Repositioning of a Malaligned Aortic Stent-Graft

Letters to the Editor

Repositioning of a Malaligned Aortic Stent-Graft From: Alexander C. Maclennan, FRCR, MRCP* Lindsay S. Machan, MD* Peter D. Fry, MD, FRCS(I), FRCS(C)t Department of Radiology* and Vascular Surgery? Vancouver Hospital & Health Sciences Center, UBC Pavilions 2211 Wesbrook Mall Vancouver, BC V6T 2B5

Editor: We describe a technique for repositioning an unsatisfactorily deployed aortic stent-graft. A 73-year-old man with a 6-cm-diameter infrarenal aortic aneurysm was unfit for standard operative aneurysm repair. Repair was indicated because of the aneurysm size and otherwise unexplained recurrent abdominal pain of 1 years' duration. The aneurysm, assessed with aortography and contrast material-enhanced helical computed tomography (CT), measured 7.0-cm-long and 6.0-cm-wide, with a 2.0-cm-long by 2.2-cm-wide proximal neck and a 1.5-cmlong by 2.2-cm-wide distal neck. The inferior mesenteric artery was occluded, and the iliac arteries were not involved. A Talent straight endoluminal prosthesis (World Medical Manufacturing, Sunrise, Fla) was ordered to fit the aneurysm. After administration of general anesthesia in the angiography suite, a right common femoral arteriotomy was ~erformedand an 18-F introducer sheath was inserted into the aorta. The prosthesis was advanced through the introducer sheath, with a 0.018-inch Radiofocus glide wire M (Terumo, Tokyo, Japan). After angiographic localization, the occlusion balloon was inflated with CO, and the proximal stent and graft were deployed below the renal arteries. However, the body of the graft and connecting bar curved during deployment such that the distal stent deployed with the lumen of the graft directly applied to the aortic wall. A tip-deflecting wire (Cook, Bloomington, Ind), introduced by a 7-F sheath a t the left groin, could dislodge the stent, but it would slip off the stent and the stent would return to its original orientation. A 2.5-cm Goose Neck Amplatz snare (Microvena, White Bear Lake, Minn) could not encircle the entire lower end of the stent because it was embedded against the atheromatous aortic wall. The stent would also not move if traction was placed on individual tines by the snare. A second left groin puncture was performed and the wire and snare were introduced simultaneously. The tipdeflecting wire was used to dislodge and hold the stent from the aortic wall. One of the tines of the stent was then constricted by the snare, and traction was applied to reposition the stent in a horizontal position (Figure). A final angiogram showed a satisfactory position of the stent-graft with minimal perigraft leak. The patient was

Figure. The tip-deflecting wire dislodges the graft-covered stent tines from the aortic wall (arrowhead). The loop snare encircles and constricts a tine, allowing repositioning of the stent.

discharged the following day and has had no further abdominal pain since prosthesis insertion. A CT scan 6 weeks later showed no residual perigraft leak. This was the first patient to receive the Talent endoluminal prosthesis in North America. The Talent endoluminal prosthesis consists of a proximal and distal zig zag nitinol spring assembly with a straight full length nitinol connecting bar embedded in either polyester or polytetrafluoroethylene fabric. The fabric is sewn onto the zigzag spring so that the edge of the prosthesis is serrated rather than smooth. The device is available in straight or bifurcated shapes and is available in any 2-mm-increment diameter (8-30 mm) and any l-mmincrement length (5-20 cm). The prosthesis is constrained between a Teflon inner sheath and a balloon catheter, which are inserted as a unit through an 18-F introducer sheath. The device is deployed by withdrawing the Teflon sheath over the balloon catheter. The balloon catheter has both a proximal occlusion balloon for occluding suprarenal aortic blood flow and a tamping balloon for seating the stents and unravelling the graft. We believe that two problems contributed to the poor seating of the distal stent. First, the lumen of the introducing balloon would only accept guide wires of up to a 0.018-inch diameter. The lack of support from the 0.018-

152

Journal of Vascular and Interventional Radiology

January-February 1997

inch guide wire allowed the stent to release in an improper orientation. The introducing balloon now will accept guide wires of 0.038-inch diameter. Second, the prosthesis was deployed with the connecting bar a t the outer radius of the aneurysm, which may have also encouraged the distal stent to curve. In the future, we will use a stiff 0.038-inch guide wire and deploy tube grafts with the connecting bar to the inner radius of the aneurysm. The use of loop snare and hook-shaped catheters or tip-deflecting wires is well described for foreign body retrieval (1).Fortunately, the serrated edge of the Talent stent-graft made i t easy to snare and reposition without traumatizing the prosthesis. Reference 1. Foreign body retrieval. In: Gerlock JR Jr, Mirfakhree M,

eds. Essentials of diagnostic and interventional angiographic techniques. Philadelphia, PA: Saunders, 1985; 35-37.

Successful Treatment of a Bleeding Renal Tumor with Ethanol From: Lindsay S. Machan, MD* Alexander C. Maclennan FRCR, MRCP* Mark Nigro, MD? Departments of Radiology* and Urology? Vancouver Hospital & Health Sciences Center, UBC Pavilions 2211 Wesbrook Mall Vancouver, BC V6T 2B5 Editor: We report the successful control of severe hematuria from a renal tumor using locally delivered ethanol. A frail 85-year-old man with chronic renal impairment developed hematuria and recurrent, debilitating clot colic. Creatinine level was 192 P ~ o V L(normal range, 80-120 kmoVL), and blood urea nitrogen (BUN) level was 12.6 mmoVL (normal range, 2.5-6.8 mmol/L). A computed tomography scan showed a noncalcified, lowattenuation mass within the upper-pole collecting system. Cystoscopy and retrograde pyelography showed a craggy mass filling and amputating the right upperpole calyx. The presumptive diagnosis of bleeding transitional cell carcinoma was made. Unfortunately, the patient was not fit for surgical nephrectomy because of frailty and the likelihood of becoming dialysis dependent. On the basis of the Tc99m diethylenetriaminepentaacetic acid (DTPA) renal scan, the glomerular filtration rate was estimated a t 25 mL/min, split equally between both kidneys. He was initially treated with topical Thiotepa (Lederle, Markham, Ont), instilled via a retrograde ureteral catheter, but developed repeated bouts of ureteral colic. The patient agreed to undergo local ablation of the tumor with ethanol. Under general anesthesia, a 5-F,

Figure. With the patient prone, the Chiba needle is positioned within the mass before the ethanol is injected. The occlusion balloon is still inflated. 8.5-mm balloon occlusion catheter (Medi-tech/Boston Scientific, Watertown, MA) was wedged into the infundibulum of the upper-pole calyx, over a guide wire previously inserted under cystoscopic guidance. The volume of contrast material needed to fill the occluded calyx was measured a t 3 mL. This was aspirated and 3 mL of 100% ethyl alcohol (Sabex, Boucherville, Que) was injected through the catheter to bathe the tumor. The alcohol was fully aspirated after 5 minutes, and an additional 3-mL aliquot of alcohol was instilled for 5 minutes. Two passes were then made percutaneously into the tumor mass with a 21-gauge Chiba needle and, on each occasion, 1 mL of ethyl alcohol was injected into the tumor (Figure). Mild hematuria persisted for 6 days after the procedure, but there was no deterioration in renal function. There was no further ureteral colic until the patient died 6 months later. The therapeutic challenge, in this patient, was to control bleeding without further compromising renal function. Percutaneous injection of alcohol is a proven treatment for hepatocellular carcinoma (1)and parathyroid adenomas (2). Intraarterial alcohol has been used to perform chemical nephrectomies either for renal cell carcinomas (3) or nonfunctioning hydronephrosis (4). The latter treatment was combined with the pelvicalyceal instillation of alcohol to shrink the nonfunctioning hydronephrotic kidneys. Intracavity alcohol has also been used for the sclerosis of hepatic and renal cysts. The effect of alcohol is due to cellular dehydration and coagulation necrosis with subsequent vascular thrombosis and fibrosis (1).Percutaneous ethanol ablation offered the potential to cause focal tumor necrosis while sparing surrounding renal tissue. There also seemed a possibility of thrombosing a focal point of vascularity that might have been the cause of the brisk bleeding episodes. The treatment was successful in abolishing the colic while preserving renal function. We recommend adding