General description of procedure, equipment, technique
Femoral access: introduction
Femoral access is still the most common mode of vascular access for coronary angiography and intervention in the United States, though transradial access is on the rise. The femoral artery, in a nondiseased state, is a larger caliber artery (permitting larger size catheters) and is less prone to spasm when compared with the radial artery.
For many procedures such as transcatheter valves, given the larger size of the femoral artery, this is the routinely used access site, although subclavian artery and direct aortic access are being increasingly used for transcatheter valves. In addition, most of the peripheral angiography and intervention is performed via the femoral route, although the transradial route can be used by experienced operators using special catheters (longer length catheters).
Indications and patient selection
Femoral access is commonly used for the following purposes:
- As an access site for coronary angiography and intervention (preferred over radial for procedures requiring larger sheath size)
- As an access site for percutaneous structural heart procedures (balloon valvuloplasty, percutaneous valves, etc.)
- As an access site for peripheral vascular angiography and intervention (transradial access can be used with the use of longer length catheters but below knee procedures will be problematic)
- For intraaortic balloon pump/TandemHeart/ECMO/Impella device placement for hemodynamic support
- As a port for arterial access for invasive hemodynamic monitoring (radial access preferred)
Femoral access should be strongly considered in situations where larger sheath size (8 Fr or higher) is required or in patients with prior difficult radial access.
Vascular access site complications are the most frequent cause of complications during coronary angiography and intervention. Most vascular complications are preventable by following good access technique, starting with good patient selection through a thorough history and physical examination. The following should be considered:
- Thorough history—An often underappreciated but extremely important aspect of the procedure. Patient selection is geared toward identifying the need for the procedure, identifying the presence of features that may potentially make femoral access a less attractive option, identifying factors that require pretreatment (contrast allergy, chronic kidney disease, etc.) and recognizing complications of a prior procedure. In addition to a routine review of systems, the history should specifically focus on the presence of symptoms suggestive of:Peripheral artery disease (intermittent claudication/rest pain/foot ulcers)Prior interventions for peripheral arterial disease, including arterial bypass grafts or stenting (anatomy of the graft and site of stent)
Recent femoral access and closure device used (if any)—Re-access at the site of Angio-Seal deployment, which should be done >90 days postprocedure (to allow for resorption of the anchor and the suture) as described below. However, femoral artery re-access within 90 days can be performed 1 cm proximal/distal to the prior arteriotomy site if absolutely necessary.
Any groin complications from prior procedures (pseudoaneurysms, arteriovenous fistulae, retroperitoneal bleeding, ischemic vascular complications, femoral artery dissections, etc),
Presence of active groin infection (skin/subcutaneous tissue)
Prior surgery or radiation therapy to the groin, and
Presence of iliac or aortoiliac aneurysms (size and location)
- The history should also focus on whether the patient can lie supine for the duration of the procedure (chronic low back pain, congestive heart failure, chronic obstructive pulmonary disease, etc.) as it can change the choice for access (femoral versus radial) and choice of postprocedure hemostasis (manual compression vs. vascular closure device use) driven by postprocedure bed rest requirements
- In addition, the history should focus on patients prior experience and potential difficulties during prior femoral access procedures
- Medication and contrast allergy history should be taken and a list of current medications including any oral anticoagulant use should be recorded
- Physical examination—In addition to routine examination of the main systems, physical examination should focus on inspection of the groin for any signs of infection or swelling; palpation for the presence of any swelling, palpation of the femoral pulse; and palpation of the distal arterial pulses, including bilateral dorsalis pedis, posterior tibial, and popliteal arteries. In patients with nonpalpable pulses, Doppler auscultation should be used. In addition, auscultation should be performed for any bruits.
- Pertinent findings should be documented in the patient’s chart
- Presence of any of the above conditions should prompt strong consideration for an alternative approach, such as radial (preferred) or brachial artery, although these are not absolute contraindications for a femoral artery approach.
- In addition, if patient had a prior procedure via femoral access, review of any prior femoral angiogram can provide much valuable information about the anatomy and its variants and may considerably lessen difficulty with access and postprocedure complications.
- Basic laboratory values should be reviewed before the procedure. These include hemoglobin; platelet count; coagulation panel (prothrombin time/partial thromboplastin time/international normalized ratio [PT/PTT/INR]) for patients on anticoagulation, those with liver disease, or bleeding diathesis; electrolyte panel; and creatinine. Women of child-bearing age should have a urine/serum beta-hCG checked within 2 weeks prior to the procedure.
There is no absolute contraindication for femoral access. However, caution must be exercised and alternative routes considered in the following circumstances:
- Absent or weak femoral artery pulse (consider contralateral femoral artery, radial access, or use of SMART needle or ultrasound guided femoral access as described below)
- Recent use of vascular closure device (see re-access restrictions below)
- Iliofemoral bypass grafts (consider contralateral femoral artery, radial access, or use of micropuncture needle for femoral access as described below)
- Prior vascular complications, such as pseudoaneurysm, arteriovenous fistula, dissection, ischemic limb (consider contralateral femoral artery or radial access)
- Prior groin surgery with excessive scarring/radiation therapy (consider contralateral femoral artery or radial access)
- Known aneurysm of the iliofemoral or aortoiliac system (consider radial access)
- Morbid obesity (consider radial access)
- Inability to lie supine for the duration of the procedure (patients with chronic back pain, heart failure, chronic obstructive pulmonary disease, etc.)
Of note, none of the above are absolute contraindications for femoral access and the procedure can be performed using a small size catheter (4 or 5 Fr). However, when possible the unaffected femoral artery (left vs. right) should be chosen to minimize risk.
Femoral artery anatomy and ideal puncture site
Femoral artery anatomy
Knowledge of the normal course of the common femoral artery (CFA) is vital as the majority of arterial access complications are related to the site of femoral arterial puncture.
- The CFA is a continuation of the external iliac artery and crosses the pelvic brim at the level of the inguinal ligament.
- The CFA then passes through the femoral sheath and branches into the superficial femoral artery and the profunda femoris artery.
- The femoral sheath has three compartments. The lateral compartment contains the femoral artery, the intermediate compartment contains the femoral vein, and the medial and smallest compartment is called the femoral canal, which contains efferent lymphatic vessels and a lymph node embedded in a small amount of areolar tissue.
- Lateral to the femoral artery and outside the femoral sheath is the femoral nerve.
- The relationship between CFA, femoral vein, and the femoral nerve can be easily remembered by the mnemonic VAN (Vein, Artery, Nerve) going from medial to lateral.
Ideal femoral arterial puncture site
- The ideal site of femoral arterial puncture (not skin puncture) is at the CFA at a point approximately 1 cm lateral to the most medial aspect of the femoral head, midway between its superior and inferior borders (Rupp’s rule).
- Low cannulation below the bifurcation of the CFA is associated with greater propensity for complications—ischemic arterial complications (due to smaller size of the artery) and arteriovenous fistulae (tributaries of the femoral vein course above the superficial femoral artery at this location).
- High cannulation above the inguinal ligament (in the external iliac artery) is associated with an increased risk of retroperitoneal hemorrhage due to lack of an underlying bony structure preventing effective compression and tamponade
- The optimal location for femoral arterial puncture is best assessed from prior femoral angiograms when available. In patients without prior femoral angiograms, various external landmarks have been used to access the femoral artery such as the skin/inguinal crease (unreliable in obese patients), based on bony landmarks (a point 2 to 3 cm below the mid inguinal point, which is the midpoint between the anterior superior iliac spine and pubic tubercle), based on the site of the maximal femoral pulse, and based on fluoroscopic landmarks.
- Landmarks, other than fluoroscopic landmarks, are highly variable based on the patient’s body habitus and are less reliable at identifying the ideal site.
- Fluoroscopic landmark: This is the preferred approach for femoral access. The technique employs visualization of the femoral head under fluoroscopy in a posterior-anterior (PA) projection. A metal hemostat is used as a marker to identify the best location for femoral artery cannulation as described above. This is achieved by a skin puncture done at the lower border of the femoral head with the needle entering the skin at a 30- to 45-degree angle (steeper angle in more obese patients). Advantage: greater reliability at identifying the “ideal” femoral arterial puncture site. Disadvantage: will not identify normal anatomic variants such as high femoral artery bifurcation or a femoral vein overlying the artery.
Details of how the procedure is performed
- Prior to the procedure, patient should be well informed about the steps of the procedure to ensure adequate understanding and cooperation. A well-informed patient makes for a more cooperative patient.
- Ensure that a written informed consent is obtained prior to the procedure.
- Review basic laboratory values (preferably obtained in the prior 2 weeks).
- Ensure that women of child-bearing age have a negative urine/serum beta-hCG test within 2 week prior to the procedure.
- If the procedure requires conscious sedation, patient should refrain from oral intake for at least 4 hours prior to the procedure. However, in case of emergency, the risk of aspiration should be weighed against the benefits of the procedure.
- Diabetes: In patients with diabetes, oral hypoglycemics should be withheld on the morning of the procedure, the procedure should be scheduled early in the morning, and the serum glucose level monitored as required. Metformin should be withheld on the day of the procedure and for at least 48 hours postprocedure to prevent lactic acidosis. However, in patients with preserved renal function, this may not be absolutely necessary.
- Chronic kidney disease: In patients with preexisting chronic kidney disease, preprocedure hydration with isotonic saline for 3 to 12 hours before the procedure and continuing for 6 to 12 hours postprocedure is recommended to prevent contrast-induced acute kidney injury. Potentially nephrotoxic medications (such as NSAIDS) should be withheld the morning of the procedure.
- Anaphylactoid reaction to contrast media: Patients with a prior history of anaphylactoid reaction to contrast media should receive steroid and antihistamine prophylaxis prior to contrast administration. The current recommendations are 50 mg of oral prednisone at 13 hours, 7 hours, and 1 hour before the procedure with an H2-receptor blocker. In case of emergency, 200 mg IV hydrocortisone should be administered along with an antihistamine and an H2-receptor blocker.
- Patients on anticoagulation: Patients on warfarin should stop warfarin at least 3 days prior to the procedure and an INR should be checked prior to the procedure.
- Prior to the procedure and before sedation, a “time out” should be performed to ensure that the correct procedure is performed on the appropriate patient. This includes verification of patient name and procedure, and verification of correct site and side used.
- Prepare the femoral artery site using antiseptic solution and dry it using a dry gauge
- Cover the site with a sterile drape, with an opening at the site of the femoral access site
- Ensure adequate conscious sedation (minimal to moderate sedation) for patient cooperation (for example, 1 mg of midazolam and 25 mcg of fentanyl IV; dose titrate carefully in the elderly). The regimen will vary by the catheterization laboratory with some labs using preprocedural oral diazepam (5 mg) and Benadryl (25 mg) followed by IV administration in the lab.
- The conscious sedation should be such that the patient should feel comfortable and sleepy but yet arousable and conversant enough to indicate pain or other discomfort.
- Prepare the patient prior to a potentially painful step of the procedure (e.g., administering local anesthesia) by informing him or her of the next step to ensure adequate patient cooperation.
- Identify the ideal femoral artery puncture site as described above. Mark the site using a curved artery forceps that corresponds to the lower border of the femoral head on fluoroscopy.
- Feel the femoral arterial pulsation at the site of skin entry with the tips of the middle and index fingers, and parallel to the course of the femoral artery.
- Inform patient that you will be administering local anesthesia.
- Start with a dermal bleb using a 25-gauge needle to anesthetize the skin. Using a long 22-gauge needle, anesthetize deeper tissue planes and on either side of the femoral artery. Administer 10 to 20 cc of local anesthesia, good enough for patient comfort but not so excessive as to obscure pulsations.
- Make a 2 to 4 mm nick parallel to the skin crease at the identified site of the femoral artery puncture. The nick can be enlarged and deepened using the tip of a small curved forceps. The nick and tunnel approach may not be necessary for smaller size sheaths.The disadvantage of the nick and tunnel approach is the need for a repeat nick in case the nick was not performed at the site of the artery. In addition, it may be preferable to perform the nick once the femoral artery has been entered with an 18-gauge needle. Care must be taken not to make the nick over a soft guidewire (such as a hydrophilic wire) to avoid the risk of cutting the wire.
- Puncture the artery using an 18-gauge arterial cannulation needle using a modified Seldinger’s technique with an anterior wall puncture. Avoid back wall puncture whenever possible. Enter the skin at a 30- to 45-degree angle so as to cannulate the artery 2 cm superior to the skin incision.
- Ensure pulsatile blood flow before wire advancement. Advance a 0.035 inch J-tip guide wire and confirm the position under fluoroscopy. If any resistance is encountered during wire advancement, advance under fluoroscopy.
- With sufficient length of wire in place, exchange the cannulation needle to a femoral arterial sheath.
- Remove the dilator leaving behind the J-tipped guidewire and flush the side port of the sheath.
- Perform femoral angiography in the ipsilateral oblique view and preferably prior to the start of the procedure to identify the site of femoral artery cannulation and to assess for any complications (perforation, dissection, etc.). It may be a good practice to leave the J-tipped guidewire in the artery prior to femoral angiography. This will ensure that the tip of the femoral artery sheath is not buried into a plaque as injecting dye into it can lead to femoral artery dissection; also, this practice prevents inadvertent pulling out of the sheath during angiography.
Special techniques/situations for Femoral Arterial Access
Femoral arterial access can also be obtained by the below techniques:
- Real-time ultrasound guided: A vascular ultrasound probe (5 to 10 Hz) can be used to locate the CFA and arterial access obtained under direct ultrasound guidance. Add ultrasound gel on the vascular probe and cover the probe with a sterile sleeve. Add additional ultrasound gel over the sleeve.First locate the bifurcation of the femoral artery. Once the bifurcation is identified, trace the artery proximally to identify the common femoral artery. Under direct ultrasound guidance advance the 18-gauge needle. As the needle passes through the tissue planes, the indentation on the artery by the advancing needle can be identified on the ultrasound.Adjust the direction of the needle based on the position on the ultrasound and puncture the artery. Some ultrasound probes have a needle guide that fixes the angle of entry of the needle to within the area of the ultrasound beam and thus aids in easy puncture.
Advantage: Avoids cannulation at the bifurcation in arteries with a high bifurcation and reduces the chances of arteriovenous fistula by avoiding cannulation of the femoral vein at sites where the femoral vein is directly on top of the artery.
Disadvantage: Additional time taken to set up the ultrasound and the need for a ultrasound probe and console.
- Doppler integrated (SMART) needle: The SmartNeedle (Escalon Vascular Access, New Berlin, WI) is a flow needle attached to a Doppler probe, which can be used in patients with a difficult to palpate pulse. The probe is within the lumen of the needle. The needle is connected to a handheld Doppler monitor wrapped in a sterile sleeve where the Doppler sound is amplified so that the performing physician can hear the sound as the needle approaches the artery or the vein.Advance the needle similar to that of the standard gauge needle while listening to the Doppler signal. When the needle approaches the artery, the Doppler signal becomes louder, assisting in femoral arterial cannulation. Once the needle enters the artery, ensure pulsatile blood flow and the rest of the procedure is as described above.
- Using micropuncture needle: In patients who are fully anticoagulated, it may be desirable to obtain femoral access using a smaller gauge needle to reduce the risk of access site complications. The micropuncture needle is a 21-gauge needle compared with a standard 18-gauge needle.The micropuncture kit consists of a 21-gauge stainless steel needle, a 0.018-inch guidewire with soft flexible tapered tip, and a 4 Fr x 10 cm micropuncture sheath with dilator. Advance the micropuncture needle similar to the standard gauge needle. Once the artery is cannulated, ensure adequate blood flow but bearing in mind that the blood flow may not be as pulsatile as that with a standard gauge needle. Insert and advance the 0.018-inch guidewire, preferably under fluoroscopic guidance.Remove the micropuncture needle over the guidewire and exchange for the 4 Fr micropuncture sheath and dilator. Remove the dilator and the guidewire. Brisk pulsatile arterial flow should be noted at this stage. Use a 0.035 inch J-tip guidewire through the micropuncture sheath and exchange the sheath for a regular 5 to 8 Fr femoral artery sheath. Never attempt to remove the 0.018-inch guidewire with the micropuncture needle in place as it can shear away the guidewire.
- Iliofemoral bypass grafts: In patients with post iliofemoral bypass grafts, an alternate approach such as transradial approach or femoral approach via the nongrafted site should be considered. However, a prior iliofemoral bypass graft in itself is not a contraindication for ipsilateral femoral access and access can be obtained safely using a micropuncture needle (described above).
- Morbidly obese patients: In morbidly obese patients, an alternate approach such as transradial approach should be considered. However, if the femoral approach is chosen, the needle should enter more vertically to avoid a high stick. Use of micropuncture needle may be desirable.
Complications and their management
Femoral access site complications are perhaps the most common complications in patients undergoing coronary angiography and interventions. Recognition and early treatment of these complications can prevent more serious complications and death.
- Arteriovenous (AV) Fistula: The incidence of AV fistula after femoral arterial cannulation is <1.0%. Femoral arteriovenous fistulae are abnormal communications between femoral artery and the femoral vein at the site of sheath insertion. The risk factors for AV fistulae are: Low femoral puncture (puncture of the profunda femoris vein that lies close to the superficial femoral artery), multiple punctures, through and through puncture of overlying vein, large sheath size, ineffective manual compression, female gender, anticoagulant and antifibrinolytic therapy, therapeutic procedures (as opposed to diagnostic procedures), older age, and arterial hypertension.Clinical evaluation: Usually asymptomatic. Patients can complain of abnormal sensation on the groin (vibration like) or fatigue (due to shunting). In rare cases may cause high-output heart failure, venous insufficiency with varicose veins, lower extremity edema, and steal syndrome with intermittent claudication/distal limb ischemia. Physical examination: Bruit/machinery murmur, swelling/massDiagnosis: Duplex ultrasound is the test of choice. Arteriography (CT or angiography) is rarely required.
Treatment: Small AV fistula needs only observation and serial ultrasound and the fistula usually closes by itself (spontaneous thrombosis). For larger AV fistula and if patient is symptomatic, ultrasound guided compression for up to 1 hour is recommended. Other treatment options include: surgery (ligation), endovascular repair using a covered stent ,or coil embolization.
- Pseudoaneurysm: Incidence of pseudoaneurysm is between 1% and 3%. Pseudoaneurysm occurs when there is communication between the artery and overlying hematoma such that the blood flows intermittently during systole and diastole into the hematoma sac. The risk factors for pseudoaneurysm are: low femoral puncture (puncture of the superficial femoral artery), large sheath size, ineffective manual compression, anticoagulant and antifibrinolytic therapy, older age, and arterial hypertension.Clinical evaluation: Patients present with pain and swelling at the access site or may be asymptomatic. Physical exam reveals a pulsatile swelling with a bruit.Diagnosis: Duplex ultrasound. Arteriography (CT or angiography) is rarely required.
Treatment: Small (≤2 cm)—observation and serial ultrasonography. Large—ultrasound guided compression (30 to 300 min)/thrombin or collagen injection, or surgical repair.
- Dissection: Retrograde dissection of the femoral artery occurs as a result of the needle or the guidewire entering the dissection plane at the time of femoral artery cannulation. In addition, dissection can occur during femoral angiography if the sheath is up against the wall of the femoral artery (angiography with the guidewire in place will reduce the chance of this occurrence as described above).Most dissections are discovered on femoral angiography and are usually asymptomatic. The dissection flap is held open by the antegrade flow of blood and rarely results in complete occlusion of the femoral artery.Diagnosis: Most dissections are discovered on femoral angiography. Dissections resulting in femoral artery occlusion will result in ipsilateral lower leg pain with signs of arterial insufficiency (5 Ps described below).
Treatment: Most dissections without occlusion are usually asymptomatic and no definitive treatment is needed. However, if the dissection is discovered on femoral angiography, it may be prudent to withdraw the sheath back and repeat femoral angiography using hand injection of contrast to ensure that the artery will not completely occlude upon sheath removal. In patients with femoral artery occlusion, contralateral access with attempted percutaneous or surgical approaches to femoral artery recanalization will be required. Acute ischemic limb is a surgical emergency and is described below.
- Acute Limb Ischemia: Rare with an Incidence of less than 1.0%. Acute limb ischemia may be due to a thrombus at the site or due to femoral artery dissection (antegrade). In rare cases, it may be due to complication of vascular closure device use (embolization of foot plate of Angio-Seal device, suturing the circumference of the artery with a Perclose device). Risk factors include a small caliber artery (women, those with PAD, diabetics), using larger size sheaths, female gender, longer catheter dwell time, or superficial femoral or profunda cannulation (especially if the artery has a smaller lumen)Signs and symptoms: 5 Ps—Pain, Pallor, Paresthesia, Pulselessness, Power (loss)Treatment: It is an emergency and prompt contralateral access and angiography and possible thrombectomy/angioplasty and stenting; intraarterial fibrinolytics or surgery can also be used
- Retroperitoneal hemorrhage: Retroperitoneal hemorrhage is a rare but serious complication of femoral arterial access with an incidence of less than 3%. Risk factors include: high puncture, use of glycoprotein IIb-IIIa inhibitors, and posterior wall puncture.Clinical evaluation: Flank/back pain. Hypotension sometimes mimicking vasovagal reaction with bradycardia. However, this minimally responds to atropine. Physical exam: Hypotension, tachycardia, Turner’s sign, Cullen’s signDiagnosis: Obtain computed tomography (CT) image of pelvis (without contrast). Alternatively, iliofemoral angiography can identify the site of perforation.
Treatment: Fluid resuscitation with crystalloids and blood transfusion. Contralateral access with balloon tamponade and/or use of covered stent or emergent surgery.
What’s the evidence?
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Rupp, SB, Vogelzang, RL, Nemcek, AA, Yungbluth, MM. “Relationship of the inguinal ligament to pelvic radiographic landmarks: anatomic correlation and its role in femoral arteriography”. J Vasc Interv Radiol. vol. 4. 1993. pp. 409-13.
Huggins, CE, Gillespie, MJ, Tan, WA. “A prospective randomized clinical trial of the use of fluoroscopy in obtaining femoral arterial access”. J Invasive Cardiol. vol. 21. 2009. pp. 105-9.
Abu-Fadel, MS, Sparling, JM, Zacharias, SJ. “Fluoroscopy vs. traditional guided femoral arterial access and the use of closure devices: A randomized controlled trial”. Catheter Cardiovasc Interv. 2009.
Dudeck, O, Teichgraeber, U, Podrabsky, P, Lopez Haenninen, E, Soerensen, R, Ricke, J. “A randomized trial assessing the value of ultrasound-guided puncture of the femoral artery for interventional investigations”. Int J Cardiovasc Imaging. vol. 20. 2004. pp. 363-8.
Vucevic, M, Tehan, B, Gamlin, F, Berridge, JC, Boylan, M. “The SMART needle. A new Doppler ultrasound-guided vascular access needle”. Anaesthesia. vol. 49. 1994. pp. 889-91.
Altin, RS, Flicker, S, Naidech, HJ. “Pseudoaneurysm and arteriovenous fistula after femoral artery catheterization: association with low femoral punctures”. AJR Am J Roentgenol. vol. 152. 1989. pp. 629-31.
Rapoport, S, Sniderman, K, Morse, S, Proto, M, Ross, G. “Pseudoaneurysm: a complication of faulty technique in femoral arterial puncture”. Radiology. vol. 154. 1985. pp. 529-30.
Ellis, SG, Bhatt, D, Kapadia, S, Lee, D, Yen, M, Whitlow, PL. “Correlates and outcomes of retroperitoneal hemorrhage complicating percutaneous coronary intervention”. Catheter Cardiovasc Interv. vol. 67. 2006. pp. 541-5.
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- General description of procedure, equipment, technique
- Indications and patient selection
- Details of how the procedure is performed
- Complications and their management
- What’s the evidence?