Single subcortical infarction associated with parental arterial disease: important yet neglected sub-type of atherothrombotic stroke.

BACKGROUND: Traditionally, single subcortical infarction has been considered to be caused by lipohyalinosis of small perforating arteries. However, atherosclerosis in the parental artery produces similar single subcortical infarction by blocking the orifice of branching arteries. The purpose of this paper is to review the evolving concepts, clinical characteristics, and classification issues of single subcortical infarction associated with parental artery disease. SUMMARY OF REVIEW: Single subcortical infarction associated with parental artery disease is an important cause of subcortical infarction, more so in the posterior than in anterior circulation stroke. It is one of the major causes of brainstem infarction. Single subcortical infarction associated with parental artery disease seems to be common in Asian population where intracranial atherosclerosis is prevalent. Although the clinical characteristics of single subcortical infarction associated with parental artery disease are similar to single subcortical infarction caused by small artery disease, single subcortical infarction associated with parental artery disease is more often associated with characteristics of atherosclerosis, and fluctuating and poorer outcomes. With advanced imaging techniques such as high-resolution cross-sectional magnetic resonance imaging, single subcortical infarction associated with parental artery disease emerges as an even more important stroke sub-type. Nevertheless, it has been neglected in previous stroke sub-type classifications, being erroneously classified as small artery disease or cryptogenic stroke. Prevention and treatment trials focusing on single subcortical infarction associated with parental artery disease are not available.
CONCLUSION: Single subcortical infarction associated with parental artery disease is an important stroke sub-type, distinct from small artery disease, illustrating that greater efforts should be made in its accurate diagnosis. Studies are needed to investigate the prevalence of single subcortical infarction associated with parental artery disease in various parts of the world and to design a stroke classification system that includes single subcortical infarction associated with parental artery disease. Prevention and treatment trials should consider this important sub-group of stroke, so that tailored strategies can be applied in clinical practice.