Impact of myocardial bridging on coronary artery plaque formation and long-term mortality after heart transplantation.

OBJECTIVES: This study aimed to explore the impact of myocardial bridging (MB) on early development of cardiac allograft vasculopathy and long-term graft survival after heart transplantation. BACKGROUND: MB has been reported to be associated with acceleration of proximal plaque development and endothelial dysfunction in native coronary atherosclerosis. However, its clinical significance in heart transplantation remains unclear. METHODS: In 103 heart-transplant recipients, serial (baseline and 1-year post-transplant) volumetric intravascular ultrasound (IVUS) analyses were performed in the first 50 mm of the left anterior descending (LAD) artery. Standard IVUS indices were evaluated in 3 equally divided LAD segments (proximal, middle, and distal segments). MB was defined by IVUS as an echolucent muscular band lying on top of the artery. The primary endpoint was death or re-transplantation, assessed for up to 12.2 years (median follow-up: 4.7 years). RESULTS: IVUS identified MB in 62% of the study population. At baseline, MB patients had smaller intimal volume in the distal LAD than non-MB patients (p = 0.002). During the first year, vessel volume decreased diffusely irrespective of the presence of MB. Intimal growth diffusely distributed in non-MB patients, whereas MB patients demonstrated significantly augmented intimal formation in the proximal LAD. Kaplan-Meier analysis revealed significantly lower event-free survival in patients with versus without MB (log-rank p = 0.02). In multivariate analysis, the presence of MB was independently associated with late adverse events [hazard ratio 5.1 (1.6-22.2)]. CONCLUSION: MB appears to relate to accelerated proximal intimal growth and reduced long-term survival in heart-transplant recipients.

Heterogeneous vascular response after implantation of bare nitinol self-expanding stents in the swine femoropopliteal artery.

BACKGROUND: Mechanism of femoropopliteal in-stent restenosis has been underappreciated. AIM: The aim of this animal study was to elucidate vascular response after femoropopliteal bare nitinol self-expanding stents (SESs) implantation. METHODS: Misago, Smart Flex, or Innova stent was randomly implanted in 36 swine femoropopliteal arteries. At week 4, quantitative vessel analysis (QVA) was performed on 36 legs, of which 18 underwent histological evaluation after angiography. The remaining 18 legs underwent QVA and histological evaluation at week 13. RESULTS: Fibrin deposition was excessive at week 4. Internal elastic lamina (IEL) progressively enlarged over time, and vessel injury developed from mild level at week 4 to moderate level at week 13. Vessel inflammatory reaction was mild to moderate at week 4, and was moderate to severe at week 13. Increased fibrin deposition was an early-acting, IEL enlargement and increased vessel inflammation were long-acting, and increased vessel injury and giant cells infiltration were late-acting contributors to neointimal hyperplasia (NIH). Stent type altered time-dependent process of vessel injury, vessel inflammation, eosinophils and giant cells infiltration. Misago had less fibrin deposition and vessel enlargement, and less progressive vessel injury, vessel inflammation, and eosinophils and giant cells infiltration. Net lumen as assessed by percent diameter stenosis or minimum lumen diameter was preserved with Misago, but was not preserved with the other stents. CONCLUSIONS: In the context of bare nitinol SES platform with less progressive mechanical stress and inflammatory reaction, the advantage of less NIH outweighed the disadvantage of less vessel enlargement, leading to net lumen preservation.

Impact of Diastolic Vessel Restriction on Quality of Life in Symptomatic Myocardial Bridging Patients Treated With Surgical Unroofing: Preoperative Assessments With Intravascular Ultrasound and Coronary Computed Tomography Angiography.

[Figure: see text].

Head-to-head comparison of quantitative measurements between intravascular imaging systems: An in vitro phantom study.

INTRODUCTION: The present study aimed to compare the accuracy of quantitative measurements by contemporary intravascular imaging systems including optical frequency domain imaging (OFDI), frequency domain optical coherence tomography (FD-OCT), and 6 intravascular ultrasound (IVUS) systems. METHODS: We imaged five cylindrical phantom models made from an acrylic resin with known lumen diameters (1.51, 2.03, 3.04, 4.04, and 5.04 mm, respectively) using OFDI (FastView and LUNAWAVE, Terumo), FD-OCT (Dragonfly JP and ILUMIEN OPTIS, Abbott Vascular), and 6 mechanically rotating IVUS systems including a system, two 40-MHz, one 45-MHz, two 60-Mhz and one broad-band frequency IVUS systems. The OFDI, FD-OCT, and IVUS images were obtained using automated motorized pullback in a tank filled with 37-degree Celsius saline and, in cases of OFDI and FD-OCT, contrast-saline mixture (1:1 ratio) and contrast under the system setting of the refractive index for the corresponding flush medium. RESULTS: All the imaging systems showed good accuracy and excellent precision of lumen measurement with the relative differences between the measured diameter and actual phantom diameter being ranging from -2.9% to 8.0% and minimum standard deviations of the measured diameters (≤0.02 mm). CONCLUSION: The present study demonstrated that contemporary intravascular imaging systems including OFDI, FD-OCT, and IVUS provided clinically acceptable accuracy and excellent precision of quantitative lumen measurement in phantom models in vitro across a wide range of dimensions. Future research to confirm these findings in vivo are warranted.

Intravascular ultrasound predictors of long-term outcomes following ABSORB bioresorbable scaffold implantation: A pooled analysis of the ABSORB III and ABSORB Japan trials.

BACKGROUND: The long-term prognostic impact of IVUS findings following Absorb BVS implantation remains uncertain. This study aimed to identify the IVUS predictors of long-term clinical outcomes following ABSORB bioresorbable vascular scaffold (BVS) implantation from the pooled IVUS substudy cohorts of the ABSORB III and Japan trials. METHODS: A total of 298 lesions in 286 patients were enrolled with 2:1 randomization to ABSORB BVS vs. cobalt-chromium everolimus-eluting stents. This sub-analysis included 168 lesions of 160 patients in the Absorb arm whose post-procedural quantitative IVUS were available. The primary endpoint of this analysis was device-oriented composite endpoint (DOCE) of target lesion failure, including cardiac death, target vessel-related myocardial infarction, or ischemia-driven target lesion revascularization. The median follow-up duration was 4.9 [3.1-5.0] years. RESULTS: During follow-up, DOCE occurred in 10.1% of lesions treated with Absorb BVS. Among several post-procedural IVUS indices associated with DOCE, non-uniform device expansion (defined as uniformity index = minimum / maximum device area) (hazard ratio 0.47 per 0.1 increase [95%CI 0.28 to 0.77]; p = 0.003) and residual reference plaque burden (hazard ratio 4.01 per 10% increase [95%CI 1.50 to 10.77]; p = 0.006) were identified as independent predictors of DOCE by Cox multivariable analysis. CONCLUSIONS: Nonuniform device expansion and substantial untreated residual plaque in reference segments were associated with long-term adverse events following BVS implantation. Baseline imaging to identify the appropriate device landing zone and procedural imaging to achieve uniform device expansion if possible (e.g. through post-dilatation) may improve clinical outcomes of BVS implantation. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01751906 (ABSORB III); NCT01844284 (ABSORB Japan).

Deep learning-based intravascular ultrasound segmentation for the assessment of coronary artery disease.

BACKGROUND: Accurate segmentation of the coronary arteries with intravascular ultrasound (IVUS) is important to optimize coronary stent implantation. Recently, deep learning (DL) methods have been proposed to develop automatic IVUS segmentation. However, most of those have been limited to segmenting the lumen and vessel (i.e. lumen-intima and media-adventitia borders), not applied to segmenting stent dimension. Hence, this study aimed to develop a DL method for automatic IVUS segmentation of stent area in addition to lumen and vessel area. METHODS: This study included a total of 45,449 images from 1576 IVUS pullback runs. The datasets were randomly split into training, validation, and test datasets (0.7:0.15:0.15). After developing the DL-based system to segment IVUS images using the training and validation datasets, we evaluated the performance through the independent test dataset. RESULTS: The DL-based segmentation correlated well with the expert-analyzed segmentation with a mean intersection over union (± standard deviation) of 0.80 ± 0.20, correlation coefficient of 0.98 (95% confidence intervals: 0.98 to 0.98), 0.96 (0.95 to 0.96), and 0.96 (0.96 to 0.96) for lumen, vessel, and stent area, and the mean difference (± standard deviation) of 0.02 ± 0.57, -0.44 ± 1.56 and - 0.17 ± 0.74 mm2 for lumen, vessel and stent area, respectively. CONCLUSION: This automated DL-based IVUS segmentation of lumen, vessel and stent area showed an excellent agreement with manual segmentation by experts, supporting the feasibility of artificial intelligence-assisted IVUS assessment in patients undergoing coronary stent implantation.

Scaffold underexpansion and late lumen loss after bioresorbable scaffold implantation: Insights from ABSORB JAPAN trial.

BACKGROUND: Device underexpansion is associated with late adverse outcomes after bioresorbable vascular scaffold (BVS) implantation. This study, representing official IVUS results of the ABSORB Japan trial, aimed to characterize IVUS findings, focusing specifically on acute device expansion, and to investigate its impact on late lumen loss (LLL) with Absorb-BVS compared with cobalt-chromium everolimus-eluting stents (CoCr-EES). METHODS: ABSORB Japan enrolled 148 patients (2:1 randomization) in the IVUS cohort. Serial IVUS was prescheduled at post-procedure and 3 years. Acute device expansion was evaluated with respect to the degree and uniformity of the implanted device. RESULTS: Overall, Absorb-BVS showed smaller and more nonuniform device expansion at post-procedure, compared with CoCr-EES, which was particularly prominent in small-vessel lesions. In serial analysis, Absorb-BVS showed unique associations of smaller device expansion (r = 0.40, p = 0.001) and more nonuniformity (r = 0.29, p = 0.007) at post-procedure with greater LLL at 3 years, primarily attributable to greater negative remodeling (r = 0.39, p = 0.006). In contrast, acute device expansion showed no relation with subsequent lumen change in CoCr-EES. In Absorb-BVS, ischemic-driven target lesion or vessel revascularization (ID-TLR or ID-TVR) at 3 years occurred more frequently in small- versus large-vessel lesions (12.5% vs. 0%, p = 0.04 for ID-TLR and 15.6% vs. 2.3%, p = 0.08 for ID-TVR). Conversely, Absorb BVS had no target lesion nor vessel failure, even in small-vessel lesions, when adequate device expansion was achieved at post-procedure. CONCLUSIONS: Unlike CoCr-EES, underexpansion was associated with greater negative remodeling and LLL in Absorb-BVS. This may in part account for the poorer outcomes of Absorb-BVS than CoCr-EES when under-expanded.

Association between abdominal fat distribution and coronary plaque instability in patients with acute coronary syndrome.

BACKGROUND AND AIMS: This study aimed to assess possible association of detailed abdominal fat profiles with coronary plaque characteristics in patients with acute coronary syndrome (ACS). METHODS AND RESULTS: In 60 patients with ACS, culprit arteries were evaluated at 1-mm intervals (length analyzed: 66 ± 28 mm) by grayscale and integrated backscatter intravascular ultrasound (IB-IVUS) before percutaneous coronary intervention. Standard IVUS indexes (as a volume index: volume/length), plaque components (as percent tissue volume) and fibrous cap thickness (FCT) were assessed by IB-IVUS. Plain abdominal computed tomography was performed to evaluate subcutaneous adipose tissue (SAT) area, visceral adipose tissue (VAT) area, and VAT/SAT ratio. While SAT area only correlated with vessel volume (r = 0.27, p = 0.04), VAT area correlated positively with vessel (r = 0.30, p = 0.02) and plaque (r = 0.33, p = 0.01) volumes and negatively with FCT (r = -0.26, p = 0.049), but not with percent plaque volume and plaque tissue components. In contrast, higher VAT/SAT ratio significantly correlated with higher percent lipid (r = 0.34, p = 0.008) and lower percent fibrous (r = -0.34, p = 0.007) volumes with a trend toward larger percent plaque volume (r = 0.19, p = 0.15), as well as thinner FCT (r = -0.53, p < 0.0001). In the multiple regression analysis, higher VAT/SAT ratio was independently associated with higher percent lipid with lower percent fibrous volumes (p = 0.03 for both) and thinner fibrous cap thickness (p = 0.0001). CONCLUSION: Coronary plaque vulnerability, defined as increased lipid content with thinner fibrous cap thickness, appears to be more related to abnormal abdominal fat distribution, or so-called hidden obesity, compared with visceral or subcutaneous fat amount alone in patients with ACS.

Randomized Comparison Between Everolimus-Eluting Bioresorbable Scaffold and Metallic Stent: Multimodality Imaging Through 3 Years.

OBJECTIVES: The aim of this study was to investigate the vascular responses and fates of the scaffold after bioresorbable vascular scaffold (BVS) implantation using multimodality imaging. BACKGROUND: Serial comprehensive image assessments after BVS implantation in the context of a randomized trial have not yet been reported. METHODS: In the ABSORB Japan trial, 400 patients were randomized to a BVS (n = 266) or a cobalt-chromium everolimus-eluting stent (n = 134). Through 3 years, patients underwent serial angiography and intravascular ultrasound or optical coherence tomography (OCT). RESULTS: Luminal dimension at 3 years was consistently smaller with the BVS than with the cobalt-chromium everolimus-eluting stent (mean angiographic minimal luminal diameter 2.04 ± 0.63 mm vs. 2.40 ± 0.56 mm, mean difference -0.37 mm [95% confidence interval: -0.50 to -0.24 mm]; p < 0.001), mainly because of smaller device area (6.13 ± 2.03 mm2 vs. 7.15 ± 2.16 mm2, mean difference -1.04 mm2 [95% confidence interval: -1.66 to -0.42 mm2]; p < 0.001), and larger neointimal area (2.10 ± 0.61 mm2 vs. 1.86 ± 0.64 mm2, mean difference 0.24 mm2 [95% confidence interval: 0.06 to 0.43 mm2]; p = 0.01) by OCT. BVS-treated vessels did not show previously reported favorable vessel responses, such as positive vessel remodeling, late luminal enlargement, and restoration of vasomotion, although the OCT-based healing score was on average zero (interquartile range: 0.00 to 0.00). At 3 years, intraluminal scaffold dismantling (ISD) was observed in 14% of BVS. On serial OCT, ISD was observed in 6 lesions at 2 years, where the struts had been fully apposed at post-procedure, while ISD was observed in 12 lesions at 3 years, where 8 lesions were free from ISD on 2-year OCT. In 5 cases of very late scaffold thrombosis, strut discontinuities were detected in all 4 cases with available OCT immediately before reintervention. CONCLUSIONS: In this multimodality serial imaging study, luminal dimension at 3 years was smaller with the BVS than with the cobalt-chromium everolimus-eluting stent. ISD, suspected to be one of the mechanisms of very late BVS thrombosis, was observed in a substantial proportion of cases at 3 years, which developed between post-procedure and 2 years and even beyond 2 years. (AVJ-301 Clinical Trial: A Clinical Evaluation of AVJ-301 [Absorb™ BVS] in Japanese Population [ABSORB JAPAN]; NCT01844284).

Early invasive assessment of the coronary microcirculation predicts subsequent acute rejection after heart transplantation.

BACKGROUND: Acute allograft rejection (AAR) plays an important role in patient and graft survival; therefore, more emphasis should be placed on its prediction. This study aimed to investigate baseline clinical and diagnostic variables associated with subsequent AAR during the first year post-transplant, especially focusing on early physiologic and anatomic measures. METHODS: This study enrolled 88 heart transplant patients who underwent fractional flow reserve (FFR), coronary flow reserve (CFR), the index of microcirculatory resistance (IMR) and intravascular ultrasound (IVUS) in the left anterior descending artery at baseline (within 8 weeks post-transplant). Cardiac index (CI), pulmonary capillary wedge pressure (PCWP), mean pulmonary artery pressure (mPAP), right atrial pressure and left ventricular ejection fraction were also evaluated. AAR was defined as acute cellular rejection of grade ≥2R and/or pathological antibody-mediated rejection of grade ≥pAMR2. RESULTS: During the first year post-transplant, 25.0% of patients experienced AAR. Patients with AAR during the first year showed higher rates of recipient obesity, lower rates of recipient-donor sex mismatch and rATG and tacrolimus uses, higher PCWP, mPAP and IMR, and lower CFR at baseline, compared with those without. In the multivariate analysis, only baseline IMR ≥ 16.0 was independently associated with AAR during the first year, demonstrating high negative predictive value (96.7%). CONCLUSIONS: Invasively assessing microvascular resistance (baseline IMR ≥ 16.0) in the early post-transplant period was an independent determinant of subsequent acute allograft rejection during the first year post-transplant, suggesting that early assessment of IMR may enhance patient risk stratification and target medical therapies to improve patient outcome.

Cardiac function response to stenting in atherosclerotic renal artery disease with and without heart failure: results from the Carmel study.

AIMS: Consensus-derived guidelines recommend renal stenting for patients with atherosclerotic renal artery disease (ARAD) and heart failure (HF). The aim of this prospective multi-centre observational study was to verify our hypothesis that changes in E/e', an echocardiographic correlate of left ventricular (LV) filling pressure, following renal stenting may differ between ARAD patients with and without HF. METHODS AND RESULTS: This study enrolled de novo ARAD patients undergoing renal stenting at 14 institutions. The primary endpoint was the difference in E/e' change between ARAD patients with and without HF. Clinical and echocardiographic data were prospectively collected at baseline, the day following renal stenting, and 1 month and 6 months afterwards. ARAD patients with HF were defined as patients with New York Heart Association (NYHA) Class 2 and more, or a history of HF hospitalization. A total of 76 patients were included, and 39% were ARAD patients with HF. ARAD patients with HF had significantly lower estimated glomerular filtration rate (P = 0.028) and higher NYHA functional class (P < 0.001) and Minnesota Living with Heart Failure Questionnaire (MLHFQ) score (P = 0.001) than ARAD patients without HF. Also, ARAD patients with HF had significantly lower LV ejection fraction (P = 0.003) and e'-velocity (P = 0.003) and higher E/e' ratio (P = 0.001), left atrial volume index (LAVI) (P = 0.046), LV end-diastolic volume (LVEDV) (P = 0.001), LV end-systolic volume (LVESV) (P = 0.001), and LV mass index (P = 0.009) than ARAD patients without HF. All procedures were successful. In contrast to blood pressure and renal function, there was a significant interaction in E/e' (Pinteraction  < 0.001) between time and HF, and ARAD patients with HF showed a significant (P < 0.001) decrease in E/e' albeit those without HF. By the same token, there was a significant interaction in NYHA class (Pinteraction  < 0.001), MLHFQ score (Pinteraction  = 0.018), E-velocity (Pinteraction  = 0.002), LAVI (Pinteraction  = 0.001), LVEDV (Pinteraction  = 0.003), and LVESV (Pinteraction  = 0.001) between time and HF with a significant improvement in all these variables in ARAD patients with HF (NYHA class, P = 0.001; MLHFQ score, P = 0.002; E-velocity, P = 0.005; LAVI, P = 0.001; LVEDV, P = 0.017; and LVESV, P = 0.011). CONCLUSIONS: Change in LV filling pressure after renal stenting differed between ARAD patients with and without HF, with a significant improvement in LV filling pressure in patients with HF-ARAD. These unique findings might support clinical cardiac benefits of renal stenting in ARAD patients with HF.

Comparison between instantaneous wave-free ratio versus morphometric assessments by intracoronary imaging.

Anatomical measurements obtained by intracoronary imaging devices are reported to correlate significantly with fractional flow reserve (FFR). Instantaneous wave-free ratio (iFR) is a nonhyperemic index of stenosis severity with discordant reports regarding its accuracy in relation to FFR. There is no information on the correlation of iFR with measurements derived from intracoronary imaging devices. The purpose of this study was to assess the relationship among iFR, intravascular ultrasound (IVUS), and optical frequency domain imaging (OFDI) parameters. Eighty lesions in 72 patients who underwent elective angiography and had intermediate lesions were enrolled. All lesions were assessed by iFR, FFR, IVUS, and OFDI. iFR was ≤ 0.89 in 21 (26%) lesions and FFR was ≤ 0.80 in 41 (51%) lesions. iFR correlated significantly with both IVUS-derived minimum lumen area (MLA) (r = 0.375, p = 0.003) and OFDI-derived MLA (r = 0.357, p = 0.005). FFR also correlated significantly with both IVUS-derived MLA (r = 0.472, p < 0.001) and OFDI-derived MLA (r = 0.445, p < 0.001). Among the lesions with FFR ≤ 0.80, iFR > 0.89 (mismatch) was observed in 20 lesions. There was no lesion with iFR ≤ 0.89 (reverse mismatch) among the lesions with FFR > 0.80. The lesion location among three major coronary vessels was related with the discrepancy between iFR and FFR (p = 0.007). In conclusion, iFR and FFR showed a significant correlation with IVUS and OFDI measurements. The discrepancy of iFR and FFR was associated with the lesion locations.

Bioresorbable Scaffold for Treatment of Coronary Artery Lesions: Intravascular Ultrasound Results From the ABSORB Japan Trial.

OBJECTIVES: The aim of this study was to characterize post-procedural intravascular ultrasound (IVUS) findings in the ABSORB Japan trial, specifically stratified by the size of target coronary arteries. BACKGROUND: Despite overall noninferiority confirmed in recent randomized trials comparing bioresorbable vascular scaffolds (BVS) (Absorb BVS) and cobalt-chromium everolimus-eluting metallic stents (CoCr-EES), higher event rates of Absorb BVS have been reported with suboptimal deployment, especially in small coronary arteries. METHODS: In the ABSORB Japan trial, 150 patients (2:1 randomization) were scheduled in the IVUS cohort. Small vessel was defined as mean reference lumen diameter <2.75 mm. Tapered-vessel lesions were defined as tapering index (proximal/distal reference lumen diameter) ≥1.2. RESULTS: Overall, IVUS revealed that the Absorb BVS arm had smaller device expansion than the CoCr-EES arm did, which was particularly prominent in small- and tapered-vessel lesions. Higher tapering index was also associated with higher rates of incomplete strut apposition in Absorb BVS, but not in CoCr-EES. With respect to procedural techniques, small-vessel lesions were treated more frequently with noncompliant balloons at post-dilatation but using significantly lower pressure in the Absorb BVS arm. In contrast, tapered-vessel lesions were post-dilated at equivalent pressure but with significantly smaller balloon catheters in the Absorb BVS arm, compared with the CoCr-EES arm. CONCLUSIONS: The significantly smaller device expansion especially in small vessels may account for the poorer outcomes of Absorb BVS in this lesion type. Appropriate optimization strategy, possibly different between polymeric and metallic devices, needs to be established for bioresorbable scaffold technology. (AVJ-301 Clinical Trial: A Clinical Evaluation of AVJ-301 Absorb™ BVS) in Japanese Population [ABSORB JAPAN]; NCT01844284).

Assessment of bioresorbable scaffold with a novel high-definition 60 MHz IVUS imaging system: Comparison with 40-MHz IVUS referenced to optical coherence tomography.

BACKGROUND: In vivo assessment of bioresorbable scaffold (BRS) is of growing clinical interest. The novel 60MHz high-definition intravascular ultrasound (HD-IVUS) has been developed to overcome the limitations of conventional 40 MHz IVUS. This study aimed to evaluate the performance and limitations of 60 MHz HD-IVUS compared with 40 MHz IVUS with respect to polymeric-strut visualization, quantitative and qualitative analysis, and feasibility of high-speed pullback in the assessment of BRS. METHODS AND RESULTS: In a bench-test model, 361 struts were analyzed to evaluate the influence of ultrasound-beam angles and proximity of adjacent struts on IVUS visualization of BRS struts. Various settings were created by deforming the BRS and positioning the transducer offcenter. In an in vivo swine coronary model, scaffold and lumen areas, degree of visible external elastic membrane, incomplete strut apposition, and strut fracture were evaluated in 59 matched cross-sections obtained at conventional (0.5 mm/sec) and high speed (10 mm/sec) pullbacks. Both studies utilized optical coherence tomography (OCT) as reference. Overall, 60 MHz HD-IVUS demonstrated significantly improved visualization of polymeric struts compared with 40 MHz IVUS (well-visualized: 84.5% vs 62.3%, not visible: 4.4% vs 13.9%, respectively. P < 0.001), which was less affected by the beam angle and adjacent strut proximity. In the in vivo model, 60-MHz HD-IVUS showed better agreement of area measurements and strut abnormalities with OCT than 40 MHz IVUS. These findings were also confirmed on high-speed pullback images of 60 MHz HD-IVUS. CONCLUSION: As referenced to OCT, this study showed superiority of 60 MHz HD-IVUS over 40 MHz IVUS in the assessment of BRS with feasibility of high-speed pullback imaging.

Impact of Stent Size Selection on Acute and Long-Term Outcomes After Drug-Eluting Stent Implantation in De Novo Coronary Lesions.

BACKGROUND: Although significant undersizing often results in incomplete stent apposition or underexpansion, the possible impact of oversized stent implantation on arterial wall injury has not been systematically investigated with drug-eluting stents. The aim of this study was to investigate the impact of stent oversizing on acute and long-term outcomes after drug-eluting stents implantation in de novo coronary lesions. METHODS AND RESULTS: Serial (baseline and 6-12 months) coronary angiography and intravascular ultrasound were performed in 2931 lesions treated with drug-eluting stents (355 sirolimus, 846 paclitaxel, 1387 zotarolimus, and 343 everolimus). The percentage of stent oversizing to angiographic reference vessel diameter (RVD) was calculated as (nominal stent diameter-RVD)/RVD×100 (%). Clinical outcomes, including target lesion revascularization and stent thrombosis, were followed for 1 year. Overall, smaller preintervention RVD was associated with higher percentage of stent oversizing (P<0.001). The significant oversizing group underwent less post-dilatation (P=0.002) but achieved greater stent expansion (P<0.001) and less incomplete stent apposition (P<0.001) without increase of edge dissection after procedure. When stratified by vessel size and stent oversizing, progressive decreases of restenosis (P=0.002) and target lesion revascularization rates (P=0.007) were found in favor of larger vessel size and oversized stents. Stent thrombosis was observed the most in small RVD with low percentage of stent oversizing group among the subgroups (P=0.040). CONCLUSIONS: The positive impact of stent oversizing was documented on procedural and clinical outcomes. In particular, small vessels treated with smaller stents were associated with greater adverse events, suggesting that aggressive selection of larger stents, with appropriate attention to edge effects, may optimize long-term outcomes, even in drug-eluting stents implantation.

The effect of negative remodeling on fractional flow reserve after cardiac transplantation.

BACKGROUND: Negative remodeling is a common occurrence early after cardiac transplantation. Its impact on the development of myocardial ischemia is not well documented. The aim of this study is to investigate the impact of negative remodeling on fractional flow reserve after cardiac transplantation. METHODS: Thirty-four cardiac transplant recipients underwent intravascular ultrasound (IVUS) and fractional flow reserve (FFR) assessment soon after transplantation and one year later. Patients were divided into those with and without negative remodeling based on IVUS, and the impact on FFR was assessed. In the 19 patients with negative remodeling, there was no significant change in plaque volume (119.3±82.0 to 131.3±91.2mm3, p=0.21), but vessel volume (775.6±212.0 to 621.9±144.1mm3, p<0.0001) and lumen volume (656.3±169.1 to 490.7±132.0mm3, p<0.0001) decreased significantly and FFR likewise decreased significantly (0.88±0.06 to 0.84±0.07, p=0.04). In the 15 patients without negative remodeling, vessel volume did not change (711.7±217.6 to 745.7±198.5, p=0.28), but there was a significant increase in plaque volume (126.8±88.3 to 194.4±92.7, p<0.001) and a resultant significant decrease in FFR (0.89±0.05 to 0.85±0.05, p=0.01). CONCLUSION: Negative remodeling itself, without any change in plaque volume can cause a significant decrease in fractional flow reserve after cardiac transplantation and appears to be another possible mechanism for myocardial ischemia.

Impact of attenuated-signal plaque observed by intravascular ultrasound on vessel response after drug-eluting stent implantation.

BACKGROUND AND AIMS: The aim of this study was to investigate the impact of attenuated-signal plaque (ASP) observed by intravascular ultrasound (IVUS) on vessel response after drug-eluting stent implantation. METHODS: Data were derived from the IVUS cohort of the J-DESsERT trial comparing paclitaxel- and sirolimus-eluting stents. Serial IVUS analysis (pre- and post-intervention, and 8-month follow-up) was performed in 136 non-AMI lesions. ASP was defined as hypoechoic plaque with ultrasound attenuation without calcification. Calcified plaque (CP) was defined as brightly echoreflective plaque with acoustic shadowing. ASP and CP scores were calculated by grading their measured angle as 0 to 4 for 0°, <90°, 90-180°, 180-270° and >270°, respectively. The entire stented segment was analyzed at 1-mm intervals. RESULTS: At pre-intervention, ASP was observed in 40.4% of lesions, and this group had greater % neointimal volume (%NIV) at follow-up than the no-ASP group (p = 0.011). ASP score at pre-intervention positively correlated with %NIV (p = 0.023). During the follow-up, ASP score significantly decreased (p < 0.001), and CP score significantly increased (p < 0.001), with a negative correlation between them (p < 0.001). A decrease in the ASP score was associated with less %NIV in PES (p = 0.031), but not in SES (p = 0.229). CONCLUSIONS: The greater extent of plaque with IVUS-signal attenuation at pre-intervention and its persistence during follow-up were associated with neointimal proliferation, possibly representing sustained inflammatory status, depending on the type of DES used.

Impact of stent diameter on vascular response after self-expanding paclitaxel-eluting stent implantation in the superficial femoral artery.

BACKGROUND: The optimal sizing of self-expanding paclitaxel-eluting stents (PES) in the treatment for superficial femoral artery (SFA) lesions is unclear. This study sought to investigate the influence of PES diameter on stent patency in SFA lesions using optical frequency domain imaging (OFDI). METHODS: A total of 20 de novo SFA lesions were randomized 1:1 to receive either self-expanding PES with a nominal diameter of 6mm or 8mm. Follow-up angiography and OFDI was scheduled six months after stent implantation, and volumetric OFDI analysis was performed to evaluate vascular response to the stents. Volume index (VI) was defined as the volume divided by the stent length. The primary end point was lumen VI at the 6-month follow-up. Secondary end point was minimum lumen diameter (MLD) by quantitative vascular angiography (QVA) at the follow-up. RESULTS: Stent length was 78.0±23.9mm in the 6-mm group and 70.0±23.6mm in the 8-mm group (p=0.46). Baseline QVA data were also similar between the two groups. MLD immediately after stent implantation was similar between the two groups (4.2±0.5mm in the 6-mm group and 3.9±0.5mm in the 8-mm group, p=NS). At the 6-month follow-up, MLD was greater in the 8-mm group compared to the 6-mm group (4.0±1.0mm vs. 3.2±0.4mm, p<0.05). Stent VI was larger in the 8-mm group (28.4±6.7mm3/mm vs. 22.2±1.2mm3/mm, p=0.01). Neointimal VI was similar between the two groups (5.8±2.9mm3/mm vs. 5.2±2.6mm3/mm, p=0.68). Lumen VI was greater in the 8-mm group (23.2±7.6mm3/mm vs. 17.3±2.6mm3/mm, p=0.04). CONCLUSIONS: Chronic stent enlargement resulted in greater lumen area after implantation of self-expanding PES with a large diameter at the mid-term follow-up. Stent diameter might be important for stent patency in procedure with PES for SFA lesions.

Impact of analysis interval size on the quality of optical frequency domain imaging assessments of stent implantation for lesions of the superficial femoral artery.

OBJECTIVES: This study aimed to investigate the influence of analysis interval size on optical frequency domain imaging (OFDI) assessment of stent therapy for lesions of the superficial femoral artery (SFA). BACKGROUND: No consensus or validating data are available with respect to the methodology of intravascular imaging analysis for the peripheral arteries. METHODS: OFDI was performed for 30 SFA lesions, during endovascular therapy and at the 6-month follow-up. Initially, lumen and stent borders were traced at 1-mm axial intervals. Volumes were calculated using a PC-based software, and the volume index (VI) was defined as the volume divided by the stent length. Two additional OFDI analyses were performed using 2-mm and 5-mm intervals, thereby reducing the number of cross-sectional image frames analyzed. RESULTS: The mean stent length was 89.7 ± 35.2 mm. The mean difference in baseline minimum lumen area (MLA) was 0.4 mm2 between MLA values from the 1-mm and 2-mm interval analyses, and 2.2 mm2 between MLA values from the 1-mm and 5-mm interval analyses. In volumetric analysis, there were excellent correlations and good agreements for stent, lumen, and neointimal VI measurements obtained on the basis of different analysis intervals. CONCLUSIONS: Using large intervals in OFDI analyses of SFA lesions resulted in few differences in measurement variability of volumetric parameters. However, planar analysis for MLA assessment can be susceptible to high variability when large intervals are applied. © 2016 Wiley Periodicals, Inc.

Comparing the vascular response in implantation of self-expanding, bare metal nitinol stents or paclitaxel-eluting nitinol stents in superficial femoral artery lesions: a serial optical frequency domain imaging study.

AIMS: This study sought to investigate differences in vascular response between self-expanding bare metal nitinol stents (BMS) and paclitaxel-eluting nitinol stents (PES), in superficial femoral artery (SFA) disease, using optical frequency domain imaging (OFDI). METHODS AND RESULTS: Six months after stent implantation, follow-up quantitative vascular angiography (QVA) and OFDI assessment were scheduled to evaluate vascular response. Volume index (VI) was defined as volume divided by stent length. The primary endpoint was OFDI-derived late lumen area loss, defined as lumen VI post stent implantation minus lumen VI at follow-up. A total of 28 SFA lesions were analysed, with cases randomised to receive either BMS or PES implantation. QVA-derived diameter stenosis at six-month follow-up was lower in the PES group than in the BMS group (28.5% vs. 39.7%, p=0.04). After six months, BMS VI increased by 33.8% (20.7±3.7 to 27.7±3.5 mm3/mm), whilst PES exhibited an increase of 32.1% (19.0±2.3 to 25.1±4.7 mm3/mm). Neointimal VI was smaller (7.4±2.6 mm3/mm vs. 10.5±3.2 mm3/mm, p<0.01) and late lumen area loss was lower (2.9±1.3 mm3/mm vs. 5.6±2.8 mm3/mm, p<0.01) in the PES group. CONCLUSIONS: Serial volumetric OFDI analyses confirmed significantly smaller amounts of neointimal tissue and lower late lumen area loss following PES implantation for SFA lesions at short-term follow-up.