Bombay Hospital Journal Issue SpecialContentsHomeArchivesSearchBooksFeedback

INFRA INGUINAL BYPASS PROCEDURE FOR ISCHAEMIA IN THE LOWER LIMB

NK BHAGAVAN*, VIVEKANAND***, ML RAGHUNANDAN+, V SRIKANTH**,VENKATESH REDDY++
*Consultant Vascular Surgeon; **Registrar; Manipal Hospital, Bangalore. ***Associate Consultant in Vascular Surgery; +Registrar, Department of Surgery; Yellamma Dasappa Hospital, Bangalore.

PURPOSE : In advanced lower limb ischaemia infra inguinal bypass procedure is the treatment of choice for limb salvage provided there is good distal run off.

METHODS : For this, we reviewed our 10 years’ experience with infra inguinal bypass procedures using both PTFE (Goretex®)graft and autologous saphenous vein.

RESULTS : All results regarding patency and limb salvage were calculated and are presented by graphs 1 and 2. The time period is from 1990-2000. The total number of cases done was 650 cases. Femoropopliteal bypass graft using PTFE (Goretex®) is about 70% and that of infra popliteal bypass graft using autologous saphenous vein is about 40%.

The main negative predictive factor for early occlusion is poor distal run off. Primary bypass procedure had markedly better success rate rather than repeat procedure with primary patency rate of 90% at one year for femoro popliteal bypass and 70% at one year for infra popliteal bypass procedures. The five year cumulative limb salvage rate is about 70% for all infra inguinal bypass procedures and 90% at one year.

CONCLUSION

Although the five year patency of infra inguinal bypass procedure is less than 70%, the high limb salvage in these patients at one year justifies an aggressive infra inguinal bypass procedure in ischaemic lower limb.

Limb threatening ischaemia is often a result of long femoro popliteal vascular occlusion. Although favourable results are reported for above knee infra inguinal bypass procedures when compared to infra popliteal bypass procedures, the prognosis is poor when there is severe rest pain - distal gangrene and also when the distal run off is not good. Using PTFE(Goretex®) graft failure compared to autologous saphenous vein. In 1978 Veith et al first described the use of PTFE(Goretex®) prosthesis for infra popliteal reconstructions. In 1986, in a well designed prospective randomized study the results of autologous vein used as infra inguinal bypass grafts were compared with those of PTFE(Goretex®) prosthesis. There was no significant difference in patency in above knee grafts compared to below knee grafts.


INTRODUCTION


From 1990 through 2000, a total of 650 infra inguinal bypass procedures were performed at our institutions. For all above knee bypass procedures we always used PTFE (Goretex®) grafts and for below knee bypass procedure, we always used reversed autologous saphenous vein graft. We rarely did secondary exploration or repeat bypass procedure on the same patient. When the long saphenous vein was not available, we did use on a few occasions PTFE grafts for infra popliteal bypass procedures.

It is the purpose of this report to review our experience

1.With limb salvage in femoro popliteal bypass procedure using PTFE graft for above knee reconstruction.

2.With limb salvage in femoro distal bypass using autologous saphenous vein for below knee reconstruction and also to study the patency rates for different infra inguinal bypass procedures.

MATERIAL AND METHODS

From 1990 to 2000 a total number of 650 infra inguinal bypass procedures were carried out for limb salvage in severe lower limb ischaemia. We did 250 cases of above popliteal bypass procedures using PTFE (Goretex®) grafts (Fig. 1). We also did 398 cases of below knee femoro distal bypass procedures using reversed autologous saphenous vein and two cases of femoro distal bypass procedures using tapered PTFE (Goretex®) grafts (total 400 cases). The mean age of the patients was 55 years (range 30-80 years). The male : female ration was 3 : 1. At the time of operation 50% had history of smoking, 80% had history of diabetes, 30% had history of ischaemic heart disease and 1% had previous history of cerebro vascular accident.

Fig 1
Fig 1 : Femoropopliteal bypass graft using goretex graft


Indications for infra inguinal bypass procedures were intermittent claudication (short distance) 20% and gangrene and rest pain 80%. None of the acute ischaemic cases were included in this study. During this study two posterior tibial bypass procedures using PTFE tapered prosthetic grafts were done. Both occluded immediately after the surgery.

All patients underwent preoperative arteriography including digital subtraction angiogram. About 10% of our patients also underwent pre-operative duplex scanning when the arteriograms were unable to clearly define the distal runoff and also because of economic factors when the patients could not afford the angiogram. Both angiography and duplex scanning were used to assess the distal vessel runoff status. Most of the patients in this study had long standing occlusion of the femoral artery in the thigh as well as in the popliteal region. When we were unable to show any distal run off either on angiography or by duplex scanning, we did explore the distal vessels (less than 1%) and pass vascular dilators. If the vascular dilator went for about 6 cms distally and proximally, we carried out a blind distal bypass (less than 1%).

Technique


The operative procedures were carried mostly by epidural anaesthesia (80%), general anaesthesia (15%), spinal anaesthesia (5%). All surgical procedures were done by one team which included the main vascular surgeon and his associates. 250 femoro popliteal bypass procedures were done using PTFE (Goretex®) graft mostly 7 mm in diameter (Fig. 1). The proximal anastomosis was end to side to common femoral artery and the distal anastomosis end to side was done to popliteal artery above the knee joint.

398 distal bypasses was carried out using reversed autologous saphenous vein and 2 distal bypasses using tapered PTFE (Goretex®) graft. We did 250 femoroposterior tibial bypass procedure (Fig. 2), 140 femoro anterior tibial bypass procedure (Fig. 3) and 10 femoro peroneal bypass procedure (Fig. 4). All grafts were placed deep to deep fascia to avoid any infection. We used 6-0prolene for distal bypasses and 5-PTFE (Goretex®) suture for graft anastomosis. Occasionally, we did local endartectomy of the artery to improve the flow. Needed patients underwent local amputation of the gangrenous region after the bypass graft procedure. During surgery all patients were heparinised and none post operatively except for prophylactic low molecular weight heparin to prevent DVT.

Fig 2
Fig 2 : Femoro-posterior tibial bypass graft using autologous saphenous vein


Fig 3
Fig 3 : Graft using autologous saphenous vein


Fig 4
Fig 4 : Femoro peroneal bypass graft using autologus saphenous vein


Post operatively all patients were given enteric coated aspirin on a long term basis. No post op anticoagulants were given by oral route. No peri-operative angiogram was carried out.

Follow up and statistics

The patients were evaluated at 3 months and 12 months interval. In addition follow up of all patients were performed yearly thereafter. Graft patency was assessed by palpation of distal pulses and doppler pressure measurements. Arteriogram was performed if there was any question as to patency. Endpoints for follow up were death of the patient, major amputation, occlusion of graft. A few patients were lost to follow up.

Primary patency is defined as uninterrupted patency without the need for intervention of any kind. All results of patency and limb salvage were calculated and standard errors were estimated.

RESULTS

Peri-operative morbidity and graft failure

26 patients (4%) died within the first 30 daysafter the operation due to various reasons. Other serious but nonfatal complications included myocardial infarction, DVT and renal failure and pneumonia.

Early graft infection was seen 2% of all patients operated and responded well with aggressive antibiotic therapy. Only 2 infected PTFE graft necessitated removal of graft followed by major amputation. During the first month after operation, 40 grafts occluded (6.1%). No further procedure was carried out for these patients following occlusion as most of the patients refused re-operation for various reasons. All occluded graft patients were given post operative anticoagulation with IV heparin followed by oral anti-coagulants.

Long term patency

The life table primary patency results for all grafts are seen in Graph 1. The primary patency rate is 80% at one year for above knee grafts and 60% for below knee grafts.

The five year patency rate for above knee graft is about 67% and 47% for below knee grafts. The grafts of patients operated on for gangrene in young patients with Buergars disease showed worse results than compared to patient with diabetic vascular problems. When there is poor distal run off the graft patency was poor. Superior patency was achieved when the distal anastomosis was to anterior tibial artery followed by posterior tibial and peroneal arteries.

Graph 1
Graph 1 : Graph showing patency


Late death

Limb salvage

Including the perioperative death the five year survival rate of the 650 patients was about 60%. Patients with diabetes had a lower 5 year survival rate than those without diabetes.

Despite the presence of a patent graft 13 patients (2%) underwent major amputation due to graft infections. Major amputation was necessary due to graft failure at a later stage in 20 patients (3%). The cumulative limb salvage rate for all infra inguinal bypass procedures is 90% for femoro popliteal bypass and 75% for distal bypass at 1 year and 73% at 5 years for femoro popliteal and 51% at 5 years for femoro distal bypass procedures (Graphs II).

Graph 2
Graph 2 : Graph showing limb salvage


DISCUSSION

One of the most important determinants for early outcome of infra inguinal reconstructions is the outflow resistance as judged by the angiographic run off status. Preoperative selection of patients and exclusion from operative consideration of cases with poor run off with results in a low early failure rate. During the study period all patients with severe vascular disease with impendingamputation were considered to have a chance for limb salvage by a reconstructive procedure even if the run off is poor.

Despite a high rate of graft failure acceptable limb salvage rates can be achieved. The incidence of acute post operative infra inguinal bypass failure ranges from 5% to 9% as reported by Mills and associates. Another study conducted by Marin, Veith and associates reported early graft failure rate ranging from 5% to 10%. Marrin and Veith always emphasized the value of completion angiogram but in our study we never carried out the completion angiogram. As pointed out by Veith et al there are some patients who need a graft for a limited time only until a peripheral lesion has healed. However, it seems to be important to identify those patients most likely not to benefit from revascularisation. Absence of distal run off has disastrous results for both patency and limb salvage even within the first month after operation.

REFERENCES

1.Veith FJ, Gupta SK, Ascer E, et al. Six year prospective multicenter study comparing autologous saphenous vein and expanded PTFE grafts in infra inguinal arterial reconstruction. J Vasc Surgery 1986; 3 : 104-14.

2.Ascer E, Veith FJ, Gupta SK, et al. Six years experience with expanded PTFE arterial grafts for limb salvage. J Cardio Vascular Surgery (Torino) 1985; 26 : 468-72.

3.Ascer E, Collier P, Gupta SK, Veith FJ. Re-operation for PTFE bypass failure, the importance of distal outflow site and operative technique in determining outcome. J Vasc Surg 1989; 5 : 298-310.

4.Rutherford RB, Jones DN, Bergents SE, et al. Factors affecting the patency of infra inguinal bypass. J Vasc Surg 1988; 8 : 236-46.



To Section TOC
Sponsor-Dr.Reddy's Lab