Combined percutaneous trans-renal and trans-femoral endovascular recanalization and angioplastic reconstruction of a disrupted transplant renal artery stent: A novel salvage technique

Abstract

Renal artery stenosis (RAS) is the most common vascular complication following renal transplantation. Percutaneous endovascular transluminal angioplasty with stenting is the treatment of choice for clinically significant RAS. We present a case describing a novel combined trans-renal parenchyma and trans-femoral approach to repairing a disrupted transplant renal artery stent. Our patient’s allograft RAS was initially managed by standard percutaneous approach, but during follow-up the stent became disrupted and crushed causing partial occlusion of the renal artery. This was manifested by persistently elevated serum creatinine values, lower extremity edema, and four-medication hypertension. After a failed traditional percutaneous trans-femoral attempt, we were able to successfully access the renal arterial system via a combined trans-renal and trans-femoral approach, using an upper-pole artery through the renal parenchyma. This trans-renal approach used a 3 French system, allowing us to get a wire across the stent, which we were previously unable to do. With wire access, we performed a balloon angioplastic reconstruction to restore the stent’s patency, resulting in a reduction in serum creatinine, lower extremity edema, and blood pressure. This technique avoided a potentially difficult re-operative repair without immediate complication and provides a method for vascular access to the renal arterial system in select patients.

Introduction

Renal transplantation is the definitive and preferred treatment for end-stage renal disease (ESRD). Transplant renal artery stenosis (TRAS) is the most common vascular complication following renal transplantation, with an estimated incidence between 1–23%.^{1, 2, 3} This discrepancy in reported incidence is probably the result of variations in monitoring strategies, surgical technique, different thresholds for intervention, and varying lengths of follow-up.⁴ Previous studies have divided TRAS into several subtypes (TRAS-A—anastomotic, TRAS-P—post-anastomotic, and TRAS-B—bend-kink).^{4, 5} Percutaneous transluminal endovascular interventions (EVIs) have emerged as the treatments of choice for each sub-variety, although direct comparisons between approaches are limited.^{6, 7}

EVIs provide a minimally invasive approach to treating TRAS, often obviating the need for surgical re-intervention. Immediate technical success ranges from 90–100%,^{1, 8} and patency rates have been reported at ~60% to > 90% after one year of follow up.^{9, 1, 8, 4} Complications from EVIs include arterial rupture, bleeding, pseudoaneurysm, arterial dissection, thromboembolic events, and stent malfunction/disruption although these are relatively infrequent events (~5–10%).^{6, 10} Here we present a novel intervention employing an endovascular salvage technique to a known complication, stent disruption causing a bend-kink distortion of the stent leading to persistent TRAS.

Case with Results

Our recipient was a 53-year-old African American male with ESRD secondary to a congenital dysplastic kidney (right side), hypertension (HTN), and type II insulin-dependent diabetes. He had been on peritoneal dialysis for four years and his BP was 128/72 on a low-dose ACE-inhibitor at the time of transplant in May of 2014. He received a right kidney deceased donor renal transplant (DDRT) into his left lower quadrant from a 27-year-old male (KDPI 29%). The donor kidney had normal anatomy, the renal vein was lengthened using a dual suture line vena cavaplasty, and an end-to-side anastomosis to the recipient external iliac artery was performed.

Our patient’s operative course was uncomplicated, he began producing urine immediately, and he was discharged on post-operative day four without complication. His initial post-op ultrasound (US) showed patent vessels, a peak anastomotic velocity of 197cm/s, and a resistive index of 0.62. Although he continued to produce normal amounts of urine with stable lab values, his creatinine was slow to normalize. Given his persistently elevated creatinine he underwent a percutaneous biopsy at one month post transplant (Cr 2.38 at the time), which showed no rejection but mild vascular disease. At six weeks post transplant, a duplex US revealed TRAS-A, with a peak anastomotic velocity of 409cm/s that was confirmed by an angiogram which demonstrated a systolic BP gradient of 30mmHg. For this we elected to angioplasty and stent the area of stenosis with a 5×15mm Herculinx stent. The post-intervention SBP gradient was 8mmHg, and he was started on dual antiplatelet therapy with aspirin and Plavix.

Six-months post transplant (January 2015) our patient began developing worsening HTN (MAP of 110 on two medications), though his creatinine remained stably elevated around 2.2mg/dL. An interim biopsy continued to show no rejection, but his US revealed a peak velocity of 657cm/s. We therefore repeated an angiogram that showed his stent had become disrupted and was kinked/crushed at the anastomosis with a portion protruding into the external iliac artery. We tried to access the stent’s lumen from a right- and left-sided groin approach. However, we were only able to get a wire through the stent’s interstices and not through its true lumen (Figure 1). Given our patient’s stable clinical course we decided to watch him clinically and only re-intervene if his HTN or renal function declined.

Figure 1.

A fluoroscopic image from our failed endovascular intervention: via a right groin approach we were only able to attain wire access through the interstices of the stent. Curved arrow = stent; straight arrow = access only through the stent’s interstices.

The decision to re-intervene was made 12 months after our failed EVI as our patient had developed four-medication HTN with increasing lower extremity edema, though his renal function remained stable with a serum creatinine of ~2mg/dL. Given his persistently elevated anastomotic flows (550cm/s), we decided to try an EVI one last time before proceeding to open surgical repair. We held his Plavix for a week pre-intervention since we planned a combined trans-parenchymal and trans-femoral approach.

Given our difficulties in the prior angiogram, we decided to initially access the renal arterial system through an upper-pole artery seen on US, which required going through the kidney’s parenchyma. We did this with a 3 Fr system under US guidance, introducing the needle parallel to the US beam in order to provide better visualization and to avoid traversing other structures (Figures 2a and 2b). Once in, we were able to pass a wire retrograde through the stent’s true lumen and into the femoral artery (Figures 3a and 3b) from where it was snared and pulled out of the femoral sheath providing through and through control (Figure 4). We could then upsize the wire from the femoral access to allow us to adequately angioplasty the crushed stent. However, we were not able to alter the position of the stent and it continued to project into the iliac artery more than we would have liked. It did, however, still cross the anastomosis (Figures 4 and 5). Follow-up measurements revealed an SBP gradient of 12, with an anastomotic velocity of 344cm/s. Our patient experienced no immediate complications and was discharged home. He was recently seen in clinic nearly a month post intervention—he is now on three BP medications, his creatinine has declined to 1.62, and his lower extremity edema has nearly resolved. We hope to continue titrating his BP medications (last measurement 128/83) as allowed.

Figure 2.

a: Black and white ultrasound image showing initial needle access to upper pole artery. White arrow = needle.

b: Color flow image showing initial needle access to upper pole artery. White arrow = needle.

Figure 3.

a: Initial angiogram confirmed trans-parenchymal access to the renal arterial system. Arrow = the catheter is positioned in an upper pole renal artery.

b: We were able to achieve wire access via a percutaneous trans-renal approach through the renal parenchyma. Arrow = wire access via the distal (intra-renal) lumen of the stent.

Figure 4.

We utilized a snare from the trans-femoral access side to obtain through and through control via the stent’s true lumen. Curved arrow = wire across the stent; straight arrow = snare grasping the wire via trans-femoral access.

Figure 5.

We performed an angioplastic reconstruction using 4×2 and 5×2 balloon catheters, dilating them to 5mm to recanalize and restore patency to the stent. Arrow = balloon angioplasty of stent.

Discussion with Technical Methods

EVIs have proven to be an effective and safe option for treating all subtypes of TRAS.⁴ Complications, though infrequent, remain at ~5% in most series.^{10, 11, 12} Here we present a combined percutaneous trans-renal and trans-femoral endovascular approach as a salvage technique to re-canalize a crushed transplant renal artery stent. This utilization of a trans-parenchymal access approach through a transplanted kidney has not been previously reported to our knowledge.

Technical considerations include supine positioning, standard peri-procedural monitoring, and high-quality US combined with fluoroscopic guidance. Percutaneous access to an intrarenal artery using a micropuncture needle set is relatively easy as long as you can visualize the vessel with US. The 3 Fr inner dilator of the micropuncture set, which is smaller than standard renal biopsy needles, allows passage of a 0.018 wire. Potential complications, no different than any renal biopsy, include bleeding, parenchymal damage, and arteriovenous fistula (AVF) formation. As with all biopsies, we have the option of embolizing the tract with gelfoam upon removal of the dilator to further minimize bleeding risk.

A trans-parenchymal approach is commonly used in interventional radiology to perform many procedures involving the liver and kidney and catheters up to 14 Fr can be placed. Intuitively, the larger the catheter used the higher the risk of a bleeding complication. Therefore, keeping catheter size to a 3 or 4 Fr system in this case further minimizes risk. Nevertheless, as with any renal angioplasty/stent procedure, good post-procedural monitoring is important: one must observe for blood loss or renal dysfunction. Admission for one-night observation is reasonable. As with other renal angioplasty or stent procedures, we routinely obtain a baseline duplex the next day before discharge. Office follow up in 1–2 weeks and another duplex in 3 months is our typical protocol unless clinical deterioration occurs.

The trans-renal approach allowed us access to the stent’s true lumen since the distal (intrarenal) end of the stent was not kinked and was evenly apposed to the vessel wall. Once across with a wire we were able to adequately angioplasty the deformed stent via femoral access after snaring the guidewire. We first used a 2mm balloon from the trans-renal side, in order to keep the sheath size to a minimum, and then we completed the angioplasty using a 5mm balloon via the trans-femoral access. We did not flare the ostium because there was a significant amount of stent protruding into the iliac artery. We also did not utilize intra-vascular US since the problem was with the indwelling stent and not an underlying artery, and the stent itself was a good enough marker and could be monitored as per its configuration using fluoroscopic guidance alone. In order to prevent this stent complication from occurring once must use precision technique in stent placement, with accurate placement and the avoidance of unintentional manipulation leading to stent dislocation.

Our trans-renal approach allowed us to save our patient from a potentially difficult open surgical re-operation, and appears to have alleviated much of his TRAS, at least in the short term. In conclusion, EVI remains the initial treatment of choice for TRAS. A percutaneous trans-renal approach is a viable salvage technique to gain access to the transplant renal arterial system, and may be an option for select patients with an accessible vessel on imaging and a renal artery that has flow (i.e. is not completely thrombosed).

Figure 6.

A completion angiogram reveals a properly re-positioned stent with a patent lumen as indicated by the arrow.

Abbreviations

ACE

Angiotensin converting enzyme inhibitor

AVF

Arteriovenous fistula

BP

Blood pressure

BMI

Body-mass index

DDRT

Deceased donor renal transplant

EVI

Endovascular intervention

ESRD

End-stage renal disease

HTN

hypertension

KDPI

Kidney donor profile index

MAP

Mean arterial pressure

TRAS

Transplant renal artery stenosis

US

Ultrasound