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Where next for PCI versus CABG?

Cardiovascular Surgery
Interventional Cardiology and Cardiovascular Surgery

Saturday and Sunday saw a host of Late-Breaking Science trials that provided further insights into the safety and efficacy of contemporary percutaneous coronary intervention (PCI). For example, on Saturday, results of the SYNTAX II study showed that state-of-the-art PCI yields fewer adverse events in de novo three-vessel disease. However, the question remains—when should PCI be used and when should surgery be preferred? Professor Michael Haude (Medical Clinic I Lukas Hospital, Neuss, Germany) explores recent evidence regarding the use of of PCI versus coronary artery bypass grafting (CABG) for coronary revascularisation. 

SYNTAX II is a European multicentre single-arm study that compared outcomes of patients (450) with de novo three-vessel disease undergoing PCI with contemporary techniques (such as next-generation drug-eluting stents) with patients who underwent PCI in the first SYNTAX trial. This trial, which compared PCI with a first-generation drug-eluting stent with CABG, found that the more disease present, the greater the benefit of surgery (versus PCI). However, it also showed that left main PCI was associated with similar outcomes to those of surgery. 

Following SYNTAX, the EXCEL study found that left main PCI was associated with a similar rate of death, stroke, and myocardial infarction as was surgery at three years. However, another study that was published at the same time as EXCEL— NOBLE—found that PCI was associated with a significantly higher rate of major adverse cardiac and cerebrovascular events at five years compared with CABG. According to Prof. Haude, these apparently opposing results are not as conflicting as they may seem and both support the findings of the original SYNTAX study. He says: “If you have single-vessel left main disease, or limited additional disease, the results between surgery and PCI are equivalent. And, the more distal disease you have to the left main, the more favourable it is to surgery. NOBLE and EXCEL didn’t change that; it was already known from a subgroup analysis of SYNTAX.”

Furthermore, he notes that—compared with CABG—repeat revascularisation is the “Achilles heel” of PCI, stating: There is no difference in cardiovascular mortality or myocardial infarction between PCI and CABG. But when you include revascularisation among the endpoints, we always have more reinterventions with PCI.”

Subgroup analyses of PCI versus CABG trials, including SYNTAX, demonstrate that complete revascularisation PCI (both culprit and non-culprit vessels), in the acute setting, has similar rates of revascularisation to surgery in what Prof. Haude calls a reasonable timeframe, which means two years”. But, he adds: “We need to see what is going to be happening in five and 10 years to find out whether outcomes with PCI are still as good as they are for CABG.”

Also, with PCI, revascularisation may occur because further stenoses can develop in the vessel that has been treated. But, as most of the arterial bed is being bypassed, CABG does not have this issue. “PCI is only treating the tip of the iceberg. Therefore, challenging CABG outcomes in the long term will be extremely difficult. PCI is only treating the emerging stenosis but not the underlying complete atherosclerotic process in the arterial wall especially outside of the stented vessel segment,” he observes. Additionally, the durability of the—nowadays more frequently used—arterial grafts is another factor in favour of CABG.

However, since the original SYNTAX trial, developments in PCI technology—such as next-generation drug-eluting stents that have thinner struts and more flexibility—have enabled lesions that previously would have been too complex for PCI to come within its scope. Also, the SYNTAX score II has optimised decision-making between CABG and PCI. Unlike the anatomical SYNTAX score, it is based on clinical characteristics as well as anatomical characteristics. Looking to the future, Prof. Haude says that bioresorbable scaffolds still have the potential to improve on existing devices and even possibly be equivalent to surgery. He comments: “There is still hope with the improved technology of the second-generation devices [there have been some limitations with the first-generation devices]. But, these newer devices have to be compared in randomised controlled trials against current drug-eluting stents to show that they, at least, are non-inferior to those devices before they can be evaluated against CABG.” 

Prof. Haude is Chairperson, alongside Doctor Marie-Claude Morice (Institut Cardiovasculaire Paris Sud, Paris, France), at today’s 40 years of percutaneous coronary interventions and beyond (16:30–18:00; Bishkek - Village 6). 

Click here to read other scientific highlights in the full edition of the Congress news.