[External ionizing radiation on the prosthesis-arterial anastomosis for the prevention of intimal hyperplasia and study of biomechanical resistance. Experiments and results]. / Radiations ionisantes délivrées par voie externe sur l'anastomose prothéto-artérielle pour limiter l'hyperplasie intimale et étude de la résistance biomécanique. Expérimentations et résultats.

PURPOSE: To evaluate the use of external ionizing radiation for the prevention of intimal hyperplasia in anastomosis between PTFE and artery. METHODS: Bypass using a 6 mm PTFE was performed on a swine subrenal aorta with a distal conventional anastomosis (N = 35) associated (test group; N = 17) or not (control group; N = 18) with post-operative external radiation (20 Gy) on this anastomosis. At 45 days, histological studies and morphometric studies were performed on the aorta receiving the anastomosis. Two protocols were performed, the first protocol with standard analysis and the animals were randomly assigned to either group (test group; N = 11 and control group; N = 13) and the second protocol with test of extraction comparing the biomechanical resistance between the irradiated group (N = 6) and the control group (N = 5). RESULTS: Twenty-one animals survived the procedure in the first protocol, 11 in the second. The endothelium was restored in either group. Histological recasting was observed in the media after radiation with fibrosis and areas of necrosis. Intimal thickness was significantly lower after irradiation in the heel (P < 0.01), the head (P < 0.01) and the suture line (P < 0.001) of the artery in the first protocol. The intimal thickness was also significantly lower in the second protocol after radiation in the heel (P < 0.05) and the head of the artery (P < 0.05). There was no difference between the two groups comparing the resistance. CONCLUSION: After external irradiation, the thickness parameter of the intima decreased significantly in comparison with the control group with similar resistance. Media fibrosis and necrosis need to be confirmed by further investigation.

Interposition vein cuff and intimal hyperplasia: an experimental study.

OBJECTIVE: There is some evidence to suggest that prosthetic distal bypass graft patency can be improved, and the risk of intimal hyperplasia diminished, by interposing a distal vein cuff. We studied intimal remodeling in an end-to-side distal prosthetic anastomosis constructed with and without a vein cuff. METHODS: Twenty-four prosthetic bypasses were constructed with (N=12) or without (N=12) a distal vein cuff in 12 pigs. At 10 weeks, the 20 anastomoses and adjacent arteries from the surviving 10 pigs were studied by histology, immunohistochemistry and morphometry. RESULTS: Intimal hyperplasia was significantly less on all zones of the arterial floor and all suture zone of arteries anastomosed with a vein cuff than within arteries anastomosed without a vein cuff (0.11 versus 0.34; p=0.001 and 0.35 versus 1.19; p=0.0001, respectively). Intimal hyperplasia was also more prominent within the vein cuff than within the recipient artery, with or without a vein cuff (1.35 versus 0.38; p=0.0001). CONCLUSION: An interposition vein cuff at the distal anastomosis between a prosthesis and an artery alters the distribution of intimal hyperplasia. By acting as an expansion chamber where intimal hyperplasia can develop harmlessly, the vein cuff may protect the arterial anastomosis from stenosis.

Patency and limb salvage after distal prosthetic bypass associated with vein cuff and arteriovenous fistula.

OBJECTIVE: To assess the usefulness of vein cuff with or without arteriovenous fistula interposition as adjuvant techniques for improving patency and limb salvage in patients undergoing femorodistal bypass surgery using prosthetic grafts. METHOD: We undertook a retrospective study of 65 consecutive patients treated over a 5-year period with 67 prosthetic femorodistal bypasses with vein cuff, in whom an arteriovenous fistula was constructed at the distal anastomosis in 35. Patients were followed for a median time period of 23 months. RESULTS: Primary patency rates were 68, 53 and 44% at 1, 2 and 3 years, respectively. The corresponding figures for secondary patency, limb survival and patients' survival were 73, 64 and 58% for 1 year, 78, 76 and 73% for 2 years and 72, 66 and 63% for 3 years. None of the criteria analyzed influenced patency or limb salvage on prosthetic bypasses using adjuvant techniques. No statistical differences were found between patency and limb salvage rates in patients for whom the vein cuff was constructed with or without an arteriovenous fistula. But patients who managed with a supplementary arteriovenous fistula had significantly fewer distal residual arteries in the limb (p=0.001). CONCLUSION: Although results in patients treated with adjunctive techniques differed little from those in patients treated with direct prosthetic bypasses procedures, those who eventually had an adjunctive procedure had inferior runoff. This indicates that an arteriovenous fistula might be a valuable supplement in patients with poor runoff who have distal revascularisation using a prosthetic graft.