Coronary collaterals and myocardial viability in patients with chronic total occlusions

Stefan P. Schumacher, Henk Everaars, Wijnand J. Stuijfzand, Jennifer W. Huynh, Pepijn A. van Diemen, Michiel J. Bom, Ruben W. de Winter, Ramon B. van Loon, Peter M. van de Ven, Albert C. van Rossum, Maksymilian P. Opolski, Alexander Nap, Paul Knaapen

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Abstract

AIMS: This study aimed to evaluate associations between coronary collaterals and myocardial viability as assessed by quantitative cardiac magnetic resonance (CMR) imaging in patients with a chronic coronary total occlusion (CTO). METHODS AND RESULTS: A total of 218 patients with a CTO who underwent CMR between 2013 and 2018 were included. A concomitant collateral connection (CC) score 2 and Rentrop grade 3 defined well-developed collaterals in 146 (67%) patients, whereas lower CC scores or Rentrop grades characterised poorly developed collaterals. Dysfunctional myocardium (<3 mm segmental wall thickening [SWT]) and ≤50% late gadolinium enhancement (LGE) defined viability. Extensive scar (LGE >50%) was observed in only 5% of CTO segments. In the CTO territory, SWT was greater (3.72±1.51 vs 3.05±1.60 mm, p<0.01) and the extent of scar was less (7.0 [0.1-16.7] vs 13.1% [2.8-22.2], p=0.048) in patients having well-developed versus poorly developed collaterals. Viability was more prevalent in CTO segments among patients with poorly developed versus well-developed collaterals (44% vs 30% of segments, p<0.01), predominantly due to a higher prevalence of dysfunctional myocardium (51% vs 34% of segments, p<0.01) in the poorly developed collateral group. CONCLUSIONS: The infarcted area in myocardium subtended by a CTO is generally limited. Well-developed collaterals are associated with less myocardial scar and enhanced preserved function. However, viability was regularly present in patients with poorly developed collaterals. Visual summary. CMR-derived viability with potential for functional recovery is regularly present in myocardium supplied by poorly developed collaterals in patients with a CTO.

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