High-output cardiac failure due to excessive shunting in a hemodialysis access fistula: an easily overlooked diagnosis.

A dialysis arteriovenous fistula caused life-threatening high-output cardiac failure in a 66-year-old patient. Excessive shunting through the dialysis fistula was demonstrated by invasive measurement of cardiac output, systemic arterial blood pressure, systemic vascular resistance, and oxygen consumption before and after temporary occlusion of the dialysis fistula. Noninvasive echocardiographic evaluation of the influence of fistula compression on cardiac output and noninvasive duplex measurement of the fistula flow also confirmed the diagnosis. Following surgical closure of the fistula, the patient's condition improved, and signs of congestive heart failure subsided. High-output cardiac failure is a rare complication of dialysis arteriovenous fistulas. The diagnosis may remain unrecognized for longer periods. Noninvasive methods for estimation of the hemodynamic importance of a fistula may be of help in the establishment of the proper diagnosis.