Junya Ako

Local Determinants of Thrombus Formation Following Sirolimus-Eluting Stent Implantation Assessed by Optical Coherence Tomography

OBJECTIVESnWe conducted this study to assess the prevalence and determinants of subclinical thrombus after sirolimus-eluting stent (SES) implantation.nnnBACKGROUNDnAngioscopic analyses have demonstrated the presence of thrombus is more common than the clinical incidence of SES thrombosis.nnnMETHODSnFifty-three patients (53 lesions) underwent 6-month follow-up optical coherence tomography. A stent eccentricity index ([SEI] minimum/maximum stent diameter) was determined in each cross section. To evaluate unevenness of neointimal thickness, a neointimal unevenness score ([NUS] maximum neointimal thickness in the cross section/average neointimal thickness of the same cross section) was calculated for each cross section. Average SEI and NUS were calculated for each stent. Major adverse cardiac events were defined as a composite of death, myocardial infarction, and target vessel revascularization.nnnRESULTSnFourteen cases of thrombus (26%) were detected by optical coherence tomography (thrombus: n = 14 vs. nonthrombus: n = 39). The percentage of thrombus was associated with longer stents (36.4 +/- 20.2 mm vs. 25.1 +/- 9.8 mm; p = 0.008), a larger number of uncovered struts (17 +/- 16 vs. 8 +/- 11; p = 0.03), smaller average SEI (0.89 +/- 0.04 vs. 0.92 +/- 0.03; p = 0.001), and greater average NUS (2.22 +/- 0.24 vs. 2.00 +/- 0.33; p = 0.03). A significant relationship existed between average SEI and average NUS (p < 0.0001, R = 0.68), and between average SEI and the number of uncovered struts (p < 0.0006, R = 0.46). There was no significant difference in major adverse cardiac events during follow-up (median: 485 days, 7.1% vs. 12.8%; p > 0.99).nnnCONCLUSIONSnLonger stents and greater asymmetric stent expansion may be important determinants of thrombus formation after SES implantation. In this small cohort, the presence of thrombus did not increase the risk of major adverse cardiac events.

Correlation between electroencephalography and heart rate variability during sleep

Abstract It is known that autonomic nervous activities change in correspondence with sleep stages. However, the characteristics of continuous fluctuations in nocturnal autonomic nerve tone have not been clarified in detail. The study aimed to determine the possible correlation between the electroencephalogram (EEG) and autonomic nervous activities, and to clarify in detail the nocturnal fluctuations in autonomic nerve activities. Overnight EEGs and electrocardiograms of seven healthy males were obtained. These EEGs were analyzed by fast Fourier transformation algorithm to extract delta, sigma and beta power. Heart rate and heart rate variability (HRV) were calculated in consecutive 5‐min epochs. The HRV indices of low frequency (LF), high frequency (HF) and LF/HF ratio were calculated from the spectral analysis of R‐R intervals. The sleep stages were manually scored according to Rechtschaffen and Kales’ criteria. Low frequency and LF/HF were significantly lower during non‐rapid eye movement (NREM) than REM, and were lower in stages 3 and 4 than in stages 1 and 2. Furthermore, delta EEG showed inverse correlations with LF (ru2003=u2003−u20030.44, Pu2003<u20030.001) and LF/HF (ru2003=u2003−u20030.41, Pu2003<u20030.001). In contrast, HF differed neither between REM and NREM nor among NREM sleep stages. Detailed analysis revealed that correlation was evident from the first to third NREM, but not in the fourth and fifth NREM. Delta EEG power showed negative correlations with LF and LF/HF, suggesting that sympathetic nervous activities continuously fluctuate in accordance with sleep deepening and lightening.

Intravascular Ultrasound Results From the ENDEAVOR IV Trial Randomized Comparison Between Zotarolimus- and Paclitaxel-Eluting Stents in Patients With Coronary Artery Disease

OBJECTIVESnThe aim of this study was to compare the vessel response between zotarolimus-eluting stents (ZES) and paclitaxel-eluting stents (PES) using intravascular ultrasound.nnnBACKGROUNDnThe ENDEAVOR IV (Randomized Comparison of Zotarolimus- and Paclitaxel-Eluting Stents in Patients With Coronary Artery Disease) trial was a randomized controlled study of zotarolimus-eluting, phosphorylcholine-coated, cobalt-alloy stents for the treatment of de novo coronary lesions compared with using PES for the same treatment.nnnMETHODSnData were obtained from patients with serial (baseline and 8-months follow-up) intravascular ultrasound analysis available (n = 198). Volumetric analysis was performed for vessel, lumen, plaque, stent, and neointima. Cross-sectional narrowing (given as percentage) was defined as neointimal area divided by stent area. Neointima-free frame ratio was calculated as the number of frames without intravascular ultrasound-detectable neointima divided by the total number of frames within the stent. Subsegment analysis was performed at every matched 1-mm subsegment throughout the stent.nnnRESULTSnAt follow-up, the ZES group showed significantly greater percentage of neointimal obstruction (16.6 +/- 12.0% vs. 9.9 +/- 8.9%, p < 0.01) and maximum cross-sectional narrowing (31.8 +/- 16.1% vs. 25.2 +/- 14.9%, p < 0.01) with smaller minimum lumen area than the PES group did. However, the incidence of maximum cross-sectional narrowing >50% was similar in the 2 groups. Neointima-free frame ratio was significantly lower in the ZES group. In overall analysis, whereas the PES group showed positive remodeling during follow-up (13.7 +/- 4.2 mm(3)/mm to 14.3 +/- 4.3 mm(3)/mm), the ZES group showed no significant difference (12.7 +/- 3.6 mm(3)/mm to 12.9 +/- 3.5 mm(3)/mm). In subsegment analysis, significant focal positive vessel remodeling was observed in 5% of ZES and 25% of PES cases (p < 0.05).nnnCONCLUSIONSnThere were different global and focal vessel responses for ZES and PES. Both drug-eluting stents showed a similar incidence of lesions with severe narrowing despite ZES having a moderate increase in neointimal hyperplasia compared with neointimal hyperplasia in PES. There was a relatively lower neointima-free frame ratio in ZES, suggesting a greater extent of neointimal coverage. (The ENDEAVOR IV Clinical Trial: A Trial of a Coronary Stent System in Coronary Artery Lesions; NCT00217269).

Drug delivery via nano-, micro and macroporous coronary stent surfaces

Drug-eluting stents (DESs) have revolutionized the treatment of occlusive coronary artery disease via marked reduction of in-stent restenosis. One critical feature for successful DESs is the sustained release of drugs, which is achieved using a polymer coating in the present generation of DESs. However, recent studies have raised a concern that polymers may trigger allergic reactions and/or prolonged inflammation in some patients. These untoward reactions may eventually lead to undesirable clinical events, including stent thrombosis and sudden cardiac death. A new drug delivery technology, using a porous stent surface, may offer desirable drug elution properties without the use of polymers, and may translate into an improved safety profile for the next-generation DESs.

Evaluation of the peri-strut low intensity area following sirolimus- and paclitaxel-eluting stents implantation: Insights from an optical coherence tomography study in humans ☆

BACKGROUNDnRecent 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.nnnMETHODSnSeventy 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 (%).nnnRESULTSnPES 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.nnnCONCLUSIONSnThe 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.

Intraoperative Fluorescence Imaging System for On-Site Assessment of Off-Pump Coronary Artery Bypass Graft

OBJECTIVESnThe aim of this study was to evaluate the intraoperative fluorescence imaging (IFI) system in the real-time assessment of graft patency during off-pump coronary artery bypass graft.nnnBACKGROUNDnIntraoperative fluorescence imaging is an intraoperative angiography-like imaging modality using fluorescent indocyanine green excited with laser light. Recently, assessment of graft patency using the IFI system was introduced into clinical use. The feasibility and efficacy of IFI technology in off-pump coronary artery bypass graft has not been systematically compared with other conventional diagnostic modalities.nnnMETHODSnPatients undergoing off-pump coronary artery bypass graft received IFI analysis, intraoperative transit time flowmetry, and postoperative X-ray angiography. In off-line IFI analysis, the graft washout was classified based on the number of heartbeats required for indocyanine green washout: fast washout (<or=15 beats) and slow washout (>15 beats).nnnRESULTSnA total of 507 grafts in 137 patients received IFI analysis. Of all the IFI analyses, 379 (75%) grafts were visualized clearly up to the distal anastomosis. With regard to anastomosis location, anterior location was associated with a higher percentage of fully analyzable images (90%). More than 80% of images were analyzable, irrespective of graft type. Six grafts with acceptable transit time flowmetry results were diagnosed with graft failure by IFI, which required on-site graft revision. All revised grafts patency was confirmed by post-operative X-ray angiography. Conversely, 21 grafts with unsatisfactory transit time flowmetry results demonstrated acceptable patency with IFI. Graft revision was considered unnecessary in these grafts, and 20 grafts (95%) were patent by post-operative X-ray angiography. Compared with slow washout, fast washout was associated with a higher preoperative ejection fraction, use of internal mammary artery grafts, and anterior anastomosis location.nnnCONCLUSIONSnThe IFI system enables on-site assessment of graft patency, providing both morphologic and functional information. This technique may help reduce procedure-related, early graft failures in off-pump bypass patients.

Analysis of left main coronary artery bifurcation lesions treated with biolimus‐eluting DEVAX AXXESS plus nitinol self‐expanding stent: Intravascular ultrasound results of the AXXENT trial

Objective: To assess the efficacy of the AXXESS stent on the treatment of left main coronary artery (LMCA) bifurcation lesions using IVUS. Background: The treatment of LMCA bifurcation lesions remains challenging even with the use of drug‐eluting stents. The AXXESS system is a biolimus A9‐eluting self‐expanding stent, dedicated to the treatment of bifurcation lesions. Methods: Data were obtained from the AXXENT trial, a prospective, single‐arm, multicenter study designed to evaluate the efficacy of the AXXESS stent on the treatment of LMCA bifurcation lesions. IVUS was available in 26 cases at 6‐months follow‐up. Volumetric and cross‐sectional analyses within the AXXESS stent, and cross‐sectional analyses at the ostia of left anterior descending (LAD) and left circumflex coronary arteries (LCX) were performed. Results: Within the AXXESS stent, percent neointimal volume obstruction was (3.0 ± 4.1)% with a minimal lumen area of 10.3 ± 2.6 mm2. AXXESS stent volume showed an 12.4% increase at follow‐up compared with postprocedure (P = 0.04). Lumen area was significantly smaller in the LCX ostium compared with the LAD ostium at follow‐up (3.6 ± 1.3 mm2 vs. 5.5 ± 2.0 mm2, P = 0.0112). There was greater neointimal formation in the LCX ostium compared with the LAD ostium (1.37 ± 1.20 mm2 vs. 0.30 ± 0.36 mm2, P = 0.0003). Conclusions: The AXXESS stent in the LMCA showed enlargement through 6‐months follow‐up and significant neointimal suppression. Greater neointimal formation and relatively inadequate stent expansion may contribute to luminal narrowing in the LCX ostium.

SPIRIT III JAPAN Versus SPIRIT III USA: A Comparative Intravascular Ultrasound Analysis of the Everolimus-Eluting Stent

The aim of this study was to evaluate the vascular response after everolimus-eluting stent (EES) implantation in the SPIRIT III Japan Registry (JAPAN) compared to EES implantation in the SPIRIT III United States (USA) trial using serial intravascular ultrasound (IVUS) analysis. Data were obtained from the JAPAN and the randomized EES arm of the USA trial. Serial (postprocedure and 8-month follow-up) IVUS analysis was available in 199 lesions (JAPAN 82, USA 117) of 183 patients (JAPAN 73, USA 110). Although no difference was observed in vessel size in the reference segment between the 2 groups, postprocedure minimum lumen area and stent volume index were significantly greater in the JAPAN arm (minimum lumen area 5.8 +/- 2.2 vs 5.1 +/- 1.5 mm(2), p = 0.03; stent volume index 7.0 +/- 2.4 vs 6.3 +/- 1.7 mm(3)/mm, p = 0.03). Postprocedure incomplete stent apposition (ISA) was less frequently observed in the JAPAN arm (15.9% vs 33.3%, p = 0.006), possibly related to higher maximum balloon pressure and/or more postdilatation without excess tissue prolapse or edge dissection. In the JAPAN arm, percent neointimal obstruction and maximum percent cross-sectional narrowing were significantly lower at 8-month follow-up (percent neointimal obstruction 3.5 +/- 4.2% vs 6.8 +/- 6.4%, p = 0.0004). Late acquired ISA was infrequent in the 2 arms. In conclusion, comparative IVUS analysis between the JAPAN and USA arms showed more optimal stent deployment in the JAPAN arm as evidenced by the lower incidence of postprocedure ISA and larger minimum lumen area after the procedure. Moreover, there was less neointimal hyperplasia in patients with EES implants from the JAPAN arm compared to the USA arm.

Impact of acute hyperglycemia during primary stent implantation in patients with ST-elevation myocardial infarction

BACKGROUNDnAcute hyperglycemia is associated with increased mortality rates in patients with acute coronary syndrome.nnnOBJECTIVEnThis study aimed to evaluate the relationship between the glucose level and clinical variables during primary intervention in patients with ST-elevation acute myocardial infarction (STEMI).nnnMETHODS AND RESULTSnOf consecutive 94 patients with STEMI treated by primary stent implantation, acute hyperglycemia (plasma glucose level on admission>198 mg/dl) was recognized in 29 patients. There were no significant differences in baseline characteristics, except for the presence of diabetes and HbA(1c) level, between patients with and without acute hyperglycemia. In patients with acute hyperglycemia, corrected TIMI frame counts were significantly higher compared with those in patients without acute hyperglycemia (46.3+/-30.3 vs. 34.0+/-17.9, p=0.02). And corrected TIMI frame count was independently associated with plasma glucose level (p=0.006). Maximum level of creatine kinase (CK) and CK-MB were significantly higher in patients with acute hyperglycemia (CK, 4840.0+/-4690.3 vs. 2410.7+/-2302.9 IU, p=0.001; CK-MB, 315.3+/-257.7 vs. 195.9+/-191.1, p=0.01).nnnCONCLUSIONnThe presence of acute hyperglycemia was associated with the impairment of epicardial coronary flow after primary stent implantation. This mechanism might be responsible for the increased infarct size.

Tako-tsubo-like left ventricular dysfunction.

To the Editor:nnWe read with great interest the recent Images in Cardiovascular Medicine article by Girod et al1 regarding a case with tako-tsubo –like transient left ventricular dysfunction. In their article, the authors well described a case of this rather unusual disorder and also provided an impressive picture of a tako-tsubo (octopus catcher). Although the exact mechanism for this entity has yet to be …