Pseudoaneurysms of the femoral artery

Pseudoaneurysms of the femoral artery: recommendation for a method of repair

N.K. SHARMA, K.F. CHIN and V.K. MODGILL
Department of General Surgery, Royal Halifax Infirmary, UK

Introduction

Purpose: Formation of an anastomotic aneurysm in the femoral artery is one of the major complications after femoral artery surgery. The aim of this study was to assess the method of repair of femoral anastomotic aneurysms and their outcome in a District General Hospital. Methods: A retrospective consecutive cohort of anastomotic femoral aneurysms, operated between 1977 and 1998, were studied. Results: Twelve patients with a total of 19 pseudoaneurysms were treated. Five of the aneurysms were repaired using a vein patch and two had re-suturing of the anastomosis. Twelve aneurysms were repaired with complete revision of the anastomoses using interposition grafts. There were no recurrences in the interposition graft group whilst two recurred in the seven aneurysms repaired using re-suturing / vein patch. Conclusion: Interposition grafting would appear to be the method of choice for repair of femoral pseudoaneurysms as the outcome was better than that with re-suturing
or using a patch closure technique.

Keywords: Femoral artery, interposition graft, pseudoaneurysm

J.R.Coll.Surg.Edinb., 46, August 2001, 195-197

INTRODUCTION

Formation of a pseudoaneurysm at an anastomotic site is one of the major complications of arterial surgery. The commonest site for a false aneurysm to develop is at the femoral artery anastomosis in the groin. ^1,3,6 Such an aneurysm has a connective tissue wall and a pseudocapsule. It communicates with the lumen of the native artery through a defect in the anastomosis. Numerous factors have been noted to result in this defect. ^1,2,5,6,7 In the absence of infection, these anastomoses may be repaired by re-suture of the anastomosis with or without a patch or by graft replacement (interposition graft). This retrospective review of patients with false aneurysms treated at our institute was undertaken to assess the method of repair and the outcome.

This is a retrospective study in which a sequential cohort of cases of pseudoaneurysms of the femoral artery operated upon at the Royal Halifax Infirmary, between 1977 and 1990, were identified from theatre records. Follow up information and additional data were obtained from the medical records of individual patients. The data included the epidemiological characteristics of each patient, method of presentation, history of previous vascular surgery, treatment received each occasion, the outcome of each operation and follow-up information.

Type of graft		Number of patients
Dacron grafts	Aortobifemoral	10
PTFE grafts*	Axillobifemora	1
	Femoropopliteal	1

Twelve patients with 19 femoral pseudoaneurysms were treated. There were nine men and four women with a mean age of 67 years. Most of aneurysms occurred following aorto -bifemoral dacron grafting (Table 1). Five patients presented with bilateral aneurysms with two of these patients developing recurrent pseudoaneurysms following repair. The remaining seven patients had unilateral aneurysms. The mean time from graft insertion to aneurysm formation was 100 months (range, 0.5-216 months). This was slightly longer at 111 months when dacron had been used to create the bypass. The two recurrent aneurysms developed, on average, 42 months after initial repair.

Eight of the pseudoaneurysms presented with an asymptomatic groin swelling. The remaining 11 pseudo -aneurysms presented with symptoms of either pain, increase in size or with rupture. Three of these were noted to have an asymptomatic aneurysm on the contralateral side and these are included in the eight asymptomatic pseudoaneurysms.

Pre-operative ultrasound imaging was undertaken in only five of the 12 patients. There were 17 primary and two recurrent pseudoaneurysms. Five of the 17 primary pseudoaneurysms were bilateral, three occurring metachronously and two synchronously.

Patients were categorised into three groups according to the type of repair performed. Five of the aneurysms were repaired using a vein patch and two had re-suturing of the anastomosis. In these two groups, the defect in the anastomosis was repaired with re-suture or patch application without complete revision of the anastomosis. Twelve aneurysms were repaired by excision of a segment of the graft and anastomosis, trimming of the arteriotomy and replacement with additional graft material (Dacron‘ or polytetra-fluoro-ethylene [PTFE]). This was designated the inter-position repair. Failure of repair was the development of a recurrent aneurysm requiring further surgery; this occurred in two patients. There were no deaths or limb losses due to surgical intervention. Of the seven aneurysms repaired using re-suture/vein patch, two recurred giving a recurrence rate of 28.6%. There were no recurrences in the interposition group.

DISCUSSION

Formation of a pseudoaneurysm following major arterial surgery is a serious problem. It poses a substantial risk to both limb and life. Mortality rates of up to 20% and limb loss of 27% have been reported. ¹⁰ There was no mortality or limb loss in our small series.

The age and sex distribution was similar to other series. The clinical presentation of femoral pseudoaneurysms with a pulsatile mass in 61% of the patients in our series is in agreement with other published studies. Patients may also present with pain or complications such as rupture, occlusion and embolism. Complications are reported to occur, prior to presentation, in up to 20% of cases of false aneurysms. ¹⁰ Incidence of rupture has been reported to occur in up to 50% of patients.

In our series, the time from graft insertion to aneurysm presentation varied from 2 weeks to 18 years with an average of 8 years. This is comparable to other reported series. In addition, 29.4% of patients with primary pseudoaneurysms had bilateral synchronous or metachronous groin aneurysms.
Similarly, Millili et al (1980) have also reported a high incidence of bilateral aneurysms - 57.9% in their series of 19 patients.³ It would appear, therefore, that some patients do have a propensity to develop bilateral pseudoaneurysms.

Our study found a very low rate of imaging being performed for the femoral pseudoaneurysms. Only 20% of the aneurysms had pre-operative ultrasound imaging of the groin. Current practice includes ultrasound to assess the extent of the aneurysm and angiography, where indicated. Anastomotic failure can be due to a number of different factors with arterial wall failure being the most frequent. ^1,4 Technical factors, such as too small bites of the arterial wall resulting in inadequate suture placement, are another common cause. It is difficult to differentiate between these two causes at the time of operation. It has been shown that in pseudoaneurysms, the arterial wall may have marked degeneration with loss of smooth muscle and elastic lamina fragmentation. This would be consistent with both arterial wall and technique failure.

The mechanism of production of the stresses leading to formation of pseudoaneurysms is unknown. Too large a graft or too long an arteriotomy have been proposed as factors placing greater strain on the anastomosis.^1,2,5 In addition to stress, there is increased turbulence under such circumstances. The recommendation, therefore, is to use a graft limb size close to or slightly less than the host artery. It is accepted that a graft under tension will produce increased stresses at the anastomotic site. We believe that this factor contributed towards formation of pseudoaneurysms in some of our cases, and also for the high failure rate (28%) in our re-suture/vein patch group. Infection, suture failure, hypertension and local endarterectomy are other factors thought to make a contribution.^1,4,5,7 The part played by these factors was not assessed in our series. Mono-filament sutures must never be grasped by the needle holder or haemostats to prevent suture failure.

In our series, the two recurrences occurred following re -suture/patch closure. Of the 13 aneurysms repaired using an interposition graft, none developed a recurrence at 12 months following repair. Interposition grafting as a method for repairing anastomotic femoral aneurysms has also been noted by others to give better results. ^1,7 Our overall recurrence rate of 10% is in agreement with reported rates of 5-10%.⁹

CONCLUSION

The development of an anastomotic aneurysm should be viewed as a total failure of that anastomosis. In this small series of 19 repairs of pseudoaneurysms, it appears that the outcome following replacement with an interposition graft was better than by re-suture or patch closure. However, it should be emphasised that the number of recurrences in this series is too small to be of any statistical significance, and this problem is not amenable to a randomised trial. Nonetheless, the experience that is reported in this series leads us to favour the replacement with an interposition graft as the preferred method of repair for pseudoaneurysms of the femoral artery. Despite the low incidence of femoral pseudoaneurysms in a district general hospital, re-do vascular surgery such as repair of these pseudoaneurysms can be performed safely.

REFERENCES

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Copyright date: 19th February 2001
Correspondence: NK Sharma, Consultant Surgeon, Department of General Surgery, Royal Halifax Infirmary, Free School Lane,
Halifax HX1 2YP, UK

Š2001 The Royal College of Surgeons of Edinburgh, J.R.Coll.Surg.Edinb.

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