Biomedical subjects
Publications and source records attributed to Luc Turmel-Rodrigues.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The autogenous arteriovenous fistula has long been proven to be the most durable access for hemodialysis and therefore for any therapy based on plasma exchange. Forearm autogenous fistulas are, however, frequently challenging to create, leading less experienced surgeons to create elbow fistulas or even worse, to place prosthetic grafts. Once the arteriovenous access is constructed, stenoses largely located on the venous side frequently occur, leading to thrombosis if they are not detected and preventively treated. Interventional radiology is now the first line and preferred treatment in the majority of cases of vascular access dysfunction. The overall advantages compared with conventional surgery are its minimal invasiveness, better preservation of the patient's venous reserve, and better outcomes for selected indications such as thrombosed autogenous fistulas. Prophylactic dilation of stenoses greater than 50% associated with clinical abnormalities such as flow-rate reduction is warranted to prolong access patency. Stents are placed only in selected cases with clearly insufficient results of dilation but they must never overlap major side veins and obviate future access creation. Thrombosed fistulas and grafts can be declotted by purely mechanical methods or in combination with a lytic drug. The success rates are over 90% for dilation, in central veins radiologists frequently resort to the use of stents. Long-term results after dilation in the largest series are better in forearm native fistulas compared with grafts. The initial success rates for declotting are better in grafts compared with forearm fistulas but early rethrombosis is frequent in grafts so that primary patency rates can be better for native fistulas from the first month's follow-up.
Articles proving that the majority of thrombosed autogenous fistulae can be recovered by interventional radiology are relatively recent, and the largest series to date have favored mechanical methods including manual catheter-directed aspiration, the Hydrolyzer, Amplatz Thrombectomy device, Arrow-Trerotola device, and the rotating pigtail. Rare contraindications to declotting include infection, fistula immaturity, and large aneurysms. The success rates range from 76% to 100% and compare well with the surgical approach whose effectiveness is not supported by comparable publications. The technical challenges of this outpatient procedure can include difficulties in initial catheterization of the vein or in crossing tight stenosis and actual removal of large thrombi. Although more challenging to declot than grafts, forearm autogenous fistulae are more rewarding. Better long-term patency has been achieved in the largest series to date as long as the underlying stenoses are sufficiently dilated (50% 1-year primary and 80% secondary patency rates). The results reported in the upper arm are less good. The unmasking of stenoses in close to 100% of cases warrants stenosis detection programs similar to those for grafts.
PURPOSE: To review the place of interventional radiology in arteriovenous access for hemodialysis. METHODS: Prophylactic dilation of stenoses greater than 50% associated with clinical abnormalities such as flow-rate reduction is warranted to prolong access patency. Stents are placed only in selected cases with clearly insufficient results of dilation but they must never overlap major side veins and obviate future access creation. Thrombosed fistulae and grafts can be declotted by purely mechanical methods or in combination with a lytic drug. RESULTS: The success rates are over 90% for dilation, with frequent resort to stents in central veins. Long-term results in the largest series are better in forearm native fistulae compared with grafts (best 1-year primary patency: 51% versus 40%). The success rates for declotting are better in grafts compared with forearm fistulae but early rethrombosis is frequent in grafts so that primary patency rates can be better for native fistulae from the first month's follow-up (best 1-year primary patency: 49% versus 26%). CONCLUSION: Radiology achieves results comparable with surgery, with minimal invasiveness and better venous preservation. However, wide variations in the results suggest that the degree of commitment of physicians might be as important as the type of technique used.
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