AVF Occlusion Unveils True Hemodynamics: When the Shunt Matters.

BACKGROUND

High-flow hemodialysis arteriovenous fistulas (AVFs) can augment measured cardiac output and confound transplant hemodynamic assessment.

CASE SUMMARY: A 58-year-old man with end-stage heart failure and end-stage renal disease awaiting simultaneous heart-kidney transplantation had recurrent presyncope, volume intolerance, and ventricular ectopy despite preserved cardiac output on previous right heart catheterization with AVF occlusion using a blood pressure cuff. Repeat catheterization with duplex-confirmed manual AVF occlusion reduced AVF flow from approximately 2.8 L/min to <300 mL/min, Fick cardiac index from 2.7 to 1.6 L/min/m2, pulmonary artery oxygen saturation from 65% to 49%, and cardiac power output from 0.78 to 0.58 W.

DISCUSSION: Duplex-confirmed AVF occlusion demonstrated that baseline cardiac output and pulmonary vascular indices were shunt-dependent, unmasking low-output physiology not appreciated with subjective occlusion.

TAKE-HOME MESSAGE: Hemodynamics may be misleading unless AVF occlusion is complete and verified during right heart catheterization.