Ask Dr. K: Heart surgery depends on many factors

DEAR DOCTOR K: When a patient has one or more blocked coronary arteries, how does a doctor decide whether to perform an angioplasty or bypass surgery?

DEAR READER: The heart gets its blood supply from coronary arteries. These arteries can get clogged by cholesterol-filled plaques of atherosclerosis, causing a permanent obstruction.

Such a permanent obstruction can cause symptoms such as pain (the condition called angina), or a weaker heartbeat when the heart is forced to work harder than normal. The heart works harder during exercise and during times when people get angry or their blood pressure is high (for example, because they are not taking their blood pressure medication).

Medicines can help reduce the work of the heart. An aggressively healthy lifestyle, over many months, can shrink the size of the obstructing plaques. However, sometimes a permanent obstruction from a plaque needs to be eliminated promptly. The two main treatments are angioplasty plus stenting, or coronary artery bypass graft surgery.

Angioplasty plus stenting: A small balloon wrapped in a collapsed stent is inserted into a blood vessel in the groin or arm and maneuvered into the heart. When the balloon is inflated, it flattens the cholesterol-filled plaque that was restricting blood flow. The balloon is deflated and removed. The stent remains behind to prop open the artery.

CABG: During open-heart surgery, an artery or vein taken from elsewhere in the body is stitched in place to reroute blood around the blocked artery.

When all three of the heart’s coronary arteries are narrowed or blocked, bypass is the better choice.

When fewer than three coronary arteries are affected, the choice depends on which arteries are involved. The left anterior descending artery feeds blood to more of the heart muscle than the other two coronary arteries. When the LAD is narrowed or blocked, bypass surgery usually is best.