Frequency of Myocardial Infarction and Its Relationship to Angiographic Collateral Flow in Territories Supplied by Chronically Occluded Coronary Arteries

Abstract

Background-Despite complete interruption of antegrade coronary artery flow in the setting of a chronic total occlusion (CTO), clinical recognition of myocardial infarction is often challenging. Using cardiac MRI, we investigated the frequency and extent of myocardial infarction in patients with CTO, and assessed their relationship with regional systolic function and the extent of angiographic collateral flow. Methods and Results-We included 170 consecutive patients (median age, 62 years) with angiographically documented CTO. Regional late gadolinium enhancement and wall motion score index were assessed by cardiac MRI with the use of a 17-segment model. Angiographic collateral flow was assessed by the collateral connection grade and the Rentrop score. Evidence of previous myocardial infarction was found in 25% of patients by ECG Q waves, in 69% by regional wall motion abnormality, and in 86% of patients by late gadolinium enhancement. Increased angiographic collateral flow was associated with a lower frequency of Q waves on ECG, and a lower regional wall motion score index, late gadolinium enhancement volume (%), and degree of late gadolinium enhancement transmurality (all P<0.001), as well. Conclusions-The frequency of myocardial infarction in territories subtended

Clinical and angiographic features associated with coronary collateralization in stable angina patients with chronic total occlusion

“…The number is expected to rise as a result of improved survival of patients with acute coronary syndrome, due to rapid advances in medical and interventional therapy for patients with coronary artery disease. Despite the complete interruption of antegrade blood flow caused by heavy atherosclerotic plaque burden or arterial thrombosis, the frequency of myocardial infarction in areas subtended by chronic total occlusion varies considerably (Fefer et al, 2012), and the degree of myocardial injury downstream of epicardial chronic total occlusion is inversely correlated with the degree of angiographic coronary collateral circulation (Choi et al, 2013). Well-developed coronary collaterals have the potential to alleviate myocardial ischemia, preserve residual contractility, reduce cardiovascular events (Regieli et al, 2009;Meier et al, 2012), and even save lives in patients with severe coronary artery occlusion (Meier, 2011).…”

The Human Myocardial Stain as Mitigated by Coronary Collaterals

“…3 In the context of the population of interest and compared with other clinical studies in the field, 4 the present study is well powered, the fact of which renders the mentioned figures reliable. The data shown are well anchored in existing knowledge by illustrating a direct link between infarct size and the occurrence of ECG and LV functional signs of scar.…”

“…The careful work by Choi et al 3 has shown convincingly that increasingly sensitive detectors of myocardial scar raise its prevalence from a mere quarter of the population with chronic occlusion as defined by ECG Q waves to 42% by the history of prior ischemic symptoms suggestive of myocardial infarction, 69% based on the presence of regional left ventricular (LV) wall-motion abnormalities as assessed by cardiac magnetic resonance imaging, and 86% as defined by myocardial late gadolinium enhancement. 3 In the context of the population of interest and compared with other clinical studies in the field, 4 the present study is well powered, the fact of which renders the mentioned figures reliable.…”

“…So far, data from less historical works have, however, indicated an absence of myocardial infarction in 50% of patients with chronic coronary artery occlusion. 2 One of the concluding remarks of the study by Choi and coworkers 3 published in the present issue of Circulation is that "most patients with chronic coronary artery occlusions show evidence of prior myocardial infarction." Are we on the way back to Cohnheim's paradigm?…”

“…Are we on the way back to Cohnheim's paradigm? Maybe not, because Choi et al 3 reassure the reader that it is the presence of coronary collaterals that mitigates the transmural extent of myocardial scar and regional wall-motion abnormalities ( Figure 1). …”