Idiopathic pseudoaneurysm of the popliteal artery
(Portuguese PDF version)

Marcio Miyamotto1, Ricardo César Rocha Moreira2, Fabiano Luiz Erzinger3, Graciliano José França4, Andréia Gineste Pedro da Cunha3

1. Vascular and endovascular surgeon, Serviço de Cirurgia Vascular Prof. Dr. Elias Abrão..
2. M.D. and Ph.D., Universidade Federal do Paraná, Chief of the Serviço de Cirurgia Vascular Prof. Dr. Elias Abrão.
3. Former Resident, Serviço de Cirurgia Vascular Prof. Dr. Elias Abrão.
4. Vascular ultra-sonographer, Clínica Ecodoppler Colorido e Angiobatel.

Correspondence:
Marcio Miyamotto
Rua Padre Anchieta, 1995/2004
CEP 80730-000 - Curitiba, PR, Brazil
Phone: +55 (41) 339.2312/244.8787
E-mail: miyamotto@brturbo.com

Serviço de Cirurgia Vascular Prof. Dr. Elias Abrão (Hospital Nossa Senhora das Graças and Hospital Universitário Cajuru of Pontifícia Universidade Católica do Paraná, in Curitiba, PR, Brazil.

ABSTRACT

Pseudoaneurysm of the popliteal artery is a rare condition. It is usually secondary to local trauma, including iatrogenic trauma caused by orthopedic procedures (e.g. arthroscopy). Dehiscense, exostoses and osteochondroma of the femur can cause this vascular lesion as well. The authors report two cases of spontaneous pseudoaneurysm of the popliteal artery. Comprehensive investigation failed to find the cause of this lesion in the two cases.

Key-words: false aneurysm, popliteal artery, aneurysm.
Palavras-chave: pseudoaneurisma, artéria poplítea, aneurisma.

J Vasc Br 2004;3(2):169-72

Pseudoaneurysms are caused by rupture of the arterial wall, followed by hemorrhage, which is contained by surrounding tissues. In some cases, the periarterial hematoma liquifies, maintaining turbulent flow between the arterial lumen and cystic structure locally formed. The resulting lesion is called a pseudoaneurysm or false aneurysm. The first citation of such entity was made by Galen in 170 A. D.

The artery most frequently affected by pseudoaneurysm is the common femoral artery, which is usually used in diagnostic and therapeutic invasive procedures. Pseudoaneurysms of the popliteal artery (PPA) are rare, and associated with several etiologies, according to the literature. The authors present a report of two cases of PPA, which were regarded as idiopathic, after a comprehensive etiological investigation. Reports of similar cases were not found in medical literature.

CASE REPORTS

Case 1: O.S., a Caucasian, 48 year-old male truck driver presented with painful mass in the distal third of the left thigh. He reported three previous treatments of deep venous thrombosis of the same limb, although he was no longer receiving anticoagulant therapy at the time. He did not have any other medical problems. At physical examination, he had palpable pulses and small varicose veins in lower limbs. In the distal third of the right thigh, there was a firm, non-pulsatile mass, without any bruits, thrills or signs of infection. Doppler ultrasound showed a periarterial multi-layered cystic lesion with hemorrhagic content, as well as signs compatible with popliteal and femoral venous thrombosis. Arteriography of lower limbs was performed showing the presence of bilateral pseudoaneurysms of popliteal arteries measuring 8 cm in diameter on the left side and 4 cm in diameter on the right side (Figure 1). The patient underwent simultaneous correction of both pseudoaneurysms with interposition of segments of reverse saphenous vein. During the surgical procedure, after opening the cyst, several thrombotic layers were shown around the lumen of the vessel. There were no signs of arterial inflammation, despite the significant lesion of the arterial wall.

click hereFigure 1 - Bilateral pseudoaneurysm (arteriography).

Case 2: F.M.O.G., Caucasian, 20-year-old female secretary. The patient was referred to our service with complaints of mild pain and of the spontaneous formation of a mass in the distal third of the left thigh (Figure 2). She did not have any associated conditions and had never undergone any previous surgery. At physical examination, a pulsatile mass was found in the medial aspect of her distal thigh, with a systolic bruit, but absence of thrills on palpation. After clinical diagnosis of popliteal pseudoaneurysm, the patient underwent arteriography, which showed a pseudoaneurysm measuring 3 cm in diameter in the proximal popliteal artery. The surgical treatment consisted of a short popliteal bypass with reverse saphenous vein graft. Upon histological examination, the popliteal artery was normal, with no signs of wall inflammation or friability.

click hereFigure 2 - Pseudoaneurysm in left thigh.

DISCUSSION

Pseudoaneurysm of the popliteal artery may be secondary to several factors, trauma being the predominant cause. During the Korean War, in the 1950's, it amounted to approximately 27% of all pseudoaneurysms. Pseudoaneurysm of the popliteal artery represents approximately 1% of all vascular lesions, with a high rate of limb loss due to thromboembolic complications.2,3 Several mechanisms of trauma are involved. Penetrating traumas due to stab wounds or gunshot wounds, and femoral or tibial fractures or fracture/luxation may cause direct lesion to the vessel. Blunt traumas without fractures rarely lead to pseudoaneurysms, given that only a great mechanical force can cause trauma to the popliteal artery. The popliteal fossa is surrounded by a highly resistant structure of muscles and bones; thus, mild traumas will rarely lead to arterial damage, without damaging surrounding structures. Structural alterations on the arterial wall, such as those caused by collagen or connective tissue diseases and by arteritis secondary to septic embolism in patients with infectious endocarditis can rarely cause popliteal pseudoaneurysm formation. Such diseases invariably lead to structural damage, weaken the arterial wall and make the artery more vulnerable to spontaneous ruptures or ruptures due to mild traumas.1,4,5

Over the last decades, with the improvement of techniques for vascular surgery, the variety of invasive procedures performed on the popliteal artery is increasing, that has lead to a higher prevalence of postoperative pseudoaneurysms.1,6 Similarly, iatrogenic traumas related to orthopedic procedures are becoming more common each day. Arthroscopy performed for diagnostic and therapeutic purposes is a possible cause of pseudoaneurysms.7

Bone deformities, such as exostoses and osteochondromas of the tibia and femur, may cause popliteal artery lesions due to its continuous pulsation against irregular bony surfaces. Pseudoaneurysm of the popliteal artery may be an initial presentation of such conditions, which are asymptomatic in most cases.8-10

In the comprehensive etiological investigation of the cases we reported in the present article, a history of blunt or penetrating trauma was exhaustively investigated, though we could not find any evidence in either case. Neither patient had previously undergone orthopedic or invasive arterial procedures that could explain the formation of pseudoaneurysms. Imaging studies (arteriographies, and radiological and ultrasound exams) also did not reveal any anatomical alterations which could suggest other possible causes. Anatomic and pathological studies did not show any histological alteration on the structure of the arterial wall that could explain possible ruptures related to small traumas. There was no evidence of inflammatory processes in the artery or presence of giant cells. Both cases were assessed by rheumatologists in order to rule out any collagen or connective tissue diseases as well as other types of vasculitis. Blood sedimentation rate tests were normal, as well as bleeding time tests and blood tests (erythrocyte, leukocyte and platelet counts). Presence of LE (lupus erythematosus) cells, rheumatoid factor, ANF antinuclear factor, ANCA (antineutrophil cytoplasmic antibodies) and hepatitis B were all negative.

After an exhaustive investigation for the likely cause of pseudoaneurysm of the popliteal artery, which failed to find any evidence, the authors conclude that the two cases reported above are idiopathic pseudoaneurysms of the popliteal artery. Reports of similar cases were not found in the medical literature .

REFERENCES

1. Clark ET, Gewertz BL. Pseudoaneurysms. In: Rutherford RB, editor. Vascular Surgery. Philadelphia: W. B. Sauders Co.; 1995. p. 1153-1162.

2. Davidovic L, Lotina S, Kostic D, et al. Popliteal artery war injuries. Cardiovasc Surg 1997;5(1):37-41.

3. Harrington I, Campbell V, Valazques R, Williams T. Pseudoaneurysm of the popliteal artery as a complication of an osteochondroma. A review of the literature and a case report. Clin Orthop 1991;270:283-7.

4. Melton SM, Croce MA, Patton JH, et al. Popliteal arterial trauma. Systemic Anticoagulation and intraoperative thrombosis improves limb salvage. Ann Surg 1997;255(5):518-29.

5. Marcove RC, Lindeque BG, Silane MF. Pseudoaneurysm of the popliteal artery with an unusual arteriographic presentation. A case report. Clin Orthop 1988;234:142-4.

6. Votapka T, Backer C, Mavroudis C. Giant popliteal false aneurysm in a 8-year-old-child. J Pediatr Surg 1993;28(12):1594-6.

7. Lizama VA, Zerbini MA, Gagliardi RA, et al. Popliteal vein thrombosis and popliteal artery pseudoaneurysm complicating osteochondroma of the femur. AJR 1987;148:783-4.

8. Gillespie DD, Cantelmo NL. Traumatic popliteal artery pseudoaneurysm: case report and review of the literature. J Trauma 1991;31(3):412-15.

9. Lantsberg L, Khodadadi J, Golcman L, et al. Unusual pseudoaneurysm of Dacron femoro-popliteal graft shaft. A case report. J Cardiovasc Surg 1988;29:320-1.

10. Ritt MJPF, TeSlaa RL, Koning J, et al. Popliteal pseudoaneurysm after arthroscopic meniscectomy. A report of two cases. Clin Orthop 1993;295:198-200.

J Vasc Br - Official Publication of the Brazilian Society of Angiology and Vascular Surgery