Ví dụ, bệnh nhân bị đau chân exertional rằng đôi khi bắt đầu ở phần còn lại có tăng tỷ lệ suy giảm chức năng so với các bệnh nhân PAD khác. Đánh dấu sự suy giảm chức năng là quan sát thấy ngay cả ở những bệnh nhân PAD không có triệu chứng so với người không có PAD | CHAPTER 21 Catheters and Diagnostic Angiography The pressure tolerance and volume injection thresholds of each catheter should never be exceeded during a power injection Image angulation that may assist in defining ostial disease in non-selective angiography Great vessels aortic arch LAO Renal arteries LAO for most patients Mesenteric vessels lateral view to steep RAO Internal iliac ostium contralateral oblique Common femoral bifurcation ipsilateral oblique The angiographer must understand the potential satellite non-vascular issues when interpreting the results of non-selective angiography Selective Angiography For the purpose of this discussion selective angiography is defined as the direct injection of contrast material in a preformed catheter positioned under fluoroscopic guidance into a target vessel. Several principles are fundamental to selective angiography. - First a selective catheter should never be advanced forward without being led by a guidewire. - Second hemodynamic assessment at the tip of the catheter should be performed before any forward injection of contrast or saline to avoid inadvertent injection of clot from the catheter tip barotrauma to the vessel wall athe-roembolism or vessel dissection. - Third gentle movement of the catheter is important to allow torque to be transmitted to the distal tip. Torque response is determined by catheter polymer characteristics and the presence or absence of a braid. - Fourth polymer-based hydrophilic catheters markedly improve tracking and can be essential for access of a contralateral limb in a patient with a steep aortoiliac bifurcation or distal aortoiliac tortuosity. In regions of the vascular tree with substantial vessel overlap or eclipsed by a metal prosthesis a clear understanding of the anatomy in a 3-dimensional plane is important to profile the vessels correctly and to obtain definitive diagnostic information. The anatomy can vary significantly from patient to patient so there is no definitive menu
