Esophageal Cancer Surgery: Spontaneous Centralization in the US Contributed to Reduce Mortality Without Causing Health Disparities

Background: Improvement in mortality has been shown for esophagectomies performed at high-volume centers. Objective: This study aimed to determine if centralization of esophageal cancer surgery occurred in the US, and to establish its impact on postoperative mortality. In addition, we aimed to analyze the relationship between regionalization of cancer care and health disparities. Methods: A retrospective population-based analysis was performed using the National Inpatient Sample for the period 2000–2014. Adult patients (≥ 18 years of age) diagnosed with esophageal cancer and who underwent esophagectomy were included. Yearly hospital volume was categorized as low ( 20 procedures). Multivariable analyses on the potential effect of hospital volume on patient outcomes were performed, and the yearly rate of esophagectomies was estimated using Poisson regression. Results: A total of 5235 patients were included. Esophagectomy at low- [odds ratio (OR) 2.17] and intermediate-volume (OR 1.62) hospitals, compared with high-volume hospitals, was associated with a significant increase in mortality. The percentage of esophagectomies performed at high-volume centers significantly increased during the study period (29.2–68.5%; p < 0.0001). The trend towards high-volume hospitals was different among the different US regions: South (7.7–54.3%), West (15.0–67.6%), Midwest (37.3–67.7%), and Northeast (55.8–86.8%) [p < 0.0001]. Overall, the mortality rate of esophagectomy dropped from 10.0 to 3.5% (p = 0.006), with non-White race, public insurance, and low household income patients also showing a significant reduction in mortality. Conclusions: A spontaneous centralization for esophageal cancer surgery occurred in the US. This process was associated with a decrease in the mortality rate, without contributing to health disparities

The relative contributions of myocardial wall thickness and ischemia to ultrasonic myocardial integrated backscatter during experimental ischemia

Abstract The purpose of this study was to assess the empirical relationship between myocardial integrated backscatter (IB) and myocardial wall thickness (WT) in normal myocardium. A second object was to estimate the additional contribution to acute ischemic integrated backscatter levels given this relationship. Myocardial IB measurements and simultaneous myocardial WT measurements were made in 16 open-chested pigs with intact coronary circulation (normal myocardium) and 10 min after the flow in the left anterior descending coronary artery had been reduced to 20% of its baseline value (ischemic myocardium). Measurements were made 50 times during one cardiac cycle and averaged over 10 cardiac cycles. IB and WT measurements were normalized with respect to the nonischemic end-diastolic values. The relationship between IB and WT in normal myocardium was estimated in every individual pig by simple linear regression. Estimates of IB during ischemia were calculated on the basis of this relationship and the ischemic WT measurements. Differences of the estimator and the actual measurement made during ischemia depict the actual contribution of the state of acute ischemia, without the influence of WT. The slope of the relationship between IB and WT during normal myocardial contraction ranged from −0.16 to 0.03 dB/% (mean = −0.036 dB/%, SD = 0.06 dB/%). The additional contribution of ischemia ranged from −3.84 to 5.56 dB (mean = 0.31 dB, SD = 2.72 dB). It was concluded that the average contribution of ischemia to IB measurements is insignificant if the IB dependency on WT is removed from the data and that the higher level of ischemic IB measurements can be explained by the decrease in wall thickness during ischemia and not by the ischemia itself

Cholecystectomy Vs. Cholecystostomy for the Management of Acute Cholecystitis in Elderly Patients

Background: Data comparing outcomes following cholecystectomy and cholecystostomy tube placement (CTP) in elderly patients are lacking. We aimed to compare the post-procedural outcomes between cholecystectomy and CTP in elderly patients with acute cholecystitis. Methods: We performed a retrospective, population-based analysis using the National Inpatient Sample for the period 2000–2014. Patients ≥ 65 years old admitted with a primary diagnosis of acute cholecystitis and who underwent either cholecystectomy or CTP during their hospitalization were included. Multivariable linear and logistic regression models were used to analyze post-procedural complications, mortality, length of stay, and total charges. The effect of procedure type on patient outcomes, stratified by acalculous and calculous cholecystitis, was also performed. Results: A total of 200,915 patients were included, of which 7516 underwent CTP and 193,399 underwent cholecystectomy. The median age of patients undergoing CTP and cholecystectomy was 80 (IQR 73–87) and 75 (IQR 70–81), respectively. Patients undergoing CTP were more likely to have post-procedural infection (OR 2.25; 95% CI 2.07, 2.45), bleeding (OR 1.28; 95% CI 1.19, 1.37), and inpatient mortality (OR 9.27; 95% CI 7.95, 10.81). On average, CTP patients stayed 1.25 days longer (95% CI 1.14, 1.37) in hospital after the procedure. The benefits of cholecystectomy were consistent in patients with acalculous and calculous cholecystitis. Conclusions: Elderly patients with both acalculous and calculous acute cholecystitis managed with CTP have higher incidences of post-procedural morbidity and mortality, and longer post-procedure length of hospital stay, as compared to cholecystectomy. Unless prohibitive surgical risks exist, elderly patients with acute cholecystitis should undergo cholecystectomy

Health care disparities in colorectal and esophageal cancer

Background: We aimed to identify differences in disparities among patients with a cancer in which screening is widely recommended (colorectal cancer [CRC]) and one in which it is not (esophageal cancer). Methods: A retrospective analysis was performed using 2004–2015 data from the National Cancer Database. Multivariable generalized logistic regression was used to identify potential differences in the effect of disparities in stage at diagnosis. Results: A total of 96,524 esophageal cancer patients and 361,187 CRC patients were included. Black patients, longer travel distances, and lower educational attainment were only associated with increased odds of stage IV CRC. While both Medicaid and uninsured patients were more likely to be diagnosed with stage IV esophageal and CRC, the effect was larger among CRC patients. From 2004 to 2015, the rates of stage IV esophageal cancer decreased from 42.0% to 38.2%, while the rates of stage IV CRC increased from 36.9% to 40.8% (p < 0.0001). Conclusions: Disparities are more pronounced in CRC, compared to esophageal cancer. Equity in access to screening and cancer care should be prioritized

Two-Dimensional Critical Percolation: The Full Scaling Limit

We use SLE(6) paths to construct a process of continuum nonsimple loops in the plane and prove that this process coincides with the full continuum scaling limit of 2D critical site percolation on the triangular lattice -- that is, the scaling limit of the set of all interfaces between different clusters. Some properties of the loop process, including conformal invariance, are also proved.Comment: 45 pages, 12 figures. This is a revised version of math.PR/0504036 without the appendice

Anatomic Location and Mechanism of Injury Correlating with Prehospital Deaths in Sub-Saharan Africa

Introduction: Trauma is a large contributor to morbidity and mortality in developing countries. We sought to determine which anatomic injury locations and mechanisms of injury predispose to prehospital mortality in Malawi to help target preventive and therapeutic interventions. We hypothesized that head injury would result in the highest prehospital mortality. Methods: This was a retrospective analysis of all trauma patients presenting to Kamuzu Central Hospital in Lilongwe, Malawi, from 2008 to 2015. Independent variables included baseline characteristics, anatomic location of primary injury, mechanism of injury, and severity of secondary injuries. Multivariable logistic regression was used to assess the effect of primary injury location and injury mechanism on prehospital death, after adjusting for confounders. Effect measure modification of the primary injury site/prehospital death relationship by injury mechanism (stratified into intentional and unintentional injury) was assessed. Results: Of 85,806 patients, 701 died in transit (0.8%). Five hundred and five (72%) of these patients sustained a primary head injury. After adjustment, head injury was the anatomic location most associated with prehospital death (OR 11.81 (95% CI 6.96–20.06, p < 0.0001). The mechanisms of injury most associated with prehospital death were gunshot wounds (OR 38.23, 95% CI 17.66–87.78, p < 0.0001) and pedestrian hit by vehicle (OR 2.62, 95% CI 1.92–3.55, p < 0.0001). Among head injury patients, the odds of prehospital mortality were higher with unintentional injuries. Conclusions: Head injuries are the most common causes of prehospital death in Malawi, while pedestrians hit by vehicles are the most common mechanisms. In a resource-poor setting, preventive measures are critical in averting mortality

Curved Tails in Polymerization-Based Bacterial Motility

The curved actin ``comet-tail'' of the bacterium Listeria monocytogenes is a visually striking signature of actin polymerization-based motility. Similar actin tails are associated with Shigella flexneri, spotted-fever Rickettsiae, the Vaccinia virus, and vesicles and microspheres in related in vitro systems. We show that the torque required to produce the curvature in the tail can arise from randomly placed actin filaments pushing the bacterium or particle. We find that the curvature magnitude determines the number of actively pushing filaments, independent of viscosity and of the molecular details of force generation. The variation of the curvature with time can be used to infer the dynamics of actin filaments at the bacterial surface.Comment: 8 pages, 2 figures, Latex2