Association of Coronary Computed Tomography-Defined Myocardial Bridge With Pre- and Post-Procedural Fractional Flow Reserve in Patients Undergoing Elective Percutaneous Coronary Intervention.

BACKGROUND: Myocardial bridge (MB) is a common coronary anomaly characterized by a tunneled course through the myocardium. Coronary computed tomography angiography (CCTA) can identify MB. The impact of MB detected by CCTA on coronary physiological parameters before and after percutaneous coronary intervention (PCI) is unknown.Methods and Results: We investigated 141 consecutive patients who underwent pre-PCI CCTA and fractional flow reserve (FFR)-guided elective PCI for de novo single proximal lesions in the left anterior descending artery (LAD). We compared clinical demographics and physiological parameters between patients with and without CCTA-defined MB. MB was identified in 46 (32.6%) patients using pre-PCI CCTA. The prevalence of diabetes was higher among patients with MB. Median post-PCI FFR values were significantly lower among patients with than without MB (0.82 [interquartile range 0.79-0.85] vs. 0.85 [interquartile range 0.82-0.89]; P=0.003), whereas pre-PCI FFR values were similar between the 2 groups. Multivariable linear regression analysis revealed that the presence of MB and greater left ventricular mass volume in the LAD territory were independently associated with lower post-PCI FFR values. Multivariable logistic regression analysis also revealed that the presence of MB and lower pre-PCI FFR values were independent predictors of post-PCI FFR values ≤0.80. CONCLUSIONS: CCTA-defined MB independently predicted both lower post-PCI FFR as a continuous variable and ischemic FFR as a categorical variable in patients undergoing elective PCI for LAD.

Predictors of Optical Coherence Tomography-Defined Calcified Nodules in Patients With Acute Coronary Syndrome　- A Substudy From the TACTICS Registry.

BACKGROUND: Recent studies suggest that the presence of calcified nodules (CN) is associated with worse prognosis in patients with acute coronary syndrome (ACS). We investigated clinical predictors of optical coherence tomography (OCT)-defined CN in ACS patients in a prospective multicenter registry.Methods and Results: We investigated 695 patients enrolled in the TACTICS registry who underwent OCT assessment of the culprit lesion during primary percutaneous coronary intervention. OCT-CN was defined as calcific nodules erupting into the lumen with disruption of the fibrous cap and an underlying calcified plate. Compared with patients without OCT-CN, patients with OCT-CN (n=28) were older (mean [±SD] age 75.0±11.3 vs. 65.7±12.7 years; P<0.001), had a higher prevalence of diabetes (50.0% vs. 29.4%; P=0.034), hemodialysis (21.4% vs. 1.6%; P<0.001), and Killip Class III/IV heart failure (21.4% vs. 5.7%; P=0.003), and a higher preprocedural SYNTAX score (median [interquartile range] score 15 [11-25] vs. 11 [7-19]; P=0.003). On multivariable analysis, age (odds ratio [OR] 1.072; P<0.001), hemodialysis (OR 16.571; P<0.001), and Killip Class III/IV (OR 4.466; P=0.004) were significantly associated with the presence of OCT-CN. In non-dialysis patients (n=678), age (OR 1.081; P<0.001), diabetes (OR 3.046; P=0.014), and Killip Class III/IV (OR 4.414; P=0.009) were significantly associated with the presence of OCT-CN. CONCLUSIONS: The TACTICS registry shows that OCT-CN is associated with lesion severity and poor clinical background, which may worsen prognosis.

Prognostic Implications of Fractional Flow Reserve and Coronary Flow Reserve After Drug-Eluting Stent Implantation.

BACKGROUND: Fractional flow reserve (FFR) after percutaneous coronary intervention (PCI) provides prognostic information, but limited data are available regarding prognostication using post-PCI coronary flow reserve (CFR). In this study we aimed to assess the prognostic value of post-procedural FFR and CFR for target vessel failure (TVF) after PCI.Methods and Results: This lesion-based post-hoc pooled analysis of previously published registry data involved 466 patients with chronic coronary syndrome with single-vessel disease who underwent pre- and post-PCI FFR and CFR measurements, and were followed-up to determine the predictors of TVF. The prognostic value of post-PCI CFR and FFR was compared with that of FFR or CFR alone. Post-PCI FFR/CFR discordant results were observed in 42.5%, and 10.3% of patients had documented TVF. Receiver-operating characteristic curve analysis revealed that the optimal cutoff values of post-PCI FFR and CFR to predict the occurrence of TVF were 0.85 and 2.26, respectively. Significant differences in TVF were detected according to post-PCI FFR (≤0.85 vs. >0.85, P=0.007) and post-PCI CFR (<2.26 vs. ≥2.26, P<0.001). Post-PCI FFR ≤0.85 and post-PCI CFR <2.26 were independent prognostic predictors. CONCLUSIONS: After PCI completion, discordant results between FFR and CFR were not uncommon. Post-PCI CFR categorization showed incremental prognostic value for predicting TVF independent of post-PCI FFR risk stratification.

Reasons for lesion uncrossability as assessed by intravascular ultrasound.

OBJECTIVES: The purpose of the current study was to use intravascular ultrasound (IVUS) to clarify anatomical and morphological lesion characteristics of uncrossable lesions. BACKGROUND: Uncrossable lesions are not always severely calcified. The prevalence of uncrossable lesions that are nonseverely calcified as well as other mechanisms for uncrossability has not been well clarified. METHODS: A total of 252 de novo uncrossable lesions in native coronary arteries that underwent either rotational or orbital atherectomy due to inability of any balloon to cross the lesion and 38 lesions with severe calcium in which IVUS crossed preatherectomy were included. Severe calcium is defined as maximum arc of calcium ≥270°. RESULTS: Severe calcification was absent in 16% of uncrossable lesions, 83% of which had a significant vessel bend. Compared with crossable lesions with severe calcium, uncrossable lesions with severe calcium more often had a bend in the vessel (71% vs. 21%, p < 0.001) and a longer length of continuous severe calcium (median length of calcium ≥270° 3.8 mm vs. 1.9 mm, p = 0.001). Other than severe calcium (especially long continuous calcium) or a bend in the vessel, anatomical factors associated with uncrossabilty were aorto-ostial lesion location and small vessels. CONCLUSIONS: Uncrossable lesions are not always severely calcified. The interaction of lesion morphology (continuous long and large arcs of calcium) and vessel geometry (bend in the vessel or ostial lesion location) affect lesion crossability.

Comparison of 6-month vascular healing response after bioresorbable polymer versus durable polymer drug-eluting stent implantation in patients with acute coronary syndromes: A randomized serial optical coherence tomography study.

OBJECTIVES: This study was conducted to use optical coherence tomography (OCT) to compare vascular healing between bioresorbable polymer (BP) and durable polymer (DP) everolimus-eluting stents (EES) in patients with acute coronary syndromes (ACS). BACKGROUND: Whether BP-EES induce better vascular healing compared to contemporary DP-EES remains controversial, especially for ACS. METHODS: In this prospective, randomized, non-inferiority trial, we used OCT to compare 6-month vascular healing in patients with ACS randomized to BP versus DP-EES: percent strut coverage (primary endpoint, non-inferiority margin of 2.0%) and neointimal thickness and percent neointimal hyperplasia (NIH) volume. As an exploratory analysis, morphological factors related to the endpoints and the effect of underlying lipidic plaque on stent healing were evaluated. RESULTS: A total of 104 patients with ACS were randomly assigned to BP-EES (n = 52) versus DP-EES (n = 52). Of these, 86 patients (40 BP-EES and 46 DP-EES) were included in the final OCT analyses. Six-month percent strut coverage of BP-EES (83.6 ± 11.4%) was not non-inferior compared to those of DP-EES (81.6 ± 13.9%), difference 2.0% (lower 95% confidence interval-2.6%), pnon-inferiority  = 0.07. There were no differences in neointimal thickness 70.0 ± 33.9 µm versus 67.2 ± 33.9 µm, p = 0.71; and percent NIH volume 7.5 ± 4.7% versus 7.3 ± 5.3%, p = 0.85. By multivariable linear regression analysis, stent type was not associated with percent strut coverage or percent NIH volume; however, percent baseline embedded struts or stent expansion was positively associated with percent NIH volume. Greater NIH volume was observed in lipidic compared with non-lipidic segments (8.7 ± 5.6% vs. 6.1 ± 5.2%, p = 0.005). CONCLUSIONS: Six-month strut coverage of BP-EES was not non-inferior compared to those of DP-EES in ACS patients. Good stent apposition and expansion were independently associated with better vascular healing.

Clinical Significance of Increased Computed Tomography Attenuation of Periaortic Adipose Tissue in Patients With Abdominal Aortic Aneurysms.

BACKGROUND: Recent imaging studies reported an association between vascular inflammation and progression of abdominal aortic aneurysm (AAA). This study investigated the clinical significance of periaortic adipose tissue inflammation derived from multidetector computed tomography angiography (MDCTA).Methods and Results:Patients with asymptomatic AAA (n=77) who underwent an index and >6 months follow-up MDCTA examinations were retrospectively investigated. MDCTA analysis included AAA diameter and the periaortic adipose tissue attenuation index (PAAI). The PAAI was defined as the mean CT attenuation value within a predefined range from -190 to -30 Hounsfield units of adipose tissue surrounding the AAA. The growth rate of the AAA was calculated as the change in diameter. AAA progression (AP) was defined as an AAA growth rate ≥5 mm/year. Univariate and multivariate logistic regression analysis were performed to determine the predictors of AP. AP was observed in 19 patients (24.7%), the median baseline AAA diameter was 38.9 mm (interquartile range [IQR] 32.7-42.9 mm), and the median growth rate was 3.1 mm/year (IQR 1.5-4.9 mm/year). Baseline AAA diameter (odds ratio [OR] 1.16; 95% confidence interval [CI] 1.05-1.28; P=0.001) and PAAI (OR 1.12; 95% CI 1.05-1.20; P=0.004) were independent predictors of AP. CONCLUSIONS: PAAI was an independent and significant predictor of AP, supporting the notion that local adipose tissue inflammation may contribute to aortic remodeling.

Impact of pericoronary adipose tissue inflammation on left ventricular hypertrophy and regional physiological indices in stable coronary artery disease patients with preserved systolic function.

Systemic low-grade inflammation has been shown to be associated with left ventricular hypertrophy (LVH). However, the relationship between pericoronary adipose tissue attenuation (PCATA) and both LVH and regional physiological indices remains unknown. This study aimed to evaluate the association of PCATA with LVH and regional physiological indices in stable coronary artery disease (CAD) patients with preserved systolic function. A total of 114 CAD patients who underwent coronary CT angiography (CTA) and invasive physiological tests showing ischemia due to a single de novo lesion were included in the study. On proximal 40-mm segments of all three major coronary vessels on CTA, PCATA was assessed by the crude analysis of the mean CT attenuation value [- 190 to - 30 Hounsfield units [HU)] and the culprit vessel PCATA was used for the analysis. Regional physiological indices were invasively obtained by pressure-temperature sensor-tipped wire. The patients were divided into three groups by culprit vessel PCATA tertiles, and clinical, CTA-derived, and physiological indices were compared. Univariable and multivariable analyses were further performed to determine the predictors of LVH. Angiographic stenosis severity, culprit lesion locations, culprit vessel fractional flow reserve, coronary flow reserve, index of microcirculatory resistance, total and target vessel coronary calcium score, and biomarkers including high-sensitivity C-reactive protein were not different among the groups. The left ventricular (LV) mass, LV mass index (LVMI), and LV mass at risk were all significantly different in the three groups with the greatest values in the highest tertile group (all, P < 0.05). On multivariable analysis, male gender, NT-proBNP, and PCATA were independent predictors of LVMI. Culprit vessel PCATA was significantly associated with LVMI, but not with regional physiology in CAD patients with functionally significant lesions and preserved systolic function. Our results may offer insight into the pathophysiological mechanisms linking pericoronary inflammation and LVH to worse prognosis.

Optical coherence tomography-defined plaque vulnerability in relation to functional stenosis severity stratified by fractional flow reserve and quantitative flow ratio.

OBJECTIVES: We sought to investigate that the quantitative flow ratio (QFR) might be associated with optical coherence tomography (OCT)-defined plaque vulnerability. BACKGROUND: Both functional stenosis severity and plaque instability are related to adverse clinical outcomes in patients with coronary artery disease. Recent studies have shown an association between physiological stenosis severity and the presence of thin-cap fibroatheroma (TCFA). Measurement of QFR is a novel method for rapid computational estimation of fractional flow reserve (FFR). METHODS: We investigated 327 de novo intermediate-to-severe coronary lesions in 295 stable patients who underwent OCT, FFR, and QFR computation. The lesions were divided into tertiles based on either the FFR or QFR. The OCT findings were compared among these tertiles of FFR and QFR. Each tertile was defined as follows: FFR-T1 (FFR < 0.72), FFR-T2 (0.72 ≤ FFR ≤ 0.79), and FFR-T3 (FFR > 0.79) and QFR-T1 (QFR < 0.73), QFR-T2 (0.73 ≤ QFR ≤ 0.78), and QFR-T3 (QFR > 0.78). RESULTS: The prevalence of OCT-defined TCFA showed graded differences in proportion to the QFR tertiles (25.0% vs. 12.8% vs. 6.6%, p = .003). An overall significant difference in the prevalence of TCFA was found among FFR tertiles (p = .048), although pairwise comparison did not show statistical significance. Compared with FFR-based classifications, the model that integrated the FFR and QFR categorization improved the incremental reclassification efficacy (relative integrated discrimination improvement, 0.069; p = .002; continuous net reclassification improvement, 0.356; p = .022) for predicting the presence of TCFA. CONCLUSIONS: OCT-defined plaque instability was associated with the QFR in angiographically intermediate-to-severe lesions. Compared with the FFR alone, the QFR can provide incremental efficacy in predicting the presence of TCFA.

Clinical significance of the presence of puff-chandelier ruptures detected by nonobstructive aortic angioscopy.

OBJECTIVE: This study aimed to investigate the prevalence and prognostic significance of atherosclerotic aortic plaques (AAPs) or specific AAP types detected by nonobstructive angioscopy (NOA) in patients who underwent percutaneous coronary intervention (PCI). BACKGROUND: Although recent studies have reported the presence of various patterns of AAPs, identified by NOA, the clinical significance of the presence of AAPs remains elusive. METHODS: In this retrospective, multicenter cohort study, a total of 167 patients who underwent PCI and intra-aortic scans with NOA were studied. The association between AAPs and the incidence of major adverse cardiac events (MACEs), including cardiac death, myocardial infarction, stroke, and clinically driven unplanned revascularizations, was assessed. RESULTS: AAPs were detected in 126 patients (75%) who underwent NOA. MACEs occurred in 28 (17%) patients during the follow-up (median 2.9 years [range 2.1-3.8]). Among all types of AAPs, only puff-chandelier rupture (PCR) showed a significant difference in frequency between patients with and those without MACEs: 21 (75%) and 49 (35%), respectively (p < .001). Multivariable Cox proportional hazard analysis revealed that PCR (hazard ratio [HR] 3.73, 95% confidence interval [CI] 1.57-8.87, p = .004) and chronic kidney disease (HR 2.97, 95% CI 1.37-6.44, p = .010) were independent predictors of MACEs. Kaplan-Meier analysis revealed that PCR was significantly associated with more frequent MACEs. CONCLUSION: The detection of PCR in the aorta using NOA was significantly associated with an increased risk of subsequent adverse events after PCI.

All Resting Physiological Indices May Not Be Equivalent　- Comparison Between the Diastolic Pressure Ratio and Resting Full-Cycle Ratio.

BACKGROUND: Differences between resting full-cycle ratio (RFR) and diastolic pressure ratio (dPR) have not been sufficiently discussed. This study aimed to investigate if there is a difference in diagnostic performance between RFR and dPR for the functional lesion assessment and to assess if there are specific characteristics for discordant revascularization decision-makings between RFR and dPR.Methods and Results:A total of 936 intermediate lesions in 776 patients who underwent measurements of fractional flow reserve (FFR), coronary flow reserve (CFR), and the index of microcirculatory resistance (IMR) were retrospectively studied. Physiological indices were measured from anonymized pressure recordings at an independent core laboratory. Both RFR and dPR measures were highly correlated (r=0.997, P<0.001), with equivalent diagnostic performance relative to FFR-based decision-makings measured by using a dichotomous threshold of 0.80 (accuracy, 79.7% vs. 80.1%, respectively, P=0.960). The rate of diagnostic discordance was 4.7% (44/936), with no RFR-/dPR+ lesions observed. An overall significant difference in FFR and CFR values were detected among RFR/dPR-based classifications. The prevalence of positive studies was significantly higher for RFR than dPR (54.3% vs. 49.6%, respectively, P=0.047) when using the cut-off value of 0.89. CONCLUSIONS: Both RFR and dPR were highly correlated, but the prevalence of positive studies was significantly different. The revascularization rate may differ significantly according to the resting index used.

Ventricular Fibrillation During Optical Coherence Tomography/Optical Frequency Domain Imaging　- A Large Single-Center Experience.

BACKGROUND: The risks of ventricular fibrillation (Vfib) associated with frequency-domain optical coherence tomography (OCT)/optical frequency domain imaging (OFDI) remain undetermined.Methods and Results:We retrospectively studied the occurrence of Vfib during OCT/OFDI for unselected indications. The frequency of Vfib and patient and procedural characteristics were investigated. A total of 4,467 OCT/OFDI pullback examinations were performed in 1,754 patients (median of 2.0 [2.0-3.0] pullbacks for 1.0 [1.0-1.3] vessels). OCT/OFDI was performed during PCI in 899 patients (51.3%). The contrast injection volume per pullback was 14.4 (11.7-17.2) mL with a flow rate of 3.4 (3.2-3.5) mL/s. Vfib occurred in 31 pullbacks (0.69%) in 30 patients (1.7%). No cases of Vfib occurred when using low-molecular-weight dextran. On multivariate analysis, contrast volume was the only independent factor for predicting Vfib (odds ratio, 1.080; 95% confidence interval, 1.008-1.158, P=0.029). The best cutoff value of contrast volume for predicting Vfib was 19.2 mL (area under the curve, 0.713, P<0.001; diagnostic accuracy, 87.1%). CONCLUSIONS: The present large, single-center registry study indicated that Vfib during OCT/OFDI was rare for unselected indications. Contrast injection volume used to displace blood should be limited to avoid Vfib.

Prognostic implication of global myocardial blood flow in patients with ST-segment elevation myocardial infarction.

The prognostic implications of cardiovascular magnetic resonance imaging (CMR)-derived hyperemic myocardial blood flow (MBF) in patients with ST-elevation myocardial infarction (STEMI) are unknown. This study sought to investigate the incremental prognostic value of hyperemic MBF over conventional CMR markers to identify patients with high risk of future incidence of patient-oriented composite outcomes (POCO) and major adverse cardiac events (MACE) after STEMI. A total of 237 patients who presented with STEMI were prospectively enrolled. The CMR protocol included left-ventricular ejection fraction (LVEF), late gadolinium enhancement (LGE) and microvascular obstruction (MVO) measurement, and volumetric MBF assessment. During a median follow-up of 2.6 years, 47 patients experienced POCO (primary outcome) and 21 patients had MACE. In a multivariable model, multivessel disease, LGE, MVO, and hyperemic MBF were independently associated with POCO. Addition of hyperemic MBF to the model consisting of GRACE score, multivessel disease, LVEF, LGE, and MVO significantly improved the predictive efficacy (integrated discrimination improvement 0.020, p = 0.021). Patients with low hyperemic MBF had significantly higher incidence of MACE compared to those with high hyperemic MBF in propensity score matching analysis (p = 0.018). In conclusion, CMR-derived hyperemic MBF could provide independent and incremental prognostic value over LVEF, LGE, and MVO in patients with STEMI.

Prognostic Value of Phase-Contrast Cine-Magnetic Resonance Imaging-Derived Global Coronary Flow Reserve in Patients With Non-ST-Segment Elevation Acute Coronary Syndrome Treated With Urgent Percutaneous Coronary Intervention.

BACKGROUND: Phase-contrast cine-magnetic resonance imaging (PC-CMR) of the coronary sinus (CS) is a promising approach for quantifying coronary sinus flow (CSF) and global coronary flow reserve (G-CFR). We evaluated the prognostic value of G-CFR using PC-CMR in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS).Methods and Results:The study prospectively enrolled 116 NSTE-ACS patients who underwent uncomplicated urgent PCI within 48 h of symptom onset. Post-PCI (median, 20 days) PC-CMR images of the CS were acquired to assess absolute CSF at rest and during maximum hyperemia. The association of G-CFR with major adverse cardiac events (cardiac death, nonfatal myocardial infarction, late revascularization, or hospitalization for congestive heart failure) was investigated. Rest and maximal hyperemic CSF and corrected G-CFR were 1.27 [interquartile range, 0.79-1.73] mL/min/g, 2.95 [2.02-3.84] mL/min/g, and 2.42 [1.69-3.34], respectively. At a median follow-up of 17 months, cardiac event-free survival was significantly worse in patients with a corrected G-CFR <2.33 (log-rank χ2=19.5, P<0.001). Cox proportional-hazards analysis showed that corrected G-CFR (hazard ratio, 0.434, 95% CI, 0.270-0.699, P<0.001) and NT-pro BNP at admission (hazard ratio, 1.0001, 95% CI, 1.0000-1.0001, P=0.007) were independent predictors of adverse cardiac events during follow-up. CONCLUSIONS: In NSTE-ACS patients successfully revascularized within 48 h of onset, post-PCI PC-CMR-derived G-CFR provided significant prognostic information independent of infarct size and conventional risk scores.

Interrelationship in the prognostic efficacy of regional coronary flow reserve, fractional flow reserve, high-sensitivity cardiac troponin-I and NT-proBNP in patients with stable coronary artery disease.

This study aimed to investigate the combined efficacy in prediction of major adverse cardiac events (MACE) by coronary regional physiological indices including coronary flow reserve (CFR) or fractional flow reserve (FFR) and high-sensitivity cardiac troponin-I (hs-cTnI) or N-terminal pro brain natriuretic peptide (NT-proBNP). Impaired CFR, decreased FFR, elevated cardiac troponin, and NT-proBNP are all associated with increased MACE, while these interaction or collinearity remains uncertain. The study included 429 patients with stable coronary artery disease (CAD) evaluated hs-cTnI and NT-proBNP levels before regional physiological measurement during coronary angiography. Patients were followed up for MACE including all-cause death, myocardial infarction, hospital admission for heart failure and target vessel remote revascularization. Median hs-cTnI and NT-proBNP values were 4 ng/L and 85 ng/L, respectively. Regional CFR was significantly albeit weakly correlated with hs-cTnI and NT-proBNP, while fractional flow reserve (FFR) was only linked to hs-cTnI. The addition of hs-cTnI and NT-proBNP on clinical backgrounds and angiographic score significantly improved predictive accuracy for MACE incidence, and further consideration of FFR and CFR could refine the model. The combined stratification using hs-cTnI, NT-proBNP, FFR and CFR could efficiently stratify patient risk for MACE. In patients with stable CAD, integrated assessment of cardiac biomarkers and physiological indices could be useful for predicting future cardiovascular events.

High-sensitivity cardiac troponin decrease after percutaneous coronary intervention in patients with stable coronary artery disease.

Baseline cardiac troponin is a strong predictor of major adverse cardiac events (MACE), and the high sensitive assay can provide risk stratification under the 99th percentile values. Currently, prognostic benefit of PCI has not been established in patients with stable coronary artery disease (CAD), and the influence on baseline troponin levels is unknown. This study aimed to investigate the impact of PCI on baseline high-sensitivity cardiac troponin-I (hs-cTnI) levels and the association with MACE incidence. For 401 patients with stable CAD who were indicated for PCI, baseline hs-cTnI levels were measured before PCI for two times (the average: pre-PCI hs-cTnI) and 10 months after PCI (post-PCI remote hs-cTnI). Hs-cTnI day-to-day variability was assessed based on the pre-PCI values and patients were divided into three groups (Increase/No change/Decrease group) according to the extent of hs-cTnI change (post-PCI remote hs-cTnI minus pre-PCI hs-cTnI) considering the day-to-day variability. A total of 77 patients were categorized into Decrease group. Although Decrease group had significantly higher pre-PCI hs-cTnI levels compared to the other groups, this group had lowest incidence of MACE (p < 0.001). Hs-cTnI changes were independently associated with MACE incidence after adjustment (HR 2.069, 95% CI 1.032-4.006, p = 0.041 for Increase group vs. No change group; HR 0.143, 95% CI 0.008-0.680, p = 0.009 for Decrease group vs. No change group). Hs-cTnI change following PCI was significantly predicted by pre-PCI hs-cTnI, hs-cTnI variability, the presence of dyslipidemia, multivessel disease, and lesions with chronic total occlusion or low quantitative flow ratio. In conclusion, PCI could lower hs-cTnI levels in a certain subset of patients, in whom prognostic benefit might be expected by the intervention.

Impact of Transradial Catheterization on Vascular Function of the Brachial Artery Assessed by Flow-Mediated Dilatation.

BACKGROUND: Few studies have evaluated long-term vascular function after radial access catheterization. Furthermore, the impact of repeated catheterization remains unknown. We investigated flow-mediated dilatation (FMD) of the brachial artery after transradial catheterization. METHODS: We prospectively enrolled 50 patients with suspected coronary artery disease referred for diagnostic coronary angiography. No ad-hoc percutaneous coronary interventions (PCI) had been performed at the time of the index procedure. In 30 patients (63.8%), PCI and/or repeated follow-up diagnostic catheterization were subsequently performed via the radial artery used at the index catheterization. FMD was successfully measured before catheterization, at 24 h after catheterization, and after long-term follow-up (mean, 32 months; range, 24-43) in 47 patients. FMD at follow-up was compared between patients receiving only one procedure and those receiving multiple procedures via the same arteries. RESULTS: FMD was significantly decreased after catheterization and recovered well in long-term follow-up (3.7 ± 1.6%, 3.0 ± 1.7%, and 3.9 ± 1.6%). There was no significant difference in follow-up FMD between the patients undergoing single catheterization and those with multiple procedures (3.4 ± 1.3 vs. 4.3 ± 1.7, p = 0.06). When the patients were divided into two groups according to the median follow-up FMD value, no significant predictive factor was identified for worse FMD. CONCLUSIONS: After transradial catheterization, FMD of the brachial artery temporarily decreased but recovered in long-term follow-up. Recovery of FMD was not jeopardized by repeated catheterization, which suggests the potential of the brachial artery to recover endothelial function after repeated transradial procedures.

Prognostic value of the index of microcirculatory resistance after percutaneous coronary intervention in patients with non-ST-segment elevation acute coronary syndrome.

BACKGROUND: The prognostic value of physiological indices in non-ST-segment elevation acute coronary syndrome (NSTE-ACS) patients undergoing percutaneous coronary intervention (PCI) is unknown. We investigated the prognostic efficacy of physiological indices obtained after PCI in patients with NSTE-ACS. METHODS: Eighty-three patients (men: n = 70, age: 63.7 ± 9.7 years) undergoing PCI for NSTE-ACS within 48 hr postadmission were investigated. Fractional flow reserve (FFR), coronary flow reserve (CFR), and the index of microcirculatory resistance (IMR) of the culprit vessels were measured after the completion of PCI. The patients were clinically followed up to determine major cardiac adverse events (MACE), including death, congestive heart failure requiring hospitalization, and remote coronary revascularization. RESULTS: The median FFR, CFR, and IMR values were 0.90 (interquartile range [IQR] 0.86-0.95), 2.38 (IQR 1.75-4.17), and 22.9 (IQR 11.2-31.5), respectively. During a median follow-up of 20.7 months, 19 MACEs (22.9%) were documented. No significant difference in baseline patient characteristics, except for age, was detected between patients with and without MACE. Patients with MACE showed higher IMR and lower CFR than those without (IMR: 27.2 vs. 16.3; P = 0.001, CFR: 1.82 vs. 2.55; P = 0.04), whereas FFR was not significantly different (0.92 vs. 0.89; P = 0.72), irrespective of the MACE occurrence. Post-PCI IMR was the only independent predictor of MACE (hazard ratio 1.033, 95% confidence interval 1.013-1.052, P = 0.001). The MACE-free survival was significantly worse in patients with high post-PCI IMR (χ2 7.12; P = 0.008). CONCLUSION: Post-PCI IMR may help identify patients at high risk for subsequent adverse coronary events who require adjunctive therapeutic strategies.

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.

OBJECTIVES: 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). BACKGROUND: Decision making for revascularization when FFR is 0.75-0.80 is controversial. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

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

BACKGROUND: Few studies have documented changes in myocardial blood flow (MBF) after percutaneous coronary intervention (PCI). Phase-contrast cine cardiovascular MRI (PC-CCMR) of the coronary sinus (CS) is a promising approach to quantify MBF. The aim of this study was to quantify CS flow (CSF) on PC-CCMR as a measure of volumetric MBF before and after elective PCI.Methods and Results:We prospectively studied 34 patients with stable angina undergoing elective PCI for a single de novo lesion. Breath-hold PC-CCMR of CS was acquired to assess CSF and coronary flow reserve (CFR) at rest and during maximum hyperemia both before and after PCI (median, 3 days before PCI and 10 days after PCI, respectively). In total, hyperemic CSF increased significantly after PCI (before PCI, median, 2.3 mL/min/g [IQR, 1.5-3.2 mL/min/g] after PCI, 3.0 [1.8-3.7] mL/min/g), although 13 patients (38.2%) had a decrease despite successful PCI and fractional flow reserve (FFR) improvement. Global CFR also significantly increased from a median of 2.5 (IQR, 1.5-3.5) to 3.4 (IQR, 2.1-4.2), whereas 12 patients had decreased CFR after PCI. Pre-PCI hyperemic CSF was the only independent factor of change in CSF following PCI. CONCLUSIONS: Serial PC-CCMR of CS as a measure of change in absolute MBF is feasible. Uncomplicated PCI does not necessarily increase hyperemic global MBF, despite regional FFR improvement.

Influence of visual-functional mismatch on coronary flow profiles after percutaneous coronary intervention: a propensity score-matched analysis.

The aims of this study are to clarify whether discrepancies between angiographic and fractional flow reserve (FFR) measurements (visual-functional mismatch) influence coronary flow profiles after percutaneous coronary intervention. While current guidelines FFR-guided revascularization, clinical practice most commonly relies on angiographic evaluation, which may under- or over-estimate the functional relevance of the lesion. Our retrospective analysis involved 274 vessels from 264 patients with stable angina pectoris who underwent FFR, index of microvascular resistance, and coronary flow reserve (CFR) measurements before and after PCI. Visual-functional concordance and discordance (reverse mismatch) were defined as angiographic stenosis > 50% with FFR ≤ 0.80 and angiographic stenosis ≤ 50% with FFR ≤ 0.80, respectively. Propensity score-matched cohort included 132 lesions (66 lesions: concordant findings, 66 lesions: reverse mismatch). The change in coronary flow profiles after PCI was assessed in terms of FFR, CFR, index of microvascular resistance (IMR), and mean transit time (Tmn). Compared with concordant territories, reverse mismatch territories were associated with lower pre-PCI IMR, higher pre-PCI CFR, greater minimum lumen diameter and smaller reference diameter (all comparisons, P < 0.05). After propensity score matching, the prevalence and extent of coronary flow improvement after PCI, evaluated by CFR and Tmn, were both remained significantly greater in concordant territories (all comparisons, P < 0.05). The prevalence and extent of coronary flow improvement after PCI assessed by the physiologic indices was significantly greater in visual-functional concordant lesions, suggesting that these coronary physiologic changes were associated with discrepancy between angiographic measurements.