Aortobifemoral bypass vs covered endovascular reconstruction of aortic bifurcation.

BACKGROUND: Covered endovascular reconstruction of aortic bifurcation (CERAB) is increasingly used as a first line-treatment in patients with aortoiliac occlusive disease (AIOD). We sought to compare the outcomes of patients who underwent CERAB compared with the gold standard of aortobifemoral bypass (ABF). METHODS: The Vascular Quality Initiative was queried for patients who underwent ABF or CERAB from 2009 to 2021. Propensity scores were generated using demographics, comorbidities, Rutherford class, and urgency. The two groups were matched using 5-to-1 nearest-neighbor match. Our primary outcomes were 1-year estimates of primary patency, major adverse limb events (MALEs), MALE-free survival, reintervention-free survival, and amputation-free survival. Standard statistical methods were used. RESULTS: A total of 3944 ABF and 281 CERAB cases were identified. Of all patients with AIOD, the proportion of CERAB increased from 0% to 17.9% between 2009 and 2021. Compared with ABF, patients who underwent CERAB were more likely to be older (64.7 vs 60.2; P < .001) and more often had diabetes (40.9% vs 24.1%; P < .001) and end-stage renal disease (1.1% vs 0.3%; P = .03). In the matched analysis (229 CERAB vs 929 ABF), ABF patients had improved MALE-free survival (93.2% [±0.9%] vs 83.2% [±3%]; P < .001) and lower rates of MALE (5.2% [±0.9%] vs 14.1% [±3%]; P < .001), with comparable primary patency rates (98.3% [±0.3%] vs 96.6% [±1%]; P = .6) and amputation-free survival (99.3% [±0.3%] vs 99.4% [±0.6%]; P = .9). Patients in the CERAB group had significantly lower reintervention-free survival (62.5% [±6%] vs 92.9% [±0.9%]; P < .001). Matched analysis also revealed shorter length of stay (1 vs 7 days; P < .001), as well as lower pulmonary (1.2% vs 6.6%; P = .01), renal (1.8% vs 10%; P < .001), and cardiac (1.8% vs 12.8%; P < .001) complications among CERAB patients. CONCLUSIONS: CERAB had lower perioperative morbidity compared with ABF with a similar primary patency 1-year estimates. However, patients who underwent CERAB experienced more major adverse limb events and reinterventions. Although CERAB is an effective treatment for patients with AIOD, further studies are needed to determine the long-term outcomes of CERAB compared with the established durability of ABF and further define the role of CEARB in the treatment of AIOD.

Carotid Endarterectomy Should Not Be Recommended to End-Stage Kidney Disease Patients with Asymptomatic Carotid Artery Disease.

BACKGROUND: Carotid endarterectomy (CEA) for asymptomatic carotid artery disease is advised for patients with low perioperative stroke risk and life expectancy of 3-5 years. We sought to explore the role of risk stratification and postoperative medical management in identifying appropriate asymptomatic candidates for CEA in the end-stage kidney disease (ESKD) population. METHODS: We identified ESKD patients on dialysis from the United States Renal Data System that underwent CEA (2008-2014) for asymptomatic carotid artery disease. We used the Liu comorbidity index as well as a novel risk prediction model based on Cox proportional hazards model to stratify patients. The primary outcome evaluated was 3-year survival, and Kaplan-Meier methods were used to generate survival estimates. We further conducted a subanalysis of patients with Medicare part D data to determine postoperative usage of the following medications: statins, antiplatelets, and antihypertensives. We evaluated the association of medication utilization and 3-year survival using Kaplan-Meier methods and Cox proportional hazards modeling. RESULTS: We analyzed 1,813 patients meeting inclusion criteria. The population was predominantly older (mean age 70.2 ± 9.1), White (84.8%), and had a high prevalence of cardiovascular comorbidities, such as hypertension (90.7%), diabetes (62.5%), and congestive heart failure (35.4%). Among the entire cohort, 23.0% had a Liu comorbidity index ≤8, 35.0% had index 9-12, and 42.0% had index >12. Increasing Liu comorbidity index was associated with worse survival (P < 0.01); however, even the group with Liu index ≤8 had poor 3-year survival of 58.8% (53.9-63.4). The Cox proportional hazards model identified variables for inclusion in the risk model such as age >80 (adjusted hazard ratio [aHR] = 2.49, 95% confidence interval [CI] [1.87-3.33], P < 0.001), congestive heart failure (aHR = 1.31, 95% CI [1.14-1.51], P < 0.001), and Liu comorbidity index >12(aHR = 1.89, 95% CI [1.56-2.28], P < 0.001). The risk score generated ranged from 0 to 6.5, and patients were divided into 3 groups: score ≤2 (43.4%), 2-4 (41.2%), and >4 (15.4%). Increasing risk score was associated with worse survival (P < 0.01) but even the "low-risk" group had 3-year survival of 58.5% (54.9-61.9). Subanalysis of the 1,249 (68.8% of total) patients with part D data found that statins and calcium channel blocker use was associated with improved survival, although observed rates for patients on drug were still low. CONCLUSIONS: The overall long-term survival of ESKD patients undergoing CEA for asymptomatic carotid artery disease is low. Risk stratification and analysis of postoperative medical management did not identify a subgroup of patients with adequate 3-year survival. Hence, the preventive benefits of CEA are not realized in these patients.

Midterm Outcomes and Predictors of Failure of Lower Extremity Bypass to Para-Malleolar and Pedal Targets.

BACKGROUND: The frequency of distal lower extremity bypass (LEB) for infrapopliteal critical limb threatening ischemia (IP-CLTI) has significantly decreased. Our goal was to analyze the contemporary outcomes and factors associated with failure of LEB to para-malleolar and pedal targets. METHODS: We queried the Vascular Quality Initiative infrainguinal database from 2003 to 2021 to identify LEB to para-malleolar or pedal/plantar targets. Primary outcomes were graft patency, major adverse limb events [vascular reintervention, above ankle amputation] (MALE), and amputation-free survival at 2 years. Standard statistical methods were utilized. RESULTS: We identified 2331 LEB procedures (1,265 anterior tibial at ankle/dorsalis pedis, 783 posterior tibial at ankle, 283 tarsal/plantar). The prevalence of LEB bypasses to distal targets has significantly decreased from 13.37% of all LEB procedures in 2003-3.51% in 2021 (P < 0.001). The majority of cases presented with tissue loss (81.25. Common postoperative complications included major adverse cardiac events (8.9%) and surgical site infections (3.6%). Major amputations occurred in 16.8% of patients at 1 year. Postoperative mortality at 1 year was 10%. On unadjusted Kaplan-Meier survival analysis at 2 years, primary patency was 50.56% ± 3.6%, MALE was 63.49% ± 3.27%, and amputation-free survival was 71.71% ± 0.98%. In adjusted analyses [adjusted for comorbidities, indication, conduit type, urgency, prior vascular interventions, graft inflow vessel (femoral/popliteal), concomitant inflow procedures, surgeon and center volume] conduits other than great saphenous vein (P < 0.001) were associated with loss of primary patency and increased MALE. High center volume (>5 procedures/year) was associated with improved primary patency (P = 0.015), and lower MALE (P = 0.021) at 2 years. CONCLUSIONS: Despite decreased utilization, open surgical bypass to distal targets at the ankle remains a viable option for treatment of IP-CLTI with acceptable patency and amputation-free survival rates at 2 years. Bypasses to distal targets should be performed at high volume centers to optimize graft patency and limb salvage and minimize reinterventions.

Improved outpatient medical visit compliance with sociodemographic discrepancies in vascular telehealth evaluations.

OBJECTIVE: The COVID-19 (coronavirus disease 2019) pandemic has led to a rapid expansion in the use of telemedicine across all medical fields but has also exposed telehealth care disparities with differing access to technology across racial and ethnic groups. The objective of our study was to investigate the effects of telehealth on vascular visit compliance and to explore the effects of sociodemographic factors on vascular surgery outpatient telehealth usage during the COVID-19 pandemic. METHODS: Consecutive patients who had undergone an outpatient vascular surgery evaluation between February 24, 2020 (the launch of our telemedicine program) and December 31, 2020, were reviewed. The baseline demographic and outcomes were obtained from the electronic medical records. Telehealth and in-person evaluations were defined according to the patient's index visit during the study period. Medical visit compliance was established on completion of the telehealth or in-person encounter. We used χ2 tests and logistic regression analyses. RESULTS: A total of 23,553 outpatient visits had been scheduled for 10,587 patients during the study period. Of the outpatient visits, 1559 had been scheduled telehealth encounters compared with 21,994 scheduled in-person encounters. Of the scheduled outpatient encounters, 13,900 medical visits (59.0%) had been completed: 1183 telehealth visits and 12,717 in-person visits. The mean travel distance saved for the telehealth visits was 22.1 ± 27.1 miles, and the mean travel time saved was 46.3 ± 41.47 minutes. We noted no sociodemographic differences between the patients scheduled for telehealth vs in-person visits. We found a trend toward a lower proportion of African-American patients in the telehealth group vs the in-person group (7.8% vs 10.6%; P = .116), without statistical significance. A significantly higher rate of medical visit completion was found for the telehealth group compared with the in-person group (79.5% vs 59.4%; P < .001). Among the patients scheduled for an outpatient medical visit, a scheduled telemedicine evaluation (vs in-person) was associated with 2.3 times the odds of completing the medical visit (odds ratio, 2.31; 95% confidence interval, 2.05-2.61), adjusting for age, sex, race, ethnicity, language, and the distance between the patient's home zip code and the outpatient vascular center's zip code. Selecting for scheduled telemedicine visits, African-American race was associated with a decreased odds of telemedicine usage (odds ratio, 0.73; 95% confidence interval, 0.59-0.90) after adjusting for age, sex, ethnicity, language, and visit type. CONCLUSIONS: Use of the vascular surgery outpatient telehealth evaluation appeared to improve medical visit completion in our region with apparent sociodemographic disparities. Further studies are needed to confirm whether telemedicine expansion has improved access to care in other geographic areas.

Trends in mortality and postoperative complications among octogenarian patients undergoing carotid endarterectomy.

BACKGROUND: Elderly patients represent a large portion of patients undergoing vascular surgery. This study aims to assess the contemporary frequency of octogenarians undergoing carotid endarterectomy (CEA) and to evaluate their postoperative complications and survival rates. METHODS: The Vascular Quality Initiative (VQI) dataset was queried for patients who underwent elective CEA between 2012 and 2021. Patients aged >90 years were excluded, as well as emergent and combined cases. The population was divided into two age groups: <80 years and ≥80 years. Frailty scores were generated using Vascular Quality Initiative variables grouped into 11 domains historically associated with frailty. Patients with scores within the first 25th percentile, between the 25th and 50th percentile, and above the 75th percentile were categorized into low, medium, and high frailty classes, respectively. Procedural indications were defined as hard (stenosis ≥80% or ipsilateral neurologic symptoms) or soft. Primary outcomes of interest were 2-year stroke-free and 2-year overall survival comparing (i) octogenarians with nonoctogenarians and (ii) octogenarians by frailty class. Standard statistical methods were used. RESULTS: Overall, 83,745 cases were included in this analysis. Between 2012 and 2021, a consistent proportion averaging 17% of CEA patients were octogenarians. Among this age group, the proportion of patients undergoing CEA for hard indications increased over time from 43.7% to 63.8% (P < .001). This increase was accompanied by a statistically significant increase in the combined 30-day perioperative stroke and mortality rate from 1.56% in 2012 to 2.96% in 2021 (P = .019). A Kaplan-Meier analysis showed a significantly lower 2-year stroke-free survival among octogenarians compared with the younger group (78.1% vs 87.6%; P < .001). Similarly, there was a significantly lower 2-year overall survival among octogenarians compared with the younger group (90.5% vs 95.1%; P < .001). Multivariate Cox proportional hazard analyses showed that high frailty class was associated with increased 2-year stroke risk (hazard ratio, 2.26; 95% confidence interval, 1.61-3.17; P < .001) and 2-year mortality (hazard ratio, 2.43; 95% confidence interval, 1.71-3.47; P < .001). Repeat Kaplan-Meier analysis stratifying octogenarians by frailty class revealed that octogenarians with low frailty can have stroke-free and overall survival rates comparable with nonoctogenarians (88.2% vs 87.6% [P = .158] and 96.0% vs 95.1% [P = .151], respectively). CONCLUSIONS: Chronological age should not be regarded as a contraindication for CEA. Frailty score calculation is a better predictor for postoperative outcomes and is an appropriate tool to risk stratify octogenarians, aiding in the decision between best medical treatment or intervention. The risk benefit assessment for high frailty class octogenarians is paramount because the postoperative risks may outweigh the long-term survival benefits of the prophylactic CEA.

Trends in Utilization of Completion Imaging after Lower Extremity Bypass and Its Association with Major Adverse Limb Events and Loss of Primary Patency.

BACKGROUND: Failure following lower extremity bypasses (LEBs) isoften secondary to technical defects. Despite traditional teachings, routine use of completion imaging (CI) in LEB has been debated. This study assesses national trends of CI following LEBs and the association of routine CI with 1-year major adverse limb events (MALE) and 1-year loss of primary patency (LPP). METHODS: The Vascular Quality Initiative (VQI) LEB dataset from 2003-2020 was queried for patients who underwent elective bypass for occlusive disease. The cohort was divided based on surgeons' CI strategy at time of LEB, categorized as routine (≥80% of cases/year), selective (<80% of cases/year), or never. The cohort was further stratified by surgeon volume category [low (<25th percentile), medium (25th-75th percentile), or high (>75th percentile)]. The primary outcomes were 1-year MALE-free survival and 1-year loss of primary patency (LPP)-free survival. Our secondary outcomes were temporal trends in CI use and temporal trends in 1-year MALE rates. Standard statistical methods were utilized. RESULTS: We identified 37,919 LEBs; 7,143 in routine CI strategy cohort, 22,157 selective CI and 8,619 in never CI. Patients in the 3 cohorts had comparable baseline demographics and indications for bypass. There was a significant decrease in CI utilization from 77.2% in 2003 to 32.0% in 2020 (P < 0.001). Similar trends in CI use were observed in patients who underwent bypass to tibial outflows (86.0% in 2003 vs. 36.9% in 2020; P < 0.001). While the use of CI has decreased over time, 1-year MALE rates have increased from 44.4% in 2003 to 50.4% in 2020 (P < 0.001). On multivariate COX regression, however, no significant associations between CI use or CI strategy and risk of 1-year MALE or LPP was found. Procedures performed by high-volume surgeons carried a lower risk of 1-year MALE (HR: 0.84; 95% CI [0.75-0.95]; P = 0.006) and LPP (HR:0.83; 95% CI [0.71-0.97]; P < 0.001) compared to low-volume surgeons. Repeat adjusted analyses showed no association between CI (use or strategy) and our primary outcomes when the subgroups with tibial outflows were analyzed. Similarly, no associations were found between CI (use or strategy) and our primary outcomes when the subgroups based on surgeons' CI volume were evaluated. CONCLUSIONS: The use of CI, for both proximal and distal target bypasses, has decreased over time while 1-year MALE rates have increased. Adjusted analyses indicate no association between CI use and improved MALE or LPP survival at 1 year and all CI strategies were found to have equivalent outcomes.

Racial Disparities in Treatment Indications and Outcomes for Limb Ischemia.

BACKGROUND: Studies suggest that the Affordable Care Act (ACA) of 2014 has improved access to vascular care and vascular outcomes among patients suffering from peripheral arterial disease (PAD). We sought to examine the racial disparities that exist in patients with PAD who have undergone lower extremity bypass (LEB) or a peripheral vascular intervention (PVI) using the Vascular Quality initiative (VQI) database. METHODS: The VQI infrainguinal and PVI datasets were queried for patients receiving elective and urgent LEB or PVI between 2016, 2 years after ACA implementation, and in 2021. Patients undergoing interventions urgently/emergently or for aneurysm were excluded. The primary outcome was major adverse limb event (MALE-defined as any vascular reintervention or above-ankle amputation) free survival at 1 year. Standard statistical methods were utilized as appropriate. RESULTS: A total of 17,455 LEB and 87,475 PVIs were included in this analysis. Black persons present at a younger age when compared to non-Hispanic White persons (NHW) and are more likely to have diabetes, hypertension, end-stage renal disease (ESRD), and higher rates of prior amputation. Black persons are more likely to present with chronic limb-threatening ischemia (CLTI) rather than claudication, and in a more urgent setting. Postoperative outcomes show higher rates of major amputations among racial minorities, specifically Black persons for both LEB (1.8% vs. 0.8% P < 0.001) and PVI (20.8% vs. 16.8% P < 0.001). Black persons are at higher risk of 1-year MALE for LEB (36.7% vs. 29.9% P < 0.001) and PVI (31.0% vs. 21.7%; P < 0.001). Even after adjusting for confounding variables, Black persons have a higher risk of 1-year MALE for LEB, with an adjusted hazard ratio (aHR) of 1.15 (95% CI [1.05-1.26], P = 0.003) and PVI (aHR 1.18 95% CI [1.12-1.24], P < 0.001). Other major determinates of 1-year MALE on multivariate Cox regression included CLTI (LEB aHR 1.57 95% CI [1.43-1.72], P < 0.001; PVI aHR 2.29 95% CI [2.20-2.39], P < 0.001) and history of prior amputation (LEB aHR 1.35 95% CI [1.17-1.56], P < 0.001; PVI aHR 1.5 95% CI [1.4-1.6], P < 0.001). CONCLUSIONS: Compared to NHW persons, Black persons present with more advanced vascular disease regardless of the operative indication. Black persons are also at significantly higher risk of 1-year MALE. Despite some advances in more accessible care through the ACA of 2014, our observations suggest that Black persons still have significantly worse outcomes due to variety of variables that need further investigation.

Endovascular repair of abdominal and thoracoabdominal aneurysms using chimneys and periscopes is associated with poor outcomes.

OBJECTIVE: Chimneys and periscopes are often used to treat pararenal or thoracoabdominal aneurysms de novo or after failed open or endovascular repair. We sought to describe our institutional experience, given their limited success and questionable long-term outcomes. METHODS: We retrospectively reviewed the electronic records for patients treated with chimneys/periscopes from 1997 through 2020. Baseline characteristics, procedural details, periprocedural complications, reinterventions, and midterm outcomes were collected. RESULTS: Fifty-eight patients (86 vessels) were treated; the median follow-up was 32 months (range, 0.03-104 months). There were 36% (n = 21) juxta-renal, 2% (n = 1) para-visceral, and 21% (n = 12) thoracoabdominal aneurysms, and 41% (n = 24) had pararenal failure of prior endovascular aneurysm repair (n = 17) or open repair (n = 7). Stent configuration for the majority of the 86 vessels (n = 80; 93%) treated were chimney configuration (n = 6 periscopes; 7%). The most common stent graft utilized was Viabahn, and 8.1% (n = 7) were reinforced with a bare metal stent. Although the majority of the cases were elective, 36.2% (n = 21) of the cases were urgent/emergent. At the conclusion of the initial procedure, 16 of 58 patients had an endoleak (gutter, 50% [8/16]; type Ia, 25% [4/16]; and type II, 25% [4/16]). On follow-up, 14 of 58 patients developed one or more endoleaks, with the most common endoleaks being a gutter endoleak (35% [7/20]). Other endoleaks observed included 30% (6/20) type III, 15% (3/20) type Ia, 15% (3/20) type Ib, and 5% (1/20) type II. Eleven of 58 patients underwent interventions for one or more endoleak (gutter, 33% [5/15]; type Ib, 20% [3/15]; type II, 7% [1/15]; and type III, 40% [6/15]). Twelve of 58 patients returned to the operating room for one or more procedures during the index hospitalization (five laparotomies, three dialysis access, three acute limb ischemia, and four chimney/periscope interventions). Ten of 58 patients underwent angioplasty/stenting for chimney/periscope compression or occlusion during the follow-up period. Survival was 61.3% at 1 year by Kaplan-Meier analysis (75% for elective, 37% for urgent/emergent) (aneurysm-related death, 22%). Cox hazard modeling showed that aneurysm diameter (hazard ratio, 1.03; 95% confidence interval, 1.004-1.05; P = .02) and urgent/emergent interventions (hazard ratio, 3.6; 95% confidence interval, 1.33-9.74; P = .01) were predictors of mortality. CONCLUSIONS: Endovascular repair of aortic aneurysms with chimneys/periscopes is associated with poor outcomes, including limited technical success and aneurysm exclusion, as well as high morbidity and mortality, with a high rate of reinterventions both in the immediate postoperative period and on follow-up. They should be used only when other surgical or endovascular options are not possible.

Alternative autologous and biologic conduits have worse outcomes than prosthetic grafts for infrainguinal bypass in patients with chronic limb-threatening ischemia.

OBJECTIVE: Single segment great saphenous vein (GSV) is the preferred conduit in infrainguinal bypass. Alternative autologous conduits (AAC) and nonautologous biologic conduits (NABC) are thought to be a better alternative to traditional prosthetic conduits (PC) in the absence of GSV. In this study we analyzed the outcomes of these alternative conduits in lower extremity bypasses (LEB) in patients with chronic limb-threatening ischemia. METHODS: The Vascular Quality Initiative LEB database from 2003 to 2020 was queried for this study, to identify LEB in patients with chronic limb-threatening ischemia. Primary outcomes were graft patency, major adverse limb events (MALE), and MALE-free survival at 1 year. Standard statistical methods were used as appropriate. RESULTS: We identified 22,671 LEB procedures (12,810 GSV, 6002 PC, 1907 AAC, and 1952 NABC). Compared with the GSV group, the other conduit patients were significantly older, had more comorbidities, had an increased rate of prior lower extremity interventions, had a higher rate of infrageniculate bypass targets, and were less ambulatory at baseline. The PC, AAC, and NABC groups had significantly higher rates of postoperative morbidity compared with the GSV group. The PC group had a higher 30-day mortality compared with the GSV, AAC, and NABC groups (3% PC vs 2% GSV, 2% AAC, 2% NABC; P = .049). Both PC and NABC had higher 1-year mortality compared with GSV and AAC (13% PC and 13% NABC vs 10% GSV, 10% AAC; P = .02). In an adjusted Cox regression model (stratified by infrageniculate target and adjusted for age, comorbidities, and prior vascular interventions) PC was not significantly different from GSV, but AAC (hazard ratio [HR], 1.41; 95% confidence interval [CI], 1.19-1.67; P < .001) and NABC (HR, 1.9; 95% CI, 1.61-2.25; P < .001) were associated with an increased risk of loss of primary patency. A similar association with MALE was observed: both AAC (HR, 1.35; 95% CI, 1.15-1.58; P < .001) and NABC (HR, 1.8; 95% CI, 1.53-2.11; P < .001) were associated with an increased risk of MALE compared with GSV; PC was not significantly different from GSV. CONCLUSIONS: In the absence of GSV, alternative conduits (autologous or nonautologous biologic) do not confer a benefit with regard to graft patency or MALE compared with PCs. Increased operating time or costs associated with the use of these conduits is not justified based on this study.

The prevalence of Schmorl's nodes in osteoporotic vs normal patients: a Middle Eastern population study.

The study was conducted to establish the association of Schmorl's nodes and osteoporosis in a Middle Eastern cohort. The prevalence of SN in this sample was 41.1%. It was most frequent in the lumbar spine typically solitary central lesions. Over 88% Schmorl's node cases were osteoporotic/osteopenic and only 11.6% normal. INTRODUCTION: This study aims to identify the prevalence of Schmorl's nodes (SNs) in a cohort of Omani nationals, and also to determine any relation between osteoporosis and Schmorl's nodes. METHODS: This retrospective observational study was conducted on Omani nationals. One thousand three hundred and forty-eight DEXA scan patients were included. Of these, 545 patients had complete X-rays and MRI scans that would help determine the SN status. The X-rays and sagittal, coronal, and axial T2-weighted MR images were used to identify the presence and exact location of the Schmorl nodes by one orthopedic trainee and confirmed by the senior author. The correlation of each parameter with the presence of SN was analyzed by the independent-samples T test and one-way ANOVA. RESULTS: The overall prevalence of SN in this population sample appeared to be 41.1%. Over 88% of the SN-positive cases were either osteopenic or frankly osteoporotic by the WHO definition. Vast majority of SNs (87.1%) occurred in the lumbar spine and were central in location and mostly solitary. Statistical analysis of the data revealed significant correlation between osteopenia or osteoporosis and the presence of SNs. CONCLUSIONS: The prevalence of SN in the sample of Omanis studied was 41.1% and was most frequently seen in older men in the lumbar spine. It is strongly associated with osteoporosis/osteopenia (88.4%) and frequently presents as solitary central lesions.

Recent Progress, Challenges, and Opportunities of Membrane Distillation for Heavy Metals Removal.

Water is essential for the presence of life on this earth. However, water contamination due to the presence of heavy/toxic metals is one of the serious environmental issues for living beings. Several methods have been devoted to separating or removing those heavy metals from wastewater. Among them, membrane distillation (MD) has become one of the most attractive approaches due to its higher rejection rate than processes driven by pressure, lower energy consumption than traditional distillation processes. MD has gained significant attention for removing heavy metals than other techniques like ion exchange and adsorption in the last two decades. This review provides insight knowledge to the reader and focuses on how heavy metals impact humans and the environment, sources of heavy metals, current and especially removal methods using the MD method. Moreover, recent studies, challenges, and opportunities on MD membrane modules and heavy metal removal systems are discussed. More importantly, in this review, we have identified the gaps and opportunities that are required for enhancing the MD approach and its practical suitability for heavy metal removals. MD module and system showed high performance, proving their possible applications to remove heavy metal ions in water/wastewater treatment.

Female Gender is a Predictor of Lower Iliac Vein Stenting Patency Rates.

BACKGROUND: Iliac venous stenting (IVS) for thrombotic and nonthrombotic venous disease is increasingly used as evidence of the safety, efficacy and durability of these interventions increases. Female gender has been implicated as a predictor of failure in arterial endovascular interventions. We hypothesize that female gender could be predictive of patency rates of iliac vein stenting. METHODS: Consecutive patients who underwent IVS for thrombotic or nonthrombotic venous disease at our institution from 2007 until 2019 were identified and divided into groups based on gender. Operative notes, venograms, and the electronic health record were then queried to obtain operative details, co-morbid conditions, postoperative outcomes and stent patency. Study outcome was long term patency rate. The data was analyzed using chi-square, logistic regression, and Kaplan-Meier analysis as appropriate. RESULTS: A total of 200 consecutive patients (231 limbs) were identified in our retrospective analysis, with a mean age of 48.8 ± 17.3, and BMI of 31.6 ± 8.6. Of those, 119 (59.5%) patients, (131 [56.8%] limbs) were female. Comparisons between the gender groups revealed no difference in age, BMI, or preoperative comorbidities. There was no difference in type of venous disease between male (85% thrombotic, 15% nonthrombotic) and female (84% thrombotic, 16% nonthrombotic), P= 0.830. The male cohort was more likely to present with leg ulceration (17% vs. 4.6%, P = 0.002), and the female cohort was more likely to present with leg edema (98.5% vs. 93.0%, P= 0.03). The male cohort had a higher rate of caval (48% vs. 33.6%, P= 0.027) and infrainguinal stent extension. (11% vs. 6.9%, P= 0.02). Females had a higher rate of left sided stenting (80.9% vs. 66/0%, P= 0.010). There was no difference in the median stent diameter used between the cohorts. Primary patency at 5 years was significantly higher for the male cohort (94.1% vs. 74.4%, P= 0.01) On adjusted multivariable cox regression female gender was a predictor of loss of primary patency within 5 years (HR, 4.04; P= 0.007). CONCLUSIONS: In this single center retrospective analysis of IVS, male patients were found to have better primary stent patency compared to female.

Microbial Degradation, Spectral analysis and Toxicological Assessment of Malachite Green Dye by Streptomyces exfoliatus.

Malachite green (MG) dye is a common environmental pollutant that threatens human health and the integrity of the Earth's ecosystem. The aim of this study was to investigate the potential biodegradation of MG dye by actinomycetes species isolated from planted soil near an industrial water effluent in Cairo, Egypt. The Streptomyces isolate St 45 was selected according to its high efficiency for laccase production. It was identified as S. exfoliatus based on phenotype and 16S rRNA molecular analysis and was deposited in the NCBI GenBank with the gene accession number OL720220. Its growth kinetics were studied during an incubation time of 144 h, during which the growth rate was 0.4232 (µ/h), the duplication time (td) was 1.64 d, and multiplication rate (MR) was 0.61 h, with an MG decolorization value of 96% after 120 h of incubation at 25 °C. Eleven physical and nutritional factors (mannitol, frying oil waste, MgSO4, NH4NO3, NH4Cl, dye concentration, pH, agitation, temperature, inoculum size, and incubation time) were screened for significance in the biodegradation of MG by S. exfoliatus using PBD. Out of the eleven factors screened in PBD, five (dye concentration, frying oil waste, MgSO4, inoculum size, and pH) were shown to be significant in the decolorization process. Central composite design (CCD) was applied to optimize the biodegradation of MG. Maximum decolorization was attained using the following optimal conditions: food oil waste, 7.5 mL/L; MgSO4, 0.35 g/L; dye concentration, 0.04 g/L; pH, 4.0; and inoculum size, 12.5%. The products from the degradation of MG by S. exfoliatus were characterized using high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS). The results revealed the presence of several compounds, including leuco-malachite green, di(tert-butyl)(2-phenylethoxy) silane, 1,3-benzenedicarboxylic acid, bis(2-ethylhexyl) ester, 1,4-benzenedicarboxylic acid, bis(2-ethylhexyl) ester, 1,2-benzenedicarboxylic acid, di-n-octyl phthalate, and 1,2-benzenedicarboxylic acid, dioctyl ester. Moreover, the phytotoxicity, microbial toxicity, and cytotoxicity tests confirmed that the byproducts of MG degradation were not toxic to plants, microbes, or human cells. The results of this work implicate S. exfoliatus as a novel strain for MG biodegradation in different environments.

Learning anatomy before and during COVID-19 pandemic: Students' perceptions and exam performance.

The objective of our study was to explore the impact of COVID-19 pandemic on learning anatomy and to compare the students' perceptions of "face-to-face" and "online" anatomy teaching, and to assess their impact on student's performance. We used a descriptive, cross-sectional, questionnaire-based study that focused on a single cohort of undergraduate medial students who attended anatomy demonstrations, at the College of Medicine and Medical Sciences, Arabian Gulf University (CMMS-AGU), both pre-pandemic (face-to-face) during 2019-2020 and the pandemic (online) during 2020-2021. Students who participated in this study responded in favor of face-to-face demonstrations for better understanding of the spatial orientation of body organs and systems, the visualization of the anatomical relations between structures, understanding the difficult anatomical structures, understanding the clinical correlations, and making them more confident about their practical exams. On the other hand, students were in favor of online demonstrations for retaining key information, confidence levels on discussing anatomy learning needs, effective utilization of demonstration time, and lower stress associated with the online learning. Regarding anatomy exam scores, statistically significant difference was found between mean scores of online and onsite exams in one of the two analyzed multiple choice questions tests. However, there was a statistically significant difference between the mean scores of objective structured practical examination of online and onsite exams in the two analyzed tests. Furthermore, the majority of the students who participated in the survey prefer a mixture of both face-to-face and online anatomy demonstrations during the pandemic and also in the post-COVID-19 era.

Sustainable and fast saliva-based COVID-19 virus diagnosis kit using a novel GO-decorated Au/FBG sensor.

Monitoring the COVID-19 virus through patients' saliva is a favorable non-invasive specimen for diagnosis and infection control. In this study, salivary samples of COVID-19 patients collected from 6 patients with the median age of 58.5 years, ranging from 34 to 72 years (2 females and 4 males) were analyzed using an Au/fiber Bragg grating (FBG) probe decorated with GO. The probe measures the prevalence of positivity in saliva and the association between the virus density and changes to sensing elements. When the probe is immersed in patients' saliva, deviation of the detected light wavelength and intensity from healthy saliva indicate the presence of the virus and confirms infection. For a patient in the hyperinflammatory phase of desease, who has virus density of 1.2 × 108 copies/mL in saliva, the maximum wavelength shift and intensity changes after 1600 s were shown to be 1.12 nm and 2.01 dB, respectively. While for a patient in the early infection phase with 1.6 × 103 copies/mL, these values were 0.98 nm and 1.32 dB. The precise and highly sensitive FBG probe proposed in this study was found a reliable tool for quick detection of the COVID-19 virus within 10 s after exposure to patients' saliva in any stage of the disease.

Idiopathic ileal volvulus with multiple concomitant infections in a starving man.

BACKGROUND: Small bowel volvulus is defined as the torsion of the small intestine, potentially leading to bowel obstruction, gangrene and perforation. It is a rare condition, especially in adults. CASE PRESENTATION: A 30-year-old man was retrieved from the jungle with severe weight loss and abdominal symptoms. He succumbed to death despite 22 days of intensive medical treatment. An autopsy revealed a ruptured gangrenous ileal volvulus with peritonitis and subdiaphragmatic abscess. Further laboratory analysis detected systemic Candida tropicalis and intestinal gramnegative bacterial sepsis, systemic Zika virus viremia, leptospirosis complicating rhabdomyolysis and disseminated intravascular coagulopathy, Type I Herpes Simplex virus infection of the tongue and upper gastrointestinal tract. The cause of death was the ruptured ileal volvulus, complicated with upper gastrointestinal bleeding due to Herpes simplex virus esophagitis in a malnourished patient with resolving leptospirosis and underlying Zika virus co-infection. CONCLUSION: Rare clinical scenarios of adult-onset intestinal volvulus with concomitant multiple infections precludes clinical diagnosis and early treatment, leading to devastating consequences of clinical outcome. The positive clinical and postmortem correlation is a good learning lesson in many disciplines of medicine and science.

Morphological evaluation of the incisive canal with reference to gender and age: A cone-beam computed tomography study.

BACKGROUND: The incisive canal (IC) is an important anatomical structure in the premaxilla that should be considered during many dental procedures. AIMS: The objective of this study is to associate the IC morphology and dimensions with reference to gender and age by means of cone-beam computed tomography (CBCT). PATIENTS AND METHODS: A retrospective study was conducted using archived CBCT records of patients who sought treatment at the Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia. OnDemand 3D Imaging software was utilized in image reconstruction and measurement determination. The parameters evaluated were the IC shape and dimensions in a sagittal and coronal view at two levels: palatal opening and nasal opening. The variables were compared according to age and gender using one-way Analysis of Variance (ANOVA) and Kruskal Wallis tests. Confidence level was obtained at P < 0.05. RESULTS: Out of the 370 CBCT images assessed, only 100 images fulfilled the inclusion criteria; 50 males and 50 females. No substantial variance in IC shapes was found in both the sagittal and coronal perspectives with reference to age and gender. Likewise, there was no statistical variation in IC dimensions with reference to age. On the other hand, there was a statistical difference in IC length when correlated with gender as the male subjects had longer IC as compared to females (P < 0.01). CONCLUSION: There is no association between IC morphology, age and gender. However, substantial variation in IC length was observed between genders.

Wheat mitochondrial respiration shifts from the tricarboxylic acid cycle to the GABA shunt under salt stress.

Mitochondrial respiration and tricarboxylic acid (TCA) cycle activity are required during salt stress in plants to provide ATP and reductants for adaptive processes such as ion exclusion, compatible solute synthesis and reactive oxygen species (ROS) detoxification. However, there is a poor mechanistic understanding of how salinity affects mitochondrial metabolism, particularly respiratory substrate source. To determine the mechanism of respiratory changes under salt stress in wheat leaves, we conducted an integrated analysis of metabolite content, respiratory rate and targeted protein abundance measurements. Also, we investigated the direct effect of salt on mitochondrial enzyme activities. Salt-treated wheat leaves exhibit higher respiration rate and extensive metabolite changes. The activity of the TCA cycle enzymes pyruvate dehydrogenase complex and the 2-oxoglutarate dehydrogenase complex were shown to be directly salt-sensitive. Multiple lines of evidence showed that the γ-aminobutyric acid (GABA) shunt was activated under salt treatment. During salt exposure, key metabolic enzymes required for the cyclic operation of the TCA cycle are physiochemically inhibited by salt. This inhibition is overcome by increased GABA shunt activity, which provides an alternative carbon source for mitochondria that bypasses salt-sensitive enzymes, to facilitate the increased respiration of wheat leaves.

Femtosecond Compression Dynamics and Timing Jitter Suppression in a THz-driven Electron Bunch Compressor.

We present the first demonstration of THz driven bunch compression and timing stabilization of a relativistic electron beam. Quasi-single-cycle strong field THz radiation is used in a shorted parallel-plate structure to compress a few-fC beam with 2.5 MeV kinetic energy by a factor of 2.7, producing a 39 fs rms bunch length and a reduction in timing jitter by more than a factor of 2 to 31 fs rms. This THz driven technique offers a significant improvement to beam performance for applications like ultrafast electron diffraction, providing a critical step towards unprecedented timing resolution in ultrafast sciences, and other accelerator applications using femtosecond-scale electron beams.

Diagnostic and prognostic role of serum miR-20b, miR-17-3p, HOTAIR, and MALAT1 in diabetic retinopathy.

Noncoding RNAs are emerging biomarkers for many diseases including diabetic retinopathy (DR). This study aimed to measure the expression levels of serum miR-20b, miR-17-3p, HOTAIR, and MALAT1 in DR patients. A total of 80 patients diagnosed as type 2 diabetes (T2D) and 81 healthy subjects were recruited in this study. T2D patients were divided into three groups: nondiabetic retinopathy (NDR) group (30 patients), nonproliferative diabetic retinopathy (NPDR) group (30 patients), and proliferative diabetic retinopathy (PDR) group (20 patients). Quantitative real-time polymerase chain reaction (PCR) was used to assess the expression of serum miR-20b, miR-17-3p, HOTAIR, and MALAT1. We found a significant decrease in serum miR-20b and a significant increase in serum HOTAIR and MALAT1 in NDR patients compared to healthy subjects. Also, we revealed a significant decrease in serum miR-20b and miR-17-3p and a significant increase in serum HOTAIR and MALAT1 in each of NPDR and PDR groups when compared with healthy subjects. Furthermore, we reported a significant decrease in miR-20b and miR-17-3p and a significant increase in HOTAIR and MALAT1in DR as well as in PDR patients when compared with NDR patients. However, on comparing NPDR with NDR patients, no significant difference was observed regarding the expression levels of miR-20b and miR-17-3p, in contrast, significant elevation of serum HOTAIR and MALAT1 was found in NPDR. Moreover, we observed a significant decrease in serum miR-20b and miR-17-3p and a significant increase in serum HOTAIR and MALAT1 in PDR group relative to NPDR group. Receiver operating characteristic (ROC) curve was used for evaluating the diagnostic value of the examined serum noncoding RNAs as novel biochemical indicators detecting severity of DR. Our analyses suggested that the examined serum noncoding RNAs may discriminate DR (PDR and NPDR) from NDR. Furthermore, these noncoding RNAs (less importantly miR-17) can be used as promising novel biomarkers for prediction DR severity, distinguishing PDR from NPDR patients. We can conclude that serum miR-20b, miR-17-3p, HOTAIR, and MALAT1 may be used as noninvasive biomarkers for screening of DR and early diagnosis of PDR. © 2018 IUBMB Life, 71(3):310-320, 2019.