Does A Diagnostic Algorithm Reduce the Overuse of Chest CT Angiography in Suspected Pulmonary Embolism? : A Pre- and Post-Intervention Retrospective Study in a Critical Access Hospital

Background: Pulmonary embolism (PE) is a common and potentially fatal disease. Although CTA is a gold standard for diagnosis, it carries risks for patients. We sought to minimize the overutilization of chest CTA by implementing a diagnostic algorithm in the hospital to evaluate the likelihood of PE and determine the need for imaging with CTA. Methods: A retrospective medical chart review was performed for all patients suspicious of PE at Redington-Fairview General Hospital 3 months before and after diagnostic algorithm implementation. Patients who underwent either D-dimer testing or chest CTA were included. Patients were excluded if d-dimer testing was performed for suspected deep vein thrombosis (DVT) alone or chest CTA was performed for other reasons. Patients were divided into 3 categories of probability according to their Wells scores. The algorithms from the American College of Physicians (ACP) were used to determine the next step of management. Results: A total of 414 patients were included in our study, 236 (57%) patients in 2017 and 178 (43%) patients in 2018. The mean age was 51 years (SD=19.17). A total of 168 CTAs were performed and found that 11 patients (15%) had PEs. There was a significant increase in the ordering of D-dimer levels after the diagnostic algorithm had been implemented (80.9% vs 89.3%, p=0.019), particularly in the low probability group. The use of D-dimer increased among patients in the low probability group who met PERC criteria (80.3% vs 97.17%, p=0.001). We observed an 11% reduction in the CTAs ordered in the post-intervention group compared to the pre-intervention group (45.3% vs 34.3%, p=0.023). Conclusion: Our study found that the implementation of a diagnostic algorithm for PE led to a significant reduction in the use of CTA

Uniformity in association schemes and coherent configurations: cometric Q-antipodal schemes and linked systems

Inspired by some intriguing examples, we study uniform association schemes and uniform coherent configurations, including cometric Q-antipodal association schemes. After a review of imprimitivity, we show that an imprimitive association scheme is uniform if and only if it is dismantlable, and we cast these schemes in the broader context of certain --- uniform --- coherent configurations. We also give a third characterization of uniform schemes in terms of the Krein parameters, and derive information on the primitive idempotents of such a scheme. In the second half of the paper, we apply these results to cometric association schemes. We show that each such scheme is uniform if and only if it is Q-antipodal, and derive results on the parameters of the subschemes and dismantled schemes of cometric Q-antipodal schemes. We revisit the correspondence between uniform indecomposable three-class schemes and linked systems of symmetric designs, and show that these are cometric Q-antipodal. We obtain a characterization of cometric Q-antipodal four-class schemes in terms of only a few parameters, and show that any strongly regular graph with a ("non-exceptional") strongly regular decomposition gives rise to such a scheme. Hemisystems in generalized quadrangles provide interesting examples of such decompositions. We finish with a short discussion of five-class schemes as well as a list of all feasible parameter sets for cometric Q-antipodal four-class schemes with at most six fibres and fibre size at most 2000, and describe the known examples. Most of these examples are related to groups, codes, and geometries.Comment: 42 pages, 1 figure, 1 table. Published version, minor revisions, April 201

Prediction of craniofacial growth: The state of the art

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33743/1/0000259.pd

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Does A Diagnostic Algorithm Reduce the Overuse of Chest CT Angiography in Suspected Pulmonary Embolism? : A Pre- and Post-Intervention Retrospective Study in a Critical Access Hospital

Background: Pulmonary embolism (PE) is a common and potentially fatal disease. Although CTA is a gold standard for diagnosis, it carries risks for patients. We sought to minimize the overutilization of chest CTA by implementing a diagnostic algorithm in the hospital to evaluate the likelihood of PE and determine the need for imaging with CTA. Methods: A retrospective medical chart review was performed for all patients suspicious of PE at Redington-Fairview General Hospital 3 months before and after diagnostic algorithm implementation. Patients who underwent either D-dimer testing or chest CTA were included. Patients were excluded if d-dimer testing was performed for suspected deep vein thrombosis (DVT) alone or chest CTA was performed for other reasons. Patients were divided into 3 categories of probability according to their Wells scores. The algorithms from the American College of Physicians (ACP) were used to determine the next step of management. Results: A total of 414 patients were included in our study, 236 (57%) patients in 2017 and 178 (43%) patients in 2018. The mean age was 51 years (SD=19.17). A total of 168 CTAs were performed and found that 11 patients (15%) had PEs. There was a significant increase in the ordering of D-dimer levels after the diagnostic algorithm had been implemented (80.9% vs 89.3%, p=0.019), particularly in the low probability group. The use of D-dimer increased among patients in the low probability group who met PERC criteria (80.3% vs 97.17%, p=0.001). We observed an 11% reduction in the CTAs ordered in the post-intervention group compared to the pre-intervention group (45.3% vs 34.3%, p=0.023). Conclusion: Our study found that the implementation of a diagnostic algorithm for PE led to a significant reduction in the use of CTA