Prevention of deep venous thrombosis in vascular surgical procedures by LMW-heparin.

The risk of Deep Venous Thrombosis (DVT) in the immediate postoperative period varies from 0.8 to 96% of cases depending on major or minor operations and on age of patients. We have employed 8,000 I.U. AXa/daily of LMW-Heparin injected subcutaneously from one day preoperatively and prolonged for 8 days after surgical procedures in 40 patients operated upon by an aorto-femoral bypass in 25 cases, a femoro-popliteal below the knee in 8 and an extra-anatomical bypass in 7. The onset of DVP in the lower limbs was investigated by clinical examination, venous Doppler pressure evaluation, waveform analysis and echotomography and the 125I-Fibrinogen uptake test. There was no intraoperative increased bleeding and the preclotting of the prosthetic grafts was inaffected. A DVT was detected during the second postoperative day, by means of the 125I-Fibrinogen test in the calf of only one patient (1/40-2.5%), submitted to an aorto-bifemoral bypass, in whom the clinical pattern and ultrasound investigations were negative. The single daily subcutaneous administration has never caused side effects in the site of injection and it seems a real improvement in the heparin treatment. These results emphasize the advantage of the use of LMW-Heparins in patients submitted to arterial surgical reconstructions of the lower limbs for the prevention of the DVT.

Arterial repair of the lower limbs: prevention of prosthetic grafts occlusion by LMW-heparin.

The postoperative thrombosis of prosthetic grafts may be due to many factors: technical errors, poor run-off, prosthetic material, graft length, trauma by subcutaneous tunnellization or repeated microtrauma across the joint areas, evolution of atherosclerotic lesions, emorheological changes. In 50 patients submitted to surgical arterial repair of the lower limbs, we have employed 8,000 I.U. AXa/daily of LMW-Heparin, injected subcutaneously for 6 months after the operations to prevent immediate and late thrombosis. During the follow-up, one patient died, four stopped any treatment and in two the medication was changed. Hence our results are based on 43 cases: 10 patients operated upon by aorto-femoral bypass, 19 femoro-popliteal and 14 extra-anatomical procedures. During the follow-up all the patients were investigated by ultrasounds (pressure measurement, waveform analysis and duplex scanning echotomography); moreover 13/43 (30%) were studied by angioscintigraphy and 11/43 (25.5%) by a conventional or digital subtraction angiography. Thrombosis of the grafts at one year term occurred in none aorto-femoral, in one femoro-popliteal (5.2%) and in one extra-anatomical bypass (7.1%). This figure compares favourably with the results obtained in our experience in the patients treated by a variety of drugs. In such group the incidence of occlusion is 3.9% in aorto-femoral, 9.3% in femoro-popliteal and 11% in extra-anatomical grafts. Those results emphasize the possibility to improve the patency of the grafts in the arterial repair of the lower limbs by LMW-Heparin overall in femoro-popliteal and extra-anatomical areas.

The salvage of the lower limbs: choice of the prosthetic material in femoro-distal and axillo-femoral bypass.

The choice of the prosthetic material in arterial surgery of patients with rest pain and/or impending gangrene of the lower limbs still presents several problems. The poor run-off, the small caliber of the distal vessels, the crossing of the joint areas and the length of the bypass may lead to early occlusion of the prosthesis. This experience is based on 268 femoro-distal (214 femoro-popliteal below the knee and 54 femoro-tibial) and on 121 axillo-femoral/popliteal bypasses (89 axillo-femoral, 28 axillo-bifemoral and 4 axillo-popliteal). In the 389 surgical procedures we have employed the autologous saphenous vein in 208 cases, Polytetrafluoroethylene (PTFE) straight or tapered in 66, PTFE external supported (EXS) in 33, Dacron in 12, homologous saphenous vein in 7 and PTFE EXS Thin Wall in 5. In 58 cases a composite graft (autologous saphenous vein plus synthetic prosthesis) was used. The cumulative long term (12-96 months) patency is 75.96% for autologous saphenous vein bypass, 62.12% for PTFE, 75.75% for PTFE EXS, 41.66% for Dacron, 42.85% for homologous saphenous vein and 84.48% for the composite graft. All the PTFE EXS Thin Wall grafts are still patent (12 months).(ABSTRACT TRUNCATED AT 250 WORDS)

Doppler C.W. study of the lower limb venous hemodynamics during pregnancy and prevention of thrombotic complications.

Thirty-two women (14 primiparae and 18 multiparae) were submitted to clinical and ultrasound investigations during the 1st, 2nd and 3rd quarter of pregnancy and after childbirth, for the evaluation of the lower limb venous system. An increase of the venous pressure in the standing position was present in all the women during the last quarter of pregnancy. In 14 cases varices (6 primiparae, 8 multiparae) with incontinence of the saphenous-femoral valve in 10 (3 primiparae, 7 multiparae), were detected during pregnancy. In these patients a compressive bandage associated, in selected cases, to calcium-heparin therapy (25000 IU/daily) was employed. After childbirth the venous pressure resumed physiological values in 20 of the 32 women while the varices remained in 12 cases. No thrombotic complication of the superficial and/or deep venous system neither hemorrhagic episodes related to calcium-heparin therapy occurred.

Isolated symptomatic lesions of the vertebral artery: cure after surgical repair.

Nine patients with uni-or bilateral stenosis of vertebral arteries, not associated with other lesions of supraaortic trunks are reported. They showed a vertebrobasilar insufficiency syndrome not due to other assessable causes. Seven of them underwent surgical treatment always as reimplantation of the vertebral into the subclavian artery. The procedure was unilateral also in cases with bilateral lesions. In all 7 patients a favourable result was obtained: 5 patients recovered completely and 2 showed a marked improvement. The study demonstrates that the surgical repair of symptomatic unilateral lesions of vertebral arteries is able to cure the vertebrobasilar insufficiency syndrome.

Arterial reconstruction of the limbs in poor run off conditions and surgical repair of vena cava with expanded PTFE (IMPRA-grafts).

Seventy eight arterial and venous reconstructions using expanded microporous PTFE (IMPRA-grafts) are reported. This prosthetic material has been employed, by itself or in addition to autogenous vein segments when the saphenous vein was not available or inadequate in length or quality. Long term results show that 83% of vascular repairs are patent up to 36 months post-operatively. Since the prosthesis has been used in vena cava reconstructions, in patients with severe impairment of the distal arterial tree and in some cases in whom previous surgical treatment had failed, these results are favorable and encouraging.