麻豆传媒

Neither sex nor involvement of a distal bifurcation gave either percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) an advantage in the revascularization of left main coronary artery disease, two EXCEL substudies found, although a Korean registry study suggested that some PCI strategies work better than others for left main bifurcation lesions.

EXCEL was an international trial that randomized 1,905 patients with low and intermediate SYNTAX scores with left main disease to PCI or CABG. The trialists previously reported similar rates between the two arms in the composite primary endpoint of death, myocardial infarction (MI), and stroke at 3 years.

Site of the Left Main Lesion

Again, there was no difference in event rates between groups even when the researchers considered the lesion site, according to a pre-specified substudy of EXCEL published in the July 9 issue of .

Specifically, the primary endpoint was just as likely whether patients had left main coronary lesions as isolated ostial/shaft disease (12.4% versus 13.5%, OR 0.90, 95% CI 0.45 to 1.81) or with distal bifurcation involvement (15.6% for PCI versus 14.9% for CABG, OR 1.08, 95% CI 0.81 to 1.42), reported Anthony Gershlick, MBBS, of University Hospitals of Leicester, England, and colleagues.

"The favorable outcome in terms of major cardiovascular events in the EXCEL trial with PCI for treatment of distal left main bifurcation disease is particularly notable given that the mean SYNTAX score in the distal left main bifurcation group was 28 (compared with 20 in patients with isolated left main ostial/shaft disease), and that 41% of the PCI-assigned distal bifurcation group had trifurcation disease," the authors noted.

Even so, ischemia-driven revascularization occurred more frequently in the 3 years after PCI than after CABG in patients with left main distal bifurcation disease (13.0% versus 7.2%, OR 2.00, 95% C 1.41 to 2.85). Patients with disease only at the left main ostium or shaft shared similar rates of this endpoint after PCI and surgery (9.7% versus 8.4%, OR 1.18, 95% CI 0.52 to 2.69).

The Impact of Sex

In a in the same issue of the journal, sex was no predictor of either the primary endpoint or all-cause death at 3 years.

The composite endpoint occurred in 19.7% of women getting PCI, 14.6% of women getting CABG, 13.8% of men getting PCI, and 14.7% of men getting CABG (P=0.06 for interaction). The differences were mainly driven by a higher periprocedural rate of MI in women receiving stenting and men getting surgery, according to a group led by Patrick Serruys, MD, PhD, of Erasmus University in the Netherlands.

Only chronic obstructive pulmonary disease and diabetes turned out to be independent predictors of combined death, MI, and stroke.

"In patients with unprotected left main disease in the EXCEL trial, sex was not an independent predictor of adverse outcomes after revascularization," Serruys and colleagues noted. "However, women undergoing PCI had a trend toward worse outcomes, a finding related to associated comorbidities and increased periprocedural complications. Further studies are required to determine the optimal revascularization modality in women with complex coronary artery disease."

The EXCEL population was 76.9% men. Women were older and were more likely to have hypertension, hyperlipidemia, and diabetes, although a lower coronary anatomic burden and complexity (mean SYNTAX score 24.2 versus 27.2, P<0.001). Men had more bifurcation lesions.

The authors cautioned that this was an underpowered subgroup analysis. "To adequately power a study comparing clinical outcomes (death, MI, and stroke) between men and women undergoing revascularization for unprotected left main disease, approximately 5,200 patients will be required with power of 80% at an alpha level of 5%," the team estimated.

PCI: How Many Stents?

Finally, if patients with left main bifurcation lesions are to undergo PCI, it is better to use a one-stent strategy and a contemporary drug-eluting stent (DES) at that, a found.

After propensity score matching, major adverse cardiovascular events -- namely cardiac death, acute MI, stent thrombosis, and target lesion revascularization -- were reduced when operators opted for one instead of two stents (4.7% versus 18.6%, HR 3.71, 95% CI 2.55 to 5.39), according to Jung-Sun Kim, MD, PhD, of Korea's Severance Cardiovascular Hospital in Seoul, and colleagues, reporting in the same journal issue.

Similarly, these events were down when a current-generation device was used (4.6% versus 10.9%, HR 0.55, 95% CI 0.34 to 0.89).

"Intervention of left main coronary artery bifurcation lesions using DES implantation demonstrated acceptable long-term clinical outcomes, especially in current-generation DES patients," Kim's group concluded.

The matter of one or two stents appeared to be less definitive: "The historical nature of the early DES data and the low rate of the two-stent strategy in the present DES group do not allow any clear conclusion to be drawn from this study. When the percentage diameter stenosis is >50% in the second vessel, the benefit of a systematic two-stent strategy remains an unanswered question," wrote Bernard Chevalier, MD, of Hôpital Privé Jacques Cartier in France, in an .

"Considering the difficulties in achieving randomized head-to-head comparisons of two-stent techniques in left main bifurcations, which are powered on clinical endpoints, large well-conducted registries of left main interventions collecting detailed information on anatomy and distribution of the plaque burden may play an important role in fine-tuning the strategy," he suggested.

The study's dataset was made up of 1,353 patients included in two Korean registries who got either an early- (n=889) or current-generation DES (n=464). Patients went into PCI for left main lesions with an average SYNTAX score of 22.96; the population was 74.1% men, and 63.9% of the cohort had multivessel disease.

Among patients with contemporary DES, the independent predictors of adverse events were the presence of chronic kidney disease and pre-intervention side branch diameter stenoses of at least 50%, Kim and colleagues reported.