K. Varty

Chronic critical leg ischaemia must be redefined.

The Second European Consensus Document on Chronic Critical Leg Ischaemia defines critical limb ischaemia in non-diabetic patients as rest pain or tissue necrosis (ulceration or gangrene) with an ankle systolic pressure (ASP) of less than or equal to 50 mmHg, or a toe pressure of less than or equal to 30 mmHg. The aim of this study was to investigate whether this definition is able to predict the outcome of patients with severe lower limb ischaemia and thus to determine the relevance of the definition in clinical practice. We have analysed 148 severely ischaemic limbs in 133 non-diabetic patients who presented with rest pain, tissue necrosis or a combination of these symptoms. Fifty-one percent of these limbs fulfilled the current definition with an ASP < or = 50 mmHg; 49% had an ASP > 50 mmHg and were thus not defined as critically ischaemic according to the current definition. We have compared actuarial limb salvage and mortality rates in patients with an ASP < or = 50 mmHg to those patients with an ASP > 50 mmHg. The 1 year limb salvage and mortality rates for ischaemic limbs fulfilling the European Consensus Document criteria were 78.7 and 36.7% respectively, compared to rates of 73.9 and 17.3% in patients who were not defined as critically ischaemic under the current definition. There were no significant differences between 1 year limb salvage or mortality rates between the two patients groups (p = 0.843, 0.078, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Infrapoliteal percutaneous transluminal angioplasty: A safe and successful procedure

AIM To review outcome of 40 consecutive infrapopliteal percutaneous transluminal angioplasty (PTA) procedures performed over a 65 month period. CHIEF OUTCOME MEASURES The indication for PTA was intermittent claudication in 20 (50%) cases and rest pain, ulceration or gangrene in the remainder. RESULTS There was one technical failure; the remaining 39 limbs were all clinically improved by 24 h and this improvement was maintained at 3 months in 36 (90%). There were no deaths nor limb loss related to PTA and 2 embolic complications were successfully treated percutaneously. The primary and secondary symptomatic patencies at 24 months were 59 and 79% respectively. The actuarial limb salvage rate at 1 year for the 20 limbs presenting with critical ischaemia was 77%, and 10 of the 14 procedures performed for ulceration or gangrene resulted in healing with only minor surgical intervention. CONCLUSIONS With modern endovascular techniques, infrapopliteal PTA is a safe, worthwhile and durable procedure.

Selection of Patients with Critical Limb Ischaemia for Femorodistal Vein Bypass

The merits of an aggressive policy of distal reconstruction have been questioned by some observers. To determine the factors affecting graft patency and mortality, we analysed 78 consecutive infragenicular femorodistal vein grafts performed in 72 patients with critical limb ischaemia. The primary, primary assisted and secondary graft patency rates at 36 months were 29, 57 and 64%, respectively. The limb salvage and patient survival rates at 36 months were 67 and 74%, respectively. Univariate analysis (log-rank test) was performed to identify factors affecting graft patency, limb salvage and mortality at 1 month (perioperative) and 1 year. Independent variables of age, sex, diabetes, presentation, level of anastomosis and vein technique (reversed or in situ) did not affect graft patency. The ankle systolic pressure did not predict graft patency but was an independent variable affecting mortality (p = 0.047), as did diabetes (p = 0.019). These results show that excellent limb salvage can be successfully achieved in severely ischaemic patients by adopting an aggressive approach to femorodistal bypass, and that age, gender and poor medical condition are not contraindications to femorodistal bypass. The difference between the primary and primary assisted patency rates in this series is dramatic and reflects the impact of a vein graft surveillance programme in preventing graft occlusion.

Results of surgery and angioplasty for the treatment of chronic severe lower limb ischaemia

OBJECTIVE To aims of this study was to assess and compare the efficacy of PTA and surgery in the treatment of severe lower limb ischaemia. DESIGN Prospective 12-month study of 180 consecutive patients with severe chronic lower limb ischaemia. METHODS PTA was used as first line therapy whenever possible and appropriate. Surgical revascularisation, primary amputation and conservative therapy were used in eh remaining patients. Patient survival and limb salvage were derived using life table analysis. RESULTS Revascularisation was attempted in 135 (75%) patients, with PTA in 82 (46%), surgery in 19 (27%) and a combination of both in four (2%). Overall 12-month survival and limb salvage was 75% and 71%, respectively. Surgery and PTA had significantly higher survival rates (91% and 78%) than primary amputation or conservative therapy (57% and 52%) (p < 0.0001 log rank test). Revascularisation with either surgery or PTA achieved the same limb salvage rate of 76%. CONCLUSION A large proportion of patients with severe chronic lower limb ischaemia can be managed by PTA. THis management strategy produces a clinically effective outcome at 1-year.

The histopathology of infrainguinal vein graft stenoses

The precise histopathological nature of vein graft stenoses is unclear. Some authors have suggested that these lesions are due to intimal hyperplasia and others have claimed that they are fibrous strictures. The aim of this study was to determine the histological nature of infrainguinal vein graft stenoses by examining sections of vein grafts that had developed stenoses and had been surgically revised. This was performed using a combined anti-smooth muscle actin/Millers elastin stain. The results show that vein graft stenoses are due to intimal hyperplasia whereby smooth muscle cells proliferate and cause thickening of the intimal layer.

The development of an in vitro flow model of human saphenous vein graft intimal hyperplasia

Objective : Although the role of blood flow has been investigated in animal models of intimal hyperplasia, there have been no detailed studies in intact human vein owing to the difficulties in designing a suitable laboratory model. The aim of this study was to develop a flow model of human vein graft intimal hyperplasia. Methods : Organ cultures of human saphenous vein were exposed to laminar flow by culturing in a closed circulatory system under predetermined conditions of venous and arterial shear stress for 14 days. Following fixation and processing, paraffin sections were immunostained and neointimal thicknesses measured. Results : It was found that arterial flow completely inhibited neointima formation, but venous flow only partly suppressed the response when compared with vein cultured under static conditions. These results are in agreement with previous in vivo studies in a primate graft model, where increased shear stress inhibited intimal proliferation. Conclusion : The endothelial cell is believed to be the key mediator of haemodynamic effects which influence smooth muscle cell proliferation, and the flow rig developed in this study offers the potential to study inter-cellular interactions within the intact vessel. Furthermore, this method provides the facility to study the effects of different flow conditions on segments of vein from the same patient. This model has scope for further development and sophistication which may ultimately lead to increasing our understanding of the aetiology of vein graft stenoses, and hence formulation of preventative strategies.

Infragenicular in situ vein bypass graft occlusion: a multivariate risk factor analysis.

Early postoperative thrombosis and the later development of graft stenoses are the two major causes of vein bypass graft failure. The risk factors for both these outcomes were analysed in a multivariate analysis of 82 consecutive infragenicular in situ vein grafts. Twenty-four grafts failed within 30 days but eight were successfully revised. Technical errors accounted for six of the failures. A multivariate analysis revealed graft resistance > 1.4 peripheral resistance units (odds ratio 5.8, 95% C.I. 1.6-20) as the only independent risk factor for early graft failure. Eighteen grafts (27%) developed a stenosis most commonly in the distal third of the graft (46%). Poor quality, small diameter vein was the only independent risk factor for graft stenosis (odds ratio 7, 95% C.I. 1.5-34). Composite vein grafts, where narrowed and thickened vein had been replaced, had a significantly lower stenosis rate (difference in proportions 0.41, 95% C.I. 0.1-0.8, Mann-Whitney U test).

Percutaneous angioplasty of the profunda femoris artery: a safe and effective endovascular technique.

The limb with an occluded superficial femoral artery (SFA) relies on the profunda collaterals for adequate perfusion. Frequently the profunda is also diseased exacerbating the limb ischaemia. We have used percutaneous transluminal angioplasty (PTA) of the profunda increasingly in recent years to treat such patients. In 28 limbs there was one technical failure, no major complications and six minor wound haematomas. A combination of SFA and profunda PTA was used in 11 patients. Ten of these became asymptomatic and one improved. In 16 patients a long SFA occlusion was unsuitable for PTA. An iliac and profunda PTA was performed in six of these, with resolution of (three) or significant improvement in (three) symptoms. Profunda PTA alone was used in the remaining 10 patients who constituted a high risk elderly group all with limb threatening or disabling ischaemia. Symptomatic improvement in seven of these enabled surgery to be avoided. A bypass procedure was performed in the three patients who failed to improve. Poor run-off (< one healthy calf vessel) was the major factor limiting the effectiveness of profunda PTA in these patients. Profunda PTA is a safe and effective procedure of particular value in high risk patients with a long SFA occlusion and at least one healthy calf vessel run-off.

A Quantitative Study of Long Saphenous Vein Morphology in Patients Undergoing Arterial Surgery

Objective: To quantify the incidence and extent of structural changes present in the long saphenous vein of patients with arterial disease. Design: Observational study of saphenous vein morphology. Setting: Departments of Surgery and Pathology, Leicester Royal Infirmary. Patients: Sixty vein biopsies from patients undergoing arterial surgery. Main outcome measures: Intimal and medial thickness and morphology. Results: Smooth muscle cell hyperplasia, elastosis and fibrosis contributed to intimal thickening (> 10 μm) in 87% of veins. This was frequently associated with medial longitudinal muscle hypertrophy. Intimal thickness had a skewed distribution with a median (range) of 33 (8–381) μm, The upper limit of the normal range was 200 μm. The median (range) medial thickness was 293 (131–468) μm. Conclusions: Intimal thickening is common in the long saphenous vein of patients undergoing arterial surgery but is extensive in only a small proportion. The upper limit of the normal range was 200 μm.

Effects of the development of modern vascular services on amputation rates in Leicester, U.K.: A preliminary report

We have reviewed 3036 consecutive patients who underwent arterial reconstruction, percutaneous transluminal angioplasty, or a major amputation for lower limb peripheral vascular disease in Leicester between 1974 and 1990. Patient data were obtained from the Hospitals Activity Analysis database, which codes all patient discharges according to diagnosis and treatment. During this 17-year study period, 1132 patients have undergone arterial reconstruction, 706 patients have undergone percutaneous transluminal angioplasty, and 1198 patients have undergone major amputation. The results show that the number of arterial reconstructions and angioplasties for lower limb arterial occlusive disease has increased over the last 17 years. The total amputation rate has decreased slightly during the period studied, but overall the decrease has not been significant.