Difference in radiofrequency ablation profile between during sinus rhythm and atrial fibrillation: Considerations in this era of high-power short-duration strategy.

Background: The concept of ablation index (AI) was introduced to evaluate radiofrequency (RF) ablation lesions. It is calculated from power, contact force (CF), and RF duration. However, other factors may also affect the quality of ablation lesions. To examine the difference in RF lesions made during sinus rhythm (SR) and atrial fibrillation (AF). Methods: Sixty patients underwent index pulmonary vein isolation during SR (n = 30, SR group) or AF (n = 30, AF group). All ablations were performed with a power of 50 W, a targeted CF of 5-15 g, and AI of 400-450 using Thermocool Smarttouch SF. The CF, AI, RF duration, temperature rise (Δtemp), impedance drop (Δimp), and the CF stability of each ablation point quantified as the standard deviation of the CF (CF-SD) were compared between the two groups. Results: A total of 3579 ablation points were analyzed, which included 1618 and 1961 points in the SR and the AF groups, respectively. Power, average CF, RF duration per point, and the resultant AI (389 ± 59 vs. 388 ± 57) were similar for the two rhythms. However, differences were seen in the CF-SD (3.5 ± 2.2 vs. 3.8 ± 2.1 g, p < .01), Δtemp (3.8 ± 1.3 vs. 4.0 ± 1.3°C, p < .005), and Δimp (10.3 ± 5.8 vs. 9.4 ± 5.4 Ω, p < .005). Conclusions: Despite similar AI, various RF parameters differed according to the underlying atrial rhythm. Ablation delivered during SR demonstrated less CF variability and temperature increase and greater impedance drop than during AF.

A Single Atrial Extrastimulation Resetting His Bundle During Supraventricular Tachycardia to Differentiate Atrial Tachycardia.

BACKGROUND: Catheter ablation is the curative treatment for paroxysmal supraventricular tachycardia (SVT). However, atrial tachycardia (AT) diagnosis is often challenging, especially when SVT is terminated by pacing. OBJECTIVES: This study sought to develop a novel method for AT diagnosis. METHODS: A total of 147 SVTs including 28 ATs, 87 atrioventricular nodal re-entrant tachycardias, and 32 orthodromic reciprocating tachycardias were prospectively studied. Single atrial extrastimulation was performed at the proximal coronary sinus from a coupling interval 20 milliseconds shorter than the tachycardia cycle length and gradually decreased until the His bundle (HB) was first reset and further until the SVT was terminated. The response of the SVT during the first HB resetting and the termination pattern were examined. RESULTS: In 27 of 28 ATs, tachycardia was unaffected when HB resetting whereas, in atrioventricular nodal re-entrant tachycardias or orthodromic reciprocating tachycardias (non-AT), tachycardia was simultaneously reset when HB resetting or was terminated with an atrio-Hisian block. When the coupling interval was further shortened for cases in which tachycardia persisted, all 33 SVTs with tachycardia termination with atrio-Hisian block were non-ATs, whereas 5 ATs and 7 non-ATs were terminated with Hisian-atrial block. The sensitivity, specificity, and positive and negative predictive values of the pattern of tachycardia that was unaffected when HB resetting for AT diagnosis were 96%, 100%, 100%, and 99%, respectively. Those of the pattern of tachycardia termination with atrio-Hisian block for non-AT diagnosis were 92%, 100%, 100%, and 42%, respectively. CONCLUSIONS: Single atrial extrastimulation from the proximal coronary sinus during tachycardia was useful and effective for AT diagnosis.

Features Suggesting Preferential Conduction in Pulmonary Artery Ventricular Arrhythmia for Identification of Successful Ablation Sites.

Radiofrequency catheter ablation (RFCA) for pulmonary artery ventricular arrhythmia (PAVA) can be difficult because of the occasional existence of PAVA with preferential conduction.This study described the characteristics of PAVA that demonstrate preferential conduction.We analyzed electrocardiographic and electrophysiological data from 8 patients found to have PAVAs with preferential conduction out of 183 patients (4.4%) with right ventricular outflow tract (RVOT) arrhythmias who underwent RFCA at our hospitals. The PAVA with preferential conduction were classified into two types. In type 1 PAVA, successful ablation sites (success-sites) exhibited discrete prepotentials with an isoelectric line, in which the activation time (AT) was ≥ 50 milliseconds. In type 2 PAVA, excellent pace mapping was achieved at two sites separated by ≥ 20 mm: one in the RVOT free wall and the other at the success-site in the pulmonary artery. Type 1 and 2 PAVA features were considered signs of a short and long preferential conduction pathway, respectively.There were four patients each with type 1 and 2 PAVA. Type 1 PAVA was distinguished by the isoelectric line at success-sites with the mean AT of 78 ± 25.1 milliseconds. In type 2 PAVAs, although the AT at RVOT sites was very short (18.5 ± 10.1 milliseconds), the AT at success-sites was longer than that at the RVOT by 42.3 ± 36.2 milliseconds. Type 2 PAVAs displayed distinct electrocardiogram (ECG) features (R wave in lead I, RR' in inferior leads, and transitional zone in V4) not found in typical PAVA ECGs.PAVA with preferential conduction can manifest in distinct ways on the ECG and intracardiac mapping. Knowledge of these features may facilitate successful RFCA of such PAVA cases.

Individualized left anterior oblique projection based on pigtail catheter visualization facilitates leadless pacemaker implantation.

BACKGROUND: Pacemaker positioning on the right ventricular (RV) septum during implantation is conventionally conducted utilizing two fixed fluoroscopy angles, a 45° left anterior oblique (LAO) and 35° right anterior oblique projection. However, placement location can be suboptimal, especially for leadless pacemakers (LPMs). OBJECTIVE: To evaluate the safety and ease of LPM implantation using individualized LAO projection. METHODS: Consecutive patients undergoing LPM implantation were prospectively included. The angle of the RV septum was recorded for each patient by studying the angle at which an RV pigtail catheter (RV-PC) could be seen edge on. This was then used as the preferred LAO projection angle for that patient. We evaluated the success rate and safety of this method. We also compared the RV septum angle as measured by this method versus that measured by chest CT. RESULTS: Of the 31 patients (mean age 80.6 ± 7.0 years, 15 females), LPM implantation was successful in 30. The pacemaker was implanted on the RV septum in 29 and on the free wall in one. LPM implantation was abandoned for anatomical reasons in one. Complications were limited to a groin arteriovenous fistula and one deep vein thrombosis. The angle of RV septum as measured by pigtail catheter and chest CT was not significantly different (CT: 54.8 ± 6.0°, RV pigtail catheter: 52.9 ± 6.1°, P = .07). CONCLUSIONS: Using an RV-PC to determine the preferred angle of LAO projection facilitates differentiation between the RV septum and free wall, which in turn facilitates optimal LPM placement.

Superior vena cava isolation with 50 W high power, short duration ablation strategy.

INTRODUCTION: The optimal ablation strategy is unknown regarding a superior vena cava isolation (SVCI). This study aimed to examine the feasibility and safety and to analyze the lesion characteristics of the SVCI using high-power, short-duration (HPSD) ablation. METHODS AND RESULTS: A total of 100 patients underwent an index SVCI using HPSD (n = 50, HPSD group) or conventional lower-power and longer-duration (n = 50, LPLD group) ablation, using the Thermocool Smarttouch SF. In the HPSD group, ablation was performed with a power of 50 W for 7 s, and was limited to 4 s at the lateral segment close to the right phrenic nerve. The ablation setting used in the LPLD group was 20-25 W for 20-30 s and was limited to 10-20 W for 15-30 s at the lateral segment when diaphragmatic capture was seen. An electrical SVCI was achieved in all patients. The HPSD group required a significantly shorter procedure time (10.8 ± 3.2 vs. 14.8 ± 6.4 min; p < .01), shorter radiofrequency duration (49 ± 16 vs. 282 ± 124 s; p < .01), fewer lesions (8.3 ± 2.5 vs. 10.4 ± 4.4; p < .01), and lower ablation index (316 ± 38 vs. 356 ± 62; p < .001) than the LPLD group. The incidence of a postprocedural asymptomatic mild diaphragmatic elevation was comparable (2% in the HPSD group vs. 6% in the LPLD group; p = .61). CONCLUSION: The 50-W HPSD ablation strategy allowed for a successful, fast, and safe SVCI with the fewer ablation lesions and the lower ablation index.

Determinants of Pericoronary Adipose Tissue Attenuation on Computed Tomography Angiography in Coronary Artery Disease.

Background Recent studies have reported the association between pericoronary inflammation assessed by pericoronary adipose tissue attenuation (PCATA) on computed tomography angiography and worse outcomes in patients with coronary artery disease. We investigated the determinants predicting increased PCATA in patients with known or suspected coronary artery disease. Methods and Results A total of 540 patients who underwent computed tomography angiography and invasive coronary angiography were studied. Mean computed tomography attenuation values of PCAT (-190 to -30 Hounsfield units) (PCATA) were assessed at the proximal 40-mm segments of all 3 major coronary arteries by crude analysis. Univariable and multivariable analyses were performed to determine the predictors of increased PCATA surrounding the proximal right coronary artery. Mean right coronary artery-PCATA was -72.22±8.47 Hounsfield units and the average of 3-vessel PCATA was -70.24±6.60 Hounsfield units. Multivariable linear regression analysis revealed that the independent determinants of right coronary artery-PCATA were male (ß coefficient=4.965, P<0.001), left ventricular mass index (ß coefficient=0.040, P=0.025), and angiographically significant stenosis (diameter stenosis >50%) (ß coefficient=2.418, P=0.008). Sex-related determinants were NT-proBNP level (N-terminal pro-B-type natriuretic peptide; ß coefficient <0.001, P=0.026), Agatston score (ß coefficient=-0.002, P=0.010), left ventricular mass index (ß coefficient=0.041, P=0.028), and significant stenosis (ß coefficient=4.006, P<0.001) in male patients and left ventricular ejection fraction (ß coefficient=-0.217, P=0.010) and significant stenosis (ß coefficient=3.835, P=0.023) in female patients. Conclusions Right coronary artery-PCATA was associated with multiple clinical characteristics, established risk factors, and the presence of significant stenosis. Our results suggest that clinically significant factors such as sex, left ventricular hypertrophy, ejection fraction, calcification, and epicardial stenosis should be taken into account in the assessment of pericoronary inflammation using computed tomography angiography.

Correction to: Anti-cyclic citrullinated peptide antibody in the cerebrospinal fluid in patients with rheumatoid arthritis who have central nervous system involvement.

The authors regret that the original published version of the above article contained errors. The authors requested that these be noted.

Anti-cyclic citrullinated peptide antibody in the cerebrospinal fluid in patients with rheumatoid arthritis who have central nervous system involvement.

Central nervous system (CNS) involvement, including encephalopathy, encephalitis, leptomeningitis, and pachymeningitis, in rheumatoid arthritis (RA) is rather rare. We report the case of a 61-year-old female with a history of RA in remission for 7 years, who presented with numbness, weakness of the left upper limb, dysarthria, and headache. Magnetic resonance imaging (MRI) of the brain showed meningeal enhancement in the frontal, parietal, and temporal lobes. Cerebrospinal fluid (CSF) examination detected high levels of both rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibody (ACPA), with a high ACPA-immunoglobulin G index (> 2.0). She was diagnosed with rheumatoid meningitis. Following combined therapy with oral prednisolone and intravenous infusion of cyclophosphamide, her symptoms promptly improved. After treatment, RF and ACPA levels in the CSF were reduced, and MRI showed improvement of the meningeal structures. This case, along with existing literature, suggests that the ACPA level in the CSF may serve as a useful marker for diagnosing of CNS involvement in RA, as well as an index of effectiveness of the associated treatment.

Functional classification discordance in intermediate coronary stenoses between fractional flow reserve and angiography-based quantitative flow ratio.

Background: Measurement of the contrast-flow quantitative flow ratio (cQFR) is a novel method for rapid computational estimation of fractional flow reserve (FFR). Discordance between FFR and cQFR has not been completely characterised. Methods: We performed a post-hoc analysis of 504 vessels with angiographically intermediate stenosis in 504 patients who underwent measurement of FFR, coronary flow reserve (CFR), the index of microcirculatory resistance (IMR) and Duke jeopardy score. Results: In total, 396 (78.6%) and 108 (21.4%) lesions showed concordant and discordant FFR and cQFR functional classifications, respectively. Among lesions with a reduced FFR (FFR+), those with a preserved cQFR (cQFR-) showed significantly lower IMR, shorter mean transit time (Tmn), shorter lesion length (all, p<0.01) and similar CFR and Duke jeopardy scores compared with lesions showing a reduced cQFR (cQFR+). Furthermore, lesions with FFR+ and cQFR- had significantly lower IMR and shorter Tmn compared with lesions showing a preserved FFR (FFR-) and cQFR+. Of note, in cQFR+ lesions, higher IMR lesions were associated with decreased diagnostic accuracy (high-IMR; 63.0% and low-IMR; 75.8%, p<0.01). In contrast, in cQFR- lesions, lower IMR lesions was associated with decreased diagnostic accuracy (high-IMR group; 96.8% and low-IMR group; 80.0%, p<0.01). Notably, in total, 31 territories (6.2%; 'jump out' group) had an FFR above the upper limit of the grey zone (>0.80) and a cQFR below the lower limit (≤0.75). In contrast, five territories (1.0%; 'jump in' group) exhibited opposite results (FFR of ≤0.75 and cQFR of >0.80). The 'jump out' territories showed significantly higher IMR values than 'jump in' territories (p<0.01). Conclusions: FFR- with cQFR+ is associated with increased microvascular resistance, and FFR+ with cQFR- showed preservation of microvascular function with high coronary flow. Microvascular function affected diagnostic performance of cQFR in relation to functional stenosis significance.

Plaque morphology assessed by optical coherence tomography in the culprit lesions of the first episode of acute myocardial infarction in patients with low low-density lipoprotein cholesterol level.

BACKGROUND: There remains a residual risk for acute myocardial infarction (AMI) even with low low-density lipoprotein cholesterol (LDL-C) levels. This study aimed to characterize the culprit lesion morphology of AMI by optical coherence tomography (OCT) in patients with low LDL-C. METHODS: Four-hundred and nine culprit lesions of 409 patients with their first presentation of AMI imaged by OCT were investigated. OCT analysis included the presence of plaque rupture and thin-capped fibroatheroma (TCFA). Fibrous cap thickness and lipid length were also measured. Intravascular ultrasound (IVUS) was performed in 368 (90.0%) patients. OCT and IVUS findings were compared between patients with LDL-C < 100 mg/dl (lower-LDL group) and those with LDL ≥ 100 mg/dl (higher-LDL group). RESULTS: Lower-LDL group included 93 (22.7%) patients. Plaque rupture (54.8% vs. 68.7%, p = 0.018) and TCFA (39.8% vs. 54.6%, p = 0.013) were less frequently observed in lower-LDL than in higher-LDL. Fibrous cap was thicker [73 (59-109) µm vs. 63 (57-83) µm, p = 0.028] and lipid length was smaller [5.4 (2.3-9.9) mm vs. 7.1 (4.1-10.5) mm, p = 0.012] in lower-LDL than in higher-LDL. There were no significant differences in IVUS parameters including plaque burden or remodeling index between the two groups. CONCLUSIONS: Patients with lower LDL-C showed more prevalent intact fibrous cap and less vulnerable features in the culprit lesions, which may suggest the need for exploring a specific strategy for the prevention of plaque erosion in low LDL-C subjects.

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.

Clinical Significance of the Presence or Absence of Lipid-Rich Plaque Underneath Intact Fibrous Cap Plaque in Acute Coronary Syndrome.

Background Although most coronary thromboses occur on the surface of lipid-rich plaque ( LRP ) with plaque rupture ( PR ), previous pathological and optical coherence tomography studies demonstrated diversity in the morphological characteristics of culprit plaque underlying the thrombus, including lesions with intact fibrous cap ( IFC ). We investigated the clinical significance of IFC in relation to the presence or absence of LRP observed via optical coherence tomography in culprit lesions of acute coronary syndrome. Methods and Results We investigated 510 patients with acute coronary syndrome who underwent optical coherence tomography for the culprit lesion. Optical coherence tomography analysis included the presence or absence of PR , which were categorized into the PR group and the IFC group, respectively. The IFC group was further categorized on the basis of the presence of LRP . Incidence of major adverse cardiac events ( MACEs ), including cardiac death, myocardial infarction, and clinically driven remote revascularizations, was compared. Culprit lesions were categorized into 328 PR s and 182 IFC s. MACEs occurred in 85 patients (16.7%) during the median follow-up duration of 621 days. LRP was detected in 325 lesions (99%) with PR , whereas 60 (33.0%) of the lesions with IFC did not show LRP . Kaplan-Meier analysis revealed significantly lower MACEs in the IFC group compared with the PR group. Furthermore, the IFC group without LRP showed significantly lower MACEs compared with the IFC group with LRP . Multivariate Cox proportional hazards analysis demonstrated that IFC without LRP was an independent predictor of better prognosis. Conclusions Exclusion of LRP underneath IFC culprit lesions in acute coronary syndrome may predict a lower risk of future MACEs .

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.

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.

Prognostic implication of three-vessel contrast-flow quantitative flow ratio in patients with stable coronary artery disease.

AIMS: Contrast-flow quantitative flow ratio (cQFR) is a novel index of the functional severity of coronary stenosis, which can be calculated from three-dimensional quantitative coronary angiography. Previous studies have shown a high correlation between cQFR and fractional flow reserve. This study sought to investigate the prognostic value of the sum of cQFR in three vessels (3V-cQFR) in patients with stable coronary artery disease (CAD). METHODS AND RESULTS: A total of 549 patients who underwent invasive coronary angiography and cQFR measurements in three vessels were analysed in the present study. Median cQFR of all cQFR-assessed vessels and 3V-cQFR of each patient were 0.94 (0.85-0.98) and 2.75 (2.62-2.87), respectively. During a median follow-up of 2.2 years, 57 patients experienced MACE. 3V-cQFR could provide prognostic information in the total cohort and among those without undergoing revascularisation as well. In a multivariate analysis, 3V-cQFR, high-sensitivity cardiac troponin-I and previous MI remained as independent predictors for MACE, and conventional angiographic scores did not. CONCLUSIONS: 3V-cQFR could discriminate the risk for MACE in patients with stable CAD. 3V-cQFR calculated from routine invasive angiograms was feasible, and the prognostic implication could be more powerful than that of conventional angiographic scores.

Optical Coherence Tomography-Defined Plaque Vulnerability in Relation to Functional Stenosis Severity and Microvascular Dysfunction.

OBJECTIVES: This study sought to investigate the relationship of unstable plaque features with physiological lesion severity and microvascular dysfunction. BACKGROUND: The functional severity of epicardial lesions and microvascular dysfunction are both related to adverse clinical outcomes. METHODS: We investigated 382 de novo intermediate and severe coronary lesions in 340 patients who underwent optical coherence tomography, fractional flow reserve (FFR), and index of microcirculatory resistance (IMR) examinations. Lesions were divided into tertiles based on either FFR or IMR values. The optical coherence tomography findings were compared among the tertiles of FFR and IMR. Each tertile was defined as follows: FFR-T1 (FFR <0.74), FFR-T2 (0.74 ≤ FFR ≤0.81), and FFR-T3 (FFR >0.81); and IMR-T1 (IMR ≥25), IMR-T2 (15 < IMR <25), and IMR-T3 (IMR ≤15). RESULTS: No significant relationship was observed between FFR and IMR. The prevalence of optical coherence tomography-defined thin-cap fibroatheroma (TCFA) was significantly greater in IMR-T1 than in IMR-T2 and IMR-T3. An overall significant difference in the prevalence of TCFAs was detected among FFR tertiles, although no pairwise comparison revealed statistical significance. The prevalence of ruptured plaque was significantly greater in IMR-T1 than in IMR-T2 and IMR-T3, although no significant difference was observed between FFR tertiles. Multivariate analysis showed that FFR and IMR were independent predictors of the prevalence of TCFAs (odds ratio: 0.036; 95% confidence interval: 0.004 to 0342; p = 0.004; and odds ratio: 1.034; 95% confidence interval: 1.014 to 1.054; p = 0.001, respectively). CONCLUSIONS: Lower FFR and higher IMR values were independent predictors of the presence of a TCFA in angiographically intermediate-to-severe stable lesions or nonculprit lesions in acute coronary syndrome.

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.

BACKGROUND: 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. METHODS AND RESULTS: 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). CONCLUSIONS: 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.

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.

Relationship between optical coherence tomography-derived morphological criteria and functional relevance as determined by fractional flow reserve.

BACKGROUND: Although several previous studies have indicated that optical coherence tomography (OCT)-derived minimal lumen area (MLA) correlates with fractional flow reserve (FFR) severity, other morphologic criteria for functionally significant coronary stenosis assessed by FFR have not been fully elucidated. This study aimed to identify OCT-based morphological predictors of physiologically significant ischemia assessed by FFR in angiographically intermediate coronary lesions. METHODS: We investigated 194 de novo intermediate coronary lesions in 178 patients with stable angina pectoris who underwent OCT imaging and FFR measurement. The lesions were divided into two groups according to an FFR threshold: ischemia group, FFR <0.75 (n=69) and non-ischemia group, FFR ≥0.75 (n=125). Clinical characteristics, angiographic, and OCT findings were compared between these two groups. Predictors of significant ischemia defined as FFR <0.75 were identified by logistic regression analyses. RESULTS: Patient age, statin use, lesion in left anterior descending artery (LAD), OCT-derived MLA, and lipid volume index (LVI) (averaged lipid arc multiplied by lipid length) were independent predictors of FFR <0.75 in multivariate logistic regression analysis. Receiver operating characteristic analysis suggested that age <64 years old, OCT-derived MLA ≤1.39mm2, and LVI ≥733 are the best cut-off values for predicting FFR <0.75. Multiple logistic regression models, including the MLA combined with the LAD location, LVI, age, and statin use, provided superior predictive efficacy for physiologically significant ischemia compared with the model that only employed MLA. CONCLUSIONS: Information on OCT-derived LVI and lesion locations facilitates better identification of coronary lesions that cause ischemia than OCT-derived MLA analysis alone.