Japanese Registry Finds No Mortality Benefit with CTO PCI Even When Successful

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Successful percutaneous coronary intervention (PCI) of chronic total occlusions (CTOs) imparts no long-term survival advantage compared with failed attempts, according to a Japanese registry study published online June 1, 2013, ahead of print in the American Journal of Cardiology.

Masahiro Natsuaki, MD, of the Kyoto University Graduate School of Medicine (Kyoto, Japan), and colleagues looked at 2,491 patients with at least 1 CTO lesion who were treated at 26 Japanese centers participating in the CREDO Kyoto PCI/CABG Registry Cohort 2 between 2005 and 2007. PCI was attempted in 1,524 patients (61%).

After Adjustment, Only CABG and Repeat Revascularization Reduced

In all, 1,192 patients (78.2%) had successful procedures (defined as final diameter stenosis < 50% and TIMI flow of 2 or 3) and 332 (21.8%) had failed procedures.

There were multiple baseline differences between the 2 groups. For example, patients with failed CTO PCI were more likely to present with acute MI, shock, multivessel disease, and moderate to severe mitral regurgitation and more apt to be undergoing dialysis, while successfully treated patients had a higher prevalence of previous MI. Failed CTO-PCI lesions were more likely to be located in the RCA. Aspirin and thienopyridine use were more common with successful PCI, while nitrates were used more often with failed PCI.

After successful compared with failed PCI, there was a trend toward fewer in-hospital deaths (1.4% vs. 3.0%) and fewer MIs (0.8% vs. 2.1%; both P = 0.053).

At 3-year follow-up, the cumulative incidence of all-cause death was similar between the 2 groups, though cardiac death and the subsequent need for CABG or any coronary revascularization were lower after successful CTO PCI. But after adjustment for potential confounders, only the differences in subsequent procedures remained significant (table 1).

Table 1. Three-Year Outcomes After CTO PCI

Post hoc subgroup analyses suggested that successful PCI may be more effective at reducing 3-year cardiac death risk in patients with single-vessel disease (P = 0.01), no history of heart failure (P = 0.004), and LAD lesions (P = 0.04) and in those without diabetes (P = 0.04).

While acknowledging that successful CTO PCI could be associated with improved survival in some groups, the study authors urged caution given the negative overall results. "Prospective randomized trials comparing PCI plus medical therapy with medical therapy alone in patients with CTO, adequately powered for evaluating long-term mortality, are absolutely required to define the indication of CTO PCI," they conclude, mentioning the ongoing DECISION-CTO trial.

Outside Sources Express Skepticism

In an e-mail communication with TCTMD, Dr. Natsuaki maintained that "in this study, there was no significant difference between the successful CTO-PCI group and the failed group in terms of the risk of long-term mortality."

Nevertheless, David Antoniucci, MD, of Careggi Hospital (Florence, Italy), remained unconvinced that successful CTO PCI was not beneficial. "The lack of difference in all-cause mortality is due mainly to the small sample size and [lack of] statistical power," he told TCTMD in an e-mail communication. "Looking at the incidence of death, cardiac death, myocardial infarction, CABG and any revascularization through the follow-up, patients with successful CTO-PCI did better than [with] CTO PCI failure."

Dr. Antoniucci also highlighted the fact that PCI was never even attempted in approximately 50% of patients with CTOs in the registry. Moreover, he said, there were no predefined criteria for CTO PCI.

"In my opinion, if the territory supplied by the CTO vessel is viable and is more than 10% of the left ventricle, there is a strong indication for PCI whatever the anatomy of the lesion. The benefit of successful PCI increases in patients with multivessel disease and eventually multiple CTO, and with left ventricular dysfunction," Dr. Antoniucci commented. Importantly, he said, the definition of CTO in the study—complete obstruction of the vessel with TIMI flow 0 or 1 and an estimated duration of greater than 1 month after the last MI in the target vessel territory, or presence of collateral flow—is not as stringent as the accepted definition, which is an occlusion lasting more than 3 months, independent of MI history.

"Many patients with true CTO have no history of myocardial infarction" he continued. "Conversely, many patients admitted with AMI have also CTO of the noninfarct vessel, and it has been shown that in this subset of patients the detrimental impact of CTO on outcome is very strong."

In a telephone interview with TCTMD, Jeffrey W. Moses, MD, of Columbia University Medical Center/Weill Cornell Medical Center (New York, NY), called the idea that there is no mortality difference between successful vs. failed CTO PCI "ridiculous."

In particular, the reduction in cardiac mortality, though not significant, was more than 25%, he emphasized. "It’s a strong trend. . . . And obviously, if they followed them for 4 or 5 years, given the separation of the curves, it’s very likely you would see a difference." The number of events at 3 years, Dr. Moses said, is too small to draw definitive conclusions about survival.

Moreover, the disparity in subsequent revascularization, particularly CABG, between successful and failed cases is "major," he said, "which is a pretty compelling reason to do [CTO PCI] in its own right." Symptoms and quality of life, not addressed by the current study, are the main reasons for performing CTO PCI in the first place, Dr. Moses noted.

Source:

Yamamoto E, Natsuaki M, Morimoto T, et al. Long-term outcomes after percutaneous coronary intervention for chronic total occlusion (from the CREDO-Kyoto Registry Cohort-2). Am J Cardiol. 2013;Epub ahead of print.

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