The relationship between dialysis graft pressure and stenosis.

RATIONALE AND OBJECTIVES. Pressure measurements during dialysis have been used to screen for venous outlet stenosis, but the relationship between the degree of stenosis and pressure has not been defined. METHODS. To determine this relationship, failing or failed dialysis grafts (n = 34) were studied with angiography and pressure measurements from the segment of the graft near the arterial anastomosis. RESULTS. By linear regression, the relationship between the highest grade stenosis in or central to the graft and pressure was as follows: percent stenosis = 55 systolic graft pressure/systolic blood pressure + 13 (r = 0.75). CONCLUSIONS. There is a positive correlation between the severity of stenosis and graft pressure, confirming the use of this measurement in screening for stenosis. It is hypothesized that this relationship is the result of progressive elimination of the normal pressure drop between the artery and arterial limb of the graft as the degree of stenosis increases.