Vascular and lymphatic complications after renal transplant

Abstract

Renal transplant is a life-saving treatment option for patients with end-stage renal disease. As with any intervention, transplantation is not without potential complications, which include disruption to arterial, venous and lymphatic structures in the region and can involve either native or transplanted anatomy. Management options range from open surgical intervention to endovascular procedures, the latter of which have become increasingly more prevalent due to their minimally invasive nature. Interventional Radiology has a diverse procedural skillset that can be utilized for successful management of post-transplant complications. Treatment modalities include, but are not limited to, embolization, thrombectomy and stent placement. The goal of this article is to explore common vascular and lymphatic complications that occur following renal transplant and review relevant minimally invasive management options. Positive treatment outcomes are essential to ensure graft, and in turn, patient survival.

Keywords: Endovascular management; Interventional radiology; Lymphatic complication; Renal transplant; Vascular complication.

Fig. 1

Sagittal CT angiography demonstrating relevant arterial anatomy of a transplanted kidney. 1- Internal Iliac Artery; 2- External Iliac Artery; 3- Main Renal Transplant Artery; 4– Segmental Renal Transplant Artery; 5 - Common Femoral Artery

Fig. 2

31-year-old female status post RLQ renal transplantation with worsening renal function. Doppler US demonstrated tardus parvus waveforms and decreased resistive index (0.58) in the upper pole segmental renal arteries, suspicious for upstream renal artery stenosis

Fig. 3

67-year-old female status post RLQ renal transplant for ESRD, complicated by donor urine cultures positive for candida albicans. Doppler US demonstrated homogenously decreased parenchymal flow throughout the graft on Power Doppler evaluation (A). An elevated peak systolic velocity of 338 cm/s in the proximal renal artery near the anastomosis was seen on Spectral Doppler evaluation (B). Doppler US of the mid renal artery demonstrated tardus parvus waveforms with a decreased peak systolic velocity of 55 cm/s and decreased resistive index of 0.59 (C). Coronal reformatted CT angiography demonstrated a short segment, severe proximal renal artery stenosis immediately distal to the anastomosis (white arrow) (D). Sagittal reformatted CT angiography revealed a hypoattenuating focus exerting mass effect on the proximal renal artery resulting in severe stenosis (E). Patient was taken to the operating room for further evaluation. A small serous collection (yellow arrow) near the arterial anastomotic site was identified causing the stenosis (white arrow). End-to-side re-anastomosis between the renal transplant artery and external iliac artery was performed

Fig. 4

57-year-old male status post RLQ renal transplant admitted 3 months post-operatively for acute renal failure and volume overload. Spectral Doppler US revealed significantly elevated peak systolic velocities in various segments of the main renal artery (anastomotic site– 712 cm/s) (A). Intrarenal segmental branches on Spectral Doppler US demonstrated tardus parvus waveforms (B). Right external iliac angiogram confirmed stenosis of the proximal transplant renal artery (C). A 6 × 14 mm Express stent (Boston Scientific) was deployed across the stenosis. Post-deployment angiography demonstrated complete resolution of the stenosis with markedly improved blood flow to the transplanted kidney (D)

Fig. 5

57-year-old female with RLQ renal transplant two years prior, found to have elevated peak systolic velocities up to 301 cm/s in the transplanted main renal artery, concerning for renal artery stenosis (not shown). Initial angiogram demonstrated a small region of stenosis in the main renal artery (A). Systolic pressures were obtained distal and proximal to the area of stenosis (distal: 102/45 (66) mmHg; proximal: 107/46 (67) mmHg). The area of stenosis was no longer visualized on repeat angiography (B). Given the lack of pressure gradient and resolution on repeat angiography, the stenosis was believed to be an area of focal vasospasm, and no intervention was performed. The patient was managed medically

Fig. 6

34-year-old female status post RLQ renal transplant complicated by renal artery stenosis seen on US and CT imaging (not shown). Right external iliac angiogram demonstrated three transplant renal arteries (superior– yellow arrow; middle– blue arrow; inferior– green arrow) with hypoperfusion to the mid and lower pole (white arrow), which corresponded to prior CT findings (A). Additional angiography demonstrated tortuosity and stenosis of the transplant middle renal artery proximally (B). Invasive hemodynamic monitoring demonstrated blunted systolic upstrokes (not shown), so angioplasty was performed with a 3.5 mm balloon (C). Subsequent angiography demonstrated improved patency of the middle renal artery (white arrow) and increased perfusion to the mid and lower pole renal transplant (blue arrow) (D)

Fig. 7

​​ Patient with history of LLQ renal transplantation CT angiography demonstrating severe stenosis of the native external iliac artery (not shown). Left external iliac angiogram demonstrated near-complete occlusion of the external iliac artery proximal to origin of the arterial anastomosis (A). Thestenosis was recanalized using a 0.035 Glidewire Advantage and a 5 Fr, 65 cm angled-tapered catheter. Ultimately, a 6 × 18 mm uncovered Express stent (Boston Scientific) was deployed across the region of stenosis (B). Post-procedure angiogram demonstrated no residual stenosis and appropriate flow into the renal artery and left lower extremity (C)

Fig. 8

67-year-old male with combined LLQ renal and heart transplant presenting with acute renal failure. Doppler US (not shown) demonstrated elevated peak systolic velocities within the main renal artery up to 398 cm/s concerning for renal artery stenosis. Pelvic MRA demonstrated abnormal signal in the left external iliac artery near the anastomosis, concerning for dissection (A). Contrast (B, D) and CO2 (C) angiography confirmed a dissection flap within the mid external iliac artery extending above and below the level of the transplant renal artery origin with decreased flow to the renal transplant. A 10 × 40 mm balloon-expandable bare metal stent was deployed just proximal to the anastomotic site. Post-procedure angiography revealed appropriate stent positioning just proximal to the anastomosis with significantly increased flow to the renal transplant (E)

Fig. 9

40-year-old male who presented for RLQ renal transplant biopsy due to concern for rejection. Ultrasound-guided percutaneous biopsy was performed with needle tip identified in the transplant renal cortex (A). Post-biopsy ultrasound (B) demonstrated a color Dopler jet external to the kidney, concerning for active arterial hemorrhage. Main renal artery (C) and upper pole renal artery (D) angiogram demonstrated active extravasation from a right upper pole renal artery branch. A super-selective right upper pole renal artery branch embolization was performed with Nester (Cook) 0.018’’ x 5 cm x 3 mm microcoils with good hemostasis (E)

Fig. 10

16-year-old male status post RLQ renal transplant who presented with hematuria following US-guided percutaneous renal transplant biopsy. Doppler US (A) and CT angiography (not pictured) confirmed an AVF with multiple pseudoaneurysms in the lower pole of the transplanted kidney. Selective transplant renal artery angiography demonstrated dilation of the lower pole segmental artery supplying the AVF with multiple pseudoaneurysms (white arrows) (B). Embolization was performed using 5 mm x 16 cm Azur hydrocoils (Terumo) followed by one vial of Onyx 18 liquid embolic (Medtronic). Post-embolization angiogram demonstrated complete resolution of the AVF and pseudoaneurysms (white arrow) with good opacification of the remaining renal vasculature (C)

Fig. 11

10-year-old female status post RLQ renal transplant who recently underwent US-guided percutaneous biopsy 2 weeks prior due to concern for rejection. Several days following biopsy, the patient developed RLQ pain and anemia, which required takeback to the operating room for evacuation of a perinephric hematoma. Repeat transplant US 10 days following surgery (not shown) demonstrated a suspected renal artery pseudoaneurysm, which was subsequently confirmed on CT angiography (A). Right eternal iliac angiogram confirmed the presence of a pseudoaneurysm arising from the inferior aspect of the transplant renal artery anastomosis, causing focal narrowing of the adjacent external iliac artery and sluggish inflow into the renal transplant artery (B and C). Given these findings, endovascular management was deferred, and the patient returned to the operating room for right external iliac artery reconstruction and transplant renal artery re-anastomosis

Fig. 12

68-year-old male with remote history of RLQ renal transplant and lower extremity DVT requiring IVC filter, subsequently placed on warfarin, who was admitted for multicompartmental intracranial hemorrhage following ATV accident requiring warfarin discontinuation. The patient subsequently developed lower extremity swelling and acute renal failure. CT venogram demonstrated extensive bilateral lower extremity DVT extending into the transplant renal vein (A). Prone venogram performed from right saphenous venous access demonstrated extensive thrombus throughout the external iliac vein with non-opacification of the transplant renal vein (between white arrows) (B). Mechanical thrombectomy was performed using a 20 Fr Inari Flowtriever device (C). Subsequent venogram demonstrated markedly improved venous outflow with some persistent thrombus in the transplant renal vein (D). Aspiration and mechanical thrombectomy were performed in the transplant renal vein through a 5 French Vert catheter with repeat venogram demonstrating near resolution of thrombus with good outflow in the transplant renal vein (E). Renal US the following day demonstrated patent transplant vasculature (F)

Fig. 13

64-year-old female status post RLQ renal transplant admitted 1 week post-operatively with hypotension, hypothermia, acute renal failure and worsening right lower extremity swelling. Noncontrast CT demonstrated chronic occlusion/stenosis of the right common iliac vein, left common iliac vein and IVC with lumbar collaterals bypassing the areas of chronic central venous stenosis (A and B). Catheter venography demonstrated chronically occluded right external vein (upstream of the transplant venous anastomosis) as well as the right common iliac vein and IVC with extensive venous collateralization (C). The right external iliac vein and IVC were successfully recanalized using a small guidewire and Envoy catheter. Pull-back venogram (D) and intravascular US (not shown) demonstrated appropriate positioning within right common iliac vein and IVC. Venoplasty (not shown) was performed using 8 mm x 100 mm and 12 mm x 40 mm Conquest ballons (BD). Ultimately, a 16 × 80 mm Venovo stent (BD) was placed in the IVC as well as a 14 × 100 mm Venovo stent spanning from the right external iliac vein (above the level of the transplant renal vein inflow) to the IVC with 1 cm overlap with the first IVC stent. Completion venography demonstrated markedly improved flow through the right external iliac vein, right common iliac vein and IVC (E). At 1 and 6-month follow-up, patient reported resolution of right lower extremity swelling with GFR > 60 and patent renal and pelvic veins on Doppler and CT venography (not shown)

Fig. 14

40-year-old female status post RLQ renal transplant readmitted two months after transplant with increasing shortness of breath, weight gain and lower extremity DVT. A perinephric fluid collection (white arrow) was identified on admission renal US (A; yellow arrow– renal parenchyma; orange circle– renal hilum). Subsequently, a percutaneous drain was placed using ultrasound-guidance (not shown). Drain output was consistently 400-500 cc per day of thin, light fluid. Drainage fluid labs including creatinine, triglycerides, cell count and culture were unrevealing. Lymphangiogram with lipiodol was performed via a right inguinal lymph node to assess for possible lymphatic leak, which demonstrated contrast pooling into the region of the perinephric collection and drain (B). Lymphatic embolization was performed with approximately 1 cc of 1:7 n-BCA-Lipiodol mixture. Post-embolization imaging demonstrated no further communication (C). Lymphocele sclerotherapy was performed through the percutaneous drain with 7 cc of doxycycline for 90 min following embolization

Fig. 15

72-year-old male status post RLQ renal transplant one month prior with significant output through the surgical drain concerning for lymphatic leak. Admission non-contrast CT revealed a low-density fluid collection (white arrow) in the right hemipelvis inferior to the RLQ renal transplant, suspicious for lymphocele (A). A percutaneous drain was placed under US-guidance into the pelvic collection (white arrow) (B). Lymphangiogram with lipiodol performed via a right inguinal lymph node demonstrated dilated and tortuous lymphatic channels (yellow arrow– lateral lymphatic channel; white arrow– medial lymphatic channel) throughout the right hemipelvis, with lipiodol pooling in the collection near the site of the drain (C). Antegrade embolization with 5:1 mixture of lipiodol: n-BCA glue was then performed, resulting in good embolic opacification of the lymphatic channels at the site of the leak (D)