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While primary percutaneous coronary intervention (PCI) has significantly contributed to improve the mortality in patients with ST segment elevation myocardial infarction even in cardiogenic shock, primary PCI is a standard of care in most of Japanese institutions. Whereas there are high numbers of available facilities providing primary PCI in Japan, there are no clear guidelines focusing on procedural aspect of the standardized care. Whilst updated guidelines for the management of acute myocardial infarction were recently published by European Society of Cardiology, the following major changes are indicated; (1) radial access and drug-eluting stent over bare metal stent were recommended as Class I indication, and (2) complete revascularization before hospital discharge (either immediate or staged) is now considered as Class IIa recommendation. Although the primary PCI is consistently recommended in recent and previous guidelines, the device lag from Europe, the frequent usage of coronary imaging modalities in Japan, and the difference in available medical therapy or mechanical support may prevent direct application of European guidelines to Japanese population. The Task Force on Primary Percutaneous Coronary Intervention of the Japanese Association of Cardiovascular Intervention and Therapeutics (CVIT) has now proposed the expert consensus document for the management of acute myocardial infarction focusing on procedural aspect of primary PCI.

Stent underexpansion is associated with worse outcome after stent implantation. Whether post-dilation (PD) improves outcome in patients with acute coronary syndrome (ACS) remains unclear. We performed post hoc analysis of outcome in patients from the BASE ACS (A prospective randomized comparison of titanium-nitride-oxide-coated bioactive stents with everolimus-eluting stents in acute coronary syndrome) trial who underwent PD versus those who did not. The BASE ACS trial randomized 827 patients (1:1) with ACS to receive either titanium-nitride-oxide coated bioactive stents or everolimus-eluting stents. The primary end point was major adverse cardiac events (MACE): a composite of cardiac death, nonfatal myocardial infarction (MI), or ischemia-driven target lesion revascularization. Follow-up was planned at 12 months and yearly thereafter for up to 7 years. Of 827 patients enrolled in the BASE ACS trial, 357 (43.2%) underwent PD. Median follow-up duration was 5 years. Patients who, underwent PD had less frequent nonfatal MI events at long-term follow-up, compared with those who did not (4.5% vs 8.5%, respectively, p = 0.02). The rates of MACE (15.7% vs 15.1%, respectively, p = 0.81), and the other endpoints, were not significantly different (p >0.5 for all). The results were consistent in propensity score matched analysis (270 pairs). In patients treated with bioactive stents, those who underwent PD had a trend for a fewer nonfatal MI events (p = 0.076). Comparably, in patients treated with everofimus-eluting stents, MACE and all the individual end points were comparable (p >0.5 for all). In conclusion, patients treated with early percutaneous coronary intervention for ACS who underwent PD had less frequent nonfatal MI events at long-term follow-up, compared with those who did not; MACE rates were not significantly different. (C) 2016 Elsevier Inc. All rights reserved.

Aims: The aim of this study was to compare the stent strut apposition and stent induced vessel wall stresses of currently used coronary stent designs. This may help to better understand their clinical performance and provide the insights necessary for further optimisation. Methods and results: We compared the stent strut apposition of six different stent designs when deployed (at 12 atm) in an idealised stenosed vessel using a novel approach based on finite element simulations. Additional insights into the mechanical behaviour of the investigated stents were obtained by virtually quantifying the stent induced vessel wall stresses. For the investigated stenosed vessel model, the percentage of malapposed struts (distance to wall > 10 mu m) ranged between 9% (Integrity stent) and 43% (Promus Element stent). The largest strut-artery distances were observed at the plaque shoulders. The 95 percentile of the axial stress within the intima ranges from 32 (Promus Element stent) to 83 kPa (Liberte stent). Stress peaks were mainly located at the inner curvatures of the vessel model and at the stent ends. Conclusions: For the investigated case, considerable differences were observed between the studied stent platforms in terms of stent strut apposition and stent induced vessel wall stresses. These differences in mechanical behaviour may help to explain clinical observations.

Objectives We aimed to explore the relationship of neointimal thickness (NT) to shear stress (SS) after implantation of sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES) compared with bare-metal stents (BMS). We then tested the hypothesis that drug elution attenuates the SS effect. Background Neointimal thickness after BMS implantation has been associated with SS; pertinent data for drug-eluting stents (DES) are limited. Methods Three-dimensional coronary artery and stent reconstruction was performed in 30 patients at 6-month follow-up after SES (n = 10), PES (n = 10), or BMS (n = 10) implantation. Baseline SS at the stent surface was calculated using computational fluid dynamics and NT at follow-up was computed in 3-dimensional space. Results Neointimal thickness was lower in DES versus BMS (0.03 +/- 0.07 mm vs. 0.16 +/- 0.08 mm, p < 0.001) and maximum NT was reduced in SES versus PES (0.33 +/- 0.13 mm vs. 0.46 +/- 0.13 mm, p = 0.025). In the total population, both SS (slope: -0.05 mm/Pa, p < 0.001) and DES (coefficient for DES vs. BMS: -0.17 mm, p = 0.003) were independent predictors of NT. Subgroup analysis demonstrated a significant negative relationship of NT to SS in PES (slope: -0.05 mm/Pa, p = 0.016) and BMS (slope: -0.05 mm/Pa, p = 0.001). Sirolimus elution significantly attenuated the effect of SS on NT (interaction coefficient for SES vs. BMS: 0.04 mm/Pa, p = 0.023), whereas the SS effect remained unchanged in PES (interaction coefficient for PES vs. BMS: 0.01 mm/Pa, p = 0.71). Conclusions Neointimal thickness is significantly correlated (inversely) to SS in PES as in BMS. Sirolimus elution abrogates the SS effect on the neointimal response following stent implantation, whereas the SS effect is unchanged in PES. (J Am Coll Cardiol Intv 2010;3:1181-9) (C) 2010 by the American College of Cardiology Foundation Jacc-Cardiovascular Interventions

We report a patient with coronary dilatation 10 weeks after paclitaxel-eluting stent implantation in the right coronary artery (RCA). Coronary angiography demonstrated a double-locular lumen dilatation in the body of the stented segment of the RCA, and intravascular ultrasound interrogation revealed the corresponding region with evidence of tissue regression behind the stent struts, incomplete stent apposition, and lumen enlargement. After three-dimensionally (3D) reconstructing the RCA, we applied computational fluid dynamics to the 3D RCA model, representing the lumen of the artery at the moment of stent implantation, and investigated the correlation of both neointimal thickness and tissue regression depth with shear stress in the stent. Neointimal thickness was found to be inversely related to shear stress, but there was no significant association of tissue regression depth with shear stress. Post-procedural stent malapposition, thrombus dissolution, and less possibly, a localized hypersensitivity reaction are potential mechanisms for the lumen enlargement in this case. Heart Vessels