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Drug-eluting stents for unprotected left-main coronary disease had a 17.7% incidence of in-stent restenosis, which appeared to have a benign clinical course, data from a large clinical series suggested.

During a median follow-up of 32 months after treatment of in-stent restenosis, no patient died, one myocardial infarction (MI) occurred, and six of the 71 patients required repeat target-vessel revascularization, as reported online in the Journal of the American College of Cardiology.

"The clinical consequences of left-main coronary artery in-stent restenosis after drug-eluting stent treatment seemed to be benign, with the incidence of major adverse cardiac events not differing significantly among treatment modalities, given that these patients were optimally treated with the clinical judgment of the treating physician," Jong-Young Lee, MD, of the University of Ulsan in Seoul, South Korea, and co-authors wrote in conclusion.

Clinical guidelines recommend coronary artery bypass surgery for treatment of unprotected left-main coronary disease. Nonetheless, use of percutaneous coronary interventions (PCIs) has increased as techniques and drug therapy have improved, the authors noted.

The introduction of drug-eluting stents has encouraged use of PCI for unprotected left-main disease, because of the devices' low rates of restenosis and need for repeat revascularization, they continued.

In-stent restenosis remains an issue with drug-eluting stents, however, as the lesions tend to be more problematic compared with other types of coronary lesions. But the frequency of in-stent restenosis and the long-term consequences have not been thoroughly examined, providing a rationale for study by Lee and co-authors.

Defining clinically significant coronary disease as stenosis ≥50%, investigators deployed drug-eluting stents in 509 consecutive patients with unprotected left-main disease. Subsequently, 402 patients remained in routine surveillance or clinically driven angiographic follow-up.

The primary endpoint was the rate of major adverse cardiac events, comprising the composite of death, MI, or target-lesion revascularization.

Repeat revascularization was indicated by restenosis of at least 50% of the target lesion in association with a positive stress test, ischemic ECG changes, or ischemic symptoms. A restenosis ≥70% was treated regardless of the presence or absence of ischemic signs or symptoms. Asymptomatic patients with restenosis of 50% to 70% received optimal medical therapy.

During follow-up, 71 (17.7%) of the 402 patients developed angiographically confirmed in-stent restenosis, which was focal in 57 cases and diffuse in 14.

Multivariate analysis identified five predictors of in-stent restenosis: male sex (P=0.007), prior restenotic lesion (P<0.001), bifurcation involvement (P=0.009), complex stenting that required two or more stents in the bifurcation (P=0.007), and total number of stents deployed (P<0.001).

Lee and co-authors reported that 40 (56.3%) of the 71 patients underwent repeat PCI, 10 (14.1%) had coronary bypass surgery, and 21 (29.6%) received medical therapy.

The overall rate of major cardiac adverse events was 13.4% and did not differ by the treatment modality employed for in-stent restenosis.

The authors acknowledged several limitations of their study, including the retrospective nature of the analysis and the small number of patients in each treatment group, which precluded intergroup comparisons. Additionally, the authors noted that first-generation drug-eluting stents were used in the study, making the applicability of the data to current stent technology uncertain.

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