Left main intervention
Percutaneous coronary intervention Microchapters
Recommendations for Perioperative Management–Timing of Elective Noncardiac Surgery in Patients Treated With PCI and DAPT
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. ; Associate Editors-In-Chief: Neil M. Gheewala, M.D.
Left Main Intervention
The left main coronary artery provides blood flow to two of the main coronary arteries (the left anterior descending artery as well as the circumflex coronary artery), and approximately 5% of all patients undergoing coronary angiography have significant (> 50%) left main coronary artery (LMCA) stenosis. Assessment of the left main is associated with the greatest amount of inter and intraobserver variability in angiography. The left main is short, and is often diseased with asymmetric lesions making its assessment on angiography difficult. There may be diffuse disease which may cause an underestimation of the extent of involvement on angiography. While luminal encroachment is defined as a minimum lumen area less than 4 mm² in the epicardial arteries, a minimum lumen area less than 6 mm² in the left main is considered to be significant. A minimum lumen area less than 6 mm² in the left main corresponds with a fractional flow reserve less than 0.75. A minimum lumen area less than 6 mm² also corresponds to a minimum lumen area less than 4 mm² in either the LAD or the circumflex arteries. In interrogating ostial lesions, it is critical to disengage the guide so that the guide is not mistaken for the lumen of the artery.
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) 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. 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 as to whether they are optimal candidates for drug-eluting stents (DES) vs bare metal stents (BMS) vs bifurcation stents.
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:
- Absence of internal mammary artery, radial artery, or saphenous vein grafts distally leading to an ‘unprotected’ left main.
- Concomitant right coronary artery (RCA) disease and/or lack of collaterals from RCA
- Left ventricular dysfunction
Technical Aspects of Performing PCI in the Left Main
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.
- A pre-PCI loading dose of non-enteric coated Aspirin is essential.
- A pre-PCI loading dose of 600 mg of Clopidogrel should be administered, then 150 mg PO qd should be administered for one week, and then 75 mg should be given daily for the rest of the patient's life. Prasugrel could alternatively be administered if the patient is under age 75, over 60 kg, has no history of stroke or TIA, and is at low risk of bleeding. Patients should be told not to discontinue their thienopyridine unless they have spoken with their cardiologist.
- 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
- The contrast in the deflator should be diluted with saline to allow for faster deflation.
- For conventional angioplasty balloon inflations, a perfusion balloon can be utilized in the left anterior descending artery (if this is the dominant territory).
Appropriate Stent Selection
Consider using a BMS if the left main diameter is 3.5 mm or greater, and consider using a DES if the left main diameter is small or if the lesion is long. If there is an ostial lesion, the operator should assure that the aorto-ostial region is covered by a stent.
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. 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.
Exercise Tolerance Test Screening
There is a consensus opinion that it is important to aggressively screen for restenosis. Left main restenosis may unfortunately present as sudden cardiac death rather than recurrent angina. It is therefore recommended that repeat angiography be performed 2-3 months following the procedure, even in the absence of symptoms. Some operators also recommend additional angiography at 6 months to identify late restenosis.
Use of and Indwelling EKG Electrode and Alarming Device
In countries where it is available, implantation of an ischemia monitoring device, such as the AngelMed Guardian device, may permit ongoing surveillance for early detection of ischemia in these high risk patients.
Risk Factor Modification
Treating a patient with non-surgical methods include smoking cessation and cardiac risk factor modification.
Dual Antiplatelet Therapy
If a stent is placed, the patient should placed on prolonged dual antiplatelet therapy. Either clopidogrel or Prasugrel for the rest of the patient's life are suitable choices.
2011 ACCF/AHA/SCAI Guidelines for Percutaneous Coronary Intervention (DO NOT EDIT)
Revascularization to Improve Survival in Left Main Coronary Artery Disease (DO NOT EDIT)
|"1. CABG to improve survival is recommended for patients with significant (≥50% diameter stenosis) left main coronary artery stenosis. (Level of Evidence: B)"|
|Class III (Harm)|
"1. PCI to improve survival should not be performed in stable patients with significant (greater than or equal to 50% diameter stenosis) unprotected left main CAD who have unfavorable anatomy for PCI and who are good candidates for CABG.  (Level of Evidence: B)"
"1. PCI to improve survival is reasonable as an alternative to CABG in selected stable patients with significant (greater than or equal to 50% diameter stenosis) unprotected left main CAD with:
"2. PCI to improve survival is reasonable in patients with UA/NSTEMI when an unprotected left main coronary artery is the culprit lesion and the patient is not a candidate for CABG.  (Level of Evidence: B)"
"3. PCI to improve survival is reasonable in patients with acute STEMI when an unprotected left main coronary artery is the culprit lesion, distal coronary flow is less than TIMI (Thrombolysis In Myocardial Infarction) grade 3, and PCI can be performed more rapidly and safely than CABG.  (Level of Evidence: C)"
"1. PCI to improve survival may be reasonable as an alternative to CABG in selected stable patients with significant (greater than or equal to 50% diameter stenosis) unprotected left main CAD with:
- ↑ 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
- ↑ 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.
- ↑ 3.0 3.1 Levine GN, Bates ER, Blankenship JC, Bailey SR, Bittl JA, Cercek B, Chambers CE, Ellis SG, Guyton RA, Hollenberg SM, Khot UN, Lange RA, Mauri L, Mehran R, Moussa ID, Mukherjee D, Nallamothu BK, Ting HH (2011). "2011 ACCF/AHA/SCAI Guideline for Percutaneous Coronary Intervention: Executive Summary A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Society for Cardiovascular Angiography and Interventions" (PDF). Journal of the American College of Cardiology. 58 (24): 2550–83. doi:10.1016/j.jacc.2011.08.006. PMID 22070837. Retrieved 2011-12-08. Text "PDF" ignored (help); Unknown parameter
- ↑ 4.0 4.1 4.2 Chakravarty T, Buch MH, Naik H, White AJ, Doctor N, Schapira J et al. (2011)Predictive accuracy of SYNTAX score for predicting long-term outcomes of unprotected left main coronary artery revascularization. Am J Cardiol 107 (3):360-6. DOI:10.1016/j.amjcard.2010.09.029 PMID:21256999
- ↑ 5.0 5.1 5.2 Kim YH, Park DW, Kim WJ, Lee JY, Yun SC, Kang SJ et al. (2010) Validation of SYNTAX (Synergy between PCI with Taxus and Cardiac Surgery) score for prediction of outcomes after unprotected left main coronary revascularization. JACC Cardiovasc Interv 3 (6):612-23.DOI:10.1016/j.jcin.2010.04.004 PMID:20630454
- ↑ 6.0 6.1 6.2 6.3 Morice MC, Serruys PW, Kappetein AP, Feldman TE, Ståhle E, Colombo A et al. (2010)Outcomes in patients with de novo left main disease treated with either percutaneous coronary intervention using paclitaxel-eluting stents or coronary artery bypass graft treatment in the Synergy Between Percutaneous Coronary Intervention with TAXUS and Cardiac Surgery (SYNTAX) trial. Circulation 121 (24):2645-53.DOI:10.1161/CIRCULATIONAHA.109.899211 PMID:20530001
- ↑ Caracciolo EA, Davis KB, Sopko G, Kaiser GC, Corley SD, Schaff H et al. (1995) Comparison of surgical and medical group survival in patients with left main coronary artery disease. Long-term CASS experience. Circulation 91 (9):2325-34. PMID: 7729018
- ↑ Chaitman BR, Fisher LD, Bourassa MG, Davis K, Rogers WJ, Maynard C et al. (1981)Effect of coronary bypass surgery on survival patterns in subsets of patients with left main coronary artery disease. Report of the Collaborative Study in Coronary Artery Surgery (CASS). Am J Cardiol 48 (4):765-77. PMID:7025604
- ↑ Dzavik V, Ghali WA, Norris C, Mitchell LB, Koshal A, Saunders LD et al. (2001)Long-term survival in 11,661 patients with multivessel coronary artery disease in the era of stenting: a report from the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH) Investigators. Am Heart J142 (1):119-26. DOI:10.1067/mhj.2001.116072 PMID:11431667
- ↑ Takaro T, Hultgren HN, Lipton MJ, Detre KM (1976) The VA cooperative randomized study of surgery for coronary arterial occlusive disease II. Subgroup with significant left main lesions.Circulation 54 (6 Suppl):III107-17. PMID: 791537
- ↑ Takaro T, Peduzzi P, Detre KM, Hultgren HN, Murphy ML, van der Bel-Kahn J et al. (1982) Survival in subgroups of patients with left main coronary artery disease. Veterans Administration Cooperative Study of Surgery for Coronary Arterial Occlusive Disease. Circulation 66 (1):14-22. PMID: 
- ↑ Taylor HA, Deumite NJ, Chaitman BR, Davis KB, Killip T, Rogers WJ (1989) Asymptomatic left main coronary artery disease in the Coronary Artery Surgery Study (CASS) registry. Circulation 79 (6):1171-9. PMID:2785870
- ↑ Yusuf S, Zucker D, Peduzzi P, Fisher LD, Takaro T, Kennedy JW et al. (1994) Effect of coronary artery bypass graft surgery on survival: overview of 10-year results from randomised trials by the Coronary Artery Bypass Graft Surgery Trialists Collaboration. Lancet 344 (8922):563-70. PMID: 
- ↑ 14.0 14.1 Kappetein AP, Feldman TE, Mack MJ, Morice MC, Holmes DR, Ståhle E et al. (2011)Comparison of coronary bypass surgery with drug-eluting stenting for the treatment of left main and/or three-vessel disease: 3-year follow-up of the SYNTAX trial. Eur Heart J 32 (17):2125-34.  PMID: 21697170
- ↑ 15.0 15.1 Capodanno D, Caggegi A, Miano M, Cincotta G, Dipasqua F, Giacchi G et al. (2011)Global risk classification and clinical SYNTAX (synergy between percutaneous coronary intervention with TAXUS and cardiac surgery) score in patients undergoing percutaneous or surgical left main revascularization. JACC Cardiovasc Interv 4 (3):287-97. DOI:10.1016/j.jcin.2010.10.013PMID: 21435606
- ↑ 16.0 16.1 Hannan EL, Wu C, Walford G, Culliford AT, Gold JP, Smith CR et al. (2008)Drug-eluting stents vs. coronary-artery bypass grafting in multivessel coronary disease. N Engl J Med 358 (4):331-41.DOI:10.1056/NEJMoa071804 PMID: 
- ↑ 17.0 17.1 17.2 Ellis SG, Tamai H, Nobuyoshi M, Kosuga K, Colombo A, Holmes DR et al. (1997) Contemporary percutaneous treatment of unprotected left main coronary stenoses: initial results from a multicenter registry analysis 1994-1996.Circulation 96 (11):3867-72. PMID: 9403609
- ↑ 18.0 18.1 Biondi-Zoccai GG, Lotrionte M, Moretti C, Meliga E, Agostoni P, Valgimigli M et al. (2008) A collaborative systematic review and meta-analysis on 1278 patients undergoing percutaneous drug-eluting stenting for unprotected left main coronary artery disease. Am Heart J 155 (2):274-83.DOI:10.1016/j.ahj.2007.10.009 PMID:18215597
- ↑ 19.0 19.1 Boudriot E, Thiele H, Walther T, Liebetrau C, Boeckstegers P, Pohl T et al. (2011)Randomized comparison of percutaneous coronary intervention with sirolimus-eluting stents versus coronary artery bypass grafting in unprotected left main stem stenosis. J Am Coll Cardiol 57 (5):538-45.DOI:10.1016/j.jacc.2010.09.038 PMID:21272743
- ↑ 20.0 20.1 20.2 Brener SJ, Galla JM, Bryant R, Sabik JF, Ellis SG (2008) Comparison of percutaneous versus surgical revascularization of severe unprotected left main coronary stenosis in matched patients. Am J Cardiol 101 (2):169-72.  PMID: 18178401
- ↑ 21.0 21.1 Buszman PE, Kiesz SR, Bochenek A, Peszek-Przybyla E, Szkrobka I, Debinski M et al. (2008) Acute and late outcomes of unprotected left main stenting in comparison with surgical revascularization. J Am Coll Cardiol 51 (5):538-45.DOI:10.1016/j.jacc.2007.09.054 PMID:18237682
- ↑ 22.0 22.1 22.2 Chieffo A, Morici N, Maisano F, Bonizzoni E, Cosgrave J, Montorfano M et al. (2006)Percutaneous treatment with drug-eluting stent implantation versus bypass surgery for unprotected left main stenosis: a single-center experience.Circulation 113 (21):2542-7.  PMID: 16717151
- ↑ 23.0 23.1 23.2 Lee MS, Kapoor N, Jamal F, Czer L, Aragon J, Forrester J et al. (2006)Comparison of coronary artery bypass surgery with percutaneous coronary intervention with drug-eluting stents for unprotected left main coronary artery disease. J Am Coll Cardiol 47 (4):864-70.  PMID: 16487857
- ↑ 24.0 24.1 Mäkikallio TH, Niemelä M, Kervinen K, Jokinen V, Laukkanen J, Ylitalo I et al. (2008) Coronary angioplasty in drug eluting stent era for the treatment of unprotected left main stenosis compared to coronary artery bypass grafting. Ann Med 40 (6):437-43. DOI:10.1080/07853890701879790PMID: 18608116
- ↑ 25.0 25.1 Naik H, White AJ, Chakravarty T, Forrester J, Fontana G, Kar S et al. (2009)A meta-analysis of 3,773 patients treated with percutaneous coronary intervention or surgery for unprotected left main coronary artery stenosis.JACC Cardiovasc Interv 2 (8):739-47.  PMID: 19695542
- ↑ 26.0 26.1 Palmerini T, Marzocchi A, Marrozzini C, Ortolani P, Saia F, Savini C et al. (2006) Comparison between coronary angioplasty and coronary artery bypass surgery for the treatment of unprotected left main coronary artery stenosis (the Bologna Registry). Am J Cardiol 98 (1):54-9.DOI:10.1016/j.amjcard.2006.01.070 PMID:16784920
- ↑ 27.0 27.1 Park DW, Seung KB, Kim YH, Lee JY, Kim WJ, Kang SJ et al. (2010) Long-term safety and efficacy of stenting versus coronary artery bypass grafting for unprotected left main coronary artery disease: 5-year results from the MAIN-COMPARE (Revascularization for Unprotected Left Main Coronary Artery Stenosis: Comparison of Percutaneous Coronary Angioplasty Versus Surgical Revascularization) registry. J Am Coll Cardiol 56 (2):117-24.  PMID: 20451344
- ↑ 28.0 28.1 28.2 Rodés-Cabau J, Deblois J, Bertrand OF, Mohammadi S, Courtis J, Larose E et al. (2008) Nonrandomized comparison of coronary artery bypass surgery and percutaneous coronary intervention for the treatment of unprotected left main coronary artery disease in octogenarians. Circulation 118 (23):2374-81.DOI:10.1161/CIRCULATIONAHA.107.727099 PMID:19029471
- ↑ 29.0 29.1 29.2 Sanmartín M, Baz JA, Claro R, Asorey V, Durán D, Pradas G et al. (2007) Comparison of drug-eluting stents versus surgery for unprotected left main coronary artery disease. Am J Cardiol 100 (6):970-3.DOI:10.1016/j.amjcard.2007.04.037 PMID:17826380
- ↑ 30.0 30.1 30.2 Seung KB, Park DW, Kim YH, Lee SW, Lee CW, Hong MK et al. (2008) Stents versus coronary-artery bypass grafting for left main coronary artery disease. N Engl J Med 358 (17):1781-92.DOI:10.1056/NEJMoa0801441 PMID:18378517
- ↑ 31.0 31.1 31.2 White AJ, Kedia G, Mirocha JM, Lee MS, Forrester JS, Morales WC et al. (2008)Comparison of coronary artery bypass surgery and percutaneous drug-eluting stent implantation for treatment of left main coronary artery stenosis.JACC Cardiovasc Interv 1 (3):236-45.  PMID: 19463306
- ↑ Chieffo A, Magni V, Latib A, Maisano F, Ielasi A, Montorfano M et al. (2010)5-year outcomes following percutaneous coronary intervention with drug-eluting stent implantation versus coronary artery bypass graft for unprotected left main coronary artery lesions the Milan experience. JACC Cardiovasc Interv 3 (6):595-601. DOI:10.1016/j.jcin.2010.03.014 PMID:20630452
- ↑ Montalescot G, Brieger D, Eagle KA, Anderson FA, FitzGerald G, Lee MS et al. (2009) Unprotected left main revascularization in patients with acute coronary syndromes. Eur Heart J 30 (19):2308-17.DOI:10.1093/eurheartj/ehp353 PMID:19720640
- ↑ Lee MS, Tseng CH, Barker CM, Menon V, Steckman D, Shemin R et al. (2008)Outcome after surgery and percutaneous intervention for cardiogenic shock and left main disease. Ann Thorac Surg 86 (1):29-34.DOI:10.1016/j.athoracsur.2008.03.019 PMID:18573394
- ↑ Lee MS, Bokhoor P, Park SJ, Kim YH, Stone GW, Sheiban I et al. (2010) Unprotected left main coronary disease and ST-segment elevation myocardial infarction: a contemporary review and argument for percutaneous coronary intervention. JACC Cardiovasc Interv 3 (8):791-5.DOI:10.1016/j.jcin.2010.06.005 PMID:20723848
- ↑ Park SJ, Kim YH, Park DW, Yun SC, Ahn JM, Song HG et al. (2011)Randomized trial of stents versus bypass surgery for left main coronary artery disease. N Engl J Med 364 (18):1718-27.DOI:10.1056/NEJMoa1100452 PMID: