Vascular Access and Closure

Using a Micropuncture Needle

The standard Seldinger needle used for the femoral artery cannulation is an 18-gauge needle. A micropuncture needle is a 21-gauge needle, which decreases the size of the hole by 56% and the flow through the hole by nearly sixfold over a standard 18-gauge needle, potentially decreasing complications from errant sticks or inadvertent back wall punctures. However, there are no robust data to support the routine use of micropuncture in all cases to reduce the risk of femoral access site complications. For access using a micropuncture needle, the skin is entered at the site corresponding to the lower border of the femoral head on fluoroscopy using the 21-gauge needle. Some operators use fluoroscopy before entering the vessel to ensure that the tip of the needle is at the desired site and repositioning as needed. After ensuring blood flow from the hub (may not be as pulsatile), a floppy-tipped 0.018-inch guidewire is then advanced into the CFA and the external iliac artery. Advancing the guidewire under fluoroscopy may be preferred as resistance to advancement is better seen than felt with the finer guidewire of the micropuncture set. The needle is now exchanged for a 4 Fr short catheter with a 3 Fr inner dilator. Both the guidewire and the dilator are removed, at which point there should be pulsatile blood flow, followed by introduction of the 0.035/0.038-inch guidewire and exchange of the 4 Fr catheter to the appropriate size femoral sheath. Alternatively, the inner dilator can be used to perform a femoral angiogram. If the cannulation site is too high or low, the dilator is removed and pressure is applied to ensure hemostasis and reaccess are performed at the optimal location.

Using a SmartNeedle Percutaneous Doppler Vascular Access Device

In patients with a difficult to palpate femoral pulse, the SmartNeedle (Vascular Solutions, Inc., Minneapolis, Minn.) may be helpful. The SmartNeedle consists of a detachable Doppler probe inside the lumen of a standard introducer needle. This is connected to a handheld monitor by a cable and the flow is detected by an audio output. Attach the cable of the needle to the connector on the SmartNeedle monitor, turn the monitor on, and adjust the volume as needed. Test the system by dipping the needle in water and moving it back and forth. An audible Doppler signal should be heard. Flush the needle with saline to remove any air. Now insert the needle through the skin with a saline syringe connected, while listening to the Doppler signal. Express a small amount of saline through the tip to clear any air bubbles. Move the needle in a circular motion while listening to the Doppler flow signal. As the needle approaches the artery, the Doppler signal becomes louder and pulsatile, thus assisting femoral arterial cannulation. Arterial flow may be identified as a pulsatile high frequency sound whereas the venous flow is a low frequency sound. Care must be taken not to palpate the artery/vein while advancing the needle, as this can compress the vein and obliterate the venous signal. Once a Doppler signal is detected, the area should be scanned for the loudest signal and then the needle further advanced in the direction. Once the needle enters the artery, there is a pulsatile flow of blood (may not be as brisk as a regular needle due to the probe in place). The Doppler probe is now removed from the needle, a guidewire is inserted, and the other steps are similar to what is described in Table 3-2 . When compared with a standard needle, the SmartNeedle has been shown to result in a greater proportion of successful femoral arterial cannulations on first attempt and to reduce the risk of hematoma.

Using Ultrasound Guidance

For patients with a difficult to palpate femoral artery pulse, femoral artery cannulation under ultrasound guidance is an option. Arterial cannulation under ultrasound guidance is similar to central venous access using a similar approach. The advantage of this approach is direct visualization of the artery prior to cannulation thereby avoiding cannulation into diseased segments, cannulating branch arteries when there are anatomic variants (high bifurcation), or accidental venous puncture in anatomical variants where the femoral vein (or its tributaries) lies directly above the artery. The disadvantage is the need for a vascular transducer probe and extra time to set up the equipment and for the additional steps involved. The technique involves using a 7-MHz vascular transducer probe draped in a sterile sleeve. The ultrasound is then held at the site of the proposed skin puncture site (determined on fluoroscopy) and moved caudally to visualize the femoral bifurcation and then cranially ( Figure 3-4 ). The femoral artery can be differentiated from the femoral vein, as it is less compressible, by the direction of blood flow on color Doppler ultrasonography, and by a triphasic signal (versus a more monophasic signal for the femoral vein) on pulse Doppler ultrasonography ( Figure 3-5 ). Once a relatively disease-free segment is identified in the CFA, arterial cannulation can be performed under direct ultrasound guidance holding the ultrasound probe in one hand or by a second operator and the needle in the other hand. Local anesthesia is administered around the artery under direct ultrasound guidance. The Seldinger needle is then used and its position adjusted based on the ultrasound image until the artery is cannulated and confirmed by pulsatile blood. An ultrasound probe with an integral needle guide and built-in needle position sensors are now available ( Figure 3-4 ). Together these project on the ultrasound monitor an enhanced virtual image of the needle as it moves through the tissue toward and into the target vessel. Once the path is confirmed on the monitor, the needle is inserted through the needle guide while advancing the needle under direct ultrasound visualization and confirmed by pulsatile blood ( Figure 3-4 ). The guidewire is then inserted and the needle exchanged for an appropriate size femoral artery sheath as described previously.

Ultrasound-guided femoral arterial cannulation has been shown to aid vascular access in patients with an absent palpable pulse or after unsuccessful palpation-guided cannulation. However, the data to support ultrasound-guided femoral arterial cannulation in all patients are rather weak. In a randomized trial of ultrasound-guided puncture versus traditional palpation-guided puncture of the femoral artery, ultrasound guidance significantly decreased the number of attempts needed as well as the time for successful arterial puncture only in patients with a weak arterial pulse and in those with a leg circumference of 60 cm or greater. In contrast, time for vessel cannulation was increased in patients with a strong arterial pulse, and there was no difference in femoral arterial complications. In the Femoral Arterial Access With Ultrasound Trial [FAUST], routine real-time U.S. guidance improved CFA cannulation only in patients with high CFA bifurcations but reduced the number of attempts, time to access, risk of venipunctures, and vascular complications in femoral arterial access.

Femoral Arterial Cannulation in a Challenging Patient Subgroup

Bleeding/Hematoma

The femoral arterial access site is a frequent source of bleeding and hematoma. The incidence is around 0.8% to 23% and is the most common access-site-related complication. Patients experiencing major femoral bleeding have a significantly longer postprocedure hospital stay and excess morbidity and mortality in the first 30 days when compared with patients without major femoral bleeding. Contributing factors include a low or high femoral puncture, ineffective manual compression, a back wall femoral arterial wall puncture, accidental puncture of the vein, and the use of glycoprotein IIb/IIIa inhibitors. A hematoma usually presents as swelling surrounding the puncture site, which is often painful and results in difficulty moving the leg and/or skin discoloration. The presentation depends on the size of the hematoma (small <1 cm, medium 1-5 cm, large >5 cm) and the acuity. A large hematoma can present with signs of hemodynamic instability with tachycardia and/or hypotension. Some patients may present with a vasovagal reaction with bradycardia and hypotension due to severe pain and compression of the underlying artery. Treatment includes manual compression at the site of the hematoma, fluid resuscitation/blood transfusion as needed for hemodynamic instability, prolonged bed rest, and interruption/reversal of anticoagulation/antiplatelet agents if necessary. Close monitoring for recurrence by outlining the hematoma and frequent measurement of the girth of the thigh and serial complete blood cell count are important to detect any further bleeding. Rarely surgical evacuation of the hematoma may be required. Many hematoma resolve within a few weeks; however, care must be taken to prevent infection at the site of the hematoma.

Retroperitoneal Hemorrhage

Retroperitoneal hemorrhage, bleeding that occurs behind the serous membrane lining (peritoneum) the walls of the abdomen/pelvis, is usually due to a high femoral puncture above the inguinal ligament (lower margin of the inferior epigastric artery on fluoroscopy) and/or a posterior wall puncture. The incidence is around 0.1% to 0.4% and can be fatal if not recognized early. Risk factors include female gender, low body surface area, high arterial puncture, glycoprotein IIb/IIIa use, and chronic renal insufficiency. Patients usually present with ipsilateral flank or lower back pain, vague abdominal pain, and symptoms and signs of hypotension. Physical examination may show tachycardia and hypotension with Grey Turner's (bruising/blue discoloration of the flanks) or Cullen's (bruising/blue discoloration around the umbilicus) sign ( Figure 3-6 ). Often there is no hematoma at the site of the femoral puncture site and the only manifestation may be tachycardia and hypotension, and therefore a high clinical suspicion is required for early diagnosis. Diagnosis can be confirmed by a CT pelvis without contrast ( Figure 3-7 ) or on femoral angiography showing frank extravasation of contrast into the pelvis ( Figure 3-8 ). Treatment includes fluid resuscitation/blood transfusion as needed for hemodynamic instability, prolonged bed rest, and interruption of anticoagulation if necessary. Serial monitoring of blood pressure and a complete blood count should be performed. Definitive treatment for ongoing hemorrhage includes surgery evacuation of the hematoma with local repair of the artery or contralateral femoral arterial access with balloon tamponade at the site of perforation. In most cases prolonged balloon tamponade will effectively seal the leakage, but in some cases a covered stent may be required.

Arteriovenous Fistula

The incidence of anteriovenous fistula ( Figure 3-9A ) formation after femoral artery cannulation is low (<0.2%). The risk fctors for AV fistula include a low/high femoral puncture, multiple access attempts, puncture of the overlying femoral vein or its tributaries, and ineffective manual compression. Patients maybe asymptomatic or present with pain and swelling at the groin site. Rarely patients present with symptoms and signs of increased cardiac output or limb ischemia (intermittent claudication, ulcer) or deep venous thrombosis. On physical examination a bruit may be heard on auscultation and a thrill felt on palpation. Diagnosis is by color Doppler ultrasound and rarely angiography ( Figure 3-9A ) or CT ( Figure 3-9B ) is needed. For small AV fistula and in asymptomatic patients, the treatment is observation and serial ultrasound. Most resolve with time. For large AV fistula, ultrasound-guided compression is the treatment of choice. Other options include use of a balloon tamponade, covered stent, endovascular coils, and if all else fails, surgical repair.

Pseudoaneurysm

A pseudoaneurysm (PSA) is defined as an arterial rupture of one or more layers of its walls, contained by overlying fibromuscular tissue, which communicates with an artery by a neck or sinus tract. The incidence of pseudoaneurysm is 0.3% to 9.0%. Risk factors for pseudoaneurysm include a low femoral puncture site and ineffective manual compression after sheath removal. The patient usually pre­sents with swelling/pain or a large hematoma at the site. A large pseudoaneurysm can present with symptoms of nerve compression (limb weakness and paresthesia). A pseudoaneurysm can rupture causing abrupt swelling and severe pain. A physical examination may reveal a pulsatile mass with a bruit and/or thrill. Diagnosis is made on color Doppler ultrasonography ( Figure 3-10A ). It can also be diagnosed by angiography or CT ( Figure 3-11 ). Treatment depends on the size of the pseudoaneurysm. A small pseudoaneurysm (≤2 cm) usually resolves spontaneously and requires manual/mechanical compression, prolonged bed rest, and cessation of anticoagulation, followed by observation and serial ultrasonography. A large pseudoaneurysm can be treated by ultrasound-guided manual/mechanical compression or ultrasound-guided thrombin injection ( Figure 3-10B ) into the pseudoaneurysm sac. Rarely surgical repair may be required.

Artery Occlusion

Limb ischemia after femoral arterial cannulation is rare with an incidence of <0.8%. It is usually due to occlusion of the artery by thromboembolism. Common risk factors include small caliber artery, peripheral vascular disease, the use of larger size sheaths, low cannulation into the superficial femoral or profunda femoris artery, the use of a vascular closure device with intraarterial components (such as Angio-Seal), or a sheath that is left behind for a prolonged period of time. In addition, digital ischemia may be due to cholesterol emboli ( Figure 3-12 ). Classic signs and symptoms include the five P's: pain, pallor, paresthesia, pulselessness, and paralysis. Diagnosis is by Doppler ultrasonography studies. Angiography is needed to localize the site of occlusion. Treatment includes anticoagulation, contralateral access, and angiography, with thrombectomy and possible angioplasty or stenting, or intraarterial fibrinolytic administration. In some cases surgical thrombectomy with vascular bypass grafting may be required. In rare cases ischemic complication can be due to the use of a vascular closure device such as Perclose or the Angio-Seal ( Figure 3-13A-C ). In addition to dislodgment of plaque by the footplate of these devices, intraarterial deposition of collagen (with Angio-Seal) or subintimal dissection of the common femoral artery (with Perclose) has been described as the etiology of ischemic complications.

Dissection

Femoral artery dissection is a rare (0.2%-0.4%) complication of femoral artery cannulation. Risk factors include presence of atherosclerosis in the CFA or the external iliac artery, vessel tortuosity, and dissection during advancement of the guidewire or during femoral angiography. Diagnosis is made during femoral angiography and most patients are asymptomatic. In rare cases the patient presents with symptoms and signs of ischemic limb after the sheath is removed. Treatment includes observation as most dissections are retrograde and spontaneously heal. In rare cases if ischemic complications arise, contralateral access and angiography and possible angioplasty or stenting or surgical repair should be considered.

Femoral Neuropathy

Femoral neuropathy is due to injury to the femoral nerve during access and/or compression of the femoral nerve by a hematoma or pseudoaneurysm. The incidence is around 0.2%. Patients present with pain/paresthesia at the femoral access site with radiation down the limb or with leg weakness. Physical examination may reveal focal neurological signs including decreased sensory perception, decreased motor strength, or decreased patellar tendon reflexes. Treatment should be aimed at the underlying cause (hematoma/pseudoaneurysm), treatment of symptoms, and physical therapy.

Groin Site Infection

Access site infection is rare (<0.1%) but can be potentially serious resulting in sepsis. Risk factors include obesity with folds of adipose tissue at the access site, presence of superficial infection at the site of entry, diabetes mellitus, compromised sterile technique during access or closure, prolonged indwelling sheath time, and use of a vascular closure device. Patients present with pain, swelling, discharge at the access site, fever, and/or an increase in the white blood cell count. Treatment includes administration of antibiotics and symptomatic treatment for pain relief. In rare case and especially when a vascular closure device is used, surgical debridement with removal of any indwelling component of the closure device may be necessary. Infection associated with the vascular closure device is an extremely serious complication that requires aggressive medical and surgical intervention and carries high rates of morbidity and mortality. The majority of patients with infection present 7 to 10 days after deployment of the device and need prolonged antibiotic therapy (up to 28 days) and arterial debridement and reconstruction.