Welcome!
I've been battling the big D since I was 16. I've tried a lot of things, but for the past few years Effexor has been required to keep it at bay.
When I was meeting with the surgeon I asked if I should discontinue the Effexor and she said 'no'. She was emphatic on that point, given that I had such a long history, and was currently in a successful treatment, she was adamant that I not stop it just for the surgery. She cited what many here know, that surgery can bring it on so why would I choose to go off something that works right in time for a possible triggering event. I took it straight through and still do. I had no issues and was thankful for that. I hit a few bumps in my recovery, I'm really happy that I was able to focus just on getting better, and do so without having to battle depression at the same time. I don't know about you but for me battling depression takes/saps so very much of my energy.
Every year or so I stop taking my prescribed antidepressant for a month or more and then when I slip backwards (as always, sigh), I go back on. Maybe someday it'll go into permanent remission, one can only hope.
This is just my experience, the only advice I would give to you is to do whatever works for you and keep at it even through the disruption of the surgery and do so with the full knowledge of the cardiac and primary care team.
I wouldn't get yourself all psych'd out about it, you don't need a self-fulfilling event here. Just like other major life events, surgery can trigger depression. So what, tons of other triggers lurk in every corner, this trigger isn't bigger or badder than the others, it just is.
Tell the Dr's you work with and with their help and if available the help of a supportive 'other' they can help you with any depression that crops up. Think positive, it's going to work out just fine!
Peace,
Ruth