Prognosis for Cryptogenic Cerebrovascular Disease: Good, Bad, or Ugly?

Seemant Chaturvedi, MD reviewing Li L et al. Lancet Neurol 2015 Jul 27.

The burden of atherosclerosis risk factors is lower in patients with cryptogenic stroke than in those with other stroke subtypes.

Despite the performance of diagnostic tests such as brain computed tomography and carotid ultrasound, up to 30% of transient ischemic attack‎s (TIAs) and strokes may not have a definite etiology but appear to be embolic. These events are classified as “cryptogenic” TIA or stroke. Researchers conducted this study to compare the risk factor profile, prevalence of atherosclerosis and cardioembolism, and short- and long-term outcomes of cryptogenic stroke with other strokes.

They enrolled 1607 patients with stroke and 948 patients with TIA from the longitudinal Oxford Vascular Study and followed them for up to 10 years. Overall, 812 cases (32%) were classified as cryptogenic according to the Trial of Org 10172 in Acute Stroke Treatment (TOAST) system.

Patients with cryptogenic TIA or stroke had a lower frequency of atherosclerosis risk factors than other groups. Relative to large-artery TIA or stroke, cryptogenic patients had significantly less hypertension (age and sex-adjusted odds ratio, 0.41), diabetes (OR, 0.62), and hyperlipidemia (OR, 0.53). Compared with patients who had small-vessel disease or large-artery stroke, the proportion of cryptogenic stroke patients who were dead or dependent (modified Rankin Scale score >2) at 6 months was similar (23% of the cryptogenic group vs. 27% for the other groups). Patients with cryptogenic stroke/TIA had a lower risk for early recurrent stroke compared with other stroke subtypes (adjusted hazard ratio, 0.47).

Citation(s):

Li L et al. Incidence, outcome, risk factors, and long-term prognosis of cryptogenic transient ischaemic attack and ischaemic stroke: A population-based study. Lancet Neurol 2015 Jul 27; 14:903.