Quantitative D-dimer is a common screening tool to rule-out pulmonary embolism in low-risk population but is there more that it can tell us?
Yes, there have been studies linking increasing d-dimers to: 1) likelihood of PE, 2) location of PE, and 3) clot burden.
1. The level of d-dimer has been shown that with increasing d-dimer magnitude, there is an increasing chance of diagnosing pulmonary embolism by computed tomography with correlatory values as follows (as published by Kaush)[1]:
D-Dimer % with PE
0.58-1.0 3.6%
1.0-2.0 8.0%
2.0-5.0 16.2%
5.0-20 35.3%
>20 45.5%
2. There have also been some studies showing correlation between d-dimer magnitudes and location of clot, showing the higher the d-dimer, the more likely the PE is proximal/main (median >5.0) pulmonary artery vs. lobar vs. segmental [2].
3. Higher d-dimer values showing higher clot burden as calculated by CT clot burden scoring for d-dimer values >4.0 (avg clot score 10 vs. 5) [3]. However, clot scoring varies in its predictive value of outcomes and is not a reliable predictor of patient mortality [4,5,6].
References
1. Shah K, Quaas J, Rolston D, Bansal S, Bania T, Newman D, Wiener D, Lee J.
Magnitude of D-dimer matters for diagnosing pulmonary embolus. Am J Emerg Med.
2013 Jun;31(6):942-5.
2. Jeebun V, Doe SJ, Singh L, Worthy SA, Forrest IA. Are clinical parameters and
biomarkers predictive of severity of acute pulmonary emboli on CTPA? QJM. 2010
Feb;103(2):91-7.
3. Hochuli M, Duewell S, Frauchiger B. Quantitative d-dimer levels and the extent
of venous thromboembolism in CT angiography and lower limb ultrasonography. Vasa.
2007 Nov;36(4):267-74
4. Subramaniam RM, Mandrekar J, Chang C, Blair D, Gilbert K, Peller PJ, Sleigh J,
Karalus N. Pulmonary embolism outcome: a prospective evaluation of CT pulmonary
angiographic clot burden score and ECG score. AJR Am J Roentgenol. 2008
Jun;190(6):1599-604
5. Venkatesh SK, Wang SC. Central clot score at computed tomography as a
predictor of 30-day mortality after acute pulmonary embolism. Ann Acad Med
Singapore. 2010 Jun;39(6):442-7
6. Furlan A, Aghayev A, Chang CC, Patil A, Jeon KN, Park B, Fetzer DT, Saul M,
Roberts MS, Bae KT. Short-term mortality in acute pulmonary embolism: clot burden
and signs of right heart dysfunction at CT pulmonary angiography. Radiology. 2012
Oct;265(1):283-93
