혈액투석을 위한 동정맥루

혈액투석을 위한 동정맥루

참고 : J Am Coll Cardiol Intv 2010;3:1–11




Autogenous arteriovenous fistula
  --> surgically formed by directly anastomosing an endogenous artery to an outflow vein






The failure of autogenous arteriovenous fistulas to mature within several months of surgical creation has been attributed to several etiologies, but the presence of an inflow stenosis caused by neointimal hyperplasia at the juxtaanastomotic site is a mechanism amenable to interventional therapy

The late failure of either autogenous arteriovenous fistulas or prosthetic grafts is caused by the appearance of a stenosis within an outflow vein that reduces flow and leads to thrombosis. The underlying mechanism is the marked increase in shear stress in the thin-walled outflow vein, which triggers focal fibromuscular hyperplasia and causes a fibrotic venous lesion to appear.





Signs of Access Failure

Monitoring

The mature fistula or graft should course conspicuously in the subcutaneous tissue and have a prominent thrill and continuous medium-pitched bruit similar to the continuous murmur of a patent ductus arteriosus. Disappearance of the thrill and bruit is diagnostic of hemodialysis-access thrombosis.

Increased post-dialysis bleeding suggests the presence of an outflow stenosis. A prominent pulsation over the access is abnormal and may signify elevated pressure within the access caused by an outflow stenosis. Marked arm edema usually indicates dual venous obstruction in both the cephalic and basilic veins or an isolated occlusion of a central vein related to prior central venous catheter placement in the axillary, subclavian, or brachiocephalic veins or in the superior vena cava.

The inability to insert dialysis needles into a patent but hypoplastic fistula or the finding of a soft bruit and fine thrill over a recently created fistula may indicate the presence of an anastomotic inflow stenosis.



Infection

Signs of infection are indicated by the presence of cellulitis, fluctuance, skin breakdown, or purulent discharge. Uremia may mask fever or leukocystosis. Access infection is a contraindication to interventional treatment because of the resistance of infected thrombus to endovascular therapies and the risk of sepsis.



Surveillance

Hemodynamic surveillance should prompt referral for angiographic evaluationif dynamic venous pressures on hemodialysis exceed 120 mm Hg, fistula flow falls to 500 ml/min, graft flow decreases to 650 ml/min, or access blood flow falls by more than 25%. The observation of rising pressures 340 cm H2O at a constant flow of 200 ml/min may also indicate the presence of an outflow stenosis





Interventional therapy

Contraindications to angiographic management of thrombosed accesses include the presence of a right-to-left intracardiac shunt, pulmonary hypertension, infected access, or surgical revision 30 days before referral.















* Rt. Brachiocephalic vein stenosis 예시


79/F, CC : Arm swelling









끝.
2018. 7. 19 - SJH


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