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The aetiology of vein graft stenosis is poorly understood. In a cohort of 88 patients, the mean internal diameter of the vein grafts that developed a stenosis was 3.7 (3.1-4.2) mm compared to 4.7 (4.4-5.0) mm in those that did not (p = 0.006). The mean lowest compliance value in the 11 patients who developed a stenosis was 0.1 (0.07-0.13) % per mmHg compared to 0.21 (0.19-0.23) % per mmHg in the rest (p < 0.001). The presence of vein incompetence, site of tributaries or valves and the degree of endothelial cell loss were not related to the development of vein graft stenoses. The presence of a macrophage infiltrate (p < 0.001), lymphocyte infiltrate (p < 0.025) and subendothelial smooth muscle cells (p < 0.05) were all significantly more common in those grafts that developed a stenosis. Vein quality is an important factor in the development of graft stenoses.

The ability of vein to dilate may allow smaller veins to be used for bypass if this change could be predicted. Sixty patients undergoing femorodistal popliteal or infrapopliteal bypass have had their long saphenous vein studied. Diameter measurements of the long saphenous vein have been performed using an ATL Duplex scanner at the groin, mid-thigh and knee. Measurements were performed preoperatively both at rest and with a venous occlusion cuff to dilate the vein and subsequently at 7 days and 3, 6, 9, 12 months after implantation. The mean diameter of the vein at the mid thigh was 4.2 mm non dilated, 5.1 mm with occlusion, 5.4 mm 7 days postoperatively and 5.5 mm at 12 months (p < 0.01 ANOVA). The mean diameter of the vein at the knee was 3.8 mm non-dilated, 4.8 mm with occlusion, 4.8 mm at 7 days and 5.0 mm at 12 months after operation (p < 0.01 ANOVA). If the minimum resting internal diameter of vein regarded as being suitable for bypass was 3 mm, this technique would have increased the vein utilisation rate by 22%. These results show that by using a technique of venous occlusion at the time of preoperative vein mapping the adaptive response of the vein can be predicted and this can result in an increased rate of vein utilisation.

Various vein factors affect the outcome of femorodistal bypass using vein in the treatment of lower limb ischaemia. In this review, the effect of factors such as vein size, compliance and morphology are discussed.

The criteria for identifying the "at-risk" femorodistal bypass are controversial. Eighty-eight patients were entered into a surveillance programme using ankle-brachial pressure indices (ABPI), colour Duplex and intraarterial digital subtraction angiography (IADSA). Changes in ABPI of more than 0.1 identified 12/22 (51%) grafts thought to be "at-risk". In the 88 grafts, a PMV (peak mean velocity) < 45 cm per second had a sensitivity and specificity of 55 and 85% compared to 91 and 95% if a PMV < 45 cm per second and a V2/V1 ratio of greater than 2 was used to identify the 22 grafts "at-risk". In total 341 examinations were performed, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy for impedance analysis was 70, 90, 48, 97 and 91% respectively, compared to 93, 97, 77, 99 and 97% for colour Duplex in identifying the "at-risk" grafts. Between 6 weeks and 12 months the mean PMV was seen to drop by 29% and the mean impedance score by 19%. The most sensitive mode of non-invasive graft surveillance is colour Duplex providing the assessment involves both a measurement of the velocity ratio and the absolute velocity. However, impedance analysis is a better screening test than ABPI and PMV.

Between 1 January 1985 and 31 December 1991, 2426 patients underwent arterial surgery. Three hundred and seventy one reoperations were performed on 258 patients within 30 days of the initial procedure. One hundred and ninety three (52%) of the operations were attempted revascularisations, 95 (26%) were amputations and 58 (16%) were to control bleeding. One hundred and sixty nine (66%) of first operations were successful, but 76 patients required a further 113 reoperations. The mortality of reoperation was 16%, while the mortality of patients not requiring reoperation was 9% (p < 0.01). The mean hospital stay in days was higher in patients requiring reoperation (p < 0.05). Where appropriate, patients should be informed of the significant incidence of reoperation and reoperative mortality after vascular surgery. The increased hospital stay in reoperated patients has financial implications.

Cerebral hyperperfusion syndrome after carotid endarterectomy is rare. Unilateral headache, confusion, seizures or focal neurological signs may occur and intracranial haemorrhage may be a terminal event. We report a case of hyperperfusion accompanied by transient hemiparesis. The changes in cerebral perfusion were documented using transcranial Doppler sonography which helped to make the diagnosis.

Random vein samples taken prior to bypass surgery have shown certain pathological features. Long saphenous vein was taken from the groin (proximal) and knee to mid-calf (distal) of 85 patients undergoing femoro-distal bypass over a 2-year period. During this period only four patients had cephalic arm vein used; this was also studied. Histological examination was performed using haematoxylin and eosin and van Geison stains. Intimal hyperplasia was seen in 62 (73%) proximal and 74 (87%) distal samples. There were significantly more distal veins with moderate to severe focal hyperplasia and circular muscle hypertrophy (p < 0.05 and p < 0.001). Changes of diffuse intimal hyperplasia were seen in three of the cephalic veins. Muscle hypertrophy occurred in 58 (68%) of proximal segments compared to 75 (88%) of distal segments (p < 0.005). This study shows that significant pathological changes are seen in long saphenous and cephalic veins thought to be "normal". These changes are more evident in the distal long saphenous vein. These changes may have a significant effect on the outcome of vein bypass.

Fifty patients who have undergone femorodistal bypass surgery have been followed up using impedance analysis and colour Duplex, with biplanar intraarterial digital subtraction angiography being used as the arbiter to define "at risk" grafts. An impedance score of 0.49 (0.43-0.55) was found in the "at risk" grafts, all of which underwent an interventional procedure compared to 0.39 (0.36-0.42) (p = 0.003, Mann-Whitney U test) in those with no problem. In total, 166 examinations were performed. The sensitivity and specificity were all greater than 91% when compared to angiography. Impedance analysis is simple, non-invasive, easy to perform and it takes only 10 min to complete the examination. In view of the results obtained using impedance analysis in comparison with Duplex scanning, we suggest that non-invasive impedance is a suitable alternative to colour Duplex for graft surveillance (mean +95% confidence interval).

Data was reviewed on patients presenting with lower limb-threatening ischaemia to a single vascular unit between September 1984 and December 1990. Three hundred and thirty patients underwent either femoro-popliteal or femoro-infrapopliteal reconstructive surgery and 316 primary amputations were performed on 281 patients. Sixty-three secondary amputations were performed following a femoro-distal bypass failure. The below-knee amputation to above-knee amputation ratio (BKA/AKA) was 1.0 in the primary amputation group to 0.91 in the secondary amputation group. A direct comparison cannot be made as the patients represent two separate clinical groups. The ratio of reconstructive operations to primary amputations more than doubled between the first and second halves of the study. The BKA:AKA ratio in the secondary amputation group and the total number of secondary amputations remained relatively constant. This study supports the view that previous femoro-distal surgery does not adversely affect the overall outcome of amputation.

In 30 patients undergoing femoro-distal bypass the effect of papaverine and praxilene on blood flow in the graft was measured. The mean resting flow was 129 ml min-1 (range: 91-167) and after papaverine was 202 ml min-1 (142-262) and after praxilene was 205 ml min-1 (143-267). Praxilene has a similar effect to papaverine in the augmentation of blood flow, and further investigation is needed to see if long-term praxilene administration might improve graft survival.

The diameter of the long saphenous vein has been shown to affect the outcome of femoro-distal bypass. Many surgeons regard a vein with a diameter of less than 3 mm as being unsuitable. The long saphenous vein was studied in 35 patients undergoing femoro-distal bypass. Diameter measurements of the vein were performed using an ATL duplex scanner at the groin, mid-thigh and knee. Measurements were performed preoperatively both at rest and with a venous occlusion cuff to dilate the vein, and subsequently at 7 days and 2 months after implantation. The mean diameter of the vein at the mid-thigh was 4.1 mm non-dilated, 5.1 mm with occlusion, 5.0 mm 7 days postoperatively and 5.2 mm at 2 months (ANOVA, p less than 0.05). The mean diameter of the vein at the knee was 3.9 mm non-dilated, 4.8 mm with occlusion, 4.8 mm at 7 days and 4.9 mm at 2 months after operation (ANOVA, p less than 0.025). In all five patients whose preoperative resting vein diameter at the knee or mid-thigh was less than 3 mm, preoperative dilatation occurred, such that the diameter became greater than 3 mm. These results suggest that by using a technique of venous occlusion at the time of pre-operative vein mapping, the functional diameter of the vein can be predicted and vein utilisation may be increased.