Recirculation: a uremic syndrome complicating the use of prosthetic arteriovenous fistulas for hemodialysis.

Malfunction of prosthetic arteriovenous fistulas is described in two patients, unheralded by abnormalities of arterial flow or venous resistance. In each case, significant graft recirculation due to stenosis of the venous limb caused the insidious onset of uremic symptoms in patients apparently receiving adequate hemodialysis. The uremic syndromes disappeared after correction of the faulty vascular access. Recirculation may be a "silent" cause of prosthetic graft malfunction which is promptly diagnosed by a simple mathematical formula. Routine estimates by a simple mathematical formula. Routine estimates of recirculation should be performed in any chronic hemodialysis patient with relapse of uremic symptoms or suspicious serum chemistries despite regular, uncomplicated hemodialysis. Patients found to have significant recirculation should be considered for angiography and graft replacement or revision.