Myocardial Perfusion Imaging After Coronary Artery Bypass Surgery Using Cardiovascular Magnetic ResonanceClinical Perspective: A Validation Study

Background— Absolute quantification of perfusion with cardiovascular magnetic resonance has not previously been applied in patients with coronary artery bypass grafting (CABG). Owing to increased contrast bolus dispersion due to the greater distance of travel through a bypass graft, this approach may result in systematic underestimation of myocardial blood flow (MBF). As resting MBF remains normal in segments supplied by noncritical coronary stenosis ( Methods and Results— The study population comprised 28 patients undergoing elective CABG for treatment of multivessel coronary artery disease. Eligible patients had angiographic evidence of at least 1 myocardial segment subtended by a noncritically stenosed coronary artery ( P =0.57). In the latter, MBF after revascularization did not change significantly from baseline (0.86±0.20 mL/min/g, P =0.82). Conclusions— Model-independent deconvolution analysis does not systematically underestimate blood flow in graft-subtended territories, justifying the use of this methodology to evaluate myocardial perfusion in patients with CABG.