4.1
Choosing access site
Obtaining arterial access is required for performing diagnostic coronary angiography and percutaneous coronary intervention (PCI).
There is continued controversy about optimal access site selection. Radial (proximal or distal) or ulnar access is associated with significantly fewer access site complications and greater patient satisfaction compared with femoral access , but engaging the coronary arteries can be more challenging and guide catheter support may be suboptimal (due to more respiratory motion, subclavian tortuosity, or inability to insert large guide catheters in some patients). Brachial or other access sites, such as transcaval or carotid, are rarely used in clinical practice except for structural heart interventions. Developing expertise in both radial and femoral access is essential for the contemporary interventional cardiologist. The 2018 ESC guidelines state that “Radial access is preferred for any PCI irrespective of clinical presentation, unless there are overriding procedural considerations” .
The following algorithm ( Fig. 4.1 ) is recommended for access site selection, assuming expertise in both radial and femoral access:
Step 1 . Review prior history, physical examination, noninvasive tests, reports, and films from prior cardiac catheterization procedures. In some patients some access sites are not available or are not suitable for performing cardiac catheterization. Examples include patients with prior radial artery harvesting, occlusion of the common femoral or iliac artery or distal abdominal aorta, extreme iliac or subclavian artery tortuosity, inability to engage the coronary arteries during prior procedures, or dialysis shunts in the ipsilateral arm. Some patients may have a strong preference for a particular access site (e.g., some music players prefer not to use radial, as do some patients who use a walker, whereas the opposite is true for patients who are unable to lie on their back, such as patients with severe back pain or congestive heart failure).
Step 2 . If both radial and femoral access are an option, femoral access is usually preferred in patients with prior coronary artery bypass grafting (CABG) (with patent grafts) given increased technical difficulty engaging the grafts via radial access . If radial access is chosen, left radial is preferred to facilitate engagement of the left internal mammary artery (LIMA) graft, which nearly all patients have. If bilateral internal mammary grafts have been used, femoral access is strongly favored.
Step 3 . Use of radial access has been associated with lower mortality in ST-segment elevation acute myocardial infarction (STEMI) patients in several, but not all, studies, likely because of use of aggressive anticoagulation and antiplatelet regimens that increase the risk of bleeding.
Similarly, radial access is preferred in patients who are receiving oral anticoagulants (warfarin or direct oral anticoagulants) or are at high risk for bleeding (such as patients with high or low body mass index, renal failure, anemia, or thrombocytopenia) .
Step 4 . In cases of complex PCI (such as chronic total occlusions, severe calcification and tortuosity, challenging bifurcations, etc.) at least one femoral access (often with a 7 or 8 French sheath, ideally 45 cm long) is often preferred, as it usually provides better support and may improve the efficiency, success, and safety of the procedure. Long (45 cm) sheaths are often used for such procedures.
Step 5 . If the initially selected access site is subsequently shown to be suboptimal (failure to advance a wire or catheter to the aortic root, failure to engage the coronary arteries, failure to complete PCI), change to other access sites may facilitate success . However, obtaining femoral access in an anticoagulated patients (radial-to-femoral crossover) has been associated with increased risk of bleeding and should be done with extreme care using meticulous technique .
4.2
Femoral access
The following sequence is recommended for obtaining femoral access. It uses both fluoroscopy and ultrasound guidance and a micropuncture kit. While there is no definitive proof that use of micropuncture needle (21 gauge, outside diameter: 0.82 mm) is superior to use of a standard needle (18 gauge, outside diameter: 1.27 mm), use of a micropuncture needle is likely to cause less arterial injury ( Fig. 4.2 ). It also allows reattempting the stick (if the initial stick is felt to be suboptimal: too high or too low) without causing significant bleeding. Special caution should be paid to monitoring the position of the 0.018 in. guidewire (that comes with the micropuncture kit) position, as it may be more likely to enter side branches (such as the inferior epigastric artery or lateral circumflex iliac artery) and lead to perforation as compared with a 0.035 in. guidewire . The ideal location for femoral artery puncture depends on the location of the femoral bifurcation.
4.2.1
Step 1. Palpation of the femoral pulse
4.2.1.1
Goals
- 1.
To confirm the presence and location of a femoral pulse.
4.2.1.2
( Fig. 4.3 )
- 1.
Right common femoral artery: The operator places his or her left thumb on the right anterior superior iliac spine and the left middle finger on the pubic symphysis. The left second finger of the operator (index finger) should be located over the right common femoral artery above the right femoral head.
Figure 4.3
Palpation for identifying the optimal location for femoral artery puncture.
- 2.
Left common femoral artery: The operator places his or her left thumb on the pubic symphysis and the left middle finger on the left anterior superior iliac spine. The left second finger of the operator (index finger) should be located over the left common femoral artery above the left femoral head.
4.2.1.3
Challenges
- 1.
If the femoral pulse cannot be palpated or is weak, ultrasound should be performed to confirm the presence of a patent femoral artery and its size.
4.2.2
Step 2. Sterile preparation and draping of the groin
4.2.2.1
Goal
To clean the access site and reduce the risk of access site infection.
4.2.2.2
How?
- 1.
The groin areas (ideally both in case there is difficulty in obtaining access in the initially selected groin) are shaved.
- 2.
The groin areas are scrubbed with antiseptic solution, which should be applied from the center (side of puncture) to the periphery making concentric circles, to keep the center sterile.
- 3.
After the antiseptic solution dries up (to allow the adhesive tape to stick), the sterile drape is placed, centering its openings to the groin areas.
4.2.2.3
Challenges
- 1.
In very obese patients it may be challenging to reach the optimal access location due to subcutaneous fat. Taping the pannus may be useful in such cases. There are also specialized disposable systems for pannus retention, such as the Pannus retention system (TZ Medical, Portland, OR).
4.2.2.4
What can go wrong?
- 1.
The groin area can be contaminated (e.g., by the patient’s hands). If this happens, scrubbing with antiseptic solution should be repeated.
- 2.
The opening of the drape is positioned too high/low or too lateral/medial. The solution is to reposition the drape, after ensuring that the skin in the new area has been adequately prepared with antiseptic solution.
4.2.3
Step 3. Fluoroscopy of the femoral head
4.2.3.1
Goal
To identify the portion of the femoral artery located above the femoral head. Obtaining access over the femoral head (actually over the pubic bone) is optimal because it facilitates pressing the femoral artery against a hard surface (bone), helping achieve hemostasis after sheath removal. Higher arterial puncture (above the femoral head and above the origin of the inferior epigastric artery) is associated with higher risk of retroperitoneal bleeding. Lower puncture (below the femoral head) is associated with higher risk for pseudoaneurysm ( Section 29.1.3 ) and arteriovenous fistula ( Section 29.1.4 ) formation.
4.2.3.2
How?
- 1.
A hemostat, scissors or other metallic object is placed over the anticipated location of the femoral artery and the femoral head ( Fig. 4.4 ).
Figure 4.4
A hemostat is placed over the area of femoral pulse.
- 2.
Fluoroscopy in the AP projection is performed and the hemostat is repositioned until its tip is located at the inferior border of the femoral head ( Figs. 4.5 and 4.6 ).
Figure 4.5
Fluoroscopy of the hemostat to determine its location relative to the femoral head.
Figure 4.6
Localization of the inferior border of the femoral head by fluoroscopy using a hemostat (A). The hemostat position may need to be adjusted if it is too high or too low (B).
- 3.
Using a sterile marker, a line is drawn on the skin at the inferior border of the femoral head ( Fig. 4.7 ). Alternatively a micropuncture needle can be inserted as a marker of the inferior border of the femoral head.
Figure 4.7
Marking the location of the inferior border of the femoral head after fluoroscopy is performed.
4.2.3.3
Challenges
- 1.
In very obese patients the femoral head may be located under significant abdominal fat. In such cases pushing the overlying tissue up from the femoral crease is preferable than obtaining access through multiple tissue layers.
4.2.3.4
What can go wrong?
- 1.
Do not X-ray the operator’s hands! All operator body parts should be removed from the fluoroscopy beam area.
- 2.
Significant anatomical variations exist in the location of the common femoral artery bifurcation. Fluoroscopy alone may not be accurate in identifying the bifurcation of the common femoral artery into the profunda and superficial femoral artery, highlighting the importance of ultrasound ( Section 4.2.4 ).
4.2.4
Step 4. Ultrasound guidance
4.2.4.1
Goal
To identify the optimal segment of the femoral artery for obtaining access. Specifically, access should be obtained above the common femoral artery bifurcation, in a nondiseased arterial segment.
- •
Routine ultrasound use for obtaining vascular access (arterial and venous) is strongly recommended, as it improves the safety and efficiency of obtaining access, as well as the operator’s expertise. It is particularly important for patients with weak pulses, peripheral arterial disease, or obesity, when attempts to obtain access using palpation fail, and when both arterial and venous femoral access is required .
4.2.4.2
How?
- 1.
Gel is applied on the ultrasound probe tip (outside the sterile cover—gel should have also been used over the ultrasound probe before inserting it into the sterile cover).
- 2.
The probe is positioned above the lower tip of femoral head line, drawn on step 2.
- 3.
The common femoral artery is identified and scanned up and down ( Fig. 4.8 ) to identify the location of the common femoral artery bifurcation ( Fig. 4.9 ) and the presence of femoral artery calcification or disease. Gain and depth are adjusted to optimize imaging.
- •
The femoral artery is located lateral to the femoral vein ( Fig. 4.10 ) and, unlike the vein it cannot be collapsed upon compression.
Figure 4.10
Anatomic location of the femoral artery and vein.
Reproduced with permission from Netter, Atlas of Anatomy. Copyright Elsevier.
Figure 4.8
Ultrasound guidance for obtaining femoral access.
Figure 4.9
Illustration of the common femoral artery bifurcation. Imaging above the bifurcation ( right panel ) and below the bifurcation ( left panel ).
Adapted with permission from Sandoval Y, Burke MN, Lobo AS, et al. Contemporary arterial access in the cardiac catheterization laboratory. JACC Cardiovasc Interv 2017;10:2233–41 (Figure 1). Copyright Elsevier.
- •
- 4.
The puncture site is selected based on the following criteria:
- •
Located above the common femoral artery bifurcation.
- •
Away from calcification ( Fig. 4.11 ) , intraluminal disease/narrowing, bypass grafts, and previously placed closure devices, such as recently deployed Angioseals, etc.
Figure 4.11
Severe calcification of the common femoral artery ( arrow ).
Reproduced with permission from Sandoval Y, Burke MN, Lobo AS, et al. Contemporary arterial access in the cardiac catheterization laboratory. JACC Cardiovasc Interv 2017;10:2233–41. Copyright Elsevier.
- •
4.2.4.3
Challenges
- 1.
The femoral artery cannot be identified. Potential causes include obesity, prior surgery, suboptimal drape placement, limited operator experience, or common femoral artery disease.
Solutions:
- •
Use color Doppler to identify flow.
- •
Reexamine the X-ray landmarks ( Section 4.2.2 ).
- •
Reposition the sterile drape (sometimes the drape is placed too high or too low).
- •
Change to an alternative access site (such as contralateral femoral or radial).
- •
Change imaging depth or gain of the ultrasound probe.
- •
- 2.
Calcification throughout the length of the common femoral artery. In such cases alternative access sites are preferable.
4.2.5
Step 5. Local anesthetic administration
4.2.5.1
Goal
To eliminate or attenuate the discomfort from obtaining arterial access.
4.2.5.2
How?
- 1.
A syringe (usually 10 cc) is loaded with local anesthetic.
- 2.
The syringe needle (usually 26–31 gauge) is inserted in the skin.
- 3.
Aspiration is performed to confirm that the tip of the needle is not within a vessel.
- 4.
10–20 cc of local anesthetic are administered in the subcutaneous tissue close to the target femoral artery. To administer >1 syringe of local anesthetic while minimizing the patient’s discomfort, the needle can be left in place within the skin, while exchanging the empty syringe for a full one ( Fig. 4.12 ).
Figure 4.12
Local anesthetic administration for obtaining femoral access.
- 5.
Ultrasound can help visualize the location of the anesthetic administration, which should be targeted around the common femoral artery target puncture site.
4.2.5.3
Challenges
- 1.
Unable to visualize injection of the local anesthetic in the subcutaneous tissue under ultrasound. In such cases adjustment of the needle angulation is needed to ensure the anesthetic is administered in the area surrounding the planned femoral artery puncture location.
4.2.5.4
What can go wrong?
- 1.
Operator needle injury. It is best to remove the hand that is not holding the local anesthetic syringe from the groin area while administering the local anesthetic (which would be the left hand for right-handed operators). An additional advantage of the ultrasound is that the probe is on the skin over the artery instead of the operator’s fingers.
- 2.
Inadvertent puncture of the common femoral artery or vein with the local anesthetic needle. The needle is repositioned before further administration of local anesthetic. If a significant amount of blood enters the local anesthetic syringe, its contents are discarded, and a new syringe loaded with local anesthetic is used.
4.2.6
Step 6. Femoral artery puncture
4.2.6.1
Goal
Puncture the common femoral artery at the desired location and position the access needle tip inside the artery.
4.2.6.2
How?
- 1.
The target femoral artery entry site and the access needle are visualized with ultrasound.
- 2.
The needle entry site and angulation are adjusted to enable puncture at the desired location ( Fig. 4.13 ) . The ultrasound probe should be held perpendicular to the skin surface.
Figure 4.13
Illustration of the angulation required to puncture the femoral artery. As the angle of puncture becomes more shallow, the entry point should move further away from the ultrasound probe.
Reproduced with permission from Sandoval Y, Burke MN, Lobo AS, et al. Contemporary arterial access in the cardiac catheterization laboratory. JACC Cardiovasc Interv 2017;10:2233–41 (Figure 1). Copyright Elsevier.
- 3.
The needle is inserted with the bevel facing up.
- 4.
The access needle is advanced under ultrasound visualization until it enters into the common femoral artery at the target entry location. The angulation of the needle is adjusted depending on the depth of the artery ( Figs. 4.13 and 4.14 ).
Figure 4.14
Adjustment of the needle entry point and the angle of advancement depending on the depth of the femoral artery. For patients in whom the femoral artery is located deeper, either the skin entry point is moved caudally (option 1, preferred) or the needle advancement angle is steeper (option 2).
- 5.
Entry into the artery is confirmed by blood flow through the back end of the access needle.
- 6.
Blood flow is confirmed from the hub of the needle ( Figs. 4.15 and 4.16 ).
Figure 4.15
Pulsatile flow from the access needle upon entering the femoral artery.
Figure 4.16
Pulsatile flow from the access needle upon entering the femoral artery.
- 7.
If a micropuncture needle is used (21 gauge) arterial blood flow is less evident compared with an 18 gauge needle, although pulsatile flow should ideally be present.
- 8.
If an 18 gauge needle is used, the next step is step 9 (insertion of a 0.035 in. guidewire).
4.2.6.3
Challenges
- 1.
Unable to visualize the needle.
Solutions: (1) change the needle entry point; (2) change the location and angulation of the ultrasound beam; (3) use needles with markings that have enhanced visualization under ultrasound.
- 2.
No blood return.
This could be due to suboptimal needle tip location (outside or along the wall of the target artery) or due to plugging of the needle.
Solutions: (1) reposition the needle; (2) remove and flush the needle.
- 3.
Inadvertent puncture of the femoral vein. In this case usually darker nonpulsatile blood flow is seen.
Solution: The needle is partially withdrawn and redirected laterally.
4.2.6.4
What can go wrong?
- 1.
High puncture increases the risk of retroperitoneal hematoma. It is best to remove the micropuncture needle and obtain access again.
- 2.
Low puncture increases the risk of pseudoaneurysm. It may be preferable to remove the needle and obtain access again.
4.2.7
Step 7. Insertion of a 0.018 in. guidewire
4.2.7.1
Goal
Advance an 0.018 in. guidewire into the target femoral artery.
4.2.7.2
How?
- 1.
The 0.018 in. guidewire (the wire included in the Cook micropuncture kit is 40 cm long) is advanced through the 21 gauge access needle ( Figs. 4.17 and 4.18 ).
Figure 4.17
Guidewire insertion through the puncture needle.
Figure 4.18
Guidewire insertion through the puncture needle.
- 2.
Fluoroscopy is used to track the wire course, as it might inadvertently enter small branches (e.g., lateral circumflex iliac, inferior epigastric, internal iliac artery) and lead to vessel perforation upon sheath insertion. As is true for all vascular access, the wire should not pushed if any resistance is felt.
4.2.7.3
Challenges
- 1.
Resistance to wire advancement
Causes:
- •
Suboptimal needle position.
- •
Inferior direction of wire upon advancement or entry into a small branch.
- •
Disease or tortuosity in the femoral or iliac artery.
- •
Low puncture (below common femoral artery bifurcation).
Solutions:
- •
Fluoroscopy to assess wire location (see step 8).
- •
If there is resistance in advancing the wire past the needle tip, the wire is removed and the needle is repositioned until there is good backflow of blood—the guidewire is then reintroduced.
- •
If the wire is directed caudally, it is withdrawn and redirected under fluoroscopy.
- •
If the wire is advancing in the anticipated course of the femoral/iliac artery in the presence of tortuosity, advancement continues.
- •
4.2.8
Step 8. Fluoroscopy of the 0.018 in. guidewire
4.2.8.1
Goal
To ensure that the wire is in the anticipated location within the femoral/iliac artery.
4.2.8.2
How?
Fluoroscopy is performed over the groin/iliac artery region. The following are assessed ( Fig. 4.19 ):
- 1.
Guidewire entry site in to the femoral artery—is it within the lower half of the femoral head?
- 2.
Guidewire position—is it following the anticipated course of the iliac/femoral artery?
If the guidewire position is satisfactory, the needle is removed, holding manual pressure over the guidewire to prevent bleeding.
