The advances in cardiac surgery have been enormous over the past 20 years. We
have gone from some fairly primitive high-risk surgery, to some very, very
sophisticated interventional techniques, which have given cardiac patients a new
lease of life. In fact, if the techniques that are available now, were able to
be carried out 30 years ago, my father would in all probability, still be alive
today.
However, before getting into modern life-saving techniques, a
short review of cardiac pathology is in order. Myocardial infarction is the
common cause of cardiac muscle death, and finally ours. (Make that “yours” as
I’m not going yet!)
The heart muscle is supplied with oxygenated blood by its own
system of arteries. The heart does not get its oxygen from the blood in its
chambers. Instead, there is a network of ‘heart’ arteries (called the coronary
arteries) which supply the cardiac muscle. If any of these get blocked, this is
known as a “stenosis” or an “occlusion”, which in turn can bring on the coronary
“conclusion”! The death of the muscle is called “infarction”.
The blockage is most often caused by Cholesterol, which gets
deposited on the inside wall of the arteries and is called “plaque”, and then
red cells stick on the surface of the deposit and it builds up from there. If
you have a 50 percent stenosis, you will start to get chest pains on exercise.
If you have a 100 percent stenosis, you may drop dead during the exercise.
To correct this problem, the only way we knew was to carry
out an open heart operation, replace the blocked coronary arteries with vessels
taken from other parts of the body, usually veins from the leg. However, now we
can leave your arteries where they are, but do something to relieve the
stenosis, or blockage. This is called “Angioplasty”.
One way is to send an inflatable balloon to dilate the
blocked area, and this is known as coronary balloon angioplasty. It is more
formally known as percutaneous transluminal coronary angioplasty (PTCA):
percutaneous meaning “through the skin,” transluminal meaning “inside the blood
vessel,” coronary meaning “related to the heart,” and angioplasty meaning “blood
vessel repair.”
Angioplasty involves creating space in the blocked artery by
inserting and inflating a tiny balloon, which compresses some of the blocking
plaque against the arterial wall. When the balloon is deflated and removed, the
plaque still remains compressed, clearing a space in the artery and improving
blood flow. While angioplasty does not always completely clear an artery, more
than 90 percent of all procedures are immediately successful.
There are other techniques available, and the most common is
by using “stents”. This is called percutanous coronary intervention (PCI). The
success in today’s cardiac surgery is due in part to the increased use of these
tiny wire mesh tubes called stents, which cardiologists began using in the 1990s
to help keep arteries open following angioplasty. About 70 to 90 percent of all
angioplasty patients receive a stent, which is inserted permanently at the site
of the blockage.
Stents can be used in a number of ways with angioplasty
procedures. A stent may be inserted during an original angioplasty to prevent
possible arterial collapse and lower the chance of heart attack and re-narrowing
of the artery (called re-stenosis). A stent also may be inserted during a second
angioplasty to prevent recurrent restenosis. Stents can also be used in the
unlikely event that an artery is injured by the catheter. Experienced doctors
are able to install stents in one or more arteries with a high probability of
success.
The use of stents has decreased the abrupt and unpredictable
closure of an artery, which necessitated emergency coronary artery bypass
surgery. Studies show stents are better than angioplasty alone in preventing
re-stenosis, which is one of the most common problems associated with
angioplasty.
Evidence suggests that angioplasty patients are doing better
today because doctors are better able to target blockages, by using such
techniques as the 64 Slice CT, so your interventionist is able to pinpoint the
blockage with greater accuracy. However, we will deal with the 64 Slice CT
technology another week.
