equipment and small incisions, most heart operations are performed via a
thoracotomy, where the sternum, or chest bone, is split with a saw and the
rib cage is (gruesomely) spread open with a metal cranking device. The
heart and its neighbors lie in full view, accessible to surgeon’s hands and
devices.
Valve surgery is most commonly performed on the aortic valve,
followed by the mitral valve.^34 Recent analysis shows that isolated valve
surgery (operating on one valve in a single operations) occurs 89 percent
of the time, while 11 percent of open-heart valve operations involve a
combination of valve repair or replacements (most commonly the aortic
and mitral valve together).^35
Tricuspid valve surgery, like all valve surgery, entails either repair or
replacement. Tricuspid valve replacement surgery is performed one
thousand times per year in the United States, about half the time in concert
with another heart procedure.^36
There is a significant trend in repairing diseased mitral valves, instead
of replacing them. For those undergoing replacement, there has been a
definite trend in replacing the mitral valve with a xenograph (so called
“bioprosthetic” animal valves) tissue graft instead of a mechanical heart
valve.^37 In cases of repair, permanent sutures and reinforcing implants are
used; therefore, device implantation occurs with repair and replacement.
In 2005 there were a total of 16,997 isolated mitral valve operations in the
United States, with almost an equal distribution of repair and replacement.
Alternatively, in 2005, there were 28,360 isolated aortic valve
operations, with 97 percent valve replacement operations and only 3
percent repair. Almost all the replaced valves are bioprosthetic, with fewer
and fewer mechanical (metal) valve operations every year. In addition, like
other valve operations, where there is a trend in multiple structures
treated, there is an increase in the percentage of patients whose thoracic
aorta is also addressed at the time that their aortic valve is replaced. A
recent study showed 28.5 percent of patients with a bicuspid (congenitally
malformed) aortic valve underwent surgery on their thoracic aorta. This is
a threefold increase from 1998 to 2008, and represents a 7.5-fold increase
in costs from $156 million to $1.2 billion in the same time span.^38 The
Harvard physicians who published this paper were able to demonstrate a
meaningful change in mortality, but the study highlights how a simple