Endovascular treatment for thoracoabdominal aneurysms: outcomes and results.
ABSTRACT Endovascular treatment of thoracoabdominal aortic aneurysms (TAAA) in combination with selective open surgical revascularization may be an alternative to conventional surgical repair. We analyzed our patient outcomes after elective and emergent endovascular TAAA repair.
Mortality and outcome data from 21 consecutive patients treated with endovascular TAAA repair between 2000 and 2006 were reviewed. An integrated neuroprotective approach was used on all patients. Mortality risk estimates for open surgery (OS) were calculated using the published risk assessment models and compared to our outcomes.
Of the 21 patients, 9 had acute presentation: acute pain (9), rupture (6), and malperfusion (1). The celiac axis was overstented in 15. Nine hybrid open surgical procedures were performed: visceral/renal arteries (5), infrarenal aorta (3) and complete arch revascularization (1). Eleven patients had previous aortic surgery. Thirty-day mortality rate was 4.8% (1/21, predicted OS value 8.3%), 1-, 2- and 3-year survival was 80%. One hospital death occurred due to ischemic colitis after inferior mesenteric artery overstenting. No patient with acute presentation died during the initial hospital admission. There was no paraplegia (predicted OS rate 11.46%) and one event of delayed temporary paraparesis 3 weeks after hospital discharge corrected with raising the blood pressure. Other neurologic complications included one minor left pontine stroke with complete resolution, postoperative confusion (1) and saphenous nerve injury (1). No new late endoleaks occurred after initial complete aneurysm exclusion. Five patients underwent early (<30 days) and four patients underwent late endovascular reinterventions for persistent endoleak. An additional reintervention included percutaneous stenting of a superior mesenteric artery stenosis. Actual freedom from late reintervention was 81%, and 76% at 1-, 2 and 3-year follow-up. Late major adverse events included one stent infection leading to multi-organ failure and death.
Endovascular treatment of thoracoabdominal aneurysms with selective visceral and renal revascularization is associated with low mortality and can only be effectively performed by a surgeon. High-risk patients and those with acute presentation appear to benefit most from this therapy. Early results up to three years of this therapy are encouraging, but further follow up to validate long-term results is required.
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ABSTRACT: This study explores the effect of different types of non-isothermal mixing on water-using network's utility consumption target, and some non-isothermal mixing rules are deduced, which can be used to estimate if utility will increase, decrease or remain unchanged after non-isothermal mixing. The energy penalty caused by heterogeneous mixing can be eliminated by decreasing the temperature approach between hot and cold streams through indirect heat transfer before mixing, so that the mixing can remain as a means of direct heat transfer when synthesizing heat-integrated water networks. Based on the non-isothermal mixing rules, one can make full use of direct heat transfer by mixing to obtain a simpler network structure and avoid the possibility of an energy penalty caused by improper non-isothermal mixing.Computers & Chemical Engineering 01/2012; · 2.45 Impact Factor
Conference Paper: Analysis and synthesis of general planar interferometer arrays[Show abstract] [Hide abstract]
ABSTRACT: This paper presents the first theory for general planar radio interferometers. Previously published results for the three antenna linear inteferometer are completely generalized to interferometers consisting of any number of antennas in arbitrary planar configurations. For any interferometer in this much wider class, the maximum likelihood bearing estimation algorithm can be derived, and its performance calculated using the results derived here. The antenna phase centers are viewed as generating a two dimensional lattice in the array plane. This lattice is the dual or reciprocal of the lattice in the direction cosine plane consisting of all direction cosine pairs which represent angles which are ambiguous with the array boresight. It is shown that the likelihood function for the unknown integer portions of the phase measurements can be reduced to an integer quadratic form which represents a generalized distance squared between an (N-2) dimensional projection of the phase measurement and the points of a lattice in phase space. The ambiguity resolution procedure is thus reduced to determining the closest lattice point to a given point.Acoustics, Speech, and Signal Processing, IEEE International Conference on ICASSP '83.; 05/1983
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ABSTRACT: Conventional open surgical repair, endovascular treatment, and the hybrid technique constitute the three treatment options for patients with type IV thoracoabdominal aortic aneurysms (TAAAs). Treatment is advocated to prevent rupture but yields significant risk for spinal cord ischemia, cardiovascular, and renal and respiratory complications, including death. Refinements in open surgical techniques and branched endovascular graft repair together with the development of hybrid techniques have been applied to the treatment of type IV-TAAAs to decrease the risk of these complications. However, much of the evidence of the argument is circumstantial. Large experiences are limited to a few centers worldwide with inherent disparity between patient groups and several limitations to the construction of a prospective randomized trial. This controversial subject is now open to discussion, and our debaters have been given the challenge to clarify the evidence to justify their preferred option for repair of type IV-TAAAs.Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 07/2011; 54(1):258-67. · 2.98 Impact Factor