391Gadobutrol enhanced CMR to detect significant coronary artery disease defined by quantitative coronary angiography. Results from two blinded phase III clinical trials
Abstract Background The FDA regulated GadaCAD1 trial and the nearly identical GadaCAD2 clinical trial aimed to determine whether gadobutrol-enhanced CMR can detect significant CAD. Methods Two multicenter, international trials enrolled patients with known or suspected CAD and used cine MRI, gadobutrol enhanced stress/rest perfusion, and late gadolinium enhancement. Endpoints, primary, and secondary minimum performance thresholds versus QCA and stress cine MRI are summarized in the table. There were 3 blinded, core-lab CMR readers per trial (6 readers overall) and 2 core-lab QCA readers. A meta-analysis combined results from all 6 CMR readers. Results 765 patients were analyzed (GadaCAD1: n=376, GadaCAD2: n=389). The meta-analysis of 6 readers had 79% sensitivity, 87% specificity, and AUC of 0.82 to detect a 70% QCA stenosis and met all study endpoints (figure & table). Versus a 50% QCA stenosis, the meta-analysis also met all study endpoints. At an individual reader level, all 6 readers met all study endpoints versus a 70% QCA stenosis. Versus a 50% QCA stenosis, only 1 of 6 readers exceeded the minimum performance threshold for sensitivity but all 6 readers met all other endpoints. For all readers, stress perfusion was more sensitive than stress wall motion (p<0.05). Diagnostic Accuracy Results Conclusions CMR stress perfusion has high diagnostic accuracy for significant CAD. The ROC analysis and overall results support prior literature that a 70% QCA threshold is a more appropriate threshold for physiologically significant CAD. Acknowledgement/Funding Bayer