The code would be "I63.9".
This is according to the 2017 ICD-10-CM Codes.
ICD-10-CM stands for International Classification of Diseases, Tenth Revision, Clinical Modification.
After going to an index for these codes you should select:
Step 1. Diseases of the circulatory system I00-I99
Step 2. Cerebrovascular diseases I60-I69
Step 3. Cerebral infarction I63
Step 4. Choose I63.9 because there are no more specifications on the case as for its origin .