PubMed · 3267429
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P Amalric. 1988. [Choroidal silence].. https://pubmed.ncbi.nlm.nih.gov/3267429/
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BACKGROUND: Current methods of angiography cannot provide images of arteries measuring < 200 microns in diameter. We have recently developed a new angiography system that uses monochromatic synchrotron radiation and a high-definition video system with a spatial resolution of 30 microns. In the present study, we applied this microangiography system to visualize small arteries in normal and ischemic rat limbs and investigated the development of collateral arteries. METHODS AND RESULTS: Microangiography was performed in the normal and the ischemic limb 4 weeks after the excision of the femoral artery. In the normal limb, up to the fourth branches of the iliac and/or femoral arteries (diameter < 100 microns) were readily identified. Some of these branches were found to perfuse the distal thigh area. In the ischemic limb, an extensive structural remodeling of the vascular network was observed. Numerous small arteries had developed from the branches of the iliac artery to constitute a fine arterial network, the so-called "midzone," which was composed of linear, normal appearing arteries and those with an undulating, unbranched appearance. CONCLUSIONS: The small collateral artery network was angiographically visualized with a resolution limit < 100 microns. The linear collaterals appeared to result from an opening of preexisting vessels. The undulating, unbranched vessels were not observed in the normal limbs and seemed to be vessels that were newly formed after limb ischemia. Synchrotron radiation microangiography appears to be a powerful means of assessing the development of small collateral arteries, which may help to provide a basis for understanding of the collateral circulation.
We describe successful treatment with intravascular stenting of a patient with spontaneous right carotid artery dissection. This case report demonstrates the potential use of stents for treating symptomatic carotid artery dissection.
BACKGROUND: Because prior studies have established the critical role of the endothelium in preventing vascular thrombosis and intimal thickening, we designed a series of experiments to determine the feasibility of percutaneous local catheter delivery of recombinant protein to accelerate development of an intact endothelial monolayer after stent implantation. METHODS AND RESULTS: Balloon injury followed by percutaneous delivery of a 15-mm-long, balloon-expandable metallic stent was performed in 64 rabbit external iliac arteries (baseline diameter, 2.67 +/- 0.07 mm). Planimetric time-course analysis disclosed < 20% stent endothelialization at 4 days, < 40% at 7 days, and near-complete endothelialization at 28 days. The reporter protein horseradish peroxidase and the endothelial cell-specific recombinant protein vascular endothelial growth factor (VEGF) were each effectively delivered from a local delivery catheter (channel balloon catheter, ChB) after stent implantation. Although local catheter delivery (of vehicle control) itself mildly retarded the extent of stent endothelialization (10.6 +/- 2.9%) versus no local delivery (25.5 +/- 6.6%, P = .045), local ChB delivery of 100 micrograms VEGF overcame this catheter effect: By day 7, stent endothelialization was nearly complete (91.8 +/- 3.8%) (P < .0001 versus no local delivery). Consequently, stent thrombus was reduced in the VEGF-treated group (mural thrombus, 5.3 +/- 3.7%) versus no local delivery (29.3 +/- 6.8%, P = .006). Occlusive thrombus was seen only in the absence of local VEGF administration. CONCLUSIONS: (1) Local delivery of recombinant protein to the arterial wall is feasible after stent implantation, and (2) local delivery of the endothelial cell mitogen VEGF accelerates stent endothelialization, reducing stent thrombosis. These results thus establish a novel means by which the safety and/or bioactivity of endovascular stents may be further enhanced.