The study focus on the elderly patient (older than 80 years of age) who had acute ischemic stroke and received mechanical thrombectomy. The investigators analyze different factors in the stage of before, between, after procedure and trying to figure out if there is any difference between the 30-day-mortality group versus non-30-day-mortality group.

With the constant improvements in health care, standard of living and the decrease birth rate, the percentage of the elderly population ( above 80 years old) is expected to double in Taiwan by the year 2044, according to data from the National Development Council. Consequently with the increase in the proportion of senior citizens, there will be an surge number of patient suffering from cardiovascular and cerebrovascular diseases, most importantly acute ischemic stroke. In recent years, mechanical thrombectomy has become the gold standard in the treatment for acute stroke patients, however, many studies have excluded the patients above the age of 80 years old as the benefits of the procedure have been very controversial and there is no clear evidence proving favorable a outcome. There are a few studies which state that though elderly patients had higher risk of complications when receiving mechanical thrombectomy as compared to younger patients, the prognosis was still superior to those didn't receive any intervention. Previous studies put more emphasis on the overall prognosis, morbidity and mortality rate, they didn't focused on the cause of mortality.

The study focuses on analyzing of the cause of mortality and whether there is a significant difference between 30-day-mortality group versus non-30-day-mortality group.

Inclusion criteria:

1. elderly (older than 80 years old)
2. acute ischemic stroke in anterior circulation
3. NIHSS more than 8

Exclusion Criteria:

1. posterior infarction
2. ASPECT score less than 3

1. elderly (older than 80 years old)
2. acute ischemic stroke in anterior circulation
3. NIHSS more than 8