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.
[Show abstract] [Hide abstract]
ABSTRACT: Background: We have developed a novel method of measuring spinal cord-evoked potentials with stimulation and recording at the intercostal nerves (transintercostal-evoked spinal cord potential: Tic-ESCP). The purpose of this study was to examine the feasibility and accuracy of Tic-ESCP during thoracic aortic surgery. Methods: In addition to the conventional electrodes (cranial and intrathecal), stimulating and recording electrodes were placed on the intercostal nerves that were located at a cephalad and caudal level relative to the aneurysm after the pleura on the intercostal nerves was opened. Specially designed hook-type electrodes were anchored to the nerves and surroundings atraumatically and fixed on the pleura. The conventional transcranial motor-evoked potential (Tc-MEP) and Tic-ESCP were recorded simultaneously. Eight patients were examined in this study. Results: In all patients, Tic-ESCP could be clearly recorded with biphasic waveforms consisting of first a positive wave and a subsequent negative wave. In all 8 patients, the waveform of Tc-MEP and Tic-ESCP changed during aortic reconstruction. In 2 cases, the waveform of Tc-MEP and Tic-ESCP decreased below 50% of baseline during aortic clamping and the intercostal arteries were reconstructed with no resultant spinal cord injury. In 1 case with a shaggy aorta, Tc-MEP and Tic-ESCP had different values and each evoked potential could have reflected that regional spinal cord infarction and paraplegia had occurred. Conclusions: Tic-ESCP was clinically feasible and changes were compatible with the conventional Tc-MEP. The Tic-ESCP waveforms were simple and appeared to be specific to the spinal cord within the target range, in contrast to the other evoked potentials which are multimorphic and reflect the amplitudes at the brain and multiple levels of the spinal cord.Annals of Vascular Surgery 05/2014; 28(7). DOI:10.1016/j.avsg.2014.04.008 · 1.03 Impact Factor
[Show abstract] [Hide abstract]
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; 36. DOI:10.1016/j.compchemeng.2011.07.007 · 2.45 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: Objectives To evaluate how often newly developed risk prediction models undergo external validation and how well they perform in such validations. Study Design and Setting We reviewed derivation studies of newly proposed risk models and their subsequent external validations. Study characteristics, outcome(s), and models' discriminatory performance [area under the curve, (AUC)] in derivation and validation studies were extracted. We estimated the probability of having a validation, change in discriminatory performance with more stringent external validation by overlapping or different authors compared to the derivation estimates. Results We evaluated 127 new prediction models. Of those, for 32 models (25%), at least an external validation study was identified; in 22 models (17%), the validation had been done by entirely different authors. The probability of having an external validation by different authors within 5 years was 16%. AUC estimates significantly decreased during external validation vs. the derivation study [median AUC change: −0.05 (P < 0.001) overall; −0.04 (P = 0.009) for validation by overlapping authors; −0.05 (P < 0.001) for validation by different authors]. On external validation, AUC decreased by at least 0.03 in 19 models and never increased by at least 0.03 (P < 0.001). Conclusion External independent validation of predictive models in different studies is uncommon. Predictive performance may worsen substantially on external validation.Journal of Clinical Epidemiology 10/2014; DOI:10.1016/j.jclinepi.2014.09.007 · 5.48 Impact Factor