Balloon-expandable Bare Metal Stent Research Articles

The efficacy and safety of different endovascular modalities for infrapopliteal arteries lesions: A network meta-analysis of randomized controlled trials

Endovascular treatment has become the first-line therapy for infrapopliteal artery occlusive disease (IPOD), while the optimal endovascular method remains to be determined. We performed a network meta-analysis (NWM) of randomized controlled trials (RCTs) to simultaneously compare the outcomes of different endovascular modalities for IPOD. The Pubmed, Embase, and Cochrane databases were used as data sources. The NWM approach used random-effects models based on the frequentist framework. In total, 22 eligible RCTs (44 study arms; 1,348 patients) involving nine endovascular modalities or combinations [balloon angioplasty (BA), drug-coated balloon (DCB), drug-eluting stent (DES), atherectomy device + BA (AD + BA), AD + DCB, balloon-expandable bare metal stent (BMS), self-expanding stent (SES), absorbable metal stents (AMS), and inorganics-coated stent (ICS)] were included. BA had a lower 12-month primary patency rate than DCB (RR 0.50, CI 0.27, 0.93) and AD + DCB (RR 0.34, CI 0.12, 0.93). AD + DCB decreased 6-month TLR compared with AMS (RR 0.15, CI 0.03, 0.90), and DES decreased it compared with BMS (RR 0.25, CI 0.09, 0.71). DCB had a lower 6-month TLR rate than AMS (RR 0.26, CI 0.08, 0.86) and BA (RR 0.51, CI 0.30, 0.89). BA had a higher 12-month TLR rate than DCB (RR 1.76, CI 1.07, 2.90). According to the value of the surface under the cumulative ranking curve (SUCRA), AD + DCB was considered the best treatment in terms of primary patency at 6 months (SUCRA = 87.5) and 12 months (SURCA = 91). AD + BA was considered the best treatment in terms of 6-month TLR (SUCRA = 83.1), 12-month TLR (SURCA = 75.8), and 12-month all-cause mortality (SUCRA = 92.5). In terms of 12-month major amputation, DES was considered the best treatment (SUCRA = 78.6), while AD + DCB was considered the worst treatment (SUCRA = 28.8). Moreover, AD + BA always ranks higher than AD + DCB in the comparison including these two combinations. Subgroup analyses of modalities without stenting did not significantly change the primary outcomes. ADs showed noteworthy advantages in multiple terms for IPOD except for 12-month major amputation. AD + BA may be a better method for IPOD than AD + DCB. The efficacy and safety of ADs are worthy of further investigation. [https://www.crd.york.ac.uk/prospero/], identifier [CRD42022331626].

Coil Embolization Of Persistent Type 1 Endoleak

Type I endoleak is a well-known complication of endovascular repair which could be due to the patient or technical factors during the procedure. Every type I or type III endoleak should be repaired prior to completion of the endovascular repair procedure. In the case of type I endoleak aneurysm, the sac is still pressurized and will grow over time. Every attempt should be made to resolve endoleak prior to the completion of the procedure. Available strategies to treat type I endoleak include: (1) Repeat angioplasty of the seal zone; (2) Addition of an aortic cuff; (3) Use of balloon-expandable bare-metal stents to increase the radial force; (4) Use of endoanchors to obtain better graft/aorta apposition; (5) Extension of the graft with snorkel or fenestrated endograft to extend the seal zone beyond the visceral branches; and (6) Explantation and open repair.

Bronchial stenting in infants with severe bronchomalacia: Technique and outcomes

ObjectivesTo report the first use of a balloon expandable bare metal stent for treating infant bronchomalacia. BackgroundInfant bronchomalacia often requires prolonged mechanical ventilation and can be life-threatening. Effective treatment for severe infant bronchomalacia continues to be elusive. We present three cases of bronchial stenting for no-option or treatment refractory infant bronchomalacia. MethodsThree consecutive cases of stenting to relieve conservative treatment refractory severe infant bronchomalacia were performed between February 2019 and December 2020. Initial diagnosis was confirmed with Computed Tomography (CT) angiography. Patients underwent rigid micro laryngoscopy, bronchoscopy, and flexible bronchoscopy to evaluate the airway. Initial conservative management strategies were pursued. Patients failing initial conservative management strategies were considered for rescue bronchial stenting. ResultsOur initial clinical experience with a coronary bare metal stent for these procedures has been favorable. The stent was easy to deploy with precision. We did not encounter stent embolization or migration. There was sufficient stent radial strength to relieve bronchomalacia without causing restenosis or erosion. There was no significant granulation tissue formation. In one patient, the stent was removed after 12 months of somatic growth; this was uneventful and bronchial patency was maintained. There were no complications in any of our patients regarding stent placement and reliability. ConclusionIn cases of three infants with severe bronchomalacia, we found that bronchial stenting with the bare metal coronary stent was effective in relieving bronchial stenosis.

Midterm results of kissing stent reconstruction of the aortoiliac bifurcation.

PurposeOne subset of peripheral arterial disease is aortoiliac occlusive diseases (AIOD). AIOD is the term for all arterial lesions between the infrarenal distal aorta and common femoral artery. Implantation of kissing stents (KS) with covered stents (CS), bare-metal stents (BMS) is one of the endovascular treatment (ET) modalities for AIOD involving aortic bifurcation. In this study, we report the outcomes of the KS technique in infrarenal AIOD.MethodsBetween January 2014 and September 2017, 31 patients who underwent ET were treated with KS technique either with balloon-expandable BMS or balloon-expandable CS. Technical details, clinical success, complications, and patency at follow-up were documented.ResultsThe majority of patients were male (77.4%), and the median age was 62 years (range, 45–78 years). All patients were classified according to the TASC II criteria. Eight patients (25.8%) were classified as TASC B. Fifteen patients (48.4%) were classified as TASC C, and 8 patients (25.8%) were classified as TASC D. These 23 patients were classified as complex AIOD group. BMS was used in 17 patients (54.8%), and CS was used in 14 patients (45.2%). Technical and clinical success was achieved in 100% of treated cases. The median follow-up was 24 months (range, 24–34 months). Primary patency rates at 12, 18, and 24 months after ET were 100%, 96.8%, and 90.3%, respectively.ConclusionWe found that the KS technique has satisfying 24-month results, even in complex AIOD lesions, with high technical success and acceptable midterm patency. Key Words: Aorta, Arterial occlusive diseases, Endovascular procedures, Iliac artery, Stents

Mid-term outcomes with adult endovascular treatment of coarctation of the aorta

BackgroundThis study examines the contemporary medium- and long-term outcomes of endovascular repair of aortic coarctation in the adult. MethodsWe reviewed the clinical and imaging data of 56 consecutive adult patients with aortic coarctation who underwent endovascular repair at the Mazankowski Alberta Heart Institute, Edmonton, Alberta, Canada, from 2003 to 2018. ResultsThere were 20 (35.7%) female and 36 (64.3%) male patients (including 9 re-intervention cases) with a mean age of 33.6 ± 13.6 years. Thirty-seven (66.1%) were treated with balloon-expandable covered stent and 12 (21.4%) were treated with balloon-expandable bare-metal stent. Pressure gradients decreased from baseline level of 27.99 ± 12.75 (8–70) mm Hg to 5.33 ± 4.42 (0–17.5) mm Hg following the procedure. There were 2 (3.6%) procedure related complications (aortic dissection [n = 1] and stent malposition [n = 1]). During a median (Q1 - Q3) follow up of 5.36 (2.28–7.58) years, 2 deaths (4.2%) and 9 (19%) re-interventions occurred, and the overall survival was 95.8%. ConclusionPercutaneous coarctoplasty, with either covered or bare metal stents, is a safe and durable option for aortic coarctation repair with excellent long-term survival.

Bare Stents for Iliac Chronic Total Occlusions (“TELIS”): A Prospective Cohort Study with a Midterm Follow-up

This study aims to assess primary bare stenting for iliac chronic total occlusions (CTOs) with midterm follow-up. From April 2013 to May 2016, all patients presenting with symptomatic iliac CTO were treated endovascularly and included in a prospective single-center cohort. Common iliac CTOs were treated with balloon-expandable bare-metal stents. External iliac lesions were treated with bare self-expandable nitinol stents. Primary end point was primary sustained clinical improvement. A total of 49 iliac CTOs were treated in 46 patients. A total of 22 lesions were located at the level of the common iliac artery (45%), 20 at the external iliac artery (41%), and 7 extending to both (14%). Mean stenting length was 114.4±49.8mm. Technical success was 98%. Primary sustained clinical improvement was achieved for 93.4±3.7% of patients at 12months and 87.7±5.2% at 24months. Three in-stent thrombosis were observed with no restenosis in the remaining patients at 24months. Freedom from target lesion revascularization was 93.3%±3.7% at 24months. Three stent fractures were noted, none were symptomatic. Mean quality of life (EQ5D-3L) was significantly improved at 24months (71.2±20.3 vs. 52.4±22.6, P=0.001). Our results showed that primary bare-metal stenting for iliac CTO is safe and efficient at 24months and could be considered as a first-line strategy.

Long-Term Outcome of Chimney Technique Using a Balloon-Expandable Bare-Metal Stent to Preserve Supra-Arch Branches in Type B Aortic Dissection.

This study was performed to investigate the long-term effect of chimney technique using balloon-expandable bare-metal stents (BMSs) to preserve the supra-arch branches in type B aortic dissection (TBAD). Fifty patients with TBAD treated by thoracic endovascular aortic repair with the chimney technique (chTEVAR) using balloon-expandable BMSs from July 2009 to December 2013 were retrospectively assessed. Follow-up computed tomography angiography was performed to assess the postoperative outcomes. The primary end point was a persistent type Ia endoleak (ELIa). The secondary endpoints were chimney stent (CS)-based complications (stenosis, occlusion, fracture, or transposition), all-cause mortality, reintervention, and stroke. Fifty supra-arch branches (left common carotid artery, n = 11; left subclavian artery, n = 39) were preserved via the chimney technique with 50 balloon-expandable BMSs. The technical success rate was 100%. An immediate ELIa was discovered in 9 (18%) patients. The median survival duration during follow-up was 77.3 months. Five (10%) patients had a persistent ELIa; 3 of these patients had an immediate ELIa. Asymptomatic CS-based complications were found in 3 (6%) patients. The all-cause mortality rate was 8% (4/50); 2 deaths were aortic-related deaths. Five (10%) patients underwent a reintervention. During the estimated 36-month survival period, the survival rate, the rate of freedom from persistent ELIa, and the rate of freedom from reintervention were 93.87%, 89.48%, and 95.56%, respectively. The long-term outcomes showed that chTEVAR using balloon-expandable BMSs was safe and feasible for preservation of the supra-arch branches. Evaluation of more patients with a longer follow-up period is needed.

Mid-term results of in situ fenestration stented with balloon-expandable bare metal stents during thoracic endovascular aortic repair.

To assess the safety, feasibility and effectiveness of balloon-expandable bare metal stents (BMS) as bridge stents during thoracic endovascular aortic repair (TEVAR). Retrospective analysis was conducted on 103 consecutive patients who underwent TEVAR procedures from December 2015 to March 2018. Thirty-one patients fulfilled requirements for inclusion and exclusion in the analysis. Thirty-three in situ fenestration (ISF) procedures (single fenestration [n = 29]; dual fenestration [n = 2]) were performed in the 31 patients (67.7% men; median age, 61.5 year) who underwent TEVAR for thoracic lesions (aortic dissection [n = 23], aortic aneurysm [n = 3], aortic ulcer [n = 5]) with 34 stents (33 balloon-expandable BMS, 1 covered stents) implanted in supraaortic arteries. The success rate of overall intervention, fenestration, and implantation of BMS was recorded. The therapeutic effects and complications during admission and follow-up (median 29.7 months, range 18-45 months) were the primary outcomes. The technical success rate was 90.3% (28/31). All thoracic lesions were totally excluded. Major complications (6.5%) were one dissection in the left subclavian artery (n = 1) and thrombus formation (n = 1). Minor complications (12.9%) were hematoma (n = 1), and type III endoleak (n = 3). During follow-up, no endoleak developed and all fenestrated branch arteries were patent, except for one left subclavian artery dissection and occlusion. Use of balloon-expandable BMS in ISF is safe and effective in reconstruction of supraarotic arteries during TEVAR.

Covered stents versus Bare-metal stents in chronic atherosclerotic Gastrointestinal Ischemia (CoBaGI): study protocol for a randomized controlled trial

BackgroundChronic mesenteric ischemia (CMI) is the result of insufficient blood supply to the gastrointestinal tract and is caused by atherosclerotic stenosis of one or more mesenteric arteries in > 90% of cases. Revascularization therapy is indicated in patients with a diagnosis of atherosclerotic CMI to relieve symptoms and to prevent acute-on-chronic mesenteric ischemia, which is associated with high morbidity and mortality. Endovascular therapy has rapidly evolved and has replaced surgery as the first choice of treatment in CMI. Bare-metal stents (BMS) are standard care currently, although retrospective studies suggested significantly higher patency rates for covered stents (CS). The Covered stents versus Bare-metal stents in chronic atherosclerotic Gastrointestinal Ischemia (CoBaGI) trial is designed to prospectively assess the patency of CS versus BMS in patients with atherosclerotic CMI.Methods/designThe CoBaGI trial is a randomized controlled, parallel-group, patient- and investigator-blinded, superiority, multicenter trial conducted in six centers of the Dutch Mesenteric Ischemia Study group (DMIS). Eighty-four patients with a consensus diagnosis of atherosclerotic CMI are 1:1 randomized to either a balloon-expandable BMS (Palmaz Blue with rapid-exchange delivery system, Cordis Corporation, Bridgewater, NJ, USA) or a balloon-expandable CS (Advanta V12 over-the-wire, Atrium Maquet Getinge Group, Hudson, NH, USA). The primary endpoint is the primary stent-patency rate at 24 months assessed with CT angiography. Secondary endpoints are primary stent patency at 6 and 12 months and secondary patency rates, freedom from restenosis, freedom from symptom recurrence, freedom from re-intervention, quality of life according the EQ-5D-5 L and SF-36 and cost-effectiveness at 6, 12 and 24 months.DiscussionThe CoBaGI trial is designed to assess the patency rates of CS versus BMS in patients treated for CMI caused by atherosclerotic mesenteric stenosis. Furthermore, the CoBaGI trial should provide insights in the quality of life of these patients before and after stenting and its cost-effectiveness. The CoBaGI trial is the first randomized controlled trial performed in CMI caused by atherosclerotic mesenteric artery stenosis.Trial registrationClinicalTrials.gov, ID: NCT02428582. Registered on 29 April 2015.

Long-Term Risk of In-Stent Restenosis and Stent Fracture for Extracranial Vertebral Artery Stenting.

Stenting and angioplasty of the vertebral artery (VA) is used to treat symptomatic stenosis but the long-term outcomes and complications are unclear. This study evaluated the long-term clinical outcomes and procedure-related complications in patients who underwent extracranial VA stenting and angioplasty, in particular the risks of in-stent restenosis (ISR) and stent fracture. This was aretrospective review of consecutive patients suffering from symptomatic extracranial VA stenosis who were treated with balloon-expandable bare metal stents. The clinical and angiographical outcomes were reviewed for procedural complications, recurrent stroke, ISR and stent fracture. In this study 22patients (17male, 5female) with amean age of 63.4years (SD9.1years) were included. The median follow-up was 56months (interquartile range IQR 51.8months). There were no periprocedural complications. The cumulative ISR risk was 45% with 6cases detected at 1year and 3cases detected at 3years post operation. The cumulative stent fracture rate at 1year, 3years, 5years and the entire follow-up period were 5%, 15%, 25%, and 30%, respectively. Posterior circulation stroke occurred in 1patient (4.5%), and 3patients died of non-cerebrovascular causes during follow-up. Of the patients 2 with ISR and stent fracture required additional treatment. The long-term ISR and stent fracture risks were high in extracranial VA stenosis treated with balloon-expandable bare metal stents. The risk of stent fracture increased over time during the follow-up period. Further studies should be conducted to clarify the long-term safety and efficacy of extracranial VA stenting.

Adjustable diameter TIPS in the pediatric patient: the constrained technique.

Placement of transjugular intrahepatic portosystemic shunt (TIPS) is necessary in children with portal hypertension complicated by variceal bleeding or ascites. However, placement of adult-sized endografts may be problematic due to the smaller anatomy of pediatric patients. On the other hand, placement of fixed diameter smaller stents have the corresponding problem of not accommodating future growth of the child. We describe a novel method to create an adjustable diameter TIPS as a technical solution to these problems. In this technique, a balloon expandable bare metal stent is placed concentrically around the ePTFE TIPS endograft, creating an intentional narrowing in the shunt diameter than can be expanded with balloon dilation at future procedures as needed. This allows for optimal calibration of shunt hemodynamics according to the child's growth and prevents the potential need for placement of additional shunts or technically challenging TIPS reduction procedures.

In-situ investigation of stress conditions during expansion of bare metal stents and PLLA-coated stents using the XRD sin2 ψ-technique

Drug eluting stents (DES) consist of platform, coating and drug. The platform often is a balloon-expandable bare metal stent made of the CoCr alloy L-605 or stainless steel 316L. The function of the coating, typically a permanent polymer, is to hold and release the drug, which should improve therapeutic outcome. Before implantation, DES are compressed (crimped) to allow implantation in the human body. During implantation, DES are expanded by balloon inflation. Crimping, as well as expansion, causes high stresses and high strains locally in the DES struts, as well as in the polymer coating. These stresses and strains are important design criteria of DES. Usually, they are calculated numerically by finite element analysis (FEA), but experimental results for validation are hardly available.In this work, the X-ray diffraction (XRD) sin2ψ-technique is applied to in-situ determination of stress conditions of bare metal L-605 stents, and Poly-(L-lactide) (PLLA) coated stents. This provides a realistic characterization of the near-surface stress state and a validation option of the numerical FEA.XRD-results from terminal stent struts of the bare metal stent show an increasing compressive load stress in tangential direction with increasing stent expansion. These findings correlate with numerical FEA results. The PLLA-coating also bears increasing compressive load stress during expansion.

Outcomes of covered versus bare-metal balloon-expandable stents for aortoiliac occlusive disease

Randomized trials and retrospective data suggest that covered balloon-expandable (CBE) stents have better short-term patency compared with balloon-expandable bare-metal stents (BMSs) in the treatment of iliac artery disease. This study evaluated midterm outcomes of BMSs vs CBE stents placed in the common iliac artery (CIA) for aortoiliac occlusive disease. All endovascular interventions for symptomatic peripheral arterial occlusive disease performed at a single institution from 2006 to 2012 were reviewed. Patients undergoing stent placement in the CIA segment were included in the analysis. Demographic data, TransAtlantic Inter-Society Consensus (TASC) classification, stent type, patency, and limb reinterventions were compared. For treatment of de novo distal aorta or CIA stenosis, 254 procedures were performed in 162 patients. BMSs were used in 190 arteries; CBE stents were used in 64 arteries. There was no difference in age, gender, or TASC classification between the two groups. Mean follow-up was 22 ± 16 months. Primary patency, assisted patency, and secondary patency were significantly better in the BMS group. CIAs treated with covered stents were more likely at 1 year or longer to require repeated intervention (hazard ratio, 2.5; 95% confidence interval, 1.2-5.3; P = .009). TASC classification did not predict need for reintervention in either group. Multivariate analysis revealed dual antiplatelet therapy to be the only other factor to affect patency during long-term follow-up. In this study, BMSs had significantly better patency compared with CBE stents for treatment of aortoiliac occlusive disease. A randomized trial comparing patency as well as restenosis rates with long-term follow-up is needed to determine if there is any benefit from use of covered stents in the aortoiliac segment.

Safety and efficacy of different stent types for the endovascular therapy of extracranial vertebral artery disease

This study aims to determine safety and efficacy of different stent types for extracranial vertebral artery stenting (EVAS) at a single-center institution. Although endovascular revascularization techniques are well established for a variety of arterial vessel territories, its role within the vertebrobasilar system is less well defined. We retrospectively analyzed all EVAS procedures performed at our institution between 1997 and 2012. A total of 35 EVAS procedures were attempted in 35 patients with symptomatic occlusive extracranial vertebral artery (EVA) disease. Carotid self-expanding bare-metal stents (BMS-SE; n = 18), coronary balloon-expandable bare-metal stents (BMS-BE; n = 7) or drug-eluting stents (DES-BE; n = 16) were used according to physician's choice. The overall technical and clinical success rate was 100 and 94 %, respectively. Periprocedural complications included one death 14 days after intervention due to complications of initial stroke and 3 (9 %) patients with access site complications. Follow-up after a median of 18 ± 21 months yielded an overall in-stent restenosis rate of 23 % and a recurring clinical symptoms rate of 20 % whereas both endpoints were closely associated as 83 % of patients with recurring symptoms showed significant restenosis. Concerning the stent type, BMS-SE were associated with a significant higher in-stent restenosis rate compared to balloon-expandable stents (p = 0.012), and although not statistically significant, there was a clear trend towards a lower in-stent restenosis rate in drug-eluting compared to bare-metal stents (p = 0.068). In patients with symptomatic extracranial vertebral artery disease, stenting is a safe and effective treatment option whereas balloon-expandable stents, and particularly drug-eluting stents, are superior to self-expanding stents.

Stent outcomes for infrapopliteal arterial occlusive disease

This study aimed to determine if the different stent types used in the treatment of infrapopliteal arterial occlusive disease provide any significant advantage over one another at 6 and 12-month follow-up. Consecutive patients undergoing stenting of infrapopliteal lesions were enrolled into a non-randomised prospective registry and followed-up for 1 year. Outcome measures included binary restenosis, target lesion revascularisation, major amputation, and change in Rutherford-Becker score and ankle-brachial index (ABI).Thirty-three patients were enrolled including four patients with bilateral disease. There were 20 target vessels in the drug-eluting stent (DES) group, 13 target vessels in the balloon-expandable bare metal stent (BE-BMS) group and 14 target vessels in the self expandableb are metal stent (SE-BMS) group. Most of the patients in the study were octogenarians except in the SE-BMS group where the mean age was 73 ± 9 years. At 12 months, seven patients had died (DES = 6, BE-BMS = 1) from cardiac and cancer-related diseases. In-stent and peri-stent binary restenosis were non-statistically different between all three groups. There was a nonstatistically significant trend towards higher target vessel revascularisation in the BE-BMS group. Survival curves in all stent types demonstrated restenosis to occur within the first 6 months post-procedure. There was no significant difference in the change in Rutherford-Becker score or ABI between the groups. No major limb amputations occurred during the 12-month period. In conclusion,we did not detect a significant difference in stent performance between the different stent types used to treat infrapopliteal arterial occlusive disease. The choice of stent did not seem to affect patient survival or major amputation-free survival at 1-year follow-up.

Educational Exhibit Abstract No. 354 - Primary placement of a constrained transjugular intrahepatic portosystemic shunt: how we do it

Learning Objectives Three methods for placement of a primary constrained transjugular intrahepatic portosystemic shunt (TIPS) will be reviewed. Background TIPS creation is often complicated by hepatic encephalopathy. Medical management fails in approximately 5-10% of cases. In those patients, TIPS revision may be required by creating a flow-limiting stent using a variety of methods. To avoid the complication of hepatic encephalopathy, however, we occasionally place primary constrained stents during the initial TIPS creation, particularly if the indication for TIPS is refractory ascites. Clinical Findings/Procedure Details We take one of three approaches to creating a primary constrained TIPS. In one approach, a self-expanding 10 mm Gore-Viatorr stent graft is deployed and a 5-0 Prolene suture is tied around the midpoint. The modified graft is then crimped into a peel-away sheath and re-sterilized. After formation of the intrahepatic tract, the graft is deployed and balloon dilated. The suture creates a flow-limiting constriction which may be dilated and/or broken as needed to improve flow. Prolene is favored due to its high elasticity, which allows for balloon expansion. Another approach involves deploying the stent graft through a balloon-expandable bare metal stent. After accessing the portal vein, we place a short 6-8 mm bare metal stent within the intrahepatic tract. Once this stent is in place, the Viatorr stent graft is deployed within it and the entire assembly is dilated to the diameter needed. The outer stent maintains a constriction in the inner stent graft due to its higher radial force, and can be dilated at a later time. In the third technique, a balloon-mounted Atrium iCast stent graft is placed on a 10-French sheath and a 4-0 absorbable suture is tied around its midpoint. This stent is then crimped onto a balloon and deployed, with the suture serving as the constriction point. Dilation can be done at a future time if needed. Conclusion and/or Teaching Points Creation of a primary constrained TIPS can be readily performed, enabling a degree of control over reduction of the portosystemic gradient both at initial TIPS creation and at follow up. Whether these techniques result in a reduction of hepatic encephalopathy requires further investigation.

Intravascular ultrasound analysis of small vessel lesions treated with the sparrow coronary stent system: Results of the CARE II trial

The aim of this study was to evaluate the Sparrow sirolimus-eluting stent (Sparrow-SES) against the Sparrow bare-metal stent (Sparrow-BMS) and conventional balloon-expandable bare-metal stent (BMS: Driver/Micro-Driver stent, Medtronic Vascular, Santa Rosa, CA). The Sparrow stent (Biosensors International, Singapore) consists of a guide wire-based, self-expandable, ultra-thin nitinol stent. The performance of this device with sirolimus in a fully biodegradable polymer has not been determined. A total of 74 patients were included in this intravascular ultrasound (IVUS) sub-study of the CARE II trial, which was a prospective, randomized, multicenter trial in the treatment of single de novo native coronary artery lesions in vessels ranging from 2.0 mm to 2.75 mm in diameter (Sparrow-SES: n = 31, Sparrow-BMS: n = 22, BMS: n = 21). Stent volume index (VI) was significantly increased 8-month later in Sparrow-SES and Sparrow-BMS, but not in BMS (4.0 ± 1.0 to 4.6 ± 1.0 mm(3) /mm, p<0.0001, 4.0 ± 0.6 to 4.4 ± 0.8 mm(3) /mm, p<0.05, and 5.2 ± 1.0 to 5.1 ± 0.9 mm(3) /mm, p=0.421, respectively). % neointimal obstruction in Sparrow-SES was significantly smaller than those in Sparrow-BMS and BMS at follow-up (17.6 ± 9.4 vs. 36.2 ± 13.8 and 39.9 ± 11.1%, p<0.001). Sparrow-SES showed a mean 15% stent expansion and good suppression of neointimal proliferation, resulting in a significantly lower percentage of change in lumen VI during follow-up period (Sparrow-SES: -6.2 ± 16.2%, Sparrow-BMS: -30.4 ± 11.6%, BMS: -40.4 ± 10.0%, p<0.001). The self-expanding Sparrow-SES demonstrated chronic stent expansion, good suppression of neointimal proliferation and resulted in a more preserved lumen in stented small vessels compared with the Sparrow-BMS and conventional balloon expandable BMS.

The biocompatibility of rapidly degrading polymeric stents in porcine carotid arteries

The goal of this study was to evaluate the biocompatibility of materials for use in fully bioabsorbable vascular stents. 10:90 poly( l-lactic-co-glycolic acid) (10:90 l-PLGA), 85:15 poly( l-lactic-co-glycolic acid) (85:15 l-PLGA), polydioxanone (PDO), and poly- l-lactic acid ( l-PLA) polymers were chosen as materials. Polymeric fibers were woven into a braided structure with a mass equivalent to or greater than that expected for a vascular stent, secured to balloon-expandable bare metal stents and implanted into porcine carotid arteries. The in vivo response was analyzed at 30 and 90 days by angiography, histopathology, and histomorphometry. All vessels were patent at 30 and 90 days. Injury score and neointima formation was mild for all samples. The faster-degrading 10:90 l-PLGA had the highest inflammatory response at 30 days, but was completely absorbed with minimal inflammation and neointimal formation at 90 days. PDO showed signs of partial absorption at 90 days, while 85:15 l-PLGA and l-PLA demonstrated minimal absorption at 30 and 90 days. The inflammatory response to these three groups was similar over the experimental period. Using a robust materials-testing platform, we demonstrated long-term patency and intravascular biocompatibility of bioabsorbable polymers with varying rates of resorption. The data point to biocompatibility of a polymeric stent in the vascular space that is fully absorbable in less than a year.

Infragenicular Stent Implantation for Below-the-Knee Atherosclerotic Disease: Clinical Evidence From an International Collaborative Meta-Analysis on 640 Patients

To report a systematic review of the literature published on the outcomes of stenting for below-the-knee disease in patients with critical limb ischemia (CLI). Potentially relevant studies of stent implantation in the infragenicular arteries in >or=5 patients with >or=1-month follow-up were systematically sought in BioMedCentral, ClinicalTrials.gov, The Cochrane Collaboration Register of Controlled Trials (CENTRAL), Google Scholar, and PubMed. Data were abstracted and pooled with a random-effect model to generate risk estimates with 95% confidence intervals (CI). Interaction tests were performed to compare different stent types. A risk of bias assessment was conducted separately, as were appraisals for small study bias, statistical heterogeneity, and inconsistency. Eighteen nonrandomized studies were retrieved comprising 640 patients. After a median follow-up of 12 months, binary in-stent restenosis occurred in 25.7% (95% CI 11.6% to 40.0%), primary patency in 78.9% (95% CI 71.8% to 86.0%), improvement in Rutherford class in 91.3% (95% CI 85.5% to 97.1%), target vessel revascularization in 10.1% (95% CI 6.2% to 13.9%), and limb salvage in 96.4% (95% CI 94.7% to 98.1%). Head-to-head comparisons showed that sirolimus-eluting stents were superior to balloon-expandable bare metal stents in preventing restenosis and increasing primary patency (both p<0.001); sirolimus-eluting stents were also better than paclitaxel-eluting stents in terms of primary patency (p<0.001) and repeat revascularizations (p = 0.014). Percutaneous infragenicular stent implantation after failed or unsuccessful balloon angioplasty is associated with favorable clinical results in patients with CLI. Notwithstanding limitations of primary studies, sirolimus-eluting stents appear superior to bare metal and paclitaxel-eluting stents in terms of angiographic and/or clinical outcomes.

Prospective randomized trial comparing a nitinol self-expanding coronary stent with low-pressure dilatation and a high-pressure balloon expandable bare metal stent

The recent SCORES trial demonstrated that lower dilatation pressures seen with self-expanding (SE) stents may be associated with lower rates of target lesion revascularization (TLR). To determine whether SE stents with low-pressure dilatation are as safe and effective as balloon expandable (BE) stents. We randomly assigned 254 patients with 279 coronary lesions to groups receiving either SE with low-pressure dilatation <12 atm (n = 143) or conventional BE stents (n = 136). Thereafter, acute results and long-term outcomes were compared. Baseline patient and angiographic characteristics were similar in two groups. The incidence of procedural complications, such as slow flow, side branch occlusion, and edge dissection were significantly lower in the SE group than in the BE group (overall: SE, 17; BE, 35; P < 0.01), and the occurrence of myocardial infarction tended to be lower in SE than in BE (SE, 1; BE, 4; not significant). Although acute gain was significantly smaller with SE than BE (SE, 2.21 +/- 0.65 mm; BE, 2.42 +/- 0.62; P < 0.01), probably due to gradual expansion of the SE stent, nearly identical minimum luminal diameters on follow-up angiography (SE, 2.14 +/- 0.92 mm vs. BE, 2.22 +/- 0.93; not significant) and similar angiographic restenosis (SE, 18.1% vs. BE, 20.5%). and TLR rates (SE, 16.1% vs. BE, 14.0%) were apparent. This prospective randomized trial demonstrates that SE stents with low-pressure dilatation is safe and effective strategy for treating coronary arterial stenosis.