Key words : Allograft thrombosis, Kidney transplantation, Renal vein complications, Vein thrombosis

Introduction
Renal graft vein thrombosis is a formidable complication of kidney transplant. It has been shown to occur in 0.2% to 4.0% of cases and often leads to graft removal.¹ Renal vein thrombosis can be caused by a twisted vein, anastomosis stenosis, hypercoagulation, and ascending thrombosis of the deep veins of the lower extremities. It is diagnosed with Doppler ultrasonography. With anastomosis revision and thrombectomy, the kidney transplant may no longer be viable.² If vein thrombosis occurs intraoperatively, the kidney becomes edematous and cyanotic, and a blood clot can be palpated in the renal vein.

Delayed renal vein thrombosis can also be detected with Doppler ultrasonography. A blood clot can be visualized in the lumen of the vein, and there is poor blood flow in the graft. Thrombolytic therapy may be effective, but angiographic interventions or revision of the anastomosis with thrombectomy may most likely be required.³ Renal allograft thrombosis that affects either the renal artery or the veins is a well-known phenomenon in clinical practice. This complication of kidney transplant surgery is more common in the early posttransplant period and is usually associated with acute rejection mediated by antibodies. Renal vein thrombosis seems to be more common in pediatric than in adult kidney transplant recipients and also seems to have some relation to the duration of peritoneal dialysis before transplant.^4-7

Case Report
A 13-year-old boy presented for transplant with a diagnosis of chronic kidney disease, which was detected in 2017. According to the recommendations of the nephrologist, the patient regularly received outpatient treatment at his place of residence. In 2018, the patient was recommended to undergo programmed hemodialysis with the prospect of kidney transplant. Because of patient refusal, a proactive kidney transplant was recommended. The donor was a 30-year-old cousin from the mother’s side of the patient. HLA compatibility showed matches of HLA-A, HLA-B, and HLA-DR (1 match each), with 10% cross-match.

The patient underwent heterotopic kidney transplant in the right iliac region with the imposition of an end-to-side anastomosis between the kidney artery and the external iliac artery and between the renal vein and an external iliac vein. Uretero-vesical anastomosis was performed in accordance with the standard Lich-Gregoire procedure with double J stenting. A small amount of urine was observed intraoperatively. After surgery, the patient’s hourly diuresis did not exceed 50 mL/h. Graft Doppler ultrasonography showed a reversible blood flow of the graft vessels with high vascular resistance index (RI) of 1.0. We suspected that the patient had venous anastomosis thrombosis, and he was urgently taken to the operating room for revision.

When the external iliac vein was opened below the anastomosis, thrombosis of the external iliac vein occurred with spread from the graft to the vein, completely covering the lumen of the vein. Thrombectomy was performed with reperfusion of the transplanted kidney with Custodial solution through the arterial opening. Next, the external iliac vein and the arterial opening were sutured. After blood flow started, the size, consistency, and color of the kidney returned to normal.

A graft Doppler ultrasonography performed intraop-eratively showed satisfactory blood flow with RI of 0.8. After the operation, diuresis of up to 150 mL/h was noted. The recipient received standard 3-component immunosuppressive therapy. In the postoperative period, 2 hemodialysis sessions were performed in the first 2 days. On the first postoperative day, the daily diuresis was 650 mL, but this gradually increased to 4200 mL on day 8 postsurgery. Creatinine levels decreased from 0.69 to 0.3 mmol/L on day 8 after surgery. There was moderate proteinuria of 1.32 g/L on day 2 and 0.099 g/L on day 7 postsurgery. On day 12 postsurgery, graft Doppler ultrasonography showed smooth contours of the kidney, with dimensions of 12.7 × 6.3 cm. The thickness of the renal parenchyma was 1.7 to 1.9 cm, the pyramidal pattern was not pronounced, and the cup and pelvis system and pelvis were not expanded. Blood flow volume in the arcuate arteries was up to 18.5 cm/s with RI of 0.60. In segmental arteries, blood flow volume was up to 43.9 cm/s with RI of 0.79; on the anastomosis, blood flow volume was up to 157.0 cm/s with RI of 0.87.

Discussion
Graft thrombosis occurs in 0.9% of patients within 1 month after transplant and accounts for 17% of cases of early (within 30 days after transplant) graft insufficiency.⁸ Our patient had a vein graft thrombosis in the first hours after kidney transplant. The most common causes of renal artery thrombosis are antibody-mediated rejection, hypercoagulation syndrome, technical problems associated with graft extraction, and perfusion. A small size graft, displacement, and twisting or bending of the renal artery can also lead to graft thrombosis.⁹ In our patient, an intraoperative venotomy of the external iliac vein was performed below the graft anastomosis, where there was a thrombosis of the external iliac vein with a spread to the graft vein, completely closing the vein lumen. Inflection and torsion were not detected.

With regard to the donor, there may be increased risk of thrombosis when the right kidney is donated; unlike the left, the use of the right kidney is a risk factor for early vascular thrombosis posttransplant.¹⁰ It was further proposed that preventive anticoagulant or antiaggregation platelet therapy should be administered for cases of implantation of the right donor kidney.¹⁰ In our patient, the donor’s left kidney was selected due to the presence of 1 renal vein and artery.

We detected thrombosis of the graft vein in the first hours posttransplant and timely performed reperfusion of the graft Custodial solution through the arterial opening. In addition, we did not have to perform vascular reanastomosis of the graft and achieved complete elimination of thrombotic masses, which contributed to the restoration of graft function. The external iliac vein and arterial opening were tightly sutured. Doppler ultrasonography of the graft can allow identification of signs of thrombosis of the graft vein. With early diagnosis and timely intervention, graft function can be preserved and restored.

References:

1. Lerman M, Mulloy M, Gooden C, Khan S, Khalil A, Patel L, Zhou XJ. Post transplant renal vein thrombosis, with successful thrombectomy and review of the literature. Int J Surg Case Rep. 2019;61:291-293. doi:10.1016/j.ijscr.2019.07.066
   CrossRef - PubMed
   
2. Prokopenko E. Features of the management of the early period after kidney transplantation, complications, and their prevention. “IX Interregional Scientific and Practical Conference of the Russian Dialysis Society in the Volga Federal District: Modern Nephrology,” Perm, Russia, October 7-8, 2016.
   CrossRef - PubMed
   
3. Russian Public Organization of Transplantologists. Russian Transplant Society. National Clinical Guidelines; 2013.
   CrossRef - PubMed
   
4. Budruddin M, Salmi I, Shilpa R. Renal allograft thrombosis in the early post transplant period. Open J Nephrol. 2013;3(3):148-151. doi:10.4236/ojneph.2013.33027
   CrossRef - PubMed
   
5. Gang S, Rajapurkar M. Vascular complications following renal transplantation. JNRT. 2009;2(1):122-132.
   CrossRef - PubMed
   
6. Giustacchini P, Pisanti F, Citterio F, De Gaetano AM, Castagneto M, Nanni G. Renal vein thrombosis after renal transplantation: an important cause of graft loss. Transplant Proc. 2002;34(6):2126-2127. doi:10.1016/s0041-1345(02)02876-2
   CrossRef - PubMed
   
7. First MR, Mendoza N, Maryniak RK, Weiss MA. Membranous glomerulopathy following kidney transplantation. Association with renal vein thrombosis in two of nine cases. Transplantation. 1984;38(6):603-607.
   CrossRef - PubMed
   
8. Bertolatus J. Etiology of renal artery thrombosis in renal transplantation. Medscape Transplant. 2000;1(1). https://www.medscape.com/viewarticle/414133
   CrossRef - PubMed
   
9. Carlesen E, Prydz H. Enhancement of procoagulant activity in stimulated mononuclear blood cells and monocytes by cyclosporine. Transplantation. 1987;43(4):543-548. doi:10.1097/00007890-198704000-00018
   CrossRef - PubMed
   
10. Amézquita Y, Méndez C, Fernández A, et al. Risk factors for early renal graft thrombosis: a case-controlled study in grafts from the same donor. Transplant Proc. 2008;40(9):2891-2893. doi:10.1016/j.transproceed.2008.09.014
    CrossRef - PubMed