Endovascular Treatment of Occlusive Lesions in the Aortic Bifurcation with Kissing Polytetrafluoroethylene-Covered Stents.

PURPOSE: To determine the clinical outcomes of polytetrafluoroethylene covered balloon expandable stents (CBESs) in occlusive lesions of the aortic bifurcation in a kissing stent configuration. MATERIALS AND METHODS: The study included 69 consecutive patients (29 men, 40 women) who underwent kissing stent procedures with CBESs between January 2003 and April 2009 in a single center. Patients who were previously treated with a CBES were excluded. Follow-up consisted of clinical investigation and duplex ultrasound examination. RESULTS: The primary patency was 88.1% at 1 year and 71.5% at 4 years, with secondary patency rates of 88.1% and 75.3%, respectively. For patients receiving a stent for the first time, primary patency was 91.3% at 1 year and 77.1% at 4 years. For patients who had received previous stents, patency was 83.6% at 1 year and 65.2% at 4 years (P = .83). There were no differences in secondary patency and freedom from target lesion reintervention (TLR). Loss of primary patency was mainly caused by stent occlusions (14 cases [78%]). The freedom from TLR at 4 years was 76.8%. CONCLUSIONS: Patency rates and freedom from TLR of CBESs in the kissing stent configuration with up to 4 years of follow-up were satisfying and mainly affected by stent occlusions. Studies focusing on optimizing stent configuration and medical care to reduce the incidence of thrombosis are indicated to improve results further.

Thrombogenicity and related biological properties of heparin bonded collagen coated polyester and human umbilical vein prosthetic vascular grafts.

BACKGROUND: Multiple factors contribute to the process of prosthetic graft failure. Some of them are specifically related to the biological behavior of the used materials. To pursue the ideal substitute for the autologous vein graft, many materials have been taken into consideration. Of these, polyester (Dacron) and human umbilical vein (HUV, Dardik) bypass grafts have gained much attention in vascular surgical practice over the years. This study compares the results of both in vivo and in vitro investigations on graft thrombogenicity and neo-intimal formation in collagen-coated heparin bonded Dacron and in HUV bypass grafts. It is an adjunct to our clinical comparison of graft materials in infrainguinal arterial reconstruction. METHODS: In 12 adult Beagle dogs, a patch was sewn onto the abdominal aorta (Dacron, n = 6; HUV, n = 6). At defined interval times, thrombocyte aggregation was measured with nuclear imaging of 99mTechnetium labeled platelets. Post-mortem histological analysis of the interface between the native vessel wall and the patch was performed in all animals. RESULTS: At 4 h (2.67, SD = 0.77) and after 2 weeks (2.21, SD = 0.28) after implantation, significantly higher thrombogenicity was measured in the HUV grafts compared to Dacron grafts (1.98, SD = 0.10 and 1.98, SD = 0.11, P = 0.02 and 0.025, respectively). At 4 weeks, no significant difference could be found (HUV, 2.26; SD = 0.29; Dacron, 2.11; SD = 0.16; P = 0.23). Measurement of 'neo-intimal' thickness after explantation of the patch at 28 days after the initial procedure showed a significant difference: in HUV grafts the mean thickness of the inner lining was 0.76 mm (SD = 0.50), compared to 0.16 mm (SD = 0.10) in the Dacron grafts (P = 0.013). CONCLUSION: HUV grafts showed a higher thrombogenicity at 4 h and 2 weeks after insertion of the graft compared to Dacron grafts. At 4 weeks this difference is not present. After 28 days the inner ('neo-intimal') lining is significantly more pronounced in HUV grafts than in Dacron grafts.

Assessment of prosthetic vascular graft thrombogenicity using the technetium-99m labeled glycoprotein IIb/IIIa receptor antagonist DMP444 in a dog model.

INTRODUCTION: Prosthetic graft patency greatly depends on graft thrombogenicity. The concept of graft thrombogenicity is poorly understood and difficult to measure or quantify. In a study we tested the experimental radiopharmaceutical DMP444 and developed a suitable dog model. This agent is a radiolabelled ((99m)Technetium) glycoprotein IIb/IIIa receptor antagonist with a high affinity for activated platelets. It binds to platelets that are intimately involved in thrombus formation. The agent does not affect thrombocyte function, when used in a dose necessary for imaging. DMP444 does not require platelet harvesting and processing. Early imaging of thrombocyte aggregation sites such as vascular prostheses is possible within 4 hours after injection. MATERIAL AND METHODS: Adult Beagle dogs weighing 12-15 kg were used for the experiments. In 16 dogs a prosthetic patch was sewn onto the abdominal aorta (Bovine pericard: n=4, Dacron: n=6, Human Umbilical Vein: n=6). Imaging cycles after injection of (99m)Technetium-labelled DMP444 were performed on days 1, 7, 14 and 28 after surgery. RESULTS: We noticed differences in thrombus formation on the tested graft materials. The bovine pericard patches (n=4) showed a relatively high rate of thrombocyte aggregation. In the Dacron patches (n=6) aggregation was not seen. In 1 of 6 cases of human umbilical vein patches a measurable focal aggregation was recorded. CONCLUSION: The method outlined in this study is a relatively simple and reproducable method to visualize thrombocyte aggregation.