Thoracic endovascular aortic repair (TEVAR) for acute blunt thoracic aortic injury has good early and mid-term results.
Single-center retrospective 7-year review from January 2001 to December 2008.
Urban tertiary care hospital.
Twenty-four consecutive patients with acute blunt thoracic aortic injury treated with TEVAR.
Procedure-related mortality, stroke, or paraplegia; injury severity score; and complications.
Among the 24 treated patients (mean age, 41 years; range, 20-71 years), the mean injury severity score was 43 (range, 25-66). Thoracic endovascular aortic repair was successful in treating the aortic injury in all patients and there were no instances of procedure-related death, stroke, or paraplegia. Access to the aorta was obtained through an open femoral/iliac approach (n = 7) or an entirely percutaneous groin approach (n = 17). Systemic heparin was not used in 84% of cases. Two access complications (8%) occurred, requiring an iliofemoral bypass in one patient and a thrombectomy in another. One patient required secondary intervention for device collapse, which was treated successfully with repeat endografting. There have been no delayed device failures or complications among the entire cohort at mid-term follow-up.
Thoracic endovascular aortic repair, via a percutaneous groin approach and without systemic anticoagulation, for blunt thoracic aortic injury can be performed safely with low periprocedural mortality and morbidity.
"Unlike other diseases, endovascular repair for BTAI has a relatively short procedural time; therefore, it can be successfully performed with a low-dose of heparin. Garcia-Toca et al.  reported that 84% of endovascular repair patients (20/24) did not undergo heparinization, and only 1 patient developed a thrombotic complication. Thus, whether to use heparin and its optimal dosage should be based upon each patient's risk of bleeding and thromboembolism. "
[Show abstract][Hide abstract] ABSTRACT: Conventional open repair is a suboptimal therapy for blunt traumatic aortic injury (BTAI) due to the high postoperative mortality and morbidity rates. Recent advances in the thoracic endovascular repair technique may improve outcomes so that it becomes an attractive therapeutic option.
From August 2003 to March 2012, 21 patients (mean age, 45.81 years) with BTAI were admitted to our institution. Of these, 18 cases (open repair in 11 patients and endovascular repair in 7 patients) were retrospectively reviewed and the early perioperative results of the two groups were compared.
Although not statistically significant, there was a trend toward the reduction of mortality in the endovascular repair group (18.2% vs. 0%). There were no cases of paraplegia or endoleak. Statistically significant reductions in heparin dosage, blood loss, and transfusion amounts during the operations and in procedure duration were observed.
Compared with open repair, endovascular repair can be performed with favorable mortality and morbidity rates. However, relatively younger patients who have acute aortic arch angulation and a small aortic diameter may be a therapeutic challenge. Improvements in graft design, delivery sheaths, and graft durability are the cornerstone of successful endovascular repair.
Korean Journal of Thoracic and Cardiovascular Surgery 12/2012; 45(6):390-5. DOI:10.5090/kjtcs.2012.45.6.390
[Show abstract][Hide abstract] ABSTRACT: Conventional vertical power MOSFETs are limited at high voltages (>500V) by the appreciable resistance of their epitaxial drain region. In a new MOS-gate controlled device called a COMFET (or an IGR), this limitation is overcome by modulating the conductivity of the resistive drain region, thereby reducing the on-resistance of the device by a factor of at least 10. However, the device previously described is slow in turn-off, having a fall time in the range 8 to 40 µs. The purpose of our present work has been to reduce the fall time significantly and to increase the latching current level of the COMFET, while retaining its desirable features. By modification of the epitaxial structure and addition of recombination centers, we have achieved fall times as low as 0.1 µs and latching currents as high as 50 A, while retaining on-resistance values < 0.2 ohms for a 0.09 cm<sup>2</sup>chip area. The techniques used for the introduction of recombination centers include electron, gamma-ray, and neutron irradiation, as well as heavy metal doping. For a series of COMFETs (with forward blocking voltage capabilities of 400-600V), the fall time can be reduced by more than one order of magnitude with a penalty of less than a 20% increase in on-resistance.
Electron Devices Meeting, 1983 International; 02/1983
[Show abstract][Hide abstract] ABSTRACT: The authors report a pseudomorphic semiconductor-insulator-semiconductor field-effect transistor (PM-SISFET) that uses a thin layer of undoped GaInAs instead of GaAs as the channel-forming layer. The device consists of an undoped AlGaAs barrier layer, a heavily doped n-type GaAs gate, and an upper GaInAs contact layer. With this structure, the device has a naturally negative threshold voltage. The structures were grown by molecular beam epitaxy. The devices were fabricated using, as for conventional GaAs SISFETs, self-aligned ion implantation and rapid thermal annealing (RTA). High-resolution photoluminescence spectra at 4.2 K for both the as-grown layer and after RTA have a FWHM (full width at half-maximum) of 3.1 MeV for a 120-Å-thick GaInAs channel layer with an In content of about 12%. These measurements indicate that no structural degradation of the strained layer occurred during annealing. To compare performance, the authors also grew and processed conventional GaAs/AlGaAs/n<sup>+</sup>-GaAs SISFETs. At 300 K, the 1-μm-gate-length devices showed transconductances and drain currents in excess of 270 mS/mm and 250 mA/mm, respectively, for PM-SISFETs compared to 240 mS/mm and 200 mA/mm, respectively, for similar conventional SISFETs
High Speed Semiconductor Devices and Circuits, 1989. Proceedings., IEEE/Cornell Conference on Advanced Concepts in; 09/1989
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