Comparison of diagnostic performance in assessing the rewiring position into a jailed side branch between online 3D reconstruction systems version 1.1 and 1.2 derived from optical frequency domain imaging.

The three-dimensional reconstruction of optical coherence tomography and optical frequency domain imaging (3D-OCT/OFDI) helps optimize bifurcation percutaneous coronary interventions (PCIs) with side branch (SB) dilatation by identifying the optimal rewiring position. 3D-OCT/OFDI's diagnostic performance for assessing the rewiring position into a jailed SB is unknown. We retrospectively evaluated the diagnostic performances of a conventional (ver. 1.1) and a new (ver. 1.2) online 3D-OFDI reconstruction system based on an offline 3D reconstruction system's performance. We analyzed 45 patients' 52 OFDI pullbacks with main vessel stenting followed by rewiring into a jailed SB for coronary bifurcation lesions. We counted the undetected stent struts in the polygon of confluence as the stent detection performance. We assessed the diagnostic agreement regarding the rewiring position into a jailed SB by the three 3D reconstruction systems. The percentage of undetected struts and the diagnostic agreement of ver.1.2 were significantly better than those of ver.1.1 [5.1 ± 5.1% vs. 30.2 ± 14.2%; p < 0.0001, and 94.2% (49/52) vs. 76.9% (40/52); p = 0.0120]. The new online 3D-OFDI reconstruction system provides better diagnostic performance than the conventional online system for assessing the rewiring position into a jailed SB.

Serial changes in the side-branch ostial area after main-vessel stenting with kissing balloon inflation for coronary bifurcation lesions, assessed by 3D optical coherence tomography.

Aims: We evaluated the influence of the jailing configuration and guidewire rewiring position in front of the side-branch (SB) ostium before kissing balloon inflation (KBI) against side-branch ostial area (SBOA) at follow-up using 3D optical coherence tomography (3D-OCT). Methods and results: We retrospectively analysed the cases of the 37 consecutive patients who underwent main-vessel (MV) stenting with KBI for coronary bifurcation lesion under OCT guidance and the follow-up OCT 6-12 months. We divided the patients into two groups, considering both the jailing configuration and the rewiring position by 3D-OCT. We defined the cases that achieved both the distal rewiring and link-free carina configuration as the FCD group, and the other cases were defined as the Non-FCD group. We compared the differences in the SBOA derived by the cut-plane analysis and the number of compartments between the two groups. The median and interquartile range of serial change and percent serial change in SBOA in the FCD group were significantly larger than those in the Non-FCD group [0.43 mm2 (-0.29 to 0.91) vs. -0.65 mm2 (-1.33 to 0.34); P = 0.0136 and 9.47% (-8.37 to 27.33) vs. -13.77% (-31.64 to 10.88); P = 0.0182]. Conclusion: This serial OCT study demonstrated that the achievement of both the distal rewiring and link-free carina configuration may be important for the preservation of the SBOA after MV stenting with KBI for coronary bifurcation lesions.

Serial changes in the three-dimensional aspect of the side-branch ostium jailed by a drug-eluting stent assessed by optical coherence tomography.

The present study investigated serial changes in the three-dimensional (3D) aspect of the jailed side-branch (SB) ostium. We evaluated 32 patients who underwent examination with optical coherence tomography (OCT) both at baseline and at follow-up. After reconstruction of the 3D images, we classified the configuration of overhanging struts at the SB orifice into three groups according to the 3D aspect of the jailing configuration. The number of compartments divided by the stent strut was counted. The side-branch flow area (SBFA), i.e., the area of the SB ostium except for jailing struts, was measured by cut-plane analysis. Forty-eight SBs of 25 patients were analyzed. Thirteen SBs were classified as the No-jail type (N-type), 19 as the Simple-jail type (S-type; no longitudinal link at the carina), and 16 as the Complex-jail type (C-type; had a link at the carina). In the N-type, the SBFA was significantly increased at follow-up (P = 0.018). In the C-type, the SBFA was significantly decreased at follow-up (P = 0.002). Percent reduction of SBFA in the C-type group was significantly greater than that in the N-type or S-type groups (S-type vs. C-type P = 0.002, N-type vs. C-type P < 0.001). 3D-OCT images showed that some of the compartments were filled with tissue. The number of compartments was significantly decreased at follow-up (P < 0.001). In the C-type group, the SBFA was significantly decreased and small compartments were filled with tissue. These findings suggest that stent jail complexity is associated with the progression of SB ostial stenosis.

Inferior J waves in patients with vasospastic angina might be a risk factor for ventricular fibrillation.

BACKGROUND: There is little information about the relationship between J waves and the occurrence of ventricular fibrillation (VF) in patients with vasospastic angina (VSA). The present study aimed to assess the incidence of J waves and the occurrence of VF in patients with VSA. METHODS: The subjects consisted of 62 patients with VSA diagnosed by acetylcholine provocation tests in our institution from 2002 to 2014. We investigated the VF events, prevalence of J waves, and relationship between the VF events and J waves. RESULTS: J waves were observed in 16 patients (26%) and VF events were documented in 11 (18%). The incidence of VF in the patients with J waves was significantly higher than that in those without J waves (38% vs 11%, p=0.026). J waves were observed in the inferior leads in 14 patients, lateral leads in 5, and anterior leads in 3. A univariate analysis indicated that the incidence of VF in the inferior leads of J wave positive patients (46%=6/14) was significantly (p=0.01) higher than that in the inferior leads of J wave negative patients (10%=5/48). The J waves in the anterior and/or lateral leads were not related to the incidence of VF. Notched type and slurred type J waves were not associated with VF. A multivariate analysis revealed that J waves in VSA patients were associated with VF [odds ratio (OR) 6.41, 95% confidence interval (CI) 1.37-29.93, p=0.02] and organic stenosis (OR 6.98, 95% CI 1.39-35.08, p=0.02). Further, J waves in the inferior leads were strongly correlated with VF (OR 11.85, 95% CI 2.05-68.42, p=0.006). CONCLUSIONS: The results suggest that the existence of J waves, especially in the inferior leads, might be a risk factor for VF in VSA patients.

Differences of side branch jailing between left main-left anterior descending artery stenting and left main-left circumflex artery stenting with Nobori biolimus-eluting stent.

The aim of this study is to indicate differences of side branch jailing between the left main (LM)-left anterior descending artery (LAD) stenting and the LM-left circumflex artery (LCx) stenting. Thirty-one patients who underwent single-stenting using a two-link ten-crowns biolimus-eluting stent (Japanese design of BES, J-BES) and subsequent kissing balloon dilation (KBD) on an LM bifurcation with optical coherence tomography (OCT) were divided into two groups according to the stented vessel. Bifurcation angles were measured by three-dimensional (3D) quantitative coronary analysis. The jailing pattern on a side branch ostium was evaluated by stent-enhanced 3D-OCT. Incomplete stent apposition (ISA) after KBD was compared between the stented vessels. The to-be-stented angle of the LM-LCx stenting (n = 11) was significantly steeper than that of the LM-LAD stenting (n = 20) (132.6° ± 16.9° vs. 150.7° ± 10.6°, p < 0.01). The incidence of the free carina type, which has no stent links bridging from a carina, in the LM-LCx stenting was significantly higher than that in the LM-LAD stenting (90.9 vs. 45.0 %, p = 0.02). The percentage of ISA at the bifurcation segment in the LM-LCx stenting was significantly smaller than that in the LM-LAD stenting (4.4 ± 8.2 vs. 12.7 ± 9.2 %, p = 0.0003). This study showed, by higher incidence of the favorable configuration, that the LM-LCx stenting achieved a smaller percentage of ISA than the LM-LAD stenting. These insights may help guide LM bifurcation stenting with J-BES.

Comparison of neointimal coverage and extra-stent lumen between sirolimus and everolimus-eluting stent using optical coherence tomography.

The external lumen of a stent [defined as extra-stent lumen (ESL)] assessed by optical coherence tomography (OCT) may be related to the risk of thrombus formation after sirolimus-eluting stent (SES) implantation. An everolimus-eluting stent (EES) might provide relatively minimal inflammatory reaction and appropriate neointimal coverage. The purpose of this study was to compare the neointimal thickness and ESL between SES and EES. Patients who underwent OCT examination more than 7 months after either SES or EES implantation were enrolled. Stent area (SA), lumen area (LA), neointimal area (NIA) and neointimal thickness (NIT) of each strut were measured at 1-mm intervals between stented segments. The area, angle (summation per cross-section) and depth (maximum distance from adjacent vessel surface to the outline of stent) of ESL were analyzed. A total of 49 lesions were included (SES n = 20, EES n = 29). Mean follow-up period was 11 months. A total of 998 cross-sections and 9874 struts were analyzed. There were no differences in stent area, lumen area and neointimal area (SA: 6.01 ± 1.60 vs. 6.02 ± 1.40 mm(2), p = 0.572, LA: 5.37 ± 1.52 vs. 5.29 ± 1.34 mm(2), p = 0.692, NIA: 0.64 ± 0.49 vs. 0.72 ± 0.37 mm(2), p = 0.493). Mean NIT of SES and EES were 0.11 ± 0.05 and 0.10 ± 0.05 mm, respectively (p = 0.367). Conversely, area, angle and depth of ESL in SES group were significantly greater than those in EES group (0.20 ± 0.39 vs. 0.03 ± 0.09 mm(2), p < 0.001, 56.2 ± 59.1° vs. 20.1 ± 41.9°, p < 0.001, 0.10 ± 0.09 vs. 0.03 ± 0.03 mm, p < 0.001). OCT showed that the efficacy of neointimal growth suppression is similar between SES and EES, whereas the adverse vascular response after EES implantation is smaller than that after SES implantation.

A Rare Case of Complete Stent Fracture, Coronary Arterial Transection, and Pseudoaneurysm Formation Induced by Repeated Stenting.

This report describes a rare asymptomatic case of complete stent fracture, coronary arterial transection, and pseudoaneurysm formation in response to repeated stenting. The proximal and distal ends of transected coronary artery were closed, and distal bypass was performed. Coronary arterial transection can occur in patients with repeated stenting as a long-term adverse event.

Urinary 8-hydroxy-2'-deoxyguanosine as a novel biomarker of inflammatory activity in patients with cardiac sarcoidosis.

BACKGROUND: Inflammation and oxidative stress play a crucial role in the pathogenesis of cardiac sarcoidosis (SAR). We investigated whether urinary (U) 8-hydroxy-2'-deoxyguanosine (8-OHdG)--an oxidative DNA damage marker--was related to SAR inflammatory activity. METHODS: U-8-OHdG levels were measured in 31 SAR patients, classified as active (n=17) or non-active (n=14) based on (18)F-fluorodeoxyglucose positron emission tomography-computed tomography ((18)F-FDG-PET/CT), 28 dilated cardiomyopathy (DCM) patients, and 30 controls. In active SAR patients, U-8-OHdG levels were reexamined and compared with (18)F-FDG-PET/CT results at 6 months after corticosteroid treatment to assess therapeutic response. RESULTS: Immunohistochemical examination of left ventricle (LV) autopsy samples from SAR patients revealed positive 8-OHdG staining in cardiomyocyte nuclei from LV sections showing (18)F-FDG accumulation on PET/CT, while serum 8-OHdG levels were significantly higher in the coronary sinus than in the aortic root only in active SAR patients. U-8-OHdG levels in SAR patients were higher than those in controls, and significantly higher in active SAR patients than in non-active SAR and DCM patients. U-8-OHdG was a powerful predictor of active SAR in receiver operating characteristic curve analysis (AUC, 0.98; 95% CI, 0.94-1.02; optimal cutoff value, 13.1 ng/mg creatinine), with a sensitivity of 88.2% and a specificity of 92.9%. U-8-OHdG levels in responders significantly decreased at 6 months after corticosteroid treatment initiation, in proportion with the decrease in the focal cardiac uptake of (18)F-FDG. CONCLUSIONS: U-8-OHdG is a potentially clinically useful biomarker for evaluating inflammatory activity and monitoring the effectiveness of corticosteroid therapy in SAR patients.

New quantitative method to diagnose coronary in-stent restenosis by 64-multislice computed tomography.

BACKGROUND: The aim of this study is to evaluate the accuracy of a newly developed quantitative method using 64-multislice computed tomography angiography (CTA) to detect coronary in-stent restenosis (ISR). METHODS AND RESULTS: CTA was performed in 45 patients who underwent stent implantation (79 lesions) and the accuracy to diagnose ISR was evaluated by comparing with invasive coronary angiography (ICA). CTA was evaluated both visually and quantitatively using a new stent restenosis index (SRI) utilizing CT densities at proximal and distal artery lumen from the stented region and the correction value depending on the stent diameter. ICA showed 11 ISR (14%). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for visual evaluation were 78%, 75%, 35%, 95%, and 76%, respectively. On the other hand, the quantitative evaluation using SRI represents 82%, 93%, 64%, 97%, and 91%, respectively. CONCLUSIONS: Evaluation of ISR using SRI is superior to the visual estimation of CTA.

3D optical coherence tomography: new insights into the process of optimal rewiring of side branches during bifurcational stenting.

AIMS: We describe three-dimensional optical coherence tomography (3D-OCT) guided bifurcation stenting and the clinical utility of 3D-OCT. METHODS AND RESULTS: Twenty-two consecutive patients who underwent OCT examination to confirm the recrossing position after stent implantation in a bifurcation lesion were enrolled. Frequency domain OCT images were obtained to check the recrossing position and 3D reconstructions were performed off-line. The recrossing position was clearly visualised in 18/22 (81.8%) cases. In 13 cases, serial 3D-OCT could be assessed both before and after final kissing balloon post-dilation (FKBD). We divided these cases into two groups according to the presence of the link between hoops at the carina: free carina type (n=7) and connecting to carina type (n=6). All free carina types complied with the distal rewiring. The percentage of incomplete stent apposition (%ISA) of free carina type at the bifurcation segment after FKBD was significantly smaller than that of the connecting to carina type (0.7±0.9% vs. 12.2±6.5%, p=0.0074). CONCLUSIONS: 3D-OCT confirmation of the recrossing into the jailed side branch is feasible during PCI and may help to achieve distal rewiring and favourable stent positioning against the side branch ostium, leading to reduction in ISA and potentially better clinical outcomes.

Dual-source computed tomography coronary angiography in patients with high heart rate.

Although single-source 64-multislice computed tomography coronary angiography (SSCTA) needs to reduce heart rate (HR), dual-source computed tomography coronary angiography (DSCTA) can acquire images even in tachycardia. The accuracy of DSCTA during tachycardia is compared to the accuracy of SSCTA at reduced HR. Patients who received invasive coronary angiography and either SSCTA or DSCTA were included. In the SSCTA group, HR was reduced to <65 beats per minute (bpm) with ß-blocker (n = 27), while in the DSCTA group patients whose HR was >65 bpm were selected (n = 27). The diagnostic accuracy for significant coronary stenosis was calculated by comparing the invasive coronary angiography. Using dual-Doppler echocardiography, isovolumic relaxation time (IRT) and diastasis time (DT) were evaluated in these patients. In SSCTA, sensitivity was 89 %, specificity 99 %, the positive predictive value (PPV) 94 %, and the negative predictive value (NPV) was 98 %. In DSCTA, sensitivity was 96 %, the specificity was 99 %, PPV was 91 %, and NPV was 99 % (all NS compared to SSCTA). When HR was >75 bpm, DT was markedly shortened (<83 ms), however IRT was maintained >85 ms. Thus, the image reconstruction at the phase of IRT is feasible in DSCTA because of its temporal resolution of 83 ms. High temporal resolution of DSCTA shows equivalent accuracy of coronary stenosis detection to SSCTA, without reducing heart rate, because of its image reconstruction at IRT.

Serial three-dimensional optical coherence tomography assessment of strut coverage and intraluminal structures after drug-eluting stent implantation.

Understanding of intraluminal structure and distribution of uncovered struts after drug-eluting stent implantation are limited by only 2-dimensional (2D) optical coherence tomography (OCT) images. We compared tissue coverage with 3-dimensional (3D) OCT and 2D quantitative analyses, and changes in intraluminal structure immediately after (baseline) everolimus-eluting stent (EES) implantation and at follow-up. The 2D analyses of uncovered struts ratio and tissue coverage thickness at a 0.5-mm interval were compared to 3D-OCT images and visually classified for the degree of tissue coverage. The difference in tissue coverage at baseline and follow-up after EES implantation was evaluated with tissue coverage scores (TCS) calculated by the 3D-OCT classification (Grade 0-3). 3D-OCT classifications were negatively correlated with uncovered-to-total struts (r = -0.864, P < 0.001) and positively correlated with tissue coverage thickness (r = 0.905, P < 0.001). Follow-up TCS was greater than baseline TCS (0.2 ± 0.4 vs. 1.4 ± 0.5, P < 0.001). Moreover, changes in intraluminal structures and longitudinal distribution of uncovered struts were assessed. Incomplete stent appositions, in-stent dissections, and thrombi were decreased at follow-up, indicating progressive arterial healing. The distribution of uncovered-to-total struts could be assessed by 3D-OCT, which was related to 2D analysis. Significant correlations between 3D-OCT classifications and quantitative analyses were shown. The classification and visual assessment of intraluminal structures by 3D-OCT were useful in evaluating arterial healing after EES implantation.

Japanese patients with Fabry disease predominantly showing cardiac and neurological manifestation with novel missense mutation: R220P.

BACKGROUND: Fabry disease, an X-linked lysosomal sphingolipid storage disorder caused by mutation of the α-galactosidase A (GLA) gene, results in systemic organ damage. However, the age of onset of clinical manifestations and course of the disease are variable even within the same family. OBJECTIVE: In this study, we evaluated the clinical phenotype and the molecular lesions associated with the GLA gene in a Japanese family with Fabry disease that predominantly showed cardiac and neurological manifestations. METHODS: A genetic analysis of the GLA gene using conventional genomic sequencing was performed in all seven members of this family, including four hemizygous males and three heterozygous females. Endomyocardial biopsy was performed in two patients with severe left ventricular (LV) hypertrophy. RESULTS: A novel missense mutation was identified at codon 220 in exon 5, thus resulting in an arginine to proline substitution (R220P) in all seven family members. The three adult hemizygous males had LV hypertrophy and developed neurological manifestations in their 50s. One of the adult hemizygotes developed complete atrioventricular block. On the other hand, we could not find any organ damage in a young hemizygous male or the three heterozygous females. CONCLUSION: We identified a novel missense mutation in a Japanese family with Fabry disease showing cardiac and neurological manifestations. In patients with Fabry disease, advanced organ damage in the heart and brain can be life-threatening, even if renal failure is lacking.

Low-dose ß-blocker in combination with milrinone safely improves cardiac function and eliminates pulsus alternans in patients with acute decompensated heart failure.

BACKGROUND: The purpose of this study was to determine whether a low-dose ß-blocker, in combination with milrinone, improves cardiac function in acute decompensated heart failure (ADHF) with tachycardia. METHODS AND RESULTS: Twenty ADHF patients (New York Heart Association classification III, n=1, and IV, n=19; heart rate [HR], 107±12 beats/min; left ventricular ejection fraction, 24±7%; cardiac index [CI], 2.2±0.6 L·min(-1)·m(-2); pulmonary capillary wedge pressure [PCWP], 26±8 mmHg) were enrolled in this study. The patients first underwent conventional therapy with milrinone, vasodilators and diuretics; landiolol (1.5-6.0 µg·kg(-1)·min(-1); i.v.), which is an ultra-short-acting ß(1)-selective blocker, was then added to the treatment regimen to study its effect on hemodynamics. Low-dose landiolol (1.5 µg·kg(-1)·min(-1)) significantly reduced HR by 11% without changing blood pressure (BP) and CI, whereas higher doses (≥3.0 µg·kg(-1)·min(-1)) tended to decrease BP and CI while increasing PCWP and systemic vascular resistance. After treatment with landiolol (1.5 µg·kg(-1)·min(-1)), hemodynamic parameters such as PCWP, stroke volume index, SvO(2), rate pressure product, filling time/RR, E/e', and Tei index were significantly improved. CONCLUSIONS: A low-dose ß-blocker in combination with milrinone improved cardiac function in ADHF patients with tachycardia; therefore, it may be considered as an adjunct therapy for use when standard therapy with milrinone is not effective at slowing HR.

Urinary 8-hydroxy-2'-deoxyguanosine as a novel biomarker for predicting cardiac events and evaluating the effectiveness of carvedilol treatment in patients with chronic systolic heart failure.

BACKGROUND: The authors recently reported that urinary 8-hydroxy-2'-deoxyguanosine (U8-OHdG) derived from cardiac tissue reflects clinical status and cardiac dysfunction severity in patients with chronic heart failure (CHF). The aim of the present study was to investigate whether U8-OHdG levels can accurately predict cardiac events in CHF patients and their response to ß-blocker treatment. METHODS AND RESULTS: Plasma brain natriuretic peptide (BNP) and U8-OHdG levels were measured in 186 consecutive CHF patients before discharge. Patients were then prospectively followed (median follow-up, 649 days) with endpoints of cardiac death or hospitalization due to progressive heart failure. From receiver operating characteristic curve analysis, cut-offs were 12.4ng/mg creatinine (Cr) for U8-OHdG and 207pg/ml for BNP. On multivariate Cox analysis, U8-OHdG and BNP were independent predictors of cardiac events. Patients were classified into 4 groups according to U8-OHdG and BNP cut-offs. The hazard ratio for cardiac events in patients with BNP ≥207pg/ml and U8-OHdG ≥12.4ng/mg Cr was 16.2 compared with approximately 4 for patients with only 1 indicator above its respective cut-off. Furthermore, carvedilol therapy was initiated in 30 CHF patients. In responders (≥10% increase in left ventricular ejection fraction [LVEF] or ≥1 class decrease in New York Heart Association [NYHA] class), U8-OHdG levels decreased significantly along with improved NYHA class, LVEF, and BNP levels after treatment. CONCLUSIONS: U8-OHdG may be a useful biomarker for predicting cardiac events and evaluating ß-blocker therapy effectiveness in CHF patients.

Urinary 8-hydroxy-2'-deoxyguanosine reflects symptomatic status and severity of systolic dysfunction in patients with chronic heart failure.

AIMS: Oxidative stress is known to play a crucial role in the pathogenesis of heart failure (HF). We investigated whether urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG), a product of oxidative DNA damage, is a clinically useful biomarker of the severity of chronic heart failure (CHF) and oxidative stress levels in failing hearts. METHODS AND RESULTS: We measured 8-OHdG in the serum obtained from the coronary sinus (CS) and aortic root (Ao) in small groups of control subjects and CHF patients. We then measured urinary 8-OHdG and other biomarkers (brain natriuretic peptide, 8-isoplastane, high-sensitivity C-reactive protein, interleukin-6, and tumour necrosis factor-α) in 31 control subjects and 194 patients with CHF [left-ventricular ejection fraction (LVEF): 28.3 ± 8.1%]. Serum 8-OHdG was significantly higher in the CS than the Ao in CHF patients only. Urinary 8-OHdG was also significantly higher in CHF patients than in control subjects, and urinary 8-OHdG became higher as New York Heart Association class increased. Moreover, there was a significant correlation between urinary 8-OHdG and LVEF (r = -0.27), pulmonary capillary wedge pressure (r = 0.31), or left-ventricular end-diastolic volume index (r = 0.22). In contrast, there was poor correlation between the severity of CHF and the other neurohumoral biomarkers. CONCLUSION: In HF, urinary 8-OHdG seems to reflect the level of oxidative stress and various parameters related to symptomatic status and functional severity of CHF.

Late giant coronary aneurysm associated with a fracture of sirolimus eluting stent: a case report.

A 73-year-old female underwent percutaneous coronary intervention (PCI) because of stable angina. An elective PCI for the RCA lesion was first performed with deploying sirolimus eluting stents (SES). Three weeks later, PCI was also provided in the residual LAD lesion. Eight months later, she presented with new angina. CAG revealed an in-stent restenosis in the mid LAD and a large eccentric saccular coronary aneurysm (17 mm x 9 mm) at the proximal RCA. Intravascular ultrasound (IVUS) showed absence of stent struts around the orifice of aneurysm, which suggested a fracture of SES stent. The entry of coronary aneurysm was finally sealed with a polytetrafluoroethylene-covered stent. This report documented a rare case of late giant coronary artery aneurysm associated with a fracture of SES.

Localized elevation of shear stress is related to coronary plaque rupture: a 3-dimensional intravascular ultrasound study with in-vivo color mapping of shear stress distribution.

OBJECTIVES: The purpose of the present study was to assess the relationship between shear stress distribution and coronary plaque rupture by means of a new color-mapping program of shear stress with 3-dimensional intravascular ultrasound (IVUS). BACKGROUND: Various in-vitro studies have demonstrated that shear stress of the vascular lumen is one of the important determinants of coronary plaque vulnerability. However, the in-vivo relationship between shear stress and plaque rupture is still unclear. METHODS: In the present study, 3-dimensional IVUS was used to obtain spatial information on luminal geometry from 20 patients with acute coronary syndrome having a distinct ulcerative lesion. These 3-dimensional contours for each lumen were first reconstructed into mesh polygons, and then analyzed by means of a program for calculating the fluid dynamics. The flow was considered to be a constant laminar one. Then, colorized mappings of the distribution of the streamline, blood pressure, and shear stress were performed. The original luminal contour for each ruptured lesion was obtained by smoothing and extrapolation. RESULTS: All patients had a coronary plaque rupture in the proximal or top portion of the plaque hill. In the color mapping, localized elevation of blood pressure and shear stress could be observed on each plaque surface. The shear stress concentration was frequently correlated with the plaque rupture site (kappa = 0.79). CONCLUSIONS: Although the absolute value of shear stress is not sufficient to directly provoke mechanical destruction of the fibrous cap, localized high shear stress might be a trigger of fibrous cap rupture.