Abstract:
Appropriate and safe vascular access and hemostasis are essential for cardiac catheterization procedures, and careful technique is critical. Key steps must be followed throughout the entire process, from preprocedure to recovery, requiring a cooperative effort of the whole team. For arterial access, femoral and radial approaches are most commonly used. The radial approach offers advantages of improved patient comfort and reduction in bleeding and vascular complications, resulting in an increased use of radial access in the past several years. For venous access, femoral and internal jugular approaches are most commonly used. Routine ultrasound imaging for vascular access has been demonstrated to increase the success of the first access attempt, reduce the number of attempts needed to gain access, and reduce access-site complications.
Keywords:
femoral artery, radial artery, arterial access, venous access, cardiac catheterization
Vascular access
A critical part of any catheterization procedure is attaining proper vascular access. Arterial access can be obtained in the femoral, brachial, or radial arteries. Preprocedure planning, careful detail to technique, proper equipment, and operator skill are all highly important. Some of the critical points of vascular access may not seem important to the uninitiated, but they are crucial to the safety and success of the procedure. The site of access is determined by planned investigation and the anticipated anatomic and pathologic conditions of the patient, in addition to anticipated bleeding risk. If possible, previous procedures and any difficulties encountered therein should be reviewed from old reports. Preprocedural assessment of the quality of all peripheral pulses is mandatory.
For patient comfort, adequate premedication and generous local anesthesia should be administered using a gentle approach. Pain during entry into the vessel may cause a vagal reaction or arterial spasm, potentially prolonging the procedure and causing significant complications.
Arterial access site selection
For arterial access, femoral and radial approaches are most commonly used. Historically, brachial access was employed, but observed complication rates were relatively greater. A comparison of femoral versus radial artery catheterization is provided in Table 2.1 . The greatest advantage of the radial approach is a reduction in bleeding and vascular complications, which has also been associated with a mortality benefit in high-risk patients. Because of this advantage, use of radial access in the United States has risen dramatically in the past few years. In 2007, 1.3% of all percutaneous coronary interventions (PCIs) were performed via the radial artery, but radial PCI had increased to >35% by 2017 ( Fig. 2.1 ).
| Feature | Femoral | Radial |
|---|---|---|
| Access site bleeding | 3%–4% | 0%–0.6% |
| Artery complications | Pseudoaneurysm, retroperitoneal bleed, AV fistula, hematoma | Rare local irritation, pulse loss 3%–9% |
| Patient comfort | Acceptable | Excellent |
| Ambulation | 1–4 hours | Immediate |
| Extra costs | Closure device (optional) | Hemostasis Band |
| Procedure time | Perceived shorter | Perceived longer |
| Estimated radiation exposure | Perceived lower | Perceived higher |
| Access to LIMA | Typically straightforward | Difficult from right radial artery |
| Use of artery for CABG surgery | N/A | Unknown |
| Learning curve | Short | Longer |
| >8-F guide catheters | Typically not a problem | Maximum 7 F (in men) |
| PVD, obese | Possibly problematic | Less problematic |
Femoral artery access
Percutaneous femoral arterial catheterization is still the most widely used technique in the United States. However, in patients with a history of claudication, signs of chronic arterial insufficiency, diminished or absent pulses, or bruits over the iliofemoral area, an alternate entry site may be considered to avoid the risk of further impairment of the arterial circulation in the legs ( Box 2.1 ). The presence of arterial conduit grafts or previous balloon angioplasty of the iliofemoral system is not an absolute contraindication to femoral artery access. Prosthetic graft puncture has been shown to be safe if small-diameter sheaths are used and careful management for hemostasis is followed at the end of the procedure. Nonetheless, an alternative route should be considered.
Claudication
Absent dorsalis pedis and posterior tibialis pulses
Absent popliteal pulses
Femoral bruits
Absent femoral pulses
Prior femoral artery graft surgery
Extensive inguinal scarring from radiation therapy, surgery, or prior catheterization
Excessively tortuous or diseased iliac arteries
Severe back pain, inability to lie flat
Patient request
Morbid obesity
Artery location
Femoral artery access is usually obtained using the patient’s right femoral artery with the operator standing at the right side of the patient. The common femoral artery is defined as that portion of the femoral artery below the lowest margin of the inferior epigastric artery and above the bifurcation of the superficial and profunda branches of the femoral artery. The goal is to access the common femoral artery over the mid portion of the femoral head so that there is a hard surface against which to compress the femoral artery when achieving hemostasis ( Fig. 2.2 ). The mid portion of the femoral head is located approximately 2 cm below the inguinal ligament. The inguinal ligament is located by palpating the anterior superior iliac spine and the pubis and drawing an imaginary line between them. Then, using the middle and index fingers placed parallel to the long axis of the femoral artery, find the arterial pulse ∼2 cm below this imaginary line ( Fig. 2.3 ). A metal clamp can also be placed over the proposed entry site and the site can be confirmed by fluoroscopy ( Fig. 2.4 ). Some operators place the tip of the clamp at the lower border of the femoral head to indicate where they will numb the patient and then angle their needle such that they access the artery approximately 1 cm above this skin entry location. Identification of the femoral artery based on the skin crease as an anatomic landmark is no longer advocated because of its variability, particularly in obese patients.
Local anesthesia
With a 25-gauge needle, the skin is infiltrated superficially with 1% lidocaine ∼1 cm below (caudal to) the desired arterial entry site. This point is the skin entry site. In obese patients with thick subcutaneous tissue, the entry site should be slightly lower to ensure a needle entry angle of 45 degrees or less. Because large amounts of lidocaine may obscure the pulse, inject small amounts repeatedly instead of administering a large bolus. Next, with a 21-gauge needle, introduce 1% lidocaine into the deep tissue planes on each side of the artery. During lidocaine infiltration, palpate the arterial pulse with the middle and index fingers to avoid accidental puncture of the artery and ensure infiltration of tissue above and around the artery.
Gentle aspiration before the injection of lidocaine is essential to ensure that the needle tip is not in a blood vessel. Inserting the needle first to the deepest level desired and then continuing infiltration at several more shallow layers may decrease the patient’s discomfort. Local anesthesia should cover the whole depth of the expected skin-to-artery path. Give sufficient lidocaine (∼15 to 20 mL of a 1% solution) over 2 to 3 minutes for the full anesthetic effect to take place. Hint: Give lidocaine early and while the anesthetic is taking effect, other preparations such as connecting tubing and flushing catheters can be completed. During access, listen to the heart rate monitor or watch the electrocardiogram (ECG) for slowing of the rate as an early warning of a vagal reaction. Alternatives to lidocaine are listed in Box 2.2 .
Group I
Procaine (ester prototype)
Benoxinate (Dorsacaine), benzocaine, butacaine (Butyn), butethamine (Monocaine), butylaminobenzoate (Butesin), chloroprocaine (Nesacaine), procaine (Novocain), tetracaine (Pontocaine)
Group II
Lidocaine (amide prototype)
Amydricaine (Alypin), bupivacaine (Marcaine), cyclomethycaine (Surfacaine), dibucaine (Nupercaine), dimethisoquin (Quotane), diperodon (Diothane), dyclonine (Dyclone), etidocaine (Duranest), hexylcaine (Cyclaine), mepivacaine (Carbocaine), oxethazaine (Oxaine), phenacaine (Holocaine), piperocaine (Metycaine)
Pramoxine (Tronothane), prilocaine (Citanest), proparacaine (Ophthaine), pyrrocaine (Endocaine)
Skin entry and access channel preparation
Some operators perform a small skin incision before inserting a Seldinger needle. Other operators prefer to nick the skin over the entry needle or guidewire after the puncture. The latter approach usually results in only one nick if the operator does not obtain access on the first attempt. With the fingers placed over the artery as described previously, the operator can make a skin incision of 2 to 3 mm with a scalpel blade. For large-diameter sheaths, a subcutaneous tunnel can be made with blunt dissection using forceps. This channel makes the catheter and sheath entry easier and permits blood to drain outside the leg if the puncture site bleeds after the catheters have been removed. It is important to avoid extensive disruption of skin and subcutaneous tissue while creating the channel because these are the natural barriers to infection.
Arterial puncture
The single anterior arterial wall entry (modified Seldinger) technique is preferred for femoral artery access ( Fig. 2.5 ). This is especially important in patients treated with anticoagulants, antiplatelet agents, or thrombolytic agents. Access can be performed with a micropuncture kit or 18-gauge multipurpose needle. Ultrasound may be used to examine vessel size and the presence of untoward plaque and to identify the common femoral artery, thus avoiding puncture of bifurcations. Furthermore, ultrasound-guided access has been shown to facilitate anterior wall entry.
The original Seldinger double-wall puncture technique is not explained here. The single-wall technique begins with the operator’s fingers positioned over the femoral artery as described earlier. Hold the arterial needle (without an obturator) with the tip of the bevel directed upward. Introduce the needle through the skin and advance slowly toward the artery at a 30- to 45-degree angle to the horizontal plane. An entry into the artery that is too vertical creates problems in advancing the guidewire and promotes sheath and catheter kinking. A pulsation may be felt when the needle contacts the arterial wall. A slight resistance to the needle can be felt as it passes through the arterial wall. At this point, blood return from the needle hub confirms arterial puncture. Maintain the intraarterial needle position by holding the needle hub in a stable position. Resting the wrist on the patient’s thigh may be helpful to stabilize needle position.
If the artery is not accessed, completely withdraw the needle, flush it of clot or fat, and advance in a different direction. Because of the sharp edge of the needle used for single-wall entry, the direction of the needle should not be changed when the needle tip is in the subcutaneous tissue.
Guidewire insertion
Advance the guidewire gently into the artery. A soft J-tipped guidewire is the safest. Although straight-tipped guidewires have been used, they may increase the potential for subintimal dissection or vessel perforation. The wire should advance freely, without resistance. If resistance is encountered, the wire may be pulled back and advanced under fluoroscopic guidance, or the wire may be pulled back completely to confirm needle position via pulsatile blood return. Repositioning the needle may be necessary if the wire cannot be advanced freely. Sometimes the needle tip partially penetrates the posterior wall. In this case, there is good blood return, but the wire cannot be advanced because it is directed into the posterior wall of the artery rather than the arterial lumen. Withdrawing the needle 1 to 2 mm usually solves this problem. Lowering the needle hub several millimeters, or moving it medially or laterally, may improve alignment of the needle tip with the artery and permit easier guidewire passage. However, to avoid arterial injury, it is important not to move the needle hub excessively in any direction. The operator should attempt to puncture the artery close to the midline of the anterior vessel wall. Puncturing the lateral arterial wall may create a problem in advancing the guidewire or, worse, in controlling bleeding after the procedure.
If it is not possible to advance the wire or if the needle comes out of the artery, withdraw the needle from the skin and apply pressure over the puncture site for at least 2 minutes to ensure hemostasis. Repeat the procedure using a slightly different angle or direction.
Micropuncture access
The use of a 21-gauge micropuncture needle to obtain femoral artery access is appealing, because less bleeding may occur and hemostasis may be more easily achieved following needle removal compared with the use of larger gauge needles. This technique involves placement of a small micropuncture sheath into the femoral artery over a micropuncture guidewire once access has been obtained. The dilator of the micropuncture sheath can then be removed and the micropuncture sheath can be exchanged for a larger sheath over a 0.035-inch guidewire. However, micropuncture technique has not been proven to be superior to standard technique in preventing bleeding complications.
Ultrasound imaging
If the artery cannot be located by palpation, ultrasound imaging can be used to localize and enter the artery ( Fig. 2.6 ). A Doppler-tipped needle (Smart Needle), which differentiates between high-pitched (arterial) or low-pitched (venous) flow velocity sounds, can also be used.
Routine ultrasound imaging may be useful in visualizing the femoral artery bifurcation and ensuring that access is obtained above the bifurcation in the common femoral artery. In addition, ultrasound imaging can be used to identify (and avoid) areas of atherosclerosis and/or vessel calcification ( Fig. 2.7 ). Routine ultrasound imaging has been shown in large trials to increase the success of the first access attempt (83% vs. 46%, P <0.001) and thereby reduce the number of attempts needed to gain access and the time to arterial access. Furthermore, complications such as inadvertent venipuncture and access site hematoma are reduced with routine ultrasound imaging. The depth penetration should be adjusted to visualize the femoral artery and vein, and the centerline guide should be turned on. The femoral artery is imaged in the axial plane by holding the probe perpendicular to the course of the artery. The artery pulsates with gentle compression. Align the artery with the centerline guide on the display and insert the needle directly underneath the center marking of the probe, as close to the probe as possible. Using short in-and-out movements to visualize the needle course, move the needle toward the artery until it eventually compresses the artery and then punctures through.
From guidewire to catheter insertion
If no resistance is encountered, advance the guidewire several centimeters at first and then into the abdominal aorta using fluoroscopy. Fluoroscopy of the guidewire moving through the iliac artery identifies large arterial plaques and excessive tortuosity, which complicates later catheter manipulation. As noted earlier, use of a J-tipped soft-spring guidewire is recommended because a straight wire may pass under a plaque, resulting in dissection. After the guidewire is correctly positioned above the iliac artery, remove the arterial needle. Apply firm pressure over the puncture site (to control bleeding) with the fingers while removing the needle from the skin and maintain puncture site pressure. The guidewire should be held firmly to avoid accidental wire removal as the needle is taken off the guidewire from the artery.
Advancement of the sheath
After guidewire insertion into the artery, advance the sheath-dilator assembly over the wire while holding the guidewire straight. Introduce the sheath-dilator assembly into the artery by firmly holding it close to the tip, making clockwise and counterclockwise half-rotations (to reduce forward friction), and applying firm forward pressure. The sheath should not be advanced if significant resistance is encountered, as in the case of scar tissue. If significant resistance is encountered, serial dilatation of the tissue tract with increasingly larger dilators can be performed before the final sheath is inserted. The guidewire should be held straight and taut because it may otherwise kink. After the sheath is inserted completely, hold the sheath hub firmly in place and remove the dilator and guidewire together. Aspirate 2 to 3 mL of blood from the side arm of the sheath and flush the sheath with heparinized saline solution. The arterial pressure can be checked immediately by connecting a pressure manifold to the side arm of the sheath.
Patient awareness
For both radial and femoral access, three steps may be associated with pain and vagal reaction: (1) initial administration of lidocaine, (2) arterial needle insertion, and (3) sheath assembly advancement. The operator should monitor the heart rate and feel the strength of the arterial pulse to detect early vagal responses. A vasovagal reaction of hypotension can occur with no change in heart rate, most commonly in elderly patients.
Sheath removal and manual pressure hemostasis
After catheterization has been completed, the patient’s blood pressure is monitored and the catheter is removed. The sheath is aspirated and flushed to clear any thrombi. If heparin has been given during the procedure, an activated clotting time (ACT) should be obtained. Protocols vary, but the sheath is generally not removed until the ACT falls below 200 s. To remove the sheath, the operator places his or her fingers over the femoral artery. Because the actual puncture site is more cranial (toward the patient’s head) than the skin incision, the operator’s fingers should be placed over the femoral artery above the skin puncture site. The operator applies gentle pressure and removes the sheath from the leg, taking care not to crush the sheath and strip clot into the distal artery. When a small spurt of blood purges the arterial site of retained thrombi, the operator should apply firm downward pressure. Firm three-finger pressure should be adequate to achieve hemostasis in most cases. A rolled gauze pack may be placed over the artery to the groin and pressure applied with the palm of the hand. Standing on a short stool at bedside permits the operator’s upper body weight to be used for pressure application.
Manual pressure is held firmly for approximately 3–5 minutes per sheath size, i.e., 15 to 25 minutes for a 5-F sheath and 18 to 30 minutes for a 6-F sheath. In patients treated with antiplatelet therapy, longer puncture site compression may be necessary. Compression time should be divided into four periods: full pressure, three-quarters pressure, half pressure, and one-quarter pressure, over the prescribed duration. During pressure application, pedal pulses should be intermittently evaluated and the entire leg should be uncovered to identify duskiness of the extremity. A diminished pulse is acceptable during brief full-pressure application, but distal pulses should not be obliterated completely at any time during manual compression. If the pedal pulse is absent during compression, the pressure over the artery should be decreased slightly periodically to allow distal circulation. Complete artery occlusion prevents clotting factors and platelets from being deposited at the arterial wall puncture site and in extreme cases can lead to vessel thrombosis, particularly in lower extremity bypass grafts. In patients with low cardiac output and a narrow pulse pressure, the femoral artery can easily be obliterated. In these patients, distal pulses should be checked more often and less pressure should be applied to the groin.
Hematoma monitoring and groin dressings
After an appropriate time for manual pressure, the operator’s hand is removed slowly and the area is inspected for hematoma or bleeding. Hemostasis may be difficult to secure in obese, hypertensive, or elderly female patients. Likewise, hemostasis may take longer to achieve in patients with a coagulopathy or who are receiving anticoagulant or antiplatelet agents. In all such patients, an extended monitoring period is prudent. In larger patients, greater than 500 mL of blood can be lost in a thigh or pannus before the problem is identified.
After hemostasis is obtained, clean the puncture area with an antiseptic solution and apply a small clear sterile dressing (e.g., Opsite, Tegaderm). This permits visualization of the entry site and surrounding tissues. One should not use gauze under the plastic dressing because this forms a culture medium if left in place after discharge. Likewise, large pressure dressings or sandbags should not be used, because they are ineffective in preventing bleeding and obscure the puncture site so that early hematoma formation may be missed.
If the femoral artery and vein are used in the procedure, arterial hemostasis should first be ensured and then the venous sheath should be removed to decrease the risk of AV fistula formation. In addition, preservation of venous access for the first 15 minutes of arterial compression may provide a useful access to treat hypotension resulting from blood loss or a vagal reaction should the peripheral IV line be inadequate for large volume resuscitation.
Mechanical compression and vascular closure devices
FemoStop pressure system
The FemoStop ( Fig. 2.8 ) is an air-filled clear plastic compression bubble that molds to skin contours. It is held in place by straps passing around the hips. The amount of applied pressure is controlled with a sphygmomanometer gauge. The clear plastic dome allows the operator to see the puncture site. The FemoStop is used most often for patients in whom prolonged compression is anticipated or whose bleeding persists despite prolonged manual compression. The duration of FemoStop compression and time until removal of the device vary depending on the patient and staff protocols. In some hospitals, the time from application to removal may be less than 30 minutes. In other patients in whom hemostasis is required, the device may be left at lower pressures for a longer duration. During the entire time of placement, direct visualization and monitoring should be performed by a trained individual. Caution should be used not to apply too much pressure to the groin, particularly for long durations, which may increase the risk of arterial or deep venous thrombosis.
Vascular closure devices
Several different types of vascular closure devices (VCDs) are currently available. All VCDs have demonstrated rapid hemostasis and a decreased time to ambulation when compared with manual compression, but none has been shown to decrease vascular complications in randomized controlled trials. These devices may be especially helpful in patients who have back pain or cannot lie flat. Active closure methods include suture type (Perclose Proglide, Abbott Vascular, Santa Clara, CA), extravascular plug (Angio-Seal, St. Jude Medical, Santa Clara, CA; Mynx, Abbott Vascular, Santa Clara, CA), and surgical staple/clip technology (Abbott Vascular, Santa Clara, CA, Cardinal Health, Dublin OH; EVS-Angiolink, Medtronic, Inc., Minneapolis, MN). Theoretically, Angio-Seal has a higher risk of thromboembolic events because of the intravascular collagen anchor. The suture-mediated devices use primary healing (end-to-end anastomosis at the arteriotomy site) but have the highest rate of device and operator failure because of the learning curve associated with their use. Because VCDs do not ensure freedom from bleeding or vascular complications, diligent monitoring is still essential. The advantages and disadvantages of the various arterial closure devices are summarized in Table 2.2 .
All VCDs should be used with caution in patients with peripheral vascular disease or with a high (above upper third of the femoral head) or low (at or below the femoral bifurcation) arterial puncture. Suture-mediated devices should not be used in small arteries (<4 mm). Caution is also needed in patients with scar tissue at the site of prior femoral artery procedures. Femoral angiography with an ipsilateral oblique angle (i.e., right anterior oblique [RAO] for right femoral artery, left anterior oblique [LAO] for left femoral artery) lays out the bifurcation, although the sheath entry site is often obscured. On the other hand, the contralateral oblique angle nicely demonstrates the sheath entry site but obscures the bifurcation ( Fig. 2.9 ). The ipsilateral oblique angle is generally preferred and then the sheath is gently pulled medially to determine its entry point. For patient comfort, and to minimize contrast administration, femoral angiograms can be performed with a 50/50 contrast mixture.
Postcatheterization patient instructions and discharge
Depending on the catheter and sheath size and whether or not a VCD was used, bed rest is recommended for 1 to 4 hours after femoral artery puncture. In the recovery area, the patient is instructed (1) to stay in bed, (2) to keep the head down, (3) to hold the groin site when coughing, (4) to keep the punctured leg straight, and (5) to call a nurse for assistance if there is any bleeding, leg numbness, or leg pain. Following bed rest, the patient can sit up in bed for 30 minutes and can then walk with nursing assistance. At this point, the groin is rechecked and if there is no sign of hematoma or bleeding, the discharge process can continue.
Radial artery access
The radial artery is easily accessible in most patients and is not located near significant veins or nerves ( Fig. 2.10 A). The superficial location of the radial artery enables easy access and control of bleeding. No significant clinical sequelae after radial artery occlusion occur in patients with a normal Allen or Barbeau test because of the dual blood supply to the hand through the ulnar artery (see Fig. 2.10 B). Lastly, patient comfort is enhanced by the ability to sit up and walk immediately after the procedure.
