A few points that I think are facts:
1) The new guidelines make a pretty sharp distinction between "normal" HVR patients (including BAVers) who are
pre-op (who USED to pre-medicate but are now told NOT to) and those who are
post-op (who have ALWAYS been told to pre-medicate, and still are).
2) According to my reading, patients with MECH HVs are just as vulnerable to infectious Endocarditis as those of us with TISSUE HVs. Endocarditis attacks the tissues around the valves and causes "vegetative growth" that can clog valves, so I think it's scary for all of us. (@sweetmarie)
3) The guidelines -- old and new -- are just that, GUIDELINES. They are admittedly broad-brush compromise tradeoffs, made in the face of a remarkable lack of hard evidence. (E.g., "Although it has long been assumed that dental procedures may cause IE in patients with underlying cardiac risk factors and that antibiotic prophylaxis is effective, scientific proof is lacking to support these assumptions.") What we DO know is that IE is especially scary for post-op HVR patients, which is why the guidelines (and the surgeons, cardiologists, and dentists) continue to recommend pre-medication for us post-ops, even if there's little or no evidence to show that it helps.
4) The down-side of overuse of antibiotics is not limited to immediate side-effects! As we all know, all humans in 2011 are at increased risk from a growing number of antibiotic-resistant bacterial infections. Offhand, I can think of
C. difficile, MRSA, & some resistant strains of
e.coli, but I think there are lots more. The more we (over-)use antibiotics, the more we "educate" the bacteria to be resistant. Big Pharma is trying to develop new antibiotics to stay ahead of the "arms race", but all the experts seem to think they're falling behind. I BELIEVE that this is both a
collective problem AND an
individual one:
I.e., (1) collectively, if we overdose our feedlot cattle and fish-farm fish with -cyllin drugs, we are all at increased risk. And (2) individually, people who take lots of -cyllin drugs may be at higher risk of "breeding" their own population of "super-bugs" than people who don't.
If that last "belief" is wrong, please correct it, because it's important here. One article --
http://www.bmj.com/content/340/bmj.c2096.full -- says that it's true, and that the effect "is greatest in the month immediately after treatment but may persist for up to 12 months." Since most of us get our teeth cleaned (or worked on) several times a year, we who pre-medicate (and our own "bugs") are apparently more "antibiotic-resistant" than the rest of the population.
DISCLAIMER: I am not suggesting that anybody change their practice, least of all that anybody disobey their doctor's (or doctors') orders, or do anything else. I think the new guidelines are reasonable, and I'm following them. But I'm also very impressed by how little evidence there is behind them.
