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Severe iliac artery calcification in patients with end-stage renal disease is a common barrier to listing for kidney transplant. While few surgical solutions to iliac calcification have been reported, improving treatment may thus improve access to transplant care. Here we present two cases of a novel application of remote endarterectomy of the external iliac artery to facilitate listing for renal transplant. Both patients were listed following remote endarterectomy, followed by successful renal transplants using the treated vessels.
As such, the demand for kidney transplantation is also rising, with 78 690 waitlisted patients as of 2019. However, this represents only a fraction of the total population of ESRD patients who may benefit from transplantation.
Patients with severe calcification of the external iliac arteries are frequently not candidates for transplantation. While there are no discrete studies on exclusion for calcification alone, studies assessing trends in pretransplant listing suggest this number may be as high as 20% of the ESRD population.
Though it is certainly true that there remains an organ shortage in the United States, improving treatments for iliac calcification may improve access to transplant.
Few surgical solutions to extensive iliac calcification are reported, including open bypass, orthotopic transplantation to native renal vessels, endarterectomy at the time of transplantation, and iliac artery resection with GoreTex interposition graft.
Unfortunately, these techniques carry significant risks, including infection and organ loss.
Though remote endarterectomy (RE) has been described for iliofemoral occlusive disease and limb ischemia, it has not been reported in the pretransplant setting.
Here, we discuss an initial experience performing RE of the external iliac artery (EIA) in patients with ESRD to facilitate listing for renal transplant. RE may provide a pathway forward for patients denied access to transplantation based on anatomy alone.
2. Methods
Medical records and imaging studies were retrospectively reviewed with approval of the Institutional Review Board of the University of Maryland Medical Center. Two patients received RE in 2021. Indications for treatment included severe circumferential calcification of the EIA precluding listing for transplant. RE was performed using the LeMaitre EndoRE™ Remote Endarterectomy Device. The use of RE devices for both femoral and iliac arteries has been previously described in the literature.
Computerized tomography (CT) was obtained following endarterectomy.
3. Cases
3.1 Case 1
A 57-year-old female with a history of hypertension, type 1 diabetes, and prior simultaneous pancreas-kidney transplant (1995) with subsequent kidney graft failure on hemodialysis was referred for a pre–kidney transplant evaluation. CT scan showed extensive circumferential calcification of the bilateral iliac arteries (Fig. 1A). She was referred to vascular surgery for operative intervention to improve candidacy for transplantation and underwent RE of the right EIA, the target vessel for future renal transplantation. A 9 × 20 mm balloon angioplasty device was used to occlude the right common iliac artery (CIA). Following femoral cutdown, a LeMaitre RE device was used to elevate and remove EIA plaque under fluoroscopy. A large segment of plaque was extracted (Fig. 1B). Follow-up angiogram demonstrated patency. The right femoral arteriotomy site was repaired with a bovine pericardial patch. Postoperative CT scan confirmed patency of the endarterectomized right CIA (Fig. 1C). Shortly thereafter, the patient was activated on the waitlist to accept organ offers.
Fig. 1Case 1. (A) CT scan prior to treatment. (B) Plaque removed during remote endarterectomy. (C) CT scan following right external iliac artery remote endarterectomy. Arrow indicating recanalized artery. (D) Dissection of treated recipient external iliac artery at time of subsequent kidney transplant. (E) Arteriotomy of treated external iliac artery. (F) Renal ultrasound of the transplanted vessel (main renal artery) on postoperative day 1 following deceased donor renal transplant, with triphasic wave forms and no sign of proximal stenosis.
Eleven weeks following RE, she received a cadaveric kidney (DBD, KDPI 36, single artery, vein and ureter). KTx was performed in standard fashion via a right-sided Gibson incision. The remotely endarterectomized right EIA was found to be adherent to adjacent tissues but without signs of damage or fragility and suitable for anastomosis (Fig. 1D). An 11 blade and arteriotomy punch yielded a 6-mm anastomotic target (Fig. 1E). Consistent with endarterectomy, the vessel contained no intima but appeared to be reendothelialized. The kidney perfused well, and transplant ultrasound obtained on the night of surgery indicated patent vasculature and anastomoses (Fig. 1F). Following a brief course of delayed graft function, kidney function stabilized and she remains off hemodialysis. Follow-up time to date is 6 months, with most recent creatinine of 1.11.
3.2 Case 2
A 55-year-old male with a history of hypertension and prior failed KTx (2000) on hemodialysis since 2016 was referred for pre-KTx evaluation. On CT scan he had severe aortoiliac calcification (Fig. 2A) and was referred to combined transplant-vascular evaluation prior to consideration for listing. He underwent RE of the left EIA, the target for future renal transplant. CT scan 1 month postoperatively confirmed patency of the left EIA, with plaque removed and now suitable for use in transplantation (Fig. 2B). He was subsequently reevaluated for kidney transplant and listed.
Fig. 2Case 2. (A) CT prior to remote endarterectomy. (B) CT following left external iliac artery remote endarterectomy. Arrow indicating recanalized artery. (C) Renal ultrasound of the transplanted vessel (main renal artery) on the night of surgery following deceased donor renal transplant, indicating patent vasculature.
Seven months following RE, he received an offer for a cadaveric kidney (DBD, KDPI 65, single artery, vein, ureter). KTx was performed in standard fashion via left-sided Gibson incision. The endarterectomized EIA was free of plaque at the level of anastomosis and the kidney perfused well. Transplant ultrasound obtained on the night of surgery indicated patent vasculature (Fig. 2C). Though he initially experienced slow graft function, kidney function stabilized and he remains off dialysis. Follow-up to date is 3 months posttransplant.
4. Discussion
Extensive vascular calcification is common among ESRD patients on dialysis, thought to be related to chronic systemic inflammation, oxidative stress, and disturbances in mineral metabolism.
As extensive calcification often precludes listing for transplantation, RE may improve chances of listing and access to transplant.
Techniques previously described to address this issue in the pretransplant population have faced several limitations. Open bypass of the EIA is limited by increased intraoperative risk as well as subsequent vascular graft infection.
The risk of infection is a particularly significant consideration in the setting of immunosuppression. Simultaneous open endarterectomy at the time of transplant has also been described; however, this technique is limited in the setting of extensive vascular calcification and has been associated with increased risk of postoperative complications.
Here we describe RE as a technique to address extensive vascular calcification in the pretransplant patient. RE allows for endarterectomy of a long segment of the EIA without retroperitoneal dissection that may complicate access for future renal transplant. By avoiding the use of synthetic graft, the native EIA is left available for use in transplant and reduces the risk of subsequent infection. Done in the pretransplant setting, it reduces the risk of complications seen in endarterectomies done concurrently, and allows for confirmation of revascularization prior to transplantation. Furthermore, this study highlights the broader implications of increasing access to renal transplant in the ESRD population.
However, as this is a novel application for RE, currently we are limited by a sample size of only two cases, with several other patients scheduled to undergo the procedure in the near future. Although this technique has yielded excellent results in our patients, further study is required to confirm these findings in a larger cohort. We also cannot comment on the long-term outcomes of this technique, including future graft function, as our follow-up time to date is limited.
5. Conclusion
Extensive vascular calcification is one reason patients may be denied access to transplantation. RE may offer a pathway to successful listing and subsequent transplantation.
Disclosure
The authors of this manuscript have no conflicts of interest to disclose as described by the American Journal of Transplantation.
Data availability statement
Data sharing is not applicable to this article as no new data were created or analyzed in this study.
Acknowledgments
The authors have no funding sources or personal acknowledgments to disclose.
Appendix A. Supplementary data
The following is/are the supplementary data to this article:
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