Design principles for the use of simulation as an aid in interventional cardiology training

Learning complex skills through simulation is a goal for training physicians in specialties such as interventional cardiology, where traditional training puts patients at risk. Intuitively, interactive simulation of anatomy, pathology and therapeutic actions should lead to shortening of the learning curve for novice or inexperienced physicians. An accurate recreation of the interactions among anatomy, pathology and therapeutic actions is a necessary, but not sufficient, condition for the development of a simulation-based training system. In addition to real-time graphic interactivity coupled with haptic response, a successful training tool will require features of a 'learning system' such as: an embedded curriculum, functionality that allows rehearsal and practice, hypertext links to educational information, personal archiving, and instructor review and testing capabilities. We describe how such a system might look for the field of interventional cardiology, and suggest that designing a simulation with both technical and pedagogical fidelity is essential in developing simulation-based training systems in any field of medicine.     

The natural history and significance of ultrasonographically defined polypoid lesions of the gallbladder in children

Background/Purpose

Gallbladder polyps are relatively common in adults and may increase the risk of gallbladder cancer. The increased use of high-quality abdominal ultrasonography has likely led to the increase detection of these lesions in the pediatric population. The aim of the present study was to address the significance of the ultrasonographic finding of a gallbladder polyp in children.

Methods

This prospective case series of 4 children with ultrasonographically defined gallbladder polyps outlines their presentation and clinical course. A detailed review of the literature and a management approach has been provided.

Results

In the 4 cases, polyps were followed for 2, 5, 72, and 84 months with a clinical follow-up of 7 to 11 years. Three underwent cholecystectomy and only 1 of 3 had a polypoid gallbladder lesion. One child, followed for 7 years, had no change in size, shape, or location of the polyp. This case series adds to the small group of children in the literature with polypoid gallbladder lesions and, to our knowledge, none have developed malignant transformation.

Conclusions

Clearly more studies on such children are required to further add to our knowledge on the natural history and the appropriate management of these lesions.     

Interpreting a rising prostate‐specific antigen after brachytherapy for prostate cancer

The aim of the present study was to review the English language literature on the topic of prostate‐specific antigen bounce after brachytherapy and present a summary of the current knowledge. Although ultimately prostate‐specific antigen is a reliable measure of success after prostate brachytherapy, it can be very misleading in the first 3 years because of the frequency with which temporary benign rises in prostate‐specific antigen occur. We have reviewed the English language literature on the topic of prostate‐specific antigen bounce under the following headings: prostate neoplasms, brachytherapy, biochemical definition of prostate‐specific antigen failure, “benign prostate‐specific antigen bounce” and “prostate‐specific antigen spike”. We included brachytherapy delivered as either low dose rate or high dose rate, and either as monotherapy or as a boost combined with external beam radiotherapy. A benign self‐limited rise in prostate‐specific antigen after prostate brachytherapy is seen in an average of 35% of patients, but increases in frequency with younger age. In patients aged less than 55 years, it is observed in up to 68%. Other factors, such as sexual activity, dose, prostate volume and the use of high dose rate versus low dose rate have been implicated in affecting the frequency of the benign bounce. Benign increases in prostate‐specific antigen are frequent after prostate brachytherapy. It is important to recognize and correctly diagnose this phenomenon in order to avoid unnecessary salvage treatment.     

Developmental alterations in pulmonary function of the lamb

Pulmonary function was evaluated in 40 lambs ranging in age from 106 to 161 postconceptual days. Preterm lambs were delivered by cesarean section and newborn lambs were delivered vaginally. All animals were mechanically ventilated and had indwelling catheters. Measurements of transpulmonary pressure, airflow, tidal volume and functional residual capacity enabled calculations of lung compliance, specific compliance, lung conductance and specific conductance. Regression analysis indicated that lung compliance, lung conductance and functional residual capacity increased with developmental age; whereas, specific compliance and specific conductance decreased with maturity. These data quantitate the developmental alterations in the pulmonary function of preterm, term and newborn lambs.     

Efficacy and Safety of Everolimus Plus Low‐Dose Tacrolimus Versus Mycophenolate Mofetil Plus Standard‐Dose Tacrolimus in De Novo Renal Transplant Recipients: 12‐Month Data

In this 12‐month, multicenter, randomized, open‐label, noninferiority study, de novo renal transplant recipients (RTxRs) were randomized (1:1) to receive everolimus plus low‐dose tacrolimus (EVR+LTac) or mycophenolate mofetil plus standard‐dose Tac (MMF+STac) with induction therapy (basiliximab or rabbit anti‐thymocyte globulin). Noninferiority of composite efficacy failure rate (treated biopsy‐proven acute rejection [tBPAR]/graft loss/death/loss to follow‐up) in EVR+LTac versus MMF+STac was missed by 1.4%, considering the noninferiority margin of 10% (24.6% vs. 20.4%; 4.2% [?3.0, 11.4]). Incidence of tBPAR (19.1% vs. 11.2%; p < 0.05) was significantly higher, while graft loss (1.3% vs. 3.9%; p < 0.05) and composite of graft loss/death/lost to follow‐up (6.1% vs. 10.5%, p = 0.05) were significantly lower in EVR+LTac versus MMF+STac groups, respectively. Mean estimated glomerular filtration rate was similar between EVR+LTac and MMF+STac groups (63.1 [22.0] vs. 63.1 [19.5] mL/min/1.73 m²) and safety was comparable. In conclusion, EVR+LTac missed noninferiority versus MMF+STac based on the 10% noninferiority margin. Further studies evaluating optimal immunosuppression for improved efficacy will guide appropriate dosing and target levels of EVR and LTac in RTxRs.     

Radiotherapy for benign disease; assessing the risk of radiation-induced cancer following exposure to intermediate dose radiation

Most radiotherapy (RT) involves the use of high doses (>50 Gy) to treat malignant disease. However, low to intermediate doses (approximately 3–50 Gy) can provide effective control of a number of benign conditions, ranging from inflammatory/proliferative disorders (e.g. Dupuytren''s disease, heterotopic ossification, keloid scarring, pigmented villonodular synovitis) to benign tumours (e.g. glomus tumours or juvenile nasopharyngeal angiofibromas). Current use in UK RT departments is very variable. This review identifies those benign diseases for which RT provides good control of symptoms with, for the most part, minimal side effects. However, exposure to radiation has the potential to cause a radiation-induced cancer (RIC) many years after treatment. The evidence for the magnitude of this risk comes from many disparate sources and is constrained by the small number of long-term studies in relevant clinical cohorts. This review considers the types of evidence available, i.e. theoretical models, phantom studies, epidemiological studies, long-term follow-up of cancer patients and those treated for benign disease, although many of the latter data pertain to treatments that are no longer used. Informative studies are summarized and considered in relation to the potential for development of a RIC in a range of key tissues (skin, brain etc.). Overall, the evidence suggests that the risks of cancer following RT for benign disease for currently advised protocols are small, especially in older patients. However, the balance of risk vs benefit needs to be considered in younger adults and especially if RT is being considered in adolescents or children.     

Spondylolysis and spondylolisthesis in the athlete

Though athletes may be able to return to their sport after treatment of spondylolysis and spondylolisthesis, prevention of back injury in at-risk patient athletes should be the treating physician's primary goal.     

Analyzing treatment aggressiveness and identifying high‐risk patients in diabetic foot ulcer return to care

Rates of diabetes and its associated comorbidities have been increasing in the United States, with diabetic foot ulcer treatment representing a large cost to the patient and healthcare system. These ulcers often result in multiple hospital admissions. This study examined readmissions following inpatient care for a diabetic foot ulcer and identified modifiable factors associated with all‐cause 30‐day readmissions to the inpatient or emergency department (ED) setting. We hypothesized that patients undergoing aggressive treatment would have lower 30‐day readmission rates. We identified patient discharge records containing International Classification of Disease ninth revision codes for both diabetes mellitus and distal foot ulcer in the State Inpatient and Emergency Department databases from the Agency for Healthcare Research and Quality, Healthcare Cost and Utilization Project in Florida and New York, 2011–2012. All‐cause 30‐day return to care visits (ED or inpatient) were analyzed. Patient demographics and treatment characteristics were evaluated using univariate and multivariable regression models. The cohort included 25,911 discharges, having a mean age of 63 and an average of 3.8 comorbidities. The overall rate of return to care was 30%, and 21% of subjects underwent a toe or midfoot amputation during their index stay. The most common diagnosis codes upon readmission were diabetes mellitus (19%) and infection (13%). Patients with a toe or midfoot amputation procedure were less likely to be readmitted within 30 days (odds ratio: 0.78; 95% confidence interval: 0.73, 0.84). Presence of comorbidities, black and Hispanic ethnicities, and Medicare and Medicaid payer status were also associated with higher odds of readmission following initial hospitalization (p < 0.05). The study suggests that there are many factors that affect readmission rates for diabetic foot ulcer patients. Understanding patients at high‐risk for readmission can improve counseling and treatment strategies for this fragile patient population.     

Differential Ly6C Expression after Renal Ischemia-Reperfusion Identifies Unique Macrophage Populations

Macrophages are a heterogeneous cell type implicated in injury, repair, and fibrosis after AKI, but the macrophage population associated with each phase is unclear. In this study, we used a renal bilateral ischemia-reperfusion injury mouse model to identify unique monocyte/macrophage populations by differential expression of Ly6C in CD11b⁺ cells and to define the function of these cells in the pathophysiology of disease on the basis of microarray gene signatures and reduction strategies. Macrophage populations were isolated from kidney homogenates by fluorescence-activated cell sorting for whole genome microarray analysis. The CD11b⁺/Ly6C^high population associated with the onset of renal injury and increase in proinflammatory cytokines, whereas the CD11b⁺/Ly6C^intermediate population peaked during kidney repair. The CD11b⁺/Ly6C^low population emerged with developing renal fibrosis. Principal component and hierarchical cluster analyses identified gene signatures unique to each population. The CD11b⁺/Ly6C^intermediate population had a distinct phenotype of wound healing, confirmed by results of studies inhibiting the macrophage colony-stimulating factor 1 receptor,whereas the CD11b⁺/Ly6C^low population had a profibrotic phenotype. All populations, including the CD11b⁺/Ly6C^high population, carried differential inflammatory signatures. The expression of M2-specific markers was detected in both the CD11b⁺/Ly6C^intermediate and CD11b⁺/Ly6C^low populations, suggesting these in vivo populations do not fit into the traditional classifications defined by in vitro systems. Results of this study in a renal ischemia-reperfusion injury model allow phenotype and function to be assigned to CD11b⁺/Ly6C⁺ monocyte/macrophage populations in the pathophysiology of disease after AKI.