Left Main PCI: Why? When? How? In this ACCEL interview, Roxana Mehran, MD, FACC, is joined by Antonio Colombo, MD, FACC, to explore the appropriate use of left main PCI as a reasonable alternative to bypass surgery. Dr. Mehran: We have three big questions about the use of left main PCI: why, when and how. Let’s start with why PCI in the left main should even be considered when the gold standard is CABG? Dr. Colombo: We have to return to the history of PCI. The results were pretty bad when there was only balloon angioplasty. The emergence of stents brought an improvement. But still we had to wait for the drug-eluting stent to be applied. SYNTAX was an important trial that evaluated left main PCI, although it was not really designated for that purpose. However, in that left main subgroup the results were pretty good. I think the SYNTAX trial, even if it was not done with the best available stent, led the way to do pivotal trials to legitimate left main PCI. Are you referring to the EXCEL and NOBLE trials? Yes. EXCEL has one type of result and NOBLE has another type of result. Tell us a little bit about your idea of EXCEL vs. NOBLE and how the totality of the evidence is leading you towards PCI in the left main. NOBLE is a little bit of an outlier. Basically NOBLE evaluated the revascularization as an endpoint. And we have a little bit of an unacceptably high rate of stent thrombosis in NOBLE, maybe related to the stent or maybe to bad luck. If we put all the trials together, SYNTAX, NOBLE, EXCEL and PRECOMBAT, we end up with overall positive results. So I think left main PCI, if done in the appropriate patient and with the appropriate technique, is a reasonable alternative to bypass surgery. We have no data to say that it’s better, but we can say that it is a reasonable alternative. So, is that a Class IIa or Class I recommendation? I would still give it a Class IIa. If NOBLE was positive, I’d give it a Class I. As a Class IIa recommendation, that’s a little bit higher than may be considered. Of course, it depends. There are many features that are not taken into account. Is the left main lesion going to need two stents? Is it a bifurcation needing two stents or a very simple or relatively simple bifurcation? How much associated disease? How much disease on the left anterior descending (LAD)? Are two long stents needed on the LAD? And so forth. These nuances, partially but not completely captured by the SYNTAX score, should be taken into account. We all know each patient needs to be evaluated separately. How old is the patient? Should we subject an 86-year-old patient to bypass surgery? We didn’t have 86-yearold patients in the SYNTAX study or in the exclusion criteria. The evaluation of the patient is very important. The “why” is the great progress we’ve made in PCI and the trials that are now showing noninferiority at the very least. To me this is superiority when you don’t need a big surgical procedure. The next question is when would you undertake PCI in the left main? First, you have to prove the lesion is critical. This is not so easy because very frequently the left main lesion has associated disease of the LAD. So, using fractional flow reserve (FFR) is not always appropriate, because it becomes unreliable if there are downstream lesions. FFR can be used if the lesion is not clearly critical. IVUS can be used if the lesion is intermediate. If the lesion is critical in a very clear fashion, it’s just obvious of course and you don’t have to use anything. Symptoms can be subtle for left main stenosis. There isn’t always angina. Sometimes there’s shortness of breath and fatigue but the heart function is not normal. So angina may not be the only symptom the patient reports. We need a full picture. Lastly, the most important question is how do we perform PCI in the left main? You’re a master operator. How do you prepare? In the old times, we always had to use a femoral approach. This was because we thought of this as a serious condition and we needed to put ourselves in the best possible situation. Nowadays we can perform most left main PCIs with a radial approach. A large guiding catheter isn’t needed and a six French guiding catheter is sufficient. The next question is whether we need a more dynamic support. Most of the time it isn’t needed. Of course, if we’re dealing with a very calcified left main, where the ejection fraction is not ideal, then we may consider a more dynamic support, up to the balloon pump or even the Impella. For a complex left main PCI, we must ask the surgeon why we should do it instead of surgery. If the patient is 89 years old, we must take the risk to go to a complex left main PCI. If the patient is 68 years old, maybe we need to evaluate surgical options. Regarding technique, first of all, we have to take advantage of the size. The left main is 3.5 millimeters or bigger in most patients. If there’s any doubt that the left main looks smaller, do IVUS and reconsider the vessel size. Many times, angiography underestimates the vessel size. If you can implant a 3.5 and not a 3.0 stent, it’s a big advantage for a number of reasons. Second, always privilege if possible a one-stent-approach. I say if possible because we don’t have to always implant one stent. If the bifurcation is complex, utilize two stents, even as the intention to treat. It’s not making a mistake to implant two stents if needed. We’re making a mistake to implant two stents if they’re not needed. And if implanting two stents, be absolutely diligent on the technique. Of course, even with one stent, but with two stents we must be more diligent. We do IVUS 80 percent of the time, maybe even 100 percent. But with two stents, IVUS is a must. We must be absolutely sure all the metal is embedded in the wall of the artery, no protrusion in the lumen, and we’ve achieved the maximum possible minimal lumen area in the LAD and towards the circumflex. Do you bring patients back for a routine angiographic follow-up or wait for symptoms? Noninvasive follow-up is important because sometimes the symptoms don’t show up. I don’t think routine angiographic follow-up is necessary. Lastly, let’s talk about potent P2Y12 inhibitors in these patients. Do you trust clopidogrel alone or do you feel that it should be more potent? I think if you have done a good implant, unless you have multiple stents in other vessels, long stents in the LAD, standard clopidogrel and aspirin should be sufficient. Left main is a big vessel, the flow is very high, so at least theoretically the risk of thrombosis should be low. This interview has been edited for print from a transcript.
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