[Percutaneous diagnostic angioscopy. Primary lesions].

Efficacy of percutaneous treatments of arterial affections requires the correct choice of indications, necessitating precise knowledge of elementary arterial lesions. Arterial endoscopy appears to be more specific than angiography for this use, since it allows direct vision in vivo of the lesion, a histopathologic approach compared with the non univocal images produced by angiography (for example, an arterial obstruction can result from varied causes). Different accidents to the endothelial surface can be observed: golden yellow atheromatous elevations on a straw yellow background, intimal flaps, mobile intra-luminal vegetations. Established atheromatous stenosis are smooth and regular, or on the contrary ulcerated and edged with irregular flaps capable of provoking an eccentric residual lumen. The vegetating atheromatous lesions may project into the lumen, often as calcified and thus pearly white scales adhering to the wall, or as larger occlusive lesions. When capable of being isolated, a thrombus often completes the stenosis: its recognition is therefore fundamental since its removal exposes the subjacent lesions to be treated. The fresh clot is coral shaped, bright red and mobile in the blood flow. Established clots are compact and greenish brown. At an advanced stage of atheroma the surface of the occluding clot is covered with a regular straw yellow endothelium. In the presence of a dissecting vessel the fibroscope may be introduced into the false channel, no longer showing typical endothelium but a coagulated mass interspersed with fibrous bands. Prosthetic stenosis result from either intimal hyperplasia or a suturing fault with plication.