In Vivo Ultrasound Shear Wave Elastography Assessment of Acute Compartment Syndrome in a Turkey Model

OBJECTIVE

The aim of the work described here was to evaluate the objectivity and reproducibility of non-invasive intra-compartment pressure (ICP) measurement using ultrasound shear wave elastography (SWE) in a turkey model in vivo and to determine the biological and histologic changes in acute compartment syndrome (ACS).

METHODS

Twenty-four turkeys were randomly divided into four groups based on the duration and fasciotomy of ACS created by infusion of up to 50 mm Hg in the tibialis muscle: group 1, ACS 2 h; group 2, ACS 4 h; group 3, ACS 2 h + fasciotomy 2 h; group 4, ACS 4 h + fasciotomy 2 h. For each turkey, the contralateral limb was considered the control. Time-synchronized measures of SWE and ICP from each leg were collected. Then turkeys were euthanized for histology and quantitative reverse transcription polymerase chain reaction (qRT-PCR) examination.

RESULTS

All models created reproducible increases in ICP and SWE, which had a strong linear relationship (r = 0.802, p < 0.0001) during phase 1. SWE remained stable (50.86 ± 9.64 kPa) when ICP remained at 50.28 ± 2.17 mm Hg in phase 2. After fasciotomy, SWE declined stepwise and then normalized (r = 0.737, p < 0.0001). Histologically, the myofiber diameter of group 2 (82.31 ± 22.92 μm) and group 4 (90.90 ± 20.48 μm) decreased significantly (p < 0.01) compared with that of the control group (103.1 ± 20.39 μm); the interstitial space of all groups increased significantly (p < 0.01). Multifocal muscle damage revealed neutrophilic infiltration, degeneration, hemorrhage and necrosis, especially in group 4. Quantitative RT-PCR verified that interleukin-6 and heparin-binding EGF-like growth factor were significantly increased in group 4.

CONCLUSION

SWE provided sensitive measurements correlating to ICP in a clinically relevant ACS animal model. Once ACS time was exceeded, progression to irreversible necrosis continued spontaneously, even after fasciotomy. SWE may help surgeons in the early detection, monitoring, prognosis and decision making on fasciotomy for ACS.

Does Intrawound Vancomycin Decrease Postoperative Surgical Site Infection in Spine Surgery: A Retrospective Case-control Study

STUDY DESIGN

Retrospective Case-Control series.

OBJECTIVE

The objective of this study is to define the overall postoperative rate of surgical site infection (SSI) in patients undergoing spine surgery and examine the effects of intrawound Vancomycin on postoperative infection rates.

SUMMARY OF BACKGROUND DATA

Surgical site infections (SSI) account for 22% of all health care-associated infections. The use of intrawound Vancomycin in an attempt to reduce the incidence of postoperative SSI has not been sufficiently evaluated in the existing literature.

METHODS

All spine surgeries (n=19,081) from our institution were reviewed from 2003 to 2013. All cases of verified SSI were identified from the database. Cases were then matched to controls in a 1:1 fashion based on age, gender, and date of surgery (+/-30 d). Patient demographics, comorbidities, estimated blood loss, duration of surgery, intrawound administration of Vancomycin, and smoking status were evaluated.

RESULTS

At total of 316 cases of SSI after spine surgery were identified, representing an infection rate of 1.7%. The mean follow-up for cases and controls was 31.5 and 41.6 months, respectively. OR for intrawound Vancomycin was 0.44 (95% CI 0.23-0.88, P=0.019). OR for BMI greater than 30 was 1.63 (95% CI 1.04-2.56, P=0.03).

CONCLUSIONS

In this large cohort of spine surgery patients, administration of intrawound Vancomycin was associated with a significant reduction in postoperative surgical site infections. Further studies are needed to determine appropriate dosing and application as well as long-term safety in spine surgery.

Iatrogenic vertebral artery injury with concomitant contralateral idiopathic vertebral artery dissection managed with intravascular intervention: a case report

Background

Vertebral artery injury (VAI) is a known potential complication of posterior cervical fusion surgery. Pre-operative imaging is used to determine the patency of bilateral vertebral arteries during the planning and execution of surgery. This case illustrates an example of a staged anterior/posterior cervical reconstruction in which an iatrogenic VAI combined with a contralateral idiopathic vertebral artery dissection not identified on pre-operative imaging resulted in absent basilar artery anterograde flow.

Case Description

A 61-year-old female underwent planned staged anterior cervical decompression C4-T1 with posterior cervical fusion C2-T4 for the treatment of degenerative cervical myeloradiculopathy. During the second stage posterior fusion, iatrogenic VAI occurred during drilling for placement of the right C2 pars screw. Upon post-operative angiography, in addition to the known right VAI, there was a new left vertebral artery dissection that occurred during/after the anterior stage. The basilar artery was only filled in retrograde fashion from the right internal carotid artery across the right posterior communicating artery. The left vertebral artery dissection was treated with telescoping flow diverting stents to restore flow to the basilar artery and the right VAI was treated with coiling.

Conclusions

Surgeons should be aware of the possibility, while rare, that an occult injury to the non-injured artery is always a possibility if significant deformity correction or alignment change has occurred during cervical spine surgery. Working closely with neurointerventional colleagues can be invaluable to quickly assess and if necessary, restore blood flow to the brain through these life saving techniques.

Interaction of multidrug-resistant hypervirulent Klebsiella pneumoniae with components of human innate host defense

IMPORTANCE

Klebsiella pneumoniae strains with a combination of multidrug resistance and hypervirulence genotypes (MDR hvKp) have emerged as a cause of human infections. The ability of these microbes to avoid killing by the innate immune system remains to be tested fully. To that end, we compared the ability of a global collection of hvKp and MDR hvKp clinical isolates to survive in human blood and resist phagocytic killing by human neutrophils. The two MDR hvKp clinical isolates tested (ST11 and ST147) were killed in human blood and by human neutrophils in vitro, whereas phagocytic killing of hvKp clinical isolates (ST23 and ST86) required specific antisera. Although the data were varied and often isolate specific, they are an important first step toward gaining an enhanced understanding of host defense against MDR hvKp.

Intraoperative Surgeon Assessment of Bone: Correlation to Bone Mineral Density, CT Hounsfield units and Vertebral Bone Quality

STUDY DESIGN

Retrospective observational study of consecutive patients.

OBJECTIVE

The purpose of the study is to determine if a surgeon's qualitative assessment of bone intraoperatively correlates with radiologic parameters of bone strength.

SUMMARY OF BACKGROUND DATA

Preoperative radiologic assessment of bone can include modalities such as CT Hounsfield Units (HUs), dual-energy x-ray absorptiometry bone mineral density (DXA BMD) with trabecular bone score (TBS) and MRI vertebral bone quality (VBQ). Quantitative analysis of bone with screw insertional torque and pull-out strength measurement has been performed in cadaveric models and has been correlated to these radiologic parameters. However, these quantitative measurements are not routinely available for use in surgery. Surgeons anecdotally judge bone strength, but the fidelity of the intraoperative judgement has not been investigated.

METHODS

All adult patients undergoing instrumented posterior thoracolumbar spine fusion by one of seven surgeons at a single center over a 3-month period were included. Surgeons evaluated the strength of bone based on intraoperative feedback and graded each patient's bone on a 5-point Likert scale. Two independent reviewers measured preoperative CT HUs and MRI VBQ. BMD, lowest T-score and TBS were extracted from DXA within 2 years of surgery.

RESULTS

Eighty-nine patients were enrolled and 16, 28, 31, 13 and 1 patients had Likert grade 1 (strongest bone), 2, 3, 4, and 5 (weakest bone), respectively. The surgeon assessment of bone correlated with VBQ (τ=0.15, P=0.07), CT HU (τ=-0.31, P<0.01), lowest DXA T-score (τ=-0.47, P<0.01), and TBS (τ=-0.23, P=0.06).

CONCLUSION

Spine surgeons' qualitative intraoperative assessment of bone correlates with preoperative radiologic parameters, particularly in posterior thoracolumbar surgeries. This information is valuable to surgeons as this supports the idea that decisions based on feel in surgery have statistical foundation.

Opportunistic CT-Based Hounsfield Units Strongly Correlate with Biomechanical CT Measurements in the Thoracolumbar Spine

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Hounsfield units (HUs) are known to correlate with clinical outcomes, no study has evaluated how they correlate with BCT and DXA measurements.

SUMMARY OF BACKGROUND

Low bone mineral density (BMD) represents a major risk factor for fracture and poor outcomes following spine surgery. Dual-energy x-ray absorptiometry (DXA) can provide regional BMD measurements but has limitations. Opportunistic HUs provide targeted BMD estimates; however, they are not formally accepted for diagnosing osteoporosis in current guidelines. More recently, biomechanical computed tomography (BCT) analysis has emerged as a new modality endorsed by the International Society for Clinical Densitometry (ISCD) for assessing bone strength.

METHODS

Consecutive cases from 2017-2022 at a single institution were reviewed for patients who underwent BCT in the thoracolumbar spine. BCT-measured vertebral strength, trabecular BMD, and the corresponding American College of Radiology (ACR) Classification were recorded. DXA studies within three months of the BCT were reviewed. Pearson Correlation Coefficients were calculated, and receiver-operating characteristic curves were constructed to assess the predictive capacity of HUs. Threshold analysis was performed to identify optimal HU values for identifying osteoporosis and low BMD.

RESULTS

Correlation analysis of 114 cases revealed a strong relationship between HUs and BCT vertebral strength (r=0.69; P<0.0001; R2=0.47) and trabecular BMD (r=0.76; P<0.0001; R2=0.58). However, DXA poorly correlated with opportunistic HUs and BCT measurements. HUs accurately predicted osteoporosis and low BMD (Osteoporosis: C=0.95, 95% CI 0.89-1.00; Low BMD: C=0.87, 95% CI 0.79-0.96). Threshold analysis revealed that 106 and 122 HUs represent optimal thresholds for detecting osteoporosis and low BMD.

CONCLUSION

Opportunistic HUs strongly correlated with BCT-based measures, while neither correlated strongly with DXA-based BMD measures in the thoracolumbar spine. HUs are easy to perform at no additional cost and provide accurate BMD estimates at non-instrumented vertebral levels across all ACR-designated BMD categories.

Subinhibitory Concentrations of Antibiotics Alter the Response of Klebsiella pneumoniae to Components of Innate Host Defense

Carbapenem-resistant Klebsiella pneumoniae isolates classified as multilocus sequence type 258 (ST258) are a problem in health care settings in many countries globally. ST258 isolates are resistant to multiple classes of antibiotics and can cause life-threatening infections, such as pneumonia and sepsis, in susceptible individuals. Treatment strategies for such infections are limited. Understanding the response of K. pneumoniae to host factors in the presence of antibiotics could reveal mechanisms employed by the pathogen to evade killing in the susceptible host, as well as inform treatment of infections. Here, we investigated the ability of antibiotics at subinhibitory concentrations to alter K. pneumoniae capsular polysaccharide (CPS) production and survival in normal human serum (NHS). Unexpectedly, pretreatment with some of the antibiotics tested enhanced ST258 survival in NHS. For example, a subinhibitory concentration of mupirocin increased survival for 7 of 10 clinical isolates evaluated and there was increased cell-associated CPS for 3 of these isolates compared with untreated controls. Additionally, mupirocin pretreatment caused concomitant reduction in the deposition of the serum complement protein C5b-9 on the surface of these three isolates. Transcriptome analyses with a selected ST258 isolate (34446) indicated that genes implicated in the stringent response and/or serum resistance were upregulated following mupirocin treatment and/or culture in NHS. In conclusion, mupirocin and/or human serum causes changes in the K. pneumoniae transcriptome that likely contribute to the observed decrease in serum susceptibility via a multifactorial process. Whether these responses can be extended more broadly and thus impact clinical outcome in the human host merits further investigation. IMPORTANCE The extent to which commensal bacteria are altered by exposure to subinhibitory concentrations of antibiotics (outside resistance) remains incompletely determined. To gain a better understanding of this phenomenon, we tested the ability of selected antibiotics (at subinhibitory concentrations) to alter survival of ST258 clinical isolates in normal human serum. We found that exposure of ST258 to antibiotics at low concentrations differentially altered gene expression, capsule production, serum complement deposition, and bacterial survival. The findings were isolate and antibiotic dependent but provide insight into a potential confounding issue associated with ST258 infections.

In a large dataset of primary care patients, use of CHA2DS2-VA score leads to almost universal recommendation for anticoagulation in those aged 65 years and over with atrial fibrillation

Background

Treatment with oral anticoagulants (OAC) for high-risk atrial fibrillation (AF) patients can reduce stroke risk by two-thirds. From 2012–14, the OAC treatment recommendation threshold in international guidelines moved from CHADS2 ≥2 to CHA2DS2-VASc ≥2 (men) or ≥3 (women), equivalent to a “sexless” CHA2DS2-VA≥2. This move aimed to identify truly low risk patients who did not need OAC treatment. General practitioners (GPs) report barriers about assessing patient suitability for OAC.

Objectives

To compare the proportion of AF patients for whom OAC treatment is recommended under CHADS2 ≥2 and CHA2DS2-VA ≥2, and to look at the drivers of any differences, using an existing dataset.

Methods

Analyses were conducted on a large Australian general practice dataset collated during previous studies (2011–2019), with deidentified data extracted from the clinical records system at a single timepoint for regularly-attending adult patients from 164 practices. CHADS2 and CHA2DS2-VA scores were calculated for AF patients with sufficient data available and the proportion with CHADS2 and CHA2DS2-VA ≥2 was compared using chi-square tests.

Results

There were records for 340,463 patients, of which 285,635 (8,294 with AF) had sufficient data to calculate CHADS2 and CHA2DS2-VA scores. Among AF patients of all ages, the CHA2DS2-VA ≥2 threshold captured a significantly higher proportion than CHADS2≥2 (85% vs 68%, p&lt;0.0001). In AF patients aged ≥65 years, the CHA2DS2-VA ≥2 threshold also captured a significantly higher proportion than CHADS2 ≥2 (96% vs 76%, p&lt;0.0001). Almost all older patients (≥65 years) who were captured by CHA2DS2-VA ≥2 but not CHADS2 ≥2 (n=1395) qualified on the basis of age, with only 1.4% eligible because of age 65–74 years and vascular disease history.

Conclusions

The change from CHAD2 to CHA2DS2-VA has resulted in a significantly higher proportion of patients with AF being recommended OAC treatment under the guidelines, driven almost entirely by the revised scoring for age. Among AF patients aged ≥65 years, almost all (96%) were recommended OAC treatment under CHA2DS2-VA, demonstrating that AF is strongly associated with other vascular pathology. These findings support the Canadian guidelines, which recommend OAC treatment for all AF cases aged ≥65 years. The findings also reinforce the argument that AF screening in those aged ≥65 years is justified, as almost all patients with prevalent AF in that age group are eligible for OAC treatment.

These results suggest could be an argument for simplifying the treatment message for GPs, which may reduce barriers and further improve treatment rates. High rates of associated vascular pathology in AF patients suggest that additional management strategies are also justified, including promotion of exercise, smoking cessation, and treatment of associated conditions such as hypertension and diabetes.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): RACGP Foundation / HCF Research Foundation GrantUniversity of Notre Dame Australia Research Grant

Association between lower Hounsfield units and proximal junctional kyphosis and failure at the upper thoracic spine

OBJECTIVE

The aim of this study was to analyze risk factors and avoidance techniques for proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) in the upper thoracic spine with an emphasis on bone mineral density (BMD) as estimated by Hounsfield units (HU).

METHODS

A retrospective chart review identified patients at least 50 years of age who underwent instrumented fusion extending from the pelvis to an upper instrumented vertebra (UIV) between T1 and T6 and had a preoperative CT, pre- and postoperative radiographs, and a minimum follow-up of 12 months. HU were measured in the UIV, the vertebral body cephalad to the UIV (UIV+1), and the L3 and L4 vertebral bodies. Numerous perioperative variables were collected, including basic demographics, smoking and steroid use, preoperative osteoporosis treatment, multiple frailty indices, use of a proximal junctional tether, UIV soft landing, preoperative dual-energy x-ray absorptiometry, spinopelvic parameters, UIV screw tip distance to the superior endplate, UIV pedicle screw/pedicle diameter ratio, lumbar lordosis distribution, and postoperative spinopelvic parameters compared with age-adjusted normal values.

RESULTS

Eighty-one patients were included in the study (21 men and 60 women) with a mean (SD) age of 66 years (6.9 years), BMI of 29 (5.5), and follow-up of 38 months (25 months). Spinal fusion constructs at the time of surgery extended from the pelvis to a UIV of T1 (5%), T2 (15%), T3 (25%), T4 (33%), T5 (21%), and T6 (1%). Twenty-seven patients (33%) developed PJK and/or PJF; 21 (26%) had PJK and 15 (19%) had PJF. Variables associated with PJK/PJF with p < 0.05 were included in the multivariable analysis, including HU at the UIV/UIV+1, HU at L3/L4, DXA femoral neck T-score, UIV screw tip distance to the superior endplate, UIV pedicle screw/pedicle diameter ratio, and postoperative lumbar lordosis distribution. Multivariable analysis (area under the curve = 0.77) demonstrated HU at the UIV/UIV+1 to be the only independent predictor of PJK and PJF with an OR of 0.96 (p = 0.005). Patients with < 147 HU (n = 27), 147-195 HU (n = 27), and > 195 HU (n = 27) at the UIV/UIV+1 had PJK/PJF rates of 59%, 33%, and 7%, respectively.

CONCLUSIONS

In patients with upper thoracic-to-pelvis spinal reconstruction, lower HU at the UIV and UIV+1 were independently associated with PJK and PJF, with an optimal cutoff of 159 HU that maximizes sensitivity and specificity.

Independent predictors of vertebral compression fracture following radiation for metastatic spine disease

OBJECTIVE

The goal of this study was to determine independent risk factors for vertebral compression fracture (VCF) following radiation for metastatic spine disease, including low bone mineral density as estimated by Hounsfield units (HU).

METHODS

A retrospective chart review identified patients with a single vertebral column metastasis treated with radiation therapy, a pretreatment CT scan, and a follow-up CT scan at least 6 weeks after treatment. Patients with primary spine tumors, preradiation vertebroplasty, preradiation spine surgery, prior radiation to the treatment field, and proton beam treatment modality were excluded. The HU were measured in the vertebral bodies at the level superior to the metastasis, within the tumor and medullary bone of the metastatic level, and at the level inferior to the metastasis. Variables collected included basic demographics, Spine Instability Neoplastic Score (SINS), presenting symptoms, bone density treatment, primary tumor pathology, Weinstein-Boriani-Biagini (WBB) classification, Enneking stage, radiation treatment details, chemotherapy regimen, and prophylactic vertebroplasty.

RESULTS

One hundred patients with an average age of 63 years and average follow-up of 18 months with radiation treatment dates ranging from 2017 to 2020 were included. Fifty-nine patients were treated with external-beam radiation therapy, with a median total dose of 20 Gy (range 8-40 Gy). Forty-one patients were treated with stereotactic body radiation therapy, with a median total dose of 24 Gy (range 18-39 Gy). The most common primary pathologies included lung (n = 22), prostate (n = 21), and breast (n = 14). Multivariable logistic regression analysis (area under the curve 0.89) demonstrated pretreatment HU (p < 0.01), SINS (p = 0.02), involvement of ≥ 3 WBB sectors (p < 0.01), primary pathology other than prostate (p = 0.04), and ongoing chemotherapy treatment (p = 0.04) to be independent predictors of postradiation VCF. Patients with pretreatment HU < 145 (n = 32), 145-220 (n = 31), and > 220 (n = 37) had a fracture rate of 59%, 39%, and 11%, respectively. An HU cutoff of 157 was found to maximize sensitivity (71%) and specificity (75%) in predicting postradiation VCF.

CONCLUSIONS

Low preradiation HU, higher SINS, involvement of ≥ 3 WBB sectors, ongoing chemotherapy, and nonprostate primary pathology were independent predictors of postradiation VCF in patients with metastatic spine disease. Low bone mineral density, as estimated by HU, is a novel and potentially modifiable risk factor for VCF.

Is there consensus on the perioperative management of Xa inhibitors in patients undergoing elective spine surgery?-A survey of current spine surgeon practices

BACKGROUND

Factor Xa inhibitors (Xai) are an increasingly common consideration in perioperative anticoagulation management. However, there no existing guidelines established for use in Spine Surgery. This survey study aims to capture current practice trends regarding the perioperative management of Xai among spine surgeons.

METHODS

An 11-question survey was sent to all surgeon members of 3 spinal surgery societies. Responses were remitted anonymously. Questions characterized the background and experience of the respondent and inquired into their current perioperative Xai and other anticoagulant management. Questions were all single-best option, multiple-choice.

RESULTS

A total of 116 surveys were received. Twenty-six (22.4%) were from neurosurgeons and 90 (77.6%) were from orthopedic surgeons. Practiced preoperative Xai hold length tended to be longer than recommended by the respondent's medical colleagues. Only 65.2% (P≤0.0001) of respondents practiced in agreement with the recommendations of their medical colleagues. Postoperative Xai holds trended toward longer holds than that of other anticoagulants with 37.9% (P=0.0125) of respondents showed differences within their own practice between length of Xai hold and length of other anticoagulant holds. One out of four respondents reported noticing a change in the rate of perioperative bleeding complications among Xai patients. Despite reported increased bleeding issues, only 39% of those who noted this increase in bleeding complications reported they would hold a Xai longer than other anticoagulants.

CONCLUSIONS

There exists a wide range of recommended and practiced chronic anticoagulant hold lengths. This inconsistency likely highlights conflicting risk aversion among surgeons, between complications which are viewed as medical (i.e., thromboembolism and stroke) vs. surgical (i.e., compressive hematoma). Yet, survey responses suggest the length of Xai hold times did not necessarily reflect the surgeon's experience with postoperative bleeding complications in Xai patients. These inconsistent practices highlight the need for further research that can establish guidelines for perioperative management of Xai patients undergoing spine surgery.

KEYWORDS

Anticoagulants; factor Xa inhibitors (factor Xai); spine; orthopedic surgery; neurosurgery.

Atrial fibrillation self-screening, management and guideline recommended therapy (AF SELF SMART): improving AF screening in general practice by utilising self-screening stations in GP waiting rooms

Background

Opportunistic screening for silent atrial fibrillation (AF) is recommended to reduce stroke, but screening rates are sub-optimal in Australian general practice (&lt;15%), with practitioners reporting time constraints being the main barrier. Previous AF screening interventions in general practice have not been able to exceed screening rates of ∼34% eligible patients which is sub-optimal for stroke prevention.

Purpose

To increase the proportion of patients screened for AF in general practice by implementing AF self-screening stations in waiting rooms.

Methods

We developed and tested an AF self-screening station using a single-lead ECG and app with automated ECG analysis. We also developed customised software which fully integrates the self-screening station with GP medical software and the practice workflow (Figure 1). The system: 1) automatically identifies eligible patients (aged ≥65 years, no AF diagnosis) from the practice appointment diary, and sends an SMS regarding self-screening prior to their appointment; 2) automatically creates individualised patient QR codes, which provided to the patient by the receptionist; 3) the patient then scans QR code and self-screens at station in waiting room; 4) the ECG and result are automatically imported into patient record before the GP consultation.

Results

Three general practices in New South Wales, Australia, were recruited. Each practice participated for approximately 3-months (between August 2020 and March 2021). During this period 825 patients completed AF self-screening, mean age 74.2 years and 45% male. When expressed as a proportion of the actual eligible patients attending the practice during the study period, the mean proportion screened in practices was 52% (range 38–65%). The device algorithm indicated “Possible AF” in 37/825 patients (4.5%); mean age 77.2 years 43% male.

Conclusion

An AF self-screening station placed in GP waiting rooms that is integrated with the practice software and workflow may achieve higher screening rates for AF in general practice than standard practice, and therefore contribute to greater reductions in stroke.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Investigator-lead grant from Bristol Myers Squibb and Pfizer

Patient self-screening stations for atrial fibrillation in general practice waiting rooms: process evaluation

Background

Our previous work has identified factors relevant to general practitioner (GP)-led screening for atrial fibrillation (AF) in Australian general practices, with GPs indicating significant time constraints. AF SELF SMART (Atrial fibrillation self-screening, management and guideline recommended therapy) allows for opportunistic patient self-screening using purpose-built screening stations located in GP waiting rooms (figure 1). It utilises a single-lead ECG, with results automatically imported into the patient medical record for review during the GP consultation. AF SELF SMART may increase screening rates, but acceptability by practice staff is unknown.

Purpose

Determine staff perspectives on opportunistic self-screening in practice waiting rooms, utilising AF SELF SMART.

Method

14 semi-structured interviews have been conducted with practice staff (GPs, receptionists and practice managers) across 3 practices participating in the AF SELF SMART pilot, with thematic analysis of results.

Results

Several themes were identified.

All staff acknowledged the importance of increasing screening for AF in the practice. GPs in particular placed a high value on AF screening for stroke prevention. GPs valued the increased information and accuracy provided by AF SELF SMART, as previously they checked patients for AF using manual methods, either routinely or as clinically indicated. There were differential impacts on workflow. GPs reported some small increase in workload but these were seen as being acceptable given the benefits of the program. Receptionists and Practice Managers reported significant interruptions to normal workflow associated with assisting patients. Receptionists routinely offered patients help with screening instead of patients screening independently. Staff perceived that patients were either unable to negotiate the self-screening process by themselves, or did not want to try. Given the increase in workload associated with assisting patients, and as screening was not receptionists' main priority, not all patients were offered self-screening during busy periods. Patient refusal was also identified as a factor limiting uptake.

Conclusion

While AF self-screening may increase screening rates, further process improvements are required to reduce impact on reception staff, and enhance the usability of the self-screening station for patients. Such improvements may increase acceptability and ongoing sustainability at a practice level.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Investigator initiated research grant from Bristol-Myers Squibb/Pfizer Alliance Figure 1. Self-screening station

Atrial fibrillation screening: feasible approaches and implementation challenges across Europe

Background

Atrial fibrillation (AF) screening has the potential to increase early detection and possibly reduce complications of AF. Guidelines recommend screening, but the most appropriate approaches are unknown.

Purpose

We aimed to explore the views of stakeholders across Europe about the opportunities and challenges of implementing four different AF screening scenarios.

Method

This qualitative study included 21 semi-structured interviews with healthcare professionals and regulators potentially involved in AF screening implementation in nine European countries. Data were analysed using thematic analysis.

Results

Three themes evolved. 1) Current approaches to screening: there are no national AF screening programmes, with most AF detected in symptomatic patients. Patient-led screening exists via personal devices, creating screening inequity by the reach of screening programmes being limited to those who access healthcare services. 2) Feasibility of screening approaches: single time point opportunistic screening in primary care using single lead ECG devices was considered the most feasible approach and AF screening may be possible in previously unexplored settings such as dentists and podiatrists. Software algorithms may aid identification of patients suitable for screening and telehealth services have the potential to support diagnosis. However, there is a need for advocacy to encourage the use of telehealth to aid AF diagnosis, and training for screening familiarisation and troubleshooting.

3) Implementation requirements: sufficient evidence of benefit is required. National rather than pan-European screening processes must be developed due to different payment mechanisms and health service regulations.

There is concern that the rapid spread of wearable devices for heart rate monitoring may increase workload due to false positives in low risk populations for AF. Data security and inclusivity for those without access to primary care or personal devices must be addressed.

Conclusions

There is an overall awareness of AF screening. Opportunistic screening appears to be most feasible across Europe. Challenges that need to be addressed concern health inequalities, identification of best target groups for screening, streamlined processes, the need for evidence of benefit, and a tailored approach adapted to national realities.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): H2020 Screening ScenariosGraphical abstract

One size does not fit all – a realist review of screening for asymptomatic atrial fibrillation in Indigenous communities in Australia, Canada, New Zealand and United States

Background/Introduction

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and it is increasing in prevalence and incidence globally. True prevalence is underestimated because silent/asymptomatic AF is frequent and under-detected, but can cause stroke. Guidelines recommend opportunistic screening for AF in patients aged ≥65 years old. A growing body of evidence from hospital and community-based studies in Australia, New Zealand, Canada and United States indicates this age limit is lower for Indigenous people. Screening for AF meets the World Health Organisation (WHO) criteria for successful routine screening, yet little is known about successful implementation of AF screening in Indigenous communities in developed countries.

Purpose

The aim of this study is to use a realist approach to identify what works, how, for whom and under what circumstances for AF screening of Indigenous communities in Australia, Canada, New Zealand and United States.

Methods

In the realist review, eight databases were searched for studies targeted at AF screening in Indigenous communities. Realist analysis was used to identify context-mechanism-outcome configurations across 11 included records (reporting on 5 studies). Snowball referencing and grey literature were used to iteratively incorporate evidence to enhance the refined programme theory that was the product of the realist analysis.

Results

The realist review included studies using multiple screening strategies such as using tools to increase screening, using different screening environments and training screeners to provide culturally centred care. The realist analysis identified a number of mechanisms that can improve AF screening in Indigenous communities. The contextual factors enabling AF screening programs in Indigenous communities include wider community engagement, opportunistic non-clinical settings, using portable and easy to use devices, increasing knowledge, motivation and confidence in screening amongst Indigenous healthcare workers as well as improving follow-up protocols for abnormal results tailored to screen setting. Barriers to effective AF screening include time-poor working environments, conflicting cultural issues, navigating communication of abnormal results and logistical issues with device use (Figure 1).

Conclusion(s)

Since the life-course risk for AF in Indigenous population is different, a modified screening strategy needs to be put in place. This realist review provides lessons learned for successful implementation of AF screening programs for Indigenous communities. In order to tackle the gap in cardiovascular burden in Indigenous people, this study calls for action to develop AF screening guidelines for Indigenous populations and provides a guide for policy makers about timely and effective AF screening programs for Indigenous communities.

Funding Acknowledgement

Type of funding sources: None.

A Multicenter Evaluation of the Feasibility, Patient/Provider Satisfaction, and Value of Virtual Spine Consultation During the COVID-19 Pandemic

Objective

To assess the feasibility, patient/provider satisfaction, and perceived value of telehealth spine consultation after rapid conversion from traditional in-office visits during the COVID-19 pandemic.

Methods

Data were obtained for patients undergoing telehealth visits with spine surgeons in the first 3 weeks after government restriction of elective surgical care at 4 sites (March 23, 2020, to April 17, 2020). Demographic factors, technique-specific elements of the telehealth experience, provider confidence in diagnostic and therapeutic assessment, patient/surgeon satisfaction, and perceived value were collected.

Results

A total of 128 unique visits were analyzed. New (74 [58%]), preoperative (26 [20%]), and postoperative (28 [22%]) patients were assessed. A total of 116 (91%) visits had successful connection on the first attempt. Surgeons felt very confident 101 times (79%) when assessing diagnosis and 107 times (84%) when assessing treatment plan. The mean and median patient satisfaction was 89% and 94%, respectively. Patient satisfaction was significantly higher for video over audio-only visits (P < 0.05). Patient satisfaction was not significantly different with patient age, location of chief complaint (cervical or thoracolumbar), or visit type (new, preoperative, or postoperative). Providers reported that 76% of the time they would choose to perform the visit again in telehealth format. Sixty percent of patients valued the visit cost as the same or slightly less than an in-office consultation.

Conclusions

This is the first study to demonstrate the feasibility and high patient/provider satisfaction of virtual spine surgical consultation, and appropriate reimbursement and balanced regulation for spine telehealth care is essential to continue this existing work.

Teriparatide Treatment Increases Hounsfield Units in the Thoracic Spine, Lumbar Spine, Sacrum, and Ilium Out of Proportion to the Cervical Spine

STUDY DESIGN

This was a retrospective chart review.

OBJECTIVE

The objective of this study was to compare the effect of teriparatide on Hounsfield Units (HU) in the cervical spine, thoracic spine, lumbar spine, sacrum, and pelvis. Second, to correlate HU changes at each spinal level with bone mineral density (BMD) on dual-energy x-ray absorptiometry (DXA).

SUMMARY OF BACKGROUND DATA

HU represent a method to estimate BMD and can be used either separately or in conjunction with BMD from DXA.

MATERIALS AND METHODS

A retrospective chart review included patients who had been treated with at least 6 months of teriparatide. HU were measured in the vertebral bodies of the cervical, thoracic, and lumbosacral spine and iliac crests. Lumbar and femoral neck BMD as measured on DXA was collected when available.

RESULTS

One hundred twenty-five patients were identified for analysis with an average age of 67 years who underwent a mean (±SD) of 22±8 months of teriparatide therapy. HU improvement in the cervical spine was 11% (P=0.19), 25% in the thoracic spine (P=0.002), 23% in the lumbar spine (P=0.027), 17% in the sacrum (P=0.11), and 29% in the iliac crests (P=0.09). Lumbar HU correlated better than cervical HU with BMD as measured on DXA.

CONCLUSIONS

Teriparatide increased average HU in the thoracolumbar spine to a proportionally greater extent than the cervical spine. The cervical spine had a higher baseline starting HU than the thoracolumbar spine. Lumbar HU correlated better than cervical and thoracic HU with BMD as measured on DXA.

Lower Hounsfield Units at the Upper Instrumented Vertebrae are Significantly Associated With Proximal Junctional Kyphosis and Failure Near the Thoracolumbar Junction

BACKGROUND

Low bone mineral density (BMD) on dual energy x-ray absorptiometry (DXA) is likely a risk factor for proximal junctional kyphosis (PJK) and proximal junctional failure (PJF). However, prior instrumentation and degenerative changes can preclude a lumbar BMD measurement. Hounsfield units (HU) represent an alternative method to estimate BMD via targeted measurements at the intended operative levels.

OBJECTIVE

To determine if patients with lower HU at the upper instrumented vertebrae (UIV) and vertebral body superior to the UIV (UIV + 1) are at greater risk for PJK and PJF.

METHODS

A retrospective chart review identified patients at least 50 yr of age who underwent instrumented lumbar fusion with pelvic fixation, a UIV from T10 to L2, and a preoperative computed tomography (CT) encompassing the UIV. HU were measured at the UIV, UIV + 1, and the L3-L4 vertebral bodies.

RESULTS

A total of 150 patients (80 women and 70 men) were included with an average age of 66 yr and average follow-up of 32 mo. Multivariable logistic regression analysis with an area under the curve (AUC) of 0.89 demonstrated HU at the UIV/UIV + 1 as the only independent predictor of PJK/PJF with an odds ratio of 0.94 (P-value = .031) for a change in a single HU. Patients with HU at UIV/UIV + 1 of <110 (n = 35), 110 to 160 (n = 73), and >160 (n = 42) had a rate of PJK/PJF of 63%, 27%, and 12%, respectively (P-value < .001).

CONCLUSION

Patients with lower HU at the UIV and UIV + 1 were significantly associated with PJK and PJF, with an optimal cutoff of 122 HU that maximizes sensitivity and specificity.

Performance of automated single-lead ECG atrial fibrillation screening is associated with patient characteristics

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): The investigators received and unrestricted research grant by Pfizer/BMS. Pfizer/BMS was not involved in the planning, conduction, analysis, or interpretation of the data.

Introduction

Screening for atrial fibrillation (AF) with a single-lead electrocardiogram device is on the rise. However, little is known about influence of automated AF screening performance related to patient characteristics.

Aim

We tested the accuracy of automated AF detection of a single-lead ECG device and identified factors associated with diagnostic performance.

Methods

In 6482 subjects of community-pharmacies a single-time point AF screening was performed. All ECGs were analyzed by blinded human overread and compared to the automated results in context of patient characteristics.

Results

Automated screening showed good prediction of AF with an area under the receiver operating curve of 0.89; sensitivity 80%; specificity 98%; positive predictive value 71%; negative predictive value 99%. Good ECG signal quality was highly associated with correct measurement, while low signal quality leads to incorrect measurements. In a multivariate model we determined factors associated with excellent signal quality and as counterexample incorrect automatic AF identification. The Odds’ ratio (OR) for excellent signal quality was strongly associated with female sex, lower age, lower height, and higher body weight index (table).

Conclusion

The performance of automated AF screening is influenced by sex, age, height and body mass index. Potential target population groups, with high AF prevalence, have a higher chance of incorrect automatic measurement. We recommend an expert over-read, at least for all AF positive ECG recordings. Table 1 Excellent signal quality Incorrect measurement Univariate analysis Multivariate analysis Univariate analysis Multivariate analysis Parameter OR 95% CI P OR 95% CI P OR 95% CI P OR 95% CI P Sex [Female] 2.33 1.97-2.75 &lt;0.001 1.92 1.53-2.41 &lt;0.001 0.64 0.49-0.84 0.001 0.57 0.43-0.76 &lt;0.001 Age [years] 0.97 0.96-0.98 &lt;0.001 0.97 0.96-0.98 &lt;0.001 1.07 1.04-1.09 &lt;0.001 1.06 1.04-1.09 &lt;0.001 Height [cm] 0.96 0.95-0.97 &lt;0.001 0.98 0.97-0.99 0.003 1.01 0.99-1.03 0.068 Weight [kg] 0.99 0.99-1.00 0.418 0.99 0.98-0.99 0.003 BMI [kg/cm2] 1.04 1.03-1.06 &lt;0.001 1.04 1.03-1.06 &lt;0.001 0.91 0.88-0.95 &lt;0.001 0.91 0.87-0.94 &lt;0.001 CHADSVASC 1 0.95-1.06 0.912 1.06 0.97-1.17 0.205 Heart failure 0.62 0.41-0.93 0.022 1.86 1.13-3.05 0.015 Hypertension 0.96 0.83-1.11 0.58 1.06 0.80-1.39 0.689 Diabetes mellitus 0.85 0.68-1.07 0.159 0.82 0.54-1.25 0.359 Stroke / TIA 0.82 0.66-1.01 0.066 1.19 0.83-1.69 0.341 Vascular disease 0.89 0.75-1.07 0.213 1.31 0.98-1.77 0.70 OR – odd’s ratio, CI – confidence interval

Revision Anterior Cervical Discectomy and Fusion and Revision Cervical Arthroplasty Are Associated with Similar Outcomes: Real-World Analysis from a National Quality Registry

AIM

Anterior cervical discectomy and fusion (ACDF) and cervical disc arthroplasty (CDA) are commonly employed cervical spine procedures for degenerative cervical spine pathology. However, patients may require a revision procedure, most commonly due to recurrence of same-level pathology, adjacent segment disease or hardware related complications. In the current study, we sought to utilize a national surgical quality registry to compare 30-day quality outcomes between repeat ACDF and CDA Material and Methods: The National Surgical Quality Improvement Project (NSQIP) Participant User Files (PUF) for the years 2005- 2018 was queried for patients undergoing repeat ACDF and CDA using current procedural terminology (CPT) and international classification of disease (ICD)-9th version codes. We compared demographic and baseline clinical characteristics, operative characteristics and 30-day readmissions, reoperations, and complications between the two groups. We also performed multivariable analyses to assess the impact of repeat procedure type on outcomes of interest.

RESULTS

A total of 3,957 patients were identified, of which 182 patients underwent a revision/removal of arthroplasty while 3,775 patients underwent revision or removal of fusion. Up to 4.6% patients (n=179) in the repeat ACDF group had a complication, compared to 0.5% (n=1) in the CDA group. The 30-day readmission rate was found to be similar between the two groups (repeat-ACDF: 3.8% (n=145), vs repeat-CDA: 2.2% (n=4); p=0.23). Similarly, the 30-day reoperation rate was also not found to be different between the two groups (repeat-ACDF: 3.9% (n=149) vs repeat-CDA: 2.7% (n=5);p=0.39). On multivariable analysis, removal or revision ACDF was only found to be significantly associated with an increased risk of 30-day complications (OR: 8.00, 95% CI: 1.07-59.79, p=0.04).

CONCLUSION

Repeat ACDF or repeat CDA can be performed safely and are associated with optimal 30-day outcomes, comparable to those for index procedures. However, patients undergoing revision ACDF, compared to those undergoing revision CDA may be slightly more likely to have a complication.

Change in pelvic incidence between the supine and standing positions in patients with bilateral sacroiliac joint vacuum signs

OBJECTIVE

Pelvic incidence (PI) is a commonly utilized spinopelvic parameter in the evaluation and treatment of patients with spinal deformity and is believed to be a fixed parameter. However, a fixed PI assumes that there is no motion across the sacroiliac (SI) joint, which has been disputed in recent literature. The objective of this study was to determine if patients with SI joint vacuum sign have a change in PI between the supine and standing positions.

METHODS

A retrospective chart review identified patients with a standing radiograph, supine radiograph, and CT scan encompassing the SI joints within a 6-month period. Patients were grouped according to their SI joints having either no vacuum sign, unilateral vacuum sign, or bilateral vacuum sign. PI was measured by two independent reviewers.

RESULTS

Seventy-three patients were identified with an average age of 66 years and a BMI of 30 kg/m2. Patients with bilateral SI joint vacuum sign (n = 27) had an average absolute change in PI of 7.2° (p < 0.0001) between the standing and supine positions compared to patients with unilateral SI joint vacuum sign (n = 20) who had a change of 5.2° (p = 0.0008), and patients without an SI joint vacuum sign (n = 26) who experienced a change of 4.1° (p = 0.74). ANOVA with post hoc Tukey test showed a statistically significant difference in the change in PI between patients with the bilateral SI joint vacuum sign and those without an SI joint vacuum sign (p = 0.023). The intraclass correlation coefficient between the two reviewers was 0.97 for standing PI and 0.96 for supine PI (p < 0.0001).

CONCLUSIONS

Patients with bilateral SI joint vacuum signs had a change in PI between the standing and supine positions, suggesting there may be increasing motion across the SI joint with significant joint degeneration.

Comparable risk of ischemic stroke in patients with screen-detected atrial fibrillation on single timepoint handheld ECG screening to patients with known AF

Aims

To determine risk of ischemic stroke in patients with single timepoint screen-detected atrial fibrillation (AF).

Methods

Cohort of 11,972 consecutive patients aged ≥65 years attending medical outpatient clinics in Hong Kong underwent AF screening using a handheld single-lead ECG (AliveCor) from Dec 2014 to Dec 2017 (NCT02409654). Repeated screening was performed in patients who had &gt;1 clinic visit during the study period. Cohort was divided into 4 exposure groups: (i) new AF detected by initial screening (S1-AF); (ii) new AF detected by subsequent screening or clinically diagnosed during follow up (FU-AF); (iii) known AF and (iv) no initial or subsequent FU-AF (no AF). Exposure in the FU-AF group was handled as a time-dependent variable. All AF exposure groups were further stratified by oral anticoagulant (OAC) use at the end of FU. Cumulative incidence of ischemic stroke was compared between groups during a median FU period of 2.3 (IQR=1.7–3.3) years, using Fine and Gray regression accounting for death as competing risk and using no AF as reference.

Results

Of 11,972 subjects enrolled, 2,236 (18.7%) had known AF and 9,736 (81.3%) underwent 13,571 screening events during the study period. The yield of newly diagnosed AF on initial screening was 2.3% (n=223/9,736), with 71 new AF detected by subsequent screening. During FU, 2.3% (221/9,442) screen-negative patients were diagnosed with AF clinically. Compared to no AF, S1-AF without OAC had the highest ischemic stroke risk (subdistribution hazard ratio (SHR)=2.79; 1.47–5.27), then FU-AF without OAC (SHR=2.66; 1.21–5.82) and known AF without OAC (SHR=1.97; 1.50–2.57). All AF groups taking OAC had similar risk of ischemic stroke as no AF.

Conclusion

This is the first study to report the prognosis of AF detected by single timepoint screening. The prognosis is not benign. Both risks of stroke and benefits from anticoagulation therapy were similar between screen-detected and known AF.

Funding Acknowledgement

Type of funding source: None

223Atrial fibrillation screen, management and guideline recommended therapy (AF SMART II) in the rural primary care setting: eHealth tools to support all stages of screening

Funding Acknowledgements

National Heart Foundation of Australia: CVRN Grant and Vanguard Grant; investigator-initiated grant from Pfizer-BMS; AliveCor provided free devices

BACKGROUND

Internationally, most atrial fibrillation (AF) management guidelines recommend screening for AF in people aged ≥65 years, as well as treatment with oral anticoagulants (OAC) for those at high stroke risk ( CHA2DS2-VA ≥2). However, in practice, gaps remain in both screening and treatment. In Australian general practice in 2017, the estimated rate of AF screening was 11%, and only about 60% of diagnosed AF patients received guideline-based OAC. Our 2018 screening study using eHealth tools in metropolitan general practices increased screening to 16% of eligible patients, leading to further refinement of the eHealth tools.

PURPOSE

To investigate the impact of an AF screening program in rural general practices, using a suite of custom-designed eHealth tools designed to increase the proportion screened and treated for AF in accordance with guidelines.

METHODS

General practices (n = 8) in rural New South Wales, Australia participated in the study between September 2018 – June 2019. General practitioners (GPs) and practice nurses conducted opportunistic screening of eligible patients (i.e. aged ≥65 years without existing AF diagnosis) using a smartphone electrocardiogram during practice visits. Practices were also provided with 1) an electronic screening prompt (which appeared when an eligible patient’s file was opened); 2) electronic decision support based on ESC/Australian treatment guidelines; and 3) regular customised data reports aimed at quality improvement (Figure 1). A clinical audit tool was used to extract deidentified data from practices.

RESULTS

A total of 3,103 eligible patients (mean age 75.1 ± 6.8 years, 47% male) who attended the 8 practices during the study period were screened (median screening period 4.6 months). Practices screened a median of 35% of eligible patients (range 9-51% per practice), with 4/8 practices screening &gt;40% of eligible patients. 36 (1.2%) new cases of AF were confirmed (mean age 77.0 years, 64% male, mean CHA2DS2-VA = 2.9). GPs (n = 22) screened 30% (range 1-182 per GP) of patients and nurses (n = 40) screened 70% (range 1-192 per nurse). OAC treatment rates of patients with AF with CHA2DS2-VA≥2 were 82% (screen-detected), 78% (clinically-detected during study period) and 75% (pre-existing AF), with no significant differences between groups.

CONCLUSIONS

In the rural general practice setting, an AF screening program supported by eHealth tools resulted in 35% of eligible people screened, which is substantially higher than the 16% achieved in our previous study. Half the practices screened 40-50% of eligible patients, suggesting this may represent a ‘ceiling’ of patients captured by opportunistic AF screening programs. OAC treatment rates were higher than previous studies at baseline and were trending upwards during the study. eHealth tools, particularly including customised data reports as part of an audit and feedback system, may be a valuable addition to future screening programs.

Abstract Figure 1 - screening process

An Objective and Reliable Method for Identifying Sarcopenia in Lumbar Spine Surgery Patients: Using Morphometric Measurements on Computed Tomography Imaging

Study Design

A retrospective observational study.

Purpose

Establish a quantifiable and reproducible measure of sarcopenia in patients undergoing lumbar spine surgery based on morphometric measurements from readily available preoperative computed tomography (CT) imaging.

Overview of Literature

Sarcopenia—the loss of skeletal muscle mass—has been linked with poor outcomes in several surgical disciplines; however, a reliable and quantifiable measure of sarcopenia for future assessment of outcomes in spinal surgery patients has not been established.

Methods

A cohort of 90 lumbar spine fusion patients were compared with 295 young, healthy patients obtained from a trauma da¬tabase. Cross-sectional vertebral body (VB) area, as well as the areas of the psoas and paravertebral muscles at mid-point of pedicles at L3 and L4 for both cohorts, was measured using axial CT imaging. Total muscle area-to-VB area ratio was calculated along with intraclass correlation coefficients for interobserver and intraobserver reliability. Finally, T-scores were calculated to help identify those patients with considerably diminished muscle-to-VB area ratios.

Results

Both muscle mass and VB areas were considerably larger in males compared with those in females, and the ratio of these two measures was not enough to account for large differences. Thus, a gender-based comparison was made between spine patients and healthy control patients to establish T-scores that would help identify those patients with sarcopenia. The ratio for paravertebral muscle area-to-VB area at the L4 level was the only measure with good interobserver reliability, whereas the other three of the four ratios were moderate. All measurements had excellent correlations for intraobserver reliability.

Conclusions

We postulate that a patient with a T-score <−1 for total paravertebral muscle area-to-VB area ratio at the L4 level is the most reliable method of all our measurements that can be used to diagnose a patient undergoing lumbar spine surgery with sarcopenia.

Association between beta-blocker use and obesity in Hong Kong Chinese elders: a post-hoc analysis

INTRODUCTION

Studies of Caucasian populations have shown that beta-blockers may exacerbate weight gain, a risk factor for many chronic diseases. Still, beta-blockers are the most prescribed antihypertensives in the Chinese population in Hong Kong. We aimed to explore the association between beta-blocker use, hypertension, and weight status of this population.

METHODS

A post-hoc analysis regarding body mass index (BMI) and the use of beta-blockers was performed based on the medication profile of community-dwelling older adults. Participants' BMI, hypertension diagnosis, name, dose, frequency, route of administration of beta-blockers, and other drugs that may alter body weight were recorded.

RESULTS

Of 1053 Chinese individuals aged ≥65 years (mean age 76.9±7.2 years, 80% female) from 32 elderly centres in Hong Kong, 18% (185/1053) of them consumed beta-blockers. That group also had a significantly larger proportion of obese individuals (45.9% vs 32.1%, P=0.002). After adjusting for other weight-altering drugs, beta-blockers remained a significant predictor of overweight and obesity (P=0.001). As the hypertensive population had significantly higher BMI than the normotensive population (24.3±3.6 vs 22.9±3.5, P<0.001), a sub-analysis on those with hypertension diagnosis confirmed that only the hypertensive population taking atenolol had a significantly larger population of obese individuals (BMI ≥25) compared with those who took metoprolol (58.9% vs 38.5%, P=0.03) and those who did not take any beta-blockers (58.9% vs 38.4%, P=0.007).

CONCLUSIONS

Our findings taken together with other guideline reservations cast doubt on whether beta-blockers, particularly atenolol, should be the major drug prescribed to older adults with hypertension.

Vaccine Protection against Multidrug-Resistant Klebsiella pneumoniae in a Nonhuman Primate Model of Severe Lower Respiratory Tract Infection

Klebsiella pneumoniae is a human gut communal organism and notorious opportunistic pathogen. The relative high burden of asymptomatic colonization by K. pneumoniae is often compounded by multidrug resistance-a potential problem for individuals with significant comorbidities or other risk factors for infection. A carbapenem-resistant K. pneumoniae strain classified as multilocus sequence type 258 (ST258) is widespread in the United States and is usually multidrug resistant. Thus, treatment of ST258 infections is often difficult. Inasmuch as new preventive and/or therapeutic measures are needed for treatment of such infections, we developed an ST258 pneumonia model in cynomolgus macaques and tested the ability of an ST258 capsule polysaccharide type 2 (CPS2) vaccine to moderate disease severity. Compared with sham-vaccinated animals, those vaccinated with ST258 CPS2 had significantly less disease as assessed by radiography 24 h after intrabronchial installation of 108 CFU of ST258. All macaques vaccinated with CPS2 ultimately developed ST258-specific antibodies that significantly enhanced serum bactericidal activity and killing of ST258 by macaque neutrophils ex vivo Consistent with a protective immune response to CPS2, transcripts encoding inflammatory mediators were increased in infected lung tissues obtained from CPS-vaccinated animals compared with control, sham-vaccinated macaques. Taken together, our data provide support for the idea that vaccination with ST258 CPS can be used to prevent or moderate infections caused by ST258. As with studies performed decades earlier, we propose that this prime-boost vaccination approach can be extended to include multiple capsule types.IMPORTANCE Multidrug-resistant bacteria continue to be a major problem worldwide, especially among individuals with significant comorbidities and other risk factors for infection. K. pneumoniae is among the leading causes of health care-associated infections, and the organism is often resistant to multiple classes of antibiotics. A carbapenem-resistant K. pneumoniae strain known as multilocus sequence type 258 (ST258) is the predominant carbapenem-resistant Enterobacteriaceae in the health care setting in the United States. Infections caused by ST258 are often difficult to treat and new prophylactic measures and therapeutic approaches are needed. To that end, we developed a lower respiratory tract infection model in cynomolgus macaques in which to test the ability of ST258 CPS to protect against severe ST258 infection.

1952. Bacteriophage Treatment Improves Survival of Mice Infected with Carbapenem-Resistant Klebsiella pneumoniae

Background

Bacteriophage (phage) therapy is being considered as a treatment option for patients with multi-drug-resistant bacterial infections. However, there is a dearth of controlled clinical data to support therapeutic phage efficacy. As a first step toward addressing this deficiency, we tested the ability of two well-characterized phages, alone and in combination, to kill carbapenem-resistant Klebsiella pneumoniae (ST258) in blood in vitro and rescue mice from lethal ST258 infection.

Methods

Wild-type C57BL/6J mice were infected with a lethal inoculum of ST258 by intra-peritoneal (IP) injection followed 1 hour later by IP administration of lytic phage P1, P2, or P1+P2 at a multiplicity of infection (MOI) estimated at 1. Survival of each group of mice was tracked for 10 days. In separate experiments, mice were sacrificed at 1 hour, 24 hours, and 48 hours post-phage treatment. Mouse blood and tissues were collected at each timepoint for enumeration of bacteria and phage, screening for phage resistance, and histopathology.

Results

ST258 survival in mouse blood in vitro was significantly less after 1 hour of incubation with P1 or P1+P2 (MOI 1) compared with the control group (no phage). Consistent with the in vitro data, none of the mice (0/15) in the control group (no phage) survived to 10 days post-infection, whereas 12/15, 14/15, and 15/15 mice survived in the P2, P1, and P1+P2-treated groups, respectively (P < 0.0001).

Conclusion

Prompt, systemic administration of lytic bacteriophages rescued mice from lethal ST258 infection. These data support the potential of phage therapy to effectively treat infections caused by ST258. It will be important to assess whether, for other phage-bacteria combinations, in vitro lysis in blood correlates with in vivo treatment efficacy and therefore may have predictive utility.

Disclosures

All Authors: No reported Disclosures.

P3760Temporal trends in stroke prevalence and its associations with changing patterns of antithrombotic regimens in patients with atrial fibrillation and a wide spectrum of coronary artery disease

Introduction

Much of the morbidity and mortality associated with atrial fibrillation (AF) is due to cerebrovascular thrombo-embolic complications such as ischemic stroke. Antithrombotic therapy is the fundamental treatment for many cardiovascular conditions, e.g. coronary artery disease (CAD), AF, and stroke to prevent thrombotic complications and death, but many patients have both CAD and AF. Dual antiplatelet therapy (DAPT) with acetylsalicylic acid (ASA) and a P2Y12 inhibitor has proven most effective in patients with recent myocardial infarction (MI) or after percutaneous coronary intervention (PCI), whereas for AF, oral anticoagulation (OAC) is most effective, with lesser efficacy but similar bleeding using DAPT. We investigated temporal trends in stroke prevalence and its associations with changing patterns of antithrombotic regimens in patients with non-valvular AF and a wide spectrum of co-incident CAD.

Methods

The Silesian TRiplE Antithrombotic Therapy (TREAT) Registry enrolled 14,873 patients with CAD from 2006 to 2014: 9,379 with stable CAD (SCAD), 1,460 with unstable angina (UA), 1,760 with NSTEMI and 2,328 with STEMI. We compared temporal trends in clinical features, an incidence of clinical events and patterns of antithrombotic regimens.

Results

2,194 of 14,873 patients (14.6%) had AF, including 74.1% with SCAD, 7.7% with UA, 10.1% with NSTEMI and 8.1% with STEMI. The AF prevalence increased from 11.2% in 2006 to 17.2% in 2014 which may be attributed to increasing age from 62.7 in 2006 to 67.8 in 2014. Overall, there was an increasing use of OAC therapy alone or with SAPT or DAPT from 46–50% in 2006–7 to 77–86%% in 2013–14. There was a steady increase in utilization of TREAT, and OAC ± SAPT throughout the study period (Panel A): after PCI there was a substantial increase in TREAT with a steady decline in DAPT (Panel B). The stroke rates declined throughout the study period from 3.3% in 2004 through a peak of 4.9% in 2011 to 1.1% in 2014. Conversely, bleeding rates increased from 6.0% to 10.5%.

Conclusions

There has been an increase followed by a progressive decline in stroke rate despite increasing age and AF prevalence in patients with both CAD and AF. This phenomenon is associated with a significant increase in the proportion of AF patients receiving guideline-recommended OAC therapy, driven by a steady increase in the utilization of triple antithrombotic therapy in patients following ACS or stent implantation and increase in OAC monotherapy in patients without ACS or stent implantation. This positive effect on stroke incidence is offset by increased bleeding risk, necessitating a closer look at the duration of triple therapy for ACS or PCI, and the long-term requirement for additional antiplatelet treatment in uncomplicated CAD.

P3769Rapid referral to a one-stop AF clinic following possible AF detection by community pharmacists leads to early diagnosis and appropriate anticoagulant treatment

Background

Atrial fibrillation is the most common cardiac arrhythmia globally, responsible for one third of ischaemic strokes, often resulting in death or incapacity. This condition, frequently asymptomatic is estimated to be up to 50% undiagnosed. Reducing this risk with appropriate detection and management strategies offers substantial economic and patient benefits. Community pharmacists have been shown to be an accessible healthcare professional capable of detecting atrial fibrillation. Concerns raised utilising community pharmacists is the additional workload for primary care physicians, and lack of a clear pathway to ensure patients are adequate followed with assurance of initiation of anticoagulation therapy.

Purpose

To assess the feasibility of screening by community pharmacists with onward referral to an innovative one-stop AF clinic to enable identification of new cases of AF and subsequent initiation of anticoagulation within 2 weeks.

Methods

21 pharmacies were recruited and trained on pathophysiology of AF and demonstration of pulse taking using pulse check and Kardia mobile device. Any person walking into a community pharmacy aged ≥65 years was offered a free pulse check. For any irregularity detected, individualised counselling was offered with a referral made to a one-stop AF clinic for confirmation and initiation of anticoagulation. Written patient consent was obtained.

Results

672 people were recruited with an average age of 69±3.5 years and 58% female (n=389). There was a history of hypertension in 618 (92%) and diabetes in 242 (36%), the most common co-morbidities. 45 people were referred following an irregular pulse or abnormal ECG rhythm strip, of whom 11 (1.6% of total population) had a confirmed AF diagnosis within 30 day follow up. An additional 8 cases with known AF not receiving anticoagulation termed (actionable AF) were also referred. All 19 cases of new or untreated AF were prescribed anticoagulation by the one stop clinic in accordance with guideline recommendations

Conclusions

ESC guidance recommends opportunistic screening for AF by pulse taking or ECG rhythm strip in patients ≥65 years of age. The 1.6% incidence of new AF was in accordance with meta-analyses identifying 1.4% of those aged ≥65 on a single time point check for presence of AF. Our model utilises the un-tapped skills of community pharmacy to deliver pulse checks of ECG rhythm recordings in an accessible primary care location with a clear referral pathway that is effective in early review and ensuring suitable patients receive anticoagulation. The innovative pathway could provide remote triage at scale and help address the missing people with undiagnosed and actionable AF by opening new channels for identification by healthcare professionals managing long term conditions who like pharmacists have not been considered suitable healthcare professionals due to lack of an established pathway for confirming the potential diagnosis of AF.

Acknowledgement/Funding

NHS England Test Bed Programme

P6537Screening for Atrial Fibrillation in Native Americans using iPhone ECG

Background

Atrial fibrillation (AF) is a major risk factor for stroke. Screening for silent AF, with subsequent initiation of anticoagulation in at-risk individuals, may decrease the risk of stroke. Native Americans (NA) have a high prevalence of diabetes and higher incidence of stroke than whites and blacks. Indigenous Australians, and Maori in New Zealand develop AF on average 10–20 years earlier than Europeans and Asians living in the same country. We hypothesized that screening for AF using a single time point, 30-second iPhone-based ECG recording will result in identification of silent AF in a significant number of NA compared to routine care, and that the age profile of those detected may be younger than non-NA.

Purpose

To determine the prevalence of AF, and incidence of unknown AF in NA seen at a tribal clinic using opportunistic screening with a single-lead iPhone-based ECG device (Kardia Mobile).

Methods

A database study was carried out in NA patients aged ≥50 followed to determine the prevalence of AF. Consecutive patients aged ≥50 with no prior history of AF were approached when attending the AST clinic for a primary care visit for opportunistic screening. Following consent, a 30-second ECG was recorded. A cardiologist overread all tracings to confirm the diagnosis of AF. Those confirmed to have AF were referred to a cardiologist for further management.

Results

The AF prevalence in 2952 NA patients aged ≥50 (1256 male, 1696 female), was 2.2%. Prevalence increased significantly with age (age 50–59, 0.9%; age 60–69, 2.6%; age 70–79, 3.6%; age ≥80, 7.8%; p for trend <0.0001). There were significant sex differences in AF prevalence (males 3.6% vs. females 1.2% p<0.0001). The mean age of those with AF was significantly older than for those without AF (69±10 vs, 63±6 respectively, p<0.0001). In the first month following study commencement in Jan 2019, 157 eligible patients without AF were approached and 142 (90%) agreed to receive screening for AF. The mean age of those enrolled was 62±8 years (66% women), and mean CHA2DS2-VASc score was 2.3±1.4.The age and sex distribution of those screened was similar to the overall clinic population without AF. Two of 142 patients (1.4%; age 59 and 61, respectively) screened were diagnosed with AF and were referred to a cardiologist. Enrollment is planned to reach 1500 patients by August 2019.

Conclusions

Opportunistic screening for AF using iPhone ECG in NA is feasible and well accepted by the patients when attending a tribal clinic. Our preliminary data suggest that NA, like other first nation peoples, may develop AF at a younger age compared to non-NA populations and would be likely to benefit from AF screening. In light of the high prevalence of risk factors for development of AF in NA, this novel approach for AF screening in tribal clinics has the potential to improve health outcomes among a large number of individuals.

Cervical and Thoracolumbar Spine Injury Evaluation, Transport, and Surgery in the Deployed Setting

This Cervical and Thoracolumbar Spine Injury Evaluation, Transport, and Surgery Clinical Practice Guideline (CPG) is designed to provide guidance to the deployed provider when they are treating a combat casualty who has sustained a spine or spinal cord injury. The CPG objective for the treatment and the movement of these patients is to maintain spinal stability through transport, perform decompression when urgently needed, achieve definitive stabilization when appropriate, avoid secondary injury, and prevent deterioration of the patient's neurological condition. Thorough and accurate documentation of the patient's neurological examination is crucial to ensure appropriate management decisions are made as the patient transits through the evacuation system. The use of this CPG should be in conjunction with good clinical judgment.

An empiric analysis of 5 counter measures against surgical site infections following spine surgery-a pragmatic approach and review of the literature

BACKGROUND CONTEXT

Surgical site infections (SSI) following spine surgery are debilitating complications to patients and costly to the healthcare system.

PURPOSE

Review the impact and cost effectiveness of 5 SSI prevention interventions on SSI rates in an orthopedic spine surgery practice at a major quaternary healthcare system over a 10-year period.

STUDY DESIGN

Retrospective observational study.

PATIENT SAMPLE

All of the surgical patients of the 5 spine surgeons in our department over a 10-year period were included in this study.

OUTCOME MEASURES

SSI rates per year, standardized infection ratios (SIR) for laminectomies and fusions during the most recent 3-year period, year of implementation, and frequency of use of the different interventions, cost of the techniques.

METHODS

The SSI prevention techniques described in this paper include application of intrawound vancomycin powder, wound irrigation with dilute betadine solution, preoperative chlorhexidine gluconate scrubs, preoperative screening with nasal swabbing, and decolonization of S. aureus, and perioperative antibiotic administration. Our institution's infection prevention and control data were analyzed for the yearly SSI rates for the orthopedic spine surgery department from 2006 to 2016. In addition, our orthopedic spine surgeons were polled to determine with what frequency and duration they have been using the different SSI prevention interventions.

RESULTS

SSI rates decreased from almost 6% per year the first year of observation to less than 2% per year in the final 6 years of this study. A SIR of less than 1.0 for each year was observed for laminectomies and fusions for the period from 2013 to 2016. All surgeons polled at our institution uniformly used perioperative antibiotics, Hibiclens scrub, and the nasal swab protocol since the implementation of these techniques. Some variability existed in the frequency and duration of betadine irrigation and application of vancomycin powder. A cost analysis demonstrated these methods to be nominal compared with the cost of treating a single SSI.

CONCLUSIONS

It is possible to reduce SSI rates in spine surgery with easy, safe, and cost-effective protocols, when implemented in a standardized manner.

Effect of teriparatide use on bone mineral density and spinal fusion: a narrative review of animal models

Purpose of the study: Teriparatide (Human recombinant Parathyroid Hormone 1-34) is an anabolic agent that is frequently used in patients with osteoporosis and has been extensively investigated with animal model and clinical studies in current literature. The purpose of the study was to evaluate the impact of teriparatide on bone mineral density and fusion. Materials and methods: The findings from preclinical studies that have investigated the role of teriparatide in animal models are summarized in presented review. Results: Overall, the studies show an improvement in bone mineral density and increased fusion rates for osteoporotic animals undergoing spine fusion with teriparatide use. Conclusion: Further studies should be conducted for unanswered questions, such as teriparatide use before surgery, the effect on cervical fusion and surgery related complications.

Postoperative Spine Infection: Diagnosis and Management

STUDY DESIGN

Review article.

OBJECTIVES

A review of the literature on postoperative spinal infections, their diagnosis, and management.

METHODS

A systematic computerized Medline literature search was performed using PubMed, Cochrane Database of Systematic Reviews, and EMBASE. The electronic databases were searched for publication dates from the last 10 years. The searches were performed from Medical Subject Headings (MeSH) used by the National Library of Medicine. Specifically, MeSH terms "spine," "infections," "management," and "diagnosis" were used.

RESULTS

Currently, the gold standard for diagnosis of postoperative spine infection is positive deep wound culture. Many of the current radiologic and laboratory tests can assist with the initial diagnosis and monitoring treatment response. Currently erythrocyte sedimentation rate, C-reactive protein, computed tomography scan, and magnetic resonance imaging with and without contrast are used in combination to establish diagnosis. Management of postoperative spine infection involves thorough surgical debridement and targeted antibiotic therapy.

CONCLUSIONS

Postoperative spine infection is a not uncommon complication following surgery that may have devastating consequences for a patient's short- and long-term health. A high index of suspicion is needed to make an early diagnosis.

Postoperative Seroma Formation After Posterior Cervical Fusion with Use of RhBMP-2: A Report of Two Cases

CASE

We present 2 cases of postoperative seroma formation following posterior cervical fusion with the use of recombinant human bone morphogenetic protein-2 (rhBMP-2).

CONCLUSION

Although some who advocate for the off-label use of rhBMP-2 in patients undergoing posterior cervical spine fusion believe it to be safe, relatively little has been published regarding complication rates. We believe that rhBMP-2 carries a risk of seroma formation in patients who undergo posterior cervical fusion, which necessitates the use of a postoperative drain. Surgeons should have a low threshold for obtaining postoperative magnetic resonance imaging in a symptomatic patient.

Does Recombinant Human Bone Morphogenic Protein 2 Affect Perioperative Blood Loss after Lumbar and Thoracic Spinal Fusion?

STUDY DESIGN

Retrospective cohort design.

PURPOSE

This study aimed to determine whether recombinant human bone morphogenic protein 2 (rhBMP-2) reduces total perioperative blood loss during lumbar and thoracic fusion.

OVERVIEW OF LITERATURE

Previous studies on rhBMP-2 versus iliac crest bone grafting in thoracic and lumbar fusions have yielded mixed results regarding reductions in blood loss and have largely neglected the postoperative period when analyzing total blood loss. Additionally, these studies have been limited by heterogeneity and sample size.

METHODS

We analyzed the blood loss patterns of 617 consecutive adult patients undergoing lumbar and/or thoracic fusions requiring subfascial drain placement at a single institution from January 2009 to December 2016. Patients were divided into BMP and non-BMP cohorts, and a propensity score analysis was conducted to account for the differences between cohorts.

RESULTS

At a per-level fused basis, the BMP group exhibited a significant reduction in the intraoperative (66.1 mL per-level fused basis; 95% confidence interval [CI], 127.9 to 4.25 mL; p =0.036) and total perioperative blood loss (100.7 mL per-level fused basis; 95% CI, 200.9 to 0.5 mL; p =0.049). However, no significant differences were observed in an analysis when not controlling for the number of levels or when examining the postoperative drain output.

CONCLUSIONS

RhBMP-2 appears to reduce both intraoperative and total blood loss during lumbar and thoracic fusions on a per-level fused basis. This total reduction in blood loss was achieved via intraoperative effects because RhBMP-2 had no significant effect on the postoperative drain output.

Continual near-infrared spectroscopy monitoring in the injured lower limb and acute compartment syndrome: an FDA-IDE trial

Aims

The aim of this study was to evaluate near-infrared spectroscopy (NIRS) as a continuous, non-invasive monitor for acute compartment syndrome (ACS).

Patients and Methods

NIRS sensors were placed on 86 patients with, and 23 without (controls), severe leg injury. NIRS values were recorded for up to 48 hours. Longitudinal data were analyzed using summary and graphical methods, bivariate comparisons, and multivariable multilevel modelling.

Results

Mean NIRS values in the anterior, lateral, superficial posterior, and deep posterior compartments were between 72% and 78% in injured legs, between 69% and 72% in uninjured legs, and between 71% and 73% in bilaterally uninjured legs. In patients without ACS, the values were typically > 3% higher in injured compartments. All seven limbs with ACS had at least one compartment where NIRS values were 3% or more below a reference uninjured control compartment. Missing data were encountered in many instances.

Conclusion

NIRS oximetry might be used to aid the assessment and management of patients with ACS. Sustained hyperaemia is consistent with the absence of ACS in injured legs. Loss of the hyperaemic differential warrants heightened surveillance. NIRS values in at least one injured compartment(s) were > 3% below the uninjured contralateral compartment(s) in all seven patients with ACS. Additional interventional studies are required to validate the use of NIRS for ACS monitoring. Cite this article: Bone Joint J 2018;100-B:787-97.

Antibody-Mediated Killing of Carbapenem-Resistant ST258 Klebsiella pneumoniae by Human Neutrophils

Carbapenem-resistant Klebsiella pneumoniae is a problem worldwide. A carbapenem-resistant K. pneumoniae lineage classified as multilocus sequence type 258 (ST258) is prominent in the health care setting in many regions of the world, including the United States. ST258 strains can be resistant to virtually all clinically useful antibiotics; treatment of infections caused by these organisms is difficult, and mortality is high. As a step toward promoting development of new therapeutics for ST258 infections, we tested the ability of rabbit antibodies specific for ST258 capsule polysaccharide to enhance human serum bactericidal activity and promote phagocytosis and killing of these bacteria by human neutrophils. We first demonstrated that an isogenic wzy deletion strain is significantly more susceptible to killing by human heparinized blood, serum, and neutrophils than a wild-type ST258 strain. Consistent with the importance of capsule as an immune evasion molecule, rabbit immune serum and purified IgG specific for ST258 capsule polysaccharide type 2 (CPS2) enhanced killing by human blood and serum in vitro Moreover, antibodies specific for CPS2 promoted phagocytosis and killing of ST258 by human neutrophils. Collectively, our findings suggest that ST258 CPS2 is a viable target for immunoprophylactics and/or therapeutics.IMPORTANCE Infections caused by carbapenem-resistant K. pneumoniae are difficult to treat, and mortality is high. New prophylactic approaches and/or therapeutic measures are needed to prevent or treat infections caused by these multidrug-resistant bacteria. A strain of carbapenem-resistant K. pneumoniae, classified by multilocus sequence typing as ST258, is present in many regions of the world and is the most prominent carbapenem-resistant K. pneumoniae lineage in the United States. Here we show that rabbit antibodies specific for capsule polysaccharide of ST258 significantly enhance human serum bactericidal activity and promote phagocytosis and killing of this pathogen by human neutrophils. These studies have provided strong support for the idea that development of an immunotherapy (vaccine) for carbapenem-resistant K. pneumoniae infections is feasible and has merit.