A cost-effectiveness analysis of remote monitoring after pacemaker implantation for bradycardia in Japan.

BACKGROUND: Although remote monitoring (RM) after pacemaker implantation is common, its cost-effectiveness has not been fully investigated. Therefore, we assessed the cost-effectiveness of RM compared with conventional follow-up (CFU) in Japanese patients with pacemakers. METHODS: A Markov model was constructed to analyze costs and quality-adjusted life years after pacemaker implantation. The target population was Japanese patients implanted with a dual-chamber pacemaker for bradycardia. Transition probabilities (e.g. atrial fibrillation, stroke, and device trouble) were obtained from literature and expert sources. Additionally, stroke risk was determined according to anticoagulation and CHADS2 scores. We used a 10-year horizon with sensitivity analyses for significant variables. RESULTS: Compared to CFU, RM was more effective; however, it was also more expensive. When the range of the Japanese willingness-to-pay threshold was considered to be ¥5,000,000, RM was at least cost-neutral relative to the CFU in all elderly patients with pacemakers for bradycardia. The cost-effectiveness of RM relative to CFU could be higher for patients with high CHADS2 scores, especially in patients with a CHADS2 score ≥ 3. Scenario analyses changing the interval between visits to an in-office evaluation in the CFU also demonstrated the same conclusions. In particular, when the interval between office visits was 1 year for the CFU, the RM could be more cost-effective. CONCLUSIONS: This study demonstrated that RM can be a cost-effective option for Japanese patients, especially those with high CHADS2 scores and long-term intervals between office visits.

Automated categorization of virtual reality studies in cardiology based on the device usage: a bibliometric analysis (2010-2022).

Aims: Currently, virtual reality (VR) constitutes a vital aspect of digital health, necessitating an overview of study trends. We classified type A studies as those in which health care providers utilized VR devices and type B studies as those in which patients employed the devices. This study aimed to analyse the characteristics of each type of studies using natural language processing (NLP) methods. Methods and results: Literature related to VR in cardiovascular research was searched in PubMed between 2010 and 2022. The characteristics of studies were analysed based on their classification as type A or type B. Abstracts of the studies were used as corpus for text mining. A binary logistic regression model was trained to automatically categorize the abstracts into the two study types. Classification performance was evaluated by accuracy, precision, recall, F-1 score, and c-statistics of the receiver operator curve (ROC) analysis. In total, 171 articles met the inclusion criteria, where 120 (70.2%) were type A studies and 51 (29.8%) were type B studies. Type A studies had a higher proportion of case reports than type B studies (18.3% vs. 3.9%, P = 0.01). As for abstract classification, the binary logistic regression model yielded 88% accuracy and an area under the ROC of 0.98. The words 'training', '3d', and 'simulation' were the most powerful determinants of type A studies, while the words 'patients', 'anxiety', and 'rehabilitation' were more indicative for type B studies. Conclusions: NLP methods revealed the characteristics of the two types of VR-related research in cardiology.

Intravascular Imaging-Based Physiologic Assessment.

Intravascular imaging (IVI), including intravascular ultrasound (IVUS) and optical coherence tomography (OCT), is clinically useful for assessing the luminal size, lesion length, and plaque characteristics, as well as for evaluating stent deployment; however, it is not designed to estimate myocardial ischemia accurately. Thus, several types of IVI-derived fractional flow reserve (FFR) (IVI-derived FFR) have been developed and reported. In general, the algorithms of virtual FFR are based on basic fluid dynamics equations (mainly Poiseuille and Borda-Carnot equations) and original microvascular models (fixed velocity or calculating coronary flow reserve). Although the models and assumptions used in the past reports were mostly based on the standard population (not independent patient data), the developed software calculated FFR with high accuracy (88% to 94%) with strong correlations between IVI-derived FFR and wire-based FFR (0.69 to 0.89). Given several other less invasive virtual FFR methods currently available for clinical use, IVI-derived FFR would be limited for the sole use of pre-percutaneous coronary intervention (PCI) physiological evaluation; however, it may play a unique role at PCI guidance and optimization, potentially allowing comprehensive and time/cost-saving assessment of both anatomical and physiological lesion properties using a single diagnostic device.

Potential relationship between high wall shear stress and plaque rupture causing acute coronary syndrome.

The relationship between high wall shear stress (WSS) and plaque rupture (PR) in longitudinal and circumferential locations remains uncertain. Overall, 100 acute coronary syndrome patients whose culprit lesions had PR, documented by optical coherence tomography (OCT), were enrolled. Lesion-specific three-dimensional coronary artery models were created using OCT data. WSS was computed with computational fluid dynamics analysis. PR was classified into upstream-PR, minimum lumen area-PR, and downstream-PR according to the PR's longitudinal location, and into central-PR and lateral-PR according to the disrupted fibrous cap circumferential location. In the longitudinal 3-mm segmental analysis, multivariate analysis demonstrated that higher WSS in the upstream segment was independently associated with upstream-PR, and thinner fibrous cap was independently associated with downstream-PR. In the PR cross-sections, the PR region had a significantly higher average WSS than non-PR region. In the cross-sectional analysis, the in-lesion peak WSS was frequently observed in the lateral (66.7%) and central regions (70%) in lateral-PR and central-PR, respectively. Multivariate analysis demonstrated that the presence of in-lesion peak WSS at the lateral region, thinner broken fibrous cap, and larger lumen area were independently associated with lateral-PR, while the presence of in-lesion peak WSS at the central region and thicker broken fibrous cap were independently associated with central-PR. In conclusion, OCT-based WSS simulation revealed that high WSS might be related to the longitudinal and circumferential locations of PR.

Premature atrial contraction immediately after catheter ablation was associated with late recurrence of atrial fibrillation.

BACKGROUND: Although premature atrial contractions (PACs) just after catheter ablation (CA) for atrial fibrillation (AF) are common, their clinical significance is uncertain. This study aimed to evaluate whether the PAC burden after an initial CA for AF was associated with late recurrence. METHODS: We enrolled 346 patients with AF (median age, 65 years; 30% female; 57% with paroxysmal AF) who underwent an initial radiofrequency CA and a 24-h Holter monitoring the day after the procedure. PAC was defined as supraventricular complexes occurring ≥30% earlier than expected compared with a previous RR interval, and the number of PAC/24 h during post-procedural Holter monitoring was analyzed. RESULTS: AF recurred in 106 patients (31%) during a median follow-up of 19 months. These patients had significantly more PAC/24 h than those without (median [interquartile range], 891 [316-4351] beats vs. 409 [162-1,303] beats; p < 0.01). The number of PACs was independently associated with AF recurrence after adjustment for clinical parameters and left atrial (LA) enlargement. Receiver operating characteristic (ROC) curve analysis revealed that 1431 PAC/24 h was the optimal cut-off value for predicting AF recurrence. Adding the PAC/24 h to the prediction model with LA diameter appeared to correctly reclassify patients who were thought to be at high risk for AF recurrence into the low-risk group and vice versa. CONCLUSIONS: The number of PACs was an independent risk factor for AF recurrence. A 24-h Holter recording the day after an initial CA is a simple and beneficial tool for the risk stratification of AF recurrence.

Impact of Intravascular Ultrasound-Derived Lesion-Specific Virtual Fractional Flow Reserve Predicts 3-Year Outcomes of Untreated Nonculprit Lesions: The PROSPECT Study.

BACKGROUND: Hemodynamic assessment of untreated nonculprit lesions was not studied in the PROSPECT study (Providing Regional Observations to Study Predictors of Events in the Coronary Tree). We developed a virtual intravascular ultrasound-derived lesion-specific fractional flow reserve (lesion-specific IVUS-FFR) algorithm to assess individual lesion-level FFR. We sought to investigate the relation between lesion-specific IVUS-FFR and major adverse cardiovascular events (MACE) arising from untreated nonculprit lesions in the PROSPECT study. METHODS: In PROSPECT, 697 patients with acute coronary syndromes underwent 3-vessel grayscale and virtual histology-IVUS to correlate untreated nonculprit plaque morphology with 3-year nonculprit related MACE (composite of cardiac death, cardiac arrest, myocardial infarction, or rehospitalization due to unstable or progressive angina). Lesion-specific IVUS-FFR was calculated from volumetric IVUS lumen area measurements at 0.4 mm intervals by applying a mathematical circulation model using basic fluid dynamics equations. RESULTS: Lesion-specific IVUS-FFR was analyzable in 3227 nonculprit lesions in 660 patients among whom 54 nonculprit MACE events (3 myocardial infarctions) occurred at median 3.4-year follow-up. By receiver-operating characteristic analysis, the best cutoff value of lesion-specific IVUS-FFR to predict nonculprit MACE was ≤0.95. After adjusting for patient and lesion characteristics, lesion-specific IVUS-FFR (hazard ratio, 4.83 [95% CI, 2.20-10.61]; P<0.001) was an independent predictor of 3-year nonculprit MACE, in addition to minimum lumen area≤4.0 mm2, plaque burden ≥70%, and virtual histology thin-cap fibroatheroma. CONCLUSIONS: Minor reductions in lesion-specific IVUS-FFR were independently associated with future nonculprit MACE arising from untreated angiographically mild stenoses along with previously established high-risk lesion morphological characteristics. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT00180466.

Impact of Nonobstructive Left Main Coronary Artery Atherosclerosis on Long-Term Mortality.

BACKGROUND: Although the presence of severe stenosis in the left main coronary artery (LMCA) is a well-established predictor of mortality, whether this extends to nonobstructive atherosclerosis in the LMCA is unknown. OBJECTIVES: The aim of this study was to evaluate the association between LMCA disease by intravascular ultrasound (IVUS) and long-term mortality. METHODS: Between 2005 and 2013, 3,239 patients with LMCA IVUS imaging without LMCA revascularization (either before angiography or scheduled based on index angiography or IVUS) were included. The primary and secondary endpoints were all-cause and cardiac mortality at a minimum of 5 years obtained from the National Death Index. RESULTS: The IVUS-measured LMCA minimum lumen area (MLA) and plaque burden were 13.1 ± 5.0 mm2 and 41.7% ± 15.6%, respectively. The median follow-up was 8.2 years. The Kaplan-Meier estimated 12-year all-cause and cardiac death rates were 37.5% and 17.0%, respectively. Greater plaque burden (unadjusted HR per 10%: 1.17; 95% CI: 1.12-1.22; P < 0.0001) and smaller IVUS MLA (unadjusted HR per 1 mm2: 0.98; 95% CI: 0.96-0.99; P = 0.0008) were associated with all-cause death. After adjusting for clinical, angiographic, and IVUS factors, plaque burden (adjusted HR per 10%: 1.12; 95% CI: 1.04-1.21; P = 0.003) but not MLA (adjusted HR per 1 mm2: 1.02; 95% CI: 0.99-1.04; P = 0.18) was associated with long-term all-cause death. These findings were also consistent for long-term cardiac mortality. CONCLUSIONS: In the present large-scale study with a 12-year follow-up, increasing LMCA plaque burden was associated with long-term all-cause and cardiac mortality in patients not undergoing LMCA revascularization, even when the lumen area was preserved.

Optical Coherence Tomography Fractional Flow Reserve and Cardiovascular Outcomes in Patients With Acute Coronary Syndrome.

BACKGROUND: Optical coherence tomography-derived fractional flow reserve (OCT-FFR) correlates strongly with wire-based FFR; however, its clinical significance remains uncertain. OBJECTIVES: This study sought to investigate the relationship between post-percutaneous coronary intervention (PCI) OCT-FFR and long-term clinical outcomes in acute coronary syndrome (ACS). METHODS: This retrospective, multicenter, observational cohort study included consecutive patients with ACS who underwent OCT-guided emergency PCI. We analyzed post-PCI OCT images and calculated OCT-FFR to identify independent factors associated with target vessel failure (TVF) after PCI. RESULTS: Among 364 enrolled patients, 54 experienced TVF during a median follow-up of 36 (IQR: 26-48) months. Vessel-level OCT-FFR was significantly lower in the TVF group than in the non-TVF group (0.87 vs 0.94; P < 0.001). In the multivariable Cox regression analysis, low vessel-level OCT-FFR (HR per 0.1 increase: 0.38; 95% CI: 0.29-0.49; P < 0.001) and thin-cap fibroatheroma in the nonculprit lesion were independently associated with TVF. The TVF rate of vessels with both low vessel-level OCT-FFR (<0.90) and thin-cap fibroatheroma in the nonculprit lesion was 8.1 times higher than that of all other vessels (69.3% vs 12.4%; HR: 8.13; 95% CI: 4.33-15.25; log-rank P < 0.001). Furthermore, adding vessel-level OCT-FFR to baseline characteristics and post-PCI OCT findings improved discriminatory and reclassification ability in identifying patients with subsequent TVF. CONCLUSIONS: Vessel-level OCT-FFR was an independent factor associated with TVF after PCI in patients with ACS. Adding the OCT-FFR measurement to post-PCI OCT findings may enable better discrimination of patients with subsequent TVF after PCI for ACS. (Relationship between Intracoronary Optical Coherence Tomography Derived Virtual Fractional Flow Reserve and cardiovascular outcome on Acute coronary syndrome; UMIN000043858).

Prevalence and Impact of Neoatherosclerosis on Clinical Outcomes After Percutaneous Treatment of Second-Generation Drug-Eluting Stent Restenosis.

BACKGROUND: Clinical and morphological factors associated with lipidic versus calcified neoatherosclerosis within second-generation drug-eluting stents and the impact of lipidic versus calcified neoatherosclerosis on long-term outcomes after repeat intervention have not been well studied. METHODS: A total of 512 patients undergoing optical coherence tomography before percutaneous coronary intervention for second-generation drug-eluting stents in-stent restenosis were included. Neoatherosclerosis was defined as lipidic or calcified neointimal hyperplasia in ≥3 consecutive frames or ruptured lipidic neointimal hyperplasia. The primary outcome was target lesion failure (cardiac death, target vessel myocardial infarction, definite stent thrombosis, or clinically driven target lesion revascularization). RESULTS: The overall prevalence of neoatherosclerosis was 28.5% (146/512): 56.8% lipidic, 30.8% calcified, and 12.3% both lipidic and calcific. The prevalence increased as a function of time from stent implantation: 20% at 1 to 3 years, 30% at 3 to 7 years, and 75% >7 years. Renal insufficiency, poor lipid profile, and time from stent implantation were associated with lipidic neoatherosclerosis, whereas severe renal insufficiency, female sex, and time from stent implantation were associated with calcified neoatherosclerosis. Multivariable Cox regression revealed that female sex and lipidic neoatherosclerosis were associated with more target lesion failure, whereas stent age and final minimum lumen diameter after reintervention were related to lower target lesion failure. Calcified neoatherosclerosis was not related to adverse events after reintervention for in-stent restenosis given a large enough minimum lumen diameter was achieved. CONCLUSIONS: Lipidic but not calcified neoatherosclerosis was associated with poor subsequent outcomes after repeat revascularization if optimal stent expansion was achieved in lesions with calcified neoatherosclerosis.

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.

Inter-observer differences in interpretation of coronary pressure-wire pullback data by non-expert interventional cardiologists.

The physiological pattern of coronary artery disease as determined by pressure-wire (PW)-pullback is important for decision-making of revascularization and risk stratification of patients. However, it remains unclear whether inter-observer differences in interpreting PW-pullback data are subject to the expertise of physicians. This study sought to investigate the subjectivity of this assessment among non-experts. Expert interventional cardiologists classified 545 PW-pullback traces into physiologically focal or physiologically diffuse disease pattern. Defining expert-consensus as the reference standard, we evaluated ten non-expert doctors' classification performance. Observers were stratified equally by two ways: (i) years of experience as interventional cardiologists (middle-level vs. junior-level) and (ii) volume of institutions where they belonged to (high-volume center vs. low-volume center). When judged against the expert-consensus, the agreement of non-expert observers in assessing physiological pattern of disease (focal or diffuse) ranged from 69.1 to 85.0% (p for heterogeneity < 0.0001). There was no evidence for a moderating effect of years of experience; the pooled accuracy of middle-level doctors was 78.8% (95% confidential interval [CI] 72.8-84.7%) vs. 79.1% for junior-level doctors (95% CI 75.9-82.2%, p = 0.95 for difference). On the other hand, we observed a significant moderating effect of center volume. Accuracy across non-experts in high-volume centers was 82.7% (95% CI 80.3-85.1%) vs. 75.1% for low-volume centers (95% CI 71.9-78.3%, p = 0.0002 for difference). Interpretation of PW-pullback by non-expert interventional cardiologists was considerably subjective.

Functional assessment of tandem coronary artery stenosis by intracoronary optical coherence tomography-derived virtual fractional flow reserve: a case series.

BACKGROUND: Optical coherence tomography (OCT)-derived fractional flow reserve (FFR)-which may be calculated using fluid dynamics-demonstrated an excellent correlation with the wire-based FFR. However, the applicability of the OCT-derived FFR in the assessment of tandem lesions is currently unclear. CASE SUMMARY: We present two cases of tandem lesions in the mid segment of the left anterior descending (LAD) artery which could have assessed accurately by OCT-derived FFR. The first patient underwent wire-based FFR at the far distal site of LAD, showed a value of 0.66. The OCT-derived FFR was calculated, yielding a value of 0.64. In the absence of stenosis at the proximal lesion, the OCT-derived FFR was calculated as 0.79, which was as same as the wire-based FFR obtained after stenting to the proximal lesion. Thus, additional stenting was performed at the distal lesion. The second patient underwent wire-based FFR at the far distal site of LAD, showed a value of 0.76 which was as same vale as OCT-derived FFR. Considering the absence of stenosis in the proximal lesion, the OCT-derived FFR was estimated as 0.88. After coronary stenting in the proximal lesion, the wire-based FFR yielded a value of 0.90. Therefore, additional intervention to the distal lesion was deferred. DISCUSSION: The described reports are the first two cases which performed physiological assessment using OCT in tandem lesions. The OCT-derived FFR might be able to estimate the wire-based FFR and the severity of each individual lesion in patients with tandem lesions.

Intravascular Ultrasound-Derived Virtual Fractional Flow Reserve for the Assessment of Myocardial Ischemia.

BACKGROUND: Fractional flow reserve (FFR) is widely used for the assessment of myocardial ischemia. Intravascular ultrasound (IVUS) is an intracoronary imaging method that provides information about lumen and vessel morphology. Previous studies on the expanded use of IVUS to identify functional ischemia have noted an association between anatomy and physiology, but IVUS-derived minimum lumen area (MLA) has a weak-moderate correlation with myocardial ischemia compared with FFR. We developed a method to calculate FFR using IVUS-derived anatomical information for the assessment of myocardial ischemia. The aims of this study were to investigate the relationship between wire-based FFR and IVUS-derived FFR (IVUS-FFR) and to compare the usefulness of IVUS-FFR and IVUS-derived MLA for functional assessment.Methods and Results:We retrospectively analyzed 50 lesions in 48 patients with coronary stenosis who underwent IVUS and FFR simultaneously. IVUS-FFR was calculated using our original algorithm and fluid dynamics. Mean percent diameter stenosis determined on quantitative coronary angiography and on FFR was 56.4±10.7 and 0.69±0.08, respectively. IVUS-FFR had a stronger linear correlation with FFR (R=0.78, P<0.001; root mean square error, 0.057 FFR units) than with IVUS-derived MLA (R=0.43, P=0.002). CONCLUSIONS: IVUS-FFR may be a more valuable method to identify myocardial ischemia, compared with IVUS-derived MLA.

Clinical significance of atrial high-rate episodes for thromboembolic events in Japanese population.

OBJECTIVE: The clinical significance of atrial high-rate episodes (AHREs) detected by cardiac devices among patients with implantable pacemakers has recently emerged. However, the relationship between AHREs and ischaemic stroke and systemic embolism (SE) is not well understood in the Japanese population. METHODS: This study included 343 patients with pacemakers capable of continuous atrial rhythm monitoring (167 males; mean age, 80±7 years). Atrial tachyarrhythmia detection was programmed to the nominal setting of each device, and AHRE was defined as any episode of sustained atrial tachyarrhythmia lasting for more than 6 min. Thromboembolic risk was defined based on the CHADS2 score. RESULTS: During the follow-up period (52±30 months), 165 (48%) patients had at least one episode of AHREs, and 19 (6%) patients experienced stroke/SE. Among patients who experienced stroke/SE, 14 had AHREs before the stroke/SE. AHREs were significantly associated with stroke/SE (HR 2.87; 95% CI 1.10 to 8.90; p=0.03). Subgroup analysis conducted to investigate the impact of the CHADS2 score severity on stroke/SE revealed that AHREs were not associated with stroke/SE in patients with low or intermediate thromboembolic risk (CHADS2 score 0-2; n=217). In contrast, among patients with high thromboembolic risk (CHADS2 score>2; n=126), there was a significant association between AHREs and the incidence of stroke/SE (HR 3.73; 95% CI 1.06 to 13.1; p=0.04). CONCLUSION: AHREs detected by pacemaker were associated with ischaemic stroke/SE in the Japanese population. However, this association was observed only in the high thromboembolic risk group.

Intracoronary Optical Coherence Tomography-Derived Virtual Fractional Flow Reserve for the Assessment of Coronary Artery Disease.

Fractional flow reserve (FFR) is widely used for the assessment of myocardial ischemia. Optical coherence tomography (OCT) provides accurate visualization of coronary artery morphology. The aim of this study was to investigate the relation between FFR and OCT-derived FFR. We retrospectively analyzed 31 lesions (25 left anterior descending arteries, 2 left circumflex arteries, and 4 right coronary arteries) in 31 patients with moderate-to-severe coronary stenosis, who underwent OCT and FFR measurements simultaneously. OCT-derived FFR was calculated by the original algorithm, which was calculated using the following equation based on fluid dynamics: ΔP = FV + SV2, where V is the flow velocity, F is the coefficient of pressure loss because of viscous friction (Poiseuille resistance), and S is the coefficient of local pressure loss because of abrupt enhancement (flow separation). Mean values of % diameter stenosis by quantitative coronary angiography and FFR were 55.2 ± 14.0% and 0.70 ± 0.14, respectively. OCT-derived FFR showed a stronger linear correlation with FFR measurements (r = 0.89, p <0.001; root mean square error = 0.062 FFR units) than quantitative coronary angiography % diameter stenosis (r = -0.65, p <0.001), OCT measurements of minimum lumen area (r = 0.68, p <0.001), and % area stenosis (r = -0.70, p <0.001). OCT-derived FFR has the potential to become an alternative method for the assessment of functional myocardial ischemia, and may elucidate the relation between coronary morphology and FFR.