What is the Left Main Coronary Artery?
The left side of the heart is normally supplied with blood flow from two coronary arteries, the left anterior descending (LAD) and the left circumflex (LCx). These two vessels are branches of the left main (LM). Blockage of the LM causes decreased blood flow to a large portion of heart muscle. If acute, as with a heart attack, this blockage is extremely dangerous.
How Common is Blockage of the Left Main?
About 6% of patients with coronary artery disease have a significant blockage of the LM.
What is the Prognosis of Left Main Blockage?
The prognosis of significant blockage in the LM is poor. Three-year survival can be as low as 37%.
What is the Best Treatment for Left Main Blockage?
Medication alone is inadequate to treat blockage of the LM. Bypass surgery is superior to medications and improves survival in those with cardiac symptoms who are at high risk of developing a heart attack.
Balloon dilation without stenting of the LM is not recommended. The complications and risk of the vessel closing rapidly closing are high.
Balloon and stenting with a bare metal stent also places patients at risk of the LM closing after the procedure. Drug coated, or drug-eluting stents, are a new development in cardiac technology. These stents may allow for the balloon and stent procedure to successfully repair left main blockages.
Coronary bypass surgery is accepted as the best way to treat blockages of the left main. Nevertheless, surgery has significant risks. The chance of dying during the procedure ranges from 1% to 4%. Additionally, a prolonged recovery time of weeks to months is common.
When Else is Bypass Better?
If blockage is present in several coronary arteries, bypass surgery may offer an advantage over the balloon and stent procedure. It is not clear if this advantage applies when surgery is compared to drug-eluting stents.
Will Drug Eluting Stents Make it Easier to Fix the Left Main?
Drug-eluting stents decrease the chance of stent closure (restenosis). They, however, increase the chance of clotting inside the stent (late thrombosis). Those who receive drug-eluting stents require long-term use of aspirin and Plavix to prevent clotting. These medicines unfortunately increase the risk of bleeding and make non-cardiac surgery more dangerous. Because stent thrombosis in the LM would be catastrophic, aspirin and Plavix are likely needed for life if a balloon and stent procedure is done here.
Current medical findigs suggest that the balloon and stent procedure may be an alternative to bypass surgery for some patients. A discussion between you, a cardiologist, and a heart surgeon is critical prior to making this decision.
Sources:
Taggart DP, Kaul S, Boden WE, et al. Revascularization for Unprotected Left Main Stem Coronary Artery Stenosis. J Am Coll Cardiol 2008;51:885-92.
Brinker J. The Left Main Facts: Faced, Spun, But Alas Too Few. J Am Coll Cardiol 2008;51:893-8.