Systematic review of intra-operative duplex scanning during renal transplantation

Intra-operative duplex ultrasound scanning in renal transplantation: protocol and service requirements

Intra-operative duplex ultrasound in renal transplantation was first described in 1998 and whilst reported in problematic cases, there are few reports of its routine use and no current published protocols. Since 2013, we have used intra-operative ultrasound in all renal transplants. The formal protocol used since August 2020 is presented as a reference document for other transplant centres. A Canon Aplio 800 ultrasound system with an i22LH8 hockey-stick transducer is used to image the renal cortex and major vessels, and an i8CX1 matrix transducer to image the graft during and after fascial closure. These transducers are fully sterilised with Sterrad and no sheathing of transducers is required. The transplant surgeon scans within the sterile field with the sonographer guiding imaging and adjusting machine settings. Ultrasound findings are discussed between team members including any requirement for interventions. Ultrasound is performed at three stages of the operation: Stage 1: after clamp release identifying issues of graft vascularity including otherwise unrecognised major vessel and anastomotic abnormalities. Stage 2: following ureteric implantation identifying compromised perfusion due to graft rotation or vessel kinking. Stage 3: after fascial closure identifying compromised perfusion due to external compression. Post-operative scanning, including assessment of the collecting system and bladder, is performed routinely on days 1, 3, 7 and 30. The intervention is effective with no early graft losses or peri-operative vascular thromboses. The requirements for service provision are significant including the availability of additional transducers, and sonographers with expertise in intra-operative scanning able to attend after-hours for extended periods.

Early Outcomes in Renal Transplantation With Routine Intraoperative Duplex Ultrasound

BACKGROUND

While intra-operative duplex ultrasound scanning can be readily performed in renal transplantation, the value of this intervention in routine practice is not established.

METHODS

Three hundred thirty-one consecutive single renal transplants in adult recipients underwent intraoperative scanning at implantation. Early graft losses were compared with those recorded in the ANZDATA Registry.

RESULTS

Nine overt vascular abnormalities were corrected prior to scanning. Four further suspected venous outflow restrictions were confirmed by ultrasound and revised. Another 11 major vascular revisions were performed following intraoperative ultrasound consisting of 7 otherwise unsuspected inflow abnormalities, all corrected, and 4 anastomoses redone to reposition the graft. Thirty-two (9.7%) grafts were repositioned under ultrasound guidance to improve cortical perfusion but without vascular revision. One graft with hyperacute rejection was explanted 4 days postimplantation and one graft with primary nonfunction remained well perfused. Two patients died within 90 days, both with functioning grafts. Twenty-three grafts were re-explored within 7 days, including 9 solely for graft hypoperfusion. There were no postoperative arterial thromboses and, at re-exploration, no arterial anastomoses required revision. There were no postoperative venous thromboses, although one venous anastomosis was revised. No grafts were lost within 90 days for surgical or technical reasons compared with 76 (1.0%) of 7603 contemporaneous grafts in the ANZDATA Registry (P = .077 Fisher's exact test, P = .069 χ² test).

CONCLUSIONS

The routine use of intraoperative ultrasound appears to be of benefit by identifying otherwise unrecognized vascular abnormalities, leading to a reduction in early graft losses because of surgical factors.