Background: D-dimer levels are used in several clinical settings, such as in predicting venous thrombosis, cardioembolic stroke and cancer status. In the present study, we investigated the associations between plasma D-dimer levels at admission, clinical characteristics and mortality at discharge in cryptogenic stroke patients. We also investigated whether D-dimer levels can predict long-term outcomes in those patients, including those with and without right-to-left shunt (RLS).
Methods: Acute cryptogenic stroke patients (n = 295, 72 ± 13 years old) were consecutively enrolled and retrospectively analyzed. We defined the cryptogenic stroke as an undetermined etiology according to the Trial of Org 10172 in Acute Stroke Treatment criteria. Plasma D-dimer levels at admission were evaluated. Assessments for RLS were performed using saline contrast-transcranial Doppler ultrasonography or contrast-transesophageal echography. Survivors (at discharge) underwent follow-up for up to 3 years after stroke onset.
Results: Of the total enrolled cohort, 17 patients died at discharge. D-dimer levels correlated with initial National Institutes of Health Stroke Scale (NIHSS) score (r = 0.391, P < 0.001) and were associated with mortality at discharge [odds ratio 1.04; 95% confidence interval (CI) 1.00-1.08, P = 0.049] after adjusting for age, sex and initial NIHSS score. Of the 278 survivors at discharge, 266 patients were evaluated to assess RLS during hospitalization, and 62 patients (23.3%) exhibited RLS. According to the median plasma D-dimer levels at admission (0.7 µg/ml), the patients were divided into a low D-dimer group (n = 136, < median) and a high D-dimer group (n = 130, ≥ median). Patients in the high D-dimer group were older, more frequently female, had a lower BMI, had a higher prevalence of cancer and had greater initial neurological severity compared to the patients in the low D-dimer group. During the follow-up period (median, 1093 days), 31 patients developed recurrent stroke and 33 patients died. High D-dimer levels at admission were independently associated with recurrent stroke and all-cause mortality [hazard ratio (HR) 3.76; 95% CI 1.21-14.1, P = 0.021) in patients with RLS, but not in those without RLS (HR 1.35; 95% CI 0.74-2.50, P = 0.335).
Conclusions: Increased D-dimer levels at admission were associated with mortality at discharge in cryptogenic stroke patients. In addition, high D-dimer levels were also associated with long-term outcomes in cryptogenic stroke patients with RLS.
Keywords: Cryptogenic stroke; D-dimer; Outcome.