Biological mechanisms influencing prosthetic bypass graft patency: possible targets for modern graft design.

In recent years, ample attention has been directed towards the mechanisms that play a major role in the process of vascular graft failure, especially graft thrombosis and intimal narrowing have been highlighted. In this article, a survey is conducted into the key mechanisms of the biological processes of intimal hyperplasia and ultimate graft failure. The sequence of biochemical events that lead to thrombosis of grafts is used as a guideline to describe possible counteracting prosthetic surface interventions in each separate phase of the process.

Preservation for future use of the autologous saphenous vein during femoro-popliteal bypass surgery is inexpedient.

PURPOSE: To investigate the usefulness of greater saphenous vein preservation for future vascular reconstructions during femoro-popliteal bypass surgery. DESIGN: Post-hoc analysis of data acquired in a randomized multi-centre clinical trial comparing two different vascular prostheses (ClinicalTrials.gov ID: NCT 00523263). PATIENTS AND METHODS: The true frequency of ipsilateral saphenous vein use in subsequent femoro-popliteal and coronary bypass surgery was investigated through case-record analysis with a median follow-up of 60 months in 100 consecutive patients, that received a prosthetic femoro-popliteal bypass between 1996 and 2001. RESULTS: An ipsilateral secondary femoro-popliteal bypass was performed in 11 patients (11%) at a mean interval of 34 months (range 1-96). The ipsilateral saphenous vein was applied for these procedures in 8 cases (8%). The cumulative probability of receiving a subsequent bypass was 8% at 3 years and 10% at 5 years follow-up respectively. One patient (1%) underwent CABG at 8 years follow-up with the use of ipsilateral lower leg saphenous vein segments only. CONCLUSION: Preservation of the greater saphenous vein in supragenicular femoro-popliteal bypass surgery is not a valid argument for application of prosthetic material.

Human umbilical vein versus heparin-bonded polyester for femoro-popliteal bypass: 5-year results of a prospective randomized multicentre trial.

PURPOSE: To compare long-term patency of Heparin-Bonded Dacron (HBD) and Human Umbilical Vein (HUV) vascular prostheses in above-knee femoro-popliteal bypass surgery. DESIGN: A prospective randomized multi-centre clinical trial. PATIENTS AND METHODS: Femoro-popliteal bypasses were performed in 129 patients between 1996 and 2001. After randomization 70 patients received an HUV and 59 an HBD prosthesis. Patients were followed up every three months during the first postoperative year and yearly thereafter. The median follow-up was 60 months (range 3-96 months). Graft occlusions were detected by duplex scanning, angiography or surgical exploration. RESULTS: The cumulative primary patency rates were 79%, 66% and 58% at 1, 3 and 5 years postoperatively. Primary patency rates for HUV were 74%, 64% and 58% at 1, 3 and 5 years and 84%, 68% and 58% for HBD, respectively (log-rank test, p=0.745). Overall secondary patency rates were 82%, 72% and 61% at 1, 3 and 5 years postoperatively. The overall cumulative limb salvage at 5 years follow-up was 89% (CI 80%-91%) and was not dependent on graft type. Smoking (p=0.019), number of patent crural arteries (p=0.030) and previous cerebro-vascular events (p=0.030) were significant predictors of graft occlusion. CONCLUSION: There was no difference in long-term graft performance between HUV and HBD for above knee infrainguinal bypass.

Arterial reconstruction for subclavian obstructive disease: a comparison of extrathoracic procedures.

OBJECTIVES: Comparison of the immediate and long-term results of three different extrathoracic arterial reconstruction procedures for subclavian obstructive disease. DESIGN: Retrospective analysis of 51 extrathoracic subclavian artery reconstructions in 49 patients performed in a single centre over an 18-year period (mean follow-up 64 months, range 3-192). METHODS: Carotid-subclavian bypass (CSB, n = 21), subclavian-carotid transposition (SCT, n = 21) and subclavian-subclavian or axillo-axillary cross-over bypass (COB, n = 9) was performed. Upper extremity ischaemic complaints were present in 45/49 patients (92%) and vertebrobasilar insufficiency in 25/49 patients (51%). Symptom relief, improvement of haemodynamic parameters and graft patency were compared. RESULTS: Operation time was significantly shorter (p < 0.001, t-test) in SCT (80 +/- 5 min) compared to CSB (112 +/- 7 min) and COB (116 +/- 6 min). Symptom relief and improvement of haemodynamic parameters were similar for all groups. There were no differences in morbidity rate and there was no mortality. The cumulative patency of SCT was significantly better with 100% at 2, 5 and 10 years postoperatively compared to CSB (75.6%, 62.6% and 52.2%, respectively) (p < 0.005, log-rank test) and COB (76.5%, 63.7% and 63.7%, respectively) (p < 0.02, log-rank test). There was a tendency for a better patency in prosthetic grafts as compared to autologous vein grafts in CSB (NS, log-rank test). CONCLUSIONS: Satisfactory immediate and long-term results were obtained with all of the above techniques. When technically feasible, SCT is the procedure of choice for extrathoracic arterial reconstruction in subclavian obstructive disease.

Unilateral vascular reconstruction for iliac obstructive disease.

PURPOSE: Controversy exists regarding the extent of vascular reconstructive surgery in the presence of unilateral symptomatic iliac obstructive disease. This study reviews the results of unilateral iliac reconstruction, with special emphasis on the need for consecutive contralateral intervention. METHODS: The outcomes of 184 unilateral and 350 aortobilateral reconstructions for obstructive disease performed during the same period were retrospectively analyzed. Treatment allocation was based on hemodynamic parameters. Unilateral reconstruction was performed by a way of a retroperitoneal approach through a pararectal incision and bilateral reconstruction by way of a transperitoneal approach through a midline abdominal incision. RESULTS: Symptom relief, improvement of noninvasively measured parameters, and graft patency were similar after unilateral and bilateral reconstruction. Both groups had a 10-year primary patency rate greater than 80%. There were no differences in morbidity rate, although respiratory complications occurred more often after bilateral reconstruction. Mortality rates were 1.6% after unilateral reconstruction and 4.9% after bilateral reconstruction. Secondary contralateral reconstruction was performed in only 6% of the patients who underwent an initial unilateral operation. CONCLUSIONS: The unilateral vascular reconstruction for iliac obstructive disease is a well-tolerated procedure with an excellent long-term outcome. It is a valuable alternative to conventional aortobilateral reconstruction in carefully selected patients. Prophylactic reconstruction of an asymptomatic iliac stenosis without signs of significant hemodynamic impairment is most often not indicated.