• Highlights
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• Treatment
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• Surgery
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Heart attack and acute coronary syndrome

Description

An in-depth report on the causes, diagnosis, treatment, and prevention of heart attack.

Alternative Names

Acute coronary syndrome; Myocardial infarction

Surgery

Percutaneous transluminal coronary angioplasty and coronary artery bypass graft surgery are the standard operations for opening narrowed or blocked arteries. They are known as revascularization procedures.

• Emergency angioplasty is the standard procedure for heart attacks and is more effective than the use of thrombolytic drugs for most patients. Unfortunately, not all communities have the facilities for emergency angioplasty. (A 2002 study suggested that in spite of the delay, transporting patients to facilities where angioplasties are available may still be more beneficial than thrombolytics for many individuals.)
• Coronary bypass surgery is typically used as elective surgery for patients with blocked arteries. It may be used after a heart attack if angioplasty or thrombolytics fail or are not appropriate. It is usually not performed for a few days to allow recovery of the heart muscles.

Such procedures are proving to be very important for many patients.

Angioplasty (PCI) and Coronary Stents

Percutaneous coronary intervention (PCI), also called percutaneous transluminal coronary angioplasty (PTCA) or angioplasty for short, involves opening the blocked artery. A typical angioplasty procedure has the following steps:

• The surgeon threads a narrow catheter (a tube) containing a fiber optic camera directly to the blocked vessel.
• The surgeon opens the blocked vessel using balloon angioplasty , in which a tiny deflated balloon is passed through the catheter to the vessel.
• The balloon is inflated to compress the plaque against the walls of the artery, flattening it out so that blood can once again flow through the blood vessel freely.
• To keep the artery open afterwards, surgeons use a device called a coronary stent , an expandable metal mesh tube that is implanted during angioplasty at the site of the blockage.
• Once in place, the stent pushes against the wall of the artery to keep it open. Stenting is improving results in patients with heart attack who have emergency angioplasty. It also significantly prevents reclosure and reduces heart attack rates in patients with ACS.

Experts recommend that appropriate patients receive angioplasty and stenting within 90 minutes after having a heart attack. Complications occur in about 10% of patients (about 80% within the first day). Serious side effects include heart attack and the need for additional surgery. Best results occur in hospital settings with experienced teams and backup. Women who have angioplasty after a heart attack have a higher risk of death than men. A 2005 study indicated that stents may help improve female patients’ survival.

Reclosure and Blockage During or Shortly after Angioplasty and Prevention. Reclosure of the artery often occurs during or shortly after angioplasty. A number of anticlotting drugs are used to reduce this risk. Clopidogrel (Plavix) is often given along with aspirin and thrombolytic drugs (such as abciximab) in the days before angioplasty surgery, to help prevent heart attack or stroke following surgery. Research suggests that abciximab (ReoPro) is especially helpful for patients with acute coronary syndrome.

Prevention of Restenosis. Narrowing or reclosing of the artery (restenosis) occurs within a year of angioplasty in many angioplasty patients, often requiring a repeat operation. In restenosis, the narrowing of the artery is usually due to scarring, not blood clots. Researchers are investigating whether drug-coated stents can help prevent restenosis. There have been very promising results for stents coated with sirolimus or paclitaxel. Studies suggest that these drug-coated stents may be especially important options for patients with diabetes who undergo angioplasty. Patients with diabetes are more likely to experience reclosing of the heart arteries than other patients.

Coronary Artery Bypass Graft Surgery (CABG)

Coronary artery bypass graft surgery (CABG) is the alternative elective procedure to angioplasty for opening blocked arteries in patients with severe angina, particularly those who have two or more blocked arteries. It is a very invasive procedure, however:

• The chest is opened, and the blood is rerouted through a lung-heart machine.
• The heart is stopped during the procedure.
• Segments of veins or arteries taken from elsewhere in the patient's body are fashioned into grafts , which are used to reroute the blood. The blood vessel grafts are placed in front of and beyond the blocked arteries, so the blood flows through the new vessels around the blockage.

Mortality rates with this procedure after a heart attack are much higher (6%) than when it is used electively (1 -  2%). How or when it should be used after a heart attack, then, is controversial. A 2002 study attempted to determine which patients are at highest risk for poor results from CABG after a heart attack. The study found higher risks for women, patients over age 75, and those with heart failure or other severe heart problems.

• Review Date: 4/15/2006
• Reviewed By: Harvey Simon, M.D., Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital

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