Background: The main goal of coronary revascularization is to restore myocardial perfusion in case of ischemia causing coronary artery disease (CAD). Yet, little is known on the effect of revascularization on absolute myocardial blood flow (MBF). Therefore, the present prospective study assesses the impact of coronary revascularization on absolute MBF as measured by [15O]H2O positron emission tomography (PET) and fractional flow reserve (FFR) in patients with stable CAD.

Methods: Fifty-three Patients (87% men, mean age 58.7 ± 9.0 years) with suspected CAD were included prospectively. All patients underwent serial [15O]H2O PET perfusion imaging at baseline and after revascularization by either percutaneous coronary intervention (PCI) or coronary artery bypass graft surgery (CABG). FFR was routinely measured at baseline and directly post-PCI. Sequential absolute myocardial perfusion was compared and the relationship with FFR was explored.

Results: After revascularization, regional rest and stress MBF improved from 0.77 ± 0.16 to 0.86 ± 0.25 mL·min-1·g-1 and 1.57 ± 0.59 to 2.48 ± 0.91 mL·min-1·g-1, respectively, yielding an increase in coronary flow reserve (CFR) from 2.02 ± 0.69 to 2.94 ± 0.94 (p<0.01 for all). Mean FFR at baseline improved post-PCI from 0.61 ± 0.17 to 0.89 ± 0.08 (p<0.01). After PCI, an increase in FFR paralleled improvement in absolute myocardial perfusion as reflected by stress MBF and CFR (r = 0.74 and r = 0.71, respectively, p<0.01 for both). PCI demonstrated a greater improvement of regional stress MBF as compared with CABG (1.14 ± 1.11 vs. 0.66 ± 0.69 mL·min-1·g-1, respectively, p = 0.02).

Conclusion: Successful coronary revascularization has a significant and positive impact on absolute myocardial perfusion as assessed by serial quantitative [15O]H2O PET. Notably, improvement of FFR after PCI was directly related to the increase in hyperemic MBF. Percutaneous revascularization resulted in a greater improvement of flow reserve as compared to surgical treatment.