Is there an age-adjusted cutoff for D-dimer (D-dimer) levels in diagnosing aortic dissection?

From the Guidelines

There is no established age-adjusted cutoff for D-dimer specifically for aortic dissection, and the standard cutoff of 500 ng/mL is typically used regardless of age. While age-adjusted D-dimer cutoffs exist for pulmonary embolism, these have not been validated for aortic dissection. D-dimer testing can be helpful in aortic dissection with high sensitivity (>95%) but limited specificity, meaning elevated levels support further imaging but normal levels don't definitively rule out dissection in high-risk patients.

Key Points

• The 2022 ACC/AHA guideline for the diagnosis and management of aortic disease recommends CT as the initial diagnostic imaging for suspected aortic dissection, with TEE and MRI as reasonable alternatives 1.
• D-dimer testing is not diagnostic but can be useful in excluding the diagnosis of aortic dissection in patients with a low pre-test probability, with a cutoff of 500 ng/mL typically used 1.
• Clinical assessment using risk factors and presentation remains crucial, as D-dimer should be considered an adjunctive test rather than the primary diagnostic tool for aortic dissection, especially in elderly patients who often have elevated D-dimer levels from various causes.

Diagnostic Approach

• For suspected aortic dissection, definitive diagnosis requires advanced imaging such as CT angiography, MRI, or transesophageal echocardiography.
• A plain chest x-ray is neither sufficiently sensitive nor specific for aortic dissection to be used as a diagnostic tool, but certain radiographic findings may raise suspicion of aortic dissection or suggest an alternate diagnosis 1.
• Acute aortic dissection risk scoring systems, such as the aortic dissection detection risk score (AAD-RS) or the aorta simplified score (AORTAs), can aid in the diagnostic evaluation of patients presenting with suspected aortic dissection, but have not been uniformly adopted 1.

From the Research

Age-Adjusted D-Dimer Cutoff for Aortic Dissection

• The use of age-adjusted D-dimer cutoffs has been explored in several studies to improve the diagnostic accuracy of aortic dissection 2, 3.
• A study published in the Journal of the American Heart Association in 2021 proposed an age-adjusted D-dimer cutoff calculated as years/age × 10 ng/mL (minimum 500) 2.
• Another study published in Emergency Medicine International in 2022 used an age-adjusted D-dimer cutoff of age × 0.01 in patients over 50 years, which increased specificity and positive predictive value while maintaining high sensitivity 3.
• Other studies have also investigated the diagnostic value of D-dimer in acute aortic dissection, with some suggesting that a cutoff of 500 ng/mL may be useful for ruling out the condition 4, 5, 6.

Diagnostic Accuracy of Age-Adjusted D-Dimer

• The studies suggest that age-adjusted D-dimer cutoffs may improve the diagnostic accuracy of aortic dissection, particularly in terms of specificity and positive predictive value 2, 3.
• However, the optimal age-adjusted cutoff value and the clinical utility of this approach require further investigation.
• The use of age-adjusted D-dimer cutoffs may be considered as part of a diagnostic strategy for aortic dissection, particularly in combination with pretest probability assessment tools such as the aortic dissection detection risk score 6.

Key Findings

• Age-adjusted D-dimer cutoffs may improve the diagnostic accuracy of aortic dissection 2, 3.
• The optimal age-adjusted cutoff value requires further investigation.
• The use of age-adjusted D-dimer cutoffs may be considered as part of a diagnostic strategy for aortic dissection, particularly in combination with pretest probability assessment tools 6.