Management and outcome of chronic atherosclerotic infrarenal aortic occlusion

Abstract Purpose: To evaluate the management and outcome of chronic atherosclerotic infrarenal aortic occlusion (IRAO), a review of 48 patients who were treated for angiographically documented IRAO between January 1980 and December 1994 was undertaken. Mean follow-up was 45 months. Mean age was 57 years (range, 33 to 88 years). Forty-seven patients were heavy smokers. Symptoms included claudication in 81%, rest pain in 25%, and tissue loss in 15%. Impotence was documented in 73% of men. Associated arterial disease included inferior mesenteric artery occlusion in 31 patients, renal artery stenosis or occlusion in 12, superior mesenteric artery stenosis in two, and celiac artery stenosis in one.Methods: Forty inflow procedures were performed, including 17 thoracobifemoral bypass (TBF) procedures, 15 aortobifemoral/iliac bypass (ABFI) procedures, and eight axillo-bifemoral bypass (AXBF) procedures. Eight patients were managed without surgery. The thoracic aorta was chosen as the inflow source in 17 patients because of previous abdominal aortic surgery in eight, poor status of the abdominal aorta in eight, and horseshoe kidney in one. Results: The overall operative mortality rate was 5%, and the perioperative morbidity rate was 18%. There was no statistical difference in perioperative mortality and morbidity rates among the operative groups. The five-year survival rate (life-table) for all IRAO patients was 67%. TBF and ABFI revascularization procedures yielded 5-year patency rates of 71% and 79%, respectively ( p 2.0 mg/dl were documented in three operative patients and in one nonoperative patient, and none required dialysis.Conclusions: In patients who have IRAO, aorta-based inflow procedures are superior to AXBF both in hemodynamic outcome and in patency rates. Treatment of IRAO with TBF or ABFI yields similar long-term results; the descending thoracic aorta represents an excellent inflow alternative to the abdominal aorta. Clinically significant renal impairment is rarely associated with IRAO. Nonoperative management of IRAO is associated with an increased mortality rate and a high rate of limb loss. (J Vasc Surg 1996;24:394-405.

Prospective screening for postoperative deep venous thrombosis in patients undergoing infrainguinal revascularization

AbstractPurpose: The incidence of deep venous thrombosis (DVT) in patients undergoing infrainguinal bypass graft procedures has not been well documented, and the need for routine prophylaxis remains controversial. The purpose of this study was to prospectively evaluate the risk of postoperative DVT complicating infrainguinal revascularization. Methods: Seventy-four patients undergoing infrainguinal bypass graft procedures during a 12-month period were prospectively screened for DVT. Bilateral lower extremity venous duplex scan imaging was performed preoperatively and within 1 week and 6 weeks, postoperatively. Routine DVT prophylaxis was not used, with anticoagulation reserved for specific indications. Results: Of the 74 patients screened, three patients (4.1%) had DVT identified on preoperative venous duplex scan imaging and were excluded from the study. Of the remaining 71 patients enrolled, only two patients (2.8%) had postoperative DVT. Postoperative DVT was ipsilateral to the bypass graft extremity in both patients, with involvement of the peroneal vein in one patient and the femoral vein in the other. Although routine prophylaxis was not used, 18 of these patients (25%) were anticoagulated for other indications, with DVT occurring in one patient (5.6%). Of the remaining 53 patients who did not receive postoperative anticoagulation, only one patient (1.8%) had DVT. Conclusions: According to this prospective study, the risk of postoperative DVT in patients undergoing infrainguinal revascularization is low. Routine prophylaxis is not recommended, with postoperative anticoagulation reserved for specific indications. (J Vasc Surg 2000;32:669-75.

Descending thoracic aorta to iliofemoral artery bypass grafting: A role for primary revascularization for aortoiliac occlusive disease?

AbstractPurpose: Bypass grafts that originate from the descending thoracic aorta to the iliac or femoral arteries are well described but are not commonly used as primary procedures, and the long-term results remain unknown. A 15-year experience with 50 descending thoracic aorta to iliofemoral artery bypass grafts for aortoiliac occlusive disease is the basis of this report. Methods: From January 1983 to December 1997, patients who underwent bypass grafting procedures from the descending thoracic aorta to the iliac or femoral arteries were identified. Surgical indications, morbidity and mortality rates, primary and secondary patency rates, limb salvage rates, and survival rates were determined. Results: Fifty descending thoracic aorta to iliofemoral artery bypass grafting procedures were performed—24 (48%) for severe claudication, 22 (44%) for rest pain, and 4 (8%) for ischemic ulceration. A primary procedure was performed in 31 patients (62%) for complete occlusion (21 patients) and severe atherosclerotic disease (10 patients) of the infrarenal aorta. The indications for 19 secondary revascularizations (38%) were prior aortic or extra-anatomic graft failure in 17 cases and aortic graft infection in 2 cases. The follow-up periods ranged from 1 to 150 months (mean, 39 months). The cumulative life-table 5-year primary patency, secondary patency, limb salvage, and survival rates were 79%, 84%, 93%, and 67%, respectively. An improved patency trend was observed for patients who underwent operation for severe claudication as compared with limb-threatening ischemia (92% and 69%; P = .07). However, there was no difference between primary and secondary operations in primary patency rates (81% and 79%; P = NS) or survival rates (72% and 62%; P = NS). Conclusion: Descending thoracic aorta to iliofemoral artery bypass grafting has excellent overall long-term results. These results support its more liberal use for primary revascularization, especially for patients with severe atherosclerotic disease or complete occlusion of the infrarenal aorta. (J Vasc Surg 1999;29:249-58.

Prospective randomized comparison of surgical versus endovascular management of thrombosed dialysis access grafts

Abstract Purpose: Salvage of thrombosed prosthetic dialysis shunts can be performed using surgical or endovascular techniques. A prospective randomized trial was designed to compare the efficacy of these two methods in restoring dialysis access function. Methods: One hundred fifteen patients with thrombosed dialysis shunts were randomized prospectively to surgical (n = 56) or endovascular (n = 59) therapy. In the surgical group, salvage was attempted with thrombectomy alone in 22% and with thrombectomy plus graft revision in 78%. In the endovascular group, graft function was restored with mechanical (82%) or thrombolytic (18%) graft thrombectomy followed by percutaneous angioplasty. Results: Stenosis limited to the venous anastomotic area was the cause of shunt thrombosis in 55% of patients, and long-segment venous outflow stenosis or occlusion was the cause in 30%. In 83% of the surgical group and in 72% of the endovascular group, graft function was immediately restored ( p = NS). The postoperative graft function rate was significantly better in the surgical group ( p < 0.05). Thirty-six percent of grafts managed surgically remained functional at 6 months and 25% at 12 months. In the endovascular group, 11% were functional at 6 months and 9% by 12 months. Patients with long-segment venous outflow stenosis or occlusion had a significantly worse patency rate than those with venous anastomotic stenosis ( p < 0.05). Conclusions: Neither surgical nor endovascular management resulted in long-term function for the majority of shunts after thrombosis. However, surgical management resulted in significantly longer primary patency in this patient population, supporting its use as the primary method of management in most patients in whom shunt thrombosis develops

Descending thoracic aorta to iliofemoral artery bypass grafting: A role for primary revascularization for aortoiliac occlusive disease?

AbstractPurpose: Bypass grafts that originate from the descending thoracic aorta to the iliac or femoral arteries are well described but are not commonly used as primary procedures, and the long-term results remain unknown. A 15-year experience with 50 descending thoracic aorta to iliofemoral artery bypass grafts for aortoiliac occlusive disease is the basis of this report. Methods: From January 1983 to December 1997, patients who underwent bypass grafting procedures from the descending thoracic aorta to the iliac or femoral arteries were identified. Surgical indications, morbidity and mortality rates, primary and secondary patency rates, limb salvage rates, and survival rates were determined. Results: Fifty descending thoracic aorta to iliofemoral artery bypass grafting procedures were performed—24 (48%) for severe claudication, 22 (44%) for rest pain, and 4 (8%) for ischemic ulceration. A primary procedure was performed in 31 patients (62%) for complete occlusion (21 patients) and severe atherosclerotic disease (10 patients) of the infrarenal aorta. The indications for 19 secondary revascularizations (38%) were prior aortic or extra-anatomic graft failure in 17 cases and aortic graft infection in 2 cases. The follow-up periods ranged from 1 to 150 months (mean, 39 months). The cumulative life-table 5-year primary patency, secondary patency, limb salvage, and survival rates were 79%, 84%, 93%, and 67%, respectively. An improved patency trend was observed for patients who underwent operation for severe claudication as compared with limb-threatening ischemia (92% and 69%; P = .07). However, there was no difference between primary and secondary operations in primary patency rates (81% and 79%; P = NS) or survival rates (72% and 62%; P = NS). Conclusion: Descending thoracic aorta to iliofemoral artery bypass grafting has excellent overall long-term results. These results support its more liberal use for primary revascularization, especially for patients with severe atherosclerotic disease or complete occlusion of the infrarenal aorta. (J Vasc Surg 1999;29:249-58.

Elecsys CSF biomarker immunoassays demonstrate concordance with amyloid-PET imaging

Background: β-amyloid (Aβ) positron emission tomography (PET) imaging is currently the only Food and Drug Administration-approved method to support clinical diagnosis of Alzheimer\u27s disease (AD). However, numerous research studies support the use of cerebrospinal fluid (CSF) biomarkers, as a cost-efficient, quick and equally valid method to define AD pathology. Methods: Using automated Elecsys® assays (Roche Diagnostics) for Aβ (1-42) (Aβ42), Aβ (1-40) (Aβ40), total tau (tTau) and phosphorylated tau (181P) (pTau), we examined CSF samples from 202 participants of the Australian Imaging, Biomarkers and Lifestyle (AIBL) study of ageing cohort, to demonstrate the concordance with pathological AD via PET imaging. Results: Ratios Aβ42/Aβ40, tTau/Aβ42 and pTau/Aβ42 had higher receiver operator characteristic - area under the curve (all 0.94), and greater concordance with Aβ-PET (overall percentage agreement ~ 90%), compared with individual biomarkers. Conclusion: Strong concordance between CSF biomarkers and Aβ-PET status was observed overall, including for cognitively normal participants, further strengthening the association between these markers of AD neuropathological burden for both developmental research studies and for use in clinical trials. © 2020 The Author(s)

Reliability of Bioelectrical Impedance Analysis for Estimating Whole‐Fish Energy Density and Percent Lipids

We evaluated bioelectrical impedance analysis (BIA) as a nonlethal means of predicting energy density and percent lipids for three fish species: Yellow perch Perca flavescens, walleye Sander vitreus, and lake whitefish Coregonus clupeaformis. Although models that combined BIA measures with fish wet mass provided strong predictions of total energy, total lipids, and total dry mass for whole fish, including BIA provided only slightly better predictions than using fish mass alone. Regression models that used BIA measures to directly predict the energy density or percent lipids of whole fish were generally better than those using body mass alone (based on Akaike’s information criterion). However, the goodness of fit of models that used BIA measures varied widely across species and at best explained only slightly more than one‐half the variation observed in fish energy density or percent lipids. Models that combined BIA measures with body mass for prediction had the strongest correlations between predicted and observed energy density or percent lipids for a validation group of fish, but there were significant biases in these predictions. For example, the models underestimated energy density and percent lipids for lipid‐rich fish and overestimated energy density and percent lipids for lipid‐poor fish. A comparison of observed versus predicted whole‐fish energy densities and percent lipids demonstrated that models that incorporated BIA measures had lower maximum percent error than models without BIA measures in them, although the errors for the BIA models were still generally high (energy density: 15‐18%; percent lipids: 82‐89%). Considerable work is still required before BIA can provide reliable predictions of whole‐fish energy density and percent lipids, including understanding how temperature, electrode placement, and the variation in lipid distribution within a fish affect BIA measures.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141722/1/tafs1519.pd

Range-wide sources of variation in reproductive rates of northern spotted owls

We conducted a range-wide investigation of the dynamics of site-level reproductive rate of northern spotted owls using survey data from 11 study areas across the subspecies geographic range collected during 1993–2018. Our analytical approach accounted for imperfect detection of owl pairs and misclassification of successful reproduction (i.e., at least one young fledged) and contributed further insights into northern spotted owl population ecology and dynamics. Both nondetection and state misclassification were important, especially because factors affecting these sources of error also affected focal ecological parameters. Annual probabilities of site occupancy were greatest at sites with successful reproduction in the previous year and lowest for sites not occupied by a pair in the previous year. Site-specific occupancy transition probabilities declined over time and were negatively affected by barred owl presence. Overall, the site-specific probability of successful reproduction showed substantial year-to-year fluctuations and was similar for occupied sites that did or did not experience successful reproduction the previous year. Site-specific probabilities for successful reproduction were very small for sites that were unoccupied the previous year. Barred owl presence negatively affected the probability of successful reproduction by northern spotted owls in Washington and California, as predicted, but the effect in Oregon was mixed. The proportions of sites occupied by northern spotted owl pairs showed steep, near-monotonic declines over the study period, with all study areas showing the lowest observed levels of occupancy to date. If trends continue it is likely that northern spotted owls will become extirpated throughout large portions of their range in the coming decades

Sublithospheric diamond ages and the supercontinent cycle.

Subduction related to the ancient supercontinent cycle is poorly constrained by mantle samples. Sublithospheric diamond crystallization records the release of melts from subducting oceanic lithosphere at 300-700 km depths1,2 and is especially suited to tracking the timing and effects of deep mantle processes on supercontinents. Here we show that four isotope systems (Rb-Sr, Sm-Nd, U-Pb and Re-Os) applied to Fe-sulfide and CaSiO3 inclusions within 13 sublithospheric diamonds from Juína (Brazil) and Kankan (Guinea) give broadly overlapping crystallization ages from around 450 to 650 million years ago. The intracratonic location of the diamond deposits on Gondwana and the ages, initial isotopic ratios, and trace element content of the inclusions indicate formation from a peri-Gondwanan subduction system. Preservation of these Neoproterozoic-Palaeozoic sublithospheric diamonds beneath Gondwana until its Cretaceous breakup, coupled with majorite geobarometry3,4, suggests that they accreted to and were retained in the lithospheric keel for more than 300 Myr during supercontinent migration. We propose that this process of lithosphere growth-with diamonds attached to the supercontinent keel by the diapiric uprise of depleted buoyant material and pieces of slab crust-could have enhanced supercontinent stability