Kunihiro Shimamura

Outcomes of everolimus-eluting stent incomplete stent apposition: a serial optical coherence tomography analysis.

AIM The aim of the present study was to evaluate the natural course of acute incomplete stent apposition (ISA) after second-generation everolimus-eluting stent (EES) when compared with first-generation sirolimus-eluting stent (SES) by using optical coherence tomography (OCT). METHODS AND RESULTS From the OCT substudy of the RESET trial, we identified 77 patients (EES = 38 and SES = 39) who successfully underwent serial OCT examination at post-stenting and 8-12-month follow-up. The presence of ISA was assessed in the OCT images, and ISA distance was measured from the centre of the strut blooming to the adjacent lumen border. Incomplete stent apposition was observed in all EES and SES at post-stenting, and it was persistent in 26% of EES and 38% of SES at 8-12-month follow-up. Maximum ISA distance was significantly decreased during the follow-up period in both EES (315 ± 94-110 ± 165 μm, P < 0.001) and SES (308 ± 119-143 ± 195 μm, P < 0.001). Receiver-operating curve analysis identified that the best cut-off value of OCT-estimated ISA distance at post-stenting for predicting late-persistent ISA at 8-12-month follow-up in EES and SES was >355 and >285 μm, respectively. CONCLUSIONS The second-generation EES showed better healing of acute ISA in comparison with the first-generation SES. Optical coherence tomography can predict late-persistent ISA after DES implantation and provide useful information to optimize PCI.

Long-Term Outcome After Deferral of Revascularization in Patients With Intermediate Coronary Stenosis and Gray-Zone Fractional Flow Reserve

BACKGROUND A strategy of deferred percutaneous coronary intervention for coronary stenosis with fractional flow reserve (FFR) 0.75-0.80, termed the gray zone, remains a matter of debate. The aim of this study was to assess the safety of deferring revascularization for patients with FFR 0.75-0.80 compared with those with FFR >0.80. METHODS AND RESULTS We assessed 3-year clinical outcome in 150 patients with angiographically intermediate stenosis who had revascularization deferred on the basis of FFR ≥ 0.75 (FFR 0.75-0.80, n=56; FFR >0.80, n=94). Target vessel failure (TVF), defined as a composite of cardiac death, target vessel-related myocardial infarction (MI), and ischemia-driven target vessel revascularization (TVR) was evaluated during follow-up. Cardiac death was observed in 1 patient with FFR 0.75-0.80. There was no target vessel-related MI in either group. The incidence of ischemia-driven TVR was higher in patients with FFR 0.75-0.80 than in those with FFR >0.80 (14% vs. 3%, P=0.020). TVF-free survival was significantly worse for the patients with FFR 0.75-0.80 than those with FFR >0.80 (hazard ratio, 5.2; 95% confidence intervals: 1.4-19.5; P=0.015). CONCLUSIONS Patients with FFR 0.75-0.80 were at higher risk of TVF mainly due to TVR than those with FFR >0.80.

Impact of Eicosapentaenoic Acid Treatment on the Fibrous Cap Thickness in Patients with Coronary Atherosclerotic Plaque: An Optical Coherence Tomography Study

AIM Previous clinical trials have demonstrated the effectiveness of eicosapentaenoic acid (EPA) in preventing cardiovascular events. The aim of the present study was to investigate the effects of EPA treatment on the accumulation of coronary atherosclerotic plaque using optical coherence tomography (OCT). METHODS A total of 46 acute coronary syndrome (ACS) patients without dyslipidemia were divided into two groups: those who received 1,800 mg/day of EPA (n = 15) or the control group (n = 31). Serial OCT examinations were performed at baseline and after eight months of follow-up. The target for the OCT analysis was non-culprit plaque with a percent diameter of stenosis of 30% to 70% in non-culprit vessels of ACS. RESULTS Between the baseline and follow-up visits, the serum EPA levels increased (50 ± 26 mg/dL to 200 ± 41 mg/dL, p ＜ 0.001) in the EPA group, although they did not change in the control group. According to the OCT analysis, the lipid arc did not change in the EPA group (131 ± 52 degrees to 126 ± 54 degrees, p = 0.106) or the control group (137 ± 50 degrees to 138 ± 50 degrees, p=0.603). In contrast, the fibrous cap thickness significantly increased in both the EPA group (169 ± 70 μm to 201 ± 49 μm, p ＜ 0.001) and the control group (164 ± 63 μm to 174 ± 72 μm, p=0.018); however, the relative change in the fibrous cap thickness was significantly greater in the EPA group than in the control group (131 ± 35% vs. 106 ± 15%, p = 0.001). CONCLUSIONS In the present study, the administration of EPA for eight months significantly increased the fibrous cap thickness in patients with coronary atherosclerotic plaque.

Prognostic Value of Microvascular Resistance Index Immediately After Primary Percutaneous Coronary Intervention on Left Ventricular Remodeling in Patients With Reperfused Anterior Acute ST-Segment Elevation Myocardial Infarction

OBJECTIVES This study sought to investigate the relationship between the degree of microvascular dysfunction assessed by a dual-sensor guidewire (pressure and Doppler velocity) and left ventricular (LV) remodeling after successful primary percutaneous coronary intervention (PPCI) for a first anterior acute myocardial infarction (AMI). BACKGROUND Microvascular dysfunction after AMI is associated with progressive LV dilation. METHODS In 24 consecutive patients, the microvascular resistance index (MVRI) immediately after PPCI was calculated as the ratio of the mean distal pressure to average peak flow velocity during maximal hyperemia. Cardiac magnetic resonance was performed to determine LV volumes at baseline and 8-month follow-up. LV remodeling was defined as an increase in left ventricular end-diastolic volume (LVEDV) of ≥20%. RESULTS In patients with an MVRI greater than the median value of 2.96 mm Hg·cm(-1)·s, the LVEDV increased significantly from 117.1 ± 20.7 ml at baseline to 146.5 ± 21.4 ml (p = 0.006) at 8 months, whereas it did not change between baseline and 8 months (108.2 ± 21.2 ml vs. 111.6 ± 29.9 ml, p = 0.620) in patients with an MVRI ≤2.96 mm Hg·cm(-1)·s. LV remodeling was more frequent in the group with an MVRI >2.96 mm Hg·cm(-1)·s (64% vs. 15%, p = 0.033). Furthermore, there was a positive correlation between MVRI and the percentage of increase or decrease in LVEDV (r = 0.42, p = 0.042). Logistic regression analysis showed that MVRI was the strongest univariate predictor of LV remodeling. The best cutoff value of MVRI was 2.96 mm Hg·cm(-1)·s with a sensitivity of 78% and a specificity of 73%. CONCLUSIONS MVRI immediately after PPCI predicts LV remodeling in patients with reperfused anterior AMI.

Effect of strut thickness on neointimal atherosclerotic change over an extended follow-up period (≥ 4 years) after bare-metal stent implantation: intracoronary optical coherence tomography examination.

BACKGROUND Neointima inside the bare-metal stents (BMSs) can transform into atherosclerotic tissue during an extended follow-up because of a persistent inflammatory reaction to the metal. We sought to investigate whether strut thickness may impact on the atherosclerotic change in neointima 4 years or more after BMS implantation using optical coherence tomography. METHODS Forty-six stented lesions of 41 patients with BMS ≥ 4 years after implantation who underwent optical coherence tomography were enrolled in the study. The strut was defined as thin when less than 100 μm and thick when ≥ 100 μm. According to these criteria, stents were divided into 2 groups (thin strut n = 19, thick strut n = 27). Neointimal tissue was categorized into normal neointima, characterized by a signal-rich band without signal attenuation, or lipid-laden intima, with marked signal attenuation and a diffuse border. Intimal disruption, thrombus, and neovascularization were also evaluated. RESULTS The mean period after implantation was 98.2 ± 25.8 months in the thin-strut group and 91.1 ± 22.8 months in the thick-strut group (P = .330). Lipid-laden intima (70% vs 32%, P = .016), thin-cap fibroatheroma-like intima (59% vs 16%, P = .0056), and intimal disruption (48% vs 16%, P = .031) were observed more frequently in the thick-strut group than in the thin-strut group, but no significant difference was observed in the frequency of thrombus. Although peristrut neovascularization was a common finding in both groups (thick vs thin 81% vs 79%, P = 1.000), the frequency of intraintima neovascularization tended to be higher in the thick-strut group (67% vs 42%, P = .135). CONCLUSIONS A thinner strut thickness may have favorable effects on neointimal atherosclerotic changes after BMS implantation.

Impact of glucose fluctuation and monocyte subsets on coronary plaque rupture

BACKGROUND AND AIMS It remains unclear whether glycemic fluctuation can affect plaque rupture in acute myocardial infarction (AMI). Here we investigate the impact of glucose fluctuation on plaque rupture, as observed by optical coherence tomography (OCT), and monocyte subsets in patients with AMI. METHODS AND RESULTS We studied 37 consecutive patients with AMI. All patients underwent OCT examination, which revealed 24 patients with plaque rupture and 13 patients without plaque rupture at the culprit site. Peripheral blood sampling was performed on admission. Three monocyte subsets (CD14(+)CD16(-), CD14(bright)CD16(+), and CD14(dim)CD16(+)) were assessed by flow cytometry. Glycemic variability, expressed as the mean amplitude of glycemic excursion (MAGE), was determined by a continuous glucose monitoring system 7 days after the onset of AMI. MAGE was significantly higher in the rupture patients than in the non-rupture patients (P=0.036). Levels of CD14(bright)CD16(+) monocytes from the rupture patients were significantly higher than those from the non-rupture patients (P=0.042). Of interest, levels of CD14(bright)CD16(+) monocytes correlated positively and significantly with MAGE (r=0.39, P=0.02). CONCLUSION Dynamic glucose fluctuation may be associated with coronary plaque rupture, possibly through the preferential increase in CD14(bright)CD16(+) monocyte levels.

Optical Coherence Tomography Predictors for Edge Restenosis After Everolimus-Eluting Stent Implantation

Background—Stent edge restenosis (SER) remains a potential limitation of drug-eluting stents. The aim of this study was to determine optical coherence tomography (OCT) predictors for angiographic late SER after everolimus-eluting stent implantation. Methods and Results—We retrospectively analyzed 319 patients who underwent OCT immediately after everolimus-eluting stent implantation and scheduled 9- to 12-month follow-up angiography. The binary angiographic SER rate was 10% (32/319) in the patients, 8.4% (32/382) in lesions, and 4.4% (33/744) in stent edge segments. In the stent edge segments at post stenting, OCT-derived lipidic plaque (61% versus 20%; P<0.001) was more often observed in the SER group, and OCT-measured minimum lumen area (4.13±2.61 versus 5.58±2.46 mm2; P=0.001) was significantly smaller in the SER group compared with the non-SER group. Multivariate analysis identified lipidic plaque (odds ratio: 5.99; 95% confidence interval: 2.89–12.81; P<0.001) and minimum lumen area (odds ratio: 0.64; 95% confidence interval: 0.42–0.96; P=0.029) as independent predictors of binary SER. Receiver-operating characteristic analysis demonstrated that lipid arc of 185° (sensitivity: 71%; specificity: 72%; area under the curve: 0.761) and minimum lumen area of 4.10 mm2 (sensitivity: 67%; specificity: 77%; area under the curve: 0.787) were optimal cutoff values for predicting ischemia-driven SER. Conclusions—The present OCT study demonstrated that lipidic plaque and minimum lumen area in the stent edge segments at post stenting were associated with late SER after everolimus-eluting stent implantation. OCT provides valuable information to determine an appropriate landing zone for stent implantation.

Impact of myocardial supply area on the transstenotic hemodynamics as determined by fractional flow reserve

The aim of this study was to investigate the impact of myocardial area supplied by the coronary artery on fractional flow reserve (FFR).

Difference in neointimal appearance between early and late restenosis after sirolimus-eluting stent implantation assessed by optical coherence tomography.

ObjectivesLate in-stent restenosis (ISR) is an important clinical issue in the drug-eluting stent era. Autopsy studies have reported different underlying mechanisms between early ISR and late ISR. The aim of the present study was to compare the neointimal tissue appearance between early ISR (<1 year) and late ISR (>1 year) after sirolimus-eluting stent (SES) implantation using optical coherence tomography (OCT). Materials and methodsWe examined the neointimal tissue appearance in 48 ISR lesions after SES implantation [30 early ISR lesions (8±1 months after stenting) and 18 late ISR lesions (34±14 months after stenting)] by OCT. ISR was defined as percent diameter stenosis more than 50% within the stented segment in angiography. Lipid-rich neointima was characterized by signal-poor regions with diffuse borders. Thin-cap fibroatheroma (TCFA)-like neointima was defined by lipid-rich neointima with cap thickness 65 &mgr;m or less. ResultsIn the OCT findings, heterogeneous neointima was more often observed in the late ISR group compared with the early ISR group (89 vs. 43%, P=0.002). Although the frequency of intraluminal thrombus was not different between the two groups (P=0.085), the frequency of lipid-rich neointima (83 vs. 27%, P<0.001), TCFA-like neointima (39 vs. 10%, P=0.028), microchannels within neointima (67 vs. 27%, P=0.007), and neointimal disruption (33 vs. 3%, P=0.008) was significantly higher in the late ISR group. ConclusionIn the present OCT study, it was found that atherosclerotic progression of neointima, such as lipid-rich neointima, TCFA-like neointima, microchannels, and neointimal disruption, was more often observed in late ISR lesions after SES implantation compared with early ISR ones.

Improvement of Cardiac Function by Increasing Stimulus Strength During Left Ventricular Pacing in Cardiac Resynchronization Therapy

Cardiac resynchronization therapy (CRT) is an established therapy in patients with severe heart failure due to left ventricular (LV) dyssynchrony. Increasing stimulus strength (SS) of LV pacing could capture an enlarged myocardial area and provide rapid electrical conduction. The aim of the present study was to investigate whether increasing SS of LV pacing improves LV mechanical dyssynchrony and cardiac function in patients treated with CRT.We enrolled 26 patients with CRT and changed the SS of LV pacing: 2.5 V (standard SS) and 5 V (high SS). Electrocardiography and echocardiography were performed to assess QRS duration, LV mechanical dyssynchrony, and cardiac function under each condition.The QRS duration (138.6 ± 21.4 ms versus 126.8 ± 23.1 ms, P < 0.001), septal-posterior wall motion delay (126.5 ± 42.7 ms versus 111.4 ± 55.3 ms, P = 0.012), standard deviation of time from QRS (69.6 ± 21.8 ms versus 55.6 ± 19.4 ms, P < 0.001), LV ejection fraction (29.4 ± 10.6% versus 33.4 ± 11.6%, P = 0.005), and LV stroke volume (50.7 ± 15.5 mL versus 63.8 ± 18.3 mL, P < 0.001) improved significantly in high SS compared with standard SS.Increasing SS of LV pacing in CRT improves LV mechanical dyssynchrony and cardiac function. The capture of an enlarged myocardial area by increasing SS of LV pacing might offer an acute hemodynamic benefit to patients treated with CRT.