The federal government has started a Hospital Compare site which you can find by going to the site below or through Medicare. It rates satisfaction in a couple dozen areas. Consumer Reports has a similar site but you have to join to access it. Ratings are average except for bad ones in explaining how to use medications prescribed in the hospital and readmissions.
If you want to know why your operation was aborted, your own doctor can find out. Or contact the surgeon. My guess, from what you wrote, is that your heart stopped and they felt the operation wasn't necessary for survival and didn't want to risk your dying on the table from heart failure. Have your heart checked out. Check for a hospital ombudsman-the person who helps patients with their concerns or the social work section of the hospital.