Interventional Cardiology. Группа авторов
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Femoral access
Anatomy
A good understanding of some key features of the local anatomy is essential for both optimal access and ideal management of the puncture site. Careful attention to access and careful evaluation of the access site are fundamental to reduce sheath insertion trauma and lead to uncomplicated sheath removal and the safe use of vascular closure devices.
It is important to puncture at the level of the common femoral artery. This allows compression of the vessel against the femoral head at the time of sheath removal. Punctures below the common femoral arterial bifurcation (hence in the profunda femoris or the superficial femoral artery) are over soft tissue and are difficult to compress (Figures 2.1 and 2.2). Such punctures have been shown to be associated with increased risk of pseudoaneurysms and arteriovenous fistula formation [5,6]. Punctures above the inguinal ligament (hence in the external iliac artery) are in the retroperitoneal space which also represents an incompressible space. Such high punctures are associated with increased risk of retroperitoneal bleeding [6–8].
Figure 2.1 Femoral artery angiogram taken after sheath insertion. The sheath has been inserted into the superficial femoral artery (SFA). The profunda femoris or deep femoral artery is labeled PF. The sheath terminates in the common femoral artery (CFA). The arrow denotes the lower margin of the curve of the deep circumflex iliac artery. This lower border of the curve courses along the inguinal ligament. Punctures above this landmark are usually adjacent to the retroperitoneal space and poses a high risk for bleeding complications.
Figure 2.2 Bilateral femoral artery angiograms. On the left panel, a line is drawn through the level of the mid femoral head. This is normally an ideal location for puncture. In this case, however, the femoral artery bifurcation is above the mid femoral head and the sheath can be seen entering the deep femoral artery. The right panel shows the left femoral angiogram. A line is drawn at the level of the top of the femoral head, showing a remarkably high bifurcation in this patient. Even though the sheath insertion on this side is just below the top of the femoral head, it is also in the deep femoral artery. Although this puncture is compressible over the femoral head, the branch is relatively smaller than the common femoral artery and less well suited for use of closure devices.
Landmarks on fluoroscopy are useful for identifying the position of the common femoral artery. About 75–80% of the common femoral bifurcation is at or below the inferior border of the femoral head and 95% is at or below the mid femoral head [5,9]. While the inguinal ligament is not visualized under fluoroscopy, the deep circumflex iliac artery is commonly used as a surrogate marker of the upper border of the common femoral artery because it is the last arterial branch of the external iliac artery before the external iliac courses under the inguinal ligament and becomes the common femoral artery (Figure 2.1). The deep circumflex iliac artery arises from the lateral aspect of the external iliac artery nearly opposite the origin of the inferior epigastric artery. It ascends obliquely laterally behind the inguinal ligament, contained in a fibrous sheath formed by the junction of the transversalis fascia and iliac fascia, to the anterior superior iliac spine. Puncture above the most inferior border of the course of the deep circumflex iliac artery has been associated with increased risk of retroperitoneal hemorrhage. This landmark is above the most superior border of the acetabulum in most patients [6].
Puncture technique
The basic technique of arterial access has changed very little since it was initially introduced by Seldinger [10]. Puncture of the common femoral artery is basically unchanged, save that the original concept used a through and through puncture and withdrawal of needle into the arterial lumen, while our current approach ideally punctures only the anterior surface of the femoral artery.
However, the technique can be substantially improved by using fluoroscopy of bony landmarks to identify the likely course of the common femoral artery followed by confirmation with femoral angiography after sheath insertion [11]. A point of entry into the common femoral artery at the mid femoral head or slightly above is ideal. The femoral skin crease, which is a very commonly used landmark for puncture, is distal to the common femoral bifurcation in 72% of cases [12]. Generally speaking, younger patients have a mid‐femoral head location relatively close or slightly above the femoral crease. Older patients have a femoral head significantly above the femoral crease, since the crease tends to sag with age. Obese patients may have two or sometimes even three femoral creases.
The technique of puncture requires multiple small steps to be optimized. Before local anesthesia is given, a clamp or needle can be laid at the point where the pulse is most easily felt, just above the femoral crease. Fluoroscopy can be used to locate the position of the needle relative to the center of the femoral head (Figure 2.3). Local anesthesia can thus be given accordingly. The needle should be aimed towards the artery at an angle of approximately 45o, avoiding too vertical or acute angles between the needle and the skin plane that can create too vertical or too long paths within the subcutaneous tissue complicating large bore sheath insertion and subsequent closure. After local anesthesia is given, the needle is advanced in the direction of the artery using palpation as a guide. At this point, it is useful to fluoroscope the location of the needle once again. This is the last chance to adjust the puncture to enter the common femoral artery in the ideal landing zone. This method is not often adhered to, but in the long run is very worthwhile and justifies the few seconds of extra time at the beginning of the procedure. Meanwhile, this is also the time to observe the behavior of the needle that is placed close to the femoral artery. If the needle is moving up and down, it is indirect evidence of puncturing the anterior wall of the common femoral artery. However, if the needle is moving side to side, it is indirect evidence of puncturing the lateral or medial side of the common femoral artery. Small adjustments of the angle of attack to the femoral artery are possible but an overzealous needle direction adjustment may result in a tortuous skin track. If the operator realizes that the direction towards the artery is grossly inaccurate, we suggest to restart from the skin level instead of having later to deal with resistance to the introduction of sheaths and closure devices due to the pinched subcutaneous tissue. Especially in obese patients the risk of wire kinking is not negligible. A smaller (4 or 5 Fr) short sheath can be used first advancing a catheter up to the aortic arch over a conventional soft wire, switching at that point