Stent Volume Research Articles

Evaluation and clinical significance of contrast-enhanced ultrasound on changes in liver blood flow perfusion after TIPS surgery.

To investigate the clinical value of contrast-enhanced ultrasound in the prediction of hepatic encephalopathy (HE) in patients with hepatitis B cirrhosis after intrahepatic portal-systemic shunt via jugular vein. In this retrospective study, we collected data from 75 patients with hepatitis B, cirrhosis, and portal hypertension who underwent jugular intrahepatic portosystemic shunt from February 2019 to February 2022. The diagnostic instrument used was the TOSHIBA Aplio500 color Doppler ultrasound with contrast-enhanced ultrasound capabilities. The trial group comprised 20 patients with HE within 3 months postsurgery, while the control group (CG) included 55 patients without HE within the same postoperative period. All patients underwent various examinations before and within 48 hours after surgery, including observation of liver and spleen size and stent position, as well as assessment of blood flow direction in portal and hepatic veins. Subsequently, contrast-enhanced ultrasound was employed to examine and observe perfusion changes of contrast agents in hepatic veins, hepatic arteries, and portal veins (PV). Changes in PV pressure gradient, intrahepatic, and stent blood flow perfusion (BFP) were explored in both postoperative trials and CGs. The trial group exhibited higher BFP volume, PV pressure gradient difference, and percentage decrease compared to the CG. A weak positive correlation was observed between blood flow within the liver stent and PV pressure gradient difference, as well as the percentage decrease in PV pressure gradient. The correlation coefficient between blood flowing perfusion volume within the stent and the difference in PV pressure gradient was R = 0.415 (P = .000). The correlating coefficient between BFP amount within the stent and the percentage decrease in PV pressure gradient was R = 0.261 (P = .027). The area under the receiver operating characteristic curve for stent perfusion volume, difference in PV pressure gradient, and percentage decrease in PV pressure gradient was 0.691, 0.759, and 0.742, respectively. An increase in PV pressure gradient accelerates blood flow within the stent, predisposing to HE. Changes in hepatic BFP following transjugular intrahepatic portosystemic shunt can effectively predict the occurrence of HE, demonstrating significant clinical relevance.

Comparison of intravascular lithotripsy and rotational atherectomy for the treatment of heavily calcified coronary lesions: the STIFF ( S tenoses with calcificaTIon treated with angioplasty e FF ected with dedicated interventional tools) study.

Percutaneous coronary interventions in heavily calcified coronary lesions are associated with technical difficulties and the worse prognosis. Lesion preparation is important to reduce complications and improve outcomes. The aim of this study is to compare the results of rotational atherectomy (RA) and intravascular lithotripsy (IVL) at achieving optimal stent implantation using intravascular ultrasound criteria. Retrospective, single-center study comparing patients with heavily calcified coronary lesions that underwent percutaneous coronary interventions using RA or IVL. 25 patients (13 in the RA group and 12 in the IVL group) were included. Reference vessel diameter was similar between the groups [2.59 (2.51-3.63) mm in the RA group vs. 2.79 (2.59-3.16) mm in the IVL group; P = 0.89], as were minimal lumen area [1.02 (0.80-1.23) mm vs. 1.40 (1.01-1.40) mm; P = 0.43] and diameter stenosis [60.4% (52.3-72.3) vs. 56.1% (47.8-61.3); P = 0.56). The final minimal lumen area was significantly larger in the IVL group [7.6 mm 2 (5.8-8.6) vs. 5.4 mm 2 (4.5-6.2); P = 0.01] as were lumen area gain [4.1 mm 2 (2.6-5.9) vs. 2.3 mm 2 (1.4-3.6); P = 0.01] and final stent volume [491.2 mm 3 (372.2-729.8) vs. 326.2 mm 3 (257.1-435.4); P = 0.03]. In the RA group, 69.2% of the patients achieved the preestablished intravascular ultrasound-based criteria for successful stent implantation, vs. 100% of the patients in the IVL group ( P = 0.04). Patients in the IVL group achieved the Intravascular Ultrasound Versus Angiography-Guided Drug-Eluting Stent Implantation trial criteria of successful stent implantation more frequently than those treated with RA.

A phenomenological model of pulsatile blood pressure-affected degradation of polylactic acid (PLA) vascular stent.

The stent implantation may alter the post-operative patient's blood pressure, and bioresorbable vascular stents (BVS) as a candidate to treat vascular diseases, its degradation is affected by mechanical stress, thus, the altered pressure representing varying stress level will result in different degradation behaviors of the BVS. This paper first proposed a novel stress-regulated PLA degradation model that included swelling factor, and then the degradation evolutions of a PLA BVS within 180days under normal and high blood pressures were simulated by finite element method, and more four degradation indexes were defined to study the effects of the two blood pressures on the degradation of the PLA BVS. The results showed that the high pressure weakly accelerated the degradation of the PLA BVS with respect to the normal pressure by examining the four indexes, e.g., the residual stent volume decreased to 0.72 and 0.69, respectively for the normal and high pressures at day 180. The current finding provided a theoretical understanding of the PLA BVS degradation, and hinted that the PLA BVS may not need to be elaborately selected in clinical practices for treating hypertensive patients.

Optimized structure design of asymmetrical Mg alloy cerebrovascular stent with high flexibility

In the treatment of cerebral artery stenosis via stent intervention, it is required that the stent can pass through the tortuous blood vessel with high curvature to reach the lesion position smoothly, and the damage to the artery should be as small as possible. This determines that the coronary artery stent cannot be directly applied to the diseased cerebrovascular, but a specialized cerebrovascular stent with high flexibility should be specifically designed. Differing from the commonly employed symmetrical structure, in this work, an asymmetrical and unequal-heigh stent structure was designed, which helps to improve the flexibility of the stent and reduces the self-contact phenomenon that occurs after the ordinary stent is bent. To balance the comprehensive properties of the stent, multi-objective optimization on the stent structure was carried out. The optimized stent structure shows better radial strength and flexibility and does not significantly affect equivalent plastic strain after stent expansion and volume average stress. In addition, this work provides a universal workflow for the customized stent structure.

Impact of coronary bifurcation angle on stent malapposition in a randomized comparison between proximal optimization technique followed by side branch dilatation and kissing balloon inflation.

The impact of coronary bifurcation angle (BA) on incomplete stent apposition (ISA) after crossover stenting followed by side branch (SB) intervention has not been established. A total of 100 crossover stentings randomly treated with proximal optimization technique followed by short balloon dilation in the SB (POT-SBD group, 48 patients) and final kissing balloon technique (KBT group, 52 patients) were analyzed in the PROPOT trial. Major ISA with maximum distance>400μm and its location was determined using optical coherence tomography before SB intervention and at the final procedure. The BA was defined as the angle between the distal main vessel and SB. Optimal POT was determined when the difference in stent volume index between the proximal and distal bifurcation was greater than the median value (0.86mm3/mm) before SB intervention. Major ISA was more frequently observed in the POT-SBD than in the KBT group (35% versus 17%, p<0.05). In the POT-SBD group, worsening ISA after SBD was prominent at the distal bifurcation. The BA was an independent predictor of major ISA (odds ratio 1.04, 95% confidence interval 1.00-1.07, p<0.05) with a cut-off value of 59.5° (p<0.05). However, the cases treated with optimal POT in the short BA (<60°) indicated the lowest incidence of major ISA. In the KBT group, BA had no significant impact. A wide BA has a potential risk for the occurrence of major ISA after POT followed by SBD in coronary bifurcation stenting.

Straightened Segmentation in 4D Cardiac CT: A Practical Method for Multiparametric Characterization of the Landing Zone for Transcatheter Pulmonary Valve Replacement

Cardiac computed tomography angiography (C-CTA) is crucial in assessing the right ventricular outflow tract (RVOT) prior to a transcatheter pulmonary valve replacement (TPVR), as an incorrect evaluation can make the procedure more challenging and can lead to device-related complications. This study aimed to evaluate the feasibility and accuracy of 4D straightened segmentation for a landing zone analysis over anatomical segmentation. Seven pre-operative CTAs and seven post-operative CTAs were used to measure the cross-sectional area, circumference, and diameters at five selected planes as the landing zone for TPVR and compared these to the 4D straightened model with the anatomical model. Furthermore, the right ventricular volume, stent volume, and 4D ellipticity index were calculated from the 4D straightened model. The 4D straightened segmentation had comparable accuracy and efficacy for the measurements at the landing zone. The cross-sectional area and the circumference varied greatly at the RVOT and the basal plane of the pulmonary valve compared with the other three planes of the 4D straightened models from the pre-operative CTAs; however, only the values at the RVOT were found to vary greatly from the post-operative CTAs. The 4D straightened model can provide accurate measurements and is thus a useful method for the periprocedural evaluation of TPVR.

Long-term changes after carotid stenting assessed by intravascular ultrasound and near-infrared spectroscopy.

Long-term effect of carotid stenting (CAS) on the stabilization of the plaque is almost unrecognized. Vascular healing and remodeling might seal the atherosclerotic plaque with neointimal hyperplasia decreasing the vulnerability. We aimed to assess long-term change in the lipid signal, stent and luminal dimensions and restenosis after CAS with the intravascular ultrasound (IVUS) and near-infrared spectroscopy (NIRS) imaging. We performed follow-up angiography and NIRS-IVUS imaging of 58 carotid stents in 52 patients. Median time from CAS to the follow-up examination was 31 months (range, 5-56). The lipid signal of the stented segment was calculated from a NIRS-derived chemogram (a spectroscopic map) as the lipid core burden index (LCBI, a dimensionless number from 0 to 1,000). Planimetric and volumetric measurements from IVUS were performed to assess change in minimal stent area (MSA), minimal luminal area (MLA), stent and luminal volume, late stent expansion and percentage in-stent restenosis (ISR) volume. During the follow-up period, the mean (±SD) LCBI significantly decreased from 32±56 to 17±27 (P=0.002). The mean stent volume significantly increased from 717±302 to 1,019±429 mm3 (P<0.001) with mean stent expansion 43%±24%. The mean luminal volume increased from 717±302 to 760±359 mm3 (P=0.025) due to ISR encroaching 26%±15% of the stent volume. Lipid signal decreased during the follow-up period suggesting stabilization of the plaque. Late stent expansion was balanced with neointimal hyperplasia. The trial is registered under clinicaltrials.gov NCT03141580.

The determinants and significance of intraluminal stent protrusion in patients with acute myocardial infarction

Abstract Background The mchanisms leading to intraluminal stent protrusion in patients following primary coronary angioplasty for ST-elevation myocardial infarction (STEMI) are not fully elucidated. Purpose We sought to investigate composition of stent protrusion, its systemic and local determinants as well as its consequences for epicardial blood flow restoration in STEMI patients. Methods We enrolled 85 STEMI patients with median age 61 (interquartile range 54–69) years. In all patients optical coherence tomography of an infarct-related artery was performed first following epicardial blood flow restoration after aspiration thrombectomy and second after final stent deployment. On admission, besides standard laboratory investigations we measured calibrated automated thrombogram parameters including time to start clotting, time to peak thrombin generation, peak thrombin generation and endogenous thrombin potential as well as ex vivo measured fibrin clot permeability reflecting fibrin pore size and fibrin clot lysis time. Results A median volume of stent protrusion was 13.4 (8.5–25.4) mm3 while atherothrombotic burden defined as a ratio of free intraluminal thrombus and tissue protrusion divided by stent volume was 6 (3.9–7.5)%. The main component of stent protrusion was lipid tissue in 32 (37.6%), fibrous tissue in 27 (31.8%) and thrombus in 26 (30.6%) patients. A volume of stent protrusion was correlated with total stent volume (R=0.79, P&amp;lt;0.001) and the length of lipid reach pool in the naïve coronary vessel intima (R=0.31, P=0.007) whereas atherothrombotic burden was correlated with residual thrombus volume before stent implantation (R=0.34, P=0.003), arcus of maximal lipid reach pool in the naïve coronary vessel intima (R=0.25, P=0.03) and stent area (R=0.26, P=0.02). The residual thrombus volume after aspiration thrombectomy was correlated with clot permeability (R=0.024, P=0.04) and inversely correlated with time to peak thrombin generation (R=−0.23, P=0.04). A temporary deterioration of epicardial blood flow of at least 1 point in Thrombolysis in Myocardial Infarction scale following stent implantation detected in 20 (23.5%) patients was associated with shorter lag time (3.0 [2.7–3.3] vs. 3.3 [3.0–4.0] min, P=0.015), shorter time to peak thrombin generation (5.7 [5.3–6.1] vs. 6.3 [5.7–7.1] min, P=0.026) and more frequent presence of lipid-rich stent protrusion (65 vs. 29%, P=0.007) as compared to the patients without slow-flow phenomenon after stent deployment. Conclusions The total volume of stent protrusion is correlated with local determinants including stent size and lipid content in the naïve coronary artery intima. After adjustment for stent volume, atherothrombotic burden is additionaly affected by residual thrombus volume after aspiration thrombectomy. However, patients with faster thrombin formation and lipid-rich stent protrusion are more prone to slow-flow phenomenon following stent implantation. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Science Center of Poland

A New Method to Optimize Stent Deployment by High-Definition Intravascular Ultrasound.

Optimal stent deployment by intravascular ultrasound (IVUS) improves outcome, but it can only be achieved in 50% of patients. We investigated the feasibility and effect of a new method of stent optimization on optimal stent deployment. IVUS analyses of 168 coronary segments were performed after angiography-guided stenting (AGS) and stent optimization in 29 patients (30 lesions). Minimum stent area (MSA), stent volume index (SVI), lumen area, external elastic membrane (EEM), and plaque burden (PB) were measured. Stent optimization included post-stent dilation with a balloon sized by high-definition (HD)-IVUS to the distal reference EEM diameter for stent underexpansion or malapposition, and stenting of PB >50% or edge dissection. After AGS, stent deployment was suboptimal in 77% of patients. After stent optimization, MSA and SVI were significantly larger than AGS. Adequate stent expansion - defined as MSA ≥5.4 mm² or ≥90% of distal reference lumen area - was significantly higher after stent optimization vs AGS (87% vs 56%, respectively; P=.02). Optimal stent deployment - a composite of adequate stent expansion, no malapposition, PB <50% at the stent edges, and no edge dissection - was markedly higher after stent optimization vs AGS (87% vs 35%, respectively; P<.01). After stent deployment and postdilation, stent results were suboptimal in two-thirds of patients. This simple online stent optimization by HD-IVUS was feasible and resulted in optimal stent deployment in the majority of patients. Randomized studies are warranted to compare the rate of optimal stent deployment and outcomes of this strategy vs other techniques.

Three dimensional reconstruction of coronary artery stents from optical coherence tomography: experimental validation and clinical feasibility

The structural morphology of coronary stents (e.g. stent expansion, lumen scaffolding, strut apposition, tissue protrusion, side branch jailing, strut fracture), and the local hemodynamic environment after stent deployment are key determinants of procedural success and subsequent clinical outcomes. High-resolution intracoronary imaging has the potential to enable the geometrically accurate three-dimensional (3D) reconstruction of coronary stents. The aim of this work was to present a novel algorithm for 3D stent reconstruction of coronary artery stents based on optical coherence tomography (OCT) and angiography, and test experimentally its accuracy, reproducibility, clinical feasibility, and ability to perform computational fluid dynamics (CFD) studies. Our method has the following steps: 3D lumen reconstruction based on OCT and angiography, stent strut segmentation in OCT images, packaging, rotation and straightening of the segmented struts, planar unrolling of the segmented struts, planar stent wireframe reconstruction, rolling back of the planar stent wireframe to the 3D reconstructed lumen, and final stent volume reconstruction. We tested the accuracy and reproducibility of our method in stented patient-specific silicone models using micro-computed tomography (μCT) and stereoscopy as references. The clinical feasibility and CFD studies were performed in clinically stented coronary bifurcations. The experimental and clinical studies showed that our algorithm (1) can reproduce the complex spatial stent configuration with high precision and reproducibility, (2) is feasible in 3D reconstructing stents deployed in bifurcations, and (3) enables CFD studies to assess the local hemodynamic environment within the stent. Notably, the high accuracy of our algorithm was consistent across different stent designs and diameters. Our method coupled with patient-specific CFD studies can lay the ground for optimization of stenting procedures, patient-specific computational stenting simulations, and research and development of new stent scaffolds and stenting techniques.

Prediction of Coronary Stent Underexpansion by Pre-Procedural IntravascularUltrasound-Based DeepLearning.

The aim of this study was to develop pre-procedural intravascular ultrasound (IVUS)-based models for predicting the occurrence of stent underexpansion. Although post-stenting IVUS has been used to optimize percutaneous coronary intervention, there are no pre-procedural guidelines to estimate the degree of stent expansion and provide preemptive management before stent deployment. A total of 618 coronary lesions in 618 patients undergoing percutaneous coronary intervention were randomized into training and test sets in a 5:1 ratio. Following the coregistration of pre- and post-stenting IVUS images, the pre-procedural images and clinical information (stent diameter, length, and inflation pressure; balloon diameter; and maximal balloon pressure) were used to develop a regression model using a convolutional neural network to predict post-stenting stent area. To separate the frames with from those without the occurrence of underexpansion (stent area<5.5mm2), binary classification models (XGBoost) were developed. Overall, the frequency of stent underexpansion was 15% (5,209 of 34,736 frames). At the frame level, stent areas predicted by the pre-procedural IVUS-based regression model significantly correlated with those measured on post-stenting IVUS (r=0.802). To predict stent underexpansion, maximal accuracy of 94% (area under the curve=0.94) was achieved when the convolutional neural network- and mask image-derived features were used for the classification model. At the lesion level, there were significant correlations between predicted and measured minimal stent area (r=0.832) and between predicted and measured total stent volume (r=0.958). Deep-learning algorithms accurately predicted incomplete stent expansion. A data-driven approach may assist clinicians in making treatment decisions to avoid stent underexpansion as a preventable cause of stent failure.

Effect of neointimal tissue morphology on vascular response to balloon angioplasty in lesions with in-stent restenosis after drug-eluting stent deployment: an optical coherence tomography analysis.

This study aimed to evaluate the vascular response to balloon angioplasty for drug-eluting stent (DES) in-stent restenosis (ISR) lesions based on our novel optical coherence tomography (OCT) classification to establish the optimal treatment strategy for ISR lesions after DES implantation. A total of 104 ISR lesions after DES implantation were imaged by OCT and categorized into the following six patterns: type I-homogeneous high-intensity tissue, type II-heterogeneous tissue with signal attenuation, type III-speckled heterogeneous tissue, type IV-mixed tissue containing poorly delineated region with invisible strut, type V-mixed tissue containing sharply delineated low-intensity region, and type VI-bright protruding tissue with an irregular surface. Serial volumetric OCT analysis was performed before and after balloon dilation to evaluate the vascular response to balloon angioplasty. After balloon dilation, the minimal decrease in neointimal volume was noted in type I lesions and maximal in type III lesions. In contrast, the increase in stent volume was significantly more in type I lesions than others. Neointimal tissue characterization by OCT allows us to provide useful information about the vascular response to balloon dilation, which can influence the therapeutic strategy for DES ISR lesions.

A new intravascular ultrasound-guided stenting strategy compared with angiography on stent expansion and procedural outcomes in patients with positive lesion remodeling.

We investigated the role of a new intravascular ultrasound (IVUS)-guided stenting strategy versus angiography on optimal stent expansion (OSE) and procedural outcomes in patients with positive lesion remodeling. There are no IVUS criteria on how to achieve OSE. A total of 100 patients were assigned to a new IVUS-guided stenting strategy (IVUS group) versus angiography-guided stenting (Angio group). In the IVUS group, among patients with positive lesion remodeling, defined as a remodeling ratio (RR; lesion external elastic membrane (EEM) area/distal reference EEM area) >1.05, the stent was expanded with a balloon sized to the distal reference EEM diameter. In the Angio group, the stent was expanded by visual estimation. In both groups, IVUS was performed after postdilation. Minimum stent area (MSA) and stent volume index were significantly larger in the IVUS versus Angio group (7.1 ± 1.9 vs. 5.9 ± 1.5 mm2 , and 8.7 ± 2.1 vs. 7.5 ± 1.8 mm3 /mm, respectively; p < .01). The percentages of OSE, defined as an MSA ≥5.4 mm2 , MSA ≥90% of distal reference lumen area (DRLA), or MSA > DRLA, were significantly higher in the IVUS versus Angio group (80 vs. 56%, 78 vs. 54%, and 71 vs. 38%, respectively; p < .01). Stent underexpansion, malapposition, and residual reference segment stenosis were significantly higher in the Angio versus IVUS group (44 vs. 12%, 16 vs. 4%, and 12 vs. 0%, respectively; p < .05). In the IVUS group, owing to positive remodeling, there was no incidence of dissection or perforation. This new strategy of IVUS-guided stenting in patients with positive lesion remodeling, compared with angiography, significantly increased stent expansion and decreased stent underexpansion, malapposition, and residual reference segment stenosis with no complications.

3047Long-term changes after carotid stenting assessed by intravascular ultrasound and near-infrared spectroscopy

Abstract Background/Introduction Long-term effect of carotid stenting (CAS) on the stabilization of the plaque is not well described. The interaction among the late stent expansion, neointimal hyperplasia, and lipid core might explain stabilization of the plaque and low long-term incidence of stroke after CAS. Purpose To assess long-term change in the lipid signal, stent, and luminal dimensions and restenosis after CAS with the multimodality intravascular ultrasound (IVUS) and near-infrared spectroscopy (NIRS) imaging. Methods We performed follow-up NIRS-IVUS imaging in patients who underwent CAS at our institution. Of the 112 patients (120 carotid arteries) who had NIRS-IVUS during CAS, 96 were alive at the time of the study, and 52 (58 carotid arteries) agreed to participate on the study. The lipid signal of the stented segment was calculated from the NIRS-derived chemogram (a spectroscopic map) as the lipid core burden index (LCBI, a dimensionless number from 0 to 1000). Volumetric calculations were performed using dedicated software with the automated lumen and stent detection and manual corrections. Median time from CAS to the follow-up examination was 31 months (range 5–56). Results The mean (± SD) LCBI significantly decreased from 32±56 to 17±27 (p=0,002). The mean stent volume significantly increased from 717±302 mm3 to 1019±429 mm3 (p&lt;0,001) with mean stent expansion 43±24%. The mean luminal volume increased from 717±302 mm3 to 760±359 mm3 (p=0,025) due to the mean in-stent restenosis (ISR) 26±15% of the stent volume. Significant increase in the mean minimal stent area (MSA) (from 11,1±3,0 mm2 to 15,0±3,5 mm2, p&lt;0,001) was not observed in the minimal luminal area (MLA) (from 11,1±3,0 mm2 to 11,4±4,4 mm2, p=0,098) due to the ISR. Significant restenosis (reduction of MLA ≥50% from baseline) was present in 7 stents. Conclusions During nearly three years of the follow-up after CAS the lipid signal decreased suggesting stabilization of the plaque. Significant late stent expansion was balanced with substantial neointimal hyperplasia therefore the late luminal gain was only modest in volume and nonsignificant at the site of MLA. There was a major variability in the rate of the late stent expansion and restenosis.

Multivariable Analysis of Patients With Severe Persistent Postprocedural Hypotension After Carotid Artery Stenting

Purpose: To assess the incidence and predictors of severe, persistent postprocedural hypotension (PPH) after carotid artery stenting (CAS). Materials and Methods: A total of 146 patients (mean age 72.8 years; 104 men) who underwent 160 CAS procedures using a standardized protocol at 3 vascular centers were retrospectively analyzed. The primary endpoint was postprocedural hypotension, defined as a reduction in systolic blood pressure (SBP) >40 mm Hg from baseline or an SBP of <90 mm Hg sustained for >1 hour after CAS. Potential prognostic factors for postprocedural hypotension were identified and subjected to logistic regression analyses; outcomes are presented as the odds ratios (ORs) with 95% confidence intervals (CIs). Results: PPH developed in 36 (24.7%) patients after 37 (23.1%) CAS procedures. These patients had significantly longer intensive care unit and hospital stays than those who did not develop hypotension (p<0.001). PPH was associated with severe lesion calcification (OR 6.28, 95% CI 1.81 to 21.98, p=0.004) and contrast volume (OR 1.02, 95% CI 1.01 to 1.02, p<0.001). A 4-fold increase in the risk of PPH (OR 4.22, 95% CI 1.38 to 13.33, p=0.012) was found between the embolic protection device most associated with PPH (Angioguard) and the device least associated with PPH (Emboshield NAV6). A similar trend was also observed for the Precise vs Xact stents (OR 6, 95% CI 2.08 to 17.6, p=0.001). Bootstrapped multivariable modeling identified the Precise stent and contrast volume as significant predictors of persistent postprocedural hypotension. Further investigation of the contrast volume revealed associations with sex, severe calcification, arch type, previous coronary artery bypass surgery, and primary stenting, suggesting that the contrast volume reflects the complexity of the procedure. Conclusion: The complexity of the procedure and type of stent may play a role in the development of postprocedural hypotension after CAS.

Extracorporeal shock wave lithotripsy versus ureteroscopy for management of pediatric nephrolithiasis in upper urinary tract stones: multi-institutional outcomes of efficacy and morbidity

As the incidence of pediatric nephrolithiasis rises, understanding the efficacy and morbidity of surgical treatment options is critical. Currently, there are limited comparative data assessing shock wave lithotripsy (SWL) and ureteroscopy (URS) outcomes in children. The objective of this study was to compare stone clearance, 30-day emergency department visits, and the number of general anesthetics required per stone treatment for both modalities. A multi-institutional retrospective review of children presenting for either URS or SWL between 2000 and 2017 was performed. Stone clearance, need for retreatment, the number of anesthetics, as well as the number and reason for emergency room visit were captured and compared between groups. Multivariate statistical analysis accounting for age, stone location, stone diameter, pre-intervention stent, and provider volume was performed for adjusted analysis. A total of 84 SWL and 175 URS procedures were included. Complete stone clearance and rates of residual stone fragments <4mm after final procedure for SWL were 77.0% and 90.8% and for URS were 78.5% and 91.7%, respectively. Retreatment rates for both procedures were not significantly different (17.9% SWL vs. 18.9% URS, P=0.85). Children who underwent SWL had lower rates of emergency room visits for infections (0% vs. 5.1%, P=0.03) and flank pain (3.6% vs. 10.9%, P=0.05)and required fewer general anesthetics per treatment (1.2 vs. 2.0, P<0.01) than those who underwent URS (Figure). Stone clearance after both the initial and final treatmentsand need for repeat interventionswere similar between surgical modalities. However, SWL carries less morbidity than URS. Specifically, patients who underwent SWL experienced lower rates of ED visits for urinary tract infection and for flank pain, parallel to conclusions in current comparative literature. In addition, SWL requires less general anesthetics (2.0 vs. 1.2), secondary to lower rates of ureteral stent placement and removal. Data on the potential risk of general anesthetics to neurodevelopment supportthoughtful utilization of these medications. Limitations of this study include its retrospective natureand the prolonged 20-year time period over which data were collected. When adjusting for confounders, SWL and URS achieve similar stone clearance. In the setting of equivalent efficacy, considerations regarding necessity of repeat interventions, morbidity of anesthesia, and complications should be integrated into clinical practice.

Provider Trends in Atherectomy Volume between Office-Based Laboratories and Traditional Facilities

As patient care is being increasingly transitioned out of the hospital and into the outpatient setting, there is a growing interest in developing office-based angiography suites, that is, office-based laboratories. Office-based care has been associated with increased efficiency and greater patient satisfaction, with substantially higher reimbursement directly to the physicians providing care. Prior studies have demonstrated a shift of revascularization procedures to office-based laboratories with a concomitant increase in atherectomy use, a procedure with disproportionately high reimbursement in comparison to other peripheral revascularization techniques. We sought to determine provider trends in endovascular procedure volume, settings, and shifts in practice over time, specific to atherectomy. Using Centers for Medicare & Medicaid Services Provider Utilization and Payment Data Public Use Files from 2013 to 2015, we identified providers who performed diagnostic angiography (DA), percutaneous transluminal angioplasty (PTA), stent placement (stent), and atherectomy, and procedures were aggregated at the provider level. Trends in procedures performed in office-based laboratory and facility-based settings were analyzed. Atherectomy was specifically analyzed using the total number and proportion of office-based laboratory procedures, and providers were stratified into quintiles by case volume. Between 2013 and 2015, 5,298 providers were identified. Over this time period, the number of providers performing atherectomy increased 25.7%, with the highest quintile of atherectomy providers performing an average of 263 cases (range 109-1,455). The proportion of physicians who performed atherectomy only in the office increased from 39.8% to 50.7% from 2013 to 2015, whereas only 20.8% of physicians who performed DA, PTA, or stent in 2015 did so only in an office-based laboratory. Of the physicians with the highest atherectomy volume, 77.8% operated only in the office in 2015, and these physicians increased their atherectomy volume to 114.1% during the study period. Of those physicians who transitioned to a solely office-based laboratory practice over the study period, atherectomy volume increased 63.4%, which was disproportionate compared with the growth of their DA, PTA, and stent volume. Over this short study period, a rapid shift into the office setting for peripheral intervention occurred, with a concomitant increase in atherectomy volume that was disproportionate to the increase in other peripheral interventions. This increase in office-based laboratory atherectomy occurred in the setting of increased reimbursement for the procedure and despite a lack of data supporting superiority over PTA/stent.

Short-term stent coverage of second-generation zotarolimus-eluting durable polymer stents: Onyx one-month optical coherence tomography study.

IntroductionTo date the early strut coverage with the second-generation durable-polymer ONYX zotarolimus-eluting stent (O-ZES) is unknown.AimOptical coherence tomography (OCT) assessed the strut coverage of O-ZES at thirty-day follow-up.Material and methodsOCT was performed after implantation and at 1-month follow-up in 15 patients treated with O-ZES.ResultsMean patient age was 67 ±7 years (73% males). The clinical presentation consisted of acute coronary syndromes (n = 13) and stable coronary disease (n = 2). Four (26%) patients had diabetes. OCT analysis was performed at baseline and 1-month follow-up in all stents. 378 cross-sections with 3582 struts were assessed at baseline and 3661 at follow-up. At follow-up, 88% struts were covered by tissue with a median thickness 37.91 μm (IQR: 22.32–64.15). Median in-stent area obstruction by neointima was 2.64% (IQR: 1.70–4.84). From the total stent covered area, 92.3% showed complete strut coverage. Homogeneous tissue was observed in 74% of cases. There were no differences in minimal lumen area (5.07 ±1.08 mm2 vs. 4.81 ±0.94 mm2, p = 0.125) or minimal stent area (4.95 ±1.22 mm2 vs. 4.92 ±0.99 mm2) at baseline and at follow-up. There were no differences in the rate of strut malapposition (4.3% vs. 5.7%, p = 0.417). For all stents, malapposition volume was 47.9 mm3 at baseline and 51.7 mm3 at follow-up, giving the late acquired stent malapposition volume of 3.8 mm3.ConclusionsThe second-generation durable polymer O-ZES showed favorable vessel healing at 30-day OCT follow-up.

Prasugrel versus clopidogrel for residual thrombus burden in patients with ST-segment elevation myocardial infarction

Prasugrel was shown to inhibit platelet activity more rapidly and consistently than clopidogrel. We compared the effects of prasugrel and clopidogrel on residual thrombus burden assessed by optical coherence tomography after stent implantation in patients with ST-segment elevation myocardial infarction (STEMI). A total of 76 patients with STEMI undergoing percutaneous coronary intervention (PCI) within 12 h after the onset were retrospectively enrolled. Of them, 34 patients were treated with prasugrel (loading dose, 20 mg) and the remaining 42 with clopidogrel (loading dose, 300 mg). Stent volume and in-stent thrombus volume were assessed by post-PCI optical coherence tomography. Baseline clinical characteristics, angiographic findings, and PCI procedure did not differ between the two groups. There was no difference in in-stent volume between patients with prasugrel and clopidogrel [169 (134-214) versus 166 (128-210) mm, P=0.83]. Patients with prasugrel had a significantly reduced in-stent thrombus volume compared with those with clopidogrel [0.59 (0.16-1.09) vs. 1.08 (0.32-2.30) mm, P=0.03]. The mean area and maximum area of in-stent thrombus were also significantly smaller in prasugrel than in clopidogrel group [0.03 (0.01-0.05) vs. 0.05 (0.01-0.10) mm, P=0.04, and 0.45 (0.27-0.75) vs. 0.77 (0.34-1.23) mm, P=0.03, respectively]. Prasugrel more effectively reduced residual thrombus burden after stent implantation in patients with STEMI, indicating a faster and more potent platelet inhibitory effect of prasugrel compared with clopidogrel.

Abstract 16601: Evaluation of Vascular Response After Balloon Angioplasty for In-Stent Restenosis Assessed by Optical Frequency Domain Imaging

Background and aim: The optimal balloon angioplasty (BA) procedure for in-stent restenosis (ISR) was not established. The aim of this study was to investigate vascular response after BA in ISR lesions using optimal frequency domain imaging (OFDI). Methods and results: This study consisted of 22 ISR lesions that were treated with BA. OFDI analysis were performed for 10mm longitudinal ISR segment including minimum lumen area before and after BA, furthermore morphology of ISR neointimal tissue and volumetric measurements were assessed. We analyzed at 1mm interval cross-sectional OFDI images of lesions before BA, and at every slices per each lesion, the neointimal tissue was divided into 2 morphologic patterns: homogeneous pattern and non-homogeneous pattern. Then, the neointimal tissue morphological characteristics of each lesion was expressed according to “homogeneous ratio”, defined as the number of homogeneous pattern slices divide by a total of slices. In volumetric OFDI measurements, lumen gain rate was calculated as (lumen volume (LV) after BA - LV before BA) / LV before BA, stent expansion rate as (stent volume (SV) after BA - SV before BA) / SV before BA and neointimal volume (NV) reduction rate as (NV before BA -NV after BA) / NV before BA. There was no correlation between homogeneous ratio and lumen gain ratio. There was positive correlation between homogeneous ratio and stent expansion ratio, and there was negative correlation between homogeneous ratio and neointimal volume reduction ratio (figure). Conclusions: OFDI assessment is useful to understand the vascular response by BA for ISR lesions. The mechanism of lumen gain in BA procedure for ISR lesions with homogeneous tissue is mainly obtained by stent expansion, whereas for lesions with non-homogeneous tissue is by neointimal tissue compression.