Junya Shite - Academia.edu (original) (raw)
Papers by Junya Shite
JACC: Cardiovascular Interventions, 2015
The present study sought to determine whether optical coherence tomography (OCT) guidance results... more The present study sought to determine whether optical coherence tomography (OCT) guidance results in a degree of stent expansion comparable to that with intravascular ultrasound (IVUS) guidance. The most important predictor of adverse outcomes (thrombosis and restenosis) after stent implantation with IVUS guidance is the degree of stent expansion achieved. We compared the relative degree of stent expansion (defined as the minimal stent area divided by the mean of the proximal and distal reference lumen areas) after OCT-guided stenting in patients in the ILUMIEN (Observational Study of Optical Coherence Tomography [OCT] in Patients Undergoing Fractional Flow Reserve [FFR] and Percutaneous Coronary Intervention) (N = 354) and IVUS-guided stenting in patients in the ADAPT-DES (Assessment of Dual Antiplatelet Therapy With Drug-Eluting Stents) study (N = 586). Stent expansion was examined in all 940 patients in a covariate-adjusted analysis as well as in 286 propensity-matched pairs (total N = 572). In the matched-pair analysis, the degree of stent expansion was not significantly different between OCT and IVUS guidance (median [first, third quartiles] = 72.8% [63.3, 81.3] vs. 70.6% [62.3, 78.8], respectively, p = 0.29). Similarly, after adjustment for baseline differences in the entire population, the degree of stent expansion was also not different between the 2 imaging modalities (p = 0.84). Although a higher prevalence of post-PCI stent malapposition, tissue protrusion, and edge dissections was detected by OCT, the rates of major malapposition, tissue protrusion, and dissections were similar after OCT- and IVUS-guided stenting. In the present post-hoc analysis of 2 prospective studies, OCT and IVUS guidance resulted in a comparable degree of stent expansion. Randomized trials are warranted to compare the outcomes of OCT- and IVUS-guided coronary stent implantation.
Journal of Cardiology, 2015
This study aimed to assess chronic-phase suppression of neointimal proliferation and arterial hea... more This study aimed to assess chronic-phase suppression of neointimal proliferation and arterial healing following paclitaxel-coated (PTX) and bare metal stent (BMS) implantation in the superficial femoral artery using optical coherence tomography (OCT). Twenty-five patients with 68 stents underwent an 8-month OCT follow-up. Besides standard OCT variables, neointimal characterization and frequencies of peri-strut low-intensity area (PLIA), macrophage accumulation, and in-stent thrombi were evaluated. The mean neointimal thickness was significantly less with PTX stents (544.9±202.2μm vs. 865.0±230.6μm, p<0.0001). The covered and uncovered strut frequencies were significantly smaller and larger, respectively, in the PTX stent group vs. the BMS group (93.7% vs. 99.4%; p<0.0001, 4.0% vs. 0.4%; p<0.0001, respectively). Heterogeneous neointima was only observed in the PTX stent group (12.5% vs. 0%, p=0.017). The frequencies of PLIA and macrophage accumulation were significantly greater in the PTX stent group (87.2% vs. 67.6%, p=0.001 and 46% vs. 9.1%, p=0.003, respectively). After 8 months, reduced neointimal proliferation was observed with PTX stent implantation. On the other hand, delayed arterial healing was observed compared with BMS.
The Journal of invasive cardiology
We investigated the usefulness of optical coherence tomography (OCT) to evaluate vessel response ... more We investigated the usefulness of optical coherence tomography (OCT) to evaluate vessel response after stent implantation by comparing with that of intravascular ultrasound (IVUS). Eighteen cases undergoing percutaneous coronary intervention (PCI) who provided consent for both IVUS and OCT usage pre- and post-PCI procedure were enrolled. The lumen area at the distal site of the culprit lesion was smaller on OCT images than on IVUS images due to proximal vessel occlusion, whereas the lumen area at the proximal site of the lesion did not differ between OCT and IVUS images (distal site: 4.6 ± 2.0 vs. 5.0 ± 1.8 mm²; p = 0.0004; proximal site: 5.5 ± 2.3 vs. 5.6 ± 2.3 mm²; p = 0.8160). Stent malapposition was more frequently observed by OCT (30%) than by IVUS (5%, p = 0.0381). Stent edge dissection was not detected by IVUS, but was detected in 10% by OCT. Tissue prolapse was identified in all stents by OCT and in 5% by IVUS. Thrombus was observed in 15% by OCT and in 5% by IVUS. Proximal coronary occlusion during OCT imaging was possibly related to underestimation of vessel sizing at distal reference. Our data suggested that OCT might provide more detailed information on the presence of tissue prolapse, thrombus formation and edge dissection than IVUS. Further study is warranted to assess its clinical utility.
European heart journal, Jan 4, 2015
ILUMIEN I is the largest prospective, non-randomized, observational study of percutaneous coronar... more ILUMIEN I is the largest prospective, non-randomized, observational study of percutaneous coronary intervention (PCI) procedural practice in patients undergoing intra-procedural pre- and post-PCI fractional flow reserve (FFR) and optical coherence tomography (OCT). We report on the impact of OCT on physician decision-making and the association with post-PCI FFR values and early clinical events. Optical coherence tomography and documentary FFR were performed pre- and post-PCI in 418 patients (with 467 stenoses) with stable or unstable angina or NSTEMI. Based on pre-PCI OCT, the procedure was altered in 55% of patients (57% of all stenoses) by selecting different stent lengths (shorter in 25%, longer in 43%). After clinically satisfactory stent implantation using angiographic guidance, post-PCI FFR and OCT were repeated. Optical coherence tomography abnormalities deemed unsatisfactory by the implanting physician were identified: 14.5% malapposition, 7.6% under-expansion, 2.7% edge dis...
To evaluate the feasibility of the combined use of virtual histology (VH)-intravascular ultrasoun... more To evaluate the feasibility of the combined use of virtual histology (VH)-intravascular ultrasound (IVUS) and optical coherence tomography (OCT) for detecting in vivo thin-cap fibroatheroma (TCFA). In 56 patients with angina, 126 plaques identified by IVUS findings were analysed using both VH-IVUS and OCT. IVUS-derived TCFA was defined as an abundant necrotic core (>10% of the cross-sectional area) in contact with the lumen (NCCL) and %plaque-volume >40%. OCT-derived TCFA was defined as a fibrous cap thickness of <65 microm overlying a low-intensity area with an unclear border. Plaque meeting both TCFA criteria was defined as definite-TCFA. Sixty-one plaques were diagnosed as IVUS-derived TCFA and 36 plaques as OCT-derived TCFA. Twenty-eight plaques were diagnosed as definite-TCFA; the remaining 33 IVUS-derived TCFA had a non-thin-cap and eight OCT-derived TCFA had a non-NCCL (in discord with NCCL visualized by VH-IVUS, mainly due to misreading caused by dense calcium). Based on IVUS findings, definite-TCFA showed a larger plaque and vessel volume, %plaque-volume, higher vessel remodelling index, and greater angle occupied by the NCCL in the lumen circumference than non-thin-cap IVUS-derived TCFA. Conclusion Neither modality alone is sufficient for detecting TCFA. The combined use of OCT and VH-IVUS might be a feasible approach for evaluating TCFA.
Journal of cardiology, Jan 23, 2015
Human atrial natriuretic peptide (hANP) and spontaneous nitric oxide (NO) donor share cyclic guan... more Human atrial natriuretic peptide (hANP) and spontaneous nitric oxide (NO) donor share cyclic guanosine monophosphate (cGMP) as a second messenger, but their effect on myocardium may differ. We compared the effect of hANP and sodium nitroprusside (SNP) on left ventricular (LV) mechano-energetics in heart failure (HF). Ten patients with HF due to previous myocardial infarction (LV ejection fraction: 45±3%) were instrumented with conductance and coronary sinus thermodilution catheters. LV contractility (Ees: slope of end-systolic pressure-volume relation) and the ratio of LV stroke work (SW) to myocardial oxygen consumption (SW/MVO2=mechanical efficiency) were measured in response to intravenous infusion of ANP (0.05μg/kg/min) or SNP (0.3μg/kg/min) to lower blood pressure by at least 10mmHg, and changes in plasma cGMP. SNP had no effect on Ees, SW, or MVO2, thus SW/MVO2 remained unchanged (40.54±5.84% to 36.59±5.72%, p=0.25). ANP increased Ees, and decreased MVO2 with preserved SW, res...
Nihon rinsho. Japanese journal of clinical medicine, 2011
International Journal of Cardiology, 2015
The contribution of clopidogrel response due to cytochrome P450 (CYP) 2C19 loss-of-function polym... more The contribution of clopidogrel response due to cytochrome P450 (CYP) 2C19 loss-of-function polymorphism after drug-eluting stent (DES) implantation is unclear. A total of 196 patients who had undergone optical coherence tomography (OCT) at 8 months following first-generation DES (120 lesions) and current-generation everolimus-eluting stent (EES) implantation (127 lesions) were enrolled. Patients were divided into 3 groups by CYP2C19 polymorphism: extensive metabolizers (EMs), intermediate metabolizers (IMs), and poor metabolizers (PMs). OCT findings were compared among the 3 groups. Responsiveness to clopidogrel was assessed by VerifyNow platelet reactivity unit (PRU). The incidence of intra-stent thrombi was significantly higher after first-generation DES implantation compared with EES implantation (35% vs 13%, respectively; p=0.0001). In the first-generation DES group, the incidence of intra-stent thrombi significantly increased among EMs, IMs, and PMs (21% vs 36% vs 63%, respectively; p=0.007), while there was no significant difference among the 3 groups after EES implantation (10% vs 13% vs 20%, respectively; p=0.55). The PRU significantly increased among EMs, IMs, and PMs in each stent group. In multivariate analyses, although PMs had a 3-fold higher risk of thrombi formation compared with non-PMs after first-generation DES implantation, there were no significant differences in thrombi formation between the 2 groups after EES implantation. The optimal PRU cutoff values for the prediction of intra-stent thrombi with first-generation DES and EES were 234 and 256, respectively. CYP2C19 loss-of-function polymorphism is associated with a higher incidence of intra-stent thrombi after first-generation DES implantation, while the impact is attenuated following EES implantation.
Canadian Journal of Cardiology, 2015
The Nobori (Terumo Corporation, Tokyo, Japan) is a biolimus A9-eluting stent (BES) featured with ... more The Nobori (Terumo Corporation, Tokyo, Japan) is a biolimus A9-eluting stent (BES) featured with a biodegradable polymer coated on the abluminal side only. We previously reported that favourable vessel healing was achieved at 6-12 months after BES implantation. However, detailed long-term vessel reaction after BES deployment is unclear. Twenty-two BESs were serially evaluated using optical coherence tomography (OCT) at 6, 12, and 24 months after stenting. Average neointimal thickness, uncovered struts, and neointimal unevenness score (each cross-section as maximum neointimal thickness in 1 cross section divided by the average neointimal thickness of the same cross-section) were manually measured. In addition, we evaluated the percentage of struts with peri-strut low-intensity area (a region around stent struts that homogenously showed less intensity than the surrounding tissue, which suggests fibrin deposition or impaired neointima maturation), thrombi, and atherogenic neointimas (neointimas containing a diffuse border and poor-signal region with invisible struts due to marked signal attenuation). Serial OCT observation revealed a small gradual increase in neointimal thickness from 6 to 24 months (73 ± 24 μm; 81 ± 26 μm; and 108 ± 35 μm, respectively, P = 0.001) with a nonsignificant decrease in the lumen area (6.36 ± 1.98 mm(2); 6.18 ± 2.04 mm(2); and 5.87 ± 2.06 mm(2); P = 0.72). Frequency of uncovered struts (3.89 ± 3.91%; 1.55 ± 1.63%; and 0.23 ± 0.67%; P = 0.001), neointimal unevenness score (1.95 ± 0.18% to 1.86 ± 0.19% to 1.78 ± 0.17; P = 0.012), percentage of thrombi (5%, 0%, and 0%; P = 0.37) and peri-strut low-intensity area (6.8%, 5.1%, and 1.6%; P = 0.017) decreased from 6 to 12 and 24 months. Atherogenic neointima was not observed in the event-free OCT cohort. The Nobori stent achieved acceptable long-term vessel healing, mostly without adverse vessel reactions.
Europace, 2015
Left bundle branch block (LBBB) induces mechanical dyssynchrony, thereby compromising the coronar... more Left bundle branch block (LBBB) induces mechanical dyssynchrony, thereby compromising the coronary circulation in non-ischaemic cardiomyopathy. We sought to examine the effects of cardiac resynchronization therapy (CRT) on coronary flow dynamics and left ventricular (LV) function.
Cardiovascular Engineering and Technology, 2011
Image-based computational models for quantifying hemodynamic indices in stented coronary arteries... more Image-based computational models for quantifying hemodynamic indices in stented coronary arteries often employ biplane angiography and intravascular ultrasound for 3D reconstruction. Recent advances in guidewire simulation algorithms and the rise of optical coherence tomography (OCT) suggest more precise coronary artery reconstruction may be possible. We developed a patientspecific method that combines the superior resolution of OCT with techniques for imaging wire pathway reconstruction adopted from graph theory. The wire pathway with minimum bending energy was determined by applying a shortest path algorithm to a graph representation of the artery based on prior studies indicating a wire adopts the straightest configuration within a tortuous vessel. Segments from OCT images are then registered orthogonal to the wire pathway using rotational orientation consistent with geometry delineated by computed tomography (CT). To demonstrate applicability, OCT segments within the stented region were combined with proximal and distal CT segments and imported into computational fluid dynamics software to quantify indices of wall shear stress (WSS). The method was applied to imaging data of a left circumflex artery with thrombus acquired immediately post-stenting and after a 6-month follow-up period. Areas of stent-induced low WSS returned to physiological levels at follow-up, but correlated with measurable neointimal thickness in OCT images. Neointimal thickness was negligible in areas of elevated WSS due to thrombus. This novel methodology capable of reconstructing a stented coronary artery may ultimately enhance our knowledge of deleterious hemodynamic indices induced by stenting after further investigation in a larger patient population.
Journal of the American College of Cardiology, 2001
We administered antioxidant vitamins to rabbits with pacing-induced cardiomyopathy to assess whet... more We administered antioxidant vitamins to rabbits with pacing-induced cardiomyopathy to assess whether antioxidant therapy retards the progression of congestive heart failure (CHF). Although oxidative stress is increased in CHF, whether progression of heart failure could be prevented or reduced by antioxidants is not known. Rabbits with chronic cardiac pacing and sham operation were randomized to receive a combination of beta-carotene, ascorbic acid and alpha-tocopherol, alpha-tocopherol alone or placebo over eight weeks. Echocardiography was used to measure cardiac function weekly. Resting hemodynamics and in vivo myocardial beta-adrenergic responsiveness were studied at week 8. Animals were then sacrificed for measuring myocardial beta-receptor density, norepinephrine (NE) uptake-1 site density, sympathetic neuronal marker profiles, tissue-reduced glutathione/oxidized glutathione (GSH/GSSG) ratio and oxidative damage of mitochondrial DNA (mtDNA). Rapid cardiac pacing increased myocardial oxidative stress as evidenced by reduced myocardial GSH/GSSG ratio and increased oxidized mtDNA and produced cardiac dysfunction, beta-adrenergic subsensitivity, beta-receptor downregulation, diminished sympathetic neurotransmitter profiles and reduced NE uptake-1 carrier density. A combination of antioxidant vitamins reduced the myocardial oxidative stress, attenuated cardiac dysfunction and prevented myocardial beta-receptor downregulation and sympathetic nerve terminal dysfunction. Administration of alpha-tocopherol alone produced similar effects, but the effects were less marked than those produced by the three vitamins together. Vitamins produced no effects in sham-operated animals. Antioxidant vitamins reduced tissue oxidative stress in CHF and attenuated the associated cardiac dysfunction, beta-receptor downregulation and sympathetic nerve terminal abnormalities. The findings suggest that antioxidant therapy may be efficacious in human CHF.
Journal of the American College of Cardiology, 2007
This study evaluated the efficacy of catheter-based transcoronary myocardial hypothermia (CTMH) i... more This study evaluated the efficacy of catheter-based transcoronary myocardial hypothermia (CTMH) in pigs with acute myocardial ischemia.
Journal of the American College of Cardiology, 2011
The effectiveness of clopidogrel is influenced by cytochrome P450 (CYP) 2C19*2 polymorphism and c... more The effectiveness of clopidogrel is influenced by cytochrome P450 (CYP) 2C19*2 polymorphism and concomitant use of proton pump inhibitors (PPIs). Despite the past study suggested that PPIs decreased the inhibition of platelet function by clopidogrel, its contribution to lesion outcome is unclear.
Journal of the American College of Cardiology, 2012
Journal of Cardiology, 2008
A 54 years old man underwent directional coronary atherectomy in segment 7 with a partial deep-cu... more A 54 years old man underwent directional coronary atherectomy in segment 7 with a partial deep-cut injury. A sirolimus-eluting stent (SES) was implanted at the restenosed post-atherectomy lesion. Six months after SES implantation, intravascular ultrasound (IVUS) examination revealed slight vessel enlargement although there were no malapposed struts. Optical coherence tomography (OCT) revealed partial stent malapposition. Ticlopidine was discontinued 3 months after SES implantation, but aspirin was continued. Twenty-nine months after SES implantation, after discontinuing aspirin for 7 days for colon polypectomy, the patient suffered an acute myocardial infarction at the SES implantation site. IVUS revealed further positive vessel remodeling and slight stent malapposition and OCT revealed extension of the previous stent malapposition and ulcer-like appearance around the stent struts. This case demonstrates that even a small partial SES malapposition that can be detected only by OCT has the potential to enlarge over time and the late malapposition may result in late thrombosis when anti-platelet therapy is discontinued.
Journal of Cardiology, 2013
Although hemodialysis (HD) is a suggested risk factor for stent thrombosis, its contribution to l... more Although hemodialysis (HD) is a suggested risk factor for stent thrombosis, its contribution to local vessel healing after drug-eluting stent (DES) implantation is unclear. A total of 121 patients (152 lesions treated with DES) who underwent 8-month follow-up coronary angiography with optical coherence tomography (OCT) were enrolled, and the findings were compared between patients with and without HD. To match baseline differences, mid-term OCT findings of 42 propensity score-matched lesions (21 non-HD vs. 21 HD) were compared. Effects of HD on the efficacy of antiplatelet therapy were also evaluated by VerifyNow assay (Accumetrics, San Diego, CA, USA). Patients with HD had a significantly higher rate of thrombus formation than those without (64% vs. 33%, p = 0.007), although the baseline parameters and lesion characteristics differed between the groups. Multivariate logistic regression analysis revealed that HD was associated with an increased risk of thrombus formation (odds ratio 5.991, 95% confidence interval: 1.972-18.199, p = 0.002). Even after propensity-matching for patient background and balancing of angiographic and OCT variables, the risk of thrombus formation remained significantly higher in HD patients. The P2Y12-reaction unit was significantly increased after HD (Pre HD: 211 ± 75 vs. Post HD: 262 ± 59, p = 0.01), but patients without HD showed no increase during the same elapsed time (221 ± 88 vs. 212 ± 96, p = 0.19). HD is a potential risk factor for subclinical thrombus attachment after DES therapy. Systemic problems, such as residual platelet reactivity, associated with HD as well as local vessel features in HD patients might contribute to the increased incidence of thrombus attachment and subsequent onset of thrombotic event after DES implantation.
JACC: Cardiovascular Interventions, 2009
Objectives We conducted this study to assess the prevalence and determinants of subclinical throm... more Objectives We conducted this study to assess the prevalence and determinants of subclinical thrombus after sirolimus-eluting stent (SES) implantation.
JACC: Cardiovascular Imaging, 2013
and Westford, Massachusetts O B J E C T I V E S The aim of this study was to investigate the reli... more and Westford, Massachusetts O B J E C T I V E S The aim of this study was to investigate the reliability of frequency domain optical coherence tomography (FD-OCT) for coronary measurements compared with quantitative coronary angiography (QCA) and intravascular ultrasound (IVUS).
International Journal of Cardiology, 2012
Recent pathological studies have demonstrated that peri-strut low intensity area (PLIA) seen on o... more Recent pathological studies have demonstrated that peri-strut low intensity area (PLIA) seen on optical coherence tomography (OCT) imaging represents the presence of fibrinogen and/or extracellular matrix. We sought to assess the clinical prevalence of PLIA and its relation to neointimal proliferation after the implantation of sirolimus- (SES) and paclitaxel-eluting stents (PES) in humans. Seventy patients underwent 6-months follow-up OCT after SES (43 stents) or PES (37 stents) implantation. PLIA was defined as a region around stent struts with homogenous lower intensity than surrounding tissue on OCT images without signal attenuation. The incidence of stent struts with PLIA (+PLIA struts) was calculated as the number of +PLIA struts/number of all struts (%). PES showed a higher incidence of stents with PLIA than SES (86% vs. 58%; p=0.005) with a higher prevalence of +PLIA struts (27.8±21.9% vs. 10.9±11.0%; p=0.0008). SES with PLIA showed a significantly greater neointimal thickness (NIT) than SES without PLIA (p=0.02), while PES showed a similar tendency (p=0.19). In a detailed strut basis analysis, average NIT on +PLIA struts were significantly greater than that on -PLIA struts in both SES and PES. In addition, average NIT was positively correlated with the prevalence of +PLIA struts (SES: Rho=0.73; p<0.0001, PES: Rho=0.58, p=0.0005) in both stents. The prevalence of PLIA was significantly higher in PES than in SES. The presence and extent of PLIA might be associated with intimal thickening after 1st-generation DES implantation.
JACC: Cardiovascular Interventions, 2015
The present study sought to determine whether optical coherence tomography (OCT) guidance results... more The present study sought to determine whether optical coherence tomography (OCT) guidance results in a degree of stent expansion comparable to that with intravascular ultrasound (IVUS) guidance. The most important predictor of adverse outcomes (thrombosis and restenosis) after stent implantation with IVUS guidance is the degree of stent expansion achieved. We compared the relative degree of stent expansion (defined as the minimal stent area divided by the mean of the proximal and distal reference lumen areas) after OCT-guided stenting in patients in the ILUMIEN (Observational Study of Optical Coherence Tomography [OCT] in Patients Undergoing Fractional Flow Reserve [FFR] and Percutaneous Coronary Intervention) (N = 354) and IVUS-guided stenting in patients in the ADAPT-DES (Assessment of Dual Antiplatelet Therapy With Drug-Eluting Stents) study (N = 586). Stent expansion was examined in all 940 patients in a covariate-adjusted analysis as well as in 286 propensity-matched pairs (total N = 572). In the matched-pair analysis, the degree of stent expansion was not significantly different between OCT and IVUS guidance (median [first, third quartiles] = 72.8% [63.3, 81.3] vs. 70.6% [62.3, 78.8], respectively, p = 0.29). Similarly, after adjustment for baseline differences in the entire population, the degree of stent expansion was also not different between the 2 imaging modalities (p = 0.84). Although a higher prevalence of post-PCI stent malapposition, tissue protrusion, and edge dissections was detected by OCT, the rates of major malapposition, tissue protrusion, and dissections were similar after OCT- and IVUS-guided stenting. In the present post-hoc analysis of 2 prospective studies, OCT and IVUS guidance resulted in a comparable degree of stent expansion. Randomized trials are warranted to compare the outcomes of OCT- and IVUS-guided coronary stent implantation.
Journal of Cardiology, 2015
This study aimed to assess chronic-phase suppression of neointimal proliferation and arterial hea... more This study aimed to assess chronic-phase suppression of neointimal proliferation and arterial healing following paclitaxel-coated (PTX) and bare metal stent (BMS) implantation in the superficial femoral artery using optical coherence tomography (OCT). Twenty-five patients with 68 stents underwent an 8-month OCT follow-up. Besides standard OCT variables, neointimal characterization and frequencies of peri-strut low-intensity area (PLIA), macrophage accumulation, and in-stent thrombi were evaluated. The mean neointimal thickness was significantly less with PTX stents (544.9±202.2μm vs. 865.0±230.6μm, p<0.0001). The covered and uncovered strut frequencies were significantly smaller and larger, respectively, in the PTX stent group vs. the BMS group (93.7% vs. 99.4%; p<0.0001, 4.0% vs. 0.4%; p<0.0001, respectively). Heterogeneous neointima was only observed in the PTX stent group (12.5% vs. 0%, p=0.017). The frequencies of PLIA and macrophage accumulation were significantly greater in the PTX stent group (87.2% vs. 67.6%, p=0.001 and 46% vs. 9.1%, p=0.003, respectively). After 8 months, reduced neointimal proliferation was observed with PTX stent implantation. On the other hand, delayed arterial healing was observed compared with BMS.
The Journal of invasive cardiology
We investigated the usefulness of optical coherence tomography (OCT) to evaluate vessel response ... more We investigated the usefulness of optical coherence tomography (OCT) to evaluate vessel response after stent implantation by comparing with that of intravascular ultrasound (IVUS). Eighteen cases undergoing percutaneous coronary intervention (PCI) who provided consent for both IVUS and OCT usage pre- and post-PCI procedure were enrolled. The lumen area at the distal site of the culprit lesion was smaller on OCT images than on IVUS images due to proximal vessel occlusion, whereas the lumen area at the proximal site of the lesion did not differ between OCT and IVUS images (distal site: 4.6 ± 2.0 vs. 5.0 ± 1.8 mm²; p = 0.0004; proximal site: 5.5 ± 2.3 vs. 5.6 ± 2.3 mm²; p = 0.8160). Stent malapposition was more frequently observed by OCT (30%) than by IVUS (5%, p = 0.0381). Stent edge dissection was not detected by IVUS, but was detected in 10% by OCT. Tissue prolapse was identified in all stents by OCT and in 5% by IVUS. Thrombus was observed in 15% by OCT and in 5% by IVUS. Proximal coronary occlusion during OCT imaging was possibly related to underestimation of vessel sizing at distal reference. Our data suggested that OCT might provide more detailed information on the presence of tissue prolapse, thrombus formation and edge dissection than IVUS. Further study is warranted to assess its clinical utility.
European heart journal, Jan 4, 2015
ILUMIEN I is the largest prospective, non-randomized, observational study of percutaneous coronar... more ILUMIEN I is the largest prospective, non-randomized, observational study of percutaneous coronary intervention (PCI) procedural practice in patients undergoing intra-procedural pre- and post-PCI fractional flow reserve (FFR) and optical coherence tomography (OCT). We report on the impact of OCT on physician decision-making and the association with post-PCI FFR values and early clinical events. Optical coherence tomography and documentary FFR were performed pre- and post-PCI in 418 patients (with 467 stenoses) with stable or unstable angina or NSTEMI. Based on pre-PCI OCT, the procedure was altered in 55% of patients (57% of all stenoses) by selecting different stent lengths (shorter in 25%, longer in 43%). After clinically satisfactory stent implantation using angiographic guidance, post-PCI FFR and OCT were repeated. Optical coherence tomography abnormalities deemed unsatisfactory by the implanting physician were identified: 14.5% malapposition, 7.6% under-expansion, 2.7% edge dis...
To evaluate the feasibility of the combined use of virtual histology (VH)-intravascular ultrasoun... more To evaluate the feasibility of the combined use of virtual histology (VH)-intravascular ultrasound (IVUS) and optical coherence tomography (OCT) for detecting in vivo thin-cap fibroatheroma (TCFA). In 56 patients with angina, 126 plaques identified by IVUS findings were analysed using both VH-IVUS and OCT. IVUS-derived TCFA was defined as an abundant necrotic core (>10% of the cross-sectional area) in contact with the lumen (NCCL) and %plaque-volume >40%. OCT-derived TCFA was defined as a fibrous cap thickness of <65 microm overlying a low-intensity area with an unclear border. Plaque meeting both TCFA criteria was defined as definite-TCFA. Sixty-one plaques were diagnosed as IVUS-derived TCFA and 36 plaques as OCT-derived TCFA. Twenty-eight plaques were diagnosed as definite-TCFA; the remaining 33 IVUS-derived TCFA had a non-thin-cap and eight OCT-derived TCFA had a non-NCCL (in discord with NCCL visualized by VH-IVUS, mainly due to misreading caused by dense calcium). Based on IVUS findings, definite-TCFA showed a larger plaque and vessel volume, %plaque-volume, higher vessel remodelling index, and greater angle occupied by the NCCL in the lumen circumference than non-thin-cap IVUS-derived TCFA. Conclusion Neither modality alone is sufficient for detecting TCFA. The combined use of OCT and VH-IVUS might be a feasible approach for evaluating TCFA.
Journal of cardiology, Jan 23, 2015
Human atrial natriuretic peptide (hANP) and spontaneous nitric oxide (NO) donor share cyclic guan... more Human atrial natriuretic peptide (hANP) and spontaneous nitric oxide (NO) donor share cyclic guanosine monophosphate (cGMP) as a second messenger, but their effect on myocardium may differ. We compared the effect of hANP and sodium nitroprusside (SNP) on left ventricular (LV) mechano-energetics in heart failure (HF). Ten patients with HF due to previous myocardial infarction (LV ejection fraction: 45±3%) were instrumented with conductance and coronary sinus thermodilution catheters. LV contractility (Ees: slope of end-systolic pressure-volume relation) and the ratio of LV stroke work (SW) to myocardial oxygen consumption (SW/MVO2=mechanical efficiency) were measured in response to intravenous infusion of ANP (0.05μg/kg/min) or SNP (0.3μg/kg/min) to lower blood pressure by at least 10mmHg, and changes in plasma cGMP. SNP had no effect on Ees, SW, or MVO2, thus SW/MVO2 remained unchanged (40.54±5.84% to 36.59±5.72%, p=0.25). ANP increased Ees, and decreased MVO2 with preserved SW, res...
Nihon rinsho. Japanese journal of clinical medicine, 2011
International Journal of Cardiology, 2015
The contribution of clopidogrel response due to cytochrome P450 (CYP) 2C19 loss-of-function polym... more The contribution of clopidogrel response due to cytochrome P450 (CYP) 2C19 loss-of-function polymorphism after drug-eluting stent (DES) implantation is unclear. A total of 196 patients who had undergone optical coherence tomography (OCT) at 8 months following first-generation DES (120 lesions) and current-generation everolimus-eluting stent (EES) implantation (127 lesions) were enrolled. Patients were divided into 3 groups by CYP2C19 polymorphism: extensive metabolizers (EMs), intermediate metabolizers (IMs), and poor metabolizers (PMs). OCT findings were compared among the 3 groups. Responsiveness to clopidogrel was assessed by VerifyNow platelet reactivity unit (PRU). The incidence of intra-stent thrombi was significantly higher after first-generation DES implantation compared with EES implantation (35% vs 13%, respectively; p=0.0001). In the first-generation DES group, the incidence of intra-stent thrombi significantly increased among EMs, IMs, and PMs (21% vs 36% vs 63%, respectively; p=0.007), while there was no significant difference among the 3 groups after EES implantation (10% vs 13% vs 20%, respectively; p=0.55). The PRU significantly increased among EMs, IMs, and PMs in each stent group. In multivariate analyses, although PMs had a 3-fold higher risk of thrombi formation compared with non-PMs after first-generation DES implantation, there were no significant differences in thrombi formation between the 2 groups after EES implantation. The optimal PRU cutoff values for the prediction of intra-stent thrombi with first-generation DES and EES were 234 and 256, respectively. CYP2C19 loss-of-function polymorphism is associated with a higher incidence of intra-stent thrombi after first-generation DES implantation, while the impact is attenuated following EES implantation.
Canadian Journal of Cardiology, 2015
The Nobori (Terumo Corporation, Tokyo, Japan) is a biolimus A9-eluting stent (BES) featured with ... more The Nobori (Terumo Corporation, Tokyo, Japan) is a biolimus A9-eluting stent (BES) featured with a biodegradable polymer coated on the abluminal side only. We previously reported that favourable vessel healing was achieved at 6-12 months after BES implantation. However, detailed long-term vessel reaction after BES deployment is unclear. Twenty-two BESs were serially evaluated using optical coherence tomography (OCT) at 6, 12, and 24 months after stenting. Average neointimal thickness, uncovered struts, and neointimal unevenness score (each cross-section as maximum neointimal thickness in 1 cross section divided by the average neointimal thickness of the same cross-section) were manually measured. In addition, we evaluated the percentage of struts with peri-strut low-intensity area (a region around stent struts that homogenously showed less intensity than the surrounding tissue, which suggests fibrin deposition or impaired neointima maturation), thrombi, and atherogenic neointimas (neointimas containing a diffuse border and poor-signal region with invisible struts due to marked signal attenuation). Serial OCT observation revealed a small gradual increase in neointimal thickness from 6 to 24 months (73 ± 24 μm; 81 ± 26 μm; and 108 ± 35 μm, respectively, P = 0.001) with a nonsignificant decrease in the lumen area (6.36 ± 1.98 mm(2); 6.18 ± 2.04 mm(2); and 5.87 ± 2.06 mm(2); P = 0.72). Frequency of uncovered struts (3.89 ± 3.91%; 1.55 ± 1.63%; and 0.23 ± 0.67%; P = 0.001), neointimal unevenness score (1.95 ± 0.18% to 1.86 ± 0.19% to 1.78 ± 0.17; P = 0.012), percentage of thrombi (5%, 0%, and 0%; P = 0.37) and peri-strut low-intensity area (6.8%, 5.1%, and 1.6%; P = 0.017) decreased from 6 to 12 and 24 months. Atherogenic neointima was not observed in the event-free OCT cohort. The Nobori stent achieved acceptable long-term vessel healing, mostly without adverse vessel reactions.
Europace, 2015
Left bundle branch block (LBBB) induces mechanical dyssynchrony, thereby compromising the coronar... more Left bundle branch block (LBBB) induces mechanical dyssynchrony, thereby compromising the coronary circulation in non-ischaemic cardiomyopathy. We sought to examine the effects of cardiac resynchronization therapy (CRT) on coronary flow dynamics and left ventricular (LV) function.
Cardiovascular Engineering and Technology, 2011
Image-based computational models for quantifying hemodynamic indices in stented coronary arteries... more Image-based computational models for quantifying hemodynamic indices in stented coronary arteries often employ biplane angiography and intravascular ultrasound for 3D reconstruction. Recent advances in guidewire simulation algorithms and the rise of optical coherence tomography (OCT) suggest more precise coronary artery reconstruction may be possible. We developed a patientspecific method that combines the superior resolution of OCT with techniques for imaging wire pathway reconstruction adopted from graph theory. The wire pathway with minimum bending energy was determined by applying a shortest path algorithm to a graph representation of the artery based on prior studies indicating a wire adopts the straightest configuration within a tortuous vessel. Segments from OCT images are then registered orthogonal to the wire pathway using rotational orientation consistent with geometry delineated by computed tomography (CT). To demonstrate applicability, OCT segments within the stented region were combined with proximal and distal CT segments and imported into computational fluid dynamics software to quantify indices of wall shear stress (WSS). The method was applied to imaging data of a left circumflex artery with thrombus acquired immediately post-stenting and after a 6-month follow-up period. Areas of stent-induced low WSS returned to physiological levels at follow-up, but correlated with measurable neointimal thickness in OCT images. Neointimal thickness was negligible in areas of elevated WSS due to thrombus. This novel methodology capable of reconstructing a stented coronary artery may ultimately enhance our knowledge of deleterious hemodynamic indices induced by stenting after further investigation in a larger patient population.
Journal of the American College of Cardiology, 2001
We administered antioxidant vitamins to rabbits with pacing-induced cardiomyopathy to assess whet... more We administered antioxidant vitamins to rabbits with pacing-induced cardiomyopathy to assess whether antioxidant therapy retards the progression of congestive heart failure (CHF). Although oxidative stress is increased in CHF, whether progression of heart failure could be prevented or reduced by antioxidants is not known. Rabbits with chronic cardiac pacing and sham operation were randomized to receive a combination of beta-carotene, ascorbic acid and alpha-tocopherol, alpha-tocopherol alone or placebo over eight weeks. Echocardiography was used to measure cardiac function weekly. Resting hemodynamics and in vivo myocardial beta-adrenergic responsiveness were studied at week 8. Animals were then sacrificed for measuring myocardial beta-receptor density, norepinephrine (NE) uptake-1 site density, sympathetic neuronal marker profiles, tissue-reduced glutathione/oxidized glutathione (GSH/GSSG) ratio and oxidative damage of mitochondrial DNA (mtDNA). Rapid cardiac pacing increased myocardial oxidative stress as evidenced by reduced myocardial GSH/GSSG ratio and increased oxidized mtDNA and produced cardiac dysfunction, beta-adrenergic subsensitivity, beta-receptor downregulation, diminished sympathetic neurotransmitter profiles and reduced NE uptake-1 carrier density. A combination of antioxidant vitamins reduced the myocardial oxidative stress, attenuated cardiac dysfunction and prevented myocardial beta-receptor downregulation and sympathetic nerve terminal dysfunction. Administration of alpha-tocopherol alone produced similar effects, but the effects were less marked than those produced by the three vitamins together. Vitamins produced no effects in sham-operated animals. Antioxidant vitamins reduced tissue oxidative stress in CHF and attenuated the associated cardiac dysfunction, beta-receptor downregulation and sympathetic nerve terminal abnormalities. The findings suggest that antioxidant therapy may be efficacious in human CHF.
Journal of the American College of Cardiology, 2007
This study evaluated the efficacy of catheter-based transcoronary myocardial hypothermia (CTMH) i... more This study evaluated the efficacy of catheter-based transcoronary myocardial hypothermia (CTMH) in pigs with acute myocardial ischemia.
Journal of the American College of Cardiology, 2011
The effectiveness of clopidogrel is influenced by cytochrome P450 (CYP) 2C19*2 polymorphism and c... more The effectiveness of clopidogrel is influenced by cytochrome P450 (CYP) 2C19*2 polymorphism and concomitant use of proton pump inhibitors (PPIs). Despite the past study suggested that PPIs decreased the inhibition of platelet function by clopidogrel, its contribution to lesion outcome is unclear.
Journal of the American College of Cardiology, 2012
Journal of Cardiology, 2008
A 54 years old man underwent directional coronary atherectomy in segment 7 with a partial deep-cu... more A 54 years old man underwent directional coronary atherectomy in segment 7 with a partial deep-cut injury. A sirolimus-eluting stent (SES) was implanted at the restenosed post-atherectomy lesion. Six months after SES implantation, intravascular ultrasound (IVUS) examination revealed slight vessel enlargement although there were no malapposed struts. Optical coherence tomography (OCT) revealed partial stent malapposition. Ticlopidine was discontinued 3 months after SES implantation, but aspirin was continued. Twenty-nine months after SES implantation, after discontinuing aspirin for 7 days for colon polypectomy, the patient suffered an acute myocardial infarction at the SES implantation site. IVUS revealed further positive vessel remodeling and slight stent malapposition and OCT revealed extension of the previous stent malapposition and ulcer-like appearance around the stent struts. This case demonstrates that even a small partial SES malapposition that can be detected only by OCT has the potential to enlarge over time and the late malapposition may result in late thrombosis when anti-platelet therapy is discontinued.
Journal of Cardiology, 2013
Although hemodialysis (HD) is a suggested risk factor for stent thrombosis, its contribution to l... more Although hemodialysis (HD) is a suggested risk factor for stent thrombosis, its contribution to local vessel healing after drug-eluting stent (DES) implantation is unclear. A total of 121 patients (152 lesions treated with DES) who underwent 8-month follow-up coronary angiography with optical coherence tomography (OCT) were enrolled, and the findings were compared between patients with and without HD. To match baseline differences, mid-term OCT findings of 42 propensity score-matched lesions (21 non-HD vs. 21 HD) were compared. Effects of HD on the efficacy of antiplatelet therapy were also evaluated by VerifyNow assay (Accumetrics, San Diego, CA, USA). Patients with HD had a significantly higher rate of thrombus formation than those without (64% vs. 33%, p = 0.007), although the baseline parameters and lesion characteristics differed between the groups. Multivariate logistic regression analysis revealed that HD was associated with an increased risk of thrombus formation (odds ratio 5.991, 95% confidence interval: 1.972-18.199, p = 0.002). Even after propensity-matching for patient background and balancing of angiographic and OCT variables, the risk of thrombus formation remained significantly higher in HD patients. The P2Y12-reaction unit was significantly increased after HD (Pre HD: 211 ± 75 vs. Post HD: 262 ± 59, p = 0.01), but patients without HD showed no increase during the same elapsed time (221 ± 88 vs. 212 ± 96, p = 0.19). HD is a potential risk factor for subclinical thrombus attachment after DES therapy. Systemic problems, such as residual platelet reactivity, associated with HD as well as local vessel features in HD patients might contribute to the increased incidence of thrombus attachment and subsequent onset of thrombotic event after DES implantation.
JACC: Cardiovascular Interventions, 2009
Objectives We conducted this study to assess the prevalence and determinants of subclinical throm... more Objectives We conducted this study to assess the prevalence and determinants of subclinical thrombus after sirolimus-eluting stent (SES) implantation.
JACC: Cardiovascular Imaging, 2013
and Westford, Massachusetts O B J E C T I V E S The aim of this study was to investigate the reli... more and Westford, Massachusetts O B J E C T I V E S The aim of this study was to investigate the reliability of frequency domain optical coherence tomography (FD-OCT) for coronary measurements compared with quantitative coronary angiography (QCA) and intravascular ultrasound (IVUS).
International Journal of Cardiology, 2012
Recent pathological studies have demonstrated that peri-strut low intensity area (PLIA) seen on o... more Recent pathological studies have demonstrated that peri-strut low intensity area (PLIA) seen on optical coherence tomography (OCT) imaging represents the presence of fibrinogen and/or extracellular matrix. We sought to assess the clinical prevalence of PLIA and its relation to neointimal proliferation after the implantation of sirolimus- (SES) and paclitaxel-eluting stents (PES) in humans. Seventy patients underwent 6-months follow-up OCT after SES (43 stents) or PES (37 stents) implantation. PLIA was defined as a region around stent struts with homogenous lower intensity than surrounding tissue on OCT images without signal attenuation. The incidence of stent struts with PLIA (+PLIA struts) was calculated as the number of +PLIA struts/number of all struts (%). PES showed a higher incidence of stents with PLIA than SES (86% vs. 58%; p=0.005) with a higher prevalence of +PLIA struts (27.8±21.9% vs. 10.9±11.0%; p=0.0008). SES with PLIA showed a significantly greater neointimal thickness (NIT) than SES without PLIA (p=0.02), while PES showed a similar tendency (p=0.19). In a detailed strut basis analysis, average NIT on +PLIA struts were significantly greater than that on -PLIA struts in both SES and PES. In addition, average NIT was positively correlated with the prevalence of +PLIA struts (SES: Rho=0.73; p<0.0001, PES: Rho=0.58, p=0.0005) in both stents. The prevalence of PLIA was significantly higher in PES than in SES. The presence and extent of PLIA might be associated with intimal thickening after 1st-generation DES implantation.