Balloon-expandable Stent Research Articles

Flexible endoscopy for pediatric tracheobronchial metallic stent placement, maintenance and long-term outcomes.

ObjectivesTo assess the placement, surveillance management and long-term outcomes of the tracheobronchial (TB) balloon expandable metallic stent (BEMS) managed by therapeutic flexible endoscopy (TFE).MethodsThis is a retrospective review and analysis of all computerized medical records and related flexible endoscopy videos of pediatric patients who received TB BEMS during 20 years period, from January 1997 to December 2016. TFE techniques with forceps debridement, balloon dilatation and laser ablation were used to implant stents, perform regular surveillance, maintain their functions, and expand the diameters of BEMS. Short-length (30cm-36cm) endoscopes of OD 3.2mm to 5.0mm coupled with the noninvasive ventilation, without ventilation bag, mask or airway tube, supported the whole procedures.Results146 BEMS were implanted in 87 consecutive children, including 84 tracheal, 15 carinal and 47 bronchial stents. At the time of placement, the mean age was 35.6 ± 54.6 month-old (range 0.3–228) and the mean body weight was 13.9 ± 10.6 kg (range 2.2–60). Surveillance period was 9.4 ± 6.7 years (range, 0.3–18.0). Satisfactory clinical improvements were noted immediately in all but two patients. Seventy-two (82.8%) patients were still alive with stable respiratory status, except two patients necessitating TFE management every two months. Fifty-one stents, including 35 tracheal and 16 bronchial ones, were successfully retrieved mainly with rigid endoscopy. Implanted stents could be significantly (< .001) further expanded for growing TB lumens. The final stent diameters were positively correlated to the implanted duration. Altogether, 33 stents expired (15 patients), 51 were retrieved (40 patients), and 62 remained and functioning well (38 patients), with their mean duration of 7.4 ± 9.5, 34.9 ± 36.3 and 82.3 ± 62.5 months, respectively.ConclusionIn pediatric patients, TFE with short-length scopes coupled with this NIV support has provided a safe, feasible and effective modality in placing and subsequently managing TB BEMS with acceptable long-term outcomes.

Abstract WMP40: A Comparison of Three Different Endovascular Approaches for Extracranial Internal Carotid Artery Lesions in the Setting of Tandem Occlusions

Background: Endovascular treatment (EVT) of extracranial internal carotid artery (ICA) lesions in the setting of tandem occlusions is a challenge, being angioplasty alone (AA) or angioplasty+stenting (AS) the two current approaches. Hemorrhagic transformation (HT) is a major problem when a conventional [self-expanding (SX)] stent is placed, regarding the need of early double antiplatelet therapy. Interestingly, balloon-expanding (BX) stents, due to their less thrombogenicity, may constitute an alternative, so they do not need early antiplatelets. We aimed to study differences in ICA restenosis, HT, clinical outcome and stroke recurrence between patients treated with AA or AS. Methods: Prospective study of consecutive patients with non-cardioembolic ischemic stroke and tandem occlusions, who underwent &lt;6hours EVT from April 2013 to April 2017. We compared rate of ICA high-degree stenosis/occlusion at 24h, HT, clinical outcome (change in NIHSS at 24h and at discharge over NIHSS at admission, and mRS≥2 at 3 months) and stroke recurrence within 3 months between AA and AS (SX and BX stents) groups. Results: Ninety-two patients fulfilled inclusion criteria: mean age 64.6±12.6 years. Forty (43.5%) received AA and 52 (56.5%) AS (61.5% SX stents, 38.5% BX stents). Both groups were comparable in baseline characteristics. Fifty (54.3%) received IV rtPA. Patients who underwent AA presented ICA high-degree stenosis/occlusion at 24h more frequently than those who underwent AS (86.5% vs. 21.2%, p &lt;0.001). No differences were found in HT, clinical outcome and stroke recurrence ( p &gt;0.05 for all comparisons). In the AS group, all SX stents received antiplatelets after EVT, whereas in 75% of cases in the BX group no antiplatelets were started within 24h. However, no differences were found in ICA high-degree stenosis /occlusion at 24h, clinical outcome and stroke recurrence ( p &gt;0.05). We neither found differences in HT. Nevertheless, all cases were asymptomatic in the BX stents group. Conclusions: Emergent ICA stenting seems to have a lower risk of restenosis compared to AA, without a significant increase of HT and stroke recurrence or a worse clinical outcome. BX stents, without early antiplatelet therapy, are a promising alternative to conventional carotid stents.

Abstract WP118: Incidence and Management of Re-stenosis in Patients Stented for Intracranial Atherosclerotic Disease: A Consecutive Series of 226 Patients

Introduction: Angioplasty and stenting for intracranial atherosclerotic disease can re-establish adequate luminal diameter in highly stenotic arteries and improve cerebral blood flow. As in other vascular territories, intracranial stented arteries may develop delayed re-stenosis due to progression of atherosclerotic disease or endothelial hyperplasia. The primary strategies for management of re-stenosis have included aggressive medical therapy, angioplasty only, and repeat angioplasty and stenting. Materials and Methods: A total of 226 patients underwent intracranial angioplasty and stenting for symptomatic ICAD from 2000-2017. Patients were treated with balloon expandable coronary stents until 2002, when self-expanding intracranial nitinol stents became available. The series included: 21 balloon expandable coronary stents, 33 Neuroform stents, 37 Enterprise stents, and 135 Wingspan stents. Of this group, 210 patients had delayed follow up intracranial vascular imaging at 6 months, 1 year, and longer. In follow up, 24 of the 210 patients (11.4 %) developed significant re-stenosis, defined as 70% or greater. Eleven of the patients were symptomatic and 13 had no symptoms. A total of 17 patients underwent endovascular treatment of their re-stenosis, and 7 had medical management only. Results: The mean time interval for re-stenosis was 8.7 months. Of the 17 patients treated with endovascular therapy for re-stenosis, 4 patients had angioplasty only and 13 patients had angioplasty and stenting. There was one peri-procedural stroke in this group (5.9%) and no other strokes in the follow up period (mean 2.4 years, range 6 months - 7 years). Of the 7 patients who were managed medically, 1 patient had a stroke (14.3%) in the follow up period at 10 months (mean follow up 2.1 years, range 3 months - 5 years). Discussion: The preliminary data from this study suggests that patients with severe re-stenosis may be at significant risk of stroke, even if the re-stenosis is currently asymptomatic. As with other vascular territories, re-stenosis can be managed with multiple modalities, but repeat angioplasty and stenting in this series appears to be a low risk and viable option for these patients compared with medical therapy alone.

Preliminary Outcomes of the LifeStream Balloon-Expandable Covered Stent in Fenestrated and Branched Thoracoabdominal Endovascular Repairs

Purpose: To evaluate the 1-year outcomes of thoracoabdominal aortic aneurysm (TAAA) repair using fenestrated and branched stent-grafts and a novel balloon-expandable covered stent. Methods: Between March 2015 and January 2017, 18 patients (median age 74.7 years; 14 men) received 43 LifeStream balloon-expandable covered stents in conjunction with Zenith fenestrated/branched stent-grafts to bridge 11 celiac trunks, 8 superior mesenteric arteries, and 24 renal arteries (total 32 fenestrations and 11 branches). Results: Stent delivery and deployment was successful in all cases. At 30 days, 5 patients presented with perifenestration endoleaks (type IIIc) secondary to inadequate sealing of the LifeStream covered stent in 7 (22%) of 32 fenestrations. No type IIIc endoleaks were reported in the branched cases. Four patients had a secondary endovascular reintervention with proximal relining by means of a bare balloon-expandable stent at the perifenestration transition area, with complete resolution of the endoleak at 1-year follow-up. One patient refused reintervention. The last 4 fenestrated stent-grafts of this series had prophylactic perifenestration bare stent relining with no evidence of type IIIc endoleaks at imaging. At a median follow-up of 14.1 months (interquartile range 11, 22), the 12-month LifeStream patency rate was 100%. Conclusion: This single-center preliminary experience with the LifeStream balloon-expandable covered stent in fenestrated/branched stent-grafts for TAAA repairs demonstrated good patency; however, an unexpectedly high rate of type IIIc endoleaks was observed. These endoleaks were resolved with reintervention or during the index procedure by proximal relining with a bare balloon-expandable stent, achieving adequate perifenestration sealing.

Balloon-expandable stent angioplasty in the treatment of vertebral artery stenosis in the V2 segment.

IntroductionVertebral artery stenosis is a major cause of posterior circulation ischemia in the elderly. There is not a clear consensus on the optimal therapeutic approach for symptomatic extracranial vertebral artery stenosis.AimTo evaluate the feasibility and efficacy of balloon-expandable stent angioplasty in the treatment of vertebral artery stenosis in the V2 segment.Material and methodsFive patients with vertebral artery stenosis (V2 segment) and treatment of percutaneous transluminal stenting from July 2009 to June 2014 were retrospectively evaluated. All patients underwent color Doppler, transcranial color Doppler (TCD), CT angiography (CTA) and cerebral digital subtraction angiography (DSA) preoperatively. Whether there was osseous oppression was determined according to neck computed tomography (CT) and CTA. After the surgery, angiography was performed to determine if there was infarction or bleeding in the intracranial vertebral artery, basilar artery and posterior cerebral artery. The surgical parameters, residual stenosis, complications, etc. were recorded and evaluated. The patients were followed up accordingly.ResultsFive patients (3 males, 2 females; average age of 66 ±4.2, range of 54–75) were enrolled in the study. Balloon-expandable stents were successfully implanted in the 5 patients. The mean residual stenosis after the balloon-expandable stenting (preoperative: average, 87.0 ±6.6%, range: 75–93%) was 12.6 ±7.8% (range: 5–25%). The clinical symptoms disappeared or receded. No serious complications occurred.ConclusionsThe balloon-expandable stent angioplasty seemed to be feasible and efficacious in treating vertebral artery stenosis in the V2 segment. Further study with a large sample size is needed.

Incrementally Expandable Transjugular Intrahepatic Portosystemic Shunts: Single-Center Experience.

The purpose of this study is to investigate the long-term safety and efficacy of a small-diameter expandable transjugular intrahepatic portosystemic shunt (TIPS) in the management of portal hypertension. This single-center retrospective study included 28 patients (12 women and 16 men; mean age, 56.9 years) who underwent small-diameter expandable TIPS creation between 2008 and 2010 for refractory ascites (n = 15; mean [± SD] model for end-stage liver disease [MELD] score, 15.5 ± 5.3) or gastrointestinal variceal bleeding (n = 13; mean MELD score, 15.2 ± 8.4). An expandable TIPS was created by deploying a covered stent inside a balloon expandable stent. For patients with recurrent symptoms, TIPS adjustment was made by balloon expandable stent balloon dilation. The TIPS diameter was defined as the diameter of the final angioplasty balloon. TIPS patency and efficacy and the rate of post-TIPS hepatic encephalopathy were evaluated. The median diameter of the initial TIPS was 8 mm in the group with variceal bleeding compared with 6 mm in the group with ascites (p = 0.003). The primary patency rate at 1 and 5 years was 90.8% and 73.3%, respectively. Eighty percent of patients with ascites required no or less-frequent large-volume paracentesis. The clinical success rate for patients with acute variceal bleeding was 92.3%. Six patients with ascites (initial TIPS diameter, 6 mm) and two patients with variceal bleeding (initial diameter, 6 mm and 8 mm) required subsequent TIPS adjustment. Of the 22 patients with no prior history of enecphalophy, seven patients (31.8%) experienced new hepatic encephalopathy within 90 days. A small-diameter expandable TIPS is technically feasible and safe, with efficacy falling within the range of that of conventional TIPS. This technique offers the possibility of individualizing the degree of portal decompression.

A novel application of the culotte stent technique to bail out a jailed common iliac artery

Implanting a self-expandable stent at the ostium of the common iliac artery (CIA) may lead to coverage of the orifice of the contralateral CIA. Here, we describe a novel application of the culotte stent technique using a balloon-expandable stent to bail out an ostial stenotic legion of a jailed CIA due to prior self-expandable stent placement. The bilateral CIAs were revascularized by culotte stenting, and patency of the stents was confirmed 3 years after the procedure. The culotte stent technique was successfully applied to an ostial stenotic lesion of a jailed CIA.

Management of stenosis lesions during the period of endovascular treatment for acute ischemic stroke

Objective To investigate the management of stenosis lesions during endovascular treatment for acute ischemic stroke. Methods A total of 36 acute ischemic stroke patients combined with intracranial/extracranial arterial stenosis were treated with endovascular treatment or bridging treatment. Time from aggravation on admission or in hospital stay to femoral artery puncture, from femoral arterypuncture to recanalization were recorded. Modified Thrombolysis in Cerebral Infarction (mTICI) was usedto assess the recanalization immediately after operation. Modified Rankin Scale (mRS) was used to evaluate prognosis at 90 d after operation. Occurrence rate of symptomatic intracranial hemorrhage and mortality were recorded. Results Among 36 patients, 13 patients (36.11%) underwent intravenous thrombolysis and then endovascular thrombectomy. In all patients, there were 21 (58.33%) with intracranial stenosis and 15 (41.67%) with extracranial stenosis, 16 (44.44%) with anterior circulation stenosis and 20 (55.56%) with posterior circulation stenosis. Stent thrombectomy was used in 25 patients (69.44% ), while balloon dilatation and/or stent implantation was used in 11 patients (30.56% ). For 21 patients with intracranial arterial stenosis, 4 were treated with balloon dilatation only, 9 with Wingspan self-expandable stents and 8 with Apollo balloon-expandable stents. Fifteen patients with extracranial arterial stenosis were treated with balloon dilatation and stent implantation. A total of 33 patients (91.67%) achieved recanalization (mTICI 2b-3 grade), 21 patients (58.33% ) had good outcomes (mRS ≤ 2 score), while symptomatic intracranial hemorrhage occurred in 2 patients (5.56%) and 5 (13.89%) died. There were no statistically significant differences in the rate of good prognosis, symptomatic intracranial hemorrhage and mortality between intracranial and extracranial arterial stenosis, anterior and posterior circulation stenosis (Fisher exact probability: P > 0.05, for all). Conclusions For acute ischemic stroke patients combined with intracranial/extracranial arterial stenosis, endovascular treatment is safe and effective. DOI: 10.3969/j.issn.1672-6731.2017.11.007

Outcome of long-term complications after permanent metallic left bronchial stenting in children.

We describe the way we treated 7 children with critical long-term complications after metallic balloon-expandable stenting in the left mainstem bronchus. Endoscopic follow-up included a first bronchoscopy 3 weeks after stenting, then monthly for 3 months, every 4-6 months up to 1 year and at scheduled times to calibrate stent diameter up to final calibration. When major complications occurred, patients underwent chest computed tomographic angiography. In 1 of the 7 children (median age 2.8 years), metallic left bronchial stenting served as a bridge to surgery. After a median 4-year follow-up, all 7 children experienced recurrent stent ovalizations with stent breakage in 3 and erosion in 1. In 4 children, computed tomographic angiography showed abundant peribronchial fibrous tissue, in 2 left mediastinal rotation and in 1 displacement along the left bronchus after pulmonary re-expansion as the cause of stent-related complication. Of the 7 children, 6 underwent surgery (5 posterior aortopexy and 1 section of the ligamentum arteriosus) and 3 required nitinol stents placement within the metallic ones. One patient completed the follow-up, and 1 patient was lost to follow-up. All 5 remaining children still have permanent bronchial stents in place, patent and re-epithelialized after a median 10.5-year follow-up. There were no deaths. Satisfactory anatomical relationships when children have stents placed in the left mainstem bronchus alone do not guarantee the final success. Several mechanisms intervene to cause critical stent-related complications in children during growth. Permanent metallic stents should be used carefully, and only in selected patients.

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.

Biodegradable Magnesium Stent Treatment of Saccular Aneurysms in a Rat Model - Introduction of the Surgical Technique

The steady progess in the armamentarium of techniques available for endovascular treatment of intracranial aneurysms requires affordable and reproducable experimental animal models to test novel embolization materials such as stents and flow diverters. The aim of the present project was to design a safe, fast, and standardized surgical technique for stent assisted embolization of saccular aneurysms in a rat animal model. Saccular aneurysms were created from an arterial graft from the descending aorta.The aneurysms were microsurgically transplanted through end-to-side anastomosis to the infrarenal abdominal aorta of a syngenic male Wistar rat weighing >500 g. Following aneurysm anastomosis, aneurysm embolization was performed using balloon expandable magnesium stents (2.5 mm x 6 mm). The stent system was retrograde introduced from the lower abdominal aorta using a modified Seldinger technique. Following a pilot series of 6 animals, a total of 67 rats were operated according to established standard operating procedures. Mean surgery time, mean anastomosis time, and mean suturing time of the artery puncture site were 167 ± 22 min, 26 ± 6 min and 11 ± 5 min, respectively. The mortality rate was 6% (n=4). The morbidity rate was 7.5% (n=5), and in-stent thrombosis was found in 4 cases (n=2 early, n=2 late in stent thrombosis). The results demonstrate the feasibility of standardized stent occlusion of saccular sidewall aneurysms in rats - with low rates of morbidity and mortality. This stent embolization procedure combines the opportunity to study novel concepts of stent or flow diverter based devices as well as the molecular aspects of healing.

Biodegradable Magnesium Stent Treatment of Saccular Aneurysms in a Rat Model - Introduction of the Surgical Technique.

The steady progess in the armamentarium of techniques available for endovascular treatment of intracranial aneurysms requires affordable and reproducable experimental animal models to test novel embolization materials such as stents and flow diverters. The aim of the present project was to design a safe, fast, and standardized surgical technique for stent assisted embolization of saccular aneurysms in a rat animal model. Saccular aneurysms were created from an arterial graft from the descending aorta.The aneurysms were microsurgically transplanted through end-to-side anastomosis to the infrarenal abdominal aorta of a syngenic male Wistar rat weighing >500 g. Following aneurysm anastomosis, aneurysm embolization was performed using balloon expandable magnesium stents (2.5 mm x 6 mm). The stent system was retrograde introduced from the lower abdominal aorta using a modified Seldinger technique. Following a pilot series of 6 animals, a total of 67 rats were operated according to established standard operating procedures. Mean surgery time, mean anastomosis time, and mean suturing time of the artery puncture site were 167 ± 22 min, 26 ± 6 min and 11 ± 5 min, respectively. The mortality rate was 6% (n=4). The morbidity rate was 7.5% (n=5), and in-stent thrombosis was found in 4 cases (n=2 early, n=2 late in stent thrombosis). The results demonstrate the feasibility of standardized stent occlusion of saccular sidewall aneurysms in rats - with low rates of morbidity and mortality. This stent embolization procedure combines the opportunity to study novel concepts of stent or flow diverter based devices as well as the molecular aspects of healing.

Self-Expanding Versus Balloon-Expandable Stents for Iliac Artery Occlusive Disease: The Randomized ICE Trial

ObjectivesAtherosclerosis of iliac arteries is widespread. As inflow vessels, they are of great clinical significance and increasingly being treated by endovascular means. Most commonly, stents are implanted. BackgroundSo far, due to a lack of comparative data, no guideline recommendations on the preferable stent type, balloon-expandable stent (BE) or self-expanding stent (SE), have been issued. MethodsIn this randomized, multicenter study, patients with moderate to severe claudication from common or external iliac artery occlusive disease were assigned 1:1 to either BE or SE. The primary endpoint was binary restenosis at 12 months as determined by duplex ultrasound. Key secondary endpoints were walking impairment, freedom from target lesion revascularization (TLR), hemodynamic success, target limb amputation, and all-cause death. ResultsSix hundred sixty patients with 660 lesions were enrolled at 18 German and Swiss sites over a period of 34 months; 24.8% of the patients had diabetes and 57.4% were current smokers. The common iliac artery was affected in 58.9%. One hundred nine (16.5%) lesions were totally occluded and 25.6% heavily calcified. Twelve-month incidence of restenosis was 6.1% after SE implantation and 14.9% after BE implantation (p = 0.006). Kaplan-Meier estimate of freedom from TLR was 97.2% and 93.6%, respectively (p = 0.042). There was no between-group difference in walking impairment, hemodynamic success, amputation rate, all-cause death, or periprocedural complications. ConclusionsThe treatment of iliac artery occlusive disease with SE as compared with BE resulted in a lower 12-month restenosis rate and a significantly reduced TLR rate. No safety concerns arose in both groups. (Iliac, Common and External [ICE] Artery Stent Trial; NCT01305174)

Clinical Impact of Intravascular Ultrasound Guidance During Endovascular Treatment of Subclavian Artery Disease

Purpose: To evaluate the short- and long-term efficacy of intravascular ultrasound (IVUS) guidance during endovascular treatment (EVT) of subclavian artery disease. Methods: The multicenter SCALLOP registry (SubClavian Artery disease treated with endovascuLar therapy; muLticenter retrOsPective registry) was interrogated to identify 542 patients who underwent successful EVT for SCAD between January 2003 and December 2012. Lesions were classified according to the use of IVUS guidance: 177 patients (mean age 68.9±8.6 years; 149 men) with and 373 patients (mean age 69.9±8.7 years; 275 men) without. The main outcome was the difference in primary patency; secondary outcomes were differences in assisted primary patency, secondary patency, overall survival, freedom from major adverse cardiovascular events [MACE; all-cause mortality, myocardial infarction (MI), and stroke], and freedom from major adverse events (MAE). Multivariate analysis of the IVUS+ group was performed to identify predictors of failure; results are presented as the hazard ratio (HR) and 95% confidence interval (CI). Results: In total, 538 (97.8%) lesions were treated with stents and 12 lesions by balloon angioplasty alone. Periprocedural and in-hospital overall complication rates did not differ significantly between IVUS+ (10.2%) and IVUS– (8.8%, p=0.617). Long-term follow-up demonstrated no significant difference between IVUS+ and IVUS– groups in 5-year all-cause mortality (p=0.37), MI (p=0.07), stroke (p=0.31), or MACE (p=0.07). However, 5-year primary patency was significantly higher in the IVUS+ group (88.5% vs 77.7%, p=0.03). There were no group differences in 5-year assisted primary patency (90.4% vs 89.9%, p=0.81) or secondary patency (99.4% vs 97.1%, p=0.25). Multivariate analysis of the IVUS+ group identified in-hospital stroke (HR 16.92, 95% CI 3.60 to 79.42, p<0.01) and combined use of balloon-expandable and self-expanding stents (HR 5.59, 95% CI 1.22 to 25.65, p=0.02) as independent negative predictors of primary patency. Conclusion: These results suggest that IVUS guidance can significantly improve long-term primary patency following endovascular treatment of subclavian artery disease.

Midterm to long-term safety and efficacy of self-expandable nitinol stent implantation for coarctation of aorta in adults.

Endovascular treatment of coarctation of aorta (CoA) by self-expandable Nitinol stents is one of the recognized treatment methods and may be an alternative to surgery or balloon-expandable stent implantation for CoA but there is little information about midterm to long term results of self-expandable stents. Sixty-two patients with CoA (40 men), with a mean age of 30.7 ± 11 years, (range 17-63 years) underwent stent implantation with Optimed self-expandable Nitinol stents between 2005 and 2014. Successful outcome was defined as peak systolic pressure gradient ≤20 mmHg after stent implantation. The patients were followed-up clinically and by echocardiography and in patients, in whom there was suspicion of recoarctation, CT angiography or recatheterization was performed. 65 stents were successfully implanted in all 62 patients. Peak systolic pressure gradient decreased from mean 62.4 ± 18 mmHg (range 35-100 mmHg) to mean 2.8 ± 5 mmHg (range 0-15 mmHg; P < 0.001). Stent displacement occurred in 3 patients during the procedure. These were managed successfully by an overlapping second stent. None of the patients had major complications such as aortic dissection, rupture, or vascular access problems. In follow up, only three patients had recoarctation, and two of these were managed successfully by balloon redilation or further stenting 16 and 18 months after the first procedure and one patient refused reintervention. There were two deaths, unrelated to the procedure, 12 and 78 months after the initial intervention. Follow-up of a mean of 45.5 ± 17 months (range 12-105 months) demonstrated no evidence of aneurysm formation or stent fracture. Self-expandable nitinol stents for the treatment of native and recurrent CoA is safe and has good efficacy with acceptable midterm to long-term outcome.

Late outcomes after interventional treatment – Successful stenting of Takayasu arteritis lesions. Single center experience in Bulgaria

AimThe studied group included patients at different age and gender with follow-up period at least 1 year. The work represents endovascular treatment of patients with different localization of the disease and according to the target lesion proper endovascular access was selected. Methods and resultsThe patients are divided into groups, depending on the Numano classification. Seven of studied patients were in age between 33 and 44 years, only 1 was 65 years old, 7 of them were females and 1 male. The patients were accumulated for the period of 1 year.Doppler sonography was used for screening of the patients with known Takayasu disease. Treated lesions were as follows: left subclavian artery – 3 patients, right subclavian artery – 1 patient, right common carotid artery – 1 patient, brachiocephalic trunk – 1 patient, superior mesenteric artery – 2 patients, both external iliac arteries – 1 patient, LAD – 1 patient. Endovascular access of choice were right femoral, right radial, left radial, and right brachial. The used devices were balloon-expandable stents, self-expandable stents, DES/coronary/, PTA only – DCB. ConclusionsAll Takayasu patients in our report were successfully treated with implantation of different types of stents. One year results showed no significant restenosis, except in 1 patient with early restenosis until 6th month.

Complications after endovascular treatment of hepatic artery stenosis after liver transplantation

BackgroundHepatic artery stenosis (HAS) after liver transplantation can progress to hepatic artery thrombosis (HAT) and a subsequent 30% to 50% risk of graft loss. Although endovascular treatment of severe HAS after liver transplantation has emerged as the dominant method of treatment, the potential risks of these interventions are poorly described. MethodsA retrospective review of all endovascular interventions for HAS after liver transplantation between August 2009 and March 2016 was performed at a single institution, which has the largest volume of liver transplants in the United States. Severe HAS was identified by routine surveillance duplex ultrasound imaging (peak systolic velocity >400 cm/s, resistive index <0.5, and presence of tardus parvus waveforms). ResultsIn 1129 liver transplant recipients during the study period, 106 angiograms were performed in 79 patients (6.9%) for severe de novo or recurrent HAS. Interventions were performed in 99 of 106 cases (93.4%) with percutaneous transluminal angioplasty alone (34 of 99) or with stent placement (65 of 99). Immediate technical success was 91%. Major complications occurred in eight of 106 cases (7.5%), consisting of target vessel dissection (5 of 8) and rupture (3 of 8). Successful endovascular treatment was possible in six of the eight patients (75%). Ruptures were treated with the use of a covered coronary balloon-expandable stent graft or balloon tamponade. Dissections were treated with placement of bare-metal or drug-eluting stents. No open surgical intervention was required to manage any of these complications. With a median of follow-up of 22 months, four of eight patients (50%) with a major complication progressed to HAT compared with one of 71 patients (1.4%) undergoing a hepatic intervention without a major complication (P < .001). One patient required retransplantation. Severe vessel tortuosity was present in 75% (6 of 8) of interventions with a major complication compared with 34.6% (34 of 98) in those without (P = .05). In the complication cohort, 37.5% (3 of 8) of the patients had received a second liver transplant before intervention compared with 12.6% (9 of 71) of the patients in the noncomplication cohort (P = .097). ConclusionsAlthough endovascular treatment of HAS is safe and effective in most patients, target vessel injury is possible. Severe tortuosity of the hepatic artery and prior retransplantation were associated with a twofold to threefold increased risk of a major complication. Acute vessel injury can be managed successfully using endovascular techniques, but these patients have a significant risk of subsequent HAT and need close surveillance.

The best in vitro conditions for two and three parallel stenting during endovascular aneurysm repair

ObjectiveThe aim of this study is to identify which endograft-parallel stent combinations and which degree of oversizing result in the most adequate fit in a juxtarenal abdominal aneurysmal neck, when using a double or triple parallel-stent (chimney) technique. MethodsIn vitro silicon, juxtarenal, abdominal aortic aneurysmal neck models of different diameters, with two and three side-branches (simulating both the renal and superior mesenteric arteries), were constructed. Two different endografts of three diameters each, with two or three parallel stents (of 6 mm and 6 mm; or 6 mm, 6 mm, and 8 mm) were tested (Endurant-II endograft [Medtronic Inc, Santa Rosa, Calif] with balloon-expandable BeGraft stent [Bentley InnoMed, Hechingen, Germany] and an Excluder endograft [W. L. Gore and Associates, Flagstaff, Ariz] with self-expanding Viabahn stent [W. L. Gore and Associates]), applying three endograft-oversizing degrees: recommended (15%), excessive (30%), and over-excessive (40%). After remodeling, using the kissing-balloon technique at 37°C (98.6°F), 36 endograft-stent-oversizing models were scanned by computed tomography. The area of the gutters, parallel-stent compression, and main endograft infolding were recorded. ResultsIncreasing oversizing (15%, 30%, and 40%) revealed a nonsignificant propensity toward smaller gutters and similar parallel-stent compression, but it significantly augmented infolding, more in three parallel-stent models (0%, 0%, 67% and 0%, 33%, 83% of cases; P = .015 and .018, for two and three parallel-stent models; n = 36) and mainly for the Excluder-Viabahn combination. The Excluder-Viabahn showed significantly smaller gutters, but with higher stent compression, than Endurant-BeGraft combinations for both two and three parallel stents (8.2 mm2, 22.6 mm2; P = .002 and 14.4 mm2, 23.3 mm2; P = .009 gutter area; and 18%, 2%; P < .001 and 15%, 2%; P = .007 relative stent area compression, respectively). ConclusionsBetter endograft stent apposition was usually attained when using 30% oversizing during two and three parallel-stent techniques. Higher oversizing was related to nonsignificant smaller gutters but higher rates of infolding. Smaller gutters, but higher stent compression and risk of infolding, were achieved with the Excluder-Viabahn than with the Endurant-BeGraft combination.

Numerical analysis of crimping and inflation process of balloon-expandable coronary stent using implicit solution.

The paper presents an applied methodology for numerical finite element analysis of coronary stent crimping and the free inflation process with the use of a folded noncompliant angioplasty balloon. The use of an implicit scheme is considered as the most original part of the work, as an explicit finite element procedure is very often preferred. Hitherto, when the implicit solution was used for the finite element solution, the simulated issue was largely simplified. Therefore, the authors focused on the modelling methodology with minimum possible simplification, ie, a full load path (compression and inflation in single analysis), solid element discretization, and sophisticated contact models (bodies with highly different stiffness). The obtained results are partially compared with experimental data (radial force during the crimping procedure) and present satisfactory compliance. The authors believe that presented methodology allow for significant improvement of the obtained results, as well as potential extension of the research scope, compared to previous efforts performed using the explicit integration scheme. Moreover, the presented methodology is believed to be suitable for sensitivity and optimization studies.

Covered Balloon-Expanding Stents in Airway Stenosis.

The balloon-expanding stents are widely available but rarely described for use within the tracheobronchial tree. This report describes our experience with these stents in airway stenosis particularly as a lobar salvage therapy. This was a retrospective review of all records in which the balloon-expanding stents were used at a tertiary medical center. Ages, sex, location of stenosis, etiology of stenosis, stent size, duration of stent placement and associated interventions for airway stenosis were recorded. Patient's self-reported respiratory symptoms, dyspnea scale, and radiographic imaging at baseline and after stent placement were also reported. Twenty-one Atrium iCAST stents were inserted in 18 patients with malignant and benign airway disease. The median age was 69.5 years (interquartile range, 53.5 to 74). Most stents (n=20, 95%) were deployed in the lobar airways. There was a significant improvement in the modified Medical Research Council dyspnea scale from median of 3 to 2 (P<0.05). Self-reported respiratory symptoms improved in 14 patients (78%, P<0.05). Radiographic improvement post Atrium iCAST stent placement was achieved in 15 patients (83%). No deaths were related to airway stenting complications. Adverse events related to stents included migration (n=2, 9.5%), granulation tissue formation (n=2, 9.5%) and mucus plugging (n=1, 4.8%). Lobar stenting with balloon-expanding metallic stents appears feasible, safe and improves symptoms as well as radiographic atelectasis in patients with lobar airway stenosis in this small case series. Larger studies are needed to confirm this observation and to address long-term safety.