Development of a new intravascular low-profile device for exclusion of aortic aneurysm: an experimental pilot study.

PURPOSE: To present a new intravascular device for the treatment of aorto-iliac aneurysms. METHODS: This new device was tested in five dogs with abdominal aortic aneurysm created experimentally by over-dilation of a balloon-expandable stent with a 16 or 18 mm wide PTA balloon catheter. The design of the device is based on a self-expanding aortic stent which consists of two stretchable circular frames filled with a textile Dacron mesh membrane that is suspended horizontally into the infrarenal abdominal aorta proximally to the aneurysm. The frames are part of a preshaped double helical structure that is introduced longitudinally through a catheter in a parallel fashion and forming the desired shape at the vessel site to be occluded. Two iliac stent-grafts are introduced in a low-profile status through the membrane sealing the aneurysm sac and holding the stent-grafts in place. After stent-graft expansion, a new bifurcation located more proximally than the natural one is created. The follow-up of the dogs was performed clinically and angiographically, and specimens were evaluated histomorphologically. RESULTS: The membrane device can be introduced through a 9 Fr vascular sheath. Technical success was achieved in four of five dogs. Nine of ten stent-grafts could be fixed securely within the membrane, thus preventing dislocation. Aneurysms were excluded immediately, and blood flow to the external iliac arteries was restored by the stent-grafts. At 6-9 months follow-up of technically successful implanted devices, there were no endoleaks, no migration, no stenoses at contact sites between the implant material and vascular wall, and no stenosis or occlusion of the stent-grafts. At microscopic evaluation, the interspace between the membranes was filled with thrombotic material, thus ensuring exclusion of the aneurysm. CONCLUSION: This new device was found to be flexible, low profile and useful in excluding abdominal aortic aneurysm in the experimental setting.

Clopidogrel plus long-term aspirin after femoro-popliteal stenting. The CLAFS project: 1- and 2-year results.

The aim of this study was to determine the patency rate after femoro-popliteal stenting followed by oral clopidogrel plus long-term aspirin. In a prospective trial, 31 patients with a total of 33 femoro-popliteal artery lesions (21 stenoses, 12 occlusions; 24 femoral, 9 popliteal) were treated with flexible tantalum stents after unsuccessful percutaneous transluminal angioplasty (PTA) preceded by local fibrinolysis in 5 of 12 patients with total occlusion. Post-interventionally, oral aspirin 100 mg was started simultaneously for the long term and was combined with an oral loading dose of 300 mg clopidogrel, followed by 75 mg clopidogrel daily for 28 days. Patients were followed for at least 12 months (maximum 34 months) by clinical examination, Doppler pressure measurement, color and duplex sonography, and angiography in case of suspicion of restenosis. In a retrospective analysis, the results were compared with those of historical groups of patients having received aspirin only (41 patients) or a long-term high-dose low molecular weight heparin (LMWH)+aspirin treatment (42 patients). Three small puncture aneurysms were treated successfully by conservative means and were categorized as minor bleeding complication. Cumulative primary patency rate (PPR) was 76 +/- 7.5% (1 year), and 70 +/- 9.6% (2 years) in the clopidogrel+aspirin group, thus being tendentiously better than in the aspirin-only group showing 75 +/- 4.6% (1 year), and 50 +/- 8.1% (2 years). Long-term high-dose LMWH+aspirin treatment showed 87 +/- 5.8% (1 year), and 72 +/- 9.1% (2 years), thus being superior to the other treatment regimes, with a statistically significant difference (p<0.05) between the LMWH+aspirin and the aspirin group. Clopidogrel plus aspirin is a safe medication regimen and may be effective in the prevention of early stent thrombosis. Mid- and long-term patency rate seems to be intermediate as compared with other therapeutic regimens. The LMWH+aspirin seems to be superior compared with CLAFS; however, randomized studies with larger patient numbers are recommended.

First experimental results with a new type of stent: the double-coil device.

PURPOSE: To introduce a new stent design and evaluate its technical properties. METHODS: This stent consists of two nitinol wires partially connected to each other. After delivery through a catheter a tube-like helical stent forms within the artery. After experimental tests in flow models regarding mechanical properties, introduction and delivery technique, 15 stents were implanted into iliac, femoral, and carotid arteries of seven dogs. After 3-12 weeks angiographic follow-up stents were explanted for microscopic examination. RESULTS: Stents with expanded diameters of 5-10 mm can be introduced through a 5 Fr catheter with 0.038 inch luminal diameter. Thrombotic vessel occlusion was observed in one iliac artery after incorrect stent placement with diameter mismatch. Fourteen of 15 stents remained patent and revealed minor intimal hyperplasia in the areas of the stent strut connection points as well as some reduction in medial thickness. CONCLUSION: This new stent design has a small introduction diameter which is independent of the expanded diameter. The stent's principal characteristics may serve as a basis for further special developments.

Preliminary experience with locoregional intraarterial chemotherapy of uterine cervical or endometrial cancer using the peripheral implantable port system (PIPS): a feasibility study.

The purpose of this study was to assess the suitability of a percutaneously implantable catheter port system (PIPS) for repeated intraarterial locoregional chemotherapy (ILC) for cervical and endometrial carcinoma. In 30 patients with advanced, recurrent, or high-risk cervical (n = 23) or endometrial (n = 7) carcinoma, PIPS for ILC was implanted via a femoral access, the catheter localized in the infrarenal abdominal aorta. Chemotherapy was performed adjuvantly after surgery (n = 14) or neo-adjuvantly to enable surgery, or for palliation (n = 16). Port implantation, catheter placement, and repeated port puncture was uneventful in all patients. Complications included catheter dislocation (n = 1), catheter thrombosis (n = 2), subcutaneous infection (n = 1), port-bed skin atrophy (n = 1), requiring port explantation in 3 patients. At 2 years follow-up, complete remission was observed in 7/14 patients with adjuvant chemotherapy, partial remission in 3/14. Successful down-staging could be achieved in 4/8 patients with neo-adjuvant chemotherapy. The PIPS is suitable for repeated ILC which may be a valuable method for pre- and post-surgical therapy of advanced or high-risk cervical and endometrial cancer, for adjuvant chemotherapy as well as neo-adjuvantly for down-staging, or for palliation.