Open-cell design stents in congenital heart disease: a comparison of IntraStent vs. Palmaz stents

A New Solution for Stenting Large Right Ventricular Outflow Tracts Before Transcatheter Pulmonary Valve Replacement

BACKGROUND

Prestenting right ventricular outflow tracts (RVOTs) before transcatheter pulmonary valve replacement (TPVR) is essential. Optimus-XXL (AndraTec GmbH, Koblenz, Germany) is a new extra-large, balloon-expandable cobalt-chrome stent with promising technologies.

METHODS

From June 2020 to November 2020, 15 patients with congenital heart disease, dysfunctional RVOTs and target TPVR diameter ≥ 23 mm received Optimus-XXL stents before proceeding to TPVR using the SAPIEN valve (Edwards Lifesciences, Irvine, CA). Standard safety and outcomes were prospectively assessed.

RESULTS

Patients' median age and weight were 25.8 years (range: 10.5-63.1 years) and 58 kg (range: 43.8-101 kg), respectively. Underlying diagnosis was tetralogy of Fallot (66.7%), and RVOTs were patched (80%). Fifteen bare-metal stents were implanted using femoral (n = 14) and jugular approaches (n = 1). One conduit rupture was immediately controlled with a covered Optimus-XXL. Median stent length was 43 mm (range: 33-57 mm), and median target expansion diameter was 28 mm (range: 23-30 mm). Two procedural incidents occurred during stent delivery and were percutaneously treated. Stent stability was documented during TPVRs immediately performed in 14 patients. Median stent shortening was 13.7%, and median percentage of intended stent expansion was 95.9%. There was no stent fracture on the short-term follow-up (median: 4.5 months).

CONCLUSIONS

We report the first implantations of Optimus-XXL stents in dysfunctional RVOTs with excellent preliminary results. Optimus-XXL should be considered as a valuable adjunct in the armamentarium for routine and complex TPVR procedures.

Edwards SAPIEN XT transcatheter pulmonary valve implantation: 5-year follow-up in a French Registry

OBJECTIVES

This study sought to investigate patient intermediate-term outcomes after transcatheter pulmonary valve replacement (TPVR) with Edwards SAPIEN valve.

BACKGROUND

The Edwards SAPIEN valve, initially designed for percutaneous aortic valve replacement, has been approved for TPVR in patients with dysfunctional right ventricular outflow tracts (RVOT), but only short-term follow-up has been reported.

METHODS

From 2011 to 2016, 62 patients undergoing successful TPVR using the SAPIEN XT valve were consecutively included into the study. Primary efficacy and safety endpoints were defined as freedom from valve-reintervention and freedom from infective endocarditis at last follow-up, respectively.

RESULTS

The primary efficacy outcome was met for 87.1% patients after a mean follow-up of 4.6 ± 1.8 years, corresponding to a freedom of reintervention at 5 years of 89% (95% CI 74.8-95.6%). Reinterventions were exclusively due to recurrent obstruction, no significant valvular regurgitation was observed. One case of infective endocarditis was reported, corresponding to a rate of 0.35% per patient-year (95% CI 0.01-2.00%). At 5 years, freedom from infective endocarditis was 98.4% (95% CI 89.1-99.8%). Six patients died or were transplanted due to advanced cardiac failure, without relationship with TPVR. In univariate analysis, reintervention was associated with young age, a smaller tube-graft, a higher pulmonary valve gradient after the procedure and a ratio of largest implanted stent diameter to invasive balloon conduit diameter over 1.35.

CONCLUSIONS

This study documents the mid-term safety and efficacy of the Edwards SAPIEN XT valve in patients with dysfunctional RVOT, and identifies a patient profile associated with an uncertain benefit-risk balance.

Transcatheter Intervention for Congenital Defects Involving the Great Vessels: JACC Review Topic of the Week

Since the development of balloon angioplasty and balloon-expandable endovascular stent technology in the 1970s and 1980s, percutaneous transcatheter intervention has emerged as a mainstay of therapy for congenital heart disease (CHD) lesions throughout the systemic and pulmonary vascular beds. Congenital lesions of the great vessels, including the aorta, pulmonary arteries, and patent ductus arteriosus, are each amenable to transcatheter intervention throughout the lifespan, from neonate to adult. In many cases, on-label devices now exist to facilitate these therapies. In this review, we seek to describe the contemporary approach to and outcomes from transcatheter management of major CHD lesions of the great vessels, with a focus on coarctation of the aorta, single- or multiple-branch pulmonary artery stenoses, and persistent patent ductus arteriosus. We further comment on the future of transcatheter therapies for these CHD lesions.

Endovascular treatment of the vertebral artery origin stenosis by using the closed-cell, self-expandable Carotid Wallstent

BACKGROUND

Endovascular treatment has been considered a good alternative to surgery for symptomatic vertebral artery origin stenosis (VAOS) due to the high risk of morbidity associated with surgery. The purpose of this study was to evaluate the feasibility and efficacy of insertion of the closed-cell, self-expandable Carotid Wallstent for the treatment of VAOS.

METHODS

The records of 72 patients with VAOS refractory to adequate medication who were treated by endovascular treatment with the Carotid Wallstent from December 2006 to November 2018 were retrospectively evaluated.

RESULTS

Of the 72 patients, 43 presented with transient ischemic attacks. Forty-seven patients (65.3%) manifested other brachiocephalic stenoses; of these, 40 patients had occlusion, hypoplasia, or stenosis of the contralateral vertebral artery. Overall technical success (defined as 20% or less residual stenosis) was 100%. Procedure-related complications (n = 8, 11.1%) included sudden asystole (n = 1), acute in-stent thrombosis (n = 3), minor stroke (n = 3), and stent shortening (n = 1). All complications were resolved without permanent neurological deficit. Angiographic follow-up (mean, 13.0 months) was achieved in 49 patients and revealed in-stent restenosis in 1 patient (2.0%) and stent malposition by shortening in 2 patients (4.1%). Follow-up records were available in 57 patients (mean 15.6 months). Three of the 57 patients (n = 3, 5.3%) had recurrent symptoms of vertebrobasilar ischemia and none was retreated.

CONCLUSIONS

Endovascular treatment of symptomatic VAOS using the closed-cell, self-expandable Carotid Wallstent is technically feasible and effective in alleviating patient symptoms and for improving vertebrobasilar blood flow.

Right ventricular outflow tract prestenting with AndraStent XXL before percutaneous pulmonary valve implantation

BACKGROUND

The indications for percutaneous pulmonary valve implantation (PPVI) have been extended to include large dysfunctional right ventricular outflow tracts (RVOTs). Prestenting of the RVOT is commonly performed before PPVI in order to ensure a stable landing zone. The AndraStent XXL (AndraMed GmbH, Reutlingen, Germany), a cobalt-chromium stent with semi-open cell design, has unique mechanical properties in this indication but is no longer available in France.

AIMS

To assess the efficiency of AndraStent XXL before PPVI.

METHODS

In this retrospective multicentre cohort study, 86 AndraStents XXL were implanted in 77 patients in 6 centres.

RESULTS

PPVI was indicated mainly for pulmonary regurgitation (75.3%) in native or patched RVOT (88.3%). The stents were manually mounted on balloon catheters and delivered through sheaths using a conventional femoral approach. PPVI was performed successfully in 97.4% of patients after successful prestenting, generally during the same procedure (77.9%). There were no deaths associated with stent implantation, and four patients experienced five complications, mainly stent embolization, including one requiring surgery. Neither stent fracture nor dysfunction were observed in any patient during a mean follow-up of 19.2±8.7months. Stent analysis showed an excellent maximal stent expansion (97.1%) regardless of balloon size. A 22.3%±3.4 stent shortening with a 30mm balloon was observed.

CONCLUSIONS

Implantation of large cobalt-chromium AndraStent XXL stents is efficient for prestenting before PPVI.

Dilating and fracturing side struts of open cell stents frequently used in pediatric cardiac interventions-An in vitro study

Background

Open cell stents are frequently used in interventional therapy of congenital heart disease. Overstenting of vessel branches may necessitate strut dilation.

Methods and Results

The strut size achievable in Bard Valeo and Cook Formula stents, and the pressure necessary to fracture struts was assessed. In addition, a self expanding stent (Optimed SinusflexDS) was also tested. With the original balloon at nominal pressure, in Valeo stents side struts could be dilated to approximately 90% of the nominal stent diameter, in Formula stents to approximately 80%. With larger high pressure woven balloons, strut size increased to approximately 125% in Valeo stents, and to approximately 105% in the Formula. Strut fracture can connect two adjoining struts. Pressures were dependent on the balloon utilized. Sidestruts of the Sinusflex could lastingly overdilated with large balloons only.

Conclusion

Dilation and overdilation of side struts in open cell stents can be achieved. Dependent on the clinical context, the original balloon used to place the premounted stent can be used to achieve strut dilation, but woven high pressure balloons maybe safer for patients. Should a larger diameter be required, these high pressure woven balloons can achieve bigger diameters and even strut fracture.

Serial Versus Direct Dilation of Small Diameter Stents Results in a More Predictable and Complete Intentional Transcatheter Stent Fracture: A PICES Bench Testing Study

Balloon-expandable stents, implanted in infants and children with congenital heart disease (CHD), often require redilation to match somatic growth. Small diameter stents may eventually require longitudinal surgical transection to prevent iatrogenic vascular stenosis. Intentional transcatheter stent fracture (TSF) is an emerging alternative approach to stent transection, but little is known about the optimal stent substrate and best protocol to improve the likelihood of successful TSF. Bench testing was performed with a stent dilation protocol. After recording baseline characteristics, stents were serially or directly dilated using ultra-high-pressure balloons (UHPB) until fracture occurred or further stent dilation was not possible. Stent characteristics recorded were as follows: cell design, metallurgy, mechanism, and uniformity of fracture. Stents tested included bare-metal coronary stents, premounted small diameter stents, and ePTFE-covered small diameter premounted stents. Ninety-four stents representing 9 distinct models were maximally dilated, with 80 (85%) demonstrating evidence of fracture. Comprehensive fracture details were recorded in 64 stents: linear and complete in 34/64 stents (53.1%), linear and incomplete in 9/64 stents (14.1%), transverse/complex and complete in 6/64 stents (9.4%), and transverse/complex and incomplete in 15/64 stents (23.4%). Stent fracture was not accomplished in some stent models secondary to significant shortening, i.e., "napkin-ring" formation. Serial dilation resulted in evidence of fracture in 62/67 (92.5%) stents compared with 18/27 (66.7%) stents in the direct dilation group (p = 0.003). Intentional TSF is feasible in an ex vivo model. Serial dilation more reliably expanded the stent and allowed for ultimate stent fracture, whereas direct large diameter dilation of stents was more likely to generate a "napkin-ring" configuration, which may be more resistant to fracture. In vivo animal and human testing is necessary to better understand the response to attempted TSF for newly developed stents as well as those currently in use.

Use of the AndraStent XL and XXL for the treatment of coarctation of the aorta in children and adults: immediate and midterm results

AIMS

The aim of this study is to present our experience with a new type of extra-large stent, namely the AndraStent XL/XXL.

METHODS AND RESULTS

AndraStents were implanted in 46 patients, 38 with native coarctation of the aorta (CoA) and eight with recurrent coarctation of the aorta following previous surgery (ReCoA). All patients had arterial hypertension in the upper limbs, absent or weak femoral pulses, and continuous flow in the abdominal aorta on Doppler examination. The median age of patients was 25 years (range from nine to 65). The stents (cobalt-chromium with semi-open cell design) were manually mounted on balloon catheters and delivered through 10 to 14 Fr Mullins sheaths using a conventional femoral approach. All procedures were successful (no stent migration, proper expansion, no aorta dissection/rupture, major bleeding or major vessel injury). The systolic gradient across the aorta decreased from 40.6 mmHg before the procedure to 11.6 mmHg after the procedure (p<0.001). The mean fluoroscopy time was 5.7 minutes. Imaging examinations were scheduled and performed between six and 12 months after the initial procedure in 40 patients (angiography or angio CT or both). Procedural outcome remained favourable during a mean 2.4 years of follow-up. Neither stent fracture nor dislocation was observed in any patient at follow-up. In two patients, small aneurysm formation was observed six and eight months after the procedure -they were treated successfully with subsequent covered stent implantation. Re-dilatation of the implanted stent was performed between four and 26 months in 14 patients.

CONCLUSIONS

Implantation of new large cobalt-chromium stents is a good therapeutic option for the treatment of native and recurrent CoA.

Simultaneous Kissing Stenting: A Valuable Technique for Reconstructing the Stenotic Initial Segment of the Right Subclavian Artery

Atherosclerotic stenosis or occlusion often involves the subclavian artery. For lesions that are close to the orifice of the right subclavian artery, stenting of the right subclavian artery itself blocks the pathway from the innominate artery to the right carotid artery and causes problems in patients with multiple angiostenosis, especially involving the right carotid system. In this study, we report 2 cases using simultaneous kissing stenting (SKS) of the right subclavian artery and the right carotid artery to relieve right subclavian stenosis and maintain right carotid system patency. Standard stenting methods were used to perform SKS. Two self-expanding stents were implanted simultaneously into the initial segment of the right subclavian artery and the right carotid artery, forming a "Y" shape, with the overlap of the proximal segments in the innominate artery ≥5 mm. After SKS, the stenosed right subclavian artery was dilated, and the patency of the right carotid system was maintained. The symptoms of patients were relieved and the stents were intact at several months of follow-up. In conclusion, SKS of the right subclavian artery and the right carotid artery might be a safe and effective procedure when the stenotic or occlusive lesion in the initial segment of the right subclavian artery is close to the orifice, and lesions (or potential ones) exist in the right carotid system.

Bronchoscopic guidance of endovascular stenting limits airway compression

OBJECTIVE

Bronchial compression as a result of pulmonary artery and aortic arch stenting may cause significant respiratory distress. We set out to limit airway narrowing by endovascular stenting, by using simultaneous flexible bronchoscopy and graduated balloon stent dilatation, or balloon angioplasty to determine maximum safe stent diameter.

METHODS

Between August 2010 and August 2013, patients with suspected airway compression by adjacent vascular structures, underwent CT or a 3D rotational angiogram to evaluate the relationship between the airway and the blood vessels. If these studies showed close proximity of the stenosed vessel and the airway, simultaneous bronchoscopy and graduated stent re-dilation or graduated balloon angioplasty were performed.

RESULTS

Five simultaneous bronchoscopy and interventional catheterization procedures were performed in four patients. Median age/weight was 33 (range 9-49) months and 14 (range 7.6-24) kg, respectively. Three had hypoplastic left heart syndrome, and one had coarctation of the aorta (CoA). All had confirmed or suspected left main stem bronchial compression. In three procedures, serial balloon dilatation of a previously placed stent in the CoA was performed and bronchoscopy was used to determine the safest largest diameter. In the other two procedures, balloon testing with simultaneous bronchoscopy was performed to determine the stent size that would limit compression of the adjacent airway. In all cases, simultaneous bronchoscopy allowed selection of an ideal caliber of the stent that optimized vessel diameter while minimizing compression of the adjacent airway.

CONCLUSION

In cases at risk for airway compromise, flexible bronchoscopy is a useful tool to guide endovascular stenting. Maximum safe stent diameter can be determined without risking catastrophic airway compression.

Coarctation of the aorta: management, indications for intervention, and advances in care

OPINION STATEMENT

Coarctation of the aorta (CoAo) accounts for 9 % of congenital heart defects. Balloon angioplasty has been the conventional endovascular treatment of choice for both native and recurrent coarctation in adults. Recent advancement in stent technology with the development of the covered stents has enhanced the scope for percutaneous management of both native CoAo and post-surgical CoAo. Stent implantation provides better hemodynamic results with larger acute diameter gain and better long-term hemodynamic benefit. Stenting also decreases the incidence of aneurysm formation. The development of biodegradable stents may revolutionize the percutaneous management of coarctation, as the degradation of the stent scaffold within 6 months of implantation will further decrease the incidence of restenosis. In the future stenting may suffice and obviate the need for open repair. Until then, surgical repair of CoAo is the preferred method in both infants and complicated lesions, leaving stenting to adults with focal and uncomplicated disease.

Medium and long-term outcomes after bilateral pulmonary artery stenting in children and adults with congenital heart disease

Percutaneous stenting of branch pulmonary arteries (PAs) has become an important interventional therapy in the complete management of congenital heart disease. Few data exist on long-term outcomes for patients requiring placement of bilateral stents. This study aimed to determine the medium- to long-term outcomes after bilateral stenting of branch PAs in patients with congenital heart disease. A retrospective study analyzed all procedural and follow-up data on patients undergoing bilateral PA stenting during a single procedure. From October 2001 to May 2012, 26 patients underwent bilateral PA stenting (total of 62 stents). The mean age of these patients was 9.5 ± 12 years, and their mean weight was 27 ± 19 kg. The mean procedural time was 191 ± 67 min, and the mean fluoroscopy time was 50 ± 29 min. The mean gradient across the right pulmonary artery decreased from 35 ± 22 to 11 ± 12 mmHg (p < 0.001). The left pulmonary artery gradient decreased from 32 ± 17 to 10 ± 12 mmHg (p < 0.001), and the right ventricle to descending aorta pressure ratio decreased from 71 ± 18 % to 46 ± 13 % (p < 0.001). Intraprocedural adverse events were encountered in four patients (1 small PA dissection, 2 intraprocedural arrhythmias, and 1 first-degree burn on the thigh). The mean follow-up period was 41 ± 23 months. Two deaths occurred. Further interventions were required for 12 patients. Bilateral PA stenting is effective and safe, with an instantaneous significant decrease in pressure gradients. The need for reintervention is common, so continued follow-up assessment is warranted.

Large-diameter graft-stent (Advanta V12) implantation in various locations: early results

OBJECTIVES

Transcatheter stent placement carries the risk of cardiovascular aneurysm or rupture. Covered stent implantation reduces these risks. The recently marketed Advanta V12 large-diameter-covered stent is pre-mounted and requires 9 (8)-11 Fr delivery systems. The aim was to report on the early results of the treatment of various cardiovascular obstructions by the implantation of a new polytetrafluoroethylene-covered stent (V12).

METHODS

Graft stents on balloons with a diameter (12, 14, 16 millimetres) sufficient to anchor the stent in various obstructions (congenital aortic coarctation, n = 5; obstruction after ascending aorta repair, n = 2; pulmonary arteries, n = 5; inferior caval vein, n = 1; atretic superior caval vein, n = 1; pulmonary vein obstruction, n = 1; and right ventricular outflow tract, n = 1) were implanted using the smallest available delivery system. Secondary dilation with larger-diameter balloons was performed when the residual pressure was gradient, the stent-vessel wall relationship or stent re-coiling due to different reasons needed a re-intervention by pure ballooning or second stent placement.

RESULTS

All 16 patients aged 5-46 years underwent V12 implantation. The variability of the treated lesions and the need for additional interventions were responsible for large ranges in fluoroscopy time between 7.3 to 48.2 minutes (median 17.3). Considering the additional procedures, the V12 stent achieved the desired result in all cases. There were no major complications. At short-term median follow-up of 2 months, all patients are alive and well with no evidence of stent failing.

CONCLUSION

These initial results show that the covered Advanta V12 large-diameter stent is safe and effective in the immediate treatment of various cardiovascular obstructions. Long-term follow-up is required.

The role of stents in the treatment of congenital heart disease: Current status and future perspectives

Intravascular or intracardiac stenoses occur in many forms of congenital heart disease (CHD). Therefore, the implantation of stents has become an accepted interventional procedure for stenotic lesions in pediatric cardiology. Furthermore, stents are know to be used to exclude vessel aneurysm or to ensure patency of existing or newly created intracardiac communications. With the further refinement of the first generation of devices, a variety of "modern" stents with different design characteristics have evolved. Despite the tremendous technical improvement over the last 20 years, the "ideal stent" has not yet been developed. Therefore, the pediatric interventionalist has to decide which stent is suitable for each lesion. On this basis, currently available stents are discussed in regard to their advantages and disadvantages for common application in CHD. New concepts and designs developed to overcome some of the existing problems, like the failure of adaptation to somatic growth, are presented. Thus, in the future, biodegradable or growth stents might replace the currently used generation of stents. This might truly lead to widening indications for the use of stents in the treatment of CHD.

Stent fracture in revascularization for symptomatic ostial vertebral artery stenosis

INTRODUCTION

We assessed the long-term follow-up examinations and complications of percutaneous transluminal angioplasty and stenting (PTAS) for symptomatic ostial vertebral artery (VA) stenosis.

METHODS

A retrospective study was done to evaluate 12 patients with symptomatic ostial VA stenosis who underwent PTAS. Six patients were treated with the Palmaz stent and six with a balloon-expandable coronary stent. Initial angiographic follow-up examination was conducted about 12 months after PTAS in all patients. Simple radiographic, ultrasonographic and clinical follow-up examinations were scheduled every 6 months.

RESULTS

Excellent dilatation was achieved in all patients without any procedural complications. Initial angiographic follow-up obtained at a mean of 13 months after PTAS detected no restenosis. However, an asymptomatic severe restenosis was detected at 24 months after PTAS in one patient (8%). During a mean follow-up of 31.5 months, three stent fractures were detected in deployed coronary stents (50%). None of the stent fractures was associated with either recurrent stroke or restenosis. No patients developed recurrent symptoms during the follow-up period.

CONCLUSION

PTAS for symptomatic ostial VA stenosis is effective in preventing recurrent stroke. As the open-cell single-joint type of stent is associated with the risk of fracture, long-term follow-up examinations including simple radiography are needed.

Axial stent strut angle influences wall shear stress after stent implantation: analysis using 3D computational fluid dynamics models of stent foreshortening

INTRODUCTION

The success of vascular stents in the restoration of blood flow is limited by restenosis. Recent data generated from computational fluid dynamics (CFD) models suggest that the vascular geometry created by an implanted stent causes local alterations in wall shear stress (WSS) that are associated with neointimal hyperplasia (NH). Foreshortening is a potential limitation of stent design that may affect stent performance and the rate of restenosis. The angle created between axially aligned stent struts and the principal direction of blood flow varies with the degree to which the stent foreshortens after implantation.

METHODS

In the current investigation, we tested the hypothesis that stent foreshortening adversely influences the distribution of WSS and WSS gradients using time-dependent 3D CFD simulations of normal arteries based on canine coronary artery measurements of diameter and blood flow. WSS and WSS gradients were calculated using conventional techniques in ideal (16 mm) and progressively foreshortened (14 and 12 mm) stented computational vessels.

RESULTS

Stent foreshortening increased the intrastrut area of the luminal surface exposed to low WSS and elevated spatial WSS gradients. Progressive degrees of stent foreshortening were also associated with strut misalignment relative to the direction of blood flow as indicated by analysis of near-wall velocity vectors.

CONCLUSION

The current results suggest that foreshortening may predispose the stented vessel to a higher risk of neointimal hyperplasia.

Late distortion of the original Palmaz stent implanted in postoperative lesions associated with congenital heart disease

The objective of this study was to report late distortion of a Palmaz stent. Late distortion of an original Palmaz stent, implanted in an extracardiac lesion, is rare. We completed a 1-year follow-up of 54 patients who had been implanted with 80 Palmaz stents in extracardiac lesions. Distortion of two stents was detected in two patients. For case 1, we implanted a P188 stent for supravalvar pulmonary stenosis complicating an arterial switch operation in a 14-year-old girl. Seven months later, we found compression of the stent. Although we implanted two P308 stents anterior to the distorted stent, distortion of both stents developed after 1 month. Two more P308 stents placed inside each stent were gradually recompressed. A CAT scan showed compression of the stent by a dilated sinus of valsalva. For case 2, we implanted a P308 stent for stenosis of the superior vena cava after Williams operation in an 11-year-old boy. A chest X-ray documented longitudinal compression of the stent 27 months after implantation and a CAT scan showed the ascending aorta was in contact with the stent. A Palmaz stent may be distorted when implanted in a lesion adjacent to a pulsating aorta.

Stent design properties and deployment ratio influence indexes of wall shear stress: a three-dimensional computational fluid dynamics investigation within a normal artery

Restenosis limits the effectiveness of stents, but the mechanisms responsible for this phenomenon remain incompletely described. Stent geometry and expansion during deployment produce alterations in vascular anatomy that may adversely affect wall shear stress (WSS) and correlate with neointimal hyperplasia. These considerations have been neglected in previous computational fluid dynamics models of stent hemodynamics. Thus we tested the hypothesis that deployment diameter and stent strut properties (e.g., number, width, and thickness) influence indexes of WSS predicted with three-dimensional computational fluid dynamics. Simulations were based on canine coronary artery diameter measurements. Stent-to-artery ratios of 1.1 or 1.2:1 were modeled, and computational vessels containing four or eight struts of two widths (0.197 or 0.329 mm) and two thicknesses (0.096 or 0.056 mm) subjected to an inlet velocity of 0.105 m/s were examined. WSS and spatial WSS gradients were calculated and expressed as a percentage of the stent and vessel area. Reducing strut thickness caused regions subjected to low WSS (<5 dyn/cm2) to decrease by ∼87%. Increasing the number of struts produced a 2.75-fold increase in exposure to low WSS. Reducing strut width also caused a modest increase in the area of the vessel experiencing low WSS. Use of a 1.2:1 deployment ratio increased exposure to low WSS by 12-fold compared with stents implanted in a 1.1:1 stent-to-vessel ratio. Thinner struts caused a modest reduction in the area of the vessel subjected to elevated WSS gradients, but values were similar for the other simulations. The results suggest that stent designs that reduce strut number and thickness are less likely to subject the vessel to distributions of WSS associated with neointimal hyperplasia.