Coronary angiography

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 1-2% 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 5% 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.
  

Coronary artery stents

Coronary artery stents are small hollow cylinders that can be deployed over the angioplasty balloons and left within the coronary arteries to keep the arteries open. Stents help prevent abrupt closure of arteries shortly after PTCA . They also prevent restenosis (recurrent narrowing of the arteries) several months after PTCA.