- Stroke or CHD patients who are diagnosed within 6 months. CHD patients are identified by being diagnosed by coronary arteriography or coronary CT angiography, having received coronary stent or coronary artery bypass surgery, or being diagnosed with acute myocardial infarction. Stroke patients are identified by being diagnosed with cerebral thrombosis, cerebral embolism, cerebral hemorrhage, subarachnoid hemorrhage or transient ischemic attack.