Ischemic stroke occurs when a clot blocks an artery that supplies blood to the brain. Strokes such as this can impair brain function, resulting in disability or death. According to American Heart Association statistics, the annual incidence of stroke in the United States is 795,000 and the total number of people who have survived strokes is estimated to be 6.5 million. Almost 70% of attacks occur in persons aged 65 years and older and ischemic stroke accounts for approximately 88% of strokes in the United States. Tools for assessment of stroke risk have been developed and used to select patients for preventative treatments; however, a joint committee of the American Heart Association and American Stroke Association has stated that more research is needed to validate existing risk assessment tools and to determine whether recently identified risk factors can improve
the accuracy of these tools. One such recently identified risk factor is elevated levels of lipoproteinassociated phospholipase A2 (Lp-PLA2), an enzyme that can activate inflammation and promote narrowing and hardening of the arteries.