Though initially used for central venous access in the placement of tunnelled catheters, vena cava filters, and TIPS, the authors have found the Site-Rite II dedicated vascular access ultrasound device to be useful for directing antegrade access to the superficial femoral artery. In this article, the Site-Rite’s ability to provide quick, simple access is further explored.
The Site-Rite II device (Dymax Corporation, Pittsburgh, PA) is a
dedicated vascular access ultrasound that is battery powered and
has interchangeable 7.5 and 9.5 MHz transducers (figure 1). At 7.5
MHz, the device has a maximum visualized depth of 4 cm. The
transducers are lightweight, fit easily into a small sterile field,
and have an attachment to which any of three disposable needle
guides can be attached over a sterile drape (figure 2). The guides
are configured with slightly different angles so that the depth at
which the needle crosses the visual field can be selected by
choosing the appropriate guide. Three color-coded guides are
provided in a single-use prep kit which additionally contains a
sterile sleeve and sterile coupling gel. The monitor also is quite
small and can easily be placed next to a procedure table. The
display includes a depth indicator, measured in 5 mm increments,
which is aligned along the center of the visualized field. When the
depth marker is activated, it provides an indication of the path
that the needle will follow. We initially used the device for
central venous access in the placement of tunnelled catheters, vena
cava filters, TIPS, and similar procedures. More recently, we have
found it useful for directing antegrade access to the superficial
femoral artery (SFA).
After routine consent and sterile preparation, the femoral
vasculature is delineated with a draped Site-Rite II ultrasound
transducer. The femoral bifurcation is identified in the transverse
plane, and the distal common femoral artery (CFA) depth is
determined using the distance scale on the image display (figure
3). Using this measurement, the appropriate needle guide is placed
on the transducer. With the transducer and attached needle guide
angled caudally, a micropuncture needle is directed into the distal
CFA under direct visualization (figure 4). When blood return is
noted, contrast is injected through the needle, and a roadmap image
is generated (figure 5). The micropuncture wire is then advanced
though the needle, using the roadmap and fluoroscopic guidance to
direct the wire into the SFA. The needle is then exchanged for the
micropuncture sheath/dilator assembly, after which an 0.038"
guidewire can be introduced and the micropuncture set exchanged for
a standard vascular access sheath.
In some cases, initial ultrasound evaluation will show the
femoral bifurcation to be above, or very close to, the inguinal
ligament. In these situations, we may elect to gain antegrade
access by direct micropuncture of the SFA. The profunda femoris
artery (PFA) can be avoided by using the Site-Rite for direct
visualization. After blood return and prior to placing a vascular
sheath, we obtain a roadmap image to verify that the PFA has not
been entered in error. Direct SFA puncture requires careful
consideration, as discussed in the following section.
Ultrasound guidance with the Site-Rite device is our standard
approach to antegrade access and has been used in 16 consecutive
patients at our institution. In 14 of these cases, the CFA was
entered first, followed by placement of a sheath into the SFA. The
other 2 patients underwent direct puncture of the SFA. We were
successful in establishing antegrade access to the SFA in all 16
cases, usually on the first attempt. No complications related to
the antegrade access have occurred.
Antegrade access facilitates lower extremity interventional
procedures in several ways. The need for "up-and-over"
catheterization of the aortic bifurcation is eliminated. As a
result, the distance to a given lesion is reduced by some 60 cm,
allowing the use of shorter catheters, wires, and other devices.
Manipulation of endovascular devices is enhanced both by their
shorter length and the mechanical advantage of a straighter course.
In addition, the operator is spared having to reach across the
Gaining antegrade access to the SFA is difficult because
reliable radiographic landmarks are absent. The usual technique is
to enter the ipsilateral common femoral artery (CFA) and
subsequently advance a wire into the SFA under fluoroscopic
observation. If the entry site is too high, intraperitoneal or
retroperitoneal hemorrhage can occur; an entry site that is too low
can cause femoral pseudoaneurysms and arteriovenous fistulae.1,2 In
either situation, the injury can be difficult to diagnose, and even
more difficult to treat, without surgical intervention.
Furthermore, successful entry into the CFA does not guarantee
success in advancing a guidewire into the SFA. Rather, the wire may
preferentially enter the profunda femoris, with possible injury to
a significant collateral bed.
Several techniques for direct puncture of the SFA have been
described. If diagnostic angiography has been performed from the
contralateral approach, a "target" wire or contrast injection
through the catheter can be used to localize the CFA or SFA for
puncture under direct fluoroscopic control.3 A similar approach may
be possible if the vessels are sufficiently calcified to allow
clear visualization without additional contrast. Other procedures
are required when no catheter is in place and calcification is
absent or insufficient for fluoroscopic identification. Kikkawa,4
Saddekni,5 and Saltzman6 all have used specially designed entry
needles or catheters, while Bishop7 has used a variable stiffness
guidewire. Blais described direct antegrade puncture of the SFA
using palpation alone.8 In his series, 25 consecutive antegrade
punctures were carried out, with only two minor complications. No
comment was made regarding the amount of time or number of passes
required to gain access. Still, his results demonstrate that
selective catheterization of the SFA may be safe. While each of
these techniques has been shown to be successful, they all require
a significant amount of manipulation, additional puncture sites, or
specialized equipment. The device that we describe, while
specialized for vascular access, can be used in any superficial
The use of ultrasound guidance for invasive procedures,
including vascular access, is well known. However, the "freehand"
technique most commonly employed can be cumbersome and time
consuming. Visualization of the needle tip frequently is poor,
especially when the target is superficial and near-field artifact
degrades image quality. By combining an integral needle guide with
depth and course indicators, the Site-Rite device eliminates the
need for continuous sonographic visualization of the needle as it
advances toward the vessel. The operator is able to align the depth
guide with the center of the vessel, and can simply advance the
needle tip until it appears as a bright echo within the relatively
hypoechoic vessel lumen. We have not recorded the actual time
required to gain vascular access using this technique, but we
believe it to be significantly less than that required for either
the freehand ultrasound technique or a puncture directed by
During the process that we described, it is useful to carefully
evaluate the vascular anatomy prior to attempts at needle placement
(figure 3). The femoral vein is medial to the artery and can be
compressed with manual pressure on the transducer. However, the
arteries are not as easily compressible. The SFA is anterior to the
profunda, and the two vessels can be followed caudally from the
bifurcation. The ideal entry site is distal to the inguinal
ligament and proximal to the bifurcation. We generally select a
site roughly 5 mm cranial to the point at which the SFA and PFA are
first seen as distinct structures. One should avoid an entry site
distal to the femoral head, however, as postprocedure hemostasis is
more easily achieved when the puncture site can be compressed
against the femoral head. As stated earlier, direct puncture into
the SFA may be safe when it is necessary to avoid the inguinal
ligament. This technique should not be considered the standard
approach, however, as the smaller diameter of the SFA may increase
the risk of vascular injury or of occlusion of the vessel by the
large catheters required for stent placement. Furthermore, direct
access to the SFA may limit the operator's ability to treat very
proximal SFA lesions.
During needle placement, the bevel should be pointing anteriorly
and the transducer should be angled caudally (figure 4). This
assures that the angle of entry will be shallow, reducing the risk
of posterior wall injury during guidewire placement and enhancing
the opportunity for selective SFA access. The needle guides are
designed for an 18 gauge needle. This occasionally causes some
difficulty when a micropuncture technique is used, as slight
lateral deviations of the 20 gauge needle within the guide can
cause it to miss a small vessel. If desired, one can use an 18
gauge needle followed by an 0.035" wire. We prefer micropuncture
technique, however, for the following reasons: l) the micropuncture
wire is highly torqueable, allowing subsequent selection of the
SFA; 2) the needle is relatively atraumatic, but is large enough to
allow a digital roadmap to be produced; 3) single-wall technique
can be used; and 4) there is no need for a dermotomy until stable
access has been achieved.
Regardless of the needle used to gain access, a roadmap should
always be generated prior to placement of a large catheter or
sheath. Despite direct visualization, it is possible that aberrant
anatomy or operator error could result in the profunda femoris
being entered instead of the CFA or SFA. In addition, a roadmap
image reduces the risk of dissection if the entry site is
immediately adjacent to an occult plaque or stenosis.
In summary, the technique that we describe provides quick,
simple antegrade access to the SFA while minimizing the risk of
complication. It has become our standard practice. The Site-Rite II
device, although expensive to purchase initially, also can be used
for numerous other types of peripheral and central vascular access.
1. Rapoport S, Sniderman KW, Morse SS, et al: Pseudoaneurysm: A
complication of faulty technique in femoral arterial puncture.
Radiology 154:529-530, 1985.
2. Lampmann LE, Leenen L: Hemorrhage due to laceration of an
aberrant inferior epigastric artery during femoropopliteal PTA in
an obese patient; a rare complication of a high antegrade femoral
puncture. Vasa 24(4):382-384, 1995.
3. Berman HL, Katz SG, Tihansky DP: Guided direct antegrade
puncture of the superficial femoral artery. AJR 147:632-634,
4. Kikkawa K: A new antegrade femoral artery catheter needle
set. Radiology 151:798, 1984.
5. Saddekni S, Srur M, Cohn DJ, et al: Antegrade catheterization
of the superficial femoral artery. Radiology 157:531-532, 1985.
6. Saltzman J. Probst P: A new puncture technique (Seldinger
technique) for easy antegrade catheterization of the superficial
femoral artery. Eur J Radiol 7:54-55, 1987.
7. Bishop AF, Berkman WA, Palagalla GL: Antegrade selective
catheterization of the superficial femoral artery using a
movable-core guidewire. Radiology 157:548, 1985.
8. Blais C: Antegrade puncture of the superficial femoral
artery: a pilot project. Can Assoc Radiol J 44(4):253-256,
Dr. Andrews and Dr. Osterman are with the Division of
Interventional Radiology at Johns Hopkins Medical Institutions in
Baltimore, MD. Dr. Andrews is currently with the Dotter
Interventional Institute at Oregon Health Sciences University in