Surgical treatment of the severely ischaemic leg: I. Survival rates

The Below-Knee Amputation: To Amputate or Palliate?

SIGNIFICANCE

A below-knee amputation (BKA) can be the most functional option for select patients with a diseased lower extremity and may offer a better quality of life than limb salvage in some patients.

RECENT ADVANCES

Because of advances in prosthetic technology, some patients may have a better quality of life with a BKA than a salvaged lower extremity. Those who cannot wear a prosthesis will do better with a poorly functioning leg. Understanding which patients will not benefit from an amputation helps ensure that a maximum of patients will continue ambulating.

CRITICAL ISSUES

We lack a thorough understanding of which patients will be more functional with a BKA than a salvaged extremity. Some will do better with a prosthesis, whereas others will do better with a poorly functioning peg leg. This is because so many amputees never wear their prosthesis.

FUTURE DIRECTIONS

A better understanding of patient selection and optimal operative technique would allow us to better council patients as to how to optimize their functional outcome. Over the past 30 years, a number of useful studies have been published regarding the BKA. However, recent advances in wound care, prosthetics, and medical care in general require a re-evaluation of the BKA within the limb salvage concept.

Tibioperoneal (outflow lesion) angioplasty can be used as primary treatment in 235 patients with critical limb ischemia: five-year follow-up

BACKGROUND

In a prospective, nonrandomized, consecutive series of tibioperoneal vessel angioplasty (TPVA), critical limb ischemia (CLI) patients' data were analyzed with regard to immediate and follow-up success.

METHODS AND RESULTS

TPVA was successful in 270 of 284 critically ischemic limbs (95%), with 167 limbs (59%) requiring dilatation of 333 ipsilateral inflow obstructions to access and successfully dilate 486 of 529 (92%) tibioperoneal lesions. A clinical success (relief of rest pain or improvement of lower-extremity blood flow) was attained in 270 limbs at risk (95%). Clinical 5-year follow-up of 215 of 221 successful CLI patients (97%) with 266 successfully revascularized limbs revealed that bypass surgery occurred in 8% and significant amputations in 9% of limbs; 91% of the limbs were salvaged. The cohort's probability of survival was 56%: 58% for Fontaine class III and 33% for class IV patients. Class III compared with class IV patients had significantly (P<0.05) fewer surgical bypasses (3% versus 16%) and amputations: above-knee, 1% versus 4%; below-knee, 3% versus 12%; and transmetatarsal, <1% versus 21%.

CONCLUSIONS

TPVA, often in combination with inflow lesions, is an effective primary treatment for critical limb ischemia. The poor cumulative survival reflects the existence of severe comorbidities, which could potentially be affected by aggressive and effective cardiovascular diagnostic and therapeutic strategies.

Association between age and survival following major amputation. The Scottish Vascular Audit Group

OBJECTIVES

To determine whether age is associated with survival following major amputation and whether this association is independent or simply reflects selection bias in amputation level.

DESIGN AND MATERIALS

Computer linkage of routine discharge and death data on the 2759 patients undergoing major amputation in Scotland between 1989 and 1993 for peripheral arterial disease.

METHODS

Cox's proportional hazards model and multivariate logistic regression analysis using death as the outcome variable and age, sex, urgency, amputation level and recent arterial reconstructive surgery as predictor variables.

RESULTS

Proximal amputation was more common in older patients. Survival was associated with both age (p < 0.001) and amputation level (p < 0.001). Age was an independent predictor of death at 30 days (p < 0.0001), 6 months (p < 0.001), 12 months (p < 0.0001) and 2 years (p < 0.0001) postoperation.

CONCLUSIONS

Survival following amputation was poor, with only half the patients alive at 2 years. Above-knee amputation was associated with poorer survival, presumably due to the presence of more severe and widespread disease, and was undertaken more commonly in older patients. However, age remained a predictor of survival after adjustment for amputation level. Higher early mortality suggest that a worse prognosis in elderly patients cannot be attributed wholly to actuarial considerations.

Femorotibial reconstructions for chronic critical leg ischaemia: influence on outcome by diabetes, gender and age

OBJECTIVES

To analyse the influence of risk factors on the outcome of femorotibial reconstructions for chronic critical leg ischaemia.

DESIGN

A longitudinal observational study of patients undergoing femorotibial reconstruction.

SETTING

A regional hospital and an academic referral centre.

MATERIALS

One hundred and eighty-eight patients undergoing 209 reconstructions to the tibial vessels for chronic critical leg ischaemia, 149 of them with in situ vein grafts.

CHIEF OUTCOME MEASURES

Graft patency, leg salvage and survival rates.

MAIN RESULTS

Severity of preoperative ischaemia influenced the immediate outcome of reconstruction. Increasing age did not influence graft patency, leg salvage or survival rates. A combination of female sex and diabetes was associated with low graft patency and leg salvage (52% and 42% at 18 months). Diabetes was associated with a decreased survival.

CONCLUSIONS

With proper patient selection, patency and leg salvage rates in older (> 80 years) patient groups with multiple risk factors justify an active reconstruction policy.

Multivariate Cox regression analysis of covariates for patency rates after femorodistal vein bypass grafting

Multivariate Cox regression analysis of patency rates for 750 consecutive femorodistal autogenous vein graftings for chronic lower limb ischemia showed that significant independent prognostic covariates were the type of graft (long saphenous or arm vein), presence of diabetes, and absence of a past history of myocardial ischemia. Analysis assumes that patients withdrawn with patent grafts due to death or loss to follow-up would have followed the same course as those who remain, and the degree to which this could distort results was studied. Patients who died with patent grafts were more likely to have had past myocardial ischemia and critical lower limb ischemia. Cox regression analysis for 600 operations after excluding patients who died with patent grafts then showed that significant independent covariates were the type of graft (long saphenous or arm vein) and indication (claudication or critical ischemia); then age, sex, hypertension, diabetes, myocardial ischemia, date of operation, surgeon, site of distal anastomosis, or first compared to repeat operations had no significant influence. Cox regression analysis helps determine which covariates influence graft patency rates, but results are affected by censored data, particularly from patients who die with patent grafts.

Extraperitoneal unilateral iliac artery bypass for chronic lower limb ischaemia

Extraperitoneal unilateral iliac artery bypass was used to treat chronic lower limb ischaemia in 105 patients (110 operations). This represented 20% of all operations for aorto-iliac disease. Unilateral iliac bypass was the preferred primary procedure for 99 operations, and was used to correct complications in one limb of a prior aortic bifurcation graft in the other 11. Ipsilateral femoropopliteal vein grafts were also performed in 45 legs (43%), prior to the iliac bypass in 18, as a synchronous operation in nine, and at a later date in 18 legs. This was a much higher proportion of combined operations than for patients by aortic bifurcation grafts (12%). Only 5 patients later required further proximal surgery, one for a blocked graft and four for contralateral iliac disease. The cumulative patency rate in surviving patients was 91% at 3 years. For the claudicants and for iliofemoral bypass operations, only one graft occluded, within 5 years, and no grafts occluded for operations where the superficial femoral artery was patent. The cumulative patency rates at 3 years were 85% for patients with critical ischaemia, 82% for ilioprofunda bypass operations, and 88% for operations where the superficial femoral artery was occluded. The cumulative foot-salvage rate in surviving patients initially treated for critical ischaemia was 77% at 3 years. The cumulative survival rate was 90% at 3 years. Extraperitoneal unilateral iliac bypass is now preferred as the primary operation for patients with apparent unilateral iliac disease causing severe ischaemia, if balloon dilatation is not appropriate or has failed.

Major amputation compared with graft occlusion as the end point for assessing results of bypass surgery in lower limb ischaemia

Cumulative graft patency rates calculated using graft occlusion as the end point are the standard method of presenting results of bypass surgery for lower limb ischaemia. The problems of using graft occlusion as the end point are that this is not easily documented and it gives no indication of the condition of the patient's limb after the graft occludes. The date of amputation is a well defined end point and it means treatment has failed. It is used to calculate cumulative limb salvage rates. Using the two techniques to assess different risk factors (age, calf vessel run-off, diabetes, position of distal anastomosis and hypertension), it was found that the limb salvage rate was a better indicator of patient progress. Whereas graft patency rates for diabetics and non-diabetics were similar (chi 2 = 0.8, P greater than 0.1), diabetics had a higher amputation rate and the limb salvage rate was significantly worse (chi 2 = 5.0, P less than 0.05). Cumulative survival is rarely presented in vascular series but it could be used as an indicator of the general condition of patients being selected for bypass surgery. The cumulative survival of diabetics was 23 per cent (s.e.m. +/- 12 per cent) at four years, while for non-diabetics this was 55 per cent (s.e.m. +/- 15 per cent), (chi 2 = 10.6, P less than 0.001). Diabetic patients have such different limb salvage and survival rates compared with non-diabetic patients that their results should be presented separately. A better indication of patient progress following bypass surgery is obtained if limb salvage rates and survival rates are reported as well as graft patency rates.

The effect of cessation of smoking on the accumulative survival rates of patients with symptomatic peripheral vascular disease

A study of the accumulative survival rates of 133 patients with symptomatic peripheral vascular disease was carried out comparing the survival rates of tobacco smokers and non-smokers. Within the smoking group, those who continued to smoke after the surgery were compared to those who ceased smoking. Of these patients with peripheral vascular disease, 86% were, or had been, smokers. Their survival rates were less than for those who had never been smokers. Of the smoking group, those who claimed to have ceased smoking had almost twice the chance of surviving five years than those who continued to smoke. From these data, we conclude that it is never too late to stop the smoking habit.

Comparative survival rates in symptomatic peripheral vascular disease and colorectal cancer

A comparative study of the accumulative five-year survival rates was made between patients with symptomatic peripheral vascular disease and patients with operable colorectal carcinoma. There was no significant difference between the two groups, but both had a significantly lower longevity than the normal population of the same average age (p less than 0.01). The patients' age at the time of treatment and their sex influenced survival in a similar manner in both colorectal cancer and peripheral vascular disease, there being no significant difference in the five-year survival curves in this comparison. A subset of individuals with colorectal cancer, those with Stage A lesions, were distinguished from the remainder. Their survival was significantly better than that of those patients with peripheral vascular disease (p less than 0.05) and was almost identical to that of the normal age-matched population.

Femoropopliteal bypass using polytetrafluoroethylene

Reinforced expanded polytetrafluoroethylene (PTFE) was used as a femoropopliteal bypass graft in 31 patients (37 operations). The indications were intermittent claudication (13 operations), severe ischaemia with rest pain or gangrene (20 operations), and prophylactic treatment of popliteal aneurysms (4 operations). The one-year accumulative patency rates were 75% for patients with intermittent claudication and 20% for patients with severe ischaemia. In three patients with claudication, graft thrombosis led to amputation in spite of attempted graft thrombectomy. These results compare unfavourably with our experience using autogenous vein, in which the one-year accumulative patency rates were 80% for claudication and 70% for severe ischaemia, and in which failure of the bypass graft for claudication rarely made the patient worse.

A comparison of proximal with distal arterial reconstruction in the treatment of advanced lower limb ischaemia

Elective arterial surgery for lower limb ischaemia due to chronic occlusive disease has been performed in 212 patients over a five-year period. Of this group, 93 patients were treated for limb-threatening ischaemia. The remainder were treated for intermittent claudication. The clinical and haemodynamic responses to surgery are analysed in this series of 93 patients. The results of proximal reconstruction, in terms of a living patient with patent graft and functional limb, were significantly better (75%) at one year than in patients undergoing distal segment reconstruction (45%). Successful aortoiliac surgery was associated with a mean increase in the ankle systolic pressure index of 0.36, comparied with 0.46 in the distal reconstruction group.

Surgical treatment of the severely ischaemic leg: II. Salvage rates

The salvage rates in 437 severely ischaemic legs (384 patients) treated by arterial reconstuction or by lumbar sympathectomy were studied by the life table method. The results were analysed in the surviving patients.

Following arterial reconstruction, the salvage rate was 70 per cent at 2 years and 60 per cent at 5 years. The results were similar for aortofemoral reconstruction and for femoropopliteal bypass grafting. Following aortofemoral reconstruction the outcome was better for endarterectomy procedures than for Dacron grafts. The salvage rate for femoropopliteal bypass grafts with patent tibial vessels was higher than for grafts to an isolated popliteal segment or for femorotibial grafts. Late occlusion of a reconstruction frequently did not necessitate major amputation, whereas several amputations were required in spite of a functioning reconstruction.

Following sympathectomy the salvage rate was 60 per cent from 1 year onwards. The results were better for tibial artery disease than for femoropopliteal or aortoiliac disease. Failed sympathectomy frequently led to major amputation of the leg or death of the patient.

The salvage rates after either reconstruction or sympathectomy were not influenced by age, sex or a prior history of clinical myocardial ischaemia, but the rates were worse in diabetics. The outcome of either operation was best when the procedure was performed for rest pain or ischaemic ulceration, satisfactory for limited gangrene but very poor for extensive gangrene.

The effect of smoking on the late patency of arterial reconstructions in the legs

In a retrospective study of 217 patients, smoking habits were related to the late patency rates of arterial reconstructions performed for ischaemia of the legs. Patients who had stopped smoking or who smoked no more than 5 cigarettes per day after the operation had late patency rates of approximately 90 per cent for aortofemoral reconstructions and 80 per cent for femoropopliteal vein grafts. Patients who continued to smoke more than 5 cigarettes per day were approximately three times more likely to block an aortofemoral reconstruction and four times more likely to block a femoropopliteal vein graft. The results were similar for males and females, for various age groups, for claudicants and patients with severe ischaemia and for aortofemoral endarterectomy and Dacron grafts. The late patency rate was approximately inversely proportional to the number of cigarettes smoked per day after the operation. There was no such correlation with the number smoked per day before the operation.