Cardiology

Ultrasound Guided Femoral Access in Peripheral Interventions

General description of procedure, equipment, technique

Ultrasound-guided retrograde common femoral artery access (UG-CFA access)

While radial artery access is rapidly replacing the traditional common femoral artery access in coronary angiography, CFA-access remains the primary route for performing peripheral angiography and interventions. We routinely combine ultrasound guidance with fluoroscopy guidance.

We believe such an approach improves the cannulation success rate and allows for establishing an access safely, particularly when anatomic variations are present (CFA bifurcation above the femoral head). Ultrasound guidance allows for selecting a preferred segment for cannulation, avoiding problematic (plaque, heavily calcification) areas, and achieving a puncture in the center of the artery.

US guidance is likely associated with a lower vascular access complication rate, and likely improves chances for using closure devices (if desired). Furthermore, the use of US guidance to obtain CFA access does not significantly prolong procedure time or increase costs.

Indications and patient selection

We advocate routine practice of UG-CFA access in all patients. We propose that patients who are obese, have hypotension, prior history of peripheral artery disease, peripheral stents or grafts; prior unsuccessful cannulation attempts, and those with diffuse pulses must undergo UG-CFA access.

Contraindications

The only contraindications for routine use of UG-CFA access is the lack of good quality US machine and unavailability of trained operators.

Details of how the procedure is performed

1. After the patient is placed on the angiography table, we start by identifying anatomic landmarks as usual (palpation, point or maximal impulse, and fluoroscopy).

2. Mark the area indicated above to be the potential access site.

3. Interrogate the CFA with the sterile (sleeved) vascular US probe (linear, 7.5 MHz), first in the transverse (short-axis, SAX), then in the longitudinal (long-axis, LAX) view, and assess the following:

  • Presence of plaques or other abnormalities

  • Level of bifurcation (average, high, or low)

  • Relationship between the artery and vein (parallel, overlapping)

  • Document arterial blood flow pattern by continuous pulse Doppler

4. Definitive identification of the CFA bifurcation is mandatory:

  • First, in the SAX position

  • Then in the LAX position

  • Document arterial systolic-diastolic blood flow pattern in the CFA, SFA and profunda arteries while in the LAX view (small sample volume, <0.5 cm is recommended)

5. Use the micropuncture kit to obtain initial access after applying adequate local anesthesia (1% to 2% lidocaine) and performing the neck and blunt dissection (which allows for outward bleeding if bleeding occurs and reduces the risk of occult hematoma).

6. The CFA may be accessed in either orientation, although our preference is the LAX view as it allows for:

a. Exposure of the entire CFA, therefore allowing for thoughtful accurate selection of the entry site

b. Visualization of the femoral head, the bifurcation, and the iliac artery as it dives into the pelvis

c. Advancing the microwire retrogradely under direct visualization

7. Occasionally, we use fluoroscopy to monitor the advancement of the microwire.

8. Exchange the microwire for the microdilator and perform CF arteriography in the ipsilateral (RAO for R-CFA and LAO for L-CFA) 30-to 45-degree angulation will open the SFA-profunda bifurcation.

9. If satisfactory, we then exchange for a diagnostic (typically Brite Tip) 4 or 5 Fr sheath and proceed with abdominal aortography with pelvic and lower extremity run off (see special chapter.)

10. By the end of procedure, the operator already has adequate information on the access site and can decide if a closure device would be appropriate.

Interpretation of results

The US provides detailed anatomic information beyond the location of the bifurcation (see above).

Performance characteristics of the procedure (applies only to diagnostic procedures)

The test is accurate and permits for direct visualization of the needle traversing to the arterial wall and advancement of the guide wire. Clinical trial data showed overall similar CFA cannulation success rates compared with those achieved by flouroscopic guidance. Better success rates were seen in individuals who have high CFA bifurcation.

In those, US guidance improved the first-pass success rate (83% vs. 46%, P <.0001), reduced number of attempts (1.3 vs. 3.0, P <.0001), reduced risk for venipuncture (2.4% vs. 15.8%, P <.0001), and reduced median time to access (136 vs. 148 sec, P =.003).

Alternative and/or additional procedures to consider

Axillary artery (preferred over brachial or radial artery if the extra distance from the brachial or radial site does not allow delivery of equipment to the distal lower extremities), popliteal artery (patient positioned in the prone position), antegrade CFA (should be avoided in obese patients), and tibial artery access can be considered in selective cases where retrograde CFA access proved unattainable, unfavorable, or unnecessary. Lumbar aortic punctures (last resort) should only be performed by experienced operators in very selective cases.

Complications and their management

Vascular complications, including hematoma, arteriovenous fistula (AFV), and pseudoaneurysm (PSA) are all possible, albeit less likely with ultrasound guidance. A major advantage of US guidance is that it decreases the risk of high and low sticks, therefore lowering the risk of retroperitoneal hemorrhage (with high sticks) and PSA/AVF (with lower sticks).

What’s the evidence?

Seto, AH, Abu-Fadel, MS, Sparling, JM. "Real-time ultrasound guidance facilitates femoral arterial access and reduces vascular complications: FAUST (Femoral Arterial Access With Ultrasound Trial)". J Am Coll Cardiol Intv. vol. 3. 2010. pp. 751-8.

(Pivotal trial that showed efficacy and safety of US-guided femoral access and advanced it to become standard practice.)

Troianos, CA, Hartman, GS, Glas, KE. "Guidelines for performing ultrasound guided vascular cannulation: Recommendations of the American Society of Echocardiography and the Society of Cardiovascular Anesthesiologists". J Am Soc Echocardiogr. vol. 24. 2011. pp. 1291-318.

(Multisocietal guidelines that advocate using US-guided access in multiple scenarios, including femoral access. The guidelines support that US-guidance improves success rate and boosts safety.)
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