Impact of Elective Percutaneous Coronary Intervention on Global Absolute Coronary Flow and Flow Reserve Evaluated by Phase-Contrast Cine-Magnetic Resonance Imaging in Relation to Regional Invasive Physiological Indices.

Few studies have documented changes in global absolute coronary blood flow and global coronary flow reserve after percutaneous coronary intervention (PCI) in relation to regional physiological measures. Phase-contrast cine-magnetic resonance of the coronary sinus is a promising approach to quantify global absolute coronary blood flow. We aimed to assess the impact of elective PCI on global absolute coronary blood flow and global coronary flow reserve by quantifying coronary sinus flow (CSF) using phase-contrast cine-magnetic resonance in relation to regional physiological indices. We prospectively studied 54 patients with stable angina undergoing elective PCI for a single proximal lesion. Phase-contrast cine-magnetic resonance was used to assess CSF and CSF reserve at rest and during maximum hyperemia, before and after PCI. Regional physiological indices were obtained during PCI. A complete data set was obtained in 50 patients. Hyperemic CSF increased significantly after PCI (pre-PCI, 230.2 [167.4-282.8] mL/min; post-PCI, 267.4 [224.1-346.2] mL/min; P<0.01), although 12 patients (24.0%) showed a decrease, despite successful PCI and improved fractional flow reserve. CSF reserve numerically, albeit not statistically significant (P=0.19), increased from 2.65 (1.95-3.96) to 2.98 (2.13-4.32). Patients with decreased CSF after PCI were associated with significantly greater pre-PCI hyperemic CSF, lower global coronary vascular resistance, lower regional microcirculatory resistance, and higher fractional flow reserve (all P<0.01). Fractional flow reserve-guided PCI in patients with single de novo lesions was associated with increased absolute hyperemic CSF, although 24% of patients showed decreased hyperemic CSF, despite successful and uncomplicated PCI. The present approach combining regional and global physiological assessments may provide a novel insight into the dynamic behavior of the coronary hemodynamics and microvascular function after PCI.

Kanaji Y ，Yonetsu T ，Hamaya R ，Murai T ，Usui E ，Hoshino M ，Yamaguchi M ，Hada M ，Kanno Y ，Fukuda T ，Ohya H ，Sumino Y ，Sugano A ，Lee T ，Hirao K ，Kakuta T ... -  《-》

Absolute Myocardial Blood Flow After Elective Percutaneous Coronary Intervention Evaluated on Phase-Contrast Cine Cardiovascular Magnetic Resonance Imaging.

Hamaya R ，Sugano A ，Kanaji Y ，Fukuda T ，Kanno Y ，Yonetsu T ，Usui E ，Hoshino M ，Hada M ，Ohya H ，Sumino Y ，Yuki H ，Murai T ，Lee T ，Kakuta T ... -  《-》

Impact of regional functional ischemia on global coronary flow reserve in patients with stable coronary artery disease.

Global coronary flow reserve (g-CFR) provides powerful prognostic information. The relationship between g-CFR and the regional physiological indices of fractional flow reserve (FFR), coronary flow reserve (r-CFR), and the index of microcirculatory resistance remains undetermined. This study aimed to assess the relationship between regional and global physiological indices and determinants of cardiovascular magnetic resonance imaging (CMR)-derived g-CFR. A total of 151 patients with single de novo intermediate to stenotic epicardial lesions referred for diagnostic invasive coronary angiography who underwent phase-contrast cine CMR of the coronary sinus (CS) were included. g-CFR was calculated as the ratio of hyperemic and resting CS flow (CSF). Regional and global physiological parameters were compared, and determinants of g-CFR were assessed. There was a weak linear relationship between FFR and g-CFR (R2=0.04, p=0.013), while r-CFR and g-CFR, or combinations of the other regional-global indices were not significantly correlated. When patients were divided into two groups by FFR of 0.80, there were also no significant differences in global physiological indices between the groups (FFR≤0.80 vs. FFR>0.80; g-CFR: 2.73 vs. 2.61, p=0.48; hyperemic CSF: 3.32 vs. 3.52ml/min/g, p=0.84). Higher high-sensitivity cardiac troponin-I (hs-cTnI) and higher resting CS flow were independently associated with impaired g-CFR, and the combination could efficiently identify patients with g-CFR<2.0. Given weak relationship among global and regional physiological indices, these indices may provide complementary efficacy for prognostication in patients with single-vessel stable coronary artery disease. Combination of hs-cTnI and resting CS flow could estimate g-CFR without pharmacological hyperemic induction.

Hamaya R ，Fukuda T ，Sugano A ，Kanaji Y ，Hada M ，Kanno Y ，Yuki H ，Hoshino M ，Yonetsu T ，Kakuta T ... -  《-》

Coronary physiological assessment combining fractional flow reserve and index of microcirculatory resistance in patients undergoing elective percutaneous coronary intervention with grey zone fractional flow reserve.

The aim of this study is to investigate the association between fractional flow reserve (FFR) values and change in coronary physiological indices after elective percutaneous coronary intervention (PCI). Decision making for revascularization when FFR is 0.75-0.80 is controversial. A retrospective analysis was performed of 296 patients with stable angina pectoris who underwent physiological examinations before and after PCI. To investigate the differences of coronary flow improvement between territories with low-FFR (<0.75) and grey-zone FFR (0.75-0.80), serial changes in physiological indices including mean transit time (Tmn), coronary flow reserve (CFR), and index of microcirculatory resistance (IMR) were compared between these two groups. Compared to low-FFR territories, grey-zone FFR territories showed significantly lower prevalence of Tmn shortening, CFR improvement, and decrease in IMR (Tmn shorting, 63.9% vs. 87.0%, P < .001; CFR improvement, 63.0% vs. 75.7%, P = .019; IMR decrease, 51.3% vs. 63.3%, P = .040) and lower extent of their absolute changes (Tmn shorting, 0.06 (-0.03 to 0.16) vs. 0.22 (0.07-0.45), P < .001; CFR improvement, 0.45 (-0.32 to 1.87) vs. 1.08 (0.02-2.44), P < .01; IMR decrease, 0.2 (-44.0 to 31.3) vs. 2.9 (-2.9 to 11.8), P = .022). Multivariate analysis showed that pre-PCI IMR predicted improved coronary flow profile in both groups, whereas pre-PCI FFR predicted increased coronary flow indices in low-FFR territories. Worsening of physiological indices after PCI was not uncommon in territories showing grey-zone FFR. Physiological assessment combining FFR and IMR may help identify patients who may benefit by PCI, particularly those in the grey zone.

Niida T ，Murai T ，Yonetsu T ，Kanaji Y ，Usui E ，Matsuda J ，Hoshino M ，Araki M ，Yamaguchi M ，Hada M ，Ichijyo S ，Hamaya R ，Kanno Y ，Isobe M ，Kakuta T ... -  《-》

Effect of percutaneous coronary intervention on global hemodynamics and the prevalence of residual microvascular dysfunction.

We aimed to examine the changes in hyperemic coronary sinus flow (CSF) and global coronary flow reserve (g-CFR) after percutaneous coronary intervention (PCI) and investigate the predictors to improve these metrics and the prevalence of residual coronary microvascular dysfunction (CMD). This prospective, single-center study included 118 patients with stable coronary artery disease undergoing PCI for a single proximal lesion. Phase-contrast cine-cardiac magnetic resonance (PC-CMR) was used to assess hyperemic CSF (HCSF) and g-CFR, before and after PCI. Residual CMD was defined as concordantly impaired post-PCI HCSF (<2.3 ml/min/g) and g-CFR (<2.0). HCSF significantly increased, although 38 (32.2%) patients showed a decrease. There was no significant change in g-CFR despite fractional flow reserve (FFR) improvement in all target territories. Concordantly increased HCSF and g-CFR were effectively discriminated by adding PC-CMR-derived information to pre-PCI FFR. Residual CMD was observed in 30 (25.4%) patients and was associated with pre-PCI renal dysfunction and lower pre-PCI rest and hyperemic CSF, but not with pre-PCI regional physiological indices. FFR-guided PCI was associated with increased HCSF, but not with increased g-CFR. After uncomplicated PCI, one-quarter of patients showed residual CMD. Our approach may help identify patients who may benefit from increased coronary perfusion or show residual CMD.

Misawa T ，Kanaji Y ，Sugiyama T ，Hoshino M ，Yamaguchi M ，Hada M ，Nagamine T ，Teng Y ，Nogami K ，Ueno H ，Yasui Y ，Sayama K ，Matsuda K ，Yonetsu T ，Sasano T ，Kakuta T ... -  《-》