Spectroscopic detection of bioaerosols with the wibs-4+: Anthropogenic and meteorological impacts.

This research builds upon a previous study that explored the potential of the modified WIBS-4+ to selectively differentiate and detect different bioaerosol classes. The current work evaluates the influence of meteorological and air quality parameters on bioaerosol concentrations, specifically pollen and fungal spore dynamics. Temperature was found to be the most influential parameter in terms of pollen production and release, showing a strong positive correlation. Wind data analysis provided insights into the potential geographic origins of pollen and fungal spore concentrations. Fungal spores were primarily shown to originate from a westerly direction, corresponding to agricultural land use, whereas pollen largely originated from a North-easterly direction, corresponding to several forests. The influence of air quality was also analysed to understand its potential impact on the WIBS fluorescent parameters investigated. Most parameters had a negative association with fungal spore concentrations, whereas several anthropogenic influences showed notable positive correlations with daily pollen concentrations. This is attributed to similar driving forces (meteorological parameters) and geographical origins. In addition, the WIBS showed a significant correlation with anthropogenic pollutants originating from combustion sources, suggesting the potential for such modified spectroscopic instruments to be utilized as air quality monitors. By combining all meteorological and pollution data along with WIBS-4+ channel data, a set of Multiple Linear Regression (MLR) analyses were completed. Successful results with R2 values ranging from 0.6 to 0.8 were recorded. The inclusion of meteorological parameters was dependent on the spore or pollen type being examined.

Greater difference between airborne and flower pollen chemistry, than between pollen collected across a pollution gradient in the Netherlands.

The prevalence in allergic diseases has increased considerably in the past decades. An important trigger of the symptoms of allergic rhinitis (hay fever) is the pollen of wind-pollinating plants. This pollen is developed by plants and is released into the air where it gets exposed to environmental influences and air pollution. We investigated the chemical changes to pollen that occur after release from the flower in a rural (Veluwe) and an urban (Amsterdam) site in the Netherlands using Fourier Transform Infrared (FTIR) spectroscopy. During the spring/summer of 2020 (during the COVID pandemic) the pollen of nine taxa (Alnus, Betula, Fagus, Fraxinus, Pinus, Plantago, Poaceae, Quercus and Salix) were collected directly from flowers and the air (using a mobile sampler). FTIR spectra were obtained for multiple individual pollen grains for each taxa. The spectra obtained from airborne pollen collected at the rural vs. urban sites did not show any statistical difference. This is possibly a result of a reduced difference in pollutant concentrations between the two sites due to the COVID-19-lockdown measures were in place. However, consistent differences in the FTIR spectra recovered from airborne vs. flower pollen were recorded for all pollen taxa. After the release from the flower the chemical composition of the pollen changed: (i) polysaccharides are converted to monosaccharides; (ii) protein concentration and/or nitration/oxidation level is altered; (iii) lipids are modified and/or reduced in concentration. These changes may alter the allergenicity of the pollen and suggest that further work on the allergenic nature of airborne pollen is required.

Characterization of Volatile and Particulate Emissions from Desktop 3D Printers.

The rapid expansion of 3D printing technologies has led to increased utilization in various industries and has also become pervasive in the home environment. Although the benefits are well acknowledged, concerns have arisen regarding potential health and safety hazards associated with emissions of volatile organic compounds (VOCs) and particulates during the 3D printing process. The home environment is particularly hazardous given the lack of health and safety awareness of the typical home user. This study aims to assess the safety aspects of 3D printing of PLA and ABS filaments by investigating emissions of VOCs and particulates, characterizing their chemical and physical profiles, and evaluating potential health risks. Gas chromatography-mass spectrometry (GC-MS) was employed to profile VOC emissions, while a particle analyzer (WIBS) was used to quantify and characterize particulate emissions. Our research highlights that 3D printing processes release a wide range of VOCs, including straight and branched alkanes, benzenes, and aldehydes. Emission profiles depend on filament type but also, importantly, the brand of filament. The size, shape, and fluorescent characteristics of particle emissions were characterized for PLA-based printing emissions and found to vary depending on the filament employed. This is the first 3D printing study employing WIBS for particulate characterization, and distinct sizes and shape profiles that differ from other ambient WIBS studies were observed. The findings emphasize the importance of implementing safety measures in all 3D printing environments, including the home, such as improved ventilation, thermoplastic material, and brand selection. Additionally, our research highlights the need for further regulatory guidelines to ensure the safe use of 3D printing technologies, particularly in the home setting.

Towards European automatic bioaerosol monitoring: Comparison of 9 automatic pollen observational instruments with classic Hirst-type traps.

To benefit allergy patients and the medical practitioners, pollen information should be available in both a reliable and timely manner; the latter is only recently possible due to automatic monitoring. To evaluate the performance of all currently available automatic instruments, an international intercomparison campaign was jointly organised by the EUMETNET AutoPollen Programme and the ADOPT COST Action in Munich, Germany (March-July 2021). The automatic systems (hardware plus identification algorithms) were compared with manual Hirst-type traps. Measurements were aggregated into 3-hourly or daily values to allow comparison across all devices. We report results for total pollen as well as for Betula, Fraxinus, Poaceae, and Quercus, for all instruments that provided these data. The results for daily averages compared better with Hirst observations than the 3-hourly values. For total pollen, there was a considerable spread among systems, with some reaching R2 > 0.6 (3 h) and R2 > 0.75 (daily) compared with Hirst-type traps, whilst other systems were not suitable to sample total pollen efficiently (R2 < 0.3). For individual pollen types, results similar to the Hirst were frequently shown by a small group of systems. For Betula, almost all systems performed well (R2 > 0.75 for 9 systems for 3-hourly data). Results for Fraxinus and Quercus were not as good for most systems, while for Poaceae (with some exceptions), the performance was weakest. For all pollen types and for most measurement systems, false positive classifications were observed outside of the main pollen season. Different algorithms applied to the same device also showed different results, highlighting the importance of this aspect of the measurement system. Overall, given the 30 % error on daily concentrations that is currently accepted for Hirst-type traps, several automatic systems are currently capable of being used operationally to provide real-time observations at high temporal resolutions. They provide distinct advantages compared to the manual Hirst-type measurements.

A Modified Spectroscopic Approach for the Real-Time Detection of Pollen and Fungal Spores at a Semi-Urban Site Using the WIBS-4+, Part I.

The real-time monitoring of primary biological aerosol particles (PBAP) such as pollen and fungal spores has received much attention in recent years as a result of their health and climatic effects. In this study, the Wideband Integrated Bioaerosol Sensor (WIBS) 4+ model was evaluated for its ability to sample and detect ambient fungal spore and pollen concentrations, compared to the traditional Hirst volumetric method. Although the determination of total pollen and fungal spore ambient concentrations are of interest, the selective detection of individual pollen/fungal spore types are often of greater allergenic/agricultural concern. To aid in this endeavour, modifications were made to the WIBS-4 instrument to target chlorophyll fluorescence. Two additional fluorescence channels (FL4 and FL5 channels) were combined with the standard WIBS channels (FL1, FL2, FL3). The purpose of this modification is to help discriminate between grass and herb pollen from other pollen. The WIBS-4+ was able to successfully detect and differentiate between different bioaerosol classes. The addition of the FL4 and FL5 channels also allowed for the improved differentiation between tree (R2 = 0.8), herbaceous (R2 = 0.6) and grass (R2 = 0.4) pollen and fungal spores (R2 = 0.8). Both grass and herbaceous pollen types showed a high correlation with D type particles, showing strong fluorescence in the FL4 channel. The additional fluorescent data that were introduced also improved clustering attempts, making k-means clustering a comparable solution for this high-resolution data.

A comprehensive aerobiological study of the airborne pollen in the Irish environment.

Respiratory allergies triggered by pollen allergens represent a significant health concern to the Irish public. Up to now, Ireland has largely refrained from participating in long-term aerobiological studies. Recently, pollen monitoring has commenced in several sampling locations around Ireland. The first results of the pollen monitoring campaigns for Dublin (urban) and Carlow (rural) concerning the period 2017-2019 and 2018-2019, respectively, are presented herein. Additional unpublished pollen data from 1978-1980 and, 2010-2011 were also incorporated in creating the first pollen calendar for Dublin. During the monitoring period over 60 pollen types were identified with an average Annual Pollen Integral (APIn) of 32,217 Pollen × day/m3 for Dublin and 78,411 Pollen × day/m3 for Carlow. The most prevalent pollen types in Dublin were: Poaceae (32%), Urticaceae (29%), Cupressaceae/Taxaceae (11%), Betula (10%), Quercus (4%), Pinus (3%), Fraxinus (2%), Alnus (2%) and Platanus (1%). The predominant pollen types in Carlow were identified as Poaceae (70%), Urticaceae (12%), Betula (10%), Quercus (2%), Fraxinus (1%) and Pinus (1%). These prevalent pollen types increased in annual pollen concentration in both locations from 2018 to 2019 except for Fraxinus. Although higher pollen concentrations were observed for the Carlow (rural) site a greater variety of pollen types were identified for the Dublin (urban) site. The general annual trend in the pollen season began with the release of tree pollen in early spring, followed by the release of grass and herbaceous pollen which dominated the summer months with the annual pollen season coming to an end in October. This behaviour was illustrated for 21 different pollen types in the Dublin pollen calendar. The correlation between ambient pollen concentration and meteorological parameters was also examined and differed greatly depending on the location and study year. A striking feature was a substantial fraction of the recorded pollen sampled in Dublin did not correlate with the prevailing wind directions. However, using non-parametric wind regression, specific source regions could be determined such as Alnus originating from the Southeast, Betula originating from the East and Poaceae originating from the Southwest. Supplementary Information: The online version contains supplementary material available at 10.1007/s10453-022-09751-w.

Survival after endovascular therapy in patients with ruptured thoracic aortic diseases: Results from the Global Registry for Endovascular Aortic Treatment Registry.

OBJECTIVE: The Global Registry for Endovascular Aortic Treatment is a prospective observational multicenter cohort registry of all Gore aortic endografts for a variety of aortic pathologies. The purpose of this study was to evaluate the outcome of the Conformable GORE TAG Thoracic Endoprosthesis and GORE TAG Thoracic Endoprosthesis devices for ruptured thoracic aortic syndromes. METHODS: Between December 2010 and October 2016, a total of 5018 patients were enrolled from 114 international sites in this registry. The database was queried for patients with at least one of the following pathologies: descending thoracic aortic aneurysm with rupture, thoracoabdominal aortic aneurysm rupture, descending aortic dissection rupture, and aortic arch aneurysm rupture. Patient demographics, operative details, and clinical outcomes were analyzed. RESULTS: A total of 40 patients were treated with a ruptured thoracic aortic disease (62.5% male; mean age, 67.5 ± 14.1 years). Nineteen patients were treated for descending thoracic aneurysm rupture, 9 for thoracoabdominal aneurysm rupture, 7 for descending aortic dissection rupture, and 5 for aortic arch aneurysm rupture. Technical success was achieved in 40 of 40 patients (100%). There were no intraoperative mortalities and no conversions to an open procedure. A total of 12 patients (30.0%) required intervention for involvement of at least one aortic branch vessel (4 covered, 5 surgically debranched, 1 stented, and 6 chimney technique). The 30-day mortality was four patients (10.0%). Early reintervention (≤30 days) was required in seven patients (17.5%), five of which were device related. There was a total of five endoleaks and all five required a reintervention. The median follow-up duration was 14.7 months (range, 1-57 months). Freedom from device-related intervention at 1 year was 87.1% (95% confidence interval, [CI], 0.716-0.944), at 2 years was 81.3% (95% CI 0.607-0.917) and at 3 years was 73.1% (95% CI, 0.47-0.878). Freedom from all-cause mortality at 1 year was 65.0% (95% CI, 0.474-0.780), at 2 years was 61.2% (95% CI, 0.431-0.751), and at 3 years was 56.1% (95% CI, 0.369-0.715). CONCLUSIONS: The Conformable GORE TAG Thoracic Endoprosthesis and GORE TAG Thoracic Endoprosthesis thoracic endografts provide an effective treatment for ruptured thoracic aortic diseases. Adjunctive coverage or revascularization of an aortic branch vessel may be necessary. Longer follow-up and larger studies are needed to determine durability of these repairs.

Fifty years of hemodialysis access literature: The fifty most cited publications in the medical literature.

Objectives The modern era of hemodialysis access surgery began with the publication in 1966 by Brescia et al. describing the use of a surgically created arteriovenous fistula. Since then, the number of patients on chronic hemodialysis and the number of publications dealing with hemodialysis access have steadily increased. We have chronicled the increase in publications in the medical literature dealing with hemodialysis access by evaluating the characteristics of the 50 most cited articles. Methods We queried the Science Citation Index from the years 1960-2014. Articles were selected based on a subject search and were ranked according to the number of times they were cited in the medical literature. Results The 50 most frequently cited articles were selected for further analysis and the number of annual publications was tracked. The landmark publication by Dr Brescia et al. was unequivocally the most cited article dealing with hemodialysis access (1109 citations). The subject matter of the papers included AV fistula and graft (9), hemodialysis catheter (9), complications and outcomes (24), and other topics (8). Most articles were published in nephrology journals (33), with fewer in surgery (7), medicine (7), and radiology (3) journals. Of the 17 journals represented, Kidney International was the clear leader, publishing 18 articles. There has been an exponential rise in the frequency of publications regarding dialysis access with 42 of 50 analyzed papers being authored after 1990. Conclusion As the number of patients on hemodialysis has increased dramatically over the past five decades, there has been a commensurate increase in the overall number of publications related to hemodialysis access.

On-line monitoring of airborne bioaerosols released from a composting/green waste site.

This study is the first to employ the on-line WIBS-4 (Wideband Integrated Bioaerosol Sensor) technique for the monitoring of bioaerosol emissions and non-fluorescing "dust" released from a composting/green waste site. The purpose of the research was to provide a "proof of principle" for using WIBS to monitor such a location continually over days and nights in order to construct comparative "bioaerosol site profiles". The real-time data obtained was then used to assess variations of the bioaerosol counts as a function of size, "shape", site location, working activity levels, time of day, relative humidity, wind speeds and wind directions. Three short campaigns were undertaken, one classified as a "light" workload period, another as a "heavy" workload period and finally a weekend when the site was closed. One main bioaerosol size regime was found to predominate: 0.5-3µm with morphologies ranging from elongated to ellipsoidal/spherical. The real-time number-concentration data provides a long-term "video" record of the site and were consistent with the Andersen sampling protocol performed that provides only a single "snapshot" for bioaerosol release. The number-concentration of fluorescent particles as a proportion of total particle counts amounted, on average, to ∼1% for the "light" workday period, ∼7% for the "heavy" workday period and ∼18% for the weekend. The bioaerosol release profiles at the weekend were considerably different from those monitored during the working weekdays.

Stent graft repair of paraanastomotic aneurysms after open descending thoracic and thoracoabdominal aortic aneurysm repair.

BACKGROUND: After open thoracic and thoracoabdominal aortic aneurysm repair, anastomotic aneurysms can form at or near the suture lines of the graft. Endovascular repair is an alternative to complicated reoperative open surgery. We report on our experience with endovascular treatment of these lesions. METHODS: A prospectively maintained database of endovascular thoracic aortic aneurysm repairs (TEVARs) performed at Mount Sinai Medical Center was reviewed and the initial procedures, comorbidities, clinical presentation, aneurysm characteristics, type of endograft, adjunctive procedures, and follow-up were analyzed. RESULTS: Of the 135 TEVAR procedures performed between June 2001 and December 2008, 9 patients had anastomotic aneurysms after a previous open repair. The mean age was 66.7 (range 41-89) years, 67% of whom were male. Of these 9 patients, 5 had a descending thoracic repair, 3 had a type IV repair, and 1 had a type II thoracoabdominal repair. Aneurysm formation occurred in the following regions: proximal anastomosis (n = 2); intercostal patch (n = 1); distal anastomosis (n = 3); visceral patch (n = 2); and midgraft (n = 1). The initial technical success rate was 100%, with 8 patients receiving a thoracic tube graft and 1 a modular bifurcated device. Two patients required an adjunctive carotid-subclavian bypass and 2 required extraanatomic revascularization of the visceral arteries. Mean follow-up was 16.5 months. There was 1 perioperative death secondary to a postoperative myocardial infarction. Three patients developed an endoleak with 1 requiring an intervention. One patient required an open thoracoabdominal repair at 3 months for a penetrating ulcer at the visceral segment and another died from a ruptured thoracic aneurysm proximal to the stent graft at 72 months. Two more died during the follow-up period of non-aneurysm-related causes. Five patients had paraanastomotic shrinkage or no change and 1 had an increase in size, and 3 had no follow-up imaging. CONCLUSIONS: Stent graft repair of paraanastomotic aneurysms after open descending thoracic and thoracoabdomninal repair is a reasonable option when patients have suitable anatomy. These patients, however, require close follow-up for the development of aneurysmal degeneration adjacent to the stent graft repair.

Hemoglobin A1c as a measure of disease severity and outcome in limb threatening ischemia.

BACKGROUND: Diabetes mellitus is a known risk factor in the development of peripheral vascular disease. Hemoglobin A1c (HbA1c) has been used by clinicians as a means to measure short to intermediate term glucose control in diabetics. Trials evaluating tight glucose control using HbA1c measurements have recently been conducted for several medical conditions. The goal of this study is to determine if the level of hemoglobin A1c has any effect on disease severity in diabetic patients with limb threatening ischemia. METHODS: A retrospective review of all patients presenting with limb threatening ischemia between January 1 and December 31, 2007 was conducted. All patients underwent conventional arteriography prior to intervention. Of 148 patients, 73 were diabetics with a hemoglobin A1c level performed within 3 mo of presentation. Patients were placed into high (>7) and low (<7) hemoglobin A1c groups and data was collected on type of presentation, comorbidities, anatomic level of disease, tibial artery patency, need for amputation, contralateral disease, need for an open versus an endovascular procedure, and freedom from intervention. Fisher's exact t-test was used to compare the two groups. A P value <0.05 was considered statistically significant. RESULTS: Thirty-six patients had HbA1c levels above 7.0 and 37 had levels below 7.0 (mean 7.64 ± 2.04, range 5.1-14.7). There were no statistically significant differences in the two groups in comorbities, average age, initial gangrene at presentation, aspirin or statin use, or smoking status. Patients in the high group were more likely to have had a previous attempt at revascularization (23 versus 11, P = 0.0049). There was no difference in the presence of contralateral disease (7 versus 4, P = 0.3447) or in the number of patent tibial vessels. Patients with low HbA1c levels were more likely to have the peroneal artery affected (17 versus 8, P = 0.048). In addition, TASC II classifications of iliac and femoral popliteal disease was similar between the two groups. Freedom from intervention is depicted graphically by life table analysis. CONCLUSION: Glucose control measured by hemoglobin A1c does not appear to affect severity of disease or need for reintervention in diabetics with limb threatening ischemia. This suggests other factors related to diabetes may play a role in peripheral vascular disease. Larger, prospective studies are needed to assess the affect of glucose control in limb threatening ischemia.

Is the length of follow-up evaluation in published reports on the treatment of infrainguinal occlusive disease decreasing?

BACKGROUND: There is increasing pressure for the rapid development and implementation of new techniques and procedures. This study examined whether or not there has been a trend toward increasingly short follow-up times for studies evaluating the treatment of lower-extremity occlusive disease. METHODS: A search was performed of PubMed using the term "femoropopliteal occlusive disease" from 1976 to 2006. Reports describing the open and/or endovascular treatment of femoropopliteal occlusive disease were classified according to the number of patients, method of treatment, and follow-up time. RESULTS: A total of 103 of the 435 reports met the inclusion criteria. Average follow-up times from 1976 to 1986 were a mean of 43.3 months and a median of 38.8 months, from 1986 to 1996 were a mean of 32.4 months and a median of 16.9 months, from 1996 to 2006 were a mean of 22.6 months and a median of 16.5 months. CONCLUSIONS: The number of reports on femoropopliteal occlusive disease treatment has increased. The length of follow-up period was 2- to 3-fold longer for reports on open procedures compared with those on endovascular procedures. Whether length of follow-up evaluation and reporting intervals should be standardized warrants further investigation.

Single-incision laparoscopic appendectomy: an early experience.

Acute appendicitis is one of the most common causes of abdominal pain that a general surgeon will encounter. We describe our modification to the laparoscopic appendectomy: a single-incision laparoscopic (SILS) appendectomy completed entirely intracorporeally. From September 2008 to September 2009, a retrospective review of the electronic medical record was performed in all patients who underwent a SILS appendectomy to specifically analyze the demographic characteristics, time in the operating room to perform SILS appendectomy, length of postoperative hospital stay, and postoperative complications. Twenty-five patients underwent SILS appendectomy in the study period. There were 18 males and seven females with a mean age of 41 ± 15 years and mean body mass index of 26.5 ± 5 kg/m². Single-incision laparoscopic appendectomy was performed successfully in all of our cases (100%). Mean operative time was 56 ± 16 minutes. Blood loss in all cases was minimal and there were no intraoperative complications. We successfully completed 25 appendectomies using the SILS method. Operative times were similar compared with the traditional laparoscopic technique. We believe that the SILS appendectomy is a safe and effective method that leaves a virtually invisible scar.

Proportion of patients with critical limb ischemia who require an open surgical procedure in a center favoring endovascular treatment.

Endovascular interventions have gained widespread acceptance as primary and secondary treatments for critical lower extremity ischemia (CLI), and many believe there is little need for open bypasses for CLI. Despite this, some patients presenting with CLI require traditional lower extremity bypass procedures at some point for successful limb salvage. To determine the proportion of patients requiring an open procedure, we reviewed our 1-year experience with CLI patients at a center committed to endovascular approaches whenever possible. We reviewed all patients presenting with CLI from January 1, 2007 to December 31, 2007. CLI was defined as ischemic rest pain, nonhealing ulceration, or gangrene for which a major amputation was imminently required. All patients underwent duplex and conventional angiography before intervention. Endovascular treatments were favored as primary, secondary, or tertiary treatments, if possible. If these failed or were impossible, standard lower extremity bypasses were performed. One hundred and forty-eight patients presented with primary, secondary, or tertiary CLI over this 1-year period. Of these, 63 (42%) were treated successfully with an endovascular intervention, and 69 (47%) required standard lower extremity bypass, and 16 (11%) required a combined endovascular and open procedure (i.e., hybrid procedure). Of these 148 patients, 46 (31%) were presenting with secondary, tertiary, or more CLI after failed previous (1-5) procedures. Despite the initial enthusiasm that the majority of patients presenting with CLI may be treated with endovascular procedures, there exists a significant cohort of patients that will ultimately require standard open surgical procedures.

Incidence and characteristics of venous thromboembolic disease during pregnancy and the postnatal period: a contemporary series.

BACKGROUND: To evaluate the incidence and characteristics of venous thromboembolic events (VTE) associated with pregnancy in a contemporary patient series. METHODS: We performed a retrospective review of 33,311 deliveries between June 2003 and June 2008. Patients with objective documentation of a VTE during pregnancy or the 3-month postnatal period were identified from hospital discharge International Classification of Disease Codes edition 9 codes. Diagnosis of deep venous thrombosis (DVT) was largely made by a Duplex ultrasound, whereas pulmonary embolism (PE) was diagnosed by a computerized tomographic angiography (CTA). RESULTS: Of 33,311 deliveries during the study period, 74 patients (0.22%) had a VTE. There were 40 incidents of DVT (0.12%) and 37 of PE (0.11%). DVT involved the iliac veins (6), the femoral or popliteal veins (16), the infrapopliteal veins (17), and the axillary vein (1). Most (57.5%) of the DVTs involved the left lower extremity. Thirty-eight (51.6%) of the VTEs occurred in the postnatal period, and of those 33 (87%) occurred within 1 week of delivery. Most of the postnatal VTEs (68%) were seen in patients who underwent a cesarean section. Among patients with VTE during pregnancy, there were 28% in the first trimester, 25% in the second, and 47% in the third. Events were distributed among maternal age groups as follows: 26% aged 13-24, 50% aged 25-34, and 24% aged 35-54. Of the 35 patients tested for a hypercoagulable disorder, 12 were found to have a positive test result. Five (6.8%) of these 74 patients had a prior history of VTE, with two having a hypercoagulable disorder. In addition, 45 of the 74 patients were on oral contraceptive therapy or received hormonal stimulation therapy before pregnancy. Patients with a VTE during pregnancy were treated with low molecular weight or unfractionated heparin. Most postnatal patients were treated with subcutaneous low molecular weight heparin and coumadin. Six inferior vena cava filters were placed in patients with bleeding complications as a result of anticoagulation. There were no deaths during the study period. CONCLUSIONS: Comparing our results with historic controls (DVT: 0.04-0.14% and PE: 0.003-0.04%), the incidence of DVT in pregnancy has not changed significantly. We note, however, that the incidence of pulmonary embolus in our series is higher than previously reported. CTA has been used for the diagnosis of PE since the past decade. The increase in the rate of PE in the current series may be because of the higher sensitivity of CTA when compared with previous diagnostic modalities.

Long-term outcome of inferior vena cava filter placement in patients undergoing gastric bypass.

BACKGROUND: It has been well established that inferior vena cava (IVC) filter placement at the time of open gastric bypass (OGB) surgery in patients with a body mass index of more than 55 kg/m(2) reduces both the pulmonary embolism rate and the perioperative mortality. However, little is known about the long-term effects of IVC filter placement in this particular group of patients. METHODS: Over an 8-year period, a total of 571 morbid obese patients underwent OGB procedures, and 58 (10%) of them required placement of an IVC filter before their procedure. All IVC filters were placed percutaneously through a femoral vein approach using a portable OEC fluoroscope. Types of IVC filters used in our study included the TrapEase (n = 35), Simon-Nitinol (n = 9), Greenfield (n = 2), and Bard Recovery (n = 12). RESULTS: Of the 58 patients who required an IVC placement, 56 remained free of any thromboembolic phenomena over the 8-year period (range, 1-8 years). The remaining two patients developed deep venous thrombosis. One patient was successfully treated with intravenous heparin and a 6-month course of Coumadin. She had complete resolution of her deep venous thrombosis and was incidentally noted to have a prothrombin 20210 gene mutation. The other patient, who had multiple gastric bypass complications, could not be successfully treated with intravenous heparin and thus progressed on to complete IVC thrombosis. She developed phlegmasia cerulea dolens and required bilateral above-the-knee amputations. She subsequently died 3 months after her procedures. CONCLUSION: It appears that IVC filter placement at the time of OGB surgery is a relatively benign intervention with a maximal benefit. A note of caution should be exerted for those obese patients who have a hypercoagulable disorder and for those who have complications related to the gastric bypass. An aggressive posture, which may consist of immediate anticoagulation after their procedures (only when it is deemed safe), should be advocated in this small sub-group of morbid obese patients.

Experience with a modified composite sequential bypass technique for limb-threatening ischemia.

BACKGROUND: Composite sequential femoro-popliteal-distal bypass is a valuable option for treatment of critical limb ischemia when autogenous vein is limited and an isolated popliteal or distal arterial segment exists. We report a modified technique for composite sequential bypass and the results with its use over a 14-year period. METHODS: Twenty-five modified composite sequential bypass procedures were performed on 24 patients to treat gangrene, ischemic ulceration, and severe rest pain. Vein grafts were anastomosed from blind popliteal or blind distal arterial segments above-knee (7) or below-knee (18) to a distal outflow vessel including the below-knee popliteal (1), posterior tibial (5), anterior tibial (7), or peroneal (12) artery. Polytetrafluoroethylene bypass grafts were then placed from a suitable inflow artery to the proximal hood of the vein graft. RESULTS: Cumulative primary patency rates were 80% at 3 years, and 65% at 5 years. The limb-salvage rate was 85% at 4 years. Occlusion of the prosthetic segment with a patent distal vein segment was recognized in two patients who presented with less severe recurrent ischemia. Limb-salvage in these patients was achieved by a secondary prosthetic graft to the patent vein graft. CONCLUSION: Our modified configuration of the prosthetic-vein anastomosis for composite sequential bypass is an alternative to the conventional procedure and may help preserve vein graft patency should the polytetrafluoroethylene graft thrombose.

Endovascular management of multiple arteriovenous fistulae following failed laser-assisted pacemaker lead extraction.

A woman presented for evaluation of new-onset left arm edema after failed laser-assisted pacemaker lead extraction. Initial workup demonstrated a left subclavian artery to vein arteriovenous fistula (AVF). She underwent repair of the AVF with placement of a covered stent in the subclavian artery, however, her symptoms did not completely resolve. Investigation revealed a left common carotid artery to left innominate vein AVF, which was repaired by deploying a covered stent retrograde into the left common carotid artery. Her symptoms subsequently resolved. Multiple iatrogenic AVF can be repaired endovascularly, however, a high degree of suspicion for multiple injuries should be maintained.