Real World Application of WIfI Scores in Peripheral Arterial Disease Patients.

OBJECTIVE: The Society for Vascular Surgery wound, ischemia, and foot infection (WIfI) classification system aims to risk stratify patients with chronic limb threatening ischemia (CLTI), predicting both amputation rates and the need for revascularization. However, real-world utilization of the system and whether it accurately predicts outcomes following open revascularization and peripheral interventions is unclear. Therefore, we sought to determine the adoption of the WIfI classification system within a contemporary statewide collaborative as well as the impact of patient factor, and WIfI risk assessment on short- and long-term outcomes. METHODS: Using data from a large statewide collaborative, we identified patients with CLTI undergoing open surgical revascularization or peripheral vascular intervention (PVI) between 2016 - 2022. The primary exposure was preoperative clinical WIfI stage. Patients were categorized according to the SVS Lower Extremity Threatened Limb Classification System into clinical WIfI stages1, 2, 3, or 4. The primary outcomes were 30-day and 1-year amputation and mortality. Multivariable logistic regression was performed to estimate the association of WIfI stage on post-revascularization outcomes. RESULTS: In the cohort of 17,417 patients, 83.4% (n=14,529) had WIfI stage documented. Peripheral vascular interventions (PVIs) were performed on 57.6% of patients, and 42.4% underwent an open surgical revascularization (OSR). 49.5% of patients were classified as stage 1, 19.3% stage 2, 12.8% stage 3 and 18.3% of patients met stage 4 criteria. Stage 3 and 4 patients had higher rates of diabetes, congestive heart failure, and renal failure, and were less likely to be current or former smokers. One-half of stage 3 patients underwent OSR, while stage 1 patients were most likely to have received a PVI (64%). As WIfI stage increased from 1 to 4, 1-year mortality increased from 12% to 21% (p<0.001), 30-day amputation rates increased from 5% to 38% (p<0.001), and 1-year amputation rates increased from 15% to 55% (p<0.001). Finally, patients who did not have WIfI scores classified had significantly higher 30-day and 1-year mortality, as well as higher 30-day and 1-year amputation rates. CONCLUSION: The Society for Vascular Surgery WIfI clinical stage is significantly associated with 1-year amputation rates in patients with CLTI following lower extremity revascularization. As nearly 55% of stage 4 patients require a major amputation within one year of intervention, this study supports use of the WIfI classification system in clinical decision making for patients with CLTI.

Comparative evaluation of transcutaneous oxygen tension vs ankle-brachial index as predictors of reoperation following below-knee amputation.

OBJECTIVE: Decision-making regarding level of lower extremity amputation is sometimes challenging. Selecting an appropriate anatomic level for major amputation requires consideration of tradeoffs between postoperative function and risk of wound complications that may require additional operations, including debridement and/or conversion to above-knee amputation (AKA). We evaluated the utility of common, non-invasive diagnostic tests used in clinical practice to predict the need for reoperations among patients undergoing primary, elective, below knee-amputations (BKAs) by vascular surgeons. METHODS: Patients undergoing elective BKA over a 5-year period were identified using Current Procedural Terminology codes. Medical records were reviewed to characterize demographics, pre-amputation testing transcutaneous oxygen tension (TcPO2), and ankle-brachial index (ABI). The need for ipsilateral post-BKA reoperation (including BKA revision and/or conversion to AKA) regardless of indication was the primary outcome. Associations were evaluated using univariable and multivariable logistic regression models. Cutpoints for TcPO2 values associated with amputation reoperation were evaluated using receiver operating characteristic curves. RESULTS: We identified 175 BKAs, of which 46 (26.3%) required ipsilateral reoperation (18.9% BKA revisions and 14.3% conversions to AKA). The mean age was 63.3 ± 14.8 years. Most patients were male (65.1%) and White (72.0%). Mean pre-amputation calf TcPO2 was 40.0 ± 20.5 mmHg, and mean ABI was 0.64 ± 0.45. In univariable models, post-BKA reoperation was associated with calf TcPO2 (odds ratio [OR], 0.97; 95% confidence interval [CI], 0.94-0.99; P = .013) but not ABI (OR, 0.53; 95% CI, 0.19-1.46; P = .217). Univariable associations with reoperation were also identified for age (OR, 0.97; 95% CI, 0.94-0.990; P = .003) and diabetes (OR, 0.43; 95% CI, 0.21-0.87; P = .019). No associations with amputation revision were identified for gender, race, end-stage renal disease, or preoperative antibiotics. Calf TcPO2 remained associated with post-BKA reoperation in a multivariable model (OR, 0.97; 95% CI, 0.94-0.99; P = .022) adjusted for age (OR, 0.98; 95% CI, 0.94-1.01; P = .222) and diabetes (OR, 0.98; 95% CI, 0.94-1.01; P = .559). Receiver operating characteristic analysis suggested a TcPO2 ≥38 mmHg as an appropriate cut-point for assessing risk for BKA revision (area under the curve = 0.682; negative predictive value, 0.91). CONCLUSIONS: Reoperation after BKA is common, and reoperation risk was associated with pre-amputation TcPO2. For patients undergoing elective BKA, higher risk of reoperation should be discussed with patients with an ipsilateral TcPO2 <38 mmHg.

Genome-wide association study suggests an independent genetic basis of zinc and cadmium concentrations in fresh sweet corn kernels.

Despite being one of the most consumed vegetables in the United States, the elemental profile of sweet corn (Zea mays L.) is limited in its dietary contributions. To address this through genetic improvement, a genome-wide association study was conducted for the concentrations of 15 elements in fresh kernels of a sweet corn association panel. In concordance with mapping results from mature maize kernels, we detected a probable pleiotropic association of zinc and iron concentrations with nicotianamine synthase5 (nas5), which purportedly encodes an enzyme involved in synthesis of the metal chelator nicotianamine. In addition, a pervasive association signal was identified for cadmium concentration within a recombination suppressed region on chromosome 2. The likely causal gene underlying this signal was heavy metal ATPase3 (hma3), whose counterpart in rice, OsHMA3, mediates vacuolar sequestration of cadmium and zinc in roots, whereby regulating zinc homeostasis and cadmium accumulation in grains. In our association panel, hma3 associated with cadmium but not zinc accumulation in fresh kernels. This finding implies that selection for low cadmium will not affect zinc levels in fresh kernels. Although less resolved association signals were detected for boron, nickel, and calcium, all 15 elements were shown to have moderate predictive abilities via whole-genome prediction. Collectively, these results help enhance our genomics-assisted breeding efforts centered on improving the elemental profile of fresh sweet corn kernels.

Exploring the rapid expansion of office-based laboratories and peripheral vascular interventions across the United States.

OBJECTIVE: To characterize the relationship between office-based laboratory (OBL) use and Medicare payments for peripheral vascular interventions (PVI). METHODS: Using the Centers for Medicare and Medicaid Services Provider Utilization and Payment Data Public Use Files from 2014 to 2017, we identified providers who performed percutaneous transluminal angioplasty, stent placement, and atherectomy. Procedures were aggregated at the provider and hospital referral region (HRR) level. RESULTS: Between 2014 and 2017, 2641 providers performed 308,247 procedures. The mean payment for OBL stent placement in 2017 was $4383.39, and mean payment for OBL atherectomy was $13,079.63. The change in the mean payment amount varied significantly, from a decrease of $16.97 in HRR 146 to an increase of $43.77 per beneficiary over the study period in HRR 11. The change in the rate of PVI also varied substantially, and moderately correlated with change in payment across HRRs (R2 = 0.40; P < .001). The majority of HRRs experienced an increase in rate of PVI within OBLs, which strongly correlated with changes in payments (R2 = 0.85; P < .001). Furthermore, 85% of the variance in change in payment was explained by increases in OBL atherectomy (P < .001). CONCLUSIONS: A rapid shift into the office setting for PVIs occurred within some HRRs, which was highly geographically variable and was strongly correlated with payments. Policymakers should revisit the current payment structure for OBL use and, in particular atherectomy, to better align the policy with its intended goals.

Natural variation for carotenoids in fresh kernels is controlled by uncommon variants in sweet corn.

Sweet corn (Zea mays L.) is highly consumed in the United States, but does not make major contributions to the daily intake of carotenoids (provitamin A carotenoids, lutein and zeaxanthin) that would help in the prevention of health complications. A genome-wide association study of seven kernel carotenoids and twelve derivative traits was conducted in a sweet corn inbred line association panel ranging from light to dark yellow in endosperm color to elucidate the genetic basis of carotenoid levels in fresh kernels. In agreement with earlier studies of maize kernels at maturity, we detected an association of ß-carotene hydroxylase (crtRB1) with ß-carotene concentration and lycopene epsilon cyclase (lcyE) with the ratio of flux between the α- and ß-carotene branches in the carotenoid biosynthetic pathway. Additionally, we found that 5% or less of the evaluated inbred lines possessing the shrunken2 (sh2) endosperm mutation had the most favorable lycE allele or crtRB1 haplotype for elevating ß-branch carotenoids (ß-carotene and zeaxanthin) or ß-carotene, respectively. Genomic prediction models with genome-wide markers obtained moderately high predictive abilities for the carotenoid traits, especially lutein, and outperformed models with less markers that targeted candidate genes implicated in the synthesis, retention, and/or genetic control of kernel carotenoids. Taken together, our results constitute an important step toward increasing carotenoids in fresh sweet corn kernels.

Barriers and Facilitators to De-Implementation of the Choosing Wisely® Guidelines for Low-Value Breast Cancer Surgery.

BACKGROUND: To address overuse of unnecessary practices, several surgical organizations have participated in the Choosing Wisely® campaign and identified four breast cancer surgical procedures as unnecessary. Despite evidence demonstrating no survival benefit for all four, evidence suggests only two have been substantially de-implemented. Our objective was to understand why surgeons stop performing certain unnecessary cancer operations but not others and how best to de-implement entrenched and emerging unnecessary procedures. METHODS: We sampled surgeons who treat breast cancer in a variety of practice types and geographic regions in the United States. Using a semi-structured guide, we conducted telephone interviews (n = 18) to elicit attitudes and understand practices relating to the four identified breast cancer procedures in the Choosing Wisely® campaign. Interviews were recorded, transcribed, and anonymized. Transcripts were analyzed using inductive and deductive thematic analysis. RESULTS: For the two procedures successfully de-implemented, surgeons described a high level of confidence in the data supporting the recommendations. In contrast, surgeons frequently described a lack of familiarity or skepticism toward the recommendation to avoid sentinel-node biopsy in women ≥ 70 years of age and the influence of other collaborating oncology providers as justification for continued use. Regarding contralateral prophylactic mastectomy, surgeons consistently agreed with the recommendation that this was unnecessary, yet reported continued utilization due to the value placed on patient autonomy and preference. CONCLUSIONS: With a growing focus on the elimination of ineffective, unproven or low value practices, it is imperative that the behavioral determinants are understood and targeted with specific interventions to decrease utilization rapidly.

The decline of open abdominal aortic aneurysm surgery among individual training programs and vascular surgery trainees.

OBJECTIVE: In the past decade, treatment of abdominal aortic aneurysm (AAA) has dramatically shifted from open repair to an endovascular approach. The decreasing number of open AAA repairs (OAR) has raised concerns regarding future vascular surgeons' competence to perform this complex and high-risk procedure. Prior work has documented decreasing open aortic volume among surgical residents. However, these studies report average national case volume with a limited understanding of the variation in OAR exposure among training programs and trainees. We sought to evaluate the current open AAA repair trends among individual accredited vascular surgery training programs and vascular surgery residents to better evaluate trainees' exposure to OAR. METHODS: We identified elderly Medicare beneficiaries undergoing OAR and endovascular aneurysm repair (EVAR) between 2010 and 2014. Accredited vascular surgery training program hospitals were identified. OAR and EVAR volume was aggregated at the program level and the number of senior vascular surgery trainees per year at each program was captured. The training program all-payer total AAA repair volume was calculated based on the national proportion of patients undergoing AAA covered by Medicare in the Vascular Quality Initiative. Temporal trends in program and vascular surgery trainee OAR and EVAR volume were calculated. RESULTS: A total of 119,408 (77%) EVAR and 35,042 (23%) were identified in the Medicare database between 2010 and 2014. Of these, 21% were performed among the 111 training programs, including 22,227 (73%) EVAR and 8416 (27%) OAR. The total OAR volume among training programs decreased by 38% during the study period, from a median of 29.1 to 18.2 OAR. In 2014, 25% of programs performed fewer than 10 OARs annually. Among senior vascular surgery trainees, the median number of OAR decreased from 10.0 in 2010 to 6.4 in 2014 and approximately one-half of senior trainees had exposure to fewer than five OAR in 2014. CONCLUSIONS: Exposure to OAR among vascular surgery training programs has dramatically decreased, with nearly one-half of senior trainees performing fewer than five OAR in 2014. The variable and diminishing OAR exposure among vascular surgery training program highlights growing concerns surrounding competence in complex open repairs and suggest that only a small proportion of current trainees have ample opportunity to develop confidence and proficiency in this high-risk operation.

Local Referral of High-risk Patients to High-quality Hospitals: Surgical Outcomes, Cost Savings, and Travel Burdens.

OBJECTIVE: We sought to assess the potential changes in Medicare payments and clinical outcomes of referring high-risk surgical patients to local high-quality hospitals within small geographic areas. SUMMARY BACKGROUND DATA: Previous studies have documented a benefit in referring high-risk patients to high-quality hospitals on a national basis, suggesting selective referral as a mechanism to improve the value of surgical care. Practically, referral of patients should be done within small geographic regions; however, the benefit of local selective referral has not been studied. METHODS: We analyzed data on elderly Medicare beneficiaries undergoing any of 4 elective inpatient surgical procedures between 2012 and 2014. Hospitals were categorized into Metropolitan Statistical Areas by zip code and stratified into quintiles of quality based on rates of postoperative complications. Patient risk was calculated by modeling the predicted risk of a postoperative complication. Medicare payments for each surgical episode were calculated. Distances between patients' home zip code and high- and low-quality hospitals were calculated. RESULTS: One quarter of high-risk patients underwent surgery at a low-quality hospital despite the availability of a high-quality hospital in their small geographic area. Shifting these patients to a local high-quality hospital would decrease spending 12% to 37% ($2,500 for total knee and hip replacement, $6,700 for colectomy, and $11,400 for lung resection). Approximately 45% of high-risk patients treated at low-quality hospitals could travel a shorter distance to reach a high-quality hospital than the low-quality hospital they received care at. CONCLUSIONS: Complication rates and Medicare payments are significantly lower for high-risk patients treated at local high-quality hospitals. This suggests triaging high-risk patients to local high-quality hospitals within small geographic areas may serve as a template for improving the value of surgical care.

Local Referral of High-Risk Pancreatectomy Patients to Improve Surgical Outcomes and Minimize Travel Burden.

BACKGROUND: Referring patients to high-quality hospitals for complex procedures may improve outcomes. This is most feasible within small geographic areas. However, access to specialized surgical procedures may be an implementation barrier. We sought to determine the availability of high-quality hospitals performing pancreatectomy and the potential benefit and travel burden of referral within small geographic areas. METHODS: We identified elderly Medicare beneficiaries undergoing pancreatectomy between 2012 and 2014. Hospitals were stratified into quintiles of quality based on postoperative complication rates. Patient risk was assessed by modeling the predicted risk of developing a postoperative complication. The geographic unit of analysis was Metropolitan Statistical Area (MSA). Hospitals were categorized into MSA by zip code. Travel distance was calculated using patient and hospital zip code. RESULTS: Among high-risk patients, 40.7% received care at the lowest-quality hospitals even though 80% had a high-quality hospital in the same MSA. Shifting these patients from low- to high-quality hospitals would decrease serious complications from 46.6 to 21.9% (P < 0.001) and mortality from 10.9 to 8.9% (P = 0.047). Three quarters of high-risk patients treated at low-quality hospitals could reach a high-quality hospital by extending their travel < 5 miles, and nearly 60% traveled farther to a low-quality hospital than was necessary to reach a high-quality hospital. CONCLUSIONS: High-risk pancreatectomy patients often receive care at low-quality hospitals despite the availability of high-quality hospitals in the area or within an acceptable distance. Referral of high-risk patients to high-quality hospitals within small geographic areas may be an effective strategy to improve outcomes following pancreatic surgery.

Variation in Hospital Door-to-Intervention Time for Ruptured AAAs and Its Association with Outcomes.

BACKGROUND: A ruptured abdominal aortic aneurysm (rAAA) is a life-threatening condition that carries a high mortality rate. Recent guidelines have recommended a goal "door-to-intervention" time of ≤90 minutes despite a paucity of evidence to support this goal. The aim of this study was to analyze recent trends in door-to-intervention time for rAAAs and determine the effect of the 90-minute door-to-intervention benchmark on postoperative complications. METHODS: A retrospective analysis of all patients who underwent open aortic repair (OAR) or endovascular aneurysm repair (EVAR) of a rAAA in the Vascular Quality Initiative database (2003-2018) was performed. Variation in door-to-intervention time was analyzed at the patient and hospital level. Patients were dichotomized into ≤90 or >90 minute door-to-intervention time cohorts. Hierarchical modeling controlling for the hospital random effect and multivariate logistic models was used to analyze the association on 30-day mortality and major in-hospital complications. RESULTS: A total of 3,630 operative cases for rAAA were identified (1696 OAR and 1934 EVAR). For the OAR cohort, 1035 patients (61%) had a door-to-intervention time of ≤90 minutes. However, at the hospital level, a minority of hospitals (49%) reliably achieved the OAR goal door-to-intervention time. For OARs, there was no difference in 30-day risk-adjusted major complications or mortality between the ≤90- and > 90-minute cohorts. For EVAR, 1014 patients (53.8%) had a door-to-intervention time of ≤90 minutes and a minority of hospitals (40%) upheld the recommended ≤90 minute door-to-intervention threshold. In the EVAR group, patients with a ≤90 minute door-to-intervention time had higher rates of postoperative myocardial infarction (12.0% vs. 8.5%; P < 0.05) but no difference in 30-day risk-adjusted mortality. CONCLUSIONS: A low percentage of rAAAs are being treated within the recommended door-to-intervention time. Despite this deficiency, the ≤90-minute benchmark has minimal impact on postoperative morbidity and mortality. Based on these findings, alternative quality metrics should be identified to improve the clinical care of patients with rAAA.

Volume Standards for Open Abdominal Aortic Aneurysm Repair Are Not Associated With Improved Clinical Outcomes.

BACKGROUND: Volume-outcome relationships exist for many complex surgical procedures, prompting institutions to adopt surgical volume standards for credentialing. The current Leapfrog Group Hospital volume standard for open abdominal aortic aneurysm repair (OAR) is 15 per year. However, this is primarily based on data from the 1990s and may not be appropriate given the dramatic decline in OAR. We sought to quantify the proportion of hospitals meeting volume standards, the difference in perioperative outcomes between low-volume and high-volume hospitals, and the potential travel burden of volume credentialing on patients. METHODS: We identified Medicare beneficiaries for individuals aged ≥65 years undergoing OAR in 2013-2014. Hospital "all-payer" annual volume was estimated based on the national proportion of patients undergoing OAR covered by Medicare in the Vascular Quality Initiative. Hospital annual OAR volume was characterized as <5/year, 5-9/year, 10-14/year, and ≥15/year (high volume). Adjusted rates of postoperative morbidity, reoperation, failure to rescue, and mortality in 2014 were compared across volume cohorts. Distance between patients' home zip code and high-volume hospitals was calculated. RESULTS: A total of 21,191 OARs were performed at 1,445 hospitals between 2013 and 2014. The average hospital OAR annual volume was 7.8 (standard deviation [SD] ± 9.3) with a median of 4.5. Among the 1,445 hospitals, only 190 (13.1%) performed ≥15 OARs per year whereas 756 hospitals (53.3%) performed <5 per year. Among patients who underwent OAR in 2014, 5,395 (53.3%) received care at a hospital that performed <15 per year. There was no difference in complication, reoperation, or failure to rescue rates between high-volume and low-volume hospitals. Mortality did not significantly differ among OAR volume cohorts. Hospitals performing <5 OARs per year had a mortality rate of 5.7% compared with 5.6% at high-volume hospitals (P = 0.817). One-quarter of patients who received care at a low-volume hospital would have had to travel more than 60 miles to reach a high-volume hospital. CONCLUSIONS: By conservative estimates, only 13% of hospitals performing OAR meet current volume standards. Triaging all patients to high-volume hospitals would require shifting over 5,000 patients annually with no associated improvement in perioperative outcomes. Implementation of the current OAR hospital volume standard may significantly burden patients and hospitals without improving surgical outcomes.

Financial impact of improving patient care setting selection after bariatric surgery.

BACKGROUND: Potentially avoidable emergency department (ED) visits are a significant source of excess healthcare spending. Despite improvement in postoperative readmissions, 20% of bariatric surgery patients use the ED postoperatively. Many of these visits may be appropriately managed in lower-acuity centers. OBJECTIVE: We sought to evaluate the economic impact of shifting potentially avoidable ED visits after bariatric surgery to lower-acuity centers. SETTING: Statewide quality improvement collaborative. METHODS: We performed an observational study of patients who underwent bariatric surgery between 2011 and 2017 using a linked data registry, including clinical data from a large-quality improvement collaborative and payment data from a statewide value collaborative. Postoperative ED visits and readmission rates were determined. Ninety-day ED and urgent care center (UCC) visit claims were matched to a clinical registry. Price-standardized payments for UCC and ED visits without admission were compared. RESULTS: Among the 36,071 patients who underwent bariatric surgery, 8.4% presented to the ED postoperatively. Approximately 50% of these visits resulted in readmission. Three hundred eighty-eight ED visits without readmission (i.e., potentially avoidable ED visits) and 110 UCC encounters with claims data were identified. Triaging a potentially avoidable ED visit to an UCC would generate a savings of $4238 per patient, reducing spending in this cohort by $1.6 million. CONCLUSION: Shifting potentially avoidable ED visits after bariatric surgery could result in significant cost savings. Efforts to improve patients' selection of healthcare setting and increase utilization of lower-acuity centers may serve as a template for appropriately meeting the needs of patients and containing spending after bariatric surgery.

Perioperative and 1-year outcomes of bariatric surgery in septuagenarians: implications for patient selection.

BACKGROUND: Although bariatric surgery is an effective treatment for obesity, utilization of bariatric procedures in older adults remains low. Previous work reported higher morbidity in older patients undergoing bariatric surgery. However, the generalizability of these data to contemporary septuagenarians is unclear. OBJECTIVES: We sought to evaluate differences in 30-day outcomes, 1-year weight loss, and co-morbidity remission after bariatric surgery among 3 age groups as follows: <45 years, 45-69 years, and ≥70 years. SETTING: Statewide quality improvement collaborative. METHODS: Using a large quality improvement collaborative, we identified patients undergoing sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB) between 2006 and 2018. We used multivariable logistic regression models to evaluate the association between age cohorts and 30-day outcomes, 1-year weight loss, and co-morbidity remission. RESULTS: We identified 641 septuagenarians who underwent SG (68.5%) or RYGB (31.5%). Compared with 45-69 year olds, septuagenarians had higher rates of hemorrhage (5.1% versus 3.1%; P = .045) after RYGB and higher rates of leak/perforation (.9% versus .3%; P = .044) after SG. Compared with younger patients, septuagenarians lost less of their excess weight, losing 64.8% after RYGB and 53.8% after SG. Remission rates for diabetes and obstructive sleep were similar for patients aged ≥70 years and 45-69 years. CONCLUSIONS: Bariatric surgery in septuagenarians results in substantial weight loss and co-morbidity remission with an acceptable safety profile. Surgeons with self-imposed age limits should consider broadening their selection criteria to include patients ≥70 years old.

Association of Discretionary Hospital Volume Standards for High-risk Cancer Surgery With Patient Outcomes and Access, 2005-2016.

Importance: Various clinical societies and patient advocacy organizations continue to encourage minimum volume standards at hospitals that perform certain high-risk operations. Although many clinicians and quality and safety experts believe this can improve outcomes, the extent to which hospitals have responded to these discretionary standards remains unclear. Objective: To evaluate the association between short-term clinical outcomes and hospitals' adherence to the Leapfrog Group's minimum volume standards for high-risk cancer surgery. Design, Setting, and Participants: Longitudinal cohort study using 100% of the Medicare claims for 516 392 patients undergoing pancreatic, esophageal, rectal, or lung resection for cancer between January 1, 2005, and December 31, 2016. Data were accessed between December 1, 2018, and April 30, 2019. Exposures: High-risk cancer surgery in hospitals meeting and not meeting the minimum volume standards. Main Outcomes and Measures: Patients having surgery in hospitals meeting the volume standard and 30-day and in-hospital mortality and complication rates. Results: Overall, a total of 516 392 procedures (47 318 pancreatic resections, 29 812 esophageal resections, 116 383 rectal resections, and 322 879 lung resections) were included in the study, and patient mean (SD) age was 73.1 (7.5) years. Outcomes improved over time in both hospitals meeting and not meeting the minimum volume standards. Mortality after pancreatic resection decreased from 5.5% in 2005 to 4.8% in 2016 (P for trend <.001). Mortality after esophageal resection decreased from in 6.7% 2005 to 5.0% in 2016 (P for trend <.001). Mortality after rectal resection decreased from 3.6% in 2005 to 2.7 % in 2016 (P for trend <.001). Mortality after lung resection decreased from 4.2% in 2005 to 2.7 % in 2016 (P for trend <.001). Throughout the study period, there were no statistically significant differences in risk-adjusted mortality between hospitals meeting and not meeting the volume standards for esophageal, lung, and rectal cancer resections. Mortality rates after pancreatic resection were consistently lower at hospitals meeting the volume standard, although mortality at all hospitals decreased over the study period. For example, in 2016, risk-adjusted mortality rates for hospitals meeting the volume standard were 3.8% (95% CI, 3.3%-4.3%) compared with 5.7% (95% CI, 5.1%-6.5%) for hospitals that did not. Although an increasing majority of patients underwent surgery in hospitals meeting the Leapfrog volume standards over time, the overall proportion of hospitals meeting the standards in 2016 ranged from 5.6% for esophageal resection to 23.3% for pancreatic resection. Conclusions and Relevance: Although volume remains an important factor for patient safety, the Leapfrog Group's minimum volume standards did not differentiate hospitals based on mortality for 3 of the 4 high-risk cancer operations assessed, and few hospitals were able to meet these standards. These findings highlight important tradeoffs between setting effective volume thresholds and practical expectations for hospital adherence and patient access to centers that meet those standards.

Genome-Wide Association and Genomic Prediction Models of Tocochromanols in Fresh Sweet Corn Kernels.

Sweet corn ( L.), a highly consumed fresh vegetable in the United States, varies for tocochromanol (tocopherol and tocotrienol) levels but makes only a limited contribution to daily intake of vitamin E and antioxidants. We performed a genome-wide association study of six tocochromanol compounds and 14 derivative traits across a sweet corn inbred line association panel to identify genes associated with natural variation for tocochromanols and vitamin E in fresh kernels. Concordant with prior studies in mature maize kernels, an association was detected between γ-tocopherol methyltransferase (vte4) and α-tocopherol content, along with () and () for tocotrienol variation. Additionally, two kernel starch synthesis genes, () and (), were associated with tocotrienols, with the strongest evidence for in combination with fixed, strong and alleles, accounting for the greater amount of tocotrienols in and lines. In prediction models with genome-wide markers, predictive abilities were higher for tocotrienols than tocopherols, and these models were superior to those that used marker sets targeting a priori genes involved in the biosynthesis and/or genetic control of tocochromanols. Through this quantitative genetic analysis, we have established a key step for increasing tocochromanols in fresh kernels of sweet corn for human health and nutrition.

Monitoring dendrimer conformational transition using 19 F and 1 H2 O NMR.

The conformational transition of a fluorinated amphiphilic dendrimer is monitored by the 1 H signal from water, alongside the 19 F signal from the dendrimer. High-field NMR data (chemical shift δ, self-diffusion coefficient D, longitudinal relaxation rate R1 , and transverse relaxation rate R2 ) for both dendrimer (19 F) and water (1 H) match each other in detecting the conformational transition. Among all parameters for both nuclei, the water proton transverse-relaxation rate R2 (1 H2 O) displays the highest relative scale of change upon conformational transition of the dendrimer. Hydrogen/deuterium-exchange mass spectrometry reveals that the compact form of the dendrimer has slower proton exchange with water than the extended form. This result suggests that the sensitivity of R2 (1 H2 O) toward dendrimer conformation originates, at least partially, from the difference in proton exchange efficiency between different dendrimer conformations. Finally, we also demonstrated that this conformational transition could be conveniently monitored using a low-field benchtop NMR spectrometer via R2 (1 H2 O). The 1 H2 O signal thus offers a simple way to monitor structural changes of macromolecules using benchtop time-domain NMR.