Maximum inflation diameter
32, 40 mm
20, 27, 33, 40 mm
65, 110 cm
65, 100 cm
A 12–14 F sheath, 45–60 cm, can be utilized to achieve aortic occlusion. For open repair, this will be adequate. When utilizing EVAR with a bifurcated device, the CODA balloon is positioned on the side of the planned contralateral limb. Imaging can be performed through the central wire lumen or through the side arm of the sheath (Fig. 12.1a). Once the endograft main body is deployed, the AOB can then be placed on the ipsilateral side while gate cannulation and limb extensions are performed (Fig. 12.1b–d). Most patients will tolerate temporary deflation of the AOB for endograft deployment at the proximal seal zone followed by placement of the AOB within the main body of the endograft. Placing an 18–20 F sheath allows room for double access next to the occlusion balloon and placement of an imaging catheter near the renal vessels. Iliac occlusive disease can be detrimental if the sheath is unable to be passed through the iliac vessels. Once the endograft main body is deployed, the AOB can then be placed on the ipsilateral side while gate cannulation and limb extensions are performed. When Endologix AFX is utilized (Endologix, CA) for EVAR, a 18–20 F contralateral sheath allows room to place the snare alongside the balloon shaft. This eliminates the need to deflate the occlusion balloon if the patient is unstable. The surgeon’s choice of sheath will be based on the balloon chosen and their planned approach for RAAA repair.
Intraoperative placement aortic occlusion balloon during EVAR for hemodynamically unstable RAAA. Images provided by Dr. Benjamin W. Starnes, University of Washington. (a) The AOB is positioned at the level of the 12th rib. The renal arteries are marked below the AOB. (b) The stent graft is positioned with the AOB inflated. Partial AOB deflation allows positioning of the stent graft below the renal arteries. (c) The stent graft is deployed with the AOB inflated. The ipsilateral limb is completed, achieving seal within the common iliac artery. A second aortic occlusion balloon is then positioned within the stent graft seal zone from the ipsilateral side. (d) The contralateral limb is completed, and the completion angiogram demonstrates RAAA exclusion without endoleak
Balloon Positioning and Inflation
Under fluoroscopic guidance, the balloon is directed to the thoracic aorta. The balloon should be positioned above the aortic aneurysm between the pararenal and retrocardiac aorta. The quality of aorta should also be appreciated on preoperative axial imaging to avoid areas with thrombus, plaque, and calcification. Placing the balloon in the thoracic aorta at the level of the 12th vertebral body will allow working room for imaging below the balloon and it will facilitate delivery of the main endograft from the ipsilateral side. Even with this position, the balloon may require partial deflation to allow the nose cone on the endograft to pass. A 60 cc syringe with contrast is used to inflate the balloon under direct visualization. The volume of contrast required to achieve aortic apposition is marked. During test inflation, it is also important to support the back of the balloon with the sheath to avoid balloon displacement down the aorta (Fig. 12.2). When this occurs, the balloon is not fully opposed to the aortic wall, and downward pressure causes the balloon to drag down the aortic wall. This can result in aortic plaque embolization. Once test inflation and positioning is complete, the balloon is deflated. The position of the balloon is marked on the table with a sterile marker, the sheath is also marked or sutured in place, and the volume of contrast used to create aortic occlusion is recorded. Balloon inflation is then reserved for hemodynamic support. At this step, the surgeon may proceed with open or endovascular repair.
Aortic occlusion balloon position for proximal control. (a) The support sheath is positioned beneath the occlusion balloon in the paravisceral segment. In this example, the balloon is situated in parallel aorta but is occluding the renal and visceral arteries. (b) The occlusion balloon is wedged at the infrarenal aortic neck. This position will require directed forward pressure on the sheath to ensure occlusion. This will allow perfusion of the viscera and both kidneys. (c) This illustrates occlusion balloon deployment from the left brachial or axillary approach
Open RAAA Repair
With open surgery, proximal aortic occlusion may be required to support anesthesia induction and laparotomy. Aortic occlusion provides afterload needed to support cerebral and coronary perfusion; this will reduce the amount of cardiac pressors and fluid administered for induction. In addition, optimizing coronary perfusion will improve cardiac output. The surgeon primary goal is to place an infrarenal clamp at the infrarenal location. Once infrarenal control and distal control are obtained, the balloon can be deflated and then pull back through the infrarenal neck. At this stage, the surgeon can digitally control the aorta and feel the balloon and wire pass through this point. Aortic clamps can then be positioned for open repair.
Endovascular Aneurysm Repair for RAAA
When general anesthesia is chosen, the aortic occlusion balloon provides the same advantages described for open repair. If the balloon is not required, the stent graft can be deployed in a standard fashion. If the balloon is required to support hemodynamics, the main body of a bifurcated device can be deployed below the balloon in an infrarenal location. If the patient can tolerate balloon deflation, pulling the balloon down into the aneurysm sac just prior to proximal stent graft deployment avoids trapping the balloon beyond the stent graft and proximal stents. If the proximal AOB must remain inflated due to patient condition, it is my preference to ensure the contralateral sheath is well above the stent graft seal zone. This allows the AOB to be re-sheathed in the proximal aorta, and then the sheath and balloon can be pulled caudally between the stent graft and the aortic wall. The goal is to avoid stent graft displacement. Once the bifurcated system has been deployed, the AOB can be placed from the ipsilateral approach while the contralateral limbs are deployed.