may be useful in risk stratifying patients with suspected aortic dissection to rule out aortic dissection if used within the first 24 hours after symptom onset 2.
- Elevated D-dimer values can provide hints of the coexistence of acute myocardial infarction and type A aortic dissection, particularly in patients with eccentric aortic regurgitation by transthoracic echocardiography (TTE) 6.
- The combination of TTE and D-dimer testing may help bring the hidden diagnosis of acute aortic dissection to the forefront in patients with initial presentation of acute myocardial infarction 6.