Dave R., a 52 year-old overweight accountant, had been having chest pains occasionally for several months. The mild pain occurred during his usual weekend tennis match, and he attributed it to overeating or indigestion. The discomfort almost always diminished after the game. Recently, however, the pain seemed more severe and was lasting longer. Dave asked his physician about the problem.

The physician explained that Dave was probably experiencing angina pectoris, a symptom of coronary artery disease (CAD), and suggested that he undergo an exercise stress test. Dave walked on a treadmill, whose speed and incline were increased while he exercised. During the test, and ECG recorded continuously, and Dave's blood pressure was monitored. Near the end of the test, when Dave's heart had reached the desired rate, a small quantity of radioactive thallium-201 was injected into a vein. A scintillation counter scanned Dave's heart to determine if the blood carrying the thallium was uniformly distributed to the myocardium by branches of his coronary arteries.

The test revealed that Dave was developing CAD. In addition, he had hypertension and high blood cholesterol.

Dave was advised to stop smoking, to reduce his intake of foods high in saturated fats, cholesterol, and sodium, and to exercise regularly, rather than on weekends only. He was given medications to reduce his blood pressure and to relieve the pain of angina. Dave was also cautioned to avoid stressful situations and to lose weight.

Six months later, in spite of faithful compliance with medical advice. Dave suffered a heart attack--a sign that blood flow to part of his myocardium had been obstructed, producing oxygen deficiency (ischemia). He was a home at the time of the attack, which began as severe, crushing chest pain accompanied by shortness of breath and sweating. Paramedics stabilized Dave's condition and transported him to a hospital.

At the hospital, a cardiologist concluded from an ECG that Dave's heart attack (acute myocardial infarction) was caused by a blood clot obstructing a coronary artery (occlusive coronary thrombosis). The cardiologist intravenously administered a "clot-busting" (thrombolytic) drug, tissue plasminogen activator (t-PA).

After some time, the ECG showed that the blood vessel remained partially obstructed, so the cardiologist ordered a coronary angiogram. In this X-ray procedure, which was conducted in the cardiac catheterization laboratory, a thin plastic catheter was passed through a guiding sheath inserted into the femoral artery of Dave's right inguinal area. From there, the catheter was pushed into the aorta until it reached the region of the opening to the left coronary artery, and then near the opening to the right coronary artery.

The progress of the catheter was monitored with X-ray fluoroscopy. Each time the catheter was in proper position, a radiopaque dye (contrast medium) was released from its distal end into the blood. X-ray images that revealed the path of the dye as it entered a coronary artery and its branches were recorded on videotape and on motion picture film, which were later analyzed "frame by frame". A single severe narrowing was discovered near the origin of Dave's left anterior descending artery. The cardiologist decided to perform paercutaneous transluminal coronary agioplasty (PTCA) in order to enlarge the opening (lumen) of that vessel.

The PTCA was performed by passing another plastic catheter through the guiding sheath used for the angiogram. This second tube had a tiny deflated balloon at its tip, and when the balloon was located in the region of the arterial narrowing, it was inflated for a short time with relatively high pressure. The inflating balloon compressed the atherosclerotic plaque (atheroma), which was responsible for the obstruction, against the arterial wall. It also stretched the blood vessel wall, thus increasing the diameter of its lumen (recanalization). The blood flow to the myocardial tissue downstream from the obstruction improved immediately.

About 50% of the time, a vessel opened with PTCA becomes occluded again, because the underlying disease is still present. To prevent this restenosis, the doctor inserted a coronary stent, which is an expandable tube or coil that literally holds the vessel wall open. The cardiologist had two other options that have a slightly higher risk of causing damage. He might have vaporized the plaque obstructing the vessel with an excimer laser pulse delivered along optical fibers threaded through the catheter. Or, he could have performed atherectomy, in which a cutting device attached to the balloon inserted into the catheter spins, removing plaque that is withdrawn on the catheter tip.

Should the coronary stent fail, or an obstruction block another heart vessel, Dave might benefit from coronary bypass surgery. A portion of his internal mammary artery inside his chest wall would be removed and stitched between the aorta and the blocked coronary artery at a point beyond the obstruction.

Once again, Dave was advised to avoid saturated fats, cholesterol, and sodium in his diet, to exercise regularly, to give up smoking, to take medication to control hypertension, to reduce stress when possible, and to maintain a desirable body weight, all in the hope of retarding the progress of his coronary artery disease. Dave was also advised to undergo exercise stress tests periodically to monitor the progress of his disease.

Copyright ©1998 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use and Privacy Policy.
McGraw-Hill Higher Education is one of the many fine businesses of The McGraw-Hill Companies.
For further information about this site contact mhhe_webmaster@mcgraw-hill.com.