Prospective randomized trial of woven versus collagen-impregnated knitted prosthetic Dacron grafts in aortoiliac surgery.

BACKGROUND: Despite the theoretical advantages of coating knitted grafts with a material designed to reduce blood loss, their performance has not been directly compared with woven grafts in a prospective randomized trial. The aim of this study was to compare the graft handling qualities and operative blood loss of the two types of arterial prosthesis, as well as complication rate and patient survival at 1 year. METHODS: A total of 267 consecutive patients having surgery for occlusive or aneurysmal disease of the aortoiliac arteries were randomized to receive woven (141 patients) or knitted collagen-impregnated Dacron (126 patients) grafts. Graft patency was assessed on discharge and at 1 year by duplex imaging. RESULTS: Mean(s.d.) intraoperative blood loss was statistically greater with woven grafts (1690(1424) ml) compared with knitted (1363(1172) ml) (P = 0.049). An insignificant 1-year increase in mean(s.d.) graft diameter of 1.2(0.2) mm was found at the distal anastomosis in the knitted group. There was no difference in graft patency between the groups and only one graft became infected. CONCLUSION: This study suggests that knitted and woven grafts have similar clinical performance and therefore the less expensive material (woven) should usually be selected unless haemorrhagic complications are anticipated.

Intraoperative heparinisation, blood loss and myocardial infarction during aortic aneurysm surgery: a Joint Vascular Research Group study.

OBJECTIVES: The primary aim of this prospective multi-centre study involving patients undergoing elective abdominal aortic aneurysm (AAA) surgery was to investigate the relationship between intraoperative intravenous heparinisation, blood loss during surgery and thrombotic complications. METHODS: Two hundred and eighty-four patients were randomised to receive intravenous heparin (n = 145) or no heparin (n = 139). Groups were evenly matched for age, sex, weight, aneurysm size, haemoglobin concentration, platelet counts and distal occlusive disease measured by ankle/brachial systolic pressure. RESULTS: There were no statistically significant differences in blood loss (median 1400 ml vs. 1500 ml; z = 0.02, p = 0.98, 95% C.I. = -200 to 200), blood transfused (4.0 units vs. 4.0 units; z = 1.09, p = 0.28, 95% C.I. = -1 to 0) or distal thrombosis between the two groups. However, analysis of the clinical outcome revealed that 5.7% of the non-heparin group but only 1.4% of the heparinised patients suffered a fatal perioperative myocardial infarction (MI); p < 0.05. All MI, including non fatal events, affected 8.5% and 2% respectively (p = 0.02). CONCLUSIONS: Heparin does not increase blood loss or the need for blood transfusion during surgery. Heparin is not necessary to prevent distal thrombosis when the aorta is cross clamped. The results of the study are consistent with the known mechanisms leading to intraoperative MI and strategies for its prevention. Intravenous heparin, given before aortic cross clamping, is an important prophylaxic against perioperative MI in relation to AAA surgery.

Coronary artery disease in patients with peripheral vascular disease.

For patients requiring peripheral vascular surgery, coronary artery disease is the major determinant of perioperative mortality and long-term survival. The management of coronary artery disease in these patients is controversial as no randomized blinded prospective studies have been conducted. Data on the prevalence, diagnosis and management are reviewed.

Accidental intra-arterial drug injection successfully treated with Iloprost.

A 35-year-old drug abuser inadvertently injected adulterated heroin into her left femoral artery and presented with critical ischaemia of her left leg. Treatment with intravenous Iloprost, a stable prostacyclin analogue, combined with Heparin, produced a dramatic improvement in her circulation within 4 h.

Reasons to strip the long saphenous vein.

Whether the long saphenous vein (LSV) should be stripped or not remains contentious. Varicography in patients with recurrent varicose veins frequently demonstrates an intact LSV. A series of 41 varicograms have been reviewed to find how often an unstripped LSV is associated with recurrence. Thirty-two patients, 22 female and 10 male, of mean age 49 years (33-78 years) were investigated. Forty-one limbs had previously had high saphenous ligation, yet still had clinical and ultrasound evidence of superficial venous reflux from a source above the knee. The mean interval between first and the last operations was 16 years (2-33 years). An intact LSV in some part of the thigh was present in 22/41 limbs (54%). Midthigh perforator incompetence (MTPI) via the unstripped LSV was present in 14/41 limbs (34%) and MTPI direct from femoral vein to a superficial varix occurred in 6/41 limbs (15%). The commonest problem is a residual communication at the groin found at operation in 80 p. cent of limbs. Accurate saphenofemoral ligation is crucial but we suggest that recurrence from MTPI via the intact LSV, and the possibility of recanalisation from the upper end of the intact LSV to the femoral vein are arguments for continued stripping.

Early diagnosis of femorodistal graft stenoses.

Detection and early correction of stenoses following femorodistal bypass grafting may prevent graft occlusion. We studied 43 grafts (36 saphenous vein and 7 human umbilical vein) prospectively by peroperative angiography and then by clinical assessment, post-exercise Doppler ankle pressures and digital subtraction angiography at 1 week, 3 months, 6 months and 1 year. There were 11 grafts inserted for critical ischaemia, 16 for rest pain and 16 for disabling claudication. Four patients died within the year with five patient grafts and these were excluded from the final results. Eight grafts failed during the first year; four within 1 month and a further four subsequently, with no warning alteration of symptoms, ankle Doppler pressure or digital subtraction angiography. Four additional grafts were jeopardized by symptomatic stenoses. Six grafts developed an asymptomatic stenosis of greater than 50 per cent without a change in exercising ankle Doppler pressure. Three symptomatic stenoses were successfully revised but the fourth occluded on conservative management. Three asymptomatic stenoses have also been successfully revised and three have been treated conservatively. Close surveillance of femorodistal grafts is justified by this study but a deterioration in ankle brachial Doppler index was only useful in the patients with recurrent symptoms and was unable to detect half the stenoses of greater than 50 per cent. The detection of these by intravenous digital subtraction angiography might help to avoid graft failure.

The use of varicography to identify the sources of incompetence in recurrent varicose veins.

We have studied patients with recurrent varicose veins which were incompletely controlled by a thigh tourniquet. We used varicography, (a phlebogram via the varices), to detect sites of incompetence. Thirty patients (mean age 46 years) were investigated, 38 limbs being subjected to varicography and surgery. A primary operation had been performed between 3 months and 30 years earlier. A non-thrombogenic contrast medium, sodium meglumine ioxaglate 320 (Hexabix 320) was used. Metal markers were placed alongside the limb to identify the site of perforating veins on the phlebograms. The principal value of the technique was in the identification of mid-thigh perforator incompetence (MTPI) as we cannot diagnose this accurately by clinical or Doppler-ultrasound examination. Varicography demonstrated MTPI in 15/38 limbs (39%) and in only one thigh was this not confirmed at exploration. Varicography can demonstrate short saphenous incompetence and this was mainly of value in 3 patients who had previously undergone attempted short saphenous ligation; in all 3 the short saphenous vein was present and had not been ligated. The technique was less useful in demonstrating recurrence in the groin. Overall varicography influenced the operation performed in 17/38 limbs (45%), its main value being in the diagnosis of MTPI.

Early aneurysmal degeneration of human umbilical vein bypass grafts.

Three cases of early aneurysmal degeneration of modified human umbilical vein (HUV) grafts in the femorodistal segment are described. One such graft is the first reported with multiple true aneurysms. The pathology and management of this complication is discussed.