Combined analysis of myocardial function, viability, and stress perfusion in patients with chronic total occlusion in relation to collateral flow

Abstract

A b s t r a c tBackground: Indications for revascularisation in chronic total occlusion (CTO) of the coronary artery depend on the interplay between myocardial function, viability, and ischaemia. The technical feasibility of the procedure often relies on the collateral flow to the occluded artery. Aim:To assess the relation between the degree of collateral flow and characteristics of the myocardium supplied by the occluded artery. Methods:The study included 54 patients (mean age 62 years, 85% males) with CTO referred for cardiovascular magnetic resonance (CMR) to assess indications for revascularisation. The presence of well-developed collateral flow was defined as a collateral connection grade = 2 and Rentrop score = 3. Results:The presence of well-developed collaterals (n = 24, 44%) was less likely to be related to systolic dysfunction of the segments supplied by the occluded artery (mean wall motion score index 1.31 ± 0.44 vs. 1.64 ± 0.67, p = 0.04) in comparison to a lack of well-developed collaterals. Patients with well-developed collaterals had a lower frequency of previous myocardial infarction of the CTO territory (38% vs. 67%, p = 0.03) with similar frequency of transmural infarctions (21% vs. 23%, p = 0.83). They less frequently presented perfusion deficits of the CTO area during hyperaemia (42% vs. 70%, p = 0.03) and the size of deficits was smaller (median 0.0% [interquartile range 0-12%] vs. 7.5% [0-15%], p = 0.04). Conclusions:Myocardial segments supplied by CTO with well-developed collaterals are less prone to inducible ischaemia, have better systolic function, and are less likely to undergo myocardial infarction, in comparison to those supplied by CTO with poor collateral circulation. CMR is a non-invasive method that can be used for a comprehensive workup of patients being considered for CTO revascularisation.

Contradictory Effect of Coronary Collateral Circulation on Regional Myocardial Perfusion That Assessed by Quantitative Myocardial Perfusion Scintigraphy

“…In a study investigating the effects of CCC on left ventricular perfusion and function, it was stated that well-developed coronary collaterals reduced left ventricular dysfunction, infarct size, and mortality [16]. In their study Malek et al determined that myocardial segments supplied by chronic total occlusion with good collaterals were less inclined to inducible ischemia and were less likely to un- [28]. However, there are also studies stating that good collateral development does not contribute to myocardial perfusion and viability.…”

Assessment of late gadolinium enhancement-negative chronic total occlusion by longitudinal strain analysis using cardiac magnetic resonance imaging

“…Previous studies have shown that collateral grade has no correlation with fractional flow reserve or affects myocardial infarct size. However, correlation with the probability of myocardial infarction has been demonstrated (29,30), indicating that the extent of myocardial ischemia is influenced by multiple factors, not only collateral circulation. Therefore, collateral circulation might suggest the probability of myocardial abnormalities; however, it was not correlated with the degree of abnormality.…”

Total bilirubin and fasting plasma glucose levels are associated with coronary collateral development in elderly patients

“…A previously published study found that when intermittent ischemia was induced, collateral vessels that were non-functional at rest became functional with exercise [4]. Well-developed coronary collat-eral arteries have been associated with smaller necrotic areas and ventricular aneurysm formation in patients with acute myocardial infarction, resulting in improved heart remodeling, as well as reduced ischemia and chest pain in chronically ill patients [5][6][7]. The development of coronary collateral vessels is thought to occur via both angiogenesis, the formation of new vessels through sprouting of new capillaries from existing blood vessels, and via arteriogenesis, the growth and maturation of existing anastomotic channels between coronary arteries.…”