Transradial Delivery of a Renal Snorkel During Complex Endovascular Aortic Aneurysm Repair

Introduction

Percutaneous transradial arterial access is a well-described technique, primarily in the context of coronary angiography and intervention. ^1,2 Although perhaps commonly performed in practice, data regarding the treatment of noncoronary vascular disease are mostly limited to small series and case reports of peripheral interventions. ^3,4 There is even less regarding the treatment of visceral arteries ⁵ and aortic aneurysmal disease. ⁶ Access from the upper extremity is useful in a variety of noncoronary procedures and is absolutely required for the delivery of snorkel and chimney grafts for complex endovascular aortic aneurysm repair (EVAR). ⁷ Traditionally, this has been done via brachial or axillary artery access, using either an open or percutaneous technique. ⁸ Radial artery access offers some potential advantages over these options, including patient comfort and earlier ambulation. ⁹ Moreover, the risk of brachial sheath hematoma and median nerve palsy is obviated, and there is less potential for hand ischemia due to the collateral flow from the ulnar artery and palmar arch. ¹⁰ Here we present a case of transradial delivery of a snorkel stent during endovascular aneurysm repair in a patient with a short infrarenal neck.

Case Report

A 71-year-old man with a known, asymptomatic abdominal aortic aneurysm presented to the clinic for annual duplex surveillance. Over the course of 1 year, his aneurysm had grown in maximal diameter from 4.5 to 5.5 cm, which was later confirmed on computed tomographic (CT) angiogram. His past medical history was significant for coronary artery disease with prior myocardial infarction and 2-vessel coronary artery bypass grafting, hypertension, and atrial fibrillation, for which he takes warfarin. Given the increase in size, he was recommended for endovascular repair. However, there were some anatomic challenges including a short infrarenal neck of 10.0 mm and an accessory left renal artery (Figure 1). The right renal artery and superior mesenteric arteries arose at the same level approximately 6 mm above the main left renal artery, and the decision was made to perform a left renal snorkel graft to augment the proximal seal zone and land the main device just below the more proximal right renal artery. The small left accessory renal artery was to be sacrificed. To establish antegrade access for delivery of the snorkel graft, a right transradial approach was chosen as the right radial artery was significantly larger than the left. A Barbeau test ¹¹ was performed by placing a pulse oximeter on the index finger and manually occluding both the radial and ulnar arteries until the waveform was lost. Sequential release of each vessel demonstrated return of an appropriate tracing on pulse oximetry, confirming adequate collateral flow from the ulnar artery and palmar arch. Right radial access was then obtained under local anesthesia using a 4F micropuncture technique and exchanged for a 6F Glidesheath Slender (Terumo Medical, Somerset, New Jersey). A cocktail of 200 µg nitroglycerin, 2.5 mg verapamil, and 3000 Units unfractionated heparin was instilled in the artery to prevent vasospasm. The descending aorta was accessed using an angled Glidewire (Terumo Medical) and vertebral catheter (Cook Medical, Bloomington, Indiana) and a 110 cm 6F Flexor Shuttle sheath (Cook Medical) was advanced to the visceral aortic segment to allow for cannulation of the renal artery and angiography through the sheath. The main left renal artery was selected and cannulated and the sheath advanced into the ostium. Bilateral percutaneous femoral access was established, and a Medtronic Endurant main body device (Medtronic, Fridley, Minnesota) was advanced into place. The left renal snorkel was completed with a 6 × 22 mm iCast stent (Atrium Medical), and the remainder of the stent graft deployed (Figure 2). The iliac limbs were also completed with iCast stents due to a narrow aortic bifurcation. Through the radial sheath, subtraction angiography and selective mesenteric and renal cannulation were performed to ensure patency of the left renal snorkel as well as the right renal artery and superior mesenteric artery. An excellent angiographic result was achieved with no endoleaks and filling of the left renal artery (Figure 3). Hemostasis was achieved upon sheath withdrawal from the radial puncture site with use of the transradial band and radial compression device (Terumo Medical). The patient recovered without incident and was discharged home on postoperative day 1. There were no access-related complications, and radial artery patency was confirmed by the presence of a palpable pulse distal to the access site with occlusion of the ulnar artery. At 1 year follow-up, the aneurysm sac had decreased to 4.1 cm, and there was no evidence of endoleak, with good flow through the renal snorkel stent.

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Figure 1.

Three-dimensional rendering of aortic aneurysm. The 3D reconstructions of the aneurysm were created using iNtuition software (TeraRecon, Foster City, California). Panel A demonstrates an overall view of the aneurysm, while panel B shows a magnified view of the aneurysm neck and visceral segment. Panel C is a centerline view demonstrating the neck length and relative positions of the renal arteries and superior mesenteric artery (SMA).

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Figure 2.

Deployment of left renal snorkel and aortic stent graft main body. A 6F sheath and 6 mm iCast stent (Atrium Medical, Hudson, New Hampshire) in the renal artery are denoted by the white arrow, which were delivered via the right radial artery. The main body of the aortic graft is indicated by the black arrow.

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Figure 3.

Completion angiogram. Flush aortography via pigtail catheter demonstrates filling of the stent graft and left renal snorkel, with no endoleak.

Discussion

This report describes a case of a short neck infrarenal aneurysm treated with an adjunctive left renal snorkel to increase the proximal seal zone, with the snorkel stent delivered via a transradial approach. Although the repair is somewhat straightforward with regard to deployment of the components into the aorta and left renal artery, we aim to highlight the transradial access and its utility in delivering the snorkel. The safety profile of transradial access is favorable, with less access site complications than a transfemoral approach in several large, randomized trials of coronary interventions. ^12,13 The transradial technique offers potential benefits over brachial access as well, specifically with regard to patient satisfaction and decreased complications. ^9,10 Overall, radial artery complications occur infrequently and include arterial occlusion (2%-18%), pseudoaneurysm formation (<0.1%), and hemorrhage (<1%). ¹⁰ The vast majority are asymptomatic and can be managed nonoperatively. The most feared complication of hand ischemia is extremely rare and can be prevented by proper preoperative evaluation and case selection.

As an added advantage, hemostasis is easily achieved with the use of a compressive band, which frees the operator from holding pressure for extensive amounts of time. This may be of particular relevance to patients with bleeding diatheses, since the band can be left on for extended periods of time without compromising blood flow to the hand. The risk of brachial sheath hematoma is also eliminated. Transradial access does present its own unique challenges, though. The artery may not be large enough to accommodate the appropriately sized sheaths for the intervention being attempted or may have other anatomic limitations, such as loops or significant tortuosity. ¹⁴ The radial artery is also prone to vasospasm, which can cause significant patient discomfort and may preclude sheath passage. Finally, patient habitus may play a role, as catheters and sheaths may not reach the target vessels in taller individuals.

There are limited reports of transradial access for visceral stenting, ⁵ as most practitioners feel more comfortable with either percutaneous or open brachial arterial access. This holds true for upper extremity access during complex aortic aneurysm repair, as well. As discussed above, the perception is likely that the radial artery is either too small to accommodate the appropriately sized sheath, or that the distance to the visceral segment is too big. However, in our experience, provided the radial artery is at least 2 to 3 mm in diameter, relatively straight, and not heavily calcified sheaths up to 6F can be passed from the distal radial artery near the wrist into the central vasculature and aorta in the majority of patients. This allows 6 mm iCast and 6 mm 0. 018″ Viabahn (W.L. Gore & Associates, Flagstaff, Arizona) covered stents, as well as a variety of self-expanding nitinol stents, to be delivered to the renal or mesenteric arteries. Indeed, taller patients should be approached on a case-by-case basis and only treated via the radial artery if appropriately long sheaths and devices are available. Transradial access should also be avoided in patients without sufficient collateral flow to the hand, those with a current arteriovenous fistula or need for dialysis access, or those with small, diseased arteries. Although in this case it was not possible, we generally prefer left-sided access to prevent crossing the head vessels and to minimize wire–catheter manipulation within the aortic arch.

Conclusions

This case illustrates the feasibility of delivering stents to the mesenteric and renal arteries during EVAR. The technique may well be useful to the interventional practitioner in a variety of additional contexts, given the ability to pass 6F sheaths into the aorta and visceral arteries.