The rare complication of renal biopsy - simultaneous formation of pseudoaneurysm and arteriovenous fistula in kidney transplant

Renal biopsy (RB) is the gold standard for diagnosing causes of kidney transplant (KT) dysfunction. One of the rarest biopsy-related complications is the simultaneous formation of pseudoaneurysm (PA) and arteriovenous fistula (AVF) of KT. The first line diagnostics in such cases is comprehensive allograft ultrasonography (US). The final diagnosis is being established by the results of contrast-enhanced multispiral computed tomography (CE-MCT). A 54-year-old man with end-stage kidney disease secondary to chronic glomerulonephritis was admitted for the start of maintenance hemodialysis. He had received repeated cadaveric KT in 1996 and 2011. The routine RB was performed in 2018, the chronic transplant glomerulopathy was verified. Comprehensive allograft US was performed in the course of hospitalization. B-mode: anechoic ovoid lesion similar to simple cyst and two vessels connected to it are visualized at the border of the midpole region with the lower pole of the allograft (fig. 1a). The size of the lesion is 15×18×14 mm, there are signs of weak pulsation. Color Doppler demonstrated significant depletion of vascular pattern. A mosaic pattern with a speckling of perivascular soft tissue caused by tissue vibration was observed in the lesion projection (fig. 1b). Pulsative Doppler: low-resistance high-velocity spectrogram with turbulent flow in feeding artery (fig. 1c) and arterialized blood flow presumably in draining vein. The data obtained corresponded to the combination PA and AVF. CE-MCT with post-processing image processing was performed: MIP (Maximum Intensity Projection) - (fig. 2a) and VR (Volume Rendering) are presented in fig. 2b (front view) and fig. 2c (left and rear view). The subsegmental branches (large caliber 4-4,5 mm) of the KT lower pole are spirally crossed and form on the top of the intersection of the aneurism with irregular ovoid shape and size 16×19×15 mm. The draining branch forms the shunt (arrows) with renal vein (RV) (fig. 2c). RV and external iliac vein (let V, fig. 2c) are contrasting in the arterial phase, external iliac artery - let A. So, the diagnosis of simultaneous formation of PA and AVF was confirmed by CE-MCKT data. Taking into account the complete loss of the function, the transplantectomy was recommended. The authors declare no conflict of interest. Informed consent for publication of patient's information and images was obtained from our patient.

kidney transplant, renal biopsy, pseudoaneurysm, arteriovenous fistula comprehensive ultrasonography, contrast-enhanced multispiral computed tomography