The Access Site

Endovascular intervention begins with vascular access. Appropriate vascular access requires the site to provide a secure, direct, and uninterrupted pathway to the vascular bed of interest or target lesion. The commonly used arterial access sites are the common femoral arteries in the groins and the brachial arteries at the antecubital fossae (Figure 17-1). The femoral approach from the right groin is usually the first choice for angiography and most interventions (Figure 17-2). Its superficial location allows for ease of access, and its relatively large caliber provides blood flow around the sheath to maintain perfusion to the distal lower extremity. In addition, the common femoral artery lies anterior to the femoral head, providing support for pressure to achieve hemostasis should the need arise. This access can be directed in a retrograde fashion toward the pelvis or antegrade toward the thigh. The retrograde femoral puncture provides access to the entire thoracoabdominal aorta and its branches. The contralateral iliofemoral arteries and lower extremity circulation can be easily catheterized from this approach. Alternatively, using an antegrade femoral puncture, distal arteries such as the infrapopliteal and inframalleolar circulation can be visualized in detail and treated most directly.

FIGURE 17-1 Sites for arterial access.

(From Moore WS, Ahn SS, editors: Endovascular surgery, ed 4, Philadelphia, 2011, Saunders, p 50.)

FIGURE 17-2 Common femoral artery puncture. A, Entry into common femoral artery. B, Maintenance of access with passage of guidewire.

(From Moore WS, Ahn SS, editors: Endovascular surgery, ed 4, Philadelphia, 2011, Saunders, p 50.)

Arterial puncture in the upper extremity also provides access to thoracoabdominal aorta and its branches. The use of upper extremity access is usually limited to instances in which the common femoral arteries are not available because of occlusive disease in the aortoiliac segment or recent bypass. The left brachial artery is preferably used because the left subclavian artery is a separate branch from the left common carotid artery off the aortic arch. A sheath from the right brachial artery can also be used. It has a potential disadvantage in that it crosses the origin of the right common carotid artery (and also the left common carotid artery in bovine arch) as it enters the aortic arch. This can increase the risk of embolization to the brain from atherosclerotic plaque in the diseased innominate artery during sheath and catheter manipulations or device delivery. The axillary artery is contained in a neurovascular sheath, and even minimal bleeding in the sheath has the potential to cause nerve compression with resultant upper extremity paralysis. Therefore the axillary artery is not routinely used as an arterial access. The radial artery is frequently used for cardiac interventions; devices deliverable through a 6-French sheath can be used through specially designed radial sheaths, but access at the wrist necessitates very long catheters and devices for imaging or intervening in the infrainguinal vasculature. The advantages and disadvantages of the various access sites are listed in Table 17-1.

TABLE 17-1 Comparison of Sites for Arterial Access

For venous interventions, common access sites are the femoral veins in the groins, brachial veins at the antecubital fossa, and popliteal veins behind the knee. In the treatment of deep venous thrombosis with thrombolytic therapy or endovascular mechanical thrombectomy, the contralateral femoral vein is recommended. Although venous valves are a potential impediment for catheter advancement from an up and over approach, it is not difficult to overcome this impediment with guidewire and guide catheter advancement techniques. Using this approach, a removable inferior vena cava (IVC) filter can be placed before catheterization and treatment of the diseased vein in the lower extremity. Simultaneous access of the popliteal vein may also be used to cross the venous lesion. With the leg externally rotated at the hip, ultrasound guidance can be used to locate and access the popliteal vein behind the knee with the patient in the supine position.

In diagnostic venograms, the superficial veins of the upper and lower extremities can be used. In the upper extremities, the cephalic or the basilic veins are used. In the lower extremities, superficial veins on the dorsum of the foot are cannulated and venous tourniquets are used to direct contrast into the deep system.

Vascular Cannulation

Vascular cannulation is a standardized procedure that is applied regardless of the vein or artery selected. There are two methods to obtain vascular access (Figure 17-3): the through-and-through puncture and the single-wall puncture. In the through-and-through (double-wall) method, both the anterior and posterior walls are completely crossed with the needle. The needle is then withdrawn back into the lumen. This is sometimes used for venous entry, but is not recommended routinely for arterial access. The posterior wall puncture can lead to bleeding complications such as retroperitoneal hematoma at the groin or nerve compression in the surrounding perivascular spaces. The posterior wall puncture can also lead to arteriovenous fistula. For arterial access, the single-wall puncture is preferred. A steady pressure is applied to slowly advance the needle. Pulsatile flow after puncture of only the anterior wall indicates entry into the arterial lumen.

FIGURE 17-3 Vascular cannulation. A, Through-and-through (double-wall) puncture. B, Anterior (single-wall) puncture.

(From Moore WS, Ahn SS, editors: Endovascular surgery, ed 4, Philadelphia, 2011, Saunders, p 52.)

The Seldinger technique is the fundamental method of vascular access that was first described in 1953 (Figure 17-4). A wire, needle, and a sheath are required. In this technique:

FIGURE 17-4 The Seldinger technique. A, Angulated entry into the vascular wall. B, Guide wire is then passed through the needle into the vascular lumen. C, The needle is removed and exchanged for the appropriate sheath over the guide wire.

(From Moore WS, Ahn SS, editors: Endovascular surgery, ed 4, Philadelphia, 2011, Saunders, p 52.)

For safe vascular access, especially the small arteries such as the brachial artery at the antecubital fossa, a modified Seldinger technique using the micropuncture set is recommended (Figure 17-5). A small, 21-gauge needle is used to obtain vascular entry. A 0.018-inch guidewire is inserted to secure access, followed by exchange of the needle for a paired coaxial catheter. The small inner catheter accepts the small guidewire and functions as a dilator for the larger outer catheter. The small guidewire and catheter are both removed, and a 0.035-inch guidewire is inserted into the outer catheter. This catheter is then removed for the appropriate sheath. It is common to use ultrasound guidance for real-time vascular wall imaging, in addition to routine reliance on micropuncture technique.

FIGURE 17-5 Micropuncture kit.

(From Bard Access System, Salt Lake City, Utah.)

Retrograde Femoral Puncture

The common femoral artery can be located using the osseous anatomic landmarks at the groin (Figure 17-6). In general, there is approximately 3 to 5 cm of common femoral artery located anterior to the junction of the medial third and middle third of the femoral head. This artery begins proximally at the inguinal ligament and is two fingerbreadths lateral to the pubic symphysis on a line joining the symphysis with the anterior iliac spine. This relationship varies little with the patient’s body habitus and age; however, the location of the inguinal ligament and the common femoral artery can be misleading in obese patients. The abdominal panniculus may falsely lead the interventionalist to initiate access more distally, resulting in puncture of the superficial femoral or profunda femoris arteries. Before entry with the needle, the femoral head should first be identified with the fluoroscopy. Inadvertent access of these arteries increases the risk of postoperative hematoma, pseudoaneurysm, or arteriovenous fistula. Using ultrasound to identify the common femoral artery and the profunda femoris and superficial femoral artery origins, at the time of microneedle insertion, reduces these types of complications.

FIGURE 17-6 Retrograde femoral puncture. Localization of the common femoral artery using the osseous anatomic landmarks at the groin.

(From Moore WS, Ahn SS, editors: Endovascular surgery, ed 4, Philadelphia, 2011, Saunders, p 53.)

To access the common femoral artery, the surgeon needs to locate the inguinal ligament and be familiar with the relation between skin puncture site, angle of needle entry, and the femoral head. Once there is pulsatile blood return at the needle hub, the guidewire is passed to secure the intraluminal location. Fluoroscopy can be used to verify the location of the needle tip. If the tip is below the femoral head, puff contrast arteriography is performed with the image intensifier in an ipsilateral oblique position to confirm access of the common femoral artery. This view allows for visualization of the common femoral bifurcation and the proximal superficial femoral or profunda femoris arteries. If the arterial puncture is satisfactory, the guidewire is advanced under fluoroscopic guidance.

Antegrade Femoral Puncture

The antegrade femoral puncture is a useful arterial access for intervention of distal, ipsilateral arterial lesions. This is especially true for tall patients with distal tibial arterial lesions, where there may not be enough catheter length for the angioplasty balloon or stent to reach the target from a contralateral, retrograde femoral puncture. In this technique, the needle is inserted just distal to the anterior iliac spine in an antegrade fashion to access the common femoral artery (Figure 17-7). Similar to retrograde femoral puncture, the location of the inguinal ligament can be misleading in obese patients, resulting in puncture of the superficial femoral or the profunda femoris arteries. In these patients, the abdominal panniculus is retracted in a cephalad direction to allow for appropriate location and angle of needle entry at the skin. The location of the femoral head should be identified with fluoroscopy before skin puncture. Less commonly, the needle may access the external iliac artery; this results in difficulty with guidewire advancement and postoperative bleeding complications (Figure 17-8). Ultrasound guidance should be used routinely.

FIGURE 17-7 Antegrade femoral puncture. Localization of the anterior superior iliac spine pubic symphysis. The needle is inserted just distal to the inguinal ligament.

(From Moore WS, Ahn SS, editors: Endovascular surgery, ed 4, Philadelphia, 2011, Saunders, p 54.)

FIGURE 17-8 External iliac artery access during antegrade puncture. Potential difficulty with guide wire advancement and postoperative bleeding complications.

(From Moore WS, Ahn SS, editors: Endovascular surgery, ed 4, Philadelphia, 2011, Saunders, p 54.)

With antegrade femoral puncture, the guidewire is frequently advanced into the profunda femoris artery. Under fluoroscopic guidance, the needle tip may be moved either medially or laterally to redirect it into the superficial femoral artery. However, this may not be possible if the needle access is too close to the femoral bifurcation. For antegrade punctures, the needle should enter the proximal common femoral artery as close to the femoral head and the inguinal ligament as possible. As mentioned previously, the use of the micropuncture kit is recommended. If the wire is advanced into the profunda femoris artery, the needle is exchanged over wire with the outer sheath in this artery. Contrast is injected through the sheath as it is pulled back until the tip is in the common femoral artery under fluoroscopy. An angled guidewire is then advanced into the superficial femoral artery (Figure 17-9).

FIGURE 17-9 Redirecting the wire and catheter from the profunda femoris to the superficial femoral artery.

(From Moore WS, Ahn SS, editors: Endovascular surgery, ed 4, Philadelphia, 2011, Saunders, p 55.)

Another technique is to sequentially exchange the micropuncture needle over wire to a 6-French sheath. With a 0.014-inch wire in the profunda femoris artery to maintain arterial access, the sheath is pulled back while contrast is injected until the tip is in the common femoral artery. A second, angled guidewire is passed through the sheath and advanced into the superficial femoral artery. The 0.014-inch wire is removed from the profunda femoris artery, and the sheath is advanced over the dilator and guidewire.

Ultrasound Guided Access

A small and portable ultrasound unit such as the Sonosite (General Electric, Bothell, Wash.) can be used to identify and characterize the artery or vein to be accessed (Figure 17-10). The common femoral artery or vein can be located at the groin, the brachial artery or vein at the antecubital fossa, and the superficial veins in the upper or lower extremities. The ultrasound is especially useful when the vascular structure cannot be palpated because of occlusive disease or patient obesity. Under ultrasound imaging, the echogenic tip of the micropuncture needle can be seen as it passes deep into the soft tissue and enters the anterior wall of the artery or vein. In addition, a soft spot in a diseased arterial wall can be identified and entered with needlepoint accuracy.

FIGURE 17-10 Ultrasound guided vascular access. A, Localization of artery with ultrasound. B, Ultrasound guided access using real-time imaging.

(From Moore WS, Ahn SS, editors: Endovascular surgery, ed 4, Philadelphia, 2011, Saunders, p 56.)

For access of the common femoral artery, the artery is first identified at the groin. The ultrasound probe is moved in a cephalad direction to image the artery until it dives deep to become the distal external iliac artery at the inguinal ligament. This is the anatomic landmark for the beginning of the proximal common femoral artery. The probe is then moved in a caudal direction to locate the origin of the superficial femoral and profunda femoris arteries. This is the landmark for the distal common femoral artery at the bifurcation. While the entire common femoral artery is being imaged, attention is given to any potential plaque on the posterior wall or calcification on the anterior wall. These lesions are avoided, and the arterial entry site should be made proximal to these lesions if possible. Once a spot on the anterior arterial wall is selected, skin entry of the needle is made approximately 1 or 2 cm away from the probe to provide a gentle angle of access into the artery. There is a learning curve to this technique, and the surgeon needs to keep in mind the relationship between the skin puncture sites, angle of needle access, and the depth of the artery as imaged. This technique is used for both antegrade and retrograde femoral punctures.

For access of the brachial artery, the artery is first identified at the antecubital fossa. The artery is imaged in a proximal and distal direction to select the location where it is most superficial, and to note the location of the brachial bifurcation. The probe is then lightly placed on the skin, and the artery is imaged again to visualize any potential crossing basilic or antecubital veins overlying the artery. Puncture of the vein and artery is avoided to prevent iatrogenic arteriovenous fistula. The median nerve may also be identified and avoided.

With mastery of this technique, a surgeon will be able to access vascular structures that might not otherwise be safely or easily cannulated. Access complications can be limited by verifying position, avoiding focal plaque, and directing the needle to a healthier arterial segment. The micropuncture technique and ultrasound-guided access can be used for all vascular cannulations. Other than the slight increase in procedure time required during the learning phase, there are no credible arguments against routine use of this technique.

Hematoma

Groin hematoma remains one of the most common complications following endovascular procedures. Predisposing factors include the use of anticoagulants during procedure, periprocedural antiplatelet medications, size of access device, surgeon’s experience, and type of procedure being performed. Blood from a femoral artery usually collects in the external genitalia, flank, or thigh, and ecchymosis is typically minimal immediately after the procedure but may become significant in the hours following completion. In patients taking anticoagulation and antiplatelet medications, ecchymosis may be more extensive with discoloration extending upward onto the lower abdomen or below onto the thigh and flank as the patient ambulates. Bleeding from the brachial artery may have ecchymosis involving much of the arm.

Symptoms of a hematoma can vary from mild discomfort to severe pain with attendant swelling. Small hematomas rarely lead to severe complications, but large hematomas can result in significant blood loss with hypotension and significant physiologic derangement. Pressure and tension from the mass effect can cause skin necrosis with compression and irreversible nerve injury. The extent of a hematoma can be elucidated with computed tomography; this entails additional radiation and contrast exposure and is not routinely employed, but it may be useful in identifying retroperitoneal hemorrhage associated with the access that is otherwise not externally visible.

When a hematoma is suspected, manual pressure should be applied to prevent further bleeding. Urgent surgical evacuation with repair of the vessel may be necessary to prevent shock and life-threatening complications if direct pressure is inadequate to achieve hemostasis. Other surgical indications include severe pain, nerve compression, venous obstruction, and skin necrosis. After the skin incision is made over the hematoma, dissection is made through the fascial planes to the artery. Usually, one or two interrupted sutures are all that is needed to repair the vessel.

Several factors can assist in the prevention of hematomas. During access, it has been found that needle access 1 cm lateral to the most medial cortex of the femoral head and proper maintenance of a 30- to 45-degree puncture angle can reduce the likelihood of groin hematoma formation.⁷ At the time of sheath removal, hypertension control and coagulation status of the patient should be known. The use of commercially available closure devices is recommended to assist in arterial closure and to reduce the time of immobility. If a device is not used, manual pressure at the access site on the artery, not the skin puncture site, is held at 15 to 30 minutes, and longer if necessary. This pressure is followed by limited mobility for 6 to 8 hours. Sandbags or other compression devices have been used; however, they can become dislodged easily and fail to apply pressure directly over the site of arterial puncture and allow for continued hemorrhage. These devices obscure the access site, impede visual inspection, and provide a false sense of security; therefore their use is not recommended.

Pseudoaneurysm

Pseudoaneurysms result from failure of the closure in the arterial puncture site, leading to contained bleeding in the soft tissue adjacent to the site of vascular entry. The wall of a pseudoaneurysm is composed of organized thrombus and adjacent soft tissue rather than the vessel wall, as in true aneurysms. Pseudoaneurysms are most commonly seen in the femoral artery (incidence is 0.05% to 0.4%), likely because it is the site most frequently used for access.^8,9 However, it can be seen in any arterial entry including brachial,^9,10 axillary, radial, and popliteal arteries (as high as 2.9%).¹¹

Predisposing factors to pseudoaneurysm formation include anticoagulation, antiplatelet agents, hypertension, and the location of vascular entry.⁸ There is a higher rate of pseudoaneurysm formation if the arterial access is below the femoral head in either the superficial femoral or profunda femoris artery, or at the femoral bifurcation.^4,10,12,13 Difficulty in compressing these arteries and the greater ratio of sheath size to artery diameter may be contributing factors.

Pseudoaneurysms typically develop within 24-48 hours after the intervention, but may not be apparent until several days later. They are associated with pain, and ecchymosis may be present. Similar to a hematoma, pressure created from the mass effect can cause irreversible nerve injury, necrosis of overlying skin, and compression of the veins.⁹ Rarely, pseudoaneurysms can rupture and cause life-threatening hemorrhage.

At the access site, diagnosis is suggested by the presence of a pulsatile mass that is tender to palpation and has a bruit. Diagnosis is confirmed by duplex ultrasound with visualization of the cavity, neck, and bidirectional flow. The examination should note the size and the character of the neck of the pseudoaneurysm. The neck may be wide or long and narrow. Some pseudoaneurysms are complex with multiple lobes.

There are many treatment options, and management of pseudoaneurysms should be based on size and the presence of complications mentioned previously, such as nerve compression. Many small pseudoaneurysms thrombose spontaneously⁸ and may be observed without therapy. Thrombosis usually occurs within 2 to 4 weeks, but possibly later if there is concurrent anticoagulation or antiplatelet therapy. Repeated ultrasound examination for confirmation of closure is recommended.

Surgical repair has been the mainstay of therapy for larger pseudoaneurysms, but it is now seldom used. When needed for enlarging aneurysms or complications, the hematoma is evacuated and the artery is dissected and exposed. The puncture site is then oversewn with suture. It is important not to misidentify a hole in the fascia as the arterial defect. Suture placement in the fascia will lead to recurrent pseudoaneurysm or persistent bleeding.

There are less invasive approaches that are available. Ultrasound-directed compression was first described in the 1990s and uses ultrasound to identify the neck of the pseudoaneurysm. The neck is seen as a high-velocity jet, and direct compression is applied with the transducer. This is associated with significant pain, and is labor intensive. Ultrasound-guided thrombin injection has become the treatment of choice.^9,10 It is preferred over direct ultrasound compression because it produces less patient discomfort and has a higher success rate. Studies have shown it to be successful in 94% of patients, despite 30% of patients being anticoagulated and receiving antiplatelet therapy.⁹ The procedure is performed with ultrasound guidance, with the introduction of needle into the cavity as far away from the neck as possible; 500 to 1000 units of bovine thrombin is injected, and ultrasound imaging is used to see clotting and cessation of blood flow into the pseudoaneurysm cavity. Long, narrow necks are ideal, whereas wide necks are contraindicated. Wide necks with direction communication between the pseudoaneurysm and the artery have higher risks of clot embolization and thrombin injection into the artery.

Arteriovenous Fistula

Arteriovenous fistula is a postprocedural direct communication between access artery and vein, caused by inadvertent puncture of the artery and vein. This complication can occur at any vessel access site. Because most access is obtained at the groin, arteriovenous fistulas are most commonly seen between the femoral artery and vein. A prospective study of patients undergoing coronary angioplasty using duplex ultrasound found an incidence of 2.8%.⁸ In contrast, an incidence of 0.3% was detected when using audible bruit as an indication for duplex study, likely an underestimation of the true incidence.¹⁴ Predisposing factors include periprocedural anticoagulation, hypertension, female gender, left femoral puncture, and popliteal artery access. The increased incidence associated with left femoral access may be due to alteration of the entry angle while standing on the right side. In popliteal artery puncture, the vein is posterior to the artery and this overlap makes the occurrence of fistula more likely.

Most patients with arteriovenous fistula are asymptomatic. Small fistulae may appear with only a thrill or continuous bruit on auscultation. Larger fistulae may have vessel enlargement, leading to aneurysmal dilatation with time. Steal syndrome can develop with flow from the involved artery into the adjacent vein, leading to limb ischemia. A physiologic shunt can be produced, significant enough to elevate right sided filling pressures leading to exacerbation of congestive heart failure in at risk patients.

Once an arteriovenous fistula is suggested by the identification of a thrill or bruit, the diagnosis is confirmed with duplex ultrasound. The examination shows the characteristic systolic-diastolic flow pattern with arterialization of the venous signal.

Many arteriovenous fistulae close spontaneously and may be observed without specific treatment.¹⁵ Symptomatic fistulae should be treated. Surgical repaired is performed by dissecting the artery and exposing the defect. Arterial control is obtained either by clamping or digital pressure. Venous control is obtained by direct pressure. The arterial defect is repaired first, using horizontal mattress Prolene sutures. Usually, only one or two interrupted sutures are needed for the repair.

Less invasive approaches have been described. Successful use of ultrasound-guided compression has been attempted.⁴ Recently there have been several studies describing the use of endovascular repair with stent grafts.^16,17 Arteriography of the groin shows rapid filling of the venous system. A short, covered stent is used to cover the arteriovenous communication.

Retroperitoneal Hematoma

Retroperitoneal hematoma is perhaps the most feared complication of groin access following femoral arterial puncture. It is rare with an incidence of 0.15%, but can be fatal.¹⁸ Following puncture, the blood tracks into the retroperitoneal cavity, and it may not be visible or palpable at the groin. An iliopsoas hematoma can form if the bleeding is contained in the iliopsoas muscle. If there is bleeding into the retroperitoneum, a large amount of blood can accumulate in this large potential space, leading to compression of the ipsilateral kidney and life-threatening complications associated with the hemodynamic derangement of significant blood loss.

Predisposing factors for significant retroperitoneal hematoma formation include periprocedural anticoagulation, double arterial wall puncture, and arterial entry above the inguinal ligament.^18,19 With through-and-through arterial wall puncture, there may be bleeding into the retroperitoneal space from the arteriotomy on the posterior wall. In arterial access above the inguinal ligament, hemostasis is difficult because compression is not against the femoral head.

Symptoms of retroperitoneal hematoma commonly include lower abdominal and back pain. There is usually no ecchymosis initially, but the pain is more severe than the typical periprocedural pain. As the hematoma enlarges, compression of the lumbar plexus in the psoas muscle can cause thigh pain, numbness, or weakness in the quadriceps. The pressure created from the mass effect can also cause venus obstruction with or without thrombosis²⁰ or result in the urge to urinate or defecate. Finally, patients with severe blood loss may have life-threatening hypotension and shock. Conversely, patients may also exhibit normal hemodynamics and few external physical findings.

It is important to maintain a high index of suspicion in patients with lower abdominal, back, and flank pain after groin punctures. Patients with symptoms and any of the physical findings described previously should prompt a computed tomographic scan of the abdomen and pelvis. Initial managements of the retroperitoneal hematoma include stopping and reversing anticoagulation and antiplatelet therapy. Patients need to be stabilized with fluids and blood as needed. Most retroperitoneal bleeds are self limited. Indications for surgery include urgent decompression of the hematoma for patients with compression neuropathy and surgical repair of the arterial defect for persistent bleeding and hematoma progression.

Access Site Occlusion

Occlusion of the artery at the access site can result from thrombosis, dissection, and vasospasm. Predisposing factors include peripheral vascular disease, advanced age, female gender, atherosclerosis, prolonged occlusion by manual pressure or compression device, poor distal runoff, and a hypercoagulable state. Atherosclerosis results in luminal area reduction and increases the risk for plaque disruption, facilitating vessel thrombosis.

Patients with acute occlusion at the arterial access site exhibit signs and symptoms typical of acute limb ischemia. The presence of pulses at the groin may come from the distal external iliac artery, even though the common femoral artery is occluded. Occlusion of the radial artery may be asymptomatic because of adequate flow to the palm supplied by the ulnar artery.

Acute limb ischemia requires immediate intervention with heparinization and thrombectomy. Arteriography can be used for confirmation of the diagnosis and identification of the site of obstruction. Endovascular intervention is not typically used for these complications. Open surgical exploration with thrombectomy, arterial repair, and confirmation of successful restoration of distal perfusion is the treatment of choice.

Groin Infection

Soft tissue infections at the vascular access site after catheterization are rare, but can be potentially severe. They are most commonly caused by gram-positive organisms from the skin flora, especially the Staphylococcus species.^21,22 Predisposing factors include hematoma at the access site, immunodeficiency, obesity, diabetes, and use of closure devices.^23–25 The foreign materials used by these devices can serve as a nidus for infection and cause more access site infections compared with direct compression.²⁶

Patients with access site infections exhibit erythema, induration, and tenderness. There may be purulent drainage associated with an abscess formation or fever and chills from bacteremia. Infections from cellulitis that are mild and superficial respond to antibiotics. More extensive infections may require surgical drainage and debridement in addition to antibiotics. The foreign material from closure devices may need to be removed with repair of any arterial defects.

Several factors may assist in the prevention of soft tissue infection. Percutaneous access should be avoided in areas of soft tissue infection. Repeat access following other recent endovascular intervention should be via a different site if possible. Closure devices should be used only in areas of sterility. Sheaths and catheters should be removed as soon as possible.

Guidewires

Selection

As one gains experience with catheter-based therapy, the number of guidewires and catheters needed to complete an intervention successfully may become fewer. The recommendations in this chapter should serve as a reference for the reader, but are by no means comprehensive (Table 17-2). For initial entry into the artery, a J-tip wire is recommended; it is associated with the lowest risk of dissection. J-tip wires come in a wide variety; some have a movable core that can convert the distal end of the wire from a flexible state to a rigid one. For initial introduction, a nonhydrophilic guidewire with medium rigidity should be chosen. The Bentson wire has a floppy tip, is of medium to firm rigidity and, although straight in its packaged state, forms a large, functional J-tip when being advanced through an artery or vein.

TABLE 17-2 Types of Guidewires and Catheters

Glidewires (Terumo, Tokyo, Japan) can be either straight or angled and are hydrophilic. Angled Glidewires are steerable and can be manipulated with torque at the skin level, with or without an external torquing device. The use of straight Glidewires is not recommended during initial access because they are associated with the greatest chance of dissection. If dissection is suspected but not confirmed, a few simple tests can be performed. If a J-tip wire is used, one can attempt to spin the wire under fluoroscopy. The curved J-tip will not move freely in a subintimal plane. One can also perform hand-held contrast agent injection.

Smaller-diameter wires include 0.018- and 0.014-inch wires. These may be useful in renal, carotid, or infrageniculate manipulations. Use of these wires requires use of appropriately sized catheters, balloon angioplasty catheters, and stents. This may necessitate an expanded inventory and some redundancy, however (e.g., 4-mm balloon angioplasty catheters with a 0.018-inch system and different 4-mm balloon catheters with a 0.035-inch system). Small wires are preferable in many instances when the introduction of the lowest-profile balloon catheter is needed. Recent advances in the design of 0.014-inch wires have made their bodies more rigid, allowing for improved trackability. The 0.014-inch system is currently the preferred system for angioplasty and stenting of renal arteries.

Infusion wires have been designed for use during thrombolytic infusion therapy. These wires have a proximal infusion port and a lumen that allows infusion through the distal aspect of the wire. Typically these wires are passed through a multiside hole infusion catheter, such as a Mewissen Infusion Catheter (Boston Scientific, Quincy, Mass.). Using a coaxial system and a Tuohy-Borst adapter (Cook, Bloomington, Ind.), thrombolytic agents can be infused directly into the clot through the infusion catheter while simultaneously infusing either additional thrombolytic agent or heparin into the distal circulation via the infusion wire.

Catheters

Design

Catheters are made from polyurethane, polyethylene, polypropylene, Teflon, or nylon, with polyurethane catheters having the highest coefficient of friction and Teflon having the lowest. Catheters are sized according to their outer diameter (in French) and their length (in centimeters). Although catheters that have smaller internal diameters are available, most catheters used in angiography will accommodate a 0.035-inch guidewire. The 5-French catheter is most common, but 4- and 6-French catheters are used occasionally. These are matched with appropriately sized sheaths. The most commonly used catheter lengths are 65 and 100 cm.

Functionally, catheters can be either selective or nonselective. Nonselective or flush catheters, which have multiple side and end holes that allow a large cloud of contrast agent to be infused over a short period, are used for large-vessel opacification and in high-flow systems (Figure 17-11). These nonselective catheters can be straight or have shaped ends (e.g., Tennis Racquet or pigtail catheters). There are numerous, interchangeable variations of the curled pigtail shape, with subtle modifications of the tightness of the curls.

FIGURE 17-11 A variety of nonselective flush catheters.

(From Moore WS, Ahn SS, editors: Endovascular surgery, ed 4, Philadelphia, 2011, Saunders, p 65.)

Selective catheters have only a single hole at the tip and are used to intubate vascular families (branches off the aorta) before advancement of the wire (Figure 17-12). With angiography that includes selective catheterization, smaller amounts of contrast material are used at lower injection rates to obtain adequate arterial opacification. When using selective catheters, care must be taken to avoid intimal injury or dissection of the artery from either direct catheter tip advancement or the forceful injection of contrast material. In addition, a “jet effect” can occur when forceful injection of contrast material pushes the catheter out of the vessel of interest and back into the aorta. Lengthening the “rise of rate” of injection on the power injector control panel can limit these negative effects.

FIGURE 17-12 A variety of selective shaped catheters.

(From Moore WS, Ahn SS, editors: Endovascular surgery, ed 4, Philadelphia, 2011, Saunders, p 65.)

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