At the 31st Charing Cross International Vascular Surgery Congress, hosted by the Royal College London, which just concluded in early April 2009, Professor Charles McCollum from the University of Manchester pointed out that multiple microemboli in the brain are an important cause of dementia, based on years of research. Such multiple microembolisms in the brain are common in people with dementia. Approximately 24,000,000 people in the world suffer from dementia, Alzheimer`s disease, and vascular dementia accounts for more than 90% of these cases. However, the pathophysiological mechanisms of brain damage in these dementia patients are still being studied. Atherosclerotic stenosis of the carotid arteries is an important cause of multiple microembolisms in the brain, i.e., due to the detachment of sclerotic plaque debris within the carotid arteries, and such multiple microembolisms are frequently asymptomatic. Larger emboli or emboli in certain areas are more clinically symptomatic and are clinically referred to as ischemic cerebral infarction. Carotid artery sclerosis stenosis increases the chance of cerebral infarction, which is an important cause of dementia. In addition this multiple microembolism can also lead to the development of dementia through diffuse brain damage. This finding stems from the memory loss of patients due to multiple cerebral emboli often seen in cardiac surgery due to cardiopulmonary bypass. Also in hip surgery in patients with unclosed foramen ovale, emboli can enter the cerebral circulation when thrombosis is unavoidable. There is also the YAMIS study (Young Adult Myocardial Infarction and Ischemic Cerebral Infarction), which similarly showed that patients with an unclosed foramen ovale are prone to cross-over emboli, leading to cerebral infarction. In Doppler ultrasound quantification of emboli in 170 patients with Alzheimer’s disease and vascular dementia and 170 age- and sex-matched controls, it was found that there was a right-to-left shunt in 32% of patients with Alzheimer’s disease and 29% of patients with vascular dementia-suggesting an unclosed foramen ovale, but only 22% and 20% of controls. Further in transcranial Doppler one-hour monitoring, spontaneous cerebral emboli were found in 40 percent of patients with Alzheimer’s disease and 37 percent of those with vascular dementia, compared with 15 percent and 14 percent of controls. ”This was not statistically significant, but found a striking link between spontaneous brain emboli and dementia,” McCollum said, “which means that if monitored for more than a few hours, most patients with dementia should have spontaneous brain emboli.” In 144 patients with dementia followed at 6-month intervals for 2 years, evaluation of the effect of spontaneous brain emboli on the course of dementia using the Alzheimer’s Disease Assessment Scale Cognitive subscale (ADAS-cog) scoring system found that in patients with spontaneous brain emboli patients, the ADAS-cog progressed from 22.9 to 30.0 at 6 months compared with 23.2 and 26.5 for those without spontaneous brain emboli, but this trend was no longer statistically significant at 2 years.