Current state of endovascular treatment of femoro-popliteal artery disease

Single-Center Experience With Lutonix Drug-Coated Balloons in Infrapopliteal Arteries

Purpose: To examine patient outcomes following the use of the Lutonix drug-coated balloon (DCB) in patients undergoing endovascular intervention in below-the-knee (BTK) arteries. Methods: A retrospective chart review identified 248 patients who were treated for symptomatic peripheral artery disease with the Lutonix DCB between May 2013 and October 2014. Forty patients were lost to follow-up, leaving 208 patients (mean age 74.1±9.7 years; 138 men) with evaluable data for outcome analysis. The patient cohort suffered from either severe claudication (38.6%) or critical limb ischemia (CLI; 61.4%) in 220 limbs. Almost two-thirds (140, 63.6%) of the 220 target lesions were total occlusions, and 37 (17.8%) of all patients had occlusion of all 3 BTK vessels before intervention. Results: Over a median 9-month follow-up, target lesion revascularization occurred in 15.9% of patients with an average time to first reintervention of 8 months. In total, 39 amputations were performed in 31 limbs. However, 17 of these amputations were preplanned minor amputations below the ankle; only 9 (4.1%) major amputations occurred corresponding to 6.6% of the CLI cohort. Freedom from the composite of death or major amputation was estimated as 92% and 85% at 6 and 12 months, respectively, by Kaplan-Meier analysis. In the full cohort, improvement of at least 1 Rutherford category was seen in 130 (59.1%) limbs after 1 year or at the last follow-up, with 104 (80.0%) of those limbs showing an improvement of ≥2 categories. Conclusion: From this single-center experience, the Lutonix DCB shows therapeutic promise in a disease state where new treatment options are needed.

Endovascular intervention for peripheral artery disease

Advances in endovascular therapies during the past decade have broadened the options for treating peripheral vascular disease percutaneously. Endovascular treatment offers a lower risk alternative to open surgery in many patients with multiple comorbidities. Noninvasive physiological tests and arterial imaging precede an endovascular intervention and help localize the disease and plan the procedure. The timing and need for revascularization are broadly related to the 3 main clinical presentations of claudication, critical limb ischemia, and acute limb ischemia. Many patients with claudication can be treated by exercise and medical therapy. Endovascular procedures are considered when these fail to improve quality of life and function. In contrast, critical limb ischemia and acute limb ischemia threaten the limb and require more urgent revascularization. In general, endovascular treatments have greater long-term durability for aortoiliac disease than femoral popliteal disease. Infrapopliteal revascularization is generally reserved for critical and acute limb ischemia. Balloon angioplasty and stenting are the mainstays of endovascular therapy. New well-tested innovations include drug-eluting stents and drug-coated balloons. Adjunctive devices for crossing chronic total occlusions or debulking plaque with atherectomy are less rigorously studied and have niche roles. Patients receiving endovascular procedures need a structured surveillance plan for follow-up care. This includes intensive treatment of cardiovascular risk factors to prevent myocardial infarction and stroke, which are the main causes of death. Limb surveillance aims to identify restenosis and new disease beyond the intervened segments, both of which may jeopardize patency and lead to recurrent symptoms, functional impairment, or a threatened limb.

Pooled Analysis of the CONFIRM Registries

Purpose: To compare the acute procedure and angiographic outcomes of peripheral artery disease (PAD) patients treated with orbital atherectomy stratified by gender. Methods: The CONFIRM I, II, and III registries are US multicenter, nonrandomized, all-comers registries of PAD patients who were treated with orbital atherectomy. All patients with gender specified in the registry database were included in the current analysis, which compared the final residual stenosis achieved after atherectomy and the rate of acute complications in female and male patients. The 3 registries included 3131 patients with 4761 lesions: 1261 women (mean age 73.2±10.7 years) with 1874 lesions and 1870 men (mean age 70.4±10.2) with 2887 lesions. Results: The women were older (p<0.001) and had a higher but nonsignificant prevalence of critical limb ischemia (p=0.075). After treatment, the final residual stenosis in women vs. men was 9%±11% vs. 11%±11%, respectively (p<0.001). Women had a higher rate of all types of dissection (13.3% vs. 9.9%, p<0.001). However, both genders had similar rates of flow-limiting dissections (1.6% vs. 1.4%, p=0.61), perforation, slow flow, vessel closure, spasm, embolism, and thrombus formation. Conclusion: The gender analysis of the CONFIRM registries revealed that there was successful lesion modification with orbital atherectomy in both men and women; however, women had a higher rate of dissection (all types). This difference is likely because of the older age and higher percentage of critical limb ischemia in women in this cohort. These results, however, suggest that additional studies should be completed to further understand the increased risks for women vs. men during endovascular procedures.

Pooled analysis of the CONFIRM registries: safety outcomes in diabetic patients treated with orbital atherectomy for peripheral artery disease

PURPOSE

To compare the acute outcomes of orbital atherectomy treatment in diabetic vs. non-diabetic patients with peripheral artery disease (PAD).

METHODS

The CONFIRM registry series contained 1842 diabetic patients (1111 men; mean age 70.6±10.2 years) with 2819 lesions and 1247 non-diabetic patients (732 men; mean age 72.9±10.7 years) with 1885 lesions. The composite rate of procedure-related complications, including dissection, perforation, slow flow, vessel closure, spasm, embolism, and thrombus formation, was analyzed for the diabetic and non-diabetic groups.

RESULTS

Diabetics were younger but had a higher prevalence of coronary artery disease (p<0.001), renal disease (p<0.001), hypertension (p<0.001), hyperlipidemia (p<0.001), and lower ankle-brachial index scores (p=0.007). Diabetics had more severe PAD (Rutherford category 4-6; p<0.001), longer lesions (p<0.001), more infrapopliteal lesions (58% vs. 46%, p<0.001), and more lesions with severe and moderate calcium (86% vs. 78%, p<0.001). Diabetic and non-diabetic patients had the same (21.8%) composite rate of procedure-related complications, as well as similar rates of dissection (11.4% vs. 10.8%, p=0.68), embolism (2.2% vs. 2.4%, p=0.67), and thrombus formation (1.3% vs. 1.1%, p=0.75). However, diabetics had lower rates of perforation (0.5% vs. 1.1%, p=0.03) and spasm (5.5% vs. 7.6%, p=0.005), but a higher rate of slow flow (5.0% vs. 3.5%, p=0.02) and a tendency toward increased vessel closure (1.7% vs. 0.9%, p=0.06).

CONCLUSION

Plaque modification with orbital atherectomy resulted in similar low procedure-related complication rates in both the diabetic and non-diabetic groups, despite diabetics having more unfavorable baseline clinical and lesion characteristics. This study suggests that orbital atherectomy is a safe and effective treatment modality in both the diabetic and the non-diabetic populations.

Cilostazol increases patency and reduces adverse outcomes in percutaneous femoropopliteal revascularisation: a meta-analysis of randomised controlled trials

Background

Cilostazol is an oral antiplatelet agent currently indicated for treatment of intermittent claudication. There is evidence that cilostazol may reduce femoropopliteal restenosis after percutaneous endovascular intervention.

Methods

We searched PubMed, Scopus and Cochrane databases from 1966 through September 2013 for randomised controlled trials (RCTs) evaluating the addition of cilostazol to standard care in patients receiving femoropopliteal endovascular treatment. Restenosis, target lesion revascularisation and combined adverse outcomes (death, revascularisation and amputation) within 1–2 years postprocedure were evaluated.

Results

Of 205 articles, three RCTs were included in the analysis. The pooled data provided a total of 396 patients, 195 of whom received cilostazol. When compared to standard medical therapy alone, cilostazol significantly reduced the risk of restenosis (risk difference −0.20; 95% CI −0.29 to −0.11; p<0.0001; number needed to treat 5), target lesion revascularisation (risk difference −0.17; 95% CI −0.25 to −0.09; p<0.0001; number needed to treat 6). Death and amputation were not different in between groups.

Conclusions and limitation

Cilostazol significantly increases femoropopliteal patency and decreases adverse outcomes in percutaneous endovascular intervention. However, further RCTs are needed because of limited sample size; this meta-analysis represents the best current evidence.

Application of rotational atherectomy for a calcified superficial femoral artery lesion

A 78-year-old man on dialysis with a history of femoro-popliteal bypass grafting of his right superficial femoral artery was presented with a recurrence of intermittent claudication. Angiography revealed new heavily calcified stenosis located distal to the anastomosis of the graft. A guide wire was crossed the lesion, however, a balloon catheter could not pass. Rotational atherectomy with Rotablator enabled the balloon to cross the lesion with full dilatation. Due to residual stenosis and dissection, a stent was implanted. Final angiogram showed no residual stenosis with TIMI 3 flow. The patient remained free of symptoms during the 1-year follow-up.

Predictors of medium-term patency in percutaneous endovascular therapy of femoro-popliteal lesions

BACKGROUND

The objective is to study the medium-term results of angioplasty and stenting in the femoro-popliteal sector in patients with critical limb ischemia (CLI), and identify angiographic predictive factors of primary patency.

PATIENTS AND METHODS

Retrospective review of 98 patients with critical ischemia and angiographic lesions characterized as TASC A=13 (14%), B=38 (40%), C=24 (25%) or D=20 (21%). A total of 106 angioplasties and primary self-expanding stents (mean length of stent coverage of 19cm) were performed between January 2006 and January 2011.

RESULTS

The immediate results of patency, limb salvage and survival were 95, 96 and 96%, respectively. Primary patency at 1 and 2 years was 54 and 38%, respectively. Twenty-seven cases (25%) required endovascular iterative procedures, providing an assisted patency at 1 and 2 years of 72 and 60%, and a secondary patency of 80 and 67%. A lower primary patency was observed (log rank) when stent length was >20cm (P<.001), popliteal artery was invloved (P=.004), and in TASC C and D lesions (P=.04). In multivariate analysis (Cox), only stent length>20cm was an independent negative predictor for primary patency (HR=5.7, P<.001). The limb salvage at 1 and 2 years was 83 and 81%, respectively.

CONCLUSIONS

Angioplasty with stent in the femoro-popliteal sector is a safe technique, but with significantly lower permeability results in injuries that require stent coverage of more than 20cm. In these cases, vein bypass surgery should be the procedure of choice.

Fatigue behaviour of Nitinol peripheral stents: the role of plaque shape studied with computational structural analyses

Fatigue resistance of Nitinol stents implanted into femoro-popliteal arteries is a critical issue for the particular biomechanical environment of this district. Hip and knee joint movements due to the cyclic daily activity expose the superficial femoral artery (SFA), and therefore the implanted stents, to quite large and cyclic deformations influencing stent fatigue resistance. Objective of this work is to provide a tool based on finite element analysis able to evaluate the biomechanical effect of SFA on stent fatigue resistance. Computer simulations of the treatment of stenotic vessel by angioplasty and stenting and of the subsequent in vivo loading conditions (axial compression and bending) were carried out. Three different stenotic vessel models were defined, by keeping a constant stenosis rate and changing the plaque sharpness and number of stenoses. The fatigue behaviour was analysed comparing the amplitude and mean value distribution of the first principal strain in the whole stent for the different simulated conditions. Results showed that the maximum mean strain is similar in all the models, while the alternating strain is related to both plaque shape and loading conditions. In conclusion, this study confirms the requisite of replicating in vivo loading conditions. It also reveals the importance of taking into account the thickness variation of the vessel in the stenotic zone in the assessment of the stent fatigue resistance.

Transpopliteal balloon-assisted excimer-laser atherectomy for the treatment of chronic femoropopliteal occlusions: feasibility and initial results

PURPOSE

Recanalization of chronic total occlusions (CTOs) of the femoropopliteal arteries depends on a successful lesion crossing with the guide wire. The aim of this retrospective study was to evaluate the safety, feasibility, and the primary results of retrograde recanalization of CTOs with balloon-assisted excimer–laser atherectomy (ELA) via a transpopliteal approach after failed antegrade attempts.

METHODS

A total number of 15 patients (10 male, 5 female) with a mean age of 68.5 years (range: 43–91 years) treated with retrograde transpopliteal ELA in the years 2009–2012 were included retrospectively. After unsuccessful antegrade recanalization attempts with conventional guide wires and catheters, patients were treated with a retrograde recanalization attempt via a transpopliteal access using an excimer laser, followed by pressure-only balloon angioplasty (POBA). The mean length of the CTOs in the femoropopliteal arteries was 17.8 ± 5.4 cm (range: 9–29 cm).

RESULTS

Technically successful recanalization was achieved in 14 of 15 patients. Provisional stenting was done in two cases. There were no major adverse events regarding the laser atherectomy or popliteal access site. One acute reocclusion was observed in the first 48 hours after intervention. The ankle-brachial Index increased from preinterventional 0.45 ± 0.07 to 0.77 ± 0.29 (P < 0.05) in the follow-up period (1.5 months), resulting in a primary patency of 80%.

CONCLUSION

The retrograde ELA for recanalization of chronic femoropopliteal occlusions via a popliteal access turned out to be a safe and effective procedure with promising primary results. Thus it may be an endovascular treatment option for long chronic occlusions after failed antegrade recanalization or in patients who are not suitable for surgery.

Cilostazol Reduces Angiographic Restenosis After Endovascular Therapy for Femoropopliteal Lesions in the Sufficient Treatment of Peripheral Intervention by Cilostazol Study

Background—

It remains unclear whether cilostazol, which has been shown to improve the clinical outcomes of endovascular therapy for femoropopliteal lesions, also reduces angiographic restenosis.

Methods and Results—

The Sufficient Treatment of Peripheral Intervention by Cilostazol (STOP-IC) study investigated whether cilostazol reduces the 12-month angiographic restenosis rate after percutaneous transluminal angioplasty with provisional nitinol stenting for femoropopliteal lesions. Two hundred patients with femoropopliteal lesions treated from March 2009 to April 2011 at 13 cardiovascular centers were randomly assigned 1:1 to receive oral aspirin with or without cilostazol. The primary end point was 12-month angiographic restenosis rate. Secondary end points were the restenosis rate on duplex ultrasound, the rate of major adverse cardiac events, and target lesion event-free survival. Researchers evaluated all follow-up data and assessed the end points in a blinded fashion. The mean lesion length and reference vessel diameter at the treated segment were 128±86 mm and 5.4±1.4 mm, respectively. The frequency of stent used was similar between groups (88% versus 90% in the cilostazol and noncilostazol group, respectively, P =0.82). During the 12-month follow-up period, 11 patients died and 152 patients (80%) had evaluable angiographic data at 12 months. The angiographic restenosis rate at 12 months was 20% (15/75) in the cilostazol group versus 49% (38/77) in the noncilostazol group ( P =0.0001) by intention-to-treat analysis. The cilostazol group also had a significantly higher event-free survival at 12 months (83% versus 71%, P =0.02), although cardiovascular event rates were similar in both groups.

Conclusions—

Cilostazol reduced angiographic restenosis after percutaneous transluminal angioplasty with provisional nitinol stenting for femoropopliteal lesions.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT00912756; and URL: https://www.umin.ac.jp . Unique identifier: UMIN000002091.

Peripheral applications of drug-coated balloons: past, present and future

Drug-coated balloon (DCB) technologies represent the latest and hottest development in the field of endovascular treatment of peripheral arterial disease. Initial experience with paclitaxel-coated balloon use in the femoral artery has demonstrated lower mid-term restenosis and superior mid-term clinical outcomes in terms of improved wound healing and reduced repeat angioplasty rates compared with standard balloon angioplasty. Many companies are presently developing and/or improving DCB catheters and therefore ongoing, technical improvements of the already existing platforms, new drugs, and innovative carriers are expected. The ongoing basic research studies and various multicenter randomized, controlled trials that are currently in progress will offer valuable scientific insights regarding the long-term effectiveness and other crucial issues, such as efficacy in various vascular beds, optimal balloon dosage, and post angioplasty antiplatelet therapy. Future applications of these devices also could include in-stent restenosis, anastomotic stenosis of surgical bypass, and benign stenoses of the central venous system. The authors envision that DCB angioplasty will evolve to a major paradigm shift in the endovascular treatment of occlusive vascular diseases.

Multicenter, intra-individual comparison of single dose gadobenate dimeglumine and double dose gadopentetate dimeglumine for MR angiography of the peripheral arteries (the Peripheral VALUE Study)

PURPOSE

To prospectively compare single dose gadobenate dimeglumine with double dose gadopentetate dimeglumine for CE-MRA in patients with peripheral arterial occlusive disease (PAOD) using an intra-individual crossover study design in which all patients received both contrast agents in otherwise identical CE-MRA examinations.

MATERIALS AND METHODS

Institutional review board and regulatory approval were granted and all patients provided written informed consent. Sixty-eight patients (53M/15F; 62.4 ± 15.7 years) with mild-to-severe PAOD were enrolled for randomized 3-station CE-MRA with 0.1 mmol/kg gadobenate dimeglumine and 0.2 mmol/kg gadopentetate dimeglumine. Three blinded readers assessed images for vessel anatomical delineation, disease detection/exclusion, and global preference. Diagnostic performance for detection of ≥51% stenosis was determined for 53 patients who underwent DSA. Noninferiority was assessed using the Wilcoxon Signed Rank, McNemar, and Wald tests. Quantitative enhancement was compared.

RESULTS

No differences (P ≥ 0.25) were noted for any qualitative parameter at any station. Equivalence was reported in at least 62/64 patients (93.8% 3-reader agreement) for diagnostic preference. Superiority for gadobenate dimeglumine was reported by all readers for diagnostic performance (sensitivity: 80.4-88.0% versus 75.2-85.8%; specificity: 89.8-96.0% versus 88.7-94.8%; accuracy: 87.4-91.7% versus 84.9-90.6%; PPV: 84.0-92.8% versus 82.3-90.8%; NPV: 88.5-92.4% versus 85.7-91.1%). Quantitative enhancement was similar in the pelvis but significantly (P < 0.05) greater with gadobenate dimeglumine in the thigh for two readers.

CONCLUSION

Image quality and diagnostic performance on peripheral CE-MRA with 0.1 mmol/kg gadobenate dimeglumine is at least equivalent to that with 0.2 mmol/kg gadopentetate dimeglumine.

DISCOVER: Dutch Iliac Stent trial: COVERed balloon-expandable versus uncovered balloon-expandable stents in the common iliac artery: study protocol for a randomized controlled trial

BACKGROUND

Iliac artery atherosclerotic disease may cause intermittent claudication and critical limb ischemia. It can lead to serious complications such as infection, amputation and even death. Revascularization relieves symptoms and prevents these complications. Historically, open surgical repair, in the form of endarterectomy or bypass, was used. Over the last decade, endovascular repair has become the first choice of treatment for iliac arterial occlusive disease. No definitive consensus has emerged about the best endovascular strategy and which type of stent, if any, to use. However, in more advanced disease, that is, long or multiple stenoses or occlusions, literature is most supportive of primary stenting with a balloon-expandable stent in the common iliac artery (Jongkind V et al., J Vasc Surg 52:1376-1383,2010). Recently, a PTFE-covered balloon-expandable stent (Advanta V12, Atrium Medical Inc., Hudson, NH, USA) has been introduced for the iliac artery. Covering stents with PTFE has been shown to lead to less neo-intimal hyperplasia and this might lower restenosis rates (Dolmatch B et al. J Vasc Interv Radiol 18:527-534,2007, Marin ML et al. J Vasc Interv Radiol 7:651-656,1996, Virmani R et al. J Vasc Interv Radiol 10:445-456,1999). However, only one RCT, of mediocre quality has been published on this stent in the common iliac artery (Mwipatayi BP et al. J Vasc Surg 54:1561-1570,2011, Bekken JA et al. J Vasc Surg 55:1545-1546,2012). Our hypothesis is that covered balloon-expandable stents lead to better results when compared to uncovered balloon-expandable stents.

METHODS/DESIGN

This is a prospective, randomized, controlled, double-blind, multi-center trial. The study population consists of human volunteers aged over 18 years, with symptomatic advanced atherosclerotic disease of the common iliac artery, defined as stenoses longer than 3 cm and occlusions. A total of 174 patients will be included. The control group will undergo endovascular dilatation or revascularization of the common iliac artery, followed by placement of one or more uncovered balloon-expandable stents. The study group will undergo the same treatment, however one or more PTFE-covered balloon-expandable stents will be placed. When necessary, the aorta, external iliac artery, common femoral artery, superficial femoral artery and deep femoral artery will be treated, using the standard treatment. The primary endpoint is absence of binary restenosis rate. Secondary endpoints are reocclusion rate, target-lesion revascularization rate, clinical success, procedural success, hemodynamic success, major amputation rate, complication rate and mortality rate. Main study parameters are age, gender, relevant co-morbidity, and several patient, disease and procedure-related parameters.

TRIAL REGISTRATION

Dutch Trial Register, NTR3381.

Noninvasive management of the diabetic foot with critical limb ischemia: current options and future perspectives

Foot ulcers are a major complication in patients with diabetes mellitus and involve dramatic restrictions to quality of life and also lead to enormous socio-economical loss due to the high amputation rate. The poor and slow wound healing is often aggravated by the frequent comorbidity of foot ulcers with peripheral arterial disease, making the treatment of this condition even more complicated. While the local treatment of foot ulcers is mainly based on mechanical relief and prevention or treatment of infection, improving perfusion of the impaired tissue remains the major challenge in peripheral arterial disease. While focal arterial stenosis is the domain of interventional angioplasty or vascular surgery, patients with critical limb ischemia and lacking options for revascularization have a much worse prognosis, because current treatment options avoiding amputation are scarce. However, based on recent research efforts, there is rising hope for promising and more-effective therapeutic approaches for these patients. Here, we discuss the current improvements of established therapies aimed at an improvement of limb perfusion, as well as the development of novel cutting-edge therapies based on stem-cell technology. The experiences of a 'high-volume center' for treatment of diabetic foot syndrome with a current major amputation rate of 4% are discussed.

Oversizing and restenosis with self-expanding stents in iliofemoral arteries

PURPOSE

Uncoated self-expanding nitinol stents (NS) are commonly oversized in peripheral arteries. In current practice, 1-mm oversizing is recommended. Yet, oversizing of NS may be associated with increased restenosis. To provide further evidence, NS were implanted in porcine iliofemoral arteries with a stent-to-artery-ratio between 1.0 and 2.3. Besides conventional uncoated NS, a novel self-expanding NS with an antiproliferative titanium-nitride-oxide (TiNOX) coating was tested for safety and efficacy.

METHODS

Ten uncoated NS and six TiNOX-coated NS (5-6 mm) were implanted randomly in the iliofemoral artery of six mini-pigs. After implantation, quantitative angiography (QA) was performed for calculation of artery and minimal luminal diameter. Follow-up was performed by QA and histomorphometry after 5 months.

RESULTS

Stent migration, stent fracture, or thrombus formation were not observed. All stents were patent at follow-up. Based on the location of the stent (iliac/femoral) and the stent-to-artery-ratio, stent segments were divided into "normal-sized" (stent-to-artery-ratio < 1.4, n = 12) and "oversized" (stent-to-artery-ratio ≥ 1.4, n = 9). All stent segments expanded to their near nominal diameter during follow-up. Normal-sized stent segments increased their diameter by 6% and oversized segments by 29%. A significant correlation between oversizing and restenosis by both angiography and histomorphometry was observed. Restenosis rates were similar for uncoated NS and TiNOX-coated NS.

CONCLUSIONS

TiNOX-coated NS are as safe and effective as uncoated NS in the porcine iliofemoral artery. All stents further expand to near their nominal diameter during follow-up. Oversizing is linearly and positively correlated with neointimal proliferation and restenosis, which may not be reduced by TiNOX-coating.

WITHDRAWN: Rationale and Design of a Randomised Controlled Trial Comparing Stent-Protected Angioplasty with Bypass Surgery for Intermittent Claudication: The ABC Study

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Dose response to Paclitaxel-coated balloon catheters in the porcine coronary overstretch and stent implantation model

OBJECTIVE

There is little published information regarding the efficacy of paclitaxel-coated balloon catheters except for the iopromide-containing formulation, and less is known about the kind of toxicity at overdose. The aim of our study was to assess 2 different paclitaxel matrix formulations on angioplasty balloon catheters in vitro, with respect to pharmacokinetics, and efficacy and tolerance to determine the minimum effective dose and local toxicity at extremely high dose which is only achieved in experimental studies.

METHODS AND MATERIALS

Adherence of coatings was tested in vitro in dry state and during passage through hemostatic valves, guiding catheters, and blood. Drug release, transfer to the vessel wall during coronary angioplasty, inhibition of neointimal proliferation, and tolerance were investigated in swine. Efficacy and tolerance of balloons were examined for doses ranging from 1 to 9 μg/mm2 and 3 overlapping applications of balloons coated with 3 times the regular dose of 3 μg/mm2. Paclitaxel concentrations were determined by high performance liquid chromatography, efficacy and tolerance by vital signs, clinical observation, quantitative coronary angiography, and histomorphometry 4 weeks after implanting premounted bare stents in coronary arteries applying 1:1.2 overstretch.

RESULTS

Under worst-case conditions, drug loss on the way through the guiding catheter and blood was in the range of 30%. After inflation of balloons coated with the clinically tested dose of 3 μg/mm2 in a coronary artery about 10% of drug remained on balloons, 20% to 30% was taken up into the vessel wall (∼200 μg). Neointimal area on cross sections was 6.8 ± 2.2 mm2 (uncoated control); 3.1 ± 1.1 mm2 (iopromide-matrix) and 3.0 ± 0.5 mm2 (urea-matrix) at 1 μg/mm2; 2.0 ± 0.4 mm2 versus 1.7 ± 1.1 mm2 at 3 μg/mm2 with no further decrease at higher doses. Thrombotic occlusions were observed in 3 of 15 vessel segments treated with overlapping inflations of 3 high-dose balloons but without any signs of aneurysms.

CONCLUSION

In the animal model, 2 paclitaxel matrix formulations were similar in respect of uptake in the vessel wall, and effective already at a dose of 1 μg/mm2. Except thrombotic events for the intentionally excessive dose, paclitaxel-coated balloons were well tolerated in the animal model.

Endovascular nitinol stenting for long occlusive disease of the superficial femoral artery in critical limb ischemia: a single-center, mid-term result

BACKGROUND

The aim of the present study was to assess the mid-term patency rate of nitinol stent implantation in patients with long superficial femoral artery (SFA) stenosis or occlusion. This is a retrospective, single-center study.

METHODS

The data of 138 patients were retrospectively assessed in our center to determine the patency rate after nitinol stenting of the SFA.

MATERIALS

Data for 165 limbs from 138 patients were collected. Each limb showed a long lesion with a total occlusion of >10 cm and mean lesion length of 20.35 ± 9.46 cm (range, 10-32 cm). Nitinol self-expanding stent implantations were performed in each limb. A total of 258 stents were implanted into 165 limbs (average, 1.56 stents/limb). Each patient received clinical and ultrasound/computerized tomographic angiography/magnetic resonance angiography evaluations before the procedure and underwent clinical status evaluation and an ankle-brachial index test at discharge and at 12, 24, and 36 months thereafter.

RESULTS

The initial technical success rate of revascularization was 91.51% (151/163). During follow-up, nine patients died because of myocardial infarction, cerebral infarction, and pneumonia, and 14 patients were lost to follow-up. The mean follow-up period for 150 limbs from 124 patients was 25.46 months (range, 6-51). During follow-up, 19 in-stent restenoses and 15 occlusions were diagnosed. In all, 30 re-interventions were performed, including six balloon angioplasties, three secondary cutting balloon angioplasties, 10 restenting procedures, four bypass surgeries, two bone marrow stem cell transplantations, and five limb amputations. Analysis showed the primary patency rates at 12, 24, and 36 months were 92.4%, 78.3%, and 62.1%, respectively, and the overall assisted-primary patency rates were 94.4%, 84.6%, and 75.8%, respectively.

CONCLUSIONS

Nitinol self-expanding stent implantation seems to be a good choice for older patients with long SFA occlusions. Although the short- and mid-term patency results were good, more observations are needed to assess its long-term efficiency.

Compound C inhibits vascular smooth muscle cell proliferation and migration in an AMP-activated protein kinase-independent fashion

6-[4-(2-Piperidin-1-yl-ethoxy)-phenyl]-3-pyridin-4-yl-pyrazolo[1,5-a] pyrimidine (compound C) is a cell-permeable pyrrazolopyrimidine derivative that acts as a potent inhibitor of AMP-activated protein kinase (AMPK). Although compound C is often used to determine the role of AMPK in various physiological processes, it also evokes AMPK-independent actions. In the present study, we investigated whether compound C influences vascular smooth muscle cell (SMC) function through the AMPK pathway. Treatment of rat aortic SMCs with compound C (0.02-10 μM) inhibited vascular SMC proliferation and migration in a concentration-dependent fashion. These actions of compound C were not mimicked or affected by silencing AMPKα expression or infecting SMCs with an adenovirus expressing a dominant-negative mutant of AMPK. In contrast, the pharmacological activator of AMPK 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside inhibited the proliferation and migration of SMCs in a manner that was strictly dependent on AMPK activity. Flow cytometry experiments revealed that compound C arrested SMCs in the G(0)/G(1) phase of the cell cycle, and this was associated with a decrease in cyclin D1 and cyclin A protein expression and retinoblastoma protein phosphorylation and an increase in p21 protein expression. Finally, local perivascular delivery of compound C immediately after balloon injury of rat carotid arteries markedly attenuated neointima formation. These studies identify compound C as a novel AMPK-independent regulator of vascular SMC function that exerts inhibitory effects on SMC proliferation and migration and neointima formation after arterial injury. Compound C represents a potentially new therapeutic agent in treating and preventing occlusive vascular disease.

Orbital atherectomy for symptomatic lower extremity disease

BACKGROUND

Plaque-debulking technologies have been proposed as alternative treatment options for peripheral arterial disease. Orbital atherectomy (OA), using the DiamondBack360 device, has emerged as one promising modality.

METHODS

We evaluated the safety and efficacy of OA in the first 200 lesions treated at our institution. Patient demographics, clinical characteristics, and lesion and procedural variables were collected and analyzed. The primary safety endpoint was the 30-day major adverse events (MAE), including death, myocardial infarction, stroke, unplanned amputation, or target lesion revascularization. Other safety endpoints included access-site complications, occurrence of dissections, perforations, distal embolization, spasm, and hemolysis. The efficacy endpoints were procedural success, need for adjunctive therapy, and improvement in ankle-brachial index. Multivariate analysis was performed to find independent predictors of the safety endpoints.

RESULTS

One hundred seventeen (58.5%) lesions were femoral, 31 (15.5%) were popliteal, and 52 (26.0%) were tibial. The procedural success (residual stenosis ≤30%) was comparable between the femoral and tibial lesions (86.3% vs. 92.5%, P = 0.18), but significantly lower for the popliteal lesions when compared with femoral and tibial (64.7% vs. 86.3%, P = 0.058, and 64.7% vs. 92.5%, P = 0.007 respectively). MAE at 30-days occurred in 3 (2.2%) procedures, and major access-site complications also occurred in 3 (2.2%). There were 31 (15.5%) dissections; independent predictors were diabetes mellitus (OR: 7.3, P = 0.008), crown-to-RVD ratio <0.6 (OR: 11.6, P = 0.005), and atherectomy time >360 sec (OR: 11.8, P = 0.001). There were 2 (1.0%) distal embolizations, 6 (3.0%) arterial spasms, and no perforations. Laboratory evidence of hemolysis was noted in 33.8% of cases.

CONCLUSION

Orbital atherectomy allows for a significant procedural success, limited need for stenting, and favorable safety profile.

Relevance of Mesh Dimension Optimization, Geometry Simplification and Discretization Accuracy in the Study of Mechanical Behaviour of Bare Metal Stents

In this paper, a set of analyses on the deployment of coronary stents by using a nonlinear finite element method is proposed. The author proposes a convergence test able to select the appropriate mesh dimension and a methodology to perform the simplification of structures composed of cyclically repeated units to reduce the number of degree of freedom and the analysis run time. A systematic study, based on the analysis of seven meshes for each model, is performed, gradually reducing the element dimension. In addition, geometric models are simplified considering symmetries; adequate boundary conditions are applied and verified based on the results obtained from analysis of the whole model.

A Novel Technology for Large Vessel Recanalization

Large vessels recanalization is a challenge for mechanical atherectomy devices, where the lumen debulked is close in diameter to the device crossing profile, which may be only 25% to 30% of the original lumen size; so, the procedure can restore only a fraction of the original blood flow. Moreover, small diameter lumens are prone to be repeatedly occluded after a relatively short period of time. In this article, we present a novel technology of recanalization, using a catheter-based microjet system to deliver a flux of biocompatible abrasive particles to the lesion site, resulting in microchipping of the plaque, while minimizing trauma to the vessel wall. Plaque debris is removed from the blood flow, and blood flow is restored. In contrast to rotating mechanical devices, plaque debulking can be performed up to diameters that are substantially larger than the device crossing profile, supporting superior long-term patency. As a case study, we evaluated the technology for use in the superficial femoral artery where the lesions tend to be very long and heavily calcified with high restenosis rates.

Bypass versus Angioplasty in Severe Ischaemia of the Leg (BASIL) trial: An intention-to-treat analysis of amputation-free and overall survival in patients randomized to a bypass surgery-first or a balloon angioplasty-first revascularization strategy

BACKGROUND

A 2005 interim analysis of the Bypass versus Angioplasty in Severe Ischaemia of the Leg (BASIL) trial showed that in patients with severe lower limb ischemia (SLI; rest pain, ulceration, gangrene) due to infrainguinal disease, bypass surgery (BSX)-first and balloon angioplasty (BAP)-first revascularization strategies led to similar short-term clinical outcomes, although BSX was about one-third more expensive and morbidity was higher. We have monitored patients for a further 2.5 years and now report a final intention-to-treat (ITT) analysis of amputation-free survival (AFS) and overall survival (OS).

METHODS

Of 452 enrolled patients in 27 United Kingdom hospitals, 228 were randomized to a BSX-first and 224 to a BAP-first revascularization strategy. All patients were monitored for 3 years and more than half for >5 years.

RESULTS

At the end of follow-up, 250 patients were dead (56%), 168 (38%) were alive without amputation, and 30 (7%) were alive with amputation. Four were lost to follow-up. AFS and OS did not differ between randomized treatments during the follow-up. For those patients surviving 2 years from randomization, however, BSX-first revascularization was associated with a reduced hazard ratio (HR) for subsequent AFS of 0.85 (95% confidence interval [CI], 0.5-1.07; P = .108) and for subsequent OS of 0.61 (95% CI, 0.50-0.75; P = .009) in an adjusted, time-dependent Cox proportional hazards model. For those patients who survived for 2 years after randomization, initial randomization to a BSX-first revascularization strategy was associated with an increase in subsequent restricted mean overall survival of 7.3 months (95% CI, 1.2-13.4 months, P = .02) and an increase in restricted mean AFS of 5.9 months (95% CI, 0.2-12.0 months, P = .06) during the subsequent mean follow-up of 3.1 years (range, 1-5.7 years).

CONCLUSIONS

Overall, there was no significant difference in AFS or OS between the two strategies. However, for those patients who survived for at least 2 years after randomization, a BSX-first revascularization strategy was associated with a significant increase in subsequent OS and a trend towards improved AFS.

[New stent developments for peripheral arterial occlusive disease]

Infrainguinal peripheral occlusive disease is increasingly being treated by endovascular techniques. Bare metal stainless steel, self-expanding nitinol stents, drug-eluting and covered stents (stent grafts) are becoming increasingly more important adjuncts to percutaneous translumninal angioplasty in the treatment of peripheral artery disease. In this article the available evidence supporting the use of stents in the femoropopliteal and tibial arteries will be described as well as their limitations. Future stent developments will also be discussed.

Percutaneous treatment of central venous stenosis in hemodialysis patients: long-term outcomes

The purpose of this study was to evaluate the long-term outcomes of endovascular treatment of central venous stenosis in patients with arteriovenous fistulas (AVFs) for hemodialysis. Five hundred sixty-three patients with AVFs who were referred for a fistulogram were enrolled in this study. Among them, 44 patients showed stenosis (n = 35) or occlusions (n = 9) in the central vein. For the initial treatment, 26 patients underwent percutaneous transluminal angioplasty (PTA) and 15 patients underwent stent placements. Periods between AVF formation and first intervention ranged from 3 to 144 months. Each patient was followed for 14 to 60 months. Procedures were successful in 41 of 44 patients (93.2%). Primary patency rates for PTA at 12 and 36 months were 52.1% and 20.0%, and assisted primary patency rates were 77.8% and 33.3%, respectively. Primary patency rates for stent at 12 and 36 months were 46.7% and 6.7%, and assisted primary patency rates were 60.0% and 20.0%, respectively. Fifteen of 26 patients with PTAs underwent repeated interventions because of restenosis. Fourteen of 15 patients with a stent underwent repeated interventions because of restenosis and combined migration (n = 1) and shortening (n = 6) of the first stent. There was no significant difference in patency between PTAs and stent placement (p > 0.05). Average AVF patency duration was 61.8 months and average number of endovascular treatments was 2.12. In conclusion, endovascular treatments of central venous stenosis could lengthen the available period of AVFs. There was no significant difference in patency between PTAs and stent placement.