Registry Study: Survival Benefit for Treating CTO After Primary PCI

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Patients undergoing primary percutaneous coronary intervention (PCI) may derive better long-term survival from additional treatment of a chronic total occlusion (CTO) in a major noninfarct-related artery within 30 days, suggests a registry study published online September 25, 2014, ahead of print in the American Journal of Cardiology.

Methods
David Antoniucci, MD, of Careggi Hospital (Florence, Italy), and colleagues examined data from 1,911 patients who underwent successful primary PCI for an acute MI from 2003 to 2012; 11% also had a CTO in a noninfarct-related artery. After excluding patients with a side-branch CTO and those who died during the first week after primary PCI, there were 169 patients (mean age 67; 77% men) with a CTO in a major artery left for analysis. The artery blocked by the CTO was the RCA in 47.9%, the LAD in 22.5%, and the LCX in 29.6%.
Of those, 58 patients underwent successful CTO PCI within the next 30 days and 111 had either a failed procedure or did not undergo attempted revascularization. All patients with successful CTO PCI received DES, and 88% had a complete revascularization.


Better Outcomes With Successful CTO PCI

At 1 year of follow-up, the rate of cardiac death was 8.3% (10 patients died from refractory congestive heart failure and 4 from probable/possible stent thrombosis). The rate was lower among those who underwent successful CTO PCI compared with failed/nonattempted procedures (1.7% vs 12%; P = .025). A similar gap was seen at 3 years (3.7% vs 14.9%; P = .03), with no difference between the failed and nonattempted groups in long-term cardiac survival.

Multivariate analysis showed that successful CTO PCI was independently associated with a reduction in 3-year cardiac mortality (HR 0.20; 95% CI 0.05-0.92), a finding consistent in a model adjusting for propensity score.

Angiographic follow-up revealed no difference in restenosis in the infarct-related artery between those who did or did not undergo successful CTO PCI. In the successful CTO PCI group, nonocclusive restenosis of the CTO occurred in 7 patients (15%) and CTO reocclusion occurred in 2 patients (4.3%). All but 1 of these patients underwent repeat PCI of the CTO vessel.

On echocardiography, left ventricular function improved in both the successful CTO PCI and the failed/nonattempted groups through 6 months, although the gain was greater in those with successful CTO PCI (8% vs 5%; P = .039).

Multiple Possible Reasons for Mortality Benefit

Two potential mechanisms to explain the lower rate of mortality in the successful CTO PCI group, according to the study authors, are “the recovery or improvement of contractile function in the CTO territory, which translates into a greater improvement of left ventricular function after a successful primary PCI as shown in our study, and the prevention or reduction of left ventricular remodeling, also with the healing improvement of the overlapping border in the infarct zone.”

In addition, they write, the difference might be explained by a decrease in the risk of fatal arrhythmia due to a decline in electrical instability, a greater tolerance to future ischemia, or the benefits of complete revascularization.

Randomized Trials Point in the Same Direction

Dr. Antoniucci and colleagues point to the PRAMI trial to support the advantages of complete revascularization in acute MI, although that trial excluded patients with CTO.

“Conversely, in this study we included all patients with [noninfarct-related-artery] CTO, left main disease, or complex anatomy,” they write. “Thus, despite the intrinsic limitations of the nonrandomized design, our study provides original data on the outcome of patients treated for CTO and multivessel disease after successful primary PCI, and the results suggest a strong impact on survival of successful CTO PCI and of completeness of revascularization.”

The study is somewhat an extension of the PRAMI and CvLPRIT trials, according to David E. Kandzari, MD, of the Piedmont Heart Institute (Atlanta, GA).

“These data remind us that successful CTO PCI is an integral part of achieving completeness of revascularization and that this—along with many other studies—is indicating that achieving completeness of revascularization in PCI in general is associated with improved clinical benefit,” he told TCTMD in a telephone interview. He noted, however, that because of the modest sample size and the nonrandomized design, the findings should be considered hypothesis-generating.

Dr. Antoniucci and colleagues acknowledge that “the benefit of the strategy of complete revascularization in this high-risk subset of patients with AMI should be confirmed by randomized studies.”

But Jeffrey W. Moses, MD, of Columbia University Medical Center/Weill Cornell Medical Center (New York, NY), was skeptical that such a trial could be completed given that the convergence of evidence from acute MI and CTO literature in stable coronary disease suggests a benefit for complete revascularization. That makes it difficult to randomize patients to no revascularization of the CTO, he said in a telephone interview.

Dr. Moses added that CTO trials also are complicated by variability in capabilities for CTO treatment and in the quality of operators.

 


Source:
Valenti R, Marrani M, Cantini G, et al. Impact of chronic total occlusion revascularization in patients with acute myocardial infarction treated by primary percutaneous coronary intervention. Am J Cardiol. 2014;Epub ahead of print.

 

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Todd Neale is the Associate News Editor for TCTMD and a Senior Medical Journalist. He got his start in journalism at …

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Disclosures
  • The paper contains no statement regarding conflicts of interest for Dr. Antoniucci.
  • Dr. Kandzari reports receiving research/grant support from Abbott Vascular, Biotronik, Boston Scientific, and Medtronic and serving as a consultant for Boston Scientific and Medtronic.
  • Dr. Moses reports serving as a consultant for Boston Scientific.

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