What Are The Precautions To Be Taken To Prevent Recurring UTIs?

Question : I just had minimally-invasive aortic valve replacement surgery (16 XXXXXXX 2015); damaged valve replaced with animal valve. I was almost asymptomatic except for extreme fatigue and some swelling in my ankles. One doctor asked did I know I had a "heart murmer." That question sent me to a cardiologist who diagnosed through an echocardiogram that I had aortic valve stenosis. MY QUESTION: How do I go forward to deal with infections—especially UTIs that are also mostly asymptomatic for me—and dental procedures. Please Note that I had the 'bladder sling' sugery about 10 years ago, and have had UTI problems ever since. My family doctor has often NOT prescribed antibiotics when I knew I needed them, leaving me to fight off some pretty major infections on my own. My heart surgeon almost made me feel bad for having this surgery after I told him I often have UTIs and dental problems and never know it. Said I was endangering my brand new pig valve. Well, I suppose, BUT my cardiologist said it was a good thing I had this surgery because my heart had adapted just about as much as it could (whatever that means). SECOND QUESTION: Do I need to get a better urologist and family doctor who will pay attention to MY particulars?