Drug-coated balloons in the lower limb.

Even if recently the first positive results were presented for a paclitaxel releasing drug eluting stent there are still concerns about stent implantation in the femoro-popliteal artery. This makes any stentless technology attractive that achieves at least as good acute and longer term results in this vessel area. Three randomized studies investigating the value of short time paclitaxel release using a drug coated balloon gave promising results with significantly improved patency rates compared to plain balloon angioplasty in femoro-popliteal lesions and at least as good patency results as for the majority of bare metal nitinol stents (THUNDER, FEMPAC, LEVANT 1). Below-the-knee this promising concept is still under evaluation (PICCOLO study) whereas the first positive results for drug eluting stents in shorter lesions had been recently presented (YUKON BTK, DESTINY). This article gives an overview upon already published and presented data and still ongoing trials on drug releasing balloons in the peripheral arteries.

The potential role of DES in peripheral in-stent restenosis.

In-stent restenosis (ISR) after non-coronary interventions is becoming an increasing clinical and technical problem in daily practice due to the more liberal use of stents particularly in femoro-popliteal and infra-popliteal interventions. Whereas in the coronaries the role of drug eluting stents (DES) in the treatment of ISR is already well defined, very limited data exist about the use of DES in the treatment of ISR in non-coronary arteries. So far little data is published on the potential role of DES in in-stent restenosis except in renal artery interventions. The concept of DES in femoro-popliteal lesions even excluding ISR so far failed for sirolimus and everolimus eluting self-expanding stents. In infra-popliteal lesions promising single centre reports have already been published. Own single center reports showed favorable patency rates for the treatment of renal artery ISR. So far, only one study - the Zilver(R) PTX(R) single arm study - investigates in a subcohort of 120 of 818 lesions the outcome of a paclitaxel eluting DES in treating ISR in femoro-popliteal arteries. The Zilver(R) PTX(R) stent consists of a self-expanding nitinol stent platform with a polymer free paclitaxel coating with a dose density of 3 mg/mm2. In an interim analysis the freedom from target lesion revascularization is 78% after one year. Even if not yet having data for primary and secondary patency available, these results compare favorably with alternative treatment options such as plain balloon angioplasty and cutting balloon angioplasty or even directional atherectomy. No data have been published or presented yet about the treatment of infra-popliteal ISR. Randomized comparative trials comparing dedicated DES with standard interventional techniques such as plain old balloon angioplasty for the treatment of ISR in femoro-popliteal and infra-popliteal ISR are mandatory.

Drug eluting stents versus PTA with GP IIb/IIIa blockade below the knee in patients with current ulcers--The BELOW Study.

The study was designed as a feasibility trial to evaluate the use of GP IIb/IIIa blockade in connection with drug eluting stents, bare stents and PTA only. Sixty patients with current ulcers were randomly assigned to receive abciximab plus a sirolimus coated stent (N.=14), abciximab plus a bare stent (N.=16), abciximab plus PTA (N.=14) and PTA alone (N.=19). Angiographic control was performed at two and six months. Recanalization was successful in all cases. Two month restenosis rate was 9%, 45.5%, 67% and 46%. At six month follow-up restenosis rate was 9%, 67%, 75% and 58%, respectively; 14% of all patients had major amputations within six months. Adjunctive administration of abciximab during peripheral arterial intervention below the knee was found to be safe. Sirolimus coated stent administration was followed by a higher patency rate.

Advances on drug-coated balloons.

During the last decades considerable advances have been made in intravascular interventions for the treatment of coronary and peripheral arterial disease. However, long-term outcome remains an area of concern in many applications. Restenosis is still a challenge in endovascular medicine and has thus been referred to as the Achilles' heel of percutaneous intervention. Therefore, novel strategies have been developed to overcome this problem. These include drug-eluting stents, though still associated with stent thrombosis and in-stent restenosis, and the more recently introduced non-stent based local drug delivery systems, especially the paclitaxel-eluting balloon. Results of several preclinical and clinical studies indicate that short-term exposure of injured arteries to paclitaxel eluted from regular PTA and PTCA balloons may be sufficient to reduce late lumen loss and restenosis rates during a critical period of time after angioplasty of diseased coronary and peripheral arteries. Although the number of published trials and patients treated is still limited, available data seem to prove that restenosis inhibition by immediate drug release is feasible. This article reviews the rationale for the use of paclitaxel-coated balloons, data from preclinical and clinical studies, and the perspective of drug-coated balloons in peripheral arterial disease.

[New stent developments for peripheral arterial occlusive disease]. / Neue Stententwicklungen für die periphere arterielle Verschlusskrankheit.

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.

Treatment of acute limb ischemia with focus on endovascular techniques.

Acute limb ischemia is still the most frequent cause of major limb loss. Timely and fast revascularization is the key for limb salvage and patient survival. Large randomized trials showed equivalency of surgical and endovascular revascularization by means of local lysis with urokinase (TOPAS, STILE). New lytic agents and their modified application such as via a pulse spray catheter or combined with an ultrasound catheter and the combination with glycoprotein IIb/IIIa receptor antagonists have increased the efficacy and speed of thrombolysis. Recently, mechanical thrombectomy devices have become more widespread because intervention time and bleeding complications can be reduced. This review article summarizes the clinical presentation of and the treatment options for acute arterial occlusive disease caused either by embolism or local thrombosis.

Endovascular repair of infrarenal abdominal aortic aneurysm associated with a horseshoe kidney and graft thrombosis in early follow-up.

Endovascular aneurysm repair (EVAR) is a well-established alternative to open surgery. The presented case underwent endovascular therapy of an abdominal aortic aneurysm (AAA) with the anatomical prerequisite of a horseshoe kidney. We describe the technique used, including the embolization of aortic side branches, to avoid endoleaks, and the management of thrombotic complications during follow-up.

[Unusual reason for unilateral (corrected) Raynaud's phenomenon with intensification when the arms are elevated]. / Einseitiges Raynaud-Phänomen mit Verstärkung bei Elevation des Arms.

Thoracic outlet syndrome (TOS) is a broad term for compression of the neurovascular structures in the area of the 1. rib and the clavicle. The cause can be either fibrous bands, cervical ribs, anomalous muscles or posttraumatic changes as well as tumors. Symptoms depend on the affected structure, in most cases (up to 97% of TOS patients) neurologic symptoms are present. In case of an arterial compression, for example due to a cervical rib like in our case, embolism of the arm and finger arteries can occur. For mild or moderate symptoms a conservative approach with physiotherapy can be helpful. For severe cases surgical resection of the compressing structure and the first rib is necessary. In our case, the cervical and first rib were excised after an initial lysis therapy. Furthermore, the aneurysm of the subclavian artery was excised.

Percutaneous vascular interventions in the superficial femoral artery. A review.

The superficial femoral artery (SFA) is a frequent target of atherosclerotic disease predominantly in the proximal section near the bifurcation to the deep femoral artery and in the distal section where the adductor muscles tend to compress the artery. In the past, SFA revascularization was the domain of vascular surgery (femoropopliteal and femorodistal bypasses). However, with the development of endovascular treatment and advancing techniques as well as more sophisticated stenting material and balloons, endovascular treatment is nowadays not just a treatment option but, in most cases, preferable at least as initial revascularization procedure in the treatment of peripheral artery vascular disease. In the last years, many efforts have been made to fight restenosis in revascularized artery segments after stenting and/or angioplasty. This article aims to give a review on this topic including the most recent experience with the various latest revascularization techniques such as drug eluting stents, coated stent grafts, brachytherapy, cryoplasty, cutting balloons, and drug coated balloons.

Drug coated stents for carotid intervention.

Carotid endarterectomy has demonstrated its superiority over medical treatment of symptomatic as well as asymptomatic stenosis of the extracranial carotid artery. Although minimally invasive methods initially failed to produce similar results, stent implantation is becoming an alternative technique for stroke prophylaxis with technical advances, cerebral protection and careful patient selection. Even though restenosis does not seem to be a major limitation compared to coronary interventions, in-stent restenosis might occur more frequently with an increasing number of procedures performed and longer follow-up periods. Drug eluting stents have shown to attenuate this complication. Currently, no clinical data on drug eluting stents in carotid arteries are available. This article discusses the current literature on carotid artery stenting and the potential role of drug eluting stents in this field.

[Radiofrequency ablation of liver metastases]. / Radiofrequenzablation von Lebermetastasen.

The liver is the second only to lymph nodes as the most common site of metastatic disease irrespective of the primary tumor. Up to 50% of all patients with malignant diseases will develop liver metastases with a significant morbidity and mortality. Although the surgical resection leads to an improvement of the survival time, only approximately 20% of the patients are eligible for surgical intervention. Radiofrequency (RF) ablation represents one of the most important alternatives as well as complementary methods for the therapy of liver metastases. RF ablation can lead in a selected patient group to a palliation or to an increased life expectancy. RF ablation appears either safer (vs. cryotherapy) or easier (vs. laser) or more effective (percutaneous ethanol instillation [PEI], transarterial chemoembolisation [TACE]) in comparison with other minimal invasive procedures. RF ablation can be performed percutaneously, laparoscopically or intraoperatively and may be combined with chemotherapy as well as with surgical resection. Permanent technical improvements of RF systems, a better understanding of the underlying electrophysiological principles and an interdisciplinary approach will lead to a prognosis improvement in patients with liver metastases.

[Microvascular denudation of the femoral artery of the mouse as a model for restenosis]. / Mikrovaskuläre Denudation der Arteria femoralis der Maus--ein Restenosemodell für die Experimentelle Radiologie.

OBJECTIVE: To present technique and results of a microvascular denudation of the common femoral artery of the mouse as a model for inducing intimal hyperplasia in interventional radiology. MATERIALS AND METHODS: Under general anesthesia introduced by intraperitoneal injection, 14 B6129F1 hybrid mice (7 females and 7 males) at a mean age of 12.1 +/- 1.8 weeks and a mean weight of 28 +/- 2.8 grams had a groin incision of the vascular bundle directly distal to the inguinal ligament in preparation of placing a vascular clamp. Thereafter, the femoral artery was dissected distal to the origin of the epigastric artery and a loop prepared for a ligation proximal to the planned arteriotomy. Through an arteriotomy performed free-hand with a pair of micro scissors, a 0.010" (= 0.25 mm) guidewire was introduced into the vessel and advanced to the aortic bifurcation. The guide-wire was moved back and forth three times. The same procedure was performed on the other side as sham-operation, i.e., without introduction and passage of a guidewire. The resulting changes of the vessel wall were evaluated by histology and morphometry. RESULTS: Four weeks after intervention, the mean intima-to-media-ratio (IMR) was 1.80 +/- 0.28. A significant difference was observed between the sexes, with an IMR of 1.41 +/- 0.29 in females and an IMR of 2.24 +/- 0.45 in males (p = 0.0173). The neointima led to an overall luminal loss of 50.2% +/- 8.3% without significant sex difference (p = 0.09), but the average luminal loss was still more severe in females, amounting to 43.9% in comparison to 56.1% in males. This technique induces a significant neointima formation in a reproducible manner. The internal elastic membrane was preserved in all vessels. CONCLUSION: This technique is an excellent model to examine the differences between genetically modified mice to clarify the role of putative key molecules in the pathophysiology of restenosis.

Radiopaque markers in endovascular stents--benefit and potential hazards.

AIM: The primary objective of this study was to evaluate the impact of radiopaque markers on stent visibility. The secondary objective was to investigate the impact of such radiopaque markers on localized corrosion at the stent corpus-marker interfaces. MATERIAL AND METHODS: The radiopacity of the following stents was evaluated at different fluoroscopy modes (spotfilm, continuous fluoroscopy, 15 p/s, 7.5 p/s, 3 p/s): Memotherm Flexx (FX), Memotherm Luminexx (LX)(Bard), SMART (SM), SMARTeR (SMR)(Cordis). Four readers evaluated a total of 3200 images (160 per stent per fluoro mode) according to the following radiopacity score (RS): 0 = no stent visible, 1 = poor, 2 = acceptable, 3 = good, and 4 = very good stent visibility. LX and SMR stents (n = 5/group) were subjected to potentiodynamic polarization testing in de-aerated Hanks salt solution at 37 degrees C using a potentiostat. Palmaz-Schatz stents (n = 3) were used as the control group for comparative evaluation. The corrosion current density (I corr ) and the breakdown value (E bd ) were compared parameters of interest. RESULTS: At the spotfilm mode the LX, the SM and the SMR were rated well to very well visible in 99 %, 96 %, 96 %, and the FX only in 64 %. At 7.5 p/s (standard fluoro mode) the LX was considered to be well to very well visible in 77 %, followed by the SMR in 12.5 %, the SM in 1 %, and the FX in 0 %. The SMR stents exhibited the highest E bd values (802 +/- 112 mV vs SCE), while the LX stents exhibited the lowest E bd values (155 +/- 38 mV vs SCE). Also, the average E bd values for the SMR stents were better than those exhibited by the PS stents (503 +/- 107 mV vs SCE). CONCLUSION: Stent radiopacity can be increased significantly with the help of radiopaque markers (p < 0,0001 LX vs. FX). However, the surface condition of the stent corpus and the mode of attachment of the marker onto the corpus may have a significant impact on the uniformity of the final corrosion behavior. It is not feasible to determine the clinical impact of this localized corrosion behavior from this in vitro study. Further experimentation is recommended to ascertain the same.

[Endovascular implantation of stent-grafts in the thoracic aorta -mid-term results of a prospective controlled study]. / Endovaskuläre Implantation von Stent-Grafts in die Aorta thoracica - Mittelfristige Ergebnisse einerprospektiven kontrollierten Studie.

PURPOSE: To evaluate the effectiveness and safety of endovascular treatment of various descending thoracic aortic pathologies with covered stent-grafts as an alternative to open surgery. METHODS: Among 16 patients (5 type B dissections, 5 contained ruptures, 3 aneurysms of the descending aorta, 1 thoraco-abdominal aneurysm, 1 mural thrombosis, 1 patch aneurysm) treated between November 1997 and November 2000, eight patients received Talent stent-grafts and another 8 patients underwent a Gore-TAG stent-graft implantation. A clinical follow-up and control CT scans were obtained after the procedure and then at six-month intervals. RESULTS: Deployment of the stent-grafts was technically successful in all cases. Sufficient aortic reconstruction was achieved in all but one patient who needed surgical treatment. One patient died two days after the procedure from aortic rupture due to retrograde type A dissection. Another patient died 19 months after the procedure from an unknown cause. There was no occurrence of distal embolization, paralysis or infection. During follow-up, all patients remained free from recurrence or late complications of their disease. CONCLUSION: Endoluminal treatment of thoracic aortic pathologies with covered stent-grafts appears to be a safe and feasible method with at least mid-term efficacy.

Peripheral artery occlusion: treatment with abciximab plus urokinase versus with urokinase alone--a randomized pilot trial (the PROMPT Study). Platelet Receptor Antibodies in Order to Manage Peripheral Artery Thrombosis.

PURPOSE: To evaluate the combination of a platelet glycoprotein IIb/IIIa complex receptor inhibitor and urokinase for treatment of recent (

Prophylaxis of restenosis with (186)re-labeled stents in a rabbit model.

BACKGROUND: Intraluminal beta-irradiation has been shown to decrease neointimal proliferation after angioplasty in experimental models. The purpose of this study was to test the technical feasibility and biological effects of (186)Re-labeled stents. METHODS AND RESULTS: Thirty-four New Zealand White rabbits were fed a 0.5% cholesterol diet before balloon angioplasty and insertion of Palmaz stents in the infrarenal aorta. The animals were killed 7 weeks after stent implantation. Two of 34 animals died prematurely (aortic leak, pneumonia). Control stents (n=7) were compared with (186)Re stents (2.6 MBq [n=6], 8.1 MBq [n=5], 16.0 MBq [n=6], and 25.3 MBq [n=8]). Stent application was successful in all cases. No thrombus occlusion was observed. After 7 weeks, neointima formation was 2.2+/-0.2 mm(2) in the control group. In the treatment groups, a dose-dependent neointima reduction was detectable (0.5+/-0.5 mm(2) [2.6 MBq], 0.4+/-0.4 mm(2) [8.1 MBq], and 0 mm(2) [16.0 MBq, 25.3 MBq]). No induction of neointimal formation was observed at the edges of the stents. Radiation resulted in delayed reendothelialization. CONCLUSIONS: (186)Re stents were capable of reducing neointima formation in a dose-dependent fashion. (186)Re stents did not cause late thrombosis or neointimal induction at the stent margins in the observation period of 7 weeks.

Tc-99m-labeled endothelin derivative for imaging of experimentally induced atherosclerosis.

OBJECTIVE: to characterize the potential of an endothelin derivative labeled with technetium-99m (Tc-99m) for the imaging of experimentally induced atherosclerosis. METHODS: neointima of different cellularity and severity of stenosis was induced in 32 rabbits by balloon denudation followed by distinct dietary regimens and drug application. Angiograms and scintigrams after injection of the Tc-99m-labeled endothelin derivative were obtained. The aorta was dissected for autoradiography, sudan-III-staining, morphometry, and immunohistology. RESULTS: the lesions induced could be detected in vivo (whole body scintigram) in all the animals 15 min after the injection of the Tc-99m endothelin derivative. Autoradiography revealed a strong relationship between tracer accumulation and sudan-III-staining of lesions. Accumulation of the endothelin derivative correlated with the number of neointimal smooth muscle cells (SMC), but not with the number of medial SMC, neointimal macrophages, and neointimal area. CONCLUSIONS: the results indicate that in vivo imaging of atherosclerosis with an endothelin derivative is a feasible method of detecting and characterizing atherosclerotic arterial wall lesions at early stages.

New strategies in platelet inhibition in noncoronary interventions.

Thrombembolic complications frequently occur during and after endovascular procedures because of associated arterial injury and thrombotic characteristics of implanted devices such as stents. New strategies in platelet aggregation inhibition are now available blocking the final and common pathway of platelet aggregation, the glycoprotein IIb/IIIa receptor. This treatment modality seems to be more effective for prophylaxis and prevention of thrombembolic complications than standard antiplatelet therapy. Most of the data provided for glycoprotein IIb/IIIa receptor blockade are derived from studies of coronary interventions. This report reviews the pharmacodynamic differences of classic and new drugs for platelet inhibition and the basic considerations for antiplatelet therapy in noncoronary interventions.

A new device for percutaneous suture-mediated closure of arterial puncture sites using exteriorized needles: initial experience.

PURPOSE: To assess the feasibility and initial clinical results of Closer (Perclose, Redwood City, California), a new device for percutaneous suture-mediated closure of arterial puncture sites. METHODS: Vascular interventions were performed using 6 and 7 French sheaths in 22 consecutive patients. All patients underwent suture-mediated percutaneous closure with the new device. Patients were followed by physical examination the day after the procedure. RESULTS: Immediate hemostasis was achieved in 20/22 patients (91%). In 3 out of 5 antegrade closures, only one suture was captured. In two cases, this was managed by reinsertion of a second device. In another patient, hemostasis was not achieved by the device due to knot entrapment. No major complications were observed. The overall rate of minor complications was 9% (2/22) due to hematomas without the need for blood transfusions. CONCLUSION: Percutaneous suture with this new device is an acceptably safe and effective method to achieve immediate hemostasis of the arterial access site after interventional procedures with minimized manipulation of the puncture track.