Heart Attack and Acute Coronary Syndrome

Description

Alternative Names

Surgery

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

• Emergency angioplasty is the standard procedure for heart attack patients and more effective than the use of thrombolytic agents 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.

Click the icon to see an illustrated series detailing a heart bypass surgery.

Angioplasty (PTCA) and Coronary Stents

Percutaneous transluminal coronary angioplasty (PTCA), usually simply called angioplasty, involves opening the blocked artery. A typical angioplasty procedure follows the following steps:

Click the icon to see an image of an angioplasty.

• The surgeon threads a narrow catheter (a tube) containing a fiber optic camera directly to the blocked vessel.
• The physician opens the blocked vessel using balloon angioplasty, in which the surgeon passes a tiny deflated balloon 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.
• In order to keep the artery open afterwards, surgeons now most often employ a device called a coronary stent, which is an expandable metal mesh tube that is implanted during angioplasty at the site of the blockage. (Stents are being investigated as the initial opening device instead of balloon angioplasty, but benefits are not clear.)
• Once in place, the stent pushes against the wall of the artery to keep it open. Stenting is improving outcome in patients with heart attack who have emergency angioplasty. It also significantly prevents reclosure and reduces heart attack rates in patients with ACS. A 2002 study reported that their safety and effectiveness was sustained for seven to 11 years.

Complications occur in about 10% of patients (about 80% within the first day). Serious ones include heart attack and the need for additional surgery. Outcomes are best in hospital settings with experienced teams and backup. According to a 2003 study, outcomes are also better if the procedure is done during routine working hours. It is not know if sleep deprivation in the medical professionals or increased clotting factors during the night are responsible for these differences.

Reclosure and Blockage During or Shortly after Angioplasty and Prevention. Reclosure of the artery during or shortly after angioplasty often occurs. A number of anti-clotting agents are used to help prevent this, although they are not wholly protective because reclosure in some cases is due to other, unknown causes.

Prevention of Restenosis. Narrowing or reclosing of the artery (restenosis) occurs within a year of angioplasty in a large minority of angioplasty patients, often requiring a repeat operation. The narrowing of the artery in this case is not due to blood clots and so anti-clotting agents are not useful. Of great interest and promise are studies that show no restenosis in patients who have received stents that were coated with the drug sirolimus. [For more information, see the Well-Connected Report #3 Coronary Artery Disease and Angina.]

Click the icon to see an illustrated series detailing balloon angioplasty.

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% to 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 a poor outcome from CABG after a heart attack. They included women, patients over 75, those with heart failure or other severe heart problems.