Use of specialized coagulation testing in the evaluation of patients with acute ischemic stroke

To investigate the use and appropriateness of specialized coagulation tests in the evaluation of patients with acute ischemic stroke and identify factors that influence test ordering.

Coagulation abnormalities are a rare but recognized cause of ischemic stroke.

Patient demographics, stroke risk factors, history of venous thrombosis or miscarriage, family history of stroke, and the results of specialized tests for coagulation disorders were recorded for a consecutive series of ischemic stroke patients over age 18 admitted to an academic medical center over 3 years (n = 674). Factors associated with testing were identified with univariate analyses in a random sample of two-thirds of the patients (n = 450). Multivariate logistic regression modeling was then used to identify variables independently associated with testing and then validated in the remaining patients (n = 224).

Of the 31% of patients (n = 208) tested for coagulopathies, 29% (n = 60) were tested when the result was unlikely to influence therapeutic decisions. Historical factors associated with an increased incidence of a coagulopathy, such as history of venous thrombosis or miscarriage, were not commonly documented. The absence of small-artery atherosclerosis (OR 0.36, 95% CI 0.17 to 0.76) and younger age (OR 0.89 per year, 95% CI 0.87 to 0.92) were independently related to the frequency of specialized coagulation testing.

One-third of specialized coagulation tests were ordered when the test results were unlikely to affect therapeutic decisions. Age was the only clinical factor increasing the likelihood of a coagulopathy that appeared to influence ordering of specialized coagulation tests.