Twelve-Month Results of the Nitinol Astron Stent in Iliac Artery Lesions.

PURPOSE: To evaluate the safety and efficacy of a self-expanding bare-metal nitinol stent (Astron; BIOTRONIK AG, Bülach, Switzerland) for the treatment of atherosclerotic lesions in the common and external iliac arteries. This study tested the hypothesis that the major adverse event (MAE) rate at 12 months was less than or equal to a performance goal of 15%. MATERIALS AND METHODS: In a prospective study that began in November 2011, 161 patients with symptomatic iliac lesions were treated with an Astron stent in the United States, Canada, and Austria. The primary endpoint was a composite rate of procedure- and stent-related MAEs at 12 months that included 30-day mortality, clinically indicated target lesion revascularization (TLR), and index limb amputation. RESULTS: The MAE rate at 12 months was 2.1% (3/146; [95% CI: 0.4% to 5.9%]; p < 0.001). The acute procedural success and 30-day clinical success outcomes were both 95% (153/161). The primary patency rate at 12 months was 89.8% (115/128). The comparison of baseline and 12-month Ankle Brachial Index (ABI) measurements showed a mean increase of 0.23 ± 0.19 (p < 0.001). The Walking Impairment Questionnaire (WIQ) PAD specific score, walking distance score, walking speed score and stair climbing score paired each showed a significant increase from baseline to 12 months (p<0.001). CONCLUSIONS: The Astron stent system was shown to be safe and effective in the treatment of patients with atherosclerotic disease. The observed MAE rate met the pre-specified performance goal of 15%. The stent demonstrated a high 12-month primary patency rate and showed improvement in quality of life measures.

Predictors of embolization during protected renal artery angioplasty and stenting: Role of antiplatelet therapy.

OBJECTIVE: The objective of this study was to identify the predictors of distal embolization (DE) during protected renal artery angioplasty and stenting. BACKGROUND: DE may contribute to worsening renal function after renal artery stenting. The factors associated with DE, rates of platelet-rich emboli, and treatments that may prevent DE during renal stenting have not been evaluated. METHODS: The current study evaluated patients randomized to receive an embolic protection device (EPD) in the RESIST trial. Forty-two patients were identified for inclusion in this study. These patients were further randomized to abciximab (N = 22) or placebo (N = 20). Modification in Diet in Renal Disease glomerular filtration rate (GFR) was used as the primary measure of renal function. Creatinine was measured by a modified Jaffe reaction using the IDMS-traceable assay. The primary endpoint was capture of platelet rich emboli in the angioguard basket. RESULTS: DE occurred in 15/42 (35%) of the patients and platelet rich DE in 10 (24%) of the patients who received an EPD. Of the angiographic characteristics only lesion length was significantly higher in patients with DE (16 +/- 7 mm vs. 10 +/- 5 mm, P = 0.04). Preprocedural abciximab reduced DE from 42 to 8% (P = 0.02). The rate of platelet rich emboli was 50% with neither abciximab nor a thienopyridine, 36% with thienopyridine only, 15% abciximab only, and 0% in patients who received both a thienopyridine and abciximab. Only Abciximab use was associated with improved renal function at 1-month, thienopyridine was not. Angiographic characteristics including percent stenosis, minimal luminal diameter (MLD), reference diameter, change in MLD, contrast volume, and procedure time were not predictors of DE during renal stenting. CONCLUSION: Capture of DE and specifically platelet DE are common during protected renal stenting using a filter-type EPD. Abciximab use, and potentially combined thienopyridine and abciximab use, decreased the rate of platelet rich DE; however, only abciximab improved renal function at 1-month.

Stent fracture in the coronary and peripheral arteries.

Inherent risks of stenting include restenosis and thrombosis. Recently, stent fractures have been recognized as a complication that may result in thrombosis, perforation, restenosis, and migration of the stent resulting in morbidity and mortality. Stent fractures were originally seen in the superficial femoral arteries but have since then been reported in almost all vascular sites including the coronary, renal, carotid, iliac, and femoropopliteal arteries. Fractures are the result of the complex interplay between stent manufacturing, the stented segment, pulsatile and nonpulsatile biomechanical forces, and plaque morphology at a particular vascular site. The presentation of a patient with a fracture is highly variable, ranging from asymptomatic in nature, detected on routine screening without any sequelae, to sudden cardiac death related to a thrombosed coronary artery. Despite being recognized as an important complication, consensus on routine surveillance and diagnostic methods to detect fractures continues to be lacking. Fortunately, most cases are relatively benign and can be managed conservatively if detected. In the setting of recurrent symptoms, further intervention is usually sought. In review of the literature most cases are managed with placement of a stent over the fractured area, the stent-in-stent technique, but several other alternatives may be available. As the knowledge of the variables that make stents prone to fracture are identified, better technologies and techniques can be employed to minimize the risk of this complication. This article reviews the available literature on stent fractures and complications using data found on PubMed, MEDLINE, the Manufacturer and User Facility Device Experience (MAUDE) database, and the Cochrane databases.

Stent placement for long-segment total occlusion of an aberrant right subclavian artery: A 7-year follow-up.

An aberrant origin of the right subclavian artery arising as the most distal vessel from the aortic arch is an uncommon but clinically important anomaly. Its abnormal course may result in esophageal compression with dysphagia, or tracheal compression resulting in asthma or stridor, and can greatly complicate radial artery access for coronary angiography. When an aberrant right subclavian artery is obstructed by atherosclerotic plaque, it may produce symptoms of arm ischemia such as pain and weakness. For the past 75 years, the standard treatment approach for symptomatic aberrant right subclavian artery has been surgical correction. There are only three case reports of percutaneous therapy, all for nonocclusive stenosis. There are no reported cases of percutaneous treatment of a completely occluded aberrant right subclavian artery. We report a patient with exertional right arm heaviness and weakness who was found to have a 60-mm long aberrant right subclavian artery occlusion. The blockage was successfully treated with angioplasty and placement of a single stent using percutaneous vascular access. Chest computerized tomography and duplex ultrasonography 5 years after treatment demonstrated a patent stent. At 7-year follow-up, she remained symptom-free and had a normal radial pulse. This case represents the first report of total occlusion of aberrant right subclavian artery treated percutaneously. Long-term durability supports this as a viable alternative to surgery in appropriately selected patients.

Safety and Long-Term Patency of Endovascular Therapy for Infrarenal Aortic Disease: Single-Center Experience and Review of the Literature.

OBJECTIVES: Endovascular therapy (EVT) has emerged as an alternative to surgery for the treatment of symptomatic infrarenal aortic stenosis (IAS). However, long-term outcomes with EVT are unknown. METHODS: We performed a retrospective review of patients with IAS treated with the endovascular approach at the University of Toledo Medical Center, Toledo, Ohio. We compared our single-center study (SCS) with a review of published studies (ROS) regarding complications, patency rate (PR), and repeat intervention rate (RIR). Pearson's Chi-square or Fisher's exact test, and the Student's t-test or Mann-Whitney U-test, were used for categorical and continuous variables, respectively. For the ROS data, we used a pooled mean of means. RESULTS: A total of 25 patients from the SCS were compared with 698 patients from the ROS data. Mean age was 63 years vs 58 years, females comprised 48% vs 54%, Rutherford class 3 comprised 68% vs 69%, and mean follow-up duration was 67 months vs 44 months in SCS vs ROS, respectively. PR at 12 months was 96% vs 90%, while PR at maximum time-period was 92% vs 76% in SCS vs ROS, respectively. RIR in SCS was 4% at 12 months and 8% at the maximum time period (20.2 years). RIR in ROS was 24% at the maximum time period (10 years). The mortality rate was 0% in the SCS arm vs 3.4% in the ROS arm. CONCLUSION: EVT is highly effective and safe, and was associated with excellent patency rates at long-term follow-up.

Embolic protection and platelet inhibition during renal artery stenting.

BACKGROUND: Preservation of renal function is an important objective of renal artery stent procedures. Although atheroembolization can cause renal dysfunction during renal stent procedures, whether adjunctive use of embolic protection devices or glycoprotein IIb/IIIa inhibitors improves renal function is unknown. METHODS AND RESULTS: One hundred patients undergoing renal artery stenting at 7 centers were randomly assigned to an open-label embolic protection device, Angioguard, or double-blind use of a platelet glycoprotein IIb/IIIa inhibitor, abciximab, in a 2x2 factorial design. The main effects of treatments and their interaction were assessed on percentage change in Modification in Diet in Renal Disease-derived glomerular filtration rate from baseline to 1 month using centrally analyzed creatinine. Filter devices were analyzed for the presence of platelet-rich thrombus. With stenting alone, stenting and embolic protection, and stenting with abciximab alone, glomerular filtration rate declined (P<0.05), but with combination therapy, it did not decline and was superior to the other allocations in the 2x2 design (P<0.01). The main effects of treatment demonstrated no overall improvement in glomerular filtration rate; although abciximab was superior to placebo (0+/-27% versus -10+/-20%; P<0.05), embolic protection was not (-1+/-28% versus -10+/-20%; P=0.08). An interaction was observed between abciximab and embolic protection (P<0.05), favoring combination treatment. Abciximab reduced the occurrence of platelet-rich emboli in the filters from 42% to 7% (P<0.01). CONCLUSIONS: Renal artery stenting alone, stenting with embolic protection, and stenting with abciximab were associated with a decline in glomerular filtration rate. An unanticipated interaction between Angioguard and abciximab was seen, with combination therapy better than no treatment or either treatment alone.

Passing sheaths and electrode catheters through inferior vena cava filters: safer than we think?

Inferior vena cava (IVC) filters are being inserted with increasing frequency for the prevention of pulmonary embolus. Previous case reports have documented the passage of up to three electrode catheters or an individual long sheath through an IVC filter. The current report expands on prior series with regard to the number of devices used. We describe our experience in 10 patients in whom up to five electrode catheters and/or sheaths were placed through an IVC filter using a transfemoral approach under fluoroscopic guidance without routine venography. Devices were successfully introduced and withdrawn in each case without filter dislodgment. Our series illustrates the feasibility and safety of passing multiple electrode catheters and long sheaths through an IVC filter. Evidence is accumulating to suggest that an IVC filter should not be considered an absolute contraindication to performing diagnostic or therapeutic procedures.

Complete versus partial distal embolic protection during renal artery stenting.

OBJECTIVE: The aim of this study was to evaluate whether complete embolic protection is superior to partial embolic protection for preservation of kidney function during renal artery angioplasty and stenting. BACKGROUND: Renal artery angioplasty and stenting (RAAS) is a common treatment for atherosclerotic renal artery stenosis. However, RAAS may be complicated by peri-procedural loss of kidney function. METHODS: In total, 44 patients were randomized to embolic protection devices (EPD) use; 25 complete and 19 partial embolic protection. These patients were further randomized to receive abciximab (n = 23) or placebo (n = 21). [corrected] MDRD glomerular filtration rate (GFR), was used as the primary measure of renal function. Creatinine was measured by a modified Jaffe reaction using the IDMS-traceable assay. The primary endpoint was the percent change in estimated glomerular filtration rate (eGFR) 1 month following stent placement. RESULTS: There was no difference in percent change eGFR at 1 month between complete or partial protection (-4 +/- 25 vs. +3 +/- 30, P = 0.45). Abciximab was associated with a net improvement in eGFR when compared with placebo (+0.5 +/- 27 vs. -11 +/- 20, P = 0.04). On subgroup analysis, the use of abciximab was associated with significantly improved eGFR in the partial distal embolic protection group (+14 +/- 33 vs. -17 +/- 13 %, P = 0.018) but not in the complete distal embolic protection group (+2.5 +/- 26 vs. -11 +/- 24, P = 0.42), however, there was no interaction between completeness of protection and abciximab on eGFR (P = ns). Capture of embolic material was more likely with complete protection when compared with those receiving partial protection (51% vs. 21%, P < 0.05). CONCLUSION: Complete protection was superior to partial protection for the capture of athermanous debris during renal artery stenting. However, this was not associated with improved renal function. Importantly, Abciximab conferred a benefit for renal function that was independent of the degree of embolic protection.

Radiation-induced peripheral artery disease.

Radiation therapy is a cause of cardiovascular morbidity and mortality. This is due to the significant degree of atherosclerosis seen in the vessels in the vicinity of the area being irradiated. Radiation-induced peripheral arterial disease is increasingly being recognized as large populations of cancer patients survive longer, yet it is a problem that is often under reported. Although it has most commonly been associated with carotid artery disease, all vascular beds are prone to this form of injury. The injury is accelerated by usual risk factors for atherosclerosis. Developing a healthy lifestyle, dietary prudence and the aggressive treatment of hypertension, diabetes mellitus, and dyslipidemia should all be encouraged in this patient population. When revascularization strategies are warranted, the percutaneous approach may be superior to open surgery as technical difficulties may arise in the fibrotic, scarred tissue. Stenting with distal embolic protection devices should be considered as the treatment of choice for patients with radiation-induced carotid artery disease. Several reports also suggest good results with balloon angioplasty with or without stenting in the case of radiation-induced renal, iliac, and femoral artery disease. Lifelong antiplatelet therapy may be appropriate.

Quality of life improves after renal artery stenting.

Although treatment of renal artery stenosis (RAS) with stents has been shown to improve blood pressure (BP) and renal function in some patients, little is known about the effect on health-related quality of life. A composite quality of life survey was administered in a cross-sectional cohort fashion to 149 patients presenting with angiographically and hemodynamically confirmed RAS either before (baseline, n = 37) or after (follow-up, n = 112) stent revascularization. BP, renal function, and antihypertensive medication use were also assessed. Systolic BP was lower in the revascularized patients (166 +/- 23 vs. 153 +/- 26, p < .01). The Short Form-36 Physical Component Summary (PCS) scores were higher (better) in revascularized patients (37 +/- 9 vs. 31 +/- 9, p < .01), whereas Mental Component Summary scores were equivalent (49 +/- 13 vs. 51 +/- 11, p = ns). Sleep dysfunction scores were lower (better) in the revascularized patients (32 +/- 26 vs. 48 +/- 32, p < .001), whereas self-reported appetite was higher (better; 62% +/- 29% vs. 73% +/- 27%,p < .05). After matching for age and gender, Short Form-36 PCS remained higher in the revascularized cohort (37 +/- 8 vs. 32 +/- 8, p < .05). Importantly, in multivariate analysis, revascularization was the most significant determinant of a higher PCS score (r2 = .07, beta = 5.21, p < .01). The current data suggest that renal artery stenting may improve health-related quality of life in patients with renovascular disease.

Paclitaxel-eluting stents for the treatment of femoropopliteal arterial stenoses: focus on the Zilver PTX drug-eluting peripheral stent.

Restenosis is one of the major limitations of the percutaneous treatment of peripheral artery disease, leading to the need for repeat interventions, limb loss and increased cost of therapy. The current standard of percutaneous treatment of stenotic lesions in the femoropopliteal arterial segment includes balloon angioplasty and bare-metal stenting. Recently, research in the field adapting the coronary arterial bed treatment model led to the inclusion of antimitotic drugs in the form of drug-eluting stents to combat neointimal proliferation and reduce the burden of restenosis. Randomized trial and registry data emerged indicating improved long-term outcomes with drug-eluting stents in peripheral arteries, lending the way to more widespread adaptation of this modality in the management of patients with peripheral artery disease.

Renal insufficiency as a predictor of adverse events and mortality after renal artery stent placement.

BACKGROUND: Renal artery stenosis (RAS) is associated with substantial morbidity and mortality. This relationship is strongest in the presence of renal insufficiency (RI). The goal of this study is to assess the relationship between RI, mortality, and adverse events in the setting of renovascular disease. METHODS: Two hundred sixty-one patients with significant RAS treated with endovascular stenting were followed up prospectively for 21 +/- 18 months (range, 0 to 85 months). Blood pressure (BP), renal function, medication use, and comorbidities were assessed. Death was verified through the Social Security Death Master Index File, and cause of death was derived from death certificates. Medical records of 230 subjects subsequently were reviewed to identify adverse cardiovascular and renal events. RESULTS: Overall, 37% of patients experienced at least 1 adverse event postprocedure. Myocardial infarction (MI) and congestive heart failure (CHF) events increased with degree of baseline RI. Seventy-three deaths (28%) occurred postprocedure (range, 13 to 2,457 days). Baseline characteristics associated with mortality included advanced age, decreased use of beta-blockers, increased use of diuretics, increased serum creatinine (Cr) level, decreased Cr clearance (CrCl), bilateral stenoses or stenosis of a solitary kidney, history of CHF, and history of MI. Follow-up characteristics associated with mortality included lower systolic and diastolic BP, increased serum Cr level, and decreased CrCl. RI at baseline and follow-up remained associated with mortality after adjusting for other clinically and statistically significant variables. Patients in whom renal function improved after stenting appeared to show improved survival over those without improved renal function (45% versus 0% cumulative survival, P < 0.05). CONCLUSION: In patients with RAS undergoing stent therapy, baseline RI is associated with an increased incidence of adverse events, as well as decreased survival, independent of other baseline clinical factors. Importantly, improvement in renal function appears to be associated with increased survival.

Compliance with antihypertensive therapy after renal artery stenting.

Hypertension is an important clinical endpoint after renal artery revascularization for renal artery stenosis (RAS). Medication compliance is a critical determinant of blood pressure control. Although factors influencing compliance are known in essential hypertension, they have not been evaluated in studies investigating renal artery revascularization. The aim of this study was to assess the determinants of compliance to antihypertensive therapy in patients with RAS following renal artery stent placement (RASP). A cross-sectional study evaluating blood pressure, antihypertensive medications, quality of life, compliance, and determinants of compliance to antihypertensive therapy was undertaken in 112 patients undergoing RASP. Additionally, cardiovascular risk factors, antihypertensive medications, and cardiovascular history were reported. Self-reported compliance was 79% +/- 24% (scale of 0% [none] to 100% [complete] compliance) in patients after RASP. Determinants of compliance by multivariate analysis included physical symptoms, which correlated negatively to compliance and included loss of appetite (r2 = 0.26, P < 0.0001), dizziness (r2 = 0.06, P < 0.01), and cough (r2 = 0.03, P < 0.05). Systolic blood pressure correlated positively with compliance (r2 = 0.03, P < 0.05). The number or class of antihypertensive medications did not influence compliance. Patients' physical symptoms and level of systolic blood pressure, rather than the number or class of medications, influence compliance in patients with continued hypertension after RASP. Attention to physical symptoms may help to improve blood pressure control in this population.

Percutaneous coronary intervention through unintentional sheath placement in the inferior epigastric artery.

A 64 year old female underwent percutaneous coronary intervention (PCI) with stent placement through the femoral approach. On femoral angiography after the PCI, the arterial sheath insertion site was found to be in the inferior epigastric artery and not in the common femoral artery. We used an Angioseal vascular closure device for management and there were no access site complications.

A role for embolic protection in the management of acute limb ischemia.

Distal embolization is a complication during lower-extremity revascularization procedures that may occur when intervening on acute or subacute lesions. Several studies have demonstrated the safety and feasibility of using embolic protection devices (EPD) and some interventionalists have adapted this technology for use in infrainguinal revascularization procedures. At present, there are no randomized trials to indicate the benefit, safety, and cost-effectiveness of EPD for this application and its use in the United States is considered off-label. However, based on our experience and a review of the published literature, we consider the use of EPD in acute lower-extremity ischemia a reasonable strategy.

Platelet activation in patients with atherosclerotic renal artery stenosis undergoing stent revascularization.

BACKGROUND AND OBJECTIVES: Soluble CD40 ligand (sCD40L) is a marker of platelet activation; whether platelet activation occurs in the setting of renal artery stenosis and stenting is unknown. Additionally, the effect of embolic protection devices and glycoprotein IIb/IIIa inhibitors on platelet activation during renal artery intervention is unknown. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Plasma levels of sCD40L were measured in healthy controls, patients with atherosclerosis without renal stenosis, and patients with renal artery stenosis before, immediately after, and 24 hours after renal artery stenting. RESULTS: Soluble CD40L levels were higher in renal artery stenosis patients than normal controls (347.5 ± 27.0 versus 65.2 ± 1.4 pg/ml, P < 0.001), but were similar to patients with atherosclerosis without renal artery stenosis. Platelet-rich emboli were captured in 26% (9 of 35) of embolic protection device patients, and in these patients sCD40L was elevated before the procedure. Embolic protection device use was associated with a nonsignificant increase in sCD40L, whereas sCD40L declined with abciximab after the procedure (324.9 ± 42.5 versus 188.7 ± 31.0 pg/ml, P = 0.003) and at 24 hours. CONCLUSIONS: Atherosclerotic renal artery stenosis is associated with platelet activation, but this appears to be related to atherosclerosis, not renal artery stenosis specifically. Embolization of platelet-rich thrombi is common in renal artery stenting and is inhibited with abciximab.

Paclitaxel-eluting stents show superiority to balloon angioplasty and bare metal stents in femoropopliteal disease: twelve-month Zilver PTX randomized study results.

BACKGROUND: Sustained benefits of drug-eluting stents in femoropopliteal arteries have not been demonstrated. This prospective, multinational, randomized study was designed to compare the 12-month safety and effectiveness of a polymer-free, paclitaxel-coated nitinol drug-eluting stent (DES) with percutaneous transluminal angioplasty (PTA) and provisional bare metal stent (BMS) placement in patients with femoropopliteal peripheral artery disease. METHODS AND RESULTS: Patients were randomly assigned to primary DES implantation (n=236) or PTA (n=238). Demographics and lesion characteristics were similar between groups (eg, average lesion length, approximately 65±40 mm). One hundred twenty patients had acute PTA failure and underwent secondary random assignment to provisional DES (n=61) or BMS (n=59). Primary end points were the 12-month rates of event-free survival and patency in the primary DES and PTA groups. Compared with the PTA group, the primary DES group exhibited superior 12-month event-free survival (90.4% versus 82.6%; P=0.004) and primary patency (83.1% versus 32.8%; P<0.001), satisfying the primary hypotheses. In the secondary evaluations, (1) the primary DES group exhibited superior clinical benefit compared with the PTA group (88.3% versus 75.8%; P<0.001), (2) the provisional DES group exhibited superior primary patency (89.9% versus 73.0%; P=0.01) and superior clinical benefit (90.5% and 72.3%, P=0.009) compared with the provisional BMS group, and (3) the stent fracture rate (both DES and BMS) was 0.9% (4/457). CONCLUSIONS: Femoropopliteal peripheral artery disease treatment with the paclitaxel-eluting stent was associated with superior 12-month outcomes compared with PTA and provisional BMS placement.