hi and welcome well do not know what is the age of your brother and what are the associated risk factors , like diabetes or hypertension, currently smokes . more importantly what were the findings of the angiography and were there any stents placed and were they drug eluting stents (DES) ecosprin .... is it only aspirin 15o mg or does it contain clopidogrel also. if stents are placed, normally 1 year of aspirin and clopidogrel is prescribed and after that if all goes well , then only aspirin is continued for the rest of your life. these medicines also do irritate stomach causing problems , but if after discontinuing them causing chest pain it should be investigated , in your case re angiogram was done was done and clear ( swelling of arteries is not clear better explain using the medical terms mentioned in the angiogram report please ). no need to worry then , its better to see for his symptoms in terms of exercise and daily activity capacity and consult cardiologist . using aspirin ( coated ) does not irritate stomach and can be an option ...get an ETT done to see if there are any other changes in ecg during exercise , but were his cardiac markers elevated during this recent attack , if yes it means he had a fresh event and leaving medications can be dangerous. if previously he was high risk patient and poor control of his daily life style and food , then stopping these medications could have been the cause , but if a new vessel is involved then the patient should be re evaluated , especially control of his BP and cholesterols . its now ideal to discuss the whole issue in detail with a consultant cardiologist ... our community has also been reported to have resistance to clopidogrel , discuss with your doctor. take care