Patients with aneurysms with short or angulated necks and those with involvement of the renal, visceral, and hypogastric arteries may not be candidates for endovascular treatment using infrarenal stent graft. Fenestrated stent grafts with reinforced fenestrations permit the incorporation of the visceral and renal arteries into the endovascular repair enabling an adequate proximal sealing zone. These devices require a 6-week to 8-week period for customization and are not currently commercially available in the United States. Modified fenestrated stent grafts may have a future role in the compassionate treatment of selected high-risk patients with complex aneurysms who otherwise would not have access to a manufactured fenestrated stent graft, or for those in need of urgent or emergent repair because of impending or contained ruptured, rapidly expanding or excessively large aneurysm. The authors have used modified fenestrated stent grafts selectively in patients with large aortoiliac, juxtarenal, pararenal, or thoracoabdominal aortic aneurysms. In this article, the authors summarize the principles applied for device design and procedure planning, as well as the technique for device modification and implantation.
Background: Postoperative ARDS has mortality exceeding 45% in certain surgical populations. Statins have been shown to possess immunomodulatory and anti-inflammatory effects. The objective of this study was to determine if preoperative statin therapy is associated with a reduced frequency of postoperative ARDS in targeted surgical populations at increased risk of developing ARDS. Methods: A retrospective cohort evaluation of the association between preoperative statin therapy and postoperative ARDS was performed. The study population included consecutive patients undergoing elective high-risk thoracic and aortic vascular surgery. The association between preoperative statins and postoperative ARDS was first assessed with univariate analyses. To control for confounding factors a propensity-adjusted multivariate logistic regression analysis was then performed. Results: Out of 1845 surgical patients, 722 were receiving perioperative statin therapy. 120 patients developed ARDS. The frequency of ARDS among those who were receiving statin therapy versus those who were not was 7.2% vs. 6.1% (OR = 1.20, 95% CI = 0.83 – 1.75; p = 0.33). After adjusting for the propensity to receive statin therapy as well as other confounding variables, statins were not associated with a reduced frequency of ARDS (OR 1.02, 95% CI = 0.65 – 1.62; p = 0.93). Conclusions: In patients undergoing high-risk thoracic and aortic vascular surgery, preoperative statin therapy was not associated with a reduction in early postoperative ARDS. These results do not support the use of statins as an ARDS preventative measure in patients undergoing high-risk surgery.
Branched endoprostheses for endovascular repair of pararenal and thoracoabdominal aortic aneurysms are undergoing evaluation in prospective clinical trials. Duplex ultrasound has been a cornerstone of surveillance for vascular reconstructions. This paper describes the development and deployment of a standardized duplex imaging protocol to evaluate individuals who have undergone endovascular repair of their thoracoabdominal aortic aneurysm. Ultrasound imaging is performed after an 8 to 12 hour fast to minimize the presence of bowel gas and allow for optimal imaging of abdominal vascular structures. Doppler measurements of peak systolic and end diastolic velocity are made at specific arterial segments in the aorta and the celiac, superior mesenteric, and renal arteries. Resistive indices are also recorded in the segmental and arcuate arteries of both kidneys. Pulsed-wave Doppler is used to record spectral Doppler data and color Doppler is used to image all arterial segments and ensure proper placement of the Doppler sample volume and ensure correct angle of interrogation. Implementation of a standardized duplex ultrasound imaging protocol can be used to image and follow individuals who have received the Thoracoabdominal Branch Endoprosthesis (TAMBE) device and branched endovascular aneurysm repair (BEVAR). Ultrasound may provide complementary findings and may add information to the computed tomography angiography imaging for following these individuals.
From its inception in 1993, the Cook Zenith endovascular abdominal aortic aneurysm (AAA) graft presented a more complex but very controlled deployment mechanism. It has undergone several modifications since its first implantation and now can accommodate aortic neck diameters up to 32 mm and iliac artery diameters up to 20 mm. In addition, it possesses an uncovered, barbed suprarenal stent to allow for transrenal fixation of the device and has been loaded into low-profile, flexible, hydrophilic sheaths, which facilitate device delivery. The major advantages of the Zenith endograft include suprarenal fixation, a flexible delivery system, and the ability to treat a broad range of aortic and iliac artery diameters. This review will discuss the evolution of the Cook Zenith abdominal aortic aneurysm endovascular graft and will focus on the history and development of the device, device description and characteristics, and a thorough literature review focusing on the US Pivotal Study 4-year results, device-specific outcomes, factors associated with poor results, transrenal fixation and renal function, endoleaks, migration, aneurysm sac shrinkage, secondary procedures, and device cost.
