Critical Limb Ischemia in Patients with End-Stage Renal Disease: Do Long-Term Results Justify An Aggressive Surgical Approach?

End-stage renal disease (ESRD) patients probably represent the most difficult group of patients vascular surgeons are called upon to treat for critical limb ischemia. Advanced lower extremity arterial occlusive disease and frequent comorbidities make infrainguinal arterial bypass grafting (IABG) in this population both technically and medically challenging. Results of IABG are far inferior to those in non-ESRD patients. The greatest limitation to limb salvage appears to be progressive tissue necrosis and infection despite a patent bypass graft, a problem nearly unique to ESRD. Clinical predictors of outcome for IABG in this population have not been well established. The site and extent of tissue loss, the presence of associated infection, and the degree of pedal level occlusive disease have been identified as potentially important predictors. Improving outcome for ESRD patients with critical limb ischemia requires the establishment of firm guidelines for IABG to avoid futile and risky attempts at bypass in individuals better served by primary amputation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68696/2/10.1177_153100359901200114.pd

The Navigation Surface: A New Database Approach to Creating Multiple Products from High-density Surveys

High-resolution bathymetric surveys are revolutionising hydrographic surveying. ln addition to safety-of-navigation , there are a host of other uses for high-resolution bathymetry, including habitat mapping, hydrologic modelling, marine archaeology, and marine environmental protection. However, at present, there is no suitable method that can be used to produce multiple products that meet the needs of both navigation customers and other users . A research project conducted at the University of New Hampshire developed a model of the seafloor that is optimised for safety-of-navigation . This new technique bypasses the rather subjective, \u27selected soundings\u27 approach. Instead, a statistical model is created directly from the cleaned and processed data. The model - called a \u27navigation surface\u27 - consists of a high-resolution bathymetric grid with an uncertainty value assigned to each node on the grid. The model is then optimised to preserve the least depths over significant features . For each node an uncertainty value is computed which becomes an integral part of the model. The distribution of the points around the mean is combined with the predicted uncertainty of each measurement to form an overall uncertainty model. For low-density single-beam and lead-line surveys, the area between measurements is modelled based on a triangular irregular network (TIN). The uncertainty model then incorporates the distance from the measurement, as well as the uncertainty of the measurement itse lf

Investigation into Bias and Variability in Estimates of Population Size and Biomass when Catches of Individuals are Large Relative to the Total Population

Biomass of fish populations has traditionally been estimated by multiplying the average weight of captured fish by the estimated number of fish, with its variance estimated as the product of two variances. We present a method for estimating fish biomass in small streams (< 5 m wetted width) that uses a finite population correction factor (FPC) to take advantage of the fact that a relatively high proportion of the total population is normally captured and can be weighed during removal estimates. For these captured fish, measurement error is related to scale accuracy and field conditions. For the portion of the population that is not captured, we used a randomly stopped sums estimator (RSS) to estimate the total weight and variance of this non-captured proportion of the population. We also evaluated FPC and RSS methods individually to determine which of the four methods--(1) combination of FPC and RSS (FPCRSS), (2) traditional (hereafter OLD), (3) FPC, or (4) RSS—performed best. We also incorporated biomass estimates for fish that were captured, but not weighed, using length-weight regression predictions (FPCRSSreg). Performance of these estimators was evaluated using both simulated and field data. We based performance on reduction in the coefficient of variation (CV) of the biomass estimate and coverage of 95-percent confidence intervals (proportion of trials for which the 95-percent estimated biomass confidence intervals included the true biomass). The FPCRSS method had the narrowest CVs and the OLD method had the widest CVs for both the field and simulated data. Because of the high variance for the OLD method, 95-percent CIs for this method included the true biomass for a higher proportion of trials (nearly 100%) than 95-percent CIs for the FPCRSS method, but the coverage of the FPCRSS method for two-pass removal estimates was 80 percent or better for capture probabilities of 0.5 or higher. Using simulated data, we found that removal estimators are biased and that these biases are more pronounced at lower capture probabilities and lower population sizes. This bias in removal population estimators causes a bias in biomass estimates and was partly responsible for poorer coverage of 95-percent CIs. Our attempts to correct for population estimate bias resulted in much wider confidence intervals for both population and biomass estimates. For 607 field biomass estimates where all captured fish were weighed, the median CV for the FPCRSS method (0.05) was significantly lower (Wilcoxon sign-ranked test: P < 0.001) than the OLD method (0.76). When a portion of captured fish was not weighed, but estimated using length-weight regression relationships, the FPCRSSreg method had significantly lower CVs (median = 0.06; Wilcoxon sign-ranked test: P < 0.001, n = 130) than the old method (median = 0.86)

Lingual Raynaud\u27s Phenomenon after Surgical and Radiotherapeutic Intervention for Oral Squamous Cell Carcinoma

Raynaud\u27s phenomenon of the tongue after radiation therapy with or without chemotherapy is an exceedingly rare complication. Symptoms are similar to Raynaud\u27s disease of other sites and involve pallor and discomfort on exposure to cold temperatures that resolve with rewarming. Presentation occurs approximately 18-24 months after radiotherapy on average and can usually be managed effectively with lifestyle modification and pharmacotherapy. Here, we present a case of lingual Raynaud\u27s following surgery and adjuvant radiation therapy in a patient with squamous cell carcinoma of the oral cavity

Socioeconomic Disparities Do Not Affect Outcomes in Acute Limb Ischemia

Objective: The association between socioeconomic status (SES) and outcome after acute limb ischemia (ALI) is largely unknown. We aimed to determine whether SES is associated with worse presentations and outcomes for patients with ALI. Methods: We performed a retrospective review of a prospectively collected database containing all patients who had presented with ALI between April 2016 and October 2020 to a tertiary care center. SES was quantified using individual variables (median household income, level of education, employment) and a composite endpoint, the neighborhood deprivation index (NDI). The NDI is a standardized and reproducible index that uses census tract data, with a higher number indicating lower SES status. The NDI summarizes eight domains of socioeconomic deprivation. ALI severity was categorized using the Rutherford classification. The associations between SES and the severity of ALI at presentation and between SES and the outcomes were analyzed using bivariate analysis of variance, an independent t test, and multivariate logistic regression, as appropriate. Results: During the study period, 278 patients were treated for ALI, of whom 211 had complete SES data available. Their mean age was 64 years; 55% were men and 57% were white. The Rutherford classification of disease severity was grade 1, 2a, 2b, and 3 for 6%, 54%, 32%, and 8%, respectively. Patients with a low SES status using the NDI were more likely to have a history of peripheral arterial disease and chronic kidney disease at presentation (Table). The etiology (thrombotic vs embolic) was not associated with SES. No significant differences were seen between SES and the severity of ALI at presentation ( P = .96) or the treatment modality ( P = .80). We found no association between SES and either 30-day or 1-year limb loss or mortality (Table). Lower SES (higher NDI) was associated with increased 30-day readmissions ( P = .021). This association persisted on multivariate analysis ( P = .023). Conclusions: SES was not associated with the severity of ALI at presentation. Although SES was associated with the presence of peripheral arterial disease and chronic kidney disease at presentation and higher readmission rates for patients with ALI, SES was not a predictor of short-term or 1-year limb loss or mortality. In the present study, ALI presentation and treatment outcome were independent of SES

Performance of Westslope Cutthroat Trout Released into the Upper Cherry Creek Drainage Using Remote Stream Incubators

A major effort to conserve westslope cutthroat (Oncorhynchus clarkii lewisi; WCT) is underway throughout Montana. One of the larger WCT conservation projects is onging in the Cherry Creek drainage of the Madison River. About 105 km of stream and a mountain lake are being treated with piscicides to remove nonnative trout, and WCT are being introduced into the drainage using remote stream incubators (RSIs). We are evaluating the relative success of different wild and hatchery stocks of WCT released into Cherry Creek. Here, we report on survival, abundance, growth, condition, and dispersal of WCT in the upper Cherry Creek drainage during the first three years of releases. Two streams of similar size, upper Cherry Creek and Cherry Lake Creek, meet to form main Cherry Creek. Cherry Lake Creek is colder than upper Cherry Creek (average August temperature about 3?C colder).Known numbers of WCT embryos were placed into RSIs at two sites in upper Cherry Creek during 2006 and 2007, one site in Cherry Lake Creek during 2006 and 2007, one site in Pika Creek (a tributary to Cherry Lake Creek) during 2008, and in an un-named spring-fed tributary to main Cherry Creek just below the mouth of Cherry Lake Creek during 2008. Fry that hatched in each RSI were captured and counted prior to release. Population abundances were estimated by single and multiple-pass electrofishing in 100-m sample sections located systematically throughout the upper reaches of the drainage. Estimated survivals from egg to fry, fry to age- 1, age-1 to age-2, and age-2 to age-3 ranged from 13 to 80 percent, 7 to 80 percent, 21 to 100 percent, and 100 percent, respectively. Survivals in the colder stream, Cherry Lake Creek, were lower than in the warmer stream. Over 3500 WCT occupied the upper Cherry Creek drainage by 2009. Fish dispersed short distances upstream and long distances downstream, but downstream dispersal appeared relatively discrete, with WCT filling available habitat near RSIs before occupying reaches further downstream. Early growth of WCT was much slower in colder streams, but by age-3 little difference existed among streams. Conversely, condition factors of WCT were slightly lower in upper Cherry Creek (averaging 0.88 to 0.95) than in Cherry Lake Creek (0.92 to 1.11). The introduction of WCT in upper Cherry Creek has been successful to date; however, natural reproduction by introduced WCT has not yet occurred, but is expected to occur next year

Stronger but Not Faster : Flipped Classroom Teaching Significantly Improves Resident\u27s Skills but Not Speed

Objective: Flipped classroom teaching is a nontraditional education model where instructional content is delivered outside the classroom. This constructivist approach emphasizes self-direction, active inquiry; the instructor’s role is to foster critical reflection and facilitate the application and understanding of concepts. Our objective was to study the difference in time taken and quality of patch graft angioplasty performed by residents with and without flipped teaching. Methods: The study was set in a skills simulation teaching session overseen by attending surgeons. The intervention consisted of introducing a video outlining the technical aspects of patch graft angioplasty, watched before the session. The first group (2018 postgraduate year [PGY] 1 and 2 residents) was given instructions at the time of the class without a prior educational video or resources (Figs 1 and 2). The second group (2019, 2020 PGY 1 and 2 residents) was asked to watch a 20-minute video on the technical aspects of the procedure before the class. Participants then performed a standardized patch graft closure of a 1 cm arteriotomy using a polytetrafluoroethylene patch. The groups were timed. The quality of the closure was tested by assessing the number of leaks and the quantity of leak of the patch (Fig 3). Bivariate analysis sample t-tests were used for statistical analysis. P value \u3c.05 was considered significant. Pre- and post-session surveys were conducted to assess residents’ experience. Results: Forty-two residents (PGY 1 and 2) were enrolled in the study, 15 in nonintervention group 1 and 27 in intervention group 2, compared with 7 staff vascular surgeons. The mean completion time was 26 minutes (group 1) vs 27 minutes (group 2), P ¼ .6. The staff completion time was 12 minutes, P ¼ .001. The number of major leaks (not needle holes) was 2.0 (group 1) vs 1.6 (group 2), P ¼ .007, none for staff. The total quantity of leak was 42 mL (group 1) vs 15 mL (group 2), P ¼ .0001 (Table I). There was perceived improvement in skill on analyzing pre- and post-session surveys (Table II). Conclusions: A structured educational intervention, watching a video of a procedure before the skills session, did not change the time needed to complete the skill. There was improvement in the technical outcome of the procedure defined by a decrease in the total quantity of leak. Reversed classroom teaching significantly improves resident’s skill, not speed. There was also a perceived improvement in skill by participants. This is a pilot study and further instructional outcomes are being studied

Impact Of Preoperative Hemoglobina1c In Patients Undergoing Open Distal Vascular Procedures

Objective: The purpose of this study was to evaluate if preoperative hemoglobin (Hb) A1c levels was associated with worse outcomes in patients undergoing open lower extremity (LE) revascularization. Methods: A retrospective review of a statewide vascular surgery registry was queried for all patients who underwent open infrainguinal bypass or open LE thrombectomy procedures between January 2014 and June 2021. Patients were categorized into four groups depending on whether their plasma HbA1c was ≤6%, \u3e6% to ≤8%, \u3e8% to ≤10%, and \u3e10%. Regression models were used to evaluate the association between preoperative HbA1c and postoperative major adverse limb events (MALE), major adverse cardiac events (MACE), mortality, and length of stay (LOS). Results: A total of 5388 patients were included in the study. The average age was 66 years. Sixty-six percent of the cohort were male, and 78% were white. Demographics and comorbidities were associated with the HbA1c level. Mean LOS was 7 days for HbA1c \u3c6% and 10 days for HbA1c \u3e10% (P \u3c.001). No significant association was found when looking at perioperative MALE, MACE, 30-day mortality, or 1-year mortality. On multivariate analysis, only LOS remained significantly associated with the level of HbA1c (P \u3c.001) (Table). Conclusions: Suboptimal preoperative glycemic control in patients undergoing open LE vascular procedures for ischemia is associated with an increased risk of LOS. HbA1c level was not predictive of worse perioperative MACE, MALE, or mortality in this cohort. The increased in LOS could be explained by unmeasured complications, frailty, or increased hospitalization time needed to optimize glycemic control before discharge. [Formula presented

Impact of Preoperative Anemia in Patients Undergoing Peripheral Vascular Intervention

Objectives: Transcarotid artery revascularization (TCAR) is an emerging novel approach to carotid intervention, adopted and well-suited for high-risk patients. Our objective was to assess the outcomes of TCAR and determine its impact on the volume of carotid endarterectomy (CEA) and non-TCAR carotid artery stenting (CAS) in a single-state experience. Methods: A large statewide quality consortium registry was queried. The indications and outcomes of TCAR compared with CEA and non-TCAR CAS from January 2018 to October 2019 were reviewed. Non-TCAR CAS included transfemoral, transbrachial stenting and transcarotid stenting without the flow reversal technique. We also assessed the impact of TCAR on the trend of CEA and non-TCAR CAS performed, analyzing data from 2012 to 2019. Outcome comparisons were performed using the χ 2 and Mann-Whitney U tests, depending on the distribution of the outcomes. Results: A total of 438 TCARs were performed by 39 physicians in 16 hospitals; 60% of the patients were asymptomatic and 40% symptomatic. The TCAR indication was physiologic high risk for 369 patients (84%) and restenosis for 69 patients (16%), with most occurring after prior CEA (94%). Of the non-TCAR CAS cases, 94% were performed via transfemoral access. The patients undergoing non-TCAR CAS had the highest 30-day mortality ( P \u3c .001) and the highest incidence of 30-day new neurologic deficits ( P = .008) compared with the patients undergoing CEA and TCAR. CEA had the lowest myocardial infarction rate ( P = .015; Table). The number of TCAR procedures performed and the number of physicians and hospitals performing them increased during the 2-year period. Since the introduction of TCAR, no significant frequency decrease has occurred in the number of non-TCAR CAS or CEA cases by hospitals or physicians (Fig). However, a significant negative trend was found in the number of CEAs performed by physicians since 2012 ( P \u3c .001; Fig). Conclusions: TCAR is a safe method of carotid revascularization and is becoming an increasingly used method. TCAR has not affected the CEA hospital or physician volume since its introduction. CEA volumes and physician usage are declining, which could have future credentialing implications. In the present single-state experience, TCAR compared favorably with CEA and non-TCAR CAS might be less appealing because of its higher neurologic event rate