EVAR Technical Tip – Confirmation of Contralateral Limb Gate Cannulation Using a Moulding Balloon☆

Article Outline

• Abstract
• Introduction
• Report
• Discussion
• Conflict of interest/funding
• Copyright

Abstract 

Introduction

Accurate confirmation of cannulation of the shorter contralateral limb gate of an abdominal aortic endograft can be challenging. Catheter angiogram may not exclude all possible errors.

Report

Accurate contralateral cannulation can be confirmed by insertion of a moulding balloon over a stiff wire and gentle inflation of the moulding balloon across the contralateral gate of the main body component.

Discussion

The technique of using a moulding balloon to confirm accurate cannulation of the contralateral gate is a good method of eliminating doubt whilst maintaining a stable wire and catheter position.

Keywords: Abdominal aortic aneurysm, Endovascular aneurysm repair, Cannulation

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Introduction 

Cannulation of the shorter contralateral limb gate of an abdominal aortic endograft can be demanding. Absolute confirmation of accurate cannulation is equally challenging. Successful cannulation is normally confirmed by exchange of the cannulating wire for a catheter followed by an angiogram to demonstrate contrast passing through the endograft into the distal aneurysm. However, catheter malposition may not be fully appreciated on an angiogram.

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Report 

During attempted cannulation of the contralateral limb gate of an endograft the wire can appear to enter the contralateral gate and pass superiorly to the main body of the endograft, but may not actually traverse the endograft. Instead, the wire may pass outside the endograft and exit into the suprarenal aorta between the endograft and the aneurysm neck. Wire exchange for a catheter and angiogram at this point may not alert to the error. Assuming there is not a type I endoleak, contrast will move from the proximal aorta into the endograft, as it would were the catheter in the correct position.

Confirmation of accurate contralateral gate cannulation can be achieved by exchange for a stiff wire, insertion of a moulding balloon over the stiff wire and gentle inflation of the moulding balloon across the contralateral gate of the main body component. A “mushroom” appearance of the moulding balloon across the contralateral gate, extending proximally into the main body of the endograft (Fig. 1, Coda^® Balloon Catheter, Cook Medical with the Endurant™ Abdominal Stent Graft, Medtronic) or distally from the contralateral gate (Fig. 2) will confirm correct wire positioning. Non-mushrooming of the balloon will indicate malposition.

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• Figure 1 

  The “mushroom” appearance of a moulding balloon (Coda^® Balloon Catheter, Cook Medical) across the contralateral gate and extending proximally into the main body of the endograft (Endurant™ Abdominal Stent Graft, Medtronic).

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• Figure 2 

  The “mushroom” appearance of a moulding balloon (Coda^® Balloon Catheter, Cook Medical) across the contralateral gate and extending distally from the contralateral gate (Endurant™ Abdominal Stent Graft, Medtronic).

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Discussion 

The technique of using a moulding balloon to confirm accurate cannulation of the contralateral gate is a good method of eliminating doubt whilst maintaining a stable wire and catheter position. An alternative method, twisting a pigtail catheter inside the stent graft, requires partial withdrawal of the wire. The technique of using a moulding balloon is particularly helpful with short main body components and iliac tortuosity, where multiple exchanges of wires and catheters may result in loss of position. The technique is also of value in fenestrated grafts where a guidewire could bypass the contralateral gate of the distal body component and pass directly into the proximal body component.

Moulding balloons range from 7 to 10 French (F) in size and manufacturers recommend introducer sizes of 12–14F. If a moulding balloon is used selectively rather than routinely, up-sizing the introducer sheath is required. The use of an up-sized introducer sheath on the contralateral side is routine in some endograft types (Endurant™ Abdominal Stent Graft, Medtronic) but not all (Zenith Flex^® Endovascular Stent Graft, Cook Medical). Though local variations exist, the cost of a Coda balloon is £350 (before tax) and the cost of a 12F, 0.038, 13 cm, Check-Flo Performer Introducer^® sheath (Cook Medical) is £60 (before tax). Thus, in some endovascular procedures where sheath upsizing is required, additional cost will be incurred.

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Conflict of interest/funding 

None.