Practice Update: Cardiology

MY APPROACH 22

My approach to the patient with left main disease By Eric R Bates MD Dr Bates, Professor of Internal Medicine

at the University of Michigan, discusses his approach to the management of patients with unprotected left main coronary artery disease.

C oronary artery bypass graft surgery (CABG) has historically been recommended over percuta- neous coronary artery intervention (PCI) as the preferred revascularization strategy for patients with significant unprotected left main coronary artery dis- ease (CAD). However, PCI has more recently become a treatment option in selected patients with left main CAD who do not have extensive or complex CAD in the other coronary arteries. When equipoise is pres- ent, the 30-day rates for death, myocardial infarction (MI), and stroke will be lower with PCI, and CABG will have a higher risk for bleeding and infection and longer hospital and recovery times. However, the long-term risks for death, spontaneous MI, and repeat revas- cularization will be lower with CABG due to more complete revascularization in some patients and the survival advantage of the left internal mammary artery bypass graft. Nevertheless, because most patients have no adverse cardiac events after PCI or CABG, PCI is becoming a more popular revascularization option than in earlier treatment eras. The majority of patients with unprotected left main CAD will have multivessel CAD where CABG will often be preferred. Lesion location, length, and morphology are important variables in selecting possible PCI can- didates. It is not clear that intravascular ultrasound or fractional flow reserve measurements add to risk strati- fication, which has always been made on angiographic anatomic considerations. Stent implantation in an ostial or body stenosis is more straightforward than treating a distal bifurcation or trifurcation stenosis where reste- nosis rates are higher. Minimum and reference lumen diameters and the distal bifurcation angle have tech- nical implications. Discrete lesions are easier to treat

with PCI than diffuse or calcified lesions. In the pres- ent era of excellent primary and secondary prevention for CAD, revascularization of a 50% to 70% stenosis may not have the same clinical imperative as a more severe stenosis. Whereas clinical comorbidities have little impact on PCI results, they do predict increased risk for surgery, which may be considered excessive in some patients when PCI is an option. These are my clinical impressions: • PCI is a good treatment option for those with con- traindications to CABG, if it is technically reasonable. • If a discrete ostial or body left main stenosis is present with or without one-vessel CAD, PCI with stent implantation may be the best option. • If a distal left main stenosis only involves the ostium of either the left anterior descending (LAD) or left circumflex (LCX) artery, but not both, the stenosis can be treated with the cross-over (one-stent) technique if the bifurcation angle is wide enough to make it unlikely that plaque will be shifted into the uninvolved artery during stent deployment. • If bifurcation disease extends into both the LAD and LCX and would require the two-stent technique, or if three-vessel CAD is present, CABG may be the best option. • PCI candidates need to be able to take dual anti- platelet therapy for at least 6 to 12 months because of the devastating complications with stent throm- bosis in this location. Individual decisions about revascularization should be made by the local heart team and the patient after consideration of possible benefits and risks and the patient’s comorbidities, circumstances, and wishes.

PRACTICEUPDATE CARDIOLOGY