Can blood d-dimer levels predict outcome after stroke?

This study evaluated whether the presence of the blood clot breakdown product, d-dimer, is a predictor of poor outcome after ischemic stroke. 

A stroke occurs when there is a disturbance of blood supply to a part of the brain. This can be caused by a blood clot in the brain (ischemic stroke) or a burst blood vessel (hemorrhagic stroke). Both types of stroke lead to a lack of oxygen and food reaching the brain tissue, resulting in cell death.

After an ischemic stroke, patients are given anticoagulants to breakdown the clot that is causing the blood flow disturbance. A blood clot is broken down via a pathway that yields d-dimers in the blood. However, the amount of d-dimers released into the blood can tell you if there is a blood-clotting problem. It has been suggested that modestly elevated blood levels of d-dimer values reflect minor increases in blood coagulation (thickening of blood), thrombin formation (clot formation), and increased production of fibrin (protein involved in clot formation) and that these may be associated with poorer outcome. 

Blood d-dimer concentrations were determined in 220 patients. Brain function deficit (abnormal functioning of the brain) was measured upon admission and blood d-dimer levels were measured the next morning after hospital admission. Imaging of the size of brain region affected was measured with MRI. Patients were followed up 90 days after which functional outcome (favorable or unfavorable) and mortality were measured. Patients were excluded if they had received anticoagulation treatments before admission.

The results showed that there was a positive association between levels of d-dimers and brain function deficit score and the size of brain area affected. In the 69 patients with an unfavorable functional outcome, d-dimer levels were higher compared with d-dimer levels in patients with a favorable outcome. The study concluded that d-dimer levels were found to be an independent predictor for unfavorable functional outcome and mortality. 

The authors concluded that measuring d-dimer levels may be useful in predicting outcome and mortality 90 days after ischemic stroke. 

The small sample size and short follow up of the study gives rise to high imprecision in estimating the effect of d-dimers. This would be minimized with a larger sample size and further follow up studies. 

If you are concerned about the outcome of a stroke, talk to your doctor about measuring blood d-dimer levels, which may give you a better picture of how you are doing.