Building a better kingdom : leadership formation of laity in small United Methodist churches

https://place.asburyseminary.edu/ecommonsatsdissertations/2595/thumbnail.jp

Comparative results of open lower extremity revascularization in nonagenarians

IntroductionThe average lifespan in the United States continues to lengthen. We have observed a similar trend in our patients, with an increased number of nonagenarians presenting for evaluation of vascular disease. This study evaluated outcomes of lower extremity revascularization in patients aged ≥90 years.MethodsThe vascular registry at Albany Medical College was retrospectively reviewed for all lower extremity bypasses performed between 1996 and 2006. We evaluated patient demographics, indications, procedure, patency rates, and complications. Patients were divided into groups based on age ≥90 years (≥90 group) and <90 years (<90 group). Variables were evaluated by χ2 analysis. Outcomes were prepared using life-table methods and compared with log-rank analysis.ResultsDuring the last 10 years, 5443 lower extremity bypasses were performed on patients aged <90 years and 150 on patients aged ≥90 years. The <90 group had significantly more men (61.4% vs 29.3%) and was obviously younger, at 68 years (range 7-89 years) vs 92 years (range, 90-101 years). The <90 group had more comorbidities in terms of diabetes, active tobacco use, and hypercholesterolemia. No significant difference was noted in coronary artery disease or chronic renal insufficiency between the groups. Critical limb ischemia as an indication was significantly higher in the ≥90 group (149 [99%] vs 4472 [82%]; P < .0.5). Strikingly, the primary patency was significantly higher in the ≥90 group at 4 years (77% vs 62%; P < .05). Complication and amputation rates did not differ between the groups. Perioperative (15% vs 3%; P < .05) and 1-year (45% vs 11%; P < .05) mortality rates were significantly higher in the ≥90 group.ConclusionLower extremity bypass for nonagenarians offers acceptable patency and limb salvage but at a significantly higher mortality rate

Evidence of localized, incipient melting during field-assisted sintering of oxide dispersion strengthened, nanocrystalline metals

Oxide-dispersion-strengthened (ODS) nanostructured FeNiZr alloys were produced via high energy mechanical alloying and subsequently consolidated via the field assisted sintering technique (FAST). Processing parameters of temperature, pressure, and dwell time were altered in an effort to achieve full densification and optimize the mechanical performance. Indications of incipient melting were observed via optical and scanning electron microscopy (SEM) at processing temperatures as low as 700 °C. This temperature is less than half of the homologous temperature of the FeNiZr alloy or any of its constituents. This suggests substantially higher temperatures are achieved locally within the powder compact as a result of Joule heating during consolidation. Additional evaluation with X-ray diffraction was performed to identify the implications of this incipient melting on mechanical properties. Please click Additional Files below to see the full abstract

Brachial artery reconstruction for occlusive disease: A 12-year experience

AbstractObjective: Symptomatic arterial disease of the upper extremity is an uncommon problem. In this study, we evaluate our results with brachial artery reconstruction in patients who present with symptomatic atherosclerotic occlusive disease and compare this cohort's demographics with a similar group with lower extremity ischemia. Methods: From 1986 to 1998, all patients presenting for upper extremity revascularization with chronic ischemia were prospectively entered into a vascular registry. Demographics, indications, outcomes, and patency were recorded. Patients presenting with embolus, pseudoaneurysm, or trauma were excluded. The Fisher exact and Student t tests were used to assess significance. Results: Fifty-one (83%) bypass grafts were performed with autogenous conduit and the remainder with polytetrafluoroethylene. Indications included 18 (30%) patients with exertional arm pain, 35 (57%) with rest pain, and 8 (13%) with tissue loss. Twenty-five (45%) patients were male, 8 (14%) had diabetes, and 30 (54%) were smokers. The mean age was 58 years (range, 33-93). The operative mortality rate was 1.8%, and follow-up ranged from 1 to 140 months. Eight occlusions were identified, with six occurring early. Five of these were in women with a smoking history. Only one of the 26 reconstructions that did not cross a joint occluded, whereas bypass grafts that did cross a joint occluded more frequently. No other major complications were recognized. Conclusion: Arm revascularization for ischemia can be performed with reasonable mortality and morbidity rates. These patients may represent a different subgroup of atherosclerotic disease than those with lower extremity involvement: they are more commonly women and smokers and less likely to be diabetic. (J Vasc Surg 2001;33:802-5.

Carotid-carotid crossover bypass: Is it a durable procedure?

AbstractPurpose: Reconstruction of a diseased common carotid artery may necessitate direct repair via aortic artery-based revascularization. However, carotid-carotid artery crossover grafting is an alternative extra-anatomic option that obviates the need for median sternotomy. We analyzed our results with carotid-carotid artery crossover bypass surgery. Methods: Data were analyzed for all patients undergoing carotid-carotid crossover bypass surgery from 1995 to 2000. Data on patient demographics, indications for surgery, perioperative morbidity and mortality, and graft patency were retrieved from a vascular surgery data base and hospital records. Stroke-free survival and graft patency were determined with life table methods. Results: Over 5 years, 24 carotid-carotid artery crossover bypass procedures were performed to treat both symptomatic (n = 19, 79%) and asymptomatic (n = 5, 17%) disease. Nine procedures (38%) were performed in men, 3 (13%) in patients with diabetes, 12 (50%) in active smokers, and 2 in patients with a history of Takayasu arteritis. Patient mean age was 63 years (range, 38-79 years). Twenty-three patients (96%) received polytetrafluoroethylene conduit grafts, and the remaining patients received vein grafts. Ten (42%) patients underwent concomitant endarterectomy. There were no perioperative deaths. One patient (4%) had asymptomatic early occlusion, one had transient neurologic deficit (4%), one (4%) required additional surgery because of bleeding, and one (4%) had a perioperative cerebrovascular accident (stroke). Three (17%) asymptomatic late occlusions were identified at 11, 57, and 64 months, respectively. Mean follow-up was 30 months (range, 1-70 months). Primary patency was 88%, and secondary patency was 92% at 3 years. Stroke-free survival was 94% at 4 years. Conclusion: Carotid-carotid artery crossover bypass surgery is a safe and durable procedure. Its use precludes the need for median sternotomy and provides acceptable stroke-free survival. (J Vasc Surg 2003;37:582-5.

Using environmental tracers to evaluate the preservation of palaeoclimate signals in aquifers of the London Basin, UK

The concept of aquifer basins as palaeoclimate archives has existed for some decades, yet few detailed studies comparing aquifer types have been carried out. To assess the potential of a particular aquifer as an archive, its hydrogeochemical characteristics must be thoroughly investigated, ideally in comparison to an adjacent aquifer which can be shown to substantially preserve its ice-age endowment at depth. The London Basin (UK) presents such an opportunity, containing two main aquifers of contrasting type: the Chalk, a fractured microporous limestone, and the Lower Greensand, a porous sandstone. Despite intensive exploitation of both, evidence for Devensian (late-glacial) water remains at depth, though this differs between aquifer type. To understand the reasons for this, a suite of environmental tracers has been applied. In addition to hydrochemistry, stable isotopes (δ18O, δ2H), carbon isotopes (δ13C-DIC, 14C-DIC) and noble gases (He, Ne, Ar, Kr and Xe), two tracers new to the basin (CFCs and 14C-DOC) have been used. In effect the Lower Greensand appears to be the ‘reference aquifer’, preserving recharge from prior to the Last Glacial Maximum (LGM), while the Chalk contains mixed water, with no remaining trace of the undiluted pre-LGM end member even at depth in remote parts of the confined basin. Whereas both aquifers had in the past given maximum 14C-DIC model ages ≥ 30 kyr (the effective limit of that method), in the present study the use of 14C-DOC has reduced this to 23.4 kyr (Lower Greensand) and 17.2 kyr (Chalk). Similar contrasts in maximum stable isotope depletions (−8.2 ‰ and −7.8 ‰ δ18O) and noble-gas-derived recharge temperature minima (2.6° and 4.1 °C) were also observed. CFCs were found at all Chalk sites, with traces detectable even at 40 km from outcrop, so some climate signal degradation appears inevitable throughout the Chalk aquifer of the basin. A correlation between 14C activity and excess 4He suggests that deep saline water in the Lower Greensand could be ≥ 50 kyr old. The use of 14C-DOC in particular appears to be key to understanding how reliable these individual aquifers are as palaeoarchives

Strategies to improve spinal cord ischemia in endovascular thoracic aortic repair: Outcomes of a prospective cerebrospinal fluid drainage protocol

PurposeAlthough endovascular repair of thoracic aortic aneurysm has been shown to reduce the morbidity and mortality rates, spinal cord ischemia remains a persistent problem. We evaluated our experience with spinal cord protective measures using a standardized cerebrospinal fluid (CSF) drainage protocol in patients undergoing endovascular thoracic aortic repair.MethodsFrom 2004 to 2006, 121 patients underwent elective (n = 52, 43%) and emergent (n = 69, 57%) endovascular thoracic aortic stent graft placement for thoracic aortic aneurysm (TAA) (n = 94, 78%), symptomatic penetrating ulceration (n = 11, 9%), pseudoaneurysms (n = 5, 4%) and traumatic aortic transactions (n = 11, 9%). In 2005, routine use of a CSF drainage protocol was established to minimize the risks of spinal cord ischemia. The CSF was actively drained to maintain pressures <15 mm Hg and the mean arterial blood pressures were maintained at ≥90 mm Hg. Data was prospectively collected in our vascular registry for elective and emergent endovascular thoracic aortic repair and the patients were divided into 2 groups (+CSF drainage protocol, −CSF drainage protocol). A χ2 statistical analysis was performed and significance was assumed for P < .05.ResultsOf the 121 patients with thoracic stent graft placement, the mean age was 72 years, 62 (51%) were male, and 56 (46%) underwent preoperative placement of a CSF drain, while 65 (54%) did not. Both groups had similar comorbidities of coronary artery disease (24 [43%] vs 27 [41%]), hypertension (44 [79%] vs 50 [77%]), chronic obstructive pulmonary disease (18 [32%] vs 22 [34%]), and chronic renal insufficiency (10 [17%] vs 12 [18%]). None of the patients with CSF drainage developed spinal cord ischemia (SCI), and 5 (8%) of the patients without CSF drainage developed SCI within 24 hours of endovascular repair (P< .05). All patients with clinical symptoms of SCI had CSF drain placement and augmentation of systemic blood pressures to ≥90 mm Hg, and 60% (3 of 5 patients) demonstrated marked clinical improvement.ConclusionPerioperative CSF drainage with augmentation of systemic blood pressures may have a beneficial role in reducing the risk of paraplegia in patients undergoing endovascular thoracic aortic stent graft placement. However, selective CSF drainage may offer the same benefit as mandatory drainage