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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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: This paper extends existing results on a technique for gain-scheduled, L 2 -gain control of linear parametervarying (LPV) systems with bounded rates of variation. Specifically, it introduces the use of both memoryless and dynamic (i.e., filtered) parameter measurements when the parameters' accelerations are bounded. Information from the filtered parameter signal can be used to reduce the conservatism of LPV controllers when the parameter variations are slow relative to their worstcase bounds; under such circumstances, the closed-loop performance is closer to that of H1 -optimal point designs. The synthesis results are illustrated by a simulation example. 1 Introduction Much recent attention has been paid to the induced-L 2 norm control of linear parameter-varying (LPV) systems [2, 12]: finite-dimensional linear systems whose state-space data depend on one or more time-varying parameters that are measurable in real-time. These systems are of special interest in gain-scheduled control ...
- Methods in Enzymology 02/2004; 377:344-53. DOI:10.1016/S0076-6879(03)77021-9 · 2.09 Impact Factor