Heart Attack Treatment (cont.)
Clot-dissolving drugs
While anti-platelet agents and anti-coagulants prevent the formation of blood
clots, they cannot dissolve existing blood clots and hence cannot be relied upon
to open blocked arteries rapidly. Clot-dissolving drugs (also called
fibrinolytic or thrombolytic medications) actually dissolve blood clots and can
rapidly open blocked arteries. Intravenous administration of clot-dissolving
drugs such as tissue plasminogen activator (TPA) or TNK can open up to 80% of
acutely blocked coronary arteries. The earlier these drugs are administered, the
greater the success at opening the artery and the more effective the
preservation of heart muscle. If clot-dissolving drugs are given too late (more
than six hours after the onset of the heart attack), most of the muscle damage
already may have occurred.
If a hospital does not have a catheterization laboratory with the ability to
perform PTCA, or if there are logistic reasons why PTCA will be delayed,
clot-dissolving drugs can be promptly administered to achieve reperfusion. PTCA
then may be performed in patients who fail to respond to the clot-dissolving
drugs. (If prompt PTCA and stenting are available, it has been demonstrated that
they are preferable to clot-dissolving drugs to open arteries.)
Clot-dissolving drugs increase the risk of bleeding enough so that some patients cannot be
treated with them, for example, patients with recent surgery or major trauma,
recent stroke, bleeding ulcer, or other conditions that increases the risk of
bleeding.
Coronary angiography and percutaneous transluminal coronary angioplasty
Coronary angiography and percutaneous transluminal
coronary angioplasty (PTCA) is the most direct method of opening a blocked coronary artery.
The procedures are performed in the catheterization laboratory in a hospital.
Under x-ray guidance, a tiny plastic catheter with a balloon on its end is
advanced over a guide wire from a vein in the groin or the arm and into the
blocked coronary artery. Once the balloon reaches the blockage, it is inflated,
pushing the clot and plaque out of the way to open the artery. PTCA can be effective
in opening up to 95% of arteries. In addition, the angiogram (x-ray pictures
taken of the coronary arteries) allows evaluation of the status of the other
coronary arteries so that long-term treatment plans may be formulated.
For optimal benefits, coronary angiography and PTCA should be
performed as soon as possible. Most cardiologists recommend that the time
interval between the patient's arrival at the hospital and the deployment of
the angioplasty balloon to open the artery should be less than 60-90 minutes.
For best results, the coronary angiogram and PTCA should be performed by an
experienced cardiologist in a well-equipped cardiac catheterization laboratory.
The cardiologist is considered experienced if he or she performs more than 75
such procedures a year. The catheterization laboratory personnel are considered
experienced if the facility performs more than 200 such procedures a year.
It also is important that there be a surgical team to perform immediate open-heart
surgery (coronary artery bypass grafting) in the event that PTCA is unsuccessful
in opening the blocked artery or if there is a serious complication of
PTCA. For example, in a small number of patients, PTCA cannot be performed because
of technical difficulties in passing the guide wire or the balloon across
the narrowed arterial segment. Open-heart surgery also will be necessary if
there is a serious complication such as coronary artery injury during PTCA or an
abrupt closure of the coronary artery shortly after PTCA. These complications may occur in
one to two percent of patients.
The most serious complication of PTCA is an abrupt closure of the coronary
artery within the first few hours after PTCA. Abrupt coronary artery closure
(that can lead to further heart damage) occurs in five percent of patients after simple
balloon angioplasty (without stenting). Abrupt closure is due to a combination
of tearing (dissection) of the inner lining of the artery, blood clotting at the
site of the balloon, and constriction (spasm) or elastic recoil of the artery at
the site where the balloon is inflated. Individuals at an increased risk for
abrupt closure include women, patients with unstable angina, and patients having
heart attacks.
The risk of abrupt closure of the coronary arteries can be reduced if:
- Aspirin is given during or after PTCA to prevent blood
clotting. In fact, virtually all patients are maintained on aspirin
indefinitely after PTCA to prevent arterial clots.
- Anticoagulants such as intravenous heparin are given
during PTCA to further prevent blood clotting.
- Combinations of nitrates and calcium channel blockers are used to minimize coronary artery spasm (see discussion that
follows).
- Coronary artery stents are deployed to minimize
coronary artery closure.
- The glycoprotein IIb/IIIa inhibitors are given.
Next: Coronary artery stents »
- ACE Inhibitors - Read about ACE inhibitors like Altace, lisinopril, enalapril, ramparil, Zestril and more. Information includes side effects, drug interactions, and pregnancy safety information.
- Coronary Artery Bypass Graft - Read about heart bypass surgery (coronary artery bypass graft surgery, CABG) including how coronary artery disease is diagnosed, treated, recovery time, risks and complications, and the long term results after CABG.
- Congestive Heart Failure - Read about congestive heart failure symptoms like fatigue, abdomen, leg and ankle swelling, shortness of breath, sleeplessness, increased urination, nausea, abdominal pain, and decreased appetite.
Latest Medical News
Heart RSS