Morphologic assessment of ePTFE graft wall damage following hemodialysis needle punctures

Abstract

Repeated needle trauma to grafts used for chronic hemodialysis may result in loss of graft integrity and aneurysmal formation. The gross and scanning electron microscope observations of the virgin expanded polytetrafluoroethylene graft (ePTFE) material following repeated needle punctures are presented. Understanding how the normal structure of the ePTFE graft can be affected, particularly by larger diameter needles, underlines the effect and importance of needle puncture technique. In assuming that aneurysm related to needle punctures is the only evolutive complication of the vascular access, this analysis showed that the half life of an ePTFE prosthesis which was 6 mm in diameter and 25 cm in length was reached after about 1512 punctures using the 1.8-mm diameter hemodialysis needle, 1111 punctures with the 2.1-mm diameter needle or 784 punctures with the 2.5-mm diameter needle.

Vascular changes at the puncture segments of arteriovenous fistula for hemodialysis access

“…In an arteriovenous graft, this mechanism has been shown to be involved in the aneurysmal dilation. 11,20,21 The hemodynamic stresses could also play some roles in vascular dilatation at the puncture segments. 3,4 In addition to constant exposure to the increased flow resulting from the shunting flow through the arteriovenous anastomosis, the arterial and venous puncture segments exposed to abrupt hemodynamic stresses changes during hemodialysis.…”

Principles of treating enlarging pseudoaneurysm in a dialysis arteriovenous graft

“…A pseudoaneurysm develops from eventual breakdown of the wall of an AVG . Presence of outflow stenosis may indirectly instigate the breakdown of the graft material.…”

“…The resulting high intra‐graft pressure, combined with trauma from extrinsic repeated cannulation during dialysis, leads to eventual loss of graft integrity. Repeated punctures with sharp dialysis needles at same sites can further lead to graft wall disruption …”

“…1 A pseudoaneurysm develops from eventual breakdown of the wall of an AVG. 5,6 Presence of outflow stenosis may indirectly instigate the breakdown of the graft material. With high relative blood flows within a dialysis access, the presence of downstream lesions can induce high pressures within an AVG.…”

“…Repeated punctures with sharp dialysis needles at same sites can further lead to graft wall disruption. 6 Outflow evaluation is essential in the management of pseudoaneurysm. Adequate treatment of any outflow lesions will reduce intra-graft pressures and thus limit pseudoaneurysm expansion.…”