Purpose -To examine the relationship between iatrogenic femoral artery injuries and the anatomical site of arterial entry.

Materials and methods -Vascular ultrasound studies and charts were retrospectively reviewed for 19 patients with groin complications following femoral artery catheterization between September 1994 and November 1995. The arterial entry site was determined in each case. Clinical data, including the weight and anticoagulation status of each patient, was ascertained. Size of catheters and duration of groin compression were also noted when feasible.

Results -Pseudoaneurysms and arteriovenous fistulas were the primary iatrogenic injuries identified. The superficial femoral artery and the profunda femoris artery were found to be the sites of arterial entry primarily resulting in the formation of arteriovenous fistulas. Similarly, the majority of the pseudoaneurysms were formed when the superficial femoral artery or the profunda femoris artery was used as the site of arterial entry, whereas a smaller proportion were the result of femoral artery bifurcation punctures. Approximately one-half of the lesions identified were treated surgically; ultrasound-guided compression and expectant management were employed for the remainder of the lesions.

Conclusion -Use of the femoral crease as a landmark results in a low and aberrant arterial entry site, with attendant morbidity, particularly in heavyset patients with altered hemostasis. This could be avoided by meticulous attention to the arterial entry site using fluoroscopy.

The incidence of post-catheterization pseudoaneurysms, or arteriovenous fistulas involving the femoral artery, has been reported to be 0.02 to 0.2%. ^1,2 In recent years, the incidence has been at the upper end of this range, likely secondary to the large size of catheters used and to periprocedural anticoagulation. ^1-7 These complications lead to significant morbidity, with possible sequelae including pain, infection, compression of adjacent structures, rupture, distal arterial insufficiency, and congestive heart failure due to arteriovenous fistulas. ^1,2,7-10 Diagnosis of these complications are easily accomplished using ultrasound. ^{2,3,5,8,11,12} However, attention should be focused on trying to prevent these complications in the first place. In the study described herein, we attempted to correlate the arterial entry site to the incidence of these complications.

Materials and methods

We retrospectively reviewed vascular ultrasound studies and clinical charts in 19 patients with groin complications following femoral artery catheterization between September 1994 and November 1995. The arterial entry site was determined based on the vascular ultrasound study in each case. Clinical data, including weight and anticoagulation status, were obtained from the patient's charts.

Periprocedural anticoagulation was used in all patients. Of the cases reviewed, either a 5-F or 7-F catheter was introduced into the femoral artery. At our institution, we routinely compress the groin proximal to the cutaneous puncture site to ensure adequate control of the femoral artery, accounting for discrepancies between the skin entry and the actual arteriotomy site. Duration of groin compression is typically 20 minutes following femoral artery catheterization; however, documentation of the precise length of time of groin compression for each case is unavailable.

Results

FIGURE 1. An ultrasound demonstrates a fistulous communication between the superficial femoral artery [SFA] and the superficial femoral vein [SFV].

FIGURE 2. (A) An ultrasound demonstrates a fistulous communication between the profunda femoris artery [PFA] and the superficial femoral vein. (B) An arteriogram shows a similar arteriovenous fistula between the profunda femoris artery and the superficial femoral vein.

FIGURE 3. This ultrasound demonstrates a pseudoaneurysm arising from the superficial femoral artery.

FIGURE 4. This ultrasound image demonstrates a bilobed pseudoaneurysm arising from the profunda femoris artery.

A retrospective review of 19 groin complications following femoral artery catheterization at our institution revealed 10 arteriovenous fistulas and 11 pseudoaneurysms. The arterial entry site was aberrant in all arteriovenous fistulas and 82% of the pseudoaneurysms, as determined by ultrasound and color-flow Doppler analysis (figures 1,2A,3,4) and angiography (figure 2B). The average weight of the patients was 183 pounds (range 141-297 pounds). Sixteen of the 21 lesions identified required either surgical intervention or ultrasound compression.

Discussion

According to classic anatomic description, the common femoral vein is medial to the common femoral artery at the level of the inguinal ligament, but it assumes a more lateral position as they course distally (figure 5). ¹ Another report, based on CT evaluations, suggests that the common femoral artery partially overlaps its accompanying vein in 65% of the individuals studied, and veins accompanying the deep femoral artery tend to lie anterior to it (figure 6). ^1,13 Distal puncture is likely to pierce both artery and vein as they align themselves in the anterior/posterior position. ^1,13 In addition, a distal puncture does prevent adequate vascular compression at the end of the procedure due to the lack of a firm structure deep to the point where pressure is applied. ^1,13

FIGURE 5. This diagram illustrates the anatomic relationship between the femoral artery and vein as they course below the inguinal ligament.

FIGURE 6. An ultrasound image demonstrates the superficial femoral vein positioned between the superficial femoral artery and the profunda femoris artery.

Some angiographers and cardiologists who perform invasive procedures use the femoral crease as a landmark for common femoral artery puncture (figures 7,8). ¹ A study by Lechner at al ¹⁴ demonstrated that the bifurcation of the femoral artery lies below inguinal crease in 20%, at the level of the inguinal crease in 3.5%, and above the inguinal crease in 76.5% of patients. ¹ Additionally, the inguinal crease is an unreliable landmark, as the position of the crease, relative to the underlying vessels, is highly dependent on body habitus (figure 9). ¹

FIGURE 7. This diagram illustrates the anatomic relationships of the femoral head, inguinal ligament, and femoral crease.

FIGURE 8. This image demonstrates the use of fluoroscopic guidance to identify the femoral head for groin puncture.

FIGURE 9. This fluoroscopic image demonstrates how using the femoral crease as a landmark for common femoral artery puncture can erroneously determine the level of the femoral head.

We have found that the use of the inguinal crease in heavyset patients was more likely to result in groin complications than in smaller patients for two reasons. The first is that the inguinal crease (and the panniculus) in larger patients was lower in relation to the femoral head than in thinner patients, and hence resulted in more aberrant arterial entry sites. The second reason for higher rates of groin complications following femoral artery catheterization in obese patients is that groin compression is technically easier in smaller patients, as femoral arterial pulsations are more easily palpated in thinner patients, and adequate compression can be achieved.

The relatively high incidence of arteriovenous fistulae following coronary angiography has been reported in the past. ^2,8,10 This may be related to the simultaneous arterial and venous punctures in some patients and to utilization of large caliber catheters and anticoagulation in these patients. ^1-7 However, we believe significant contributory factors also include the distal location chosen for arterial entry resulting from the use of the femoral crease as a landmark for the location of the common femoral artery. All patients with arteriovenous fistulae in our study had aberrantly low arterial entry sites.

Similarly, a perivascular hematoma, formed when a femoral puncture site which appears to communicate with the arterial lumen via a neck or track fails to heal, has been labeled a pseudoaneurysm. ⁸ It stands to reason that because healing of a femoral puncture site is dependent upon adequate compression, ⁵ a low arterial entry site compromises this. ^1,13 Again, our study corroborates that contention. Of the 11 pseudoaneurysms found, the arterial entry site was at or below the level of the femoral bifurcation in nine patients. The use of anticoagulation and larger caliber catheters compounds the problem and definitely contributes to the incidence of these complications. In addition, compression is more difficult in obese patients.

The femoral crease is an unreliable landmark to identify the position of the common femoral artery. ¹ Ideally, for all angiographic and interventional procedures, we recommend the distal common femoral artery overlying the femoral head as the arterial entry site because the relatively consis tent relationship between the femoral artery and the lower aspect of the femoral head has been well documented. Meticulous attention to the arterial entry site by fluoroscopic means prior to establishing arterial entry will contribute significantly in decreasing these complications. ¹      AR