Takashi Muramatsu

Background First generation drug-eluting stents (DES) were associated with a high incidence of late stent thrombosis (ST), mainly due to delayed healing and re-endothelization by the durable polymer coating. This study sought to assess the safety and efficacy of the Nano polymer-free sirolimus-eluting stent (SES) in the treatment of patients with de novo coronary artery lesions. Methods The Nano trial is the first randomized trial designed to compare the safety and efficacy of the Nano polymer-free SES and Partner durable-polymer SES (Lepu Medical Technology, Beijing, China) in the treatment of patients with de novo native coronary lesions. The primary endpoint was in-stent late lumen loss (LLL) at 9-month follow-up. The secondary endpoint was major adverse cardiac events (MACE), a composite of cardiac death, myocardial infarction or target lesion revascularization. Results A total of 291 patients (Nano group: n=143, Partner group: n=148) were enrolled in this trial from 19 Chinese centers. The Nano polymer-free SES was non-inferior to the Partner durable-polymer DES at the primary endpoint of 9 months (P <0.001). The 9-month in-segment LLL of the polymer-free Nano SES was comparable to the Partner SES (0.34 +/- 0.42) mm vs. (0.30 +/- 0.48) mm, P=0.21). The incidence of MACE in the Nano group were 7.6% compared to the Partner group of 5.9% (P=0.75) at 2 years follow-up. The frequency of cardiac death and stent thrombosis was low for both Nano and Partner SES (0.8% vs. 0.7%, 0.8% vs. 1.5%, both P=1.00). Conclusions In this multicenter randomized Nano trial, the Nano polymer-free SES showed similar safety and efficacy compared with the Partner SES in the treatment of patients with de novo coronary artery lesions. Trials in patients with complex lesions and longer term follow-up are necessary to confirm the clinical performance of this novel Nano polymer-free SES.

Background Drug eluting stents (DESs) made with biodegradable polymer have been developed in an attempt to improve clinical outcomes. However, the impact of biodegradable polymers on clinical events and stent thrombosis (ST) remains controversial. Methods We searched Medline, the Cochrane Library and other internet sources, without language or date restrictions for articles comparing clinical outcomes between biodegradable polymer DES and durable polymer DES. Safety endpoints were ST (definite, definite/probable), mortality, and myocardial infarction (MI). Efficacy endpoints were major adverse cardiac event (MACE) and target lesion revascularization (TLR). Results We identified 15 randomized controlled trials (n=17 068) with a weighted mean follow-up of 20.6 months. There was no statistical difference in the incidence of definite/probable ST between durable polymer- and biodegradable polymer-DES; relative risk (RR) 0.83; 95% confidence interval (CI) 0.62-1.11; P=0.22. Biodegradable polymer DES had similar rates of definite ST (RR 0.94, 95% CI 0.66-1.33, P=0.72), mortality (RR 0.94, 95% CI 0.82-1.09, P=0.43), MI (RR 1.08, 95% CI 0.92-1.26. P=0.35), MACE (RR 0.99, 95% CI 0.91-1.09, P=0.85), and TLR (RR, 0.94, 95% CI 0.83-1.06, P=0.30) compared with durable polymer DES. Based on the stratified analysis of the included trials, the treatment effect on definite ST was different at different follow-up times: year favoring durable polymer DES and >1 year favoring biodegradable polymer DES. Conclusions Biodegradable polymer DES has similar safety and efficacy for treating patients with coronary artery disease compared with durable polymer DES. Further data with longer term follow-up are warranted to confirm the potential benefits of biodegradable polymer DES.

Objectives The aim of this study was to evaluate 1-year clinical outcomes of diabetic patients treated with the Absorb bioresorbable vascular scaffold (BVS). Background Clinical outcomes of diabetic patients after BVS implantation have been unreported. Methods This study included 101 patients in the ABSORB Cohort B trial and the first consecutive 450 patients with 1 year of follow-up in the ABSORB EXTEND trial. A total of 136 diabetic patients were compared with 415 nondiabetic patients. In addition, 882 diabetic patients treated with everolimuseluting metal stents (EES) in pooled data from the SPIRIT trials (SPIRIT FIRST [Clinical Trial of the Abbott Vascular XIENCE V Everolimus Eluting Coronary Stent System], SPIRIT II [A Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System], SPIRIT III [Clinical Trial of the XIENCE V Everolimus Eluting Coronary Stent System (EECSS)], SPIRIT IV Clinical Trial [Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System]) were used for the comparison by applying propensity score matching. The primary endpoint was a device-oriented composite endpoint (DoCE), including cardiac death, target vessel myocardial infarction, and target lesion revascularization at 1-year follow-up. Results The cumulative incidence of DoCE did not differ between diabetic and nondiabetic patients treated with the BVS (3.7% vs. 5.1%, p = 0.64). Diabetic patients treated with the BVS had a similar incidence of the DoCE compared with diabetic patients treated with EES in the matched study group (3.9% for the BVS vs. 6.4% for EES, p = 0.38). There were no differences in the incidence of definite or probable scaffold/stent thrombosis (0.7% for both diabetic and nondiabetic patients with the BVS; 1.0% for diabetic patients with the BVS vs. 1.7% for diabetic patients with EES in the matched study group). Conclusions In the present analyses, diabetic patients treated with the BVS showed similar rates of DoCEs compared with nondiabetic patients treated with the BVS and diabetic patients treated with EES at 1-year follow-up. (ABSORB Clinical Investigation, Cohort B; NCT00856856; ABSORB EXTEND Clinical Investigation; NCT01023789; Clinical Trial of the Abbott Vascular XIENCE V Everolimus Eluting Coronary Stent System [SPIRIT FIRST]; NCT00180453; A Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System [SPIRIT II]; NCT00180310; Clinical Trial of the XIENCE V Everolimus Eluting Coronary Stent System [EECSS] [SPIRIT III]; NCT00180479; Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System [SPIRIT IV Clinical Trial]; NCT00307047). (C) 2014 by the American College of Cardiology Foundation

Objectives The purpose of this study was to assess the occurrence, predictors, and mechanisms of optical coherence tomography (OCT)-detected coronary evaginations following drug-eluting stent (DES) implantation. Background Angiographic ectasias and aneurysms in stented segments have been associated with a risk of late stent thrombosis. Using OCT, some stented segments show coronary evaginations reminiscent of ectasias. Methods Evaginations were defined as outward bulges in the luminal contour between struts. They were considered major evaginations (MEs) when extending >= 3 mm along the vessel length, with a depth >= 10% of the stent diameter. A total of 228 patients who had sirolimus (SES)-, paclitaxel-, biolimus-, everolimus (EES)-, or zotarolimus (ZES)-eluting stents implanted in 254 lesions, were analysed after 1, 2, or 5 years; and serial assessment using OCT and intravascular ultrasound (IVUS) was performed post-intervention and after 1 year in 42 patients. Results Major evaginations occurred frequently at all time points in SES (similar to 26%) and were rarely seen in EES (3%) and ZES (2%, P = 0.003). Sirolimus-eluting stent implantation was the strongest independent predictor of ME [adjusted OR (95% CI) 9.1 (1.1-77.4), P = 0.008]. Malapposed and uncovered struts were more common in lesions with vs. without ME (77 vs. 25%, P < 0.001 and 95 vs. 20%, P < 0.001, respectively) as was thrombus [49 vs. 14%, OR 7.3 (95% CI: 1.7-31.2), P = 0.007]. Post-intervention intra-stent dissection and protrusion of the vessel wall into the lumen were associated with an increased risk of evagination at follow-up [OR (95% CI): 2.9 (1.8-4.9), P < 0.001 and 3.3 (1.6-6.9), P = 0.001, respectively]. In paired IVUS analyses, lesions with ME showed a larger increase in the external elastic membrane area (20% area change) compared with lesions without ME (5% area change, P < 0.001). Conclusion Optical coherence tomography-detected MEs are a specific morphological footprint of early-generation SES and are nearly absent in newer-generation ZES and EES. Evaginations appear to be related to vessel injury at baseline; are associated with positive vessel remodelling; and correlate with uncoverage, malapposition, and thrombus at follow-up.

Aims We evaluated the feasibility and the acute performance of the everolimus-eluting bioresorbable vascular scaffolds (BVS) for the treatment of patients presenting with ST-segment elevation myocardial infarction (STEMI). Methods and results The present investigation is a prospective, single-arm, single-centre study, reporting data after the BVS implantation in STEMI patients. Quantitative coronary angiography and optical coherence tomography (OCT) data were evaluated. Clinical outcomes are reported at the 30-day follow-up. The intent-to-treat population comprises a total of 49 patients. The procedural success was 97.9%. Pre-procedure TIMI-flow was 0 in 50.0% of the patients; after the BVS implantation, a TIMI-flow III was achieved in 91.7% of patients and the post-procedure percentage diameter stenosis was 14.7+/-8.2%. No patients had angiographically visible residual thrombus at the end of the procedure. Optical coherence tomography analysis performed in 31 patients showed that the post-procedure mean lumen area was 8.02+/-1.92 mm(2), minimum lumen area 5.95+/-1.61 mm(2), mean incomplete scaffold apposition area 0.118+/-0.162 mm(2), mean intraluminal defect area 0.013+/-0.017 mm(2), and mean percentage malapposed struts per patient 2.80+/-3.90%. Scaffolds with >5% malapposed struts were 7. At the 30-day follow-up, target-lesion failure rate was 0%. Non-target-vessel revascularization and target-vessel myocardial infarction (MI) were reported. Anon-target-vessel non-Q-wave MI occurred. No cases of cardiac death or scaffold thrombosis were observed. Conclusion In the present series, the BVS implantation in patients presenting with acute MI appeared feasible, with high rate of final TIMI-flow III and good scaffold apposition. Larger studies are currently needed to confirm these preliminary data.

Background Metallic stents change permanently the mechanical properties of the vessel wall. However little is known about the implications of bioresorbable vascular scaffolds (BVS) on the vessel wall strain. Methods Patients (n = 53) implanted with an Absorb BVS that had palpographic evaluation at any time point [before device implantation, immediate after treatment, at short-term (6-12 months) or mid-term follow-up (24-36 months)] were included in the current analysis. The palpographic data were used to estimate the mean of the maximum strain values and the obtained measurements were classified using the Rotterdam classification (ROC) score and expressed as ROC/mm. Results Scaffold implantation led to a significant decrease of the vessel wall strain in the treated segment [0.35 (0.20, 0.38) vs. 0.19 (0.09, 0.29); P = 0.005] but it did not affect the proximal and distal edge. In patients who had serial palpographic examination the vessel wall strain continued to decrease in the scaffolded segment at short-term [0.20 (0.12, 0.29) vs. 0.14 (0.08, 0.20); P = 0.048] and mid-term follow-up [0.20 (0.12, 0.29) vs. 0.15 (0.10, 0.19), P = 0.024]. No changes were noted with time in the mechanical properties of the vessel wall at the proximal and distal edge. Conclusions Absorb BVS implantation results in a permanent alteration of the mechanical properties of the vessel wall in the treated segment. Long term follow-up data are needed in order to examine the clinical implications of these findings.

Aims: To assess observations with multimodality imaging of the Absorb bioresorbable everolimus-eluting vascular scaffold performed in two consecutive cohorts of patients who were serially investigated either at 6 and 24 months or at 12 and 36 months. Methods and results: In the ABSORB multicentre single-arm trial, 45 patients (cohort B1) and 56 patients (cohort B2) underwent serial invasive imaging, specifically quantitative coronary angiography (QCA), intravascular ultrasound (IVUS), radiofrequency backscattering (IVUS-VH) and optical coherence tomography (OCT). Between one and three years, late luminal loss remained unchanged (6 months: 0.19 mm, 1 year: 0.27 mm, 2 years: 0.27 mm, 3 years: 0.29 mm) and the in-segment angiographic restenosis rate for the entire cohort B (n=101) at three years was 6%. On IVUS, mean lumen, scaffold, plaque and vessel area showed enlargement up to two years. Mean lumen and scaffold area remained stable between two and three years whereas significant reduction in plaque behind the struts occurred with a trend toward adaptive restrictive remodelling of EEM. Hyperechogenicity of the vessel wall, a surrogate of the bioresorption process, decreased from 23.1% to 10.4% with a reduction of radiofrequency backscattering for dense calcium and necrotic core. At three years, the count of strut cores detected on OCT increased significantly, probably reflecting the dismantling of the scaffold; 98% of struts were covered. In the entire cohort B (n=101), the three-year major adverse cardiac event rate was 10.0% without any scaffold thrombosis. Conclusions: The current investigation demonstrated the dynamics of vessel wall changes after implantation of a bioresorbable scaffold, resulting at three years in stable luminal dimensions, a low restenosis rate and a low clinical major adverse cardiac events rate. Clinical Trial Registration Information: http://www.clinicaltrials.gov/ct2/show/NCT00856856

Intravascular ultrasound (IVUS)-based reconstructions have been traditionally used to examine the effect of endothelial shear stress (ESS) on neointimal formation. The aim of this analysis is to compare the association between ESS and neointimal thickness (NT) in models obtained by the fusion of optical coherence tomography (OCT) and coronary angiography and in the reconstructions derived by the integration of IVUS and coronary angiography. We analyzed data from six patients implanted with an Absorb bioresorbable vascular scaffold that had biplane angiography, IVUS and OCT investigation at baseline and 6 or 12 months follow-up. The IVUS and OCT follow-up data were fused separately with the angiographic data to reconstruct the luminal morphology at baseline and follow-up. Blood flow simulation was performed on the baseline reconstructions and the ESS was related to NT. In the OCT-based reconstructions the ESS were lower compared to the IVUS-based models (1.29 +/- A 0.66 vs. 1.87 +/- A 0.66 Pa, P = 0.030). An inverse correlation was noted between the logarithmic transformed ESS and the measured NT in all the OCT-based models which was higher than the correlation reported in five of the six IVUS-derived models (-0.52 +/- A 0.19 Pa vs. -0.10 +/- A 0.04, P = 0.028). Fusion of OCT and coronary angiography appears superior to IVUS-based reconstructions; therefore it should be the method of choice for the study of the effect of the ESS on neointimal proliferation.

Objectives This study sought to investigate the effect of endothelial shear stress (ESS) on neointimal formation following an Absorb bioresorbable vascular scaffold (BVS) (Abbott Vascular, Santa Clara, California) implantation. Background Cumulative evidence, derived from intravascular ultrasound-based studies, has demonstrated a strong association between local ESS patterns and neointimal formation in bare-metal stents, whereas in drug-eluting stents, there are contradictory data about the effect of ESS on the vessel wall healing process. The effect of ESS on neointimal development following a bioresorbable scaffold implantation remains unclear. Methods Twelve patients with an obstructive lesion in a relatively straight arterial segment, who were treated with an Absorb BVS and had serial optical coherence tomographic examination at baseline and 1-year follow-up, were included in the current analysis. The optical coherence tomographic data acquired at follow-up were used to reconstruct the scaffolded segment. Blood flow simulation was performed on the luminal surface at baseline defined by the Absorb BVS struts, and the computed ESS was related to the neointima thickness measured at 1-year follow-up. Results At baseline, the scaffolded segments were exposed to a predominantly low ESS environment (61% of the measured ESS was <1 Pa). At follow-up, the mean neointima thickness was 113 +/- 45 mu m, whereas the percentage scaffold volume obstruction was 13.1 +/- 6.6%. A statistically significant inverse correlation was noted between baseline logarithmic transformed ESS and neointima thickness at 1-year follow-up in all studied segments (correlation coefficient range -0.140 to -0.662). Mixed linear regression analysis between baseline logarithmic transformed ESS and neointima thickness at follow-up yielded a slope of -31 mu m/ln(Pa) and a y-intercept of 99 mu m. Conclusions The hemodynamic microenvironment appears to regulate neointimal response following an Absorb BVS implantation. These findings underline the role of the ESS patterns on vessel wall healing and should be taken into consideration in the design of bioresorbable devices. (C) 2014 by the American College of Cardiology Foundation

Aims: Angiographic evidence of edge dissections has been associated with a risk of early stent thrombosis. Optical coherence tomography (OCT) is a high-resolution technology detecting a greater number of edge dissections particularly non-flow-limiting compared to angiography. Their natural history and clinical implications remain unclear. The objectives of the present study were to assess the morphology, healing response, and clinical outcomes of OCT-detected edge dissections using serial OCT imaging at baseline and at one year following drug-eluting stent (DES) implantation. Methods and results: Edge dissections were defined as disruptions of the luminal surface in the 5 mm segments proximal and distal to the stent, and categorised as flaps, cavities, double-lumen dissections or fissures. Qualitative and quantitative OCT analyses were performed every 0.5 mm at baseline and one year, and clinical outcomes were assessed. Sixty-three lesions (57 patients) were studied with OCT at baseline and one-year follow-up. Twenty-two non-flow-limiting edge dissections in 21 lesions (20 patients) were identified by OCT; only two (9%) were angiographically visible. Flaps were found in 96% of cases. The median longitudinal dissection length was 2.9 mm (interquartile range [IQR] 1.6-4.2 mm), whereas the circumferential and axial extensions amounted to 1.2 mm (IQR: 0.9-1.7 mm) and 0.6 mm (IQR: 0.4-0.7 mm), respectively. Dissections extended into the media and adventitia in seven (33%) and four (20%) cases, respectively. Eighteen (82%) OCT-detected edge dissections were also evaluated with intravascular ultrasound which identified nine (50%) of these OCT-detected dissections. No stent thrombosis or target lesion revascularisation occurred up to one year. At follow-up, 20 (90%) edge dissections were completely healed on OCT. The two cases exhibiting persistent dissection had the longest flaps (2.81 mm and 2.42 mm) at baseline. Conclusions: OCT-detected edge dissections which are angiographically silent in the majority of cases are not associated with acute stent thrombosis or restenosis up to one-year follow-up.

The introduction of metallic drug-eluting stents has reduced the risk of restenosis and widened the indications of percutaneous coronary intervention in treatment of coronary artery disease. However, this medical device can induce hypersensitive reaction that interferes with the endothelialization and healing process resulting in late persistent or acquired malapposition of the permanent metallic implant. Delayed endotheliaization and malapposition may lead to late and very late stent thrombosis. Bioresorbable scaffolds (BRS) have been introduced to potentially overcome these limitations, as they provide temporary scaffolding and then disappear, liberating the treated vessel from its cage. Magnesium is an essential mineral needed for a variety of physiological functions in the human body and its bioresorbable alloy has the strength-to-weight ratio comparable with that of strong aluminum alloys and alloy steels. The aim of this review is to present the new developments in Magnesium BRS technology, to describe its clinical application and to discuss the future prospects of this innovative therapy. © 2013 by the authors licensee MDPI, Basel, Switzerland.

Recently, we reported that angiotensin II receptor blocker (ARB), valsartan, and calcium channel blocker (CCB), amlodipine, had similar effects on the prevention of cardiovascular disease (CVD) events in diabetic hypertensive patients. We assessed the difference of. cardiovascular protective effects between ARB and CCB in patients with and without previous CVD, respectively. A total of 1,150 Japanese diabetic hypertensive patients were randomized to either valsartan or amlodipine treatment arms, which were additionally divided into 2 groups according to the presence of previous CVD at baseline (without CVD, n = 818; with CVD, n = 332). The primary composite outcomes were sudden cardiac death, acute myocardial infarction, stroke, coronary revascularization, or hospitalization for heart failure. The incidence of primary end point events in patients with previous CVD was 3.5-times greater than that in patients without previous CVD (64.1 vs 17.9/1,000 person-years). The ARB- and the CCB-based treatment arms showed similar incidence of composite CVD events in both patients without previous CVD (hazard ratio [BR] 1.35, 95% confidence interval [CI] 0.76 to 2.40) and those with previous CVD (HR 0.79, 95% CI 0.48 to 1.31). The ARB-treatment arm showed less incidence of stroke compared with the CCB-based treatment arm in patients with previous CVD (HR 0.24, 95% CI 0.05 to 1.11, p = 0.068), whereas the 2 treatment arms showed similar incidence of stroke in patients without previous CVD (HR 1.52, 95% CI 0.59 to 3.91). In conclusion, the ARE- and the CCB-based treatments exerted similar protective effects of CVD events regardless of the presence of previous CVD. For stroke events, the ARB may have more protective effects than the CCB in diabetic hypertensive patients with previous CVD. (C) 2013 Elsevier Inc. All rights reserved.

OBJECTIVES This study sought to determine the clinical and angiographic variables that would identify patients with high-risk "vulnerable" coronary plaques. BACKGROUND In the PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree) study, in patients successfully treated for acute coronary syndrome (ACS), plaque composition, plaque burden, and minimal lumina] area as detected by 3-vessel radiofrequency intravascular ultrasound (IVUS) imaging were associated with an increased risk of developing future events from untreated atherosclerotic lesions (vulnerable plaques). Whether baseline demographic and angiographic findings can be used to identify patients most likely to have vulnerable coronary plaques has not been examined. METHODS On the basis of 3-vessel radiofrequency IVUS imaging, patents in the PROSPECT trial were classified in 2 groups according to whether or not one or more untreated high-risk plaques were present, defined as having >= 2 high-risk features (a thin-cap fibroatheroma, plaque burden >= 70%, and/or minimal luminal area <= 4 mm(2)). RESULTS The high-risk group (those with one or more high-risk lesions) had higher Framingham risk score (7.5 +/- 3.4 vs. 6.9 +/- 3.3; p = 0.04), more extensive coronary artery disease, and more nonculprit lesion related cardiovascular events during the 3-year follow-up (hazard ratio: 2.63; 95% confidence interval: 1.62 to 3.66; p < 0.0001). However, demographic factors had poor discrimination in detecting high-risk patients (area under the curve 0.55), and discrimination was only slightly improved when angiographic variables were entered into the model (area under the curve 0.64). CONCLUSIONS Clinical and angiographic characteristics had poor predictive accuracy in identifying patients with untreated high-risk plaques related to future adverse events. This finding highlights the potential value of comprehensive 3-vessel imaging assessment (either invasive or noninvasive) to evaluate plaque phenotype for more accurate risk stratification of patients admitted with ACS. (C) 2013 by the American College of Cardiology Foundation

Objectives This study sought to investigate the impact of left main coronary artery (LMCA) 3-dimensional (3D) bifurcation angle (BA) parameters on 5-year clinical outcomes of patients randomized to LMCA percutaneous coronary intervention (PCI) in the SYNTAX (Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery) trial. Background BA can affect outcome after bifurcation PCI; 3D angiographic analysis provides reliable BA measurements. Methods The diastolic distal BA (between left anterior descending and left circumflex) and its systolic-diastolic range were explored. A stratified post-hoc survival analysis was performed for 5-year major adverse cardiac and cardiovascular events (MACCE) (all-cause death, cerebrovascular accident, myocardial infarction, or repeat revascularization), a safety endpoint (all-cause death, cerebrovascular accident, or myocardial infarction), and repeat revascularization. Analysis was performed in patients where 3D BA was available pre- and post-PCI. Results Of 266 patients eligible for analysis, 185 underwent bifurcation PCI (group B); 1 stent was used in 75 patients (group B1), whereas >= 2 stents were used in 110 patients (group B2). Stratification across pre-PCI diastolic distal BA tertiles (<82 degrees, 82 degrees to 106 degrees, >= 107 degrees) failed to show any difference in MACCE rates either in the entire study population (p = 0.99) or in group B patients (p = 0.78). Group B patients with post-PCI systolic-diastolic range <10 degrees had significantly higher MACCE rates (50.8% vs. 22.7%, p < 0.001); repeat revascularization and safety endpoint rates were also higher (37.4% vs. 15.5%, p = 0.002, and 25.4% vs. 14.1%, p = 0.055, respectively). Post-PCI systolic-diastolic range <10 degrees was an independent predictor of MACCE (hazard ratio: 2.65; 95% confidence interval: 1.55 to 4.52; p < 0.001) in group B patients. Conclusions A restricted post-procedural systolic-diastolic distal BA range resulted in higher 5-year adverse event rates after LMCA bifurcation PCI. Pre-PCI BA value did not affect the clinical outcome. (C) 2013 by the American College of Cardiology Foundation

Intravascular ultrasound (IVUS) has been clinically available for almost 25 years now and showed us valuable information regarding the coronary vessel lumen, its dimensions, the plaque burden and plaque characteristics that we were not able to assess by angiography alone. Using these abilities, IVUS has helped us to start, understand the atherosclerotic process in the coronary vessels. Further technical innovations partially overcame the somewhat limited image resolution of IVUS allowing more in-depth characterization and quantification of coronary plaque components. In addition, IVUS has been shown to be helpful to guide interventional procedures including optimal stent deployment in many clinical situations. In this review, we focus on the potential role of IVUS technology in interventional cardiology and on the valuable role of IVUS usage in percutaneous coronary interventions.

Aims: To assess serially the edge vascular response (EVR) of a bioresorbable vascular scaffold (BVS) compared to a metallic everolimus-eluting stent (EES). Methods and results: Non-serial evaluations of the Absorb BVS at one year have previously demonstrated proximal edge constrictive remodelling and distal edge changes in plaque composition with increase of the percent fibro-fatty (FF) tissue component. The 5 mm proximal and distal segments adjacent to the implanted devices were investigated serially with intravascular ultrasound (IVUS), post procedure, at six months and at two years, from the ABSORB Cohort B1 (n=45) and the SPIRIT II (n=113) trials. Twenty-two proximal and twenty-four distal edge segments were available for analysis in the ABSORB Cohort B1 trial. In the SPIRIT II trial, thirty-three proximal and forty-six distal edge segments were analysed. At the 5-mm proximal edge, the vessels treated with an Absorb BVS from post procedure to two years demonstrated a lumen loss (LL) of 6.68% (-17.33; 2.08) (p=0.027) with a trend toward plaque area increase of 7.55% (-4.68; 27.11) (p=0.06). At the 5-mm distal edge no major changes were evident at either time point. At the 5-mm proximal edge the vessels treated with a XIENCE V EES from post procedure to two years did not show any signs of LL, only plaque area decrease of 6.90% (-17.86; 4.23) (p=0.035). At the distal edge no major changes were evident with regard to either lumen area or vessel remodelling at the same time point. Conclusions: The IVUS-based serial evaluation of the EVR up to two years following implantation of a bioresorbable everolimus-eluting scaffold shows a statistically significant proximal edge LL; however, this fmding did not seem to have any clinical implications in the serial assessment. The upcoming imaging follow-up of the Absorb BVS at three years is anticipated to provide further information regarding the vessel wall behaviour at the edges.

Background: The prevalence and clinical sequelae of optical frequency domain imaging (OFDI)-detected intimal flaps caused by vessel trauma or plaque rupture in the proximal native coronary arteries have not been described. Methods and Results: OFDI investigation was performed following stent implantation in patients with ST-segment elevation myocardial infarction (STEMI). We defined a flap-like structure (FS) as a disruption or discontinuation of the endoluminal vessel surface, and classified as actual flap or artifact. FS in the left main stem, or maximally 20mm distal to the guiding catheter in the proximal right coronary artery were assessed. A total of 8,931 frames in 97 patients were analyzed in a frame-by-frame fashion (0.125-mm interval). OFDI identified 8 FS in 7 patients, none of which was evident angiographically. All FS were left untreated because the operators per protocol were blinded to the OFDI images. A total of 5 FS in 5 patients (5.1%) appeared to be actual flaps in which only the intima was involved (mean distance from guiding catheter: 4.8 +/- 2.7 mm). The remaining 3 FS in 3 patients were artifacts; namely, residual blood and interface light reflectivity. There were no adverse cardiac events during 6-months follow-up. Conclusions: In 5.1% of STEM patients, post-procedural OFDI identified flaps with minimal involvement of the intima in the proximal coronary arteries. A precise interpretation of FS may help decision making to avoid unnecessary procedures. (Clinical Trial Registration Information: ClinicalTrials.gov identifier: NCT01271361.)