Non-Invasive Evaluation of Coronary Collateral Arterial Flow by Coronary Computed Tomography Angiography
Background—Coronary collateral flow is alternative source of myocardial perfusion in patients with totally occluded coronary arteries. Clinical evaluation of collateral flow has been limited by the need of invasive measurements. We investigated whether non-invasive coronary computed tomography (CT) angiography can evaluate the angiographic extent of coronary collateral flow.
Methods and Results—We enrolled 325 coronary CT angiography cases with angiographically confirmed chronic total occlusion (median age 63 years, male gender 83%). Transluminal attenuation gradient (TAG), which reflects kinetics of contrast media in coronary artery, of an entire artery (TAGall) and distal vessel (TAGdistal) were assessed to evaluate the flow in entire vessel and distal vessel, respectively. TAGs were validated against visually assessed angiographic Collateral Connection and Rentrop grading. TAGall increased consistently according to the angiographic extent of collateral flow (p<0.001). Well-developed collaterals, defined by highest Collateral Connection and Rentrop grades (N=103), could be predicted by TAGall (cutoff ≥ -7.6 HU/10mm; c-statistics=0.72; sensitivity=65%, specificity=73%, positive predictive value (PPV)=52%, negative predictive value (NPV)=82%). TAGdistal could discriminate the antegrade (N=143) and retrograde (N=182) flow in distal artery (cutoff= 0.0 HU/10mm; c-statistics=0.88; sensitivity=78%, specificity=85%, PPV=87%, NPV=75%).
Conclusions—TAG, an intracoronary attenuation-based analysis of coronary CT angiography, moderately reflected the functional extent and direction of collateral flow.
- Received July 31, 2013.
- Accepted March 27, 2014.