Question: After many years of counseling, I am confirmed as transgender by my therapist. I am looking for information about the risks associated with hormone treatment given the fact that I have a mechanical heart valve
A quick summary: I had a Bentall procedure on XXXXXXX 10, 2012. I have a Carbomedics CP29 mechanical valve and stent. My current anti-coagulation therapy consists of warfarin plus 81mg ASA daily, and my target INR is 2.0 to 3.0. I am consistently within my therapeutic range. In addition to my heart valve and anticoagulation, I have high blood pressure (under control). For that I am on Coversyl (6mg/day) and 12.5mg of hydrochlorothiazide. I am also on Bisoprolol (10mg/day). I do not smoke, nor have I ever. I am 6 feet tall and currently 223 lbs and attempting to lose weight at a rate of 1lb/week through better eating and moderate exercise (so far, so good).
I have done extensive research on the internet (reputable medical sites only) to determine risks associated with estrogen and clotting. The information I have found basically says that oral estrogen is out of the question for me because of increased risk of DVT – although the literature also carries a proviso that anticoagulation would offset that risk. So it is a little unclear to me whether or not I personally would have an increased risk given my situation.
Several other studies I found however state that transdermal delivery of estrogen carries much lower risk for clotting than oral delivery. The question I still had was whether or not transdermal still had an elevated clotting risk compared to no estrogen therapy at all. I found one study ( http://onlinelibrary.wiley.com/doi/10.1111/j.1538-7836.2010.03953.x/full ) that shows no statistically significant difference in thrombin time between transdermal estrogen delivery and those who had no hrt therapy at all (overlapping confidence intervals). However, oral delivery was significantly different.
I am hoping my research finds that transdermal delivery of estrogen would carry minimal risk of clotting for a mechanical heart valve.
So my question is: I know that you cannot guarantee anything but can you comment on the increase in clotting risk that I might be assuming if I was to proceed with hormone replacement therapy? And if possible, can you quantify how much risk that may be (i.e. 1%, 2%, 10% etc)?

Is there a difference in the actual mechanism that creates DVT type clots and those which may form around a mechanical heart valve (note, mine is a 3rd generation bi-leaflet style in the aortic position, which is supposed to be the lowest TE risk category for heart valves). In essence, do clots form in the same way at a mechanical source and blood vessels, or is there a difference?

So with any valve replacement there is a risk of endothelium damage from changes in blood flow. Understood. Does estradiol aggravate that possibility or is that purely a function of the mechanics of the valve and/or turbulent blood flow in the area?

I am confused. The first answer was that there was no risk with transdermal estrogen and that I could proceed. The last answer suggests that estradiol increases my risk because it helps to repair endothilium damage caused by mechanical heart valve turbulence etc. Can you explain this in more detail because the answers seem contradictory? Thank you.