Evaluation of the Canadian Clinical Practice Guidelines Risk Prediction Tool for Acute Aortic Syndrome: The RIPP Score.

Introduction: Acute aortic syndrome (AAS) is a rare clinical syndrome with a high mortality rate. The Canadian clinical practice guideline for the diagnosis of AAS was developed in order to reduce the frequency of misdiagnoses. As part of the guideline, a clinical decision aid was developed to facilitate clinician decision-making (RIPP score). The aim of this study is to validate the diagnostic accuracy of this tool and assess its performance in comparison to other risk prediction tools that have been developed. Methods: This was a historical case-control study. Consecutive cases and controls were recruited from three academic emergency departments from 2002-2020. Cases were identified through an admission, discharge, or death certificated diagnosis of acute aortic syndrome. Controls were identified through presenting complaint of chest, abdominal, flank, back pain, and/or perfusion deficit. We compared the clinical decision tools' C statistic and used the DeLong method to test for the significance of these differences and report sensitivity and specificity with 95% confidence intervals. Results: We collected data on 379 cases of acute aortic syndrome and 1340 potential eligible controls; 379 patients were randomly selected from the final population. The RIPP score had a sensitivity of 99.7% (98.54-99.99). This higher sensitivity resulted in a lower specificity (53%) compared to the other clinical decision aids (63-86%). The DeLong comparison of the C statistics found that the RIPP score had a higher C statistic than the ADDRS (-0.0423 (95% confidence interval -0.07-0.02); P < 0.0009) and the AORTAs score (-0.05 (-0.07 to -0.02); P = 0.0002), no difference compared to the Lovy decision tool (0.02 (95% CI -0.01-0.05 P < 0.25)) and decreased compared to the Von Kodolitsch decision tool (0.04 (95% CI 0.01-0.07 P < 0.008)). Conclusion: The Canadian clinical practice guideline's AAS clinical decision aid is a highly sensitive tool that uses readily available clinical information. It has the potential to improve diagnosis of AAS in the emergency department.

Does implementation of a diagnostic pathway for acute aortic syndrome including D-dimer increase the usage of D-dimer and computed tomography?

INTRODUCTION: The Canadian clinical practice guidelines propose a novel diagnostic pathway incorporating a clinical decision tool and D-dimer to aid in risk stratifying patients for acute aortic syndrome. The objective of this study was to assess if implementation of a diagnostic pathway incorporating D-dimer would increase the usage of D-dimer and computed tomography (CT) in a tertiary care emergency department. METHODS: Prospective single centre before and after study-recruiting patients over a 6-week period from a tertiary care emergency department. INTERVENTION: multi model implementation of a diagnostic pathway for acute aortic syndrome incorporating D-dimer. OUTCOME: proportion of patients receiving D-dimer testing/CT in the 2 weeks before and after implementation. RESULTS: We included 982 patients (Female 55%, Age mean 51.9, N = 492 pre intervention and N = 490 post intervention). The proportion that received a D-dimer test increased from 6.9 to 10.4% (p < 0.051), while the number of CT aortas remained stable (0.6% vs. 0.6%; p = 0.60). Documentation of pretest probability assessment increased from 1 to 3%, (p < 0.009) following the intervention. In the post intervention cohort, the tool was applied correctly in all cases (N = 17). CONCLUSION: This single centre study found that a diagnostic pathway for acute aortic syndrome including D-dimer could be implemented without a significant increase in test ordering during this first 2 weeks after implementation. This study adds to the argument for use of D-dimer to help risk stratify patients for the diagnosis of acute aortic syndrome. Future studies are needed to confirm the diagnostic accuracy of this pathway and the long-term impact on resource utilization.

RéSUMé: INTRODUCTION: Les guides de pratique clinique canadiens proposent une nouvelle voie de diagnostic intégrant un outil de décision clinique et du D-dimère pour aider à stratifier le risque chez les patients atteints du syndrome aortique aigu. L'objectif de cette étude était d'évaluer si la mise en place d'une voie diagnostique intégrant le dimère-D augmenterait l'utilisation du dimère-D et de la tomodensitométrie (TDM) dans un service d'urgence de soins tertiaires. MéTHODES: Centre unique prospectif avant et après l'étude - recrutement de patients sur une période de 6 semaines à partir d'un service d'urgence de soins tertiaires. Intervention : mise en œuvre multi-modèle d'une voie diagnostique pour le syndrome aortique aigu intégrant le D-dimère. Résultat : Proportion de patients ayant subi un test des D-dimères/TDM dans les deux semaines précédant et suivant la mise en œuvre. RéSULTATS: Nous avons inclus 982 patients (femmes 55 %, âge moyen 51,9, N = 492 avant l'intervention et N = 490 après l'intervention). La proportion de personnes ayant reçu un test D-dimère est passée de 6,9 % à 10,4 % (p < 0,051), tandis que le nombre d'aortes CT est demeuré stable (0,6 % contre 0,6 %; p = 0,60). La documentation de l'évaluation de la probabilité avant le test est passée de 1 % à 3 % (p<0,009) après l'intervention. Dans la cohorte post-intervention, l'outil a été appliqué correctement dans tous les cas (n = 17). CONCLUSION: Cette étude menée auprès d'un seul centre a révélé qu'une voie diagnostique pour le syndrome aortique aigu, y compris le D-dimère, pourrait être mise en œuvre sans qu'il y ait une augmentation significative de l'ordre des tests au cours des deux premières semaines suivant la mise en œuvre. Cette étude renforce l'argument en faveur de l'utilisation du D-dimère pour aider à stratifier les risques des patients pour le diagnostic du syndrome aortique aigu. De futures études sont nécessaires pour confirmer la précision du diagnostic de cette voie et l'impact à long terme sur l'utilisation des ressources.

The use and misuse of the Dix-Hallpike test in the emergency department.

OBJECTIVES: A simple bedside test, the Dix-Hallpike test (DHT), can reliably diagnose benign paroxysmal positional vertigo (BPPV) in patients with acute onset dizziness or vertigo. We evaluated patterns of DHT use by emergency physicians in patients presenting with dizziness and vertigo. Our objective was to assess the frequency and clinically appropriate use of the DHT in an emergency department. METHODS: A health records review was performed using data from patients who presented to a tertiary care emergency department between September 2014 and March 2018 with a primary complaint of vertigo or dizziness. Patient records were reviewed for documentation of symptoms consistent with BPPV and DHT usage. RESULTS: A total of 2309 patients met inclusion criteria. Of all dizzy patients who had complete documentation of signs and symptoms consistent with BPPV, 53% were assessed with a DHT. Of 469 patients who received a DHT, 134 (29%) of tests were done on patients who had documentation of at least one characteristic that was inconsistent with a diagnosis of BPPV. Eight patients who received a DHT were ultimately diagnosed with a central cause for their vertigo. CONCLUSIONS: The DHT is both underutilized and frequently applied to patients whose symptoms are not consistent with BPPV. This may result in prolonged patient discomfort and increased resource utilization, as well as increasing the risk of misdiagnosing central vertigo.

RéSUMé: OBJECTIFS: Un simple test de chevet, le test de Dix-Hallpike (DHT), peut diagnostiquer de manière fiable le vertige positionnel paroxystique bénin (VPPB) chez les patients présentant des étourdissements ou des vertiges d'apparition aiguë. Nous avons évalué les modèles d'utilisation de la DHT par les médecins d'urgence chez les patients présentant des étourdissements et des vertiges. Notre objectif était d'évaluer la fréquence et l'utilisation cliniquement appropriée du DHT dans un service d'urgence. MéTHODES: Un examen des dossiers de santé a été réalisé à partir des données de patients qui se sont présentés à un service d'urgence de soins tertiaires entre septembre 2014 et mars 2018 avec une plainte principale de vertige ou d'étourdissements. Les dossiers des patients ont été examinés afin de documenter les symptômes correspondant à l'utilisation du VPPB et de la DHT. RéSULTATS: Au total, 2 309 patients répondaient aux critères d'inclusion. Parmi tous les patients qui avaient des étourdissements et qui avaient une documentation complète des signes et des symptômes compatibles avec le VPPB, 53 % ont été évalués au moyen d'un DHT. Sur 469 patients qui ont reçu une DHT, 134 (29 %) des tests ont été effectués sur des patients qui avaient une documentation d'au moins une caractéristique incompatible avec un diagnostic de VPPB. Huit patients qui ont reçu une DHT ont finalement été diagnostiqués avec une cause centrale pour leur vertige. CONCLUSIONS: La DHT est à la fois sous-utilisée et fréquemment appliquée aux patients dont les symptômes ne correspondent pas au VPPB. Il peut en résulter une gêne prolongée pour le patient et une utilisation accrue des ressources, ainsi qu'un risque accru de diagnostic erroné du vertige central.

Diagnostic Accuracy of the HINTS Exam in an Emergency Department: A Retrospective Chart Review.

INTRODUCTION: The HINTS exam is a series of bedside ocular motor tests designed to distinguish between central and peripheral causes of dizziness in patients with continuous dizziness, nystagmus, and gait unsteadiness. Previous studies, where the HINTS exam was performed by trained specialists, have shown excellent diagnostic accuracy. Our objective was to assess the diagnostic accuracy of the HINTS exam as performed by emergency physicians on patients presenting to the emergency department (ED) with a primary complaint of vertigo or dizziness. METHODS: A retrospective cohort study was performed using data from patients who presented to a tertiary care ED between September 2014 and March 2018 with a primary complaint of vertigo or dizziness. Patient characteristics of those who received the HINTS exam were assessed along with sensitivity and specificity of the test to rule out a central cause of stroke. RESULTS: A total of 2,309 patients met criteria for inclusion in the study. Physician uptake of the HINTS exam was high, with 450 (19.5%) dizzy patients receiving all or part of the HINTS. A large majority of patients (96.9%) did not meet criteria for receiving the test as described in validation studies; most often this was because patients lacked documentation of nystagmus or described their symptoms as intermittent. In addition, many patients received both HINTS and Dix-Hallpike exams, which are intended for use in mutually exclusive patient populations. In no case was dizziness due to a central cause identified using the HINTS exam. CONCLUSIONS: Our results suggest that despite widespread use of the HINTS exam in our ED, its diagnostic value in that setting was limited. The test was frequently used in patients who did not meet criteria to receive the HINTS exam (i.e., continuous vertigo, nystagmus, and unsteady gait). Additional training of emergency physicians may be required to improve test sensitivity and specificity.

Impaired behavioural flexibility related to white matter microgliosis in the TgAPP21 rat model of Alzheimer disease.

Executive dysfunction and white matter inflammation continue to be relatively understudied in rodent models of Alzheimer's disease (AD). Behavioural inflexibility is an important component of executive dysfunction that can be further categorized as perseverative or regressive, which respectively specify whether maladaptive persistence occurs early or late during a behavioural change. Previous studies of the TgAPP21 rat model of AD (expressing pathogenic hAPP) suggested a potentially spontaneous increase of regressive behavioral inflexibility. In this study, 7-8-month-old male TgAPP21 rats were tested for behavioral flexibility, learning, and memory using an operant conditioning chamber and the Morris Water Maze (MWM). TgAPP21 rats demonstrated a regressive behavioral inflexibility during set shifting in an operant conditioning chamber (regressive errors η2 = 0.32 and number of errors after criterion η2 = 0.33). Regressive behavior was also demonstrated in the MWM probe test, wherein TgAPP21 rats significantly increased their swim time in the target quadrant during the last third of the probe test (43% vs 33% in the first 2 thirds of the probe test or the Wt rats' 29%-32%); this behavioral phenotype has not been previously described in the MWM. TgAPP21 demonstrated further impairment of behavioural inflexibility as they committed a greater number of reversal errors in the operant conditioning chamber (η2 = 0.30). Diffuse microglia activation was increased in the white matter tracts of TgAPP21 (corpus callosum, cingulum, and internal capsule; η2 = 0.59-0.62), which was found to correlate with the number of reversal errors in the operant conditioning chamber (R2 = 0.42). As TgAPP21 rats do not spontaneously develop amyloid plaques but have been shown in previous studies to be vulnerable to the development of plaques, these rats demonstrate an important onset of cognitive change and inflammation in the pre-plaque phase of AD. TgAPP21 rats are also an instrumental model for studying the role and mechanism of white matter microglial activation in executive functioning. This is pertinent to clinical research of prodromal AD which has suggested that white matter inflammation may underlie impairment of executive functions such as behavioral flexibility.

Behavioural inflexibility in a comorbid rat model of striatal ischemic injury and mutant hAPP overexpression.

Alzheimer disease (AD) and stroke coexist and interact; yet how they interact is not sufficiently understood. Both AD and basal ganglia stroke can impair behavioural flexibility, which can be reliably modeled in rats using an established operant based set-shifting test. Transgenic Fischer 344-APP21 rats (TgF344) overexpress pathogenic human amyloid precursor protein (hAPP) but do not spontaneously develop overt pathology, hence TgF344 rats can be used to model the effect of vascular injury in the prodromal stages of Alzheimer disease. We demonstrate that the injection of endothelin-1 (ET1) into the dorsal striatum of TgF344 rats (Tg-ET1) produced an exacerbation of behavioural inflexibility with a behavioural phenotype that was distinct from saline-injected wildtype & TgF344 rats as well as ET1-injected wildtype rats (Wt-ET1). In addition to profiling the types of errors made, interpolative modeling using logistic exposure-response regression provided an informative analysis of the timing and efficiency of behavioural flexibility. During set-shifting, Tg-ET1 committed fewer perseverative errors than Wt-ET1. However, Tg-ET1 committed significantly more regressive errors and had a less efficient strategy change than all other groups. Thus, behavioural flexibility was more vulnerable to striatal ischemic injury in TgF344 rats.