Abstract 20542: Novel Quantitative Fluoroperfusion Method Accurately Assesses the Physiologic Significance of Coronary Stenoses during Dynamic Cine Fluoroscopy
Background: Invasive coronary angiography is the gold standard for defining percent diameter stenosis. However, it cannot determine the physiologic significance of coronary stenosis without performing a fractional or coronary flow reserve (CFR). The primary aim of this study was to validate a novel quantitative fluoroperfusion (FP) method to measure myocardial blood flow (MBF) and CFR.
Methods: Seven porcine models of myocardial ischemia were prepared with a moderate to severe stenosis in the left anterior descending or left circumflex artery. Selective angiography of the left main was performed using iopamidol (370 mgI/ml) at 3 ml/sec for 5 seconds at rest followed by adenosine stress (0.14 mg/kg/min X 5 minutes) with corresponding radio- labeled microsphere injections to document MBF. Using fluoroscopy images, time-attenuation curves were constructed for the artery, ischemic, and remote myocardium. K1, the first order transfer constant describing the transfer of arterial contrast to the myocardium, was calculated using the Patlak plot method,corrected for the extraction of contrast, expressed in FP units, and compared with MBF. CFR was also calculated from K1 and compared with MBF.
Results: Mean MBF in stenosed vs. remote territories was 1.9±1.1 and 2.5±1.4 ml/g/min at baseline (p=NS) and 1.9±0.9 and 4.0 ±2.1 ml/g/min during adenosine infusion (p<0.01), respectively. There was a significant linear association between FP units and microsphere MBF over the range of flows (R = 0.83, p < 0.001). Mean CFR by FP vs. MBF was 1.7±1.0 and 1.4±0.8, respectively (mean difference: 0.3; 95%CI −1.5–1.0). FP derived CFR strongly correlated with microspheres in the stenosed (R=0.92, p<0.01) and all territories (R=0.75, P<0.01).
Conclusions: In conclusion, quantitative fluoroperfusion provides accurate measurements of regional MBF and CFR. This method has the potential to measure the physiologic significance of coronary stenoses without the need for an intracoronary wire.
- © 2010 by American Heart Association, Inc.