Balloon-expandable Stent Placement Research Articles

Coaxial Placement of Balloon-Expandable and Self-Expanding Stents: Impact on Crush Resistance and Luminal Recovery in a Benchtop Model

During endovascular interventions, coaxial deployment of stents may be required to preserve luminal gain. This study characterized in vitro the effect on crush resistance and postcompression recovery when 316L stainless steel balloon-expandable (BE) and laser-cut nitinol self-expanding (SE) venous stents were deployed coaxially. Various stent configurations were parallel-plate compressed from a fully expanded state to 50% diameter reduction (Criterion, Model 42; MTS, Eden Prairie, Minnesota) in a 37 °C ± 1 water bath. Coaxial deployments of SE stent inside BE stent and BE stent inside SE stent demonstrated higher crush resistances compared with each stent individually or their mathematical summation (analysis of variance P < .0001; pairwise comparison P < .01). The configuration of SE stent inside BE stent showed higher postcompression luminal recovery at 48.7% compared with that of BE stent inside SE stent at 27.5% (P = .0001). Coaxial deployment of SE stent inside BE stent may improve crush resistance and luminal recovery after compression in the appropriate clinical context.

Inelastic Deformation of Coronary Stents: Two-Level Model.

This study describes the internal structure of materials used to produce medical stents. A two-level elastoviscoplastic mathematical model, which sets the parameters and describes the processes at the grain level, was developed and numerically implemented. A separate study was conducted to identify the most dangerous deformation modes in the balloon-expandable stent placement using the finite-element method in COMSOL Multiphysics. As a result, the challenging strain state type required for setting the kinematic loading on a representative macrovolume in the two-level model was obtained. A yield surface for different deformation paths in the principal deformation space for stainless steel AISI 316L was obtained and the effect of grain size on the deformation behavior of this material was explored using the developed model.

Technical Feasibility and Histological Analysis of Balloon-Expandable Metallic Stent Placement in a Porcine Eustachian Tube

There is a clinical need to develop a stent to treat obstructive and refractory Eustachian tube dysfunction (ETD) after balloon Eustachian tuboplasty. An animal model for stent placement in the Eustachian tube (ET) is needed to develop optimal designs and materials, as stents for ETD have not been clinically applied. The purpose of this study was to evaluate the technical feasibility of stent placement and histological changes in a porcine ET model. Six ETs were evaluated in three pigs. Cobalt–chrome alloy stents with two different diameters were placed in the left and right ET of each animal (right, 3.5 mm; left, 2.5 mm). The outcomes were assessed by endoscopic and fluoroscopic imaging during the procedure, computed tomography after the procedure, and by histological examinations. Stent placement was technically successful in all specimens after metallic guiding sheaths were located in the nasopharyngeal end of the ET. The mean luminal diameters of the proximal, middle, and distal portions of the larger stents in the right ETs were 3.48 mm, 2.54 mm, and 2.15 mm, respectively. In the left ETs using smaller stents, these values were 2.49 mm, 1.73 mm, and 1.42 mm, respectively. The diameters of the inserted stents differed by stent location and the original diameter. Histological findings showed tissue hyperplasia with severe inflammatory cell infiltration at 4 weeks after stent placement. In conclusion, stent placement into the porcine ET was technically feasible, and stent-induced tissue hyperplasia was significantly evident. The luminal configuration of the placed ET stent changed according to its non-elastic nature and anatomical features of the porcine ET. Using this model, ET stents of various materials and designs with anti-inflammatory or anti-proliferative drugs can be optimized for future treatments of ET dysfunction.

Acute and medium term results of balloon expandable stent placement in the transverse arch—a multicenter pediatric interventional cardiology early career society study

Coarctation of the aorta represents 5-8% of all congenital heart disease. Although balloon expandable stents provide an established treatment option for native or recurrent coarctation, outcomes from transverse arch (TAO) stenting, including resolution of hypertension have not been well studied. This study aims to evaluate immediate and midterm results of TAO stenting in a multi-center retrospective cohort. TAO stenting was defined as stent placement traversing any head and neck vessel, with the primary intention of treating narrowing in the transverse aorta. Procedural details, complications and medications were assessed immediately post procedure, at 6 month follow-up and at most recent follow-up. Fifty-seven subjects, 12 (21%) native, and 45 (79%) surgically repaired aortic arches, from seven centers were included. Median age was 14 years (4 days-42 years), median weight 54 kg (1.1-141 kg). After intervention, the median directly measured arch gradient decreased from 20 mmHg (0-57 mmHg) to 0 mmHg (0-23 mmHg) (p < .001). The narrowest arch diameter increased from 9 mm (1.4-16 mm) to 14 mm (2.9-25 mm) (p < .001), with a median increase of 4.9 mm (1.1-10.1 mm). One or more arch branches were covered by the stent in 55 patients (96%). There were no serious adverse events. Two patients warranted stent repositioning following migration during deployment. There were no late complications. There were 8 reinterventions, 7 planned, and 1 unplanned (6 catheterizations, 2 surgeries). Antihypertensive management was continued in 19 (40%) at a median follow-up of 3.2 years (0.4-7.3 years). TAO stenting can be useful in selected patients for resolution of stenosis with minimal complications. This subset of patients are likely to continue on antihypertensive medications despite resolution of stenosis.

Long-term management and outcomes of tracheobronchial stent by flexible bronchoscopy in infants

Tracheobronchial (TB) lumen narrowing may require prolonged positive-pressure ventilation, endotracheal tube intubation or even surgical interventions. Therapeutic flexible bronchoscopy (TFB) of balloon-expandable metallic stent (BEMS) placement and subsequent forceps, laser and balloon dilatation management might be less invasive and helpful. This study aimed to analyse the placement, follow-up management with TFB and long-term outcomes in small infants with BEMS. This retrospective study reviewed the medical records and associated TFB videos of infants with a maximum body weight (BW) of 5.0 kg who had TB BEMS placement from January 2005 to December 2017 at our institution. All TFB procedures were supported with a novel noninvasive ventilation, nasopharyngeal oxygen with intermittent nose closure and abdominal compression. Forty-one BEMSs were placed in 24 infants. The mean BW and mean age were 4.0 ± 0.7 kg and 4.9 ± 2.4 months, respectively. There were 20, 8 and 13 stents located in trachea, carina and main-stem bronchi, respectively. Seven infants with 13 stents died without obvious stent-related mortality. Seven stents in five infants were successfully retrieved by rigid endoscopy (RE). At placement, the diameters of 28 tracheal and 21 bronchial stents were 7.5 ± 1.1 (4-10) and 5.4 ± 0.9 (4-8) mm, respectively. These implanted BEMSs could be gradually and significantly (p < 0.01) expanded. At the end of the follow-up period, all the remaining 21 stents in 12 infants were functional. The diameters of the 14 remaining tracheal and 13 remaining bronchial stents were 9.6 ± 2.0 (8-14) and 7.2 ± 1.4 (4-10) mm, respectively. BEMSs are practical and effective in selected small infants with benign TB narrowing and can be safely implanted and managed with TFB, and finally retrieved by RE.

DOZ047.106: Internal stents and external splints for complex airway obstruction

Abstract Background Life-threatening airway obstruction due to severe tracheobronchial stenosis or tracheobronchomalacia not amenable to tracheobronchopexy or resection is still a challenge, and warrants aggressive innovative strategies. In this study, our experience with placement of balloon-expandable stents and/or external bioabsorbable splints in children with severe tracheobronchial obstruction was reviewed. Methods All patients with symptomatic severe airway obstruction who underwent interaluminal stent and/or external splint placement (1997–2019) were retrospectively reviewed. The data collected included age, type of obstruction (stenosis or malacia), associated malformations, technical and clinical success, complications, and outcomes. Airway stents were placed under fluoroscopic guidance. Bioabsorbable splints (RapidSorb, Synthes CMF) were custom molded and then secured externally on the collapsing areas under simultaneous bronchoscopic and direct visualization. Results Seventeen patients underwent 14 airway stents (trachea = 5, bronchi = 9) and/or 11 external bioabsorbable splints (trachea = 5, bronchi = 6) at a median age of 5 months (IQR 3–9 months). Fourteen stents were placed in 8 patients, 10 external splints in 8 patients; one patient had two stents and one splint. Indications for stenting were stenotic airways in 11 patients (postoperative = 7, congenital = 4) and severe distal airway malacia in 3. All the external bioabsorbable splints were placed in patients with severe airway malacia secondary to lack of cartilaginous support and/or extrinsic compression. During follow-up 3/9 stented patients and 3/9 splinted patients did not experience any significant adverse events. Six of nine stented patients experienced serious adverse events: significant in-stent stenosis (n = 3), stent migration, and obstructive granulation tissue (n = 1), erosion through airway wall (n = 1), and death (n = 2). Of the nine splinted patients, one bronchial splint fractured, requiring replacement, and five patients required tracheostomies for continued respiratory failure from unilateral pulmonary hypoplasia and residual distal tracheal stenosis (n = 1), severe tracheomalacia (n = 2), subglottic stenosis (n = 1), and laryngeal cleft (n = 1). One patient died a week after surgery. Conclusion Airway internal stenting and external bioabsorbable splinting are effective therapeutic strategies for selected patients with complex airway abnormalities. Bioabsorbable splints are effective in maintaining airway patency, and being absorbable allow for age-proportional growth of the airways. Airway stents can be associated with significant adverse events and therefore should be reserved for patients who have failed other therapeutical strategies.

Analysis of portal vein thrombosis after liver transplantation.

Portal vein thrombosis (PVT) is one of the most deadly complications after orthotopic liver transplantation (OLT). This study aimed to identify risk factors and summarize the experience of PVT management after OLT. The clinical data of 407 adult patients received OLT from July 2011 to December 2015 was retrospectively investigated. The incidence rate of PVT was 2.9% (12/407). Pre-transplant PVT (P = 0.001), post-operative transfusion of erythrocyte (P = 0.006) and platelet (P = 0.036) were significantly associated with PVT in the univariate analysis and the appearance of pre-transplant PVT (P = 0.002, odds ratio 6.05) was the independent risk factor according to binary logistic regression. Among patients with PVT, three cases (3/12) received balloon dilation through selective catheterization of portal vein, five (5/12) received balloon-expandable stent placement, three (3/12) received thrombectomy and surgical revascularization and one (1/12) received retransplantation. Six patients (6/12) died from various complications and the remaining six were followed up with normal liver function and patent portal vein. The risk factors were pre-transplant PVT and post-operative transfusion of erythrocyte and platelet. To recipients with high risk, early diagnosis and prompt management of PVT are essential to improve prognosis.

03:18 PM Abstract No. 270 Parallel TIPS versus DIPS for second percutaneous portosystemic shunt placement in cirrhotic patients with an existing TIPS

A second portosystemic shunt (sPSS) may be needed in patients with recurrent variceal bleeding or persistent ascites despite an existing transjugular intrahepatic portosystemic shunt (TIPS) due to insufficient portal decompression or shunt occlusion refractory to recanalization. There is no consensus on the best method for sPSS creation. The goal of this study was to compare the technical and clinical outcomes of placing a parallel TIPS (pTIPS) versus direct intrahepatic portocaval shunt (DIPS) as the sPSS. From 2002-2017, a pTIPS (n = 12; median age 62 y, MELD 13) or DIPS (n = 8; 57 y, 12) was placed in 20 patients with an existing TIPS and recurrent symptoms. sPSS indication, procedure details, technical and clinical success rates, and complications were retrospectively reviewed and compared. A sPSS was indicated for persistent ascites or recurrent variceal bleeding in 6 and 6 patients, respectively, in the pTIPS group and 6 and 2 patients in the DIPS group. The existing TIPS was patent in 5/12 patients in the pTIPS group and 4/8 in the DIPS group; the rest were chronically occluded. DIPS was specifically chosen in 5 cases due to anatomical limitations posed by the existing TIPS. In one pTIPS procedure, the existing occluded TIPS prevented full expansion of the new pTIPS, requiring balloon expandable stent placement. Stent-grafts were used in all cases (pTIPS: diameter 10 mm n=8, 8 mm n=4; DIPS: 10 mm n=5, 8 mm n=3, 7 mm n=1). Technical success was 100% in both groups. Mean procedure time for DIPS trended towards shorter versus pTIPS (73±22 vs 97±63 min, p=0.35) with a wider range in pTIPS procedure times (50-101 vs 72-262 min). Mean portosystemic gradient reductions after pTIPS (14.8±4.3 to 6.6±2.6 mm Hg) and DIPS (12.4±3.8 to 5.6±2.9) were similar. Ascites improved and variceal bleeding resolved in all patients. Hepatic encephalopathy worsened in 2 pTIPS and 1 DIPS patients. No acute liver failure occurred. Two pTIPS patients died within 30 days due to sepsis and lung cancer. Technical and clinical outcomes were similar between pTIPS and DIPS for sPSS creation. DIPS may be technically preferable due to anatomical issues in some patients with an existing TIPS.

Decrease in lipid rich plaque during percutaneous coronary intervention: reality or artefact? An observational study using Near-Infrared Spectroscopy

Background: Lipid rich plaque (LRP) content has been shown to decrease after high-pressure balloon-expandable stent placement. LRPs are quantified by the lipid core burden index (LCBI) on near-infrared spectroscopy (NIRS). We aim to evaluate the changes in LRP content during sequential steps of non-urgent percutaneous coronary intervention (PCI) using low-pressures. Methods: A total of 10 patients with a LCBI>200 on pre-stenting NIRS and successful PCI with the self-apposing stent were included. Quantitative coronary angiography was used to assess luminal diameters. IVUS-NIRS was performed pre-stenting after initial pre-dilatation, post-stenting and after post-dilatation to assess the LCBI and the plaque burden to evaluate plaque modification. IVUS-NIRS is analyzed for all stented segments including proximal and distal stent edges using dedicated software. Results: Mean balloon pressure was 11.4±3.8 atm. Pre-stent reference vessel diameter (RVD) was 3.3±0.6 mm, Dmax was 3.9±0.9 mm. Mean LCBI of the stented segment was 160±96 pre-stenting, 32±49 post-stenting and 21±35 after post-dilatation (p=0.001). The plaque burden remained constant in the stented segment; 0.48±0.1 mm² pre-stenting vs. 0.51±0.1 mm² post-stenting vs. 0.48±0 mm² after final post-dilatation (p=0.14). Conclusions: Serial IVUS-NIRS demonstrated a significant decrease of LCBI in the stented segment from pre-stenting to post-stenting and after post-dilatations, while plaque burden remained unaltered throughout PCI in relatively large RVDs. This discrepancy might possible explained by the fact that NIRS might be not detecting the lipid in larger RVDs since it is only validated in small RVDs. Research including larger numbers of patients are warranted to confirm this concept.

Stent implantation for relief of pulmonary artery branch stenosis

Branch pulmonary artery stenosis is one of the common congenital heart disease. Stent implantation to relieve branch pulmonary artery stenosis (BPAS) is an alternative to failed surgical or balloon angioplasty. The aim of this study was to explore the indication, methods and complications of using balloon expandable stent placement to treat branch pulmonary artery stenosis, and evaluate the results of stent implantation in the treatment of branch pulmonary artery stenosis. From August 2005 to December 2012, 19 patients underwent an attempt at stent implantation. The median age of those patients was 9.1 years (range 4.0-15.0 years). The median weight was 31.7 kg (range 17.0-60.5 kg); 14/19 patients underwent post surgical repair of tetralogy of Fallot, one patient received post surgical repair of pulmonary atresia with ventricular septal defect, one patient underwent post surgical repair of pulmonary atresia with intact septum, one with native left BPAS, and one was after surgical repair of aortopulmonary window and the other truncus arteriosus. CP stent and NuMED Balloon-in-Balloon catheter were selected according to digital subtracted angiography measurements. After checking for correct position by angiography, the inner balloon and outer balloon was inflated successively to expand the stent to desired diameter. Statistical analysis was performed with the unpaired Student t test. A total of 26 stents were implanted successfully in 19 patients. The systolic gradient across the stenosis fell from a median of (36.0 ± 18.3) to (3.8 ± 3.4) mmHg (P < 0.01, 1 mmHg = 0.133 kPa) and the diameter of the narrowest segment improved from (6.0 ± 1.9) to (11.6 ± 3.1) mm (P < 0.01). The right ventricle to aortic pressure ratio fell from 0.68 to 0.49 (P < 0.01). Complications included the following: two stents were malpositioned in the right ventricular outflow tract and one balloon ruptured when dilated the hole of the stent. No other complications occurred. All patients were followed up for 6 months to 6.0 (2.5 ± 1.8) years. One patient underwent stent re-dilation in order to accommodate somatic growth two years later. Balloon expandable stents are safe and effective in relieving BPAS. Stent implantation should be considered the treatment of choice for most patients with BPAS. Stents placed into growing children will require further dilation to keep up with normal somatic growth. Intermediate and long-term follow up studies have shown excellent results after further dilation over time.

Placement of balloon-expandable stents in coarcation of the aorta: Initial results and short-term follow up

We report preliminary result and short term follow up (up to 5 years)of balloon-expandable stents for the coarctation of the aorta (COA). Using balloon-expandable stents gained acceptance over the past years, as a modality of treatment for COA. However, use of these stents may create disruption of the aortic wall or aneurysm at the stents end points. Our experience using Palmaz stent in half of the patients mounted on a balloon dilatation catheter. The rest of the patients received Covered CP Stent. All patients had significant improvement without any complications. Twenty five patents with mean age 18 years range from 9 to 45 with COA underwent stent implantation. Nine patients were diagnosed with native COA and 16 had previous surgical, balloon dilatation or both, to relieve their coarcation; but had residual/recurrent gradient. A femoral vessels access performed for such procedure and angio-grams were obtained pre and post stent implantation. BP was continuously monitored during the procedure. All patients were maintained on aspirin for at least 6 months post procedure. Immediately after stent implantation the peak systolic gradient (mean (SD)) fell from 35 mm Hg (15.6) to 3.8 (4.3) (mm Hg). ( p < 0.05). The diameter of the stenotic lesion increased from 6.5 (3.0) to13.5 (3.0) mm ( p < 0.05). There were no deaths or procedure related complications. Measured one day after stent placement, the descending aorta velocity dropped from (mean (SD)) 3.7 (0.58) m/s to 2.3 (0.6) m/s. ( p < 0.05). At median follow up of 24 months, the clinical gradient dropped from (mean (SD)) 36 (18) mm Hg pre intervention to 4 (9) p < 0.05) mm Hg. Seven patient (28%) required re-dilatation at a later stage for re-stenosis. The average systolic and diastolic blood pressure at follow up was at the 5th percentile. Nine patients (28%) were still on antihypertensive medications compare to 13 patients (52%) at the time of stent implantation. Stent implantation for the treatment of coarctation of the aorta appears to have very low morbidity and mortality, and reasonable intermediate term results. A long term follow up is needed.

Stent effects on duplex velocity estimates

BackgroundDoppler-derived velocity criteria used to define the presence and severity of in-stent restenosis after percutaneous angioplasty and endoluminal stenting have been called into question. This study uses an in vitro flow model to examine Doppler-derived velocities after placement of balloon-expandable and self-expanding endoluminal stents (BES and SES). MethodsAn in vitro vascular circuit model consisting of a pulsatile pump, tubing, and a conduit was created. The pump was programmed to replicate the Doppler spectral waveform pattern of the renal and carotid arteries. Peak systolic velocity (PSV) and end diastolic velocity (EDV) were estimated at five distinct conduit locations. Three replicate velocity measurements were made at each location. After initial velocity estimates, a BES or an SES was deployed within the conduit. ResultsMean ± standard error PSV was 95.8 ± 2.6 cm/s, 97.0 ± 2.7 cm/s, and 101.4 ± 2.7 cm/s for unstented, BES and SES, respectively. PSV estimates were increased between unstented and stented conduits when SESs were present. The increase in mean systolic velocity of 6.4% observed with SES was statistically significant (P < 0.05). EDV values did not differ significantly across conditions. Mean ± standard error EDV was 36.2 ± 1.0 cm/s, 37.3 ± 1.1 cm/s, and 37.2 ± 1.1 cm/s for unstented, BES, and SES, respectively. ConclusionThe presence of an SES was associated with a less than 7% change in estimated PSV. These results suggest that Doppler velocity estimates for renal and carotid arteries are not materially affected by either BES or SES.

Balloon-Expandable Stent Placement in Patients with Immediate Reocclusion after Initial Successful Thrombolysis of Acute Middle Cerebral Arterial Obstruction

We present the results of our approach for treating 12 consecutive cases of acute middle cerebral artery (MCA) stroke by performing balloon-expandable stent (BES) placement after immediate reocclusion due to the underlying stenosis after intra-arterial thrombolysis (IAT). We retrospectively reviewed the clinical outcomes of 12 patients with acute MCA stroke who underwent recanalization by BES placement in an underlying stenosis after IAT. The time to treatment, urokinase dose, duration of the procedure, recanalization rates and symptomatic hemorrhage were analyzed. Clinical outcome measures were assessed on admission and at discharge (the National Institutes of Health stroke scores [NIHSS]) as well as three months after treatment (modified Rankin scales [mRS]). The median NIHSS score on admission was 8.6. Four patients received IV rtPA. The median time from symptom onset to IAT was 236 minutes and the median duration of IAT was 62 minutes. The median dose of urokinase was 140,000 units. Initial recanalization after stent deployment (thrombolysis in cerebral ischemia attack grade of II or III) was achieved in all patients. Two patients died in the hospital due to aspiration pneumonia during medical management. In two patients, in-stent reocclusion occurred within 48 hours after stent deployment. At discharge, the median NIHSS score in ten patients (including the patients with reobstruction) was 2.4. The three-month outcome was excellent (mRS, 0-1) in eight patients. In this study, BES deployment was safe and effective in patients with an immediately reoccluded MCA after successful IAT.

Invited commentary

The increasingly aggressive endovascular management of tibial artery occlusive disease is understandable given the fact that endovascular surgeons have routinely acquired increased technical skill and gained access to enabling endovascular hardware. However, the many options available to treat atheromatous lesions, including balloon angioplasty, cryoplasty, excisional atherectomy, rotational atherectomy, self-expanding stent placement, covered stent placement, balloon expandable stent placement, and drug-eluting stent placement, have driven the treatment of lesions faster than data has provided guidance. Unlike trials of the use of drug-eluting stents in the superficial femoral artery in which no benefit was noted,1Duda S.H. Bosiers M. Lammer J. Scheinert D. Zeller T. Tielbeek A. et al.Sirolimus-eluting versus bare nitinol stent for obstructive superficial femoral artery disease: the SIROCCO II trial.J Vasc Interv Radiol. 2005; 16: 331-338Abstract Full Text Full Text PDF PubMed Scopus (395) Google Scholar, 2Duda S.H. Bosiers M. Lammer J. Scheinert D. Zeller T. Oliva V. et al.Drug-eluting and bare nitinol stents for the treatment of atherosclerotic lesions in the superficial femoral artery: long-term results from the SIROCCO trial.J Endovasc Ther. 2006; 13: 701-710Crossref PubMed Scopus (445) Google Scholar the authors of the Drug Eluting Stents In the Critically Ischemic Lower Leg (DESTINY) trial provide us with level I evidence to support the use of drug-eluting stents over bare-metal stents in the management of tibial arterial lesions. Interestingly, a similar report has been published in an electronic format since the editorial process began on this article.3Rastan A. Tepe G. Krankenberg H. Zahorsky R. Beschorner U. Noory E. et al.Sirolimus-eluting stents vs. bare-metal stents for treatment of focal lesions in infrapopliteal arteries: a double-blind, multi-centre, randomized clinical trial.Eur Heart J. 2011; 32: 2274-2281Crossref PubMed Scopus (164) Google Scholar Results are surprisingly similar, with primary patency rates of 80.6% for sirolimus-eluting stents deployed in tibial arteries and 55.6% for lesions treated with bare-metal stents (P =.004) vs the 85% and 54% noted in this study. There is a distinct historical parallel between this increasingly aggressive endovascular treatment of tibial disease and the surgical treatment of tibial disease in the mid-1980s, when bypass grafts were performed both with autogenous vein and with prosthetic conduits. Data from carefully performed clinical trials demonstrated the superiority of autogenous conduit use and thus defined a standard of care.4Bergan J.J. Veith F.J. Bernhard V.M. Yao J.S. Flinn W.R. Gupta S.K. et al.Randomization of autogenous vein and polytetrafluorethylene grafts in femoral-distal reconstruction.Surgery. 1982; 92: 921-930PubMed Google Scholar, 5Veith F.J. Gupta S.K. Ascer E. White-Flores S. Samson R.H. Scher L.A. et al.Six-year prospective multicenter randomized comparison of autologous saphenous vein and expanded polytetrafluoroethylene grafts in infrainguinal arterial reconstructions.J Vasc Surg. 1986; 3: 104-114PubMed Scopus (944) Google Scholar Similarly, a new standard has been set with respect to the use of drug-eluting stents in the tibial arteries. Many basic questions remain unanswered, however. The most fundamental is how the use of stents fits into the overall scheme of the endovascular management of tibial vessel occlusive disease. The effectiveness of a strategy involving the use of drug-eluting stents vs angioplasty alone, atherectomy, or any other adjunctive measure remains untested. Furthermore, although the endovascular surgeon can now treat tibial artery lesions with drug-eluting stents and can point to specific data to support this approach, this study has important limitations that limit its generalizability. The lesions treated in this study were <40 mm in length, which, of course, represents a relatively small subset of the patients with treatable tibial disease. An intervention to improve the outcomes of recanalization of long tibial segments remains elusive. We are in the infancy of our understanding of the best means of treating tibial vessel occlusive disease, but we now have some level I data to guide our decision making. However, of all of the treatment paradigms for the management of tibial disease, this may be the most expensive. Further research will help define the cost-effectiveness of this approach. The next step in the evolution of our understanding of the most appropriate treatment of tibial disease will compare the use of drug-eluting stents vs other available technologies, such as balloon angioplasty and atherectomy, for lesions suitable for endovascular treatment. Randomized comparison of everolimus-eluting versus bare-metal stents in patients with critical limb ischemia and infrapopliteal arterial occlusive diseaseJournal of Vascular SurgeryVol. 55Issue 2PreviewCritical limb ischemia, the most severe form of peripheral arterial disease, results in extremity amputation if left untreated. Endovascular recanalization of stenotic or occluded infrapopliteal arteries has recently emerged as an effective form of therapy, although the duration of patency is typically limited by restenosis. Recently, it has been suggested that drug-eluting stents originally developed for the coronary arteries might also be effective in preventing restenosis in the infrapopliteal arteries. 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A Prospective Evaluation of the Impact of Balloon-Expandable Palmaz Stent Placement in Aortic Neck During EVAR

A Prospective Evaluation of the Impact of Balloon-Expandable Palmaz Stent Placement in Aortic Neck During EVAR

Recanalization Results After Intracranial Stenting of Atherosclerotic Stenoses

The purpose of this investigation was to provide a detailed description of the angiographic results after stenting of high-grade intracranial stenosis using balloon-expandable stents. Forty consecutive patients with symptomatic atherosclerotic intracranial stenosis >50% received endovascular treatment by placement of balloon-expandable stents using the concept of slight underdilation and strict avoidance of overdilation. Intra-arterial digital subtraction angiography images before and after stenting in the same projection were reviewed for pre- and post-therapeutic measurement of the degree of stenosis and evaluation of morphologic criteria like plaque coverage, stent apposition, patency of side branches, and signs of dissection or vasospasm. Stenting decreased the mean percentage stenosis from 76.2 (WASID criteria) to 20.8%. Residual stenosis ranged from 0 to 55% with residual stenosis >50% in two of 40 cases. Technical success rate was 95%. There were no major vessel complications, but minor abnormalities like incomplete stent apposition (8/40) or plaque coverage (7/40), incomplete filling of side branches (13/40), and minor dissections after stenting (2/40) were seen. One case with incomplete stent apposition and two cases with side branch compromise were associated with clinical symptoms. In conclusion, intracranial stenting with slight underdilation avoided major vessel complication and created reliable luminal gain. Suboptimal recanalization results were frequently detected and may be the source of neurological complications in individual cases.

Use of a balloon-expandable metallic stent for treatment of nasopharyngeal stenosis in dogs and cats: six cases (2005–2007)

To determine outcome associated with use of a balloon-expandable metallic stent for treatment of nasopharyngeal stenosis in dogs and cats. Retrospective case series. 3 dogs and 3 cats. All 6 animals had severe inspiratory stertor at initial examination. Two animals had no orifice present at the stenosis. Nasopharyngeal stenosis was diagnosed and stent size determined by use of computed tomography. A percutaneous transluminal angioplasty balloon premounted with a balloon-expandable metallic stent was placed over a guidewire, advanced through the stenotic lesion under fluoroscopic and rhinoscopic guidance, and dilated to restore patency. All animals had immediate resolution of clinical signs after stent placement. The procedure took a median of 38 minutes (range, 22 to 70 minutes). One animal with a stenosis located far caudally needed the tip of the stent resected because of hairball entrapment and exaggerated swallowing. Both animals without an orifice in the stenosis had tissue in-growth requiring a covered stent. All animals were reexamined 6 to 12 weeks after treatment via rhinoscopy, radiography, computed tomography, or a combination of techniques. All animals lacked signs of discomfort; 5 of 6 were breathing normally 12 to 28 months after the procedure. Transnasal balloon-expandable metallic stent placement may represent a rapid, safe, noninvasive, and effective treatment in animals with nasopharyngeal stenosis. If the stenosis is extremely caudal in the nasopharynx, serial balloon dilatation might be considered prior to stent placement. A covered stent should be considered initially if the stenosis is completely closed.

Percutaneous Transluminal Angioplasty (PTA) Alone versus PTA with Balloon-expandable Stent Placement for Short-segment Femoropopliteal Artery Disease: A Metaanalysis of Randomized Trials

To evaluate and compare the results of percutaneous transluminal angioplasty (PTA) and stent placement to treat femoropopliteal artery occlusive disease. Published data of randomized clinical trials comparing the results of PTA and stent placement for femoropopliteal artery occlusive disease were analyzed. Proportions were combined, and the odds ratio (OR) with its 95% CI was used as the effect size estimate. Seven studies published in 1999 or later (614 limbs in 519 patients) were included in this metaanalysis, in which 323 limbs underwent PTA and 291 limbs underwent PTA followed by balloon-expandable stent placement. In the combined results of PTA versus PTA plus stent placement, a significant difference in primary patency at 6 months (OR, 0.47; 95% CI, 0.27-0.84; P < .05) was found, but no significant difference could be found in primary patency at 12 months (OR, 1.27; 95% CI, 0.87-1.86; P > .05) or 24 months (OR, 1.22; 95% CI, 0.81-1.82; P > .05) or in secondary patency at 12 months (OR, 1.34; 95% CI, 0.78-2.30; P > .05). In the treatment of femoropopliteal artery occlusive disease (< or =10 cm), higher primary patency rates can be expected at 6 months with PTA followed by implantation of balloon-expandable stents versus PTA alone, but PTA with stent placement does not produce better long-term primary results and secondary patency rates than PTA alone.

Intracranial Stenting of Severe Symptomatic Intracranial Stenosis: Results of 100 Consecutive Patients

There are a few reports regarding the outcome evaluation of balloon-expandable intracranial stent placement (BEICS). The purpose of our study was to evaluate the outcome and factors related to the adverse events (AEs) of BEICS. We evaluated 100 consecutive patients who underwent BEICS. We assessed the procedural success (residual stenosis < 50%), AEs (minor strokes, major strokes, and death), clinical outcome, and restenosis (> 50%) at 6 months. We also analyzed 18 factors including symptom patterns related to AE rate. Symptom patterns revealed 1) stable patients (n = 73) with improving, stationary, or resolved symptoms; and 2) unstable patients (n = 27) with gradual worsening or fluctuating symptoms (National Institutes of Health Stroke Scale [NIHSS] > or = 4) within 2 days before stent placement. The procedural success rate was 99%. Overall, there were 10 (10%) AEs within the 6 months: 4 (4%) minor strokes, 3 (3%) major strokes, and 3 (3%) deaths including a death from myocardial infarction. AE rate was 4.1% in stable and 25.9% in unstable patients. Restenosis at 6 months revealed 0% (0/59). Good outcome (modified Rankin Scale < or = 2) at 6 months was 97% (71/73) in stable and 67% (18/27) in unstable patients. Stepwise logistic regression model revealed that symptom pattern (unstable versus stable) was the only significant risk factor (OR, 8.167; 95% CI, 1.933-34.500; P = .004). BEICS revealed a low AE and good outcome rate at 6 months, especially in the stable patients. Midterm outcome was also favorable in the unstable patient group.

Dual guidewire placement to enhance arch vessel origin identification: A simple technique to facilitate ostial aortic arch vessel stenting

Orificial occlusive lesion involving the aortic arch vessels is commonly treated with balloon-expandable stent placement. Stenting of such a lesion typically involves an initial aortogram to precisely identify the vessel origin, followed by deployment of a balloon-expandable stent to cover the ostial lesion. We report a simple technique of an antegrade femoral guidewire placement along the outer curvature of the aortic arch to facilitate the identification of the origin of aortic arch vessels. This enhanced ostial visualization enables a precise positioning and deployment of a balloon-expandable stent in aortic arch vessels. This dual guidewire technique facilitates the visual identification of arch vessel origin and reduces potential contrast requirement, which provides procedural benefit in patients with renal insufficiency or contrast allergy.