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Angioplasty
Angioplasty, also known as percutaneous transluminal
coronary angioplasty (PTCA), is a technique for opening
blocked arteries and treating coronary artery disease.
It is a relatively low risk, low cost, non-surgical
treatment.
To restore normal blood flow, a balloon-tipped catheter
is inserted into the clogged artery, and is then inflated.
The inflated balloon compresses the plaque against the
artery wall, making more room for blood to flow. The
balloon is then deflated and removed. Opening the artery
will not result in a completely plaque free artery,
but the plaque will be compressed so blood can pass
through the vessel.
In order to keep the plaque from closing the artery
again, a coronary stent
may be used to hold the plaque in place. The stent is
a metal mesh tube that is placed at the blockage site
during angioplasty.
In approximately 20 to 25 percent of stents, scar tissue
may develop around the area of the stent, causing restenosis
- (a new blockage) within six months of treatment. If
this occurs, the doctor can reopen the vessel by angioplasty
and then use vascular brachytherapy to prevent another
blockage.
Recent developments in stent technology have included
the drug-eluting (drug-coated)
stent. The drug-eluting stent is coated
with a drug, Sirolimus, that is released over time.
The drug inhibits the development of scar tissue around
the area of the formerly blocked artery, reducing reocclusion
to approximately 5 percent.
There have been some concerns by consumers and the
media about risks associated with the drug-eluting stent.
The consensus from the medical community is that if
drug-eluting stent recipients receive a prescription
platelet inhibitor medication for six months following
the placement of the stent, the risks are minimized.
Plavix or, in some cases Ticlid, is prescribed.
How is a Coronary Stent
Implanted?
Distal Protection
Distal Protection is also known as temporary balloon
occlusion and aspiration, and is a relatively new treatment
for opening occluded coronary bypass vessels. Coronary
bypass surgery provides a new pathway for blood to travel
through the heart. A vein from the leg, known as a saphenous
vein, is removed and grafted between the aorta and the
blocked artery providing an alternate route for blood
to flow. Many times, an aging saphenous vein itself
becomes blocked; this typically happens between 10-15
years (50 percent are blocked by the 10 year mark) after
the original graft. When angioplasty is used to open
these blockages, tiny particles can break off the arterial
wall and be carried further down the artery causing
an occlusion of the vessel at another location. Between
10 and 20 percent of the time, this "debris"
causes serious problems-- namely, a heart attack.
Distal protection substantially minimizes the risk
of floating debris which can break off during angioplasty.
Working from outside the body through a small incision
in the patient's groin, the physician maneuvers a thin,
hollow tube (about .014 of an inch in diameter) into
the blocked saphenous vein graft vessel. The tube carries
a net-like mechanism at its tip (figure 1) that is opened
to catch any floating debris (figure 2).
The physician then performs an angioplasty/stent procedure.
The debris particles are caught in the net. The net
is then closed with the debris still inside it and removed
(figure 3).
Combined tPA Therapy
The clot busting drug tPA has been used for many years
as a treatment following heart attacks, and more recently
in the treatment of strokes. Now, recent studies suggest
that the use of very low doses of tPA combined with
balloon angioplasty is a highly effective treatment
option. Using tPA, studies suggest, is not only cost
effective, but may even allow doctors to salvage highly
diseased arteries.
Implantable cardioverter defibrillator (ICD)
Similar to a pacemaker, a battery-operated ICD is implanted
in the body and contains a microprocessor and has wires
connected to the heart to monitor and record heart rate.
The ICD delivers potentially life-saving electrical
shocks to counteract lethal arrhythmias. These devices
may also be used for patients with certain types of
tachycardia (heart beats too fast).
Pacemakers
A pacemaker signals the heart to beat when it is too
slow. It is made up of an electrical-pulse generator
and one-two wires, which deliver electrical impulses
to the heart. The wires can also carry signals from
the heart. The pulse generator interprets these signals,
determines the heart's activity and responds to its
needs.
Radiofrequency Ablation
Another option for some arrhythmia patients, that is
up to 95 percent effective. Ablation means "elimination,"
and that's what this technique does to tissue involved
in certain types of arrhythmia. As with an electrophysiology
study, radiofrequency ablation involves the threading
of electrode catheters, guided by x-ray, into the heart.
The electrophysiologist "maps" the electrical
signals and locates the arrhythmia source. Then, radiofrequency
energy (electromagnetic radio waves) is directed to
that precise spot, destroying the tissue and, thus,
permanently ending the arrhythmic episodes.
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Treatment
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