Abstract 4236: Detection of CAD with Real Time Perfusion Imaging versus Conventional Harmonic Imaging During Exercise and Dobutamine Stress Echocardiography
Real time perfusion (RTP) imaging techniques during intravenous ultrasound contrast infusions have the potential to improve the detection of coronary artery disease (CAD) during stress testing because they permit the detection of myocardial perfusion (MP), and may better enhance the detection of subendocardial ischemia by providing an endocardial and transmural border, which is not possible with conventional B-mode harmonic imaging (CHI). We hypothesized that RTP imaging would improve the detection of CAD during exercise (ESE) and dobutamine stress echocardiography (DSE) when compared to optimal CHI. The ability to detect patients with significant CAD (defined as either a >50% diameter stenosis by quantitative angiography or negative clinical outcome at six months in low risk patients) was assessed in 393 patients being evaluated for CAD. Of these, 256 underwent DSE or ESE with RTP, and 137 underwent ESE or DSE with conventional harmonic imaging (CHI). A continuous infusion of 3% Definity (Lantheus Inc) was used for all RTP studies, and for CHI studies where endocardial borders were suboptimal. An abnormal study was defined as an inducible myocardial perfusion defect (MPD) or wall thickening (WT) abnormality (subendocardial or transmural) when using RTP, while a transmural WT abnormality was considered abnormal by CHI analysis. Reviewers were blinded to quantitative angiographic results or to clinical outcomes. A total of 228 patients underwent DSE (158 with RTP and 70 with CHI) and 165 underwent ESE (98 with RTP and 67 with CHI). RTP sensitivity was higher than CHI (p=0.001), both because of MP analysis and enhanced detection of WT abnormalities (Table⇓). WT sensitivity improved significantly when using RTP during ESE (p=0.03). The addition of RTP imaging with ultrasound contrast improves stress test sensitivity by both identifying MP abnormalities and improving the detection of WT abnormalities.