Left main intervention

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Approximately 5% of all patients undergoing coronary angiography have significant (> 50%) left main coronary artery (LMCA) stenosis. The ACC/AHA recommends coronary artery bypass grafting (CABG) in patients with significant LMCA disease who have angina and ACS. However, not all patients are operative candidates. Left main (LM) percutaneous coronary intervention (PCI) can safely and effectively treat patients in whom coronary artery bypass grafting (CABG) is suboptimal, or in patients who have had prior CABG with a ‘protected’ LMCA. ‘Protected’ left main in patients with prior CABG is defined as having at least one patent graft to the left anterior descending or circumflex artery.

Goals of Treatment

The main goal is to provide a treatment option for patients who would otherwise be poor surgical candidates, who are declined by surgery, or who refuse CABG. It is essential to properly select patients based on their anatomy who would be better candidates for drug-eluting stents (DES) vs bare metal stents (BMS) vs bifurcation stents.

Treatment Choices

Medical Therapy

Treating a patient with non-surgical methods include smoking cessation and risk factor modification. If a stent is placed, the patient is placed on prolonged dual antiplatelet therapy.

Appropriate Candidate Selection

CABG has generally been accepted as the standard of care for patients with LMCA disease. Left main intervention is considered a high risk subset of PCI, but it may be necessary for certain patients.

Candidates for LMCA PCI include:

  • Poor operative candidates
  • Low-risk patients who refuse CABG
  • Patients with 'protected' left main disease (see above)
  • Syntax score less than or equal to 22 is considered reasonable based on the Syntax trial (remains subject to debate)

High-risk features in patients with left main disease PCI include:

Hemodynamic Monitoring and Support

Hemodynamic support is not mandatory, but it should be considered for high-risk patients who have refractory angina or are awaiting CABG with persistent angina on maximal medical therapy. Options include an intra-aortic balloon pump (IABP), Impella, and Tandom Heart. Also, pulmonary artery (PA) line monitoring may be helpful.

Pre-interventional Preparation: Clearly Define Relevant Anatomy

Characterizing the patient's anatomy may reduce complications and the duration of the intervention. This can be done through several different methods:

  • Intravascular ultrasound (IVUS): The extent of the plaque, as well as any calcification, can be characterized by IVUS.
  • Multiple angiographic views: A layout of the anatomy can help characterize any disease in the LMCA ostium, the distal/bifurcation lesion, as well as the extent of the lesion.
  • Guiding catheter selection: Larger guiding catheters (i.e.: 7 or 8 French) can be used in the event that distal bifurcation intervention becomes necessary, as they provide good support and do not occlude the ostium. If necessary, side hole guiding catheters can be utilized.

In addition to characterizing the patient's anatomy, it is essential to have all stents and balloons on the table, prepped, and ready to be deployed so that no time is wasted.

Antiplatelet Regimen

Aspirin is one part of an antiplatelet regimen.

Additionally, 600 mg of Clopidogrel should be loaded, then 150 mg PO qd should be administered for one week, and then 75 mg should be given daily. Prasugrel could also be used if the patient is under age 75, over 60 kg, has no history of stroke or TIA, and is at low risk of bleeding.

GP IIb/IIIa inhibitors are typically used to prevent thrombotic closure.

Reduce Ischemic Time

Besides selecting and prepping the equipment in advance, other methods can be employed to reduce ischemic time. A rapid exchange system may be used, or the contrast in an indeflator may be diluted to allow for faster deflation. For conventional angioplasty balloon inflations, consider using a perfusion balloon in the left anterior descending artery (if this is dominant territory).

Appropriate Stent Selection

Consider using a BMS if the vessel diameter is 3.5mm or greater, and consider using a DES if the vessel diameter is small or if the lesion is long. If there is an ostial lesion, assure that the aorto-ostial region is covered by a stent.

Making a Selection

Stent Selection

There is increasing evidence for better PCI outcomes using DES instead of BMS because of lower angiographic rates of restenosis and significant reductions in major adverse events[1]. There are unclear benefits of using one DES over another based on their design (open/closed cell, modular), strut thickness/radial strength, and type of drug/polymer.

Approach Dictated by Lesion Morphology

Outcome differences have been observed according to the location of the LMCA stenosis. For instance, distal left main involvement (~75%) lesions have worse outcomes compared to more proximal lesions.

Distal bifurcation involvement has poorer results when treated with a two stent approach (i.e. kissing stents, culotte, T, etc). The approach is similar to other bifurcation therapies, but it has a higher risk with:

  • Directional coronary atherectomy (DCA) alone
  • DCA plus stenting of the principal vessel
  • Stenting of the principal vessel (which is usually the LAD) and rescuing circumflex. Bifurcation stenting (Crush, Culotte, T) have been shown to be non-inferior to each other and yield reasonable angiographic and clinical outcomes.

Calcified lesions can be treated with rotational atherectomy or stenting.

Bulky plaque can be treated with directional atherectomy and stenting, or stenting alone.

Anticipated Outcomes

An excellent angiographic result is anticipated. Once initial treatment is complete, it is important to aggressively screen for restenosis.

Other Concerns

One concern is that a left main restenosis may present as sudden death rather than recurrent angina. As restenosis is a possible complication, it is recommended to relook at the angiography generally 2-3 months post-procedure, even in the absence of symptoms so that early restenosis can be caught. Some recommend additional angiography at 6 months to identify late restenosis.

Further studies need to be done to assess the outcomes for bifurcation stenting in distal LMCA disease. In countries where it is available, implantation of an ischemia monitoring device, such as the AngelMed Guardian device[2], may permit ongoing surveillance for early detection of ischemia in these high risk patients


  1. Price MJ, Cristea E, Sawhney N; et al. (2006). "Serial angiographic follow-up of sirolimus-eluting stents for unprotected left main coronary artery revascularization". J. Am. Coll. Cardiol. 47 (4): 871–7. doi:10.1016/j.jacc.2005.12.015. PMID 16487858. Unknown parameter |month= ignored (help)
  2. Hopenfeld B, John MS, Fischell DR, Medeiros P, Guimarães HP, Piegas LS (2009). "The Guardian: an implantable system for chronic ambulatory monitoring of acute myocardial infarction". J Electrocardiol. 42 (6): 481–6. doi:10.1016/j.jelectrocard.2009.06.017. PMID 19631947.

Cost Effectiveness of Left main intervention

| group5 = Clinical Trials Involving Left main intervention | list5 = Ongoing Trials on Left main intervention at Clinical Trials.govTrial results on Left main interventionClinical Trials on Left main intervention at Google

| group6 = Guidelines / Policies / Government Resources (FDA/CDC) Regarding Left main intervention | list6 = US National Guidelines Clearinghouse on Left main interventionNICE Guidance on Left main interventionNHS PRODIGY GuidanceFDA on Left main interventionCDC on Left main intervention

| group7 = Textbook Information on Left main intervention | list7 = Books and Textbook Information on Left main intervention

| group8 = Pharmacology Resources on Left main intervention | list8 = AND (Dose)}} Dosing of Left main interventionAND (drug interactions)}} Drug interactions with Left main interventionAND (side effects)}} Side effects of Left main interventionAND (Allergy)}} Allergic reactions to Left main interventionAND (overdose)}} Overdose information on Left main interventionAND (carcinogenicity)}} Carcinogenicity information on Left main interventionAND (pregnancy)}} Left main intervention in pregnancyAND (pharmacokinetics)}} Pharmacokinetics of Left main intervention

| group9 = Genetics, Pharmacogenomics, and Proteinomics of Left main intervention | list9 = AND (pharmacogenomics)}} Genetics of Left main interventionAND (pharmacogenomics)}} Pharmacogenomics of Left main interventionAND (proteomics)}} Proteomics of Left main intervention

| group10 = Newstories on Left main intervention | list10 = Left main intervention in the newsBe alerted to news on Left main interventionNews trends on Left main intervention

| group11 = Commentary on Left main intervention | list11 = Blogs on Left main intervention

| group12 = Patient Resources on Left main intervention | list12 = Patient resources on Left main interventionDiscussion groups on Left main interventionPatient Handouts on Left main interventionDirections to Hospitals Treating Left main interventionRisk calculators and risk factors for Left main intervention

| group13 = Healthcare Provider Resources on Left main intervention | list13 = Symptoms of Left main interventionCauses & Risk Factors for Left main interventionDiagnostic studies for Left main interventionTreatment of Left main intervention

| group14 = Continuing Medical Education (CME) Programs on Left main intervention | list14 = CME Programs on Left main intervention

| group15 = International Resources on Left main intervention | list15 = Left main intervention en EspanolLeft main intervention en Francais

| group16 = Business Resources on Left main intervention | list16 = Left main intervention in the MarketplacePatents on Left main intervention

| group17 = Informatics Resources on Left main intervention | list17 = List of terms related to Left main intervention