Introduction
The common femoral artery (CFA) is considered the most frequently used percutaneous arterial access site. Multiple methods are used as a landmark for entry, including pulse palpation, fluoroscopic guidance, and ultrasound-guided puncture to achieve arterial access. Many access-related complications can occur, and some are life and limb threatening, such as retroperitoneal hemorrhage or arterial occlusion. Older studies have reported femoral access site complication rates ranging from 2% to 17% in patients undergoing diagnostic and interventional procedures. A more recent study has shown femoral access complications of 1.8% for diagnostic and 4% for interventional procedures. Arterial sheath placement into the CFA, and not the deep or superficial femoral artery (SFA), has been shown to decrease access complications. The purpose of this chapter is to discuss the common complications caused by femoral artery access and their management.
Risk Factors
Vascular access site complications are the most frequent cause of complications during peripheral vascular and coronary interventions. Risk factors for access complications can be divided into physiological (patient related) and anatomical (procedure related). Physiological risk factors include female gender, body mass index, older age, peripheral vascular disease, renal failure, and low platelet count. Anatomical related factors include previous catheterization, high doses of anticoagulation and prolonged anticoagulation, use of thrombolytic agents, use of GP IIb/IIIa inhibitors, larger arterial sheaths, concomitant venous sheaths, prolonged sheath placement, and prolonged procedure duration.
Identifying patients with these risk factors is a crucial step in planning the appropriate access site and technique to decrease the incidence of access complications. Most of these complications are preventable by following a good patient selection process, utilizing a thorough history and physical examination and a good access technique. History of prior interventions, previous groin complications, use of closure devices, prior groin radiation, and use of anticoagulation should be documented prior to the procedure. A thorough physical examination, including inspection of the groin for any signs of infection, scars from previous surgeries, and palpation of the femoral pulse, will minimize surprises on the day of the procedure and will decrease the risk of complications.
Ideal Puncture Site
The CFA is defined as the continuation of the external iliac artery from the level of the inguinal ligament to its bifurcation into the profunda femoris artery and the SFA. It is relatively large, less involved with atherosclerosis, and compressible against the underlying head of the femur. The ideal site of femoral arterial puncture is at the CFA at a point approximately 1 cm lateral to the most medial aspect of the middle of the femoral head ( Fig. 1.1 ). Caudal punctures usually result in more tendencies for sheath insertion below the bifurcation into the SFA or the profunda femoral artery. These vessels don’t have the underlying bony structure, resulting in increased incidents of bleeding, hematoma, and pseudoaneurysm (PSA) formation. The inferior epigastric artery courses toward the inguinal ligament, then turns upwards in a U-shape configuration. The lowest point of the inferior epigastric artery corresponds to the inguinal ligament. Any arterial puncture above the level of the lowest point of inferior epigastric artery is associated with a significant increase in the risk of retroperitoneal hemorrhage.
Despite agreement on the optimal location for artery puncture, there is a large variation in the landmarks utilized to identify the puncture site. The most commonly used landmarks are the inguinal skin crease, maximal pulsation, and bony landmarks. The inguinal skin crease is located 3 cm below the inguinal ligament in 95% of cases and doesn’t correlate with its location. It is the least reliable method and should be avoided. The point of maximum pulse can often be obscured by obesity, prior hematoma, or scarring from previous surgery; this makes it less reliable.
The anatomic relationship of the CFA to the underlying femoral head is relatively constant. Garrett et al. found that the CFA overlies the femoral head in 92% of cases. They also concluded that the femoral head has a consistent relationship to the CFA, and localization using fluoroscopy is a useful landmark. However, there are critical issues that must be considered in the application of this technique, including the impact of parallax. Placing a hemostat on an obese patient to identify the femur head may be misleading, and correction of the parallax is important prior to arterial cannulation ( Fig. 1.2 ).
During the past decade, real-time ultrasound guidance has gained popularity among angiographers. It allows the user to visualize, in real time, the needle as it enters the ideal point in the mid-CFA. The Femoral Arterial Access with Ultrasound Trial (FAUST) randomized patients to fluoroscopic- versus ultrasound-guided puncture. This study showed no significant difference in successful CFA cannulation rates between the fluoroscopic group versus the ultrasound-guided group. However, in the subgroup of patients with a high bifurcation, there was a significant difference in favor of ultrasound. Ultrasound guidance also improved the first-pass success rate, reduced the number of attempts, decreased inadvertent venipuncture, reduced median time to access, and decreased subsequent vascular complications. Visualizing the tip of the needle entering the mid portion of the CFA is a very critical step when using real-time ultrasound guidance. Failure to perform this step adequately can result in a higher puncture rate by “losing sight” of the needle tip that transverses the tissue in a cephalad trajectory.
Most physicians in the authors’ institution prefer a combined approach. First, the femur head is identified by fluoroscopy. Then, real-time ultrasound guidance is used to identify the CFA bifurcation. The tip of the puncturing needle has to be identified in the middle of the CFA prior to advancing the wire and placing the sheath. If the CFA can’t be safely identified using ultrasound guidance, a fluoroscopy-assisted technique using a Doppler needle (SMART needle) is used. The CFA is identified using fluoroscopy and the artery is punctured using the Doppler needle. This allows the operators to identify the CFA waveform, which reduces inadvertent venous and arterial branch punctures.
Groin Hematoma and Pseudoaneurysm
Etiology and Clinical Presentation
Bleeding complications from a femoral artery access and sheath insertion have a wide range of clinical manifestations, ranging from localized hematoma to life-threatening hemorrhage. Failure of the arteriotomy to completely seal or dislodgment of the formed clot results in a hematoma formation. A PSA is a hematoma with evidence of arterial flow on duplex ultrasound. It has a sac and a neck that track to a nonsealed arteriotomy. The term “pseudo” refers to the sac being surrounded by soft tissue, lacking arterial wall. The reported incidence of femoral artery pseudoaneurysms ranges from 0.2% to 2.9%. Multiple patient-related and procedure-related factors have been identified. Patient-specific factors include body mass index, female gender, degree of arterial calcifications, and preprocedural platelet counts. Procedure-specific risk factors include the urgency of the procedure, site of arterial cannulation, size of the sheath, combined arterial and venous access, procedural antiplatelet medication use, and anticoagulation.
PSA is a result of inadequate compression of the blood vessel following sheath removal or failure of a closure device to adequately close the arteriotomy. Identifying the femoral head using fluoroscopy, even when ultrasound is used for access, will decrease the incidence of high or low accesses and prevent inadequate compression. Identifying patients at high risk is crucial in avoiding multiple attempts to obtain access and decreasing the incidence of access complications and PSA formation. Making sure the operating room staff are well trained and capable of performing manual compression will aid in decreasing the overall complication rate. If using closure devices, proper selection and deployment are crucial in decreasing bleeding complications.
The clinical presentation of PSAs is determined by their size. Groin pain, discoloration, and pulsatile mass are manifestations of small PSAs. Larger PSAs can present with compression symptoms, including nerve compression, resulting in neuropathy, compression of adjacent vein causing deep vein thrombosis (DVT), or skin compression causing necrosis. The first step in diagnosing PSA is to perform a thorough physical exam. A pulsatile mass with a systolic bruit is evident on examination, with or without skin manifestations. Limb swelling may also be present. It is caused by an underlying hematoma or PSA compression of the femoral vein that rarely results in DVT. Kent et al. reported that physical examination was extremely accurate, with a sensitivity of 83% and a specificity of 100%.
Diagnosis and Management
Groin Hematoma
Arterial duplex is the study of choice for the diagnosis of patients with a groin complication after CFA access. It is considered the primary study for size monitoring for conservative treatment. It is also used for direct manual compression and thrombin injection, if a nonsurgical approach is considered. Duplex imaging using B-mode identifies hematomas as a hypoechoic mass and measures their size. The color flow imaging is used to assess flow to differentiate a hematoma from a PSA. Color flow will demonstrate the classic “yin–yang” shape as arterial blood leaves the arteriotomy and reflects back into the artery. Doppler waveform analysis should also be performed to rule out the presence of concomitant arteriovenous fistulae, presenting with a low resistance pattern with a diastolic flow component.
Groin hematomas can occur acutely in the angiography suite or in the recovery room immediately after the procedure. These hematomas can be a marker for an underlying catastrophe (retroperitoneal bleed or arterial rupture). Direct manual compression on the access site is the first step in management. The patient’s vitals should be monitored to identify any hemodynamic instability requiring fluid resuscitation and blood products’ administration. All intravenous and oral anticoagulants should be discontinued. Laboratory assessment of coagulation factors, platelets, and hemoglobin should be done every 4–6 hours until corrected. CT angiography may be required if retroperitoneal bleeding or active extravasation is suspected.
Asymptomatic groin hematomas should be observed with serial physical exams to assess their growth or resolution, and a duplex ultrasound should be obtained to rule out PSA formation. Most of these hematomas resolve spontaneously and rarely require surgical intervention. Symptomatic hematomas and patients with hemodynamic instability require open groin exploration and evacuation. The femoral vessels should be inspected and the arteriotomy should be primarily repaired. CFA endarterectomy may be required if the artery is significantly diseased.
Pseudoaneurysm
The management of PSA has evolved during the past decade. Multiple approaches have been used including observation, ultrasound-guided compression, ultrasound-guided thrombin injection, and, rarely, open surgical repair.
Observation
Observation plays an important role in the treatment of iatrogenic PSAs, and it’s reserved for small asymptomatic PSAs (<3 cm in diameter). Multiple studies have reported successful thrombosis of PSAs with conservative management. Kresowik et al. treated seven PSAs conservatively, ranging in size from 1.3 to 3.5 cm. These PSAs were monitored weekly with serial duplex examinations, and all of them spontaneously thrombosed within 4 weeks from the initial diagnosis. Kent et al. reported that one-third of observed femoral pseudoaneurysms required repair. Nine of 16 pseudoaneurysms spontaneously thrombosed, and the size of these PSAs did not correlate to the number of patients who required repair. Three of the seven patients who required repair were taking anticoagulation medications, which led the authors to recommended PSA repair in patients who require anticoagulation.
Toursarkissian et al. have the largest and most quoted study in the literature. They observed 147 patients with PSAs with a maximum diameter <3 cm. The main exclusions for enrollment were the need for immediate surgical intervention or the use of anticoagulants. Intervention was avoided in 89% of patients, with a mean time to thrombosis of 23 days.
Ultrasound-Guided Compression
Fellmeth et al. reported the first minimal invasive treatment for iatrogenic PSAs in the 1990s. They reported a >90% success rate with ultrasound guided compression, encouraging a nonsurgical approach as the first line of management. The procedure is done by placing the ultrasound probe on the groin with direct visualization of the neck of the PSA. Pressure is applied to the probe to eliminate flow through the PSA neck, with maintenance of arterial flow in the femoral artery and continued evaluation at 5- to 10-minute intervals to assess arrest of flow into the PSA sac. Limitations of this technique include patient discomfort, frequent need for sedative administration for patient comfort, and operator fatigue. In a series of 219 PSAs, the highly statistically significant predictors of failure of ultrasound-guided compression were ongoing anticoagulation and length of aneurysm neck (<10 mm), with a success rate of 71% versus >93%, respectively.
Duplex-Guided Thrombin Injection
Cope and Zeit described the initial technique 25 years ago. Duplex-guided thrombin injection (DGTI) has replaced ultrasound-guided compression as the initial therapy of choice, secondary to the speed of thrombosis, reduction in pain associated with the procedure, and improved success in most series. The procedure is performed under the guidance of B-mode imaging by injecting thrombin directly into the PSA sac. Color Doppler mode is used to assess the PSA thrombosis while the thrombin is being injected. The most significant complication of the procedure is thrombosis of the femoral artery or vein as a result of direct injection of thrombin into these vessels. This can be avoided by visualizing the tip of the needle in the PSA sac prior to thrombin injection, and injection of small amounts of thrombin under color flow imaging to avoid spillover into the arterial system. The patency of the femoral vessels has to be confirmed at the end of the procedure, which can be accomplished using color Doppler mode and by performing a pulse exam.
The largest nonrandomized study directly comparing ultrasound-guided compression and DGTI was reported by Khoury et al. One hundred eighty-nine patients were treated using compression and 131 using DGTI; the success rate favored DGTI (96%) over ultrasound-guided compression (75%). The primary reason for compression failure was pain with compression or deep PSAs that did not allow for adequate compression. DGTI failures were primarily related to intraarterial injection of PSAs <2.5 cm and those with short necks. In the authors’ experience of >200 DGTI, we had one patient with acute limb ischemia. This patient presented immediately after the injection procedure with CFA occlusion and underwent successful open surgical thrombectomy.
It appears from the aggregate of retrospective studies that symptomatic and large (>3 cm) PSAs are more effectively treated with DGTI. DGTI should be avoided in asymptomatic patients with a PSA sac <1 cm and PSAs with short necks. These patients should be treated with ultrasound-guided compression or open surgical approach if compression fails.
Retroperitoneal Hemorrhage
Retroperitoneal hemorrhage is a result of a poor access technique that fails to identify the CFA, causing unsafe cannulation and sheath insertion. High punctures, cephalad to the lowest portion of the inferior epigastric artery, increase the risk of developing retroperitoneal hemorrhage. A puncture at this location is difficult to compress because there is no bony structure (i.e., the femoral head). In addition, the retroperitoneum is a large cavity and can accommodate large amounts of blood, which can result in hemodynamic instability in some patients. Retroperitoneal hemorrhage is rare, but can be life-threatening. High suspicion and early diagnosis are keys to decreasing morbidity and mortality.
Clinical Presentation and Diagnosis
This diagnosis is readily made on clinical presentation and manifests as unexplained hypotension or vagal reaction, either during the procedure or immediately after CFA sheath removal. If the patient complains of vague back pain or abdominal pain after a CFA access procedure, this should raise suspicions of retroperitoneal hemorrhage. A large retroperitoneal bleed may compress the femoral nerve, causing neuropathy. The physical exam is usually unremarkable; however, patients may present with abdominal fullness and flank ecchymosis (Grey Turner sign). Computed tomography (CT) is the diagnostic test of choice, and the use of contrast can aid in identifying the source of bleeding and guiding treatment. Patients with active retroperitoneal hemorrhage can present with continuous dropping of hematocrit and hemodynamic instability. These patients should be stabilized prior to obtaining a CT scan.
Management
Retroperitoneal hemorrhage can be managed conservatively in most cases by aggressive fluid resuscitation, correction of coagulopathy, and transfusion of packer red blood cells to maintain hematocrit. The patient should be placed on bed rest and undergo serial abdominal exams. Serial laboratory tests, including hemoglobin, platelets, and serum creatinine, should be obtained every 4–6 hours. Indications for surgical intervention include hemodynamic instability, continuous drop in hematocrit, and intractable pain and neuropathy. Patients with signs of hemodynamic instability, who respond appropriately to fluid resuscitation, should be evaluated by CT angiography to identify the source of bleeding. Hypotensive patients who are unresponsive to fluid resuscitation should undergo emergent surgical intervention. Both open and endovascular approaches have been described to manage patients with retroperitoneal hemorrhage. There are no randomized trials to guide the treatment strategies for retroperitoneal hemorrhage, and the evidence is based on small cohort series or isolated case reports. In the authors’ institution, most physicians prefer an endovascular approach, and open surgery is used only if the bleeding cannot be controlled. A contralateral CFA access is obtained and an angiogram of the iliac and femoral vessels is performed to identify the bleeding source. Hemostasis can be achieved by prolonged balloon inflation at the arteriotomy site or placement of a cover stent. If use of a covered stent is planned, care should be taken not to undersize the graft, as this will lead to continued extravasation. If extravasation from a branch vessel is identified, coil embolization of this vessel can be easily performed. If bleeding can’t be controlled using an endovascular approach, retroperitoneal exploration is performed to identify and control the bleeding source.
Arteriovenous Fistula
Iatrogenic arteriovenous fistula (AVF), a communication between the femoral artery and vein, following CFA access is rare. Low arterial punctures caudal to the bifurcation of the SFA and profunda femoral artery can increase the risk of AVF formations. Most AVFs are asymptomatic and are detected during physical exam by palpating a thrill or listening to a bruit. They are usually found incidentally during duplex evaluation of a groin hematoma after a CFA access. The clinical significance of an AVF may result from hemodynamically relevant left-to-right shunts. Kelm et al. investigated the clinical outcome of iatrogenic femoral AVF, and found that none of their patients developed cardiac volume overload. In their study, shunt volumes were estimated in the range of 160 to 510 mL/min, which is far below the 30% of cardiac output that is required to deteriorate right heart function.
The incidence of postcatheterization AVFs varied from 0.006% to 2.28%. Kent et al. routinely examined patients for a new femoral bruit after cardiac catheterization, followed by a duplex scan. The authors diagnosed six new AVFs in 1838 consecutive patients (0.3%). Kresowik et al. used primary duplex scanning to evaluate patients for an AVF development after CFA access. They diagnosed four new AVFs in only 144 patients, resulting in an incidence of 2.8%. Kelm et al. evaluated a total of 10,271 consecutive patients undergoing cardiac catheterization who were followed prospectively over 3 years and reported a 0.86% incidence of AVFs. The risk factors for developing an AVF after CFA access include arterial hypertension, female gender, use of anticoagulation during the procedure, and low arterial puncture.
Diagnosis and Management
Since it is sensitive and cost effective, duplex ultrasound is the study of choice for the diagnosis of iatrogenic AVFs. A communication between the artery and vein is identified on color flow Doppler with evidence of low resistance, diastolic flow in the CFA, and arterialization of the venous signal. CT and magnetic resonance (MR) imaging play an essential role in the diagnosis of extremity AVFs; however, in most cases conventional angiography is still required for accurate lesion localization and tailoring of the surgical or endovascular treatment.
The natural history of traumatic AVFs is poorly understood and, thus, treatment strategies are controversial. Multiple options have been advocated, including observation, open repair, and an endovascular approach. Most AVFs are asymptomatic, which makes observation a safe treatment option. In fact, multiple studies have shown spontaneous resolution of the majority of iatrogenic femoral AVFs with close observation. The authors reported no adverse outcomes of the remaining fistulae that persisted and concluded that asymptomatic patients can be managed safely by close observation. Patients who are treated with conservative management should be followed with routine physical exams and duplex surveillance. Surgical intervention is indicated for patients who develop symptoms of congestive heart failure or limb swelling; or for fistulae that show an increase in size on duplex surveillance.
Open surgical repair is performed via the standard groin exploration. Proximal and distal control of the artery and the vein is obtained and the fistula tract is identified and ligated. The artery and vein are repaired primarily or with patch angioplasty in rare occasions. In cases with a delayed diagnosis of AVF, significant enlargement of the surrounding venous structures and nerve damage can potentially cause difficulties. Recent improvements in endovascular techniques have created significant and effective alternatives to surgical treatment. Metallic coils and covered stents have been utilized frequently for endovascular treatment of AVFs. Treating AVFs with covered stents is technically easy and has been reported to have high technical success rates and low complication rates in different series. However, there is no accurate data regarding the long-term follow-up results of using covered stents in peripheral arteries.
Thrombosis
Local thrombosis of the CFA is a rare well-known complication after femoral access; however, it is more common in patients with pre-existing CFA atherosclerotic disease and patients with previous groin reconstruction. Placing a large-diameter sheath in a small CFA can result in CFA thrombosis. Technical errors while using closure devices and local dissection during CFA access can also cause CFA thrombosis. The risk factors associated with thrombosis of the access site include peripheral vascular disease, advanced age, hypercoagulable state, small caliber vessels, and female gender.
CFA occlusion results in a sudden onset of lower extremity pain, pallor, and absence of distal pulses. The symptoms may not be sudden, if peripheral vascular disease and collateral flow are present. These patients may present with worsening claudication or a new onset of rest pain days or weeks after intervention. Acute limb ischemia, requiring immediate revascularization, may develop. An open surgical approach with CFA endarterectomy and patch angioplasty is preferred. Thromboembolectomy using a Fogarty catheter should be performed to confirm adequate in-flow and out-flow. An endovascular approach using catheter-directed thrombolysis and mechanical thrombectomy is an alternative to open surgery. Using a small sheath in high-risk patients can reduce CFA thrombosis. Appropriate anticoagulation and adequate heparinized saline flushing of the CFA sheath during the procedure is necessary to help prevent local thrombosis.
Groin Infection
Groin infections after CFA access are extremely rare and have a delayed presentation of 1 to 2 weeks postoperatively. Gram-positive organisms, especially Staphylococcus aureus , are the predominate causes of groin abscesses and endarteritis associated with femoral arterial cannulation. Patients present with local signs of infection, including pain and erythema. Fluctuation and local discharge are present in cases with abscess formation, and fever and rigors indicate systemic involvement.
Duplex ultrasound can diagnose groin abscesses and rule out the involvement of the CFA and the presence of PSAs. CT angiography is another modality to confirm the diagnosis of groin abscesses and evaluate for arterial involvement. A complete blood count and blood cultures should be obtained in all patients to assess the level of involvement. A local infection at the access site without abscess formation responds well to oral antibiotics, while systemic involvement requires hospitalization and intravenous antibiotics. Treatment consists of operative exploration and drainage of the abscess. If the arterial wall is involved, debridement of all necrotic tissue and repair with vein patch angioplasty or interposition vein graft is necessary. In cases with significant tissue loss, coverage with a muscle flap can improve wound healing. Extraanatomic bypass (obturator bypass) should be considered in complex cases where groin reconstruction is not feasible.
References
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