Hello, Thanks for writing to Health Care magic, I am Dr , Muhammad Ahmad , I have read your question closely, I understand your concern and will be helping you with your health related problem. Dilation of aorta is irreversible and it can only be treated by surgery. A vascular surgeon considers many merits and de merits while deciding for surgery, he looks at patient s age , co morbids, dilation of aorta, prognosis, facilities available and local practices, so by just knowing the measurement if dilation it can not be safely advised , when exactly should you get the surgery. I would suggest you to follow what your doctor suggests you to do , yes you always have option to take second opinion but always get it after meeting the doctor in person with all your records, only after a complete examination a doctor can correctly evaluate you for surgery. In general At 4cm we can ask a patient to wait but if symptoms are getting worse, dilation is getting worse, patient ha other co morbid which might make his condition worse, we ask for surgery sooner. I hope this answered your question, If you have more queries I am happy to answer you. Regards. Dr.Muhammad Ahmad