Abstract
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Background: In stable CAD, the optimal revascularization strategy remains unclear. Trial data suggest that revascularization might not improve myocardial blood flow (MBF) despite producing angiographically favorable results. Improved outcomes are predicted by both higher stress myocardial blood flow (sMBF) and the novel metric coronary flow capacity (CFC). We hypothesized that improvement in sMBF after revascularization is dependent on baseline reversible perfusion defects and/or severe reduction in CFC. Methods: We prospectively enrolled 50 patients (66±10, 70% M) who underwent pre-revascularization cardiac positron emission tomography (PET1), and were then revascularized at the operator’s discretion, largely based on lesions' angiographic appearance. Patients underwent another PET within 90 days post-revascularization (PET2). Changes in whole-heart sMBF were assessed based on baseline perfusion and CFC abnormalities. “Concordant patients” had revascularization only in territories with abnormal perfusion and/or severe reduction in CFC. “Discordant patients” had revascularization only in territories without abnormal perfusion and without reduction in CFC. “Mixed concordance patients” had revascularization to both normal and abnormal regions. Results: Overall, between PET1 and PET2, whole-heart sMBF increased by 12%: 1.26 vs 1.35 cc/min/g, p=0.002. In concordant patients, median whole-heart sMBF increased by 22%: 1.11 to 1.28 cc/min/g, p<0.001, but in discordant patients there was no change (1.43 to 1.37 cc/min/g, p=0.37), even though angiographic appearance-based revascularization had been performed. In mixed concordance, whole-heart sMBF did increase, but less than in full concordance (1.26 to 1.60 cc/min/g, p=0.01; a median 15% change). Conclusions: Revascularization improves whole-heart sMBF, but only when PET perfusion and/or CFC abnormalities are present at baseline.