麻豆传媒

Successful recanalization of a native coronary total occlusion (CTO) with a drug-eluting stent (DES) might not yield better long-term outcomes, an observational study found, suggested to be because of subsequent treatment differences.

Successful stenting for CTO was associated with lower odds of target vessel revascularization (4.4% versus 20.9% for failures, hazard ratio 0.15, 95% confidence interval 0.10-0.25) and coronary artery bypass grafting (CABG; 0.4% versus 16.7%, HR 0.02, 95% CI 0.01-0.06) over a median-follow-up period of 4.6 years.

But successful and failed recanalization , , of Asan Medical Center in Seoul, and colleagues reported in JACC: Cardiovascular Interventions:

• For all-cause mortality (8.0% versus 7.1%, HR 1.04, 95% CI 0.53-2.04)
• For cardiac death (5.3% versus 5.1%, HR 1.00, 95% CI 0.45-2.26)
• For myocardial infarction (MI; 1.3% versus 2.1%, HR 0.57, 95% CI 0.16-2.06)
• For stroke (0.5% versus 1.5%, HR 0.29, 95% CI 0.05-1.72)

The survival findings contrasted with previous studies, the researchers noted. "One plausible explanation of this finding is that the revascularization strategy for non-CTO vessels may have affected the clinical outcome," they suggested.

"Accordingly, the high rate of subsequent CABG in patients with failed PCI [percutaneous coronary intervention] may have affected the outcome. Patients referred to an elective CABG following failed PCI can be considered as a 'treated' group, and analyses conducted with these patients in the failed PCI group may attenuate the possible long-term mortality benefit of patients in the successful PCI group," the authors wrote.

A "nagging question remains," , of Virginia Commonwealth University Pauley Heart Center in Richmond, wrote in an accompanying editorial: "Is there a clinical benefit for CTO PCI, particularly as relates to mortality reduction?"

The topic of CTO PCI "provides a new opportunity to address our concept regarding the benefit of limiting/eliminating ischemia," he wrote in an accompanying editorial.

Park's single-center study included 1,004 consecutive native-vessel CTO patients at Park's center from 2003 to 2014. Each received either first- or newer-generation DES during percutaneous coronary intervention (PCI).

The subset of patients who underwent complete revascularization for multiple non-CTO vessels in addition to CTO PCI also showed no advantage in long-term outcomes, including all-cause mortality and MI.

Fully understanding the impact of the ischemia potential for the myocardium supplied by a total occlusion is essential, Vetrovec wrote. The issue is complicated by specific factors such as "is the CTO artery supplied by collaterals, are the collaterals 'sufficient' to prevent ischemia and are the collaterals arising from a vessel with a significant lesion?... Most importantly what is the patient's cardiovascular risk profile and how effectively is it being addressed?"

Citing the high rate of surgical revascularization in the failed PCI cohort, he noted that Park's study "does not completely answer the question of the importance of eliminating ischemia" yet provides findings that are in line with the growing emphasis on complete revascularization.

But that's not enough, Vetrovec emphasized. "Given the expense, risk and management issues related to CTO PCI in optimal coronary disease management, continued retrospective comparative trials of successful vs. unsuccessful CTO PCI seem unlikely to define the value of this technology. It appears time to seriously initiate plans for a randomized trial," he concluded.

Park and colleagues agreed.

"Given the specific clinical and medical angiographic characteristics of CTOs, the optimal medical therapy alone for these complex lesions has been advocated," the authors wrote. It is important to conduct a randomized comparison between CTO-PCI and optimal medical therapy, they added, and the ongoing DECISION-CTO trial may provide the long-awaited answers.