Press backgrounder Philips VesselNavigator in the repair of abdominal aortic aneurysms VesselNavigator, Philips’ latest image-guidance tool for Vascular Suites and Hybrid OR Suites (operating rooms suitable for both open surgery and minimally-invasive surgery), is a real-time 3D navigation solution that allows interventional radiologists and vascular surgeons to perform a wide range of endovascular procedures. These procedures, which reduce the need for open surgery, typically involve passing a catheter through major arteries or veins in order to position and deploy therapeutic implants such as stents. However, because interventional radiologists and vascular surgeons performing these procedures cannot physically see or touch the blood vessels they are trying to repair, they require sophisticated real-time image guidance tools to assist in catheter guidance and implant placement. VesselNavigator combines real-time X-ray imaging (X-ray fluoroscopy) data with preacquired diagnostic CTA (computed tomography angiography) or MRA (magnetic resonance angiography) images to provide the necessary 3D guidance. Abdominal aortic aneurysm repair Endovascular aneurysm repair (EVAR) for abdominal aortic aneurysms is one commonly performed procedure where VesselNavigator offers benefits. An abdominal aortic aneurysm (AAA) is a ballooning of the abdominal aorta that can rupture without warning (typically being asymptomatic), resulting in massive internal bleeding and death unless patients are operated on quickly. Around 8 out of 10 people with a ruptured aortic aneurysm either die before they reach hospital or don’t survive surgery. AAAs are sufficiently common (occurring in 1.3% to 8.9% of men and 1.0% to 2.2% of women over 60 years of age1) that some countries have recently initiated ultrasound screening programs to identify them. As a result, the number of EVAR procedures being carried out to repair AAAs before they rupture is increasing (CAGR 10%). AAAs were originally repaired via open surgery, during which the patient’s abdomen is opened up and a tubular stent-graft is manually stitched in place to reinforce the affected section of aorta. Although this treatment has a high success rate (93% to 97% of patients achieve a full recovery), the downside is that it imposes significant trauma on the patient, resulting in longer hospitalizations and extended recovery times. Today, an increasing number of AAAs are being treated using EVAR procedures to insert the stent-graft. These minimally-invasive procedures not only impose less trauma on the patient, resulting in faster patient recovery, they also offer a solution for patients who are considered too frail to survive open surgery. Stent-graft placement needs to be performed with precision, especially if the stent has apertures in it to allow blood to flow from the repaired aorta into artery side branches such as those that feed the patient’s kidneys or diaphragm. These ‘fenestrated’ stent-grafts are often custom made to match a patient’s unique anatomy. Placing them in a so-called FEVAR (fenestrated endovascular aneurysm repair) is particularly challenging due to the need to both vertically and rotationally align the apertures in the stent with the appropriate artery side branches. Risk of renal failure Courtesy of Dr. J. van Herwaarden Up until now, vascular surgeons or interventional radiologists performing EVAR or FEVAR procedures typically needed to capture various views of the patient’s abdominal arteries (2D X-ray fluoroscopy images from different angles) during the procedure in order to achieve correct stent placement. However, the radioopaque contrast agent that needs to be injected into the blood to image the arteries is toxic to the kidneys, so one of the risks associated with complex EVAR and FEVAR procedures is a type of acute renal failure called contrastinduced nephropathy. Impaired initial renal function is therefore one of the criteria that often excludes patients from having these procedures. Reducing risk, increasing accuracy Philip’s VesselNavigator software significantly reduces the need for repeated real-time imaging during the procedure, and hence the risk of contrast-induced nephropathy or longterm kidney damage, by fusing pre-operatively acquired CTA or MRA images with a single X-ray fluoroscopy image acquired at the beginning of the procedure. Once vascular surgeons or interventional radiologists have correctly registered these images (typically through the use of ‘landmarks’ in the image, such as the Courtesy of Prof. Dr. Schermerhorn, Boston, USA patient’s pelvis) the 3D information contained in the CTA or MRA images allows them to view the patient’s abdominal vasculature from any angle, without the need to shoot additional X-ray images for that purpose. It is this ability to view the vasculature in 3D that helps to achieve the necessary accuracy in stent placement. Over-exposure to contrast medium used to visualize the arteries with X-ray imaging during the procedure can damage the kidneys. With a growing population of elderly and diabetic people who suffer from poor kidney function, reducing contrast medium requirements significantly benefit the patient population. In clinical studies carried out at the University Hospital Cologne, Germany, and the University Hospital Ghent, Belgium, the use of VesselNavigator has been shown to reduce contrast medium usage by 70%2 and procedure times by 18%3 – leading to safer, more efficient and more cost effective treatment of vascular conditions. VesselNavigator joins Philips’ extensive portfolio of live, 3D image-guided navigation solutions for minimally invasive procedures. This portfolio also includes HeartNavigator and EchoNavigator for structural heart disease repairs, EP Navigator for cardiac electrophysiology interventions, and EmboGuide to support tumor embolization in cancer treatment. 1 Irwin RS and Rippe JM (2008). Irwin and Rippe's Intensive Care Medicine, Lippincott Williams & Wilkins, ISBN: 978-0-7817-9153-3, page 385. 2 Tacher V, et al (2013). Image Guidance for Endovascular Repair of Complex Aortic Aneurysms: Comparison of Two-dimensional and Three-dimensional Angiography and Image Fusion, J Vasc Interv Radiol, 24(11), 1698-1706. 3 Sailer AM, et al (2014). CTA with fluoroscopy image fusion guidance in endovascular complex aortic aneurysm repair, Eur J Vasc Endovasc Surg. 2014 Apr;47(4):349-56.