Randomized Trial Questions Staged Chronic-Occlusion PCI After Primary PCI

October 14, 2015

SAN FRANCISCO, CA — In a separate procedure within a week or so of PCI for acute ST-segment-elevation MI, opening up a chronic total occlusion (CTO) that had been discovered outside the infarct-related artery (IRA) does not improve left ventricular function or LV volume, suggests a small randomized trial[1]. But such CTO recanalization may well improve LV ejection fraction if the occlusion is in the left anterior descending (LAD) coronary artery, which serves a broader expanse of LV myocardium than the other main coronaries, hinted the study of about 300 patients.

Overall, it suggests that such post–primary-PCI treatment of CTOs, done often at some centers but much more selectively at others—in either case without much hard data for guidance—is at least "feasible and safe" if operators do it in hope of enhancing myocardial perfusion, said Prof Jose PS Henriques (University of Amsterdam, the Netherlands) when reporting the study here at TCT 2015.

Moreover, he and his colleagues "believe that additional PCI of a CTO located in the LAD may improve ejection fraction and potentially improve clinical outcomes during follow-up."

A note of caution, however: there were signs of worsened clinical outcomes in the trial's patients that underwent non-IRA CTO PCI compared with those whose non-IRA CTOs were left alone, although statistical power for that finding was lacking.

Asked whether there was enough statistical power to recommend such staged CTO PCI in the LAD, Henriques told heartwire from Medscape that patients in that situation were "still a large proportion of the total population" of the trial, about 25%. The CTOs were in the right coronary artery (RCA) for almost half the patients.

Prof Jose PS Henriques

He acknowledged that for avid proponents of PCI for CTO, following acute STEMI or not, the study's message "is not very nice." It recommends a wait-and-see approach to CTOs in non-IRA RCAs and left-circumflex (LCx) coronary arteries discovered at primary PCI. But he noted the patient might possibly benefit from PCI of such lesions in the LAD, so that strategy might be considered.

Commenting on the study, Dr Giora Weisz (Columbia University Medical Center, New York, NY) said the findings are consistent with "what most of us see" in clinical practice—that the threshold for treating CTOs in the LAD is lower than for the other main coronaries because it serves so much more myocardium. Weisz wasn't a part of the study.

Patients randomized in the trial at centers in Canada and Europe had undergone PCI for acute STEMI and were then found with a non-IRA CTO; they then either had it treated with PCI within 7 days or did not have the staged procedure.

Co–Primary End points 4 Months After Primary PCI, Staged PCI vs None for Non-IRA CTO

End points PCI for Non-IRA CTO, n=136 No PCI for Non-IRA CTO, n=144 P
LVEF (%) 44.1 44.8 0.597
LVEDV (mL) 215.6 212.8 0.703
LVEF=left ventricular ejection fraction
LVEDV=left ventricular end diastolic volume

For the 69 patients with CTO in the LAD, LVEF over 4 months on average improved by 6.8 points (95% CI 1.1–12.6) for those getting vs not getting staged PCI. For the remainder with non-LAD total occlusions, LVEF fell by a mean of 3.2 points (95% CI, -6.4 to -0.1) with staged PCI vs no staged PCI. The interaction between PCI-treated CTO location and LVEF outcomes was significant (P=0.002).

"This is a very important study" in that it adds a cautionary note to evidence from prior observational and retrospective studies that suggested functional benefits from more broadly applied PCI for CTOs," according to Prof Marco Valgimigli (Thoraxcenter, Rotterdam, the Netherlands), also not part of the trial. Speaking at a media briefing on the study, Valgimigli nonetheless said, "I'm not sure I buy in 100% to the conclusion about the [strategy's] safety and feasibility. I think those four fatal events in the CTO PCI group as compared with the other [group] is a matter of big concern to me."

He was referring to secondary clinical outcomes, which showed numerical increases in major adverse cardiac events (MACE) at 4 months in the group that had PCI of the non-IRA CTO. On the other hand, the study was not adequately powered for clinical outcomes.

MACE 4 Months After Primary PCI, Staged PCI vs None for Non-IRA CTO

End points PCI for Non-IRA CTO, n=136 (%) No PCI for Non-IRA CTO, n=144 (%) P
MACE 5.4 2.6 0.212
Cardiac death 2.7 0 0.056
MI 3.4 1.9 0.494
CABG 0 0.6 1.0

To heartwire , Henriques acknowledged that the deaths in the trial were worrisome, and "it's really something we need to look at." But the study is too small and preliminary to make much of it as a signal, he said.

Speaking during the question-and-answer period after the Henriques formal presentation at TCT 2015, Dr Anthony Gershlick, principal investigator of the CVLPRIT trial that advocated complete revascularization at PCI for STEMI, had reservations about expansive use of PCI for non-IRA CTO after primary PCI. The current study, he said, "is almost a step too far in many ways." CTOs were excluded from CVLPRIT, he observed. "I think these are patients who are relatively stable in terms of their CTO, so I would never consider, I think, undertaking a CTO in the context of after a STEMI."

Before considering it later, he said, "I would want to know that the CTO is [clinically] important, that there was some sort of noninvasive test that suggests that it's important, and ischemia."

Indeed, a recurring theme among observers of the trial at TCT 2015 was that some sort of myocardial viability testing for the area served by the CTO-afflicted artery would help a lot in deciding whether PCI was appropriate. "The fact that the patients have a CTO does not mean that the patients will have an advantage from reopening the CTO if there is no ischemia or viability," noted Valgimigli.

In reply, Henriques did not offer data but did say, based on a yet-incomplete secondary analysis, "the vast majority of the CTOs had supplied viable myocardium." Less than 10% of the CTOs were in vessels serving nonviable myocardium, he said.

Dr Sanjit S Jolly (McMaster University, Hamilton, ON), also not affiliated with the study, told heartwire that "this trial probably should not change practice yet, because it's not definitive, not large enough. It's kind of like a phase 2 trial with drugs where you see some signals in some subgroups that would lead the company to pursue in that subgroup. Given that the clinical outcomes seemed to go into the wrong direction, we actually need to have a larger trial before any guideline committees could make recommendations."

Henriques discloses receiving grant support from Abbott Vascular, Abiomed, Biotronik, and B Braun. Jolly has previously disclosed receiving consultant fees or honoraria from AstraZeneca, research grants from Medtronic, and being on a speaker's bureau for St Jude Medical. Valgimigli has previously disclosed serving as a speaker, advisor, or consultant to the Medicines Company and Terumo Medical.

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