Can History of Myocardial Infarction Reliably Indicate Myocardial Viability in Patients With a Coronary Chronic Total Occlusion and Good Collateral Circulation?

J INVASIVE CARDIOL 2021;33(2):E135. doi:10.25270/jic/20.00514

Key words: chronic total occlusion, myocardial viability, percutaneous coronary intervention

Dear Editors:

We read with interest the study by Shaikh et al¹ reporting that none of the patients with coronary chronic total occlusions (CTOs) and a prior Q-wave myocardial infarction (MI) in the CTO-supplied territory had viable myocardium even in the presence of good collateral circulation.

We examined the association between prior MI and myocardial viability in a large, multicenter, CTO percutaneous coronary intervention (PCI) registry (PROGRESS CTO: Prospective Global Registry for the Study of Chronic Total Occlusion Intervention; clinicaltrials.gov identifier, NCT02061436). Among 355 patients with Rentrop 3 collaterals in whom viability testing was done, a total of 307 had viable myocardium. Among these, almost half (49%) had suffered a prior MI. Of the 154 prior MI patients, 97% had viable myocardium.

Since all patients in our registry underwent CTO-PCI, rates of viable myocardium are expected to be higher than in consecutive patients with a CTO. Also, in PROGRESS-CTO, electrocardiograms are not available to assess for Q wave, as in the study by Shaikh et al. Finally, viability was not assessed only by positron emission tomography scan (13%), but also by single-photon emission computed tomography (52%), echocardiography (19%), and magnetic resonance imaging (15%).

In summary, viability testing may still be of value in patients with a CTO and a prior MI, especially if their ejection fraction is low and dyspnea is the predominant symptom.^1,2

From the Minneapolis Heart Institute and Minneapolis Heart Institute Foundation, Abbott Northwestern Hospital, Minneapolis, Minnesota.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Garcia reports consulting fees from Medtronic. Dr Rangan reports research grants from InfraReDx and Spectranetics. Dr Burke reports consulting and speaker honoraria from Abbott Vascular and Boston Scientific. Dr Brilakis reports consulting/speaker honoraria from Abbott Vascular, American Heart Association (associate editor, Circulation), Boston Scientific, Cardiovascular Innovations Foundation (Board of Directors), CSI, Elsevier, GE Healthcare, InfraRedx, and Medtronic; research support from Regeneron and Siemens; shareholder in MHI Ventures; Board of Trustees for the Society of Cardiovascular Angiography and Interventions. The remaining authors report no conflicts of interest regarding the content herein.

Manuscript accepted August 13, 2020.

Address for correspondence: Emmanouil S. Brilakis, MD, PhD, Minneapolis Heart Institute, 920 East 28th Street #300, Minneapolis, MN 55407. Email: esbrilakis@gmail.com

1. Shaikh MM, Sadiq MA, Nadar SK. Q-waves associated with postinfarct chronic total occlusion arteries predict non-viable myocardium even in the presence of collaterals. J Invasive Cardiol. 2020;32:E213-E215. Epub 2020 Jul 22.
2. Xenogiannis I, Gkargkoulas F, Karmpaliotis D, et al. Temporal trends in chronic total occlusion percutaneous coronary interventions: insights from the PROGRESS-CTO registry. J Invasive Cardiol. 2020;32:153-160.