Rentrop and Cohen’s Collateral Classification

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Overview
Angiographic assessment of apparent collaterals is useful to quantify the angiogenic response to interventions designed to enhance myocardial perfusion and function in ischemic myocardium.


 * Grade 0: No collateral's present.


 * Grade 1: Barely detectable coronary flow. Contrast medium passes through collateral channels but fails to opacify the epicardial vessels at any time.


 * Grade 2: Partial collateral flow. Contrast material enters but fails to opacify the target epicardial vessel completely.


 * Grade 3: Complete perfusion. Contrast material enters and completely opacifies the target epicardial vessel.