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

OBJECTIVES: Despite complete interruption of antegrade coronary artery flow in the setting of a chronic total occlusion (CTO), clinical recognition of myocardial infarction (MI) is often challenging. Using cardiac magnetic resonance imaging (CMR), we investigated the frequency and extent of MI in patients with CTO, and assessed their relationship with regional systolic function and the extent of angiographic collateral flow.

METHODS: We included 170 consecutive patients (median age 62 years) with angiographically documented CTO. Regional late gadolinium enhancement (LGE) and wall motion score index (WMSI) were assessed by CMR using a 17-segment model. Angiographic collateral flowwas assessed by the collateral connection grade and the Rentrop score.

RESULTS: Evidence of prior MI was found in 25% of patients by ECG Q waves, in 69% by regional wall motion abnormality, and in 86% of patients by LGE. Increased angiographic collateral flow was associated with a lower frequency of Q waves on ECG, as well as a lower regional WMSI, LGE volume (%), and degree of LGE transmurality (all p<0.001).

CONCLUSIONS: The frequency of MI in territories subtended by CTO is significantly higher than previously recognized. The degree of myocardialinjury downstream epicardial CTO is inversely correlated with the degree of angiographic collaterals. Rashaad Penny Jersey

PMID: 23277308

Posted in Invasive Imaging, Magnetic Resonance Imaging and tagged , , .

One Comment

  1. A very interesting study which nicely confirms why there are differing extents of infarction related to CTO – it’s about the collaterals.

    There is actually almost no prospective evidence, as far as I am aware, that opening a CTO improves clinical outcomes or LVEF. The reason may well be that many CTOs do not cause extensive enough wall motion abnormality for PCI to be of benefit.

    There’s a need for a prospective trial using CMR to select CTO patients for PCI. Those with wall motion abnormalities but minimal LGE would be expected to benefit. Is anyone aware of such a study? I don’t believe it has been done.

Leave a Reply

Your email address will not be published. Required fields are marked *