Early experience with renal autotransplant for renal artery stenosis in a 6-year-old patient with neurofibromatosis type 1: a case report

Abstract

Background: Renal artery stenosis due to neurofibromatosis type 1 is a known important source of secondary renovascular hypertension in pediatric patients. There are no guidelines on the management of renal artery stenosis in children, and the utility of stents and bypass grafting is limited given small patient size. Renal autotransplant to treat renal artery stenosis in a small pediatric patient may be a viable alternative for treatment and spare the need for nephrectomy.

Case presentation: In this article, we present a case of renal autotransplant in a 6-year-old, 15.8 kg Nepali patient with neurofibromatosis type 1 with refractory hypertension and high-grade stenosis of the proximal right main renal artery. The patient underwent balloon angioplasty, which failed to dilate the stenosis. He later developed hypertensive urgency and required admission to the pediatric intensive care unit. The patient was not a candidate for repeat angioplasty given the length of the stenotic segment and its tortuosity. Blood pressure was unable to be controlled on multiple antihypertensive agents and the patient eventually developed hypertensive urgency. Therefore, a renal autotransplant of the right kidney was performed after multidisciplinary evaluation. The right renal artery ostium had significant hypertrophied intima involving 50% of its circumference. The kidney was procured in the same fashion as a living kidney donor nephrectomy. The kidney was mobilized in situ, and heparin was administered. The renal artery and renal vein were divided with surgical staplers. The kidney was removed from the patient and moved to the back table. On the back table, the organ was flushed with cold organ preservation solution and vessels inspected. The diseased portion of the right renal artery was resected to the location of no gross intimal thickening. It was judged that there was adequate length of the healthy artery remaining to allow safe reimplantation. The renal artery and vein were reimplanted to the abdominal aorta and inferior vena cava, respectively. The patient tolerated the surgery well, and 2 years postoperatively, he only requires one antihypertensive medication.

Conclusion: Nephrectomy may be favored over renal autotransplant in small pediatric patients due to technical difficulties associated with autotransplant. We demonstrate significant clinical improvement in blood pressure control in a 15.8 kg, 6-year-old pediatric patient after renal autotransplant.

Keywords: Case report; Neurofibromatosis; Pediatric; Renal artery stenosis; Renal autotransplant; Renovascular hypertension.

Fig. 1

Representative (A) sagittal and (B) coronal image from computed tomography angiography of the abdomen. The red arrow demonstrates high-grade stenosis in the proximal right renal artery

Fig. 2

Renal arteriogram. Conventional subtracted angiogram image (A) demonstrating stenosis (red arrows) at the origin of the right renal artery. Subsequent balloon dilation of the lesion (B) with a 4.5 mm diameter balloon shows incomplete dilation of the lesion despite application of maximum rated balloon pressure

Fig. 3

Intraoperative photo of autotransplanted kidney after reperfusion. Intraoperative image of the right kidney re-transplanted after ex vivo excision of stenotic segment of the proximal right renal artery. The blue asterisk highlights the right renal vein re-anastomosed to the inferior vena cava. The red asterisk indicates the right renal artery re-anastomosed to the aorta. The yellow asterisk demonstrates the ureteroneocystostomy

Fig. 4

Postoperative hypertension management and de-escalation of therapy. Postoperative timeline of blood pressure measurements and de-escalation of anti-hypertensives until day of discharge on postoperative day 13