Identifying and treating femoral artery pseudoaneurysms following invasive cardiac procedures

MedSurg Nursing, April, 1997 by Joan Kienast, Denise Fitzgerald

Advances in interventional cardiology offer new choices for patients with coronary artery disease. Unfortunately, these new procedures are associated with complications, such as femoral artery pseudoaneurysms. Accurate and timely vascular assessments by adult health nurses can detect this problem and result in prompt treatment, sometimes including ultrasound-guided compression.

Nonsurgical revascularization of the heart became possible in 1977 with the introduction of percutaneous transluminal coronary angioplasty (PTCA) (Balm, 1993). Due to improvements in technology and operator skill, angioplasty success rates approach 95%, with less than 3% of patients needing emergency bypass. About 300,000 PTCA procedures are performed yearly in the United States (Lacy, Box, Connors, Penney, & Wright, 1990). New device angioplasty procedures are allowing interventionalists to approach lesions that in the past would not have been suitable for angioplasty. These procedures include directional coronary atherectomy, rotational coronary atherectomy (rotablator), placement of intracoronary stems, and laser balloon angioplasty.

Vascular complications following PTCA and related procedures include hematoma formation, pseudoaneurysms, arterio-venous(A-V) fistulas, blood loss requiring transfusion, retroperitoneal bleed, and acute ischemia of the lower limb. The incidence of vascular complications after PTCA is 2% to 5% (Moscucci et al., 1994).

The newer procedures require larger arterial sheaths and vigorous anticoagulation, which place these patients at a greater risk for developing vascular complications than those patients undergoing routine PTCA. The purpose of this article is to describe the formation and assessment of a pseudoaneurysm versus an A-V fistula, discuss the nurse's role in recognizing femoral pseudoaneurysms, and to describe a new treatment option called ultrasound-guided compression and the recommended nursing care.

Pseudoaneurysm Formation

Femoral artery pseudoaneurysms following femoral artery puncture has a reported incidence of 0.2% to 0.5% (Moscucci et al., 1994). Since new device angioplasty, there has been a ten-fold increase in incidence (Pompa et al., 1993). A pseudoaneurysm is defined as a false lumen that occurs at an arterial puncture site and contains active flowing arterial blood. A pseudoaneurysm differs from a true aneurysm in that it occurs as a "pouch" attached to an artery, while a true aneurysm is a circumferential thinning or weakness of an arterial wall. Pseudoaneurysms do not have arterial wall linings but are pulsatile hematomas (a collection of blood in the extravascular space) caused by blood flow through a wall defect (see Figure 1).

[Figure 1 ILLUSTRATION OMITTED]

Pseudoaneurysms occur due to penetrating or blunt trauma to an artery. This trauma may be a result of an arterial puncture site, orthopaedic procedures, or failure of anastomoses in arterial reconstruction. Formation of the pseudoaneurysm occurs as arterial blood flows through the open puncture site, collects and forms a pocket within the surrounding tissue (Schwend, Hamsch, Kwan, Bojajian, & Otis, 1993).

Certain factors may contribute to the development of a pseudoaneurysm. These include both predisposing patient factors and operator factors. Predisposing patient factors include vigorous anticoagulation, age greater than 70, female gender, low nadir platelet count, hypertension, atherosclerosis, and aortic insufficiency. Some operator factors may include multiple catheter exchanges, poor hemostasis during the procedure or after catheter removal, or a puncture placed too low (below the common femoral artery, in the superficial or profunda femoral artery) (Lacy et al., 1990; Moscucci et al., 1994; Shapiro, Cohen, Crystal, & Katz, 1992) (see Figure 2).

[Figure 2 ILLUSTRATION OMITTED]

Diagnosing a Pseudoaneurysm

A tentative diagnosis of psuedoaneurysm can be made by clinical examination and is confirmed by noninvasive duplex ultrasonography. On physical exam a pseudoaneurysm will appear as a pulsatile mass noted at the site of puncture or trauma. The pulse will feel broader than an artery on the opposite limb. The patient may complain of localized tenderness at the site, and ecchymosis of surrounding tissue may be evident. On auscultation, a systolic bruit is usually heard.

Pseudoaneurysms vary in size and consistency. They may range from 0.5 cm to 3.0 cm or greater. The psuedoaneurysm may be filled with arterial flow or may consist of arterial flow and thrombus. The pseudoaneurysm size is determined by measuring active flow and thrombus that make up the entire hematoma cavity.

Assessment should include differentiation of a psuedoaneurysm from an A-V fistula (see Table 1). On physical exam, a pseudoaneurysm differs from an A-V fistula in that an A-V fistula does not have a pulsatile hematoma. An A-V fistula is an artificial communicating tract between an artery and a vein. There is not a "pocket" associated with an A-V fistula. On palpation, a "thrill" is present. On auscultation, a "to & fro" bruit is heard during systole and diastole.