The Atherosclerotic Popliteal Artery Aneurysm

Συντάχθηκε από:

Αναστάσιος Λιάτας, MD, F.I.C.A. – Διευθυντής Χειρουργός

A C Liatas, MD, F.I.C.A. – Consultant Surgeon

Athens  General  Hospital  » EVAGELISMOS «

1

2

Introduction

Aneurysms of the peripheral vessels are located in most cases in the popliteal arteries and are mainly atherosclerotic in nature. Popliteal artery aneurysms cause serious complications and they are the 2^nd most common ones after abdominal aortic aneurysms.

In contrast to the aneurysm of the abdominal aorta, with rupture being its main complication, the popliteal artery aneurysm causes primarily an acute or chronic ischemic syndrome. The morbidity of the popliteal artery aneurysm is high because it is mostly diagnosed and treated when complications have been established. Hence, during the first examination, Wychulis and Evans have identified evidence of a previous arterio-arterial embolism in 38% and 51% of their cases respectively and in 12% of the patients’ toes necrosis existed already.

In an effort to minimize morbidity, every attending doctor has to be proficient in both the natural course of the disease and the therapeutic alternatives in both the acute and chronic stage.

In this study, we present an analysis of our own patients with regard to the diagnosis, surgical treatment and interventional results of the acute and chronic course of atherosclerotic popliteal artery aneurysms.

Patients and methods

28 patients with 48 popliteal artery aneurysms were treated as in-patients between 1982 and 1990. We found bilateral popliteal artery aneurysms in 19 (68%) patients whereas in 10 (36%) ones popliteal artery aneurysm coexisted with aneurysm elsewhere in the body. 36 (75%) of the popliteal artery aneurysms developed complications, specifically 15 (31%) developed peripheral arterio-arterial embolism, 16 (33%) had acute arterial thrombosis, 4 (8%) presented with non treatable ischemic damage of the affected extremity, 1 (2%) had ruptured and 2 (4%) had concomitant compression-caused venous thromboses. The severe complication of acute arterial occlusion resulted in amputation in 20% of the cases. Peripheral embolisms had caused obstruction of the outflow tract with persistence of incapacitating intermittent claudication even postoperatively. Severe ischemic complications occurred in cases of small aneurysms as well. In conclusion, all popliteal artery aneurysms regardless of their size must be treated promptly in order to avoid serious complications.

Clinical picture

The characteristic clinical and the diagnostic findings were as follows:

1. In all cases of non-thrombosed aneurysms, there was a striking palpable pulsating mass in the popliteal fossa, whereas in the thrombosed aneurysms there was a palpable non-pulsating mass in the area.
2. In cases of acute ischemia of a lower extremity along with a coexisting aneurysm in the ipsilateral popliteal fossa, the cause of the ischemia was also a popliteal artery aneurysm.
3. Aneurysms on both popliteal fossae were found in 19 (68%) patients. Like Brunner, we do observed significant differences between sides.

Diagnosis

The diagnosis was completed with the x-ray examinations. The simple radiogram showed in some cases the calcified aneurysmal border. Ultrasonography and computer tomography helped in establishing the diagnosis and determine the size of the popliteal aneurysm, in addition to investigate and localize further coexistent aneurysms elsewhere in the body. Furthermore, these examinations were helpful in the differential diagnosis regarding cystic formations or tumors. Unfortunately, these diagnostic modalities do not give sufficient information about the condition of the peripheral vessels distal to the aneurysm, which are however important for the surgical planning. The arteriography was almost in every case typical for the aneurysm, except for the cases with partial or total occlusion.

Surgical Method

In 34 surgeries a medial femoropopliteal access was chosen, while a dorsal one was chosen only in one surgery. The aneurysm (if small) was eliminated through proximal and distal ligation. Collaterals, if present, were ligated as well. Big aneurysms were clamped off at the proximal and distal end, were opened lengthwise and were evacuated from the thrombotic material. In order to avoid popliteal venous injuries, only a partly resection was performed, preserving the wall section adjacent to the vein. The re-establishment of the vascular continuity was effected in 21 cases with an autologous venous transplant of the contralateral great saphenous vein. In the remaining 14 cases, we used synthetic grafts, mostly PTFE. If the trifurcation was involved in the underlying disease or in the case of occlusion of the same, the distal anastomosis was usually performed without any difficulties, due to the general vascular dilation, in the central or distal part of the arteries of the lower leg.

In all cases with acute ischemia, a generous fasciotomy was performed following the completion of vascular continuity.

Discussion

Aneurysms of the popliteal artery are the most frequent ones among all peripheral aneurysms. They are mainly of atherosclerotic in origin and only 4% of the cases have different origin, such as: Marfan syndrome, syphilis, bacterial infection, Behçet-syndrome, trauma or entrapment syndrome of the popliteal artery. The medical condition usually becomes apparent in the 5^th-7^th decade of age and afflicts mainly men in a gender ratio of 30:1.

The most frequent severe complication of popliteal aneurysms is the acute thrombotic occlusion, which often has a dramatic course.

The timely diagnosis and treatment of the acute cases is decisive for the final result. Apart from the acute arterial occlusion, the popliteal aneurysm leads also to peripheral arterioerterial embolisms which can be asymptomatic.

We did not experience any amputation in the “a froid” operated cases, but we observed a persistence of the pre-existing intermittent claudication with invalidating consequences. The frequent permanent invalidity of patients operated upon in the complication stage, calls for timely surgery of all popliteal aneurysms, regardless of their size.

This paper was presented in «Aneurysma, Forum Angiochirurgicum», Innsbruck 4 – 6 October 1990

and has been published in: [ angio archv Bd. 20 (1991); 278-281 ]

The full article is free (.pdf) : Atherosclerotic aneurysm of the popliteal artery