Editor's Choice - Comparison of Open Surgery and Endovascular Techniques for Juxtarenal and Complex Neck Aortic Aneurysms: The UK COMPlex AneurySm Study (UK-COMPASS) - Peri-operative and Midterm Outcomes

OBJECTIVE

Treatment of juxtarenal and complex neck abdominal aortic aneurysms (AAAs) is now commonly by endovascular rather than open surgical repair (OSR). Published comparisons show poor validity and scientific precision. UK-COMPASS is a comparative cohort study of endovascular treatments vs. OSR for patients with an AAA unsuitable for standard on label endovascular aneurysm repair (EVAR).

METHODS

All procedures for AAA in England (November 2017 to October 2019) were identified, AAA anatomy assessed in a Corelab, peri-operative risk scores determined, and propensity scoring used to identify patients suitable for either endovascular treatment or OSR. Patients were stratified by aneurysm neck length (0 - 4 mm, 5 - 9 mm, or ≥ 10 mm) and operative risk; the highest quartile was considered high risk and the remainder standard risk. Death was the primary outcome measure. Endovascular treatments included fenestrated EVAR (FEVAR) and off label standard EVAR (± adjuncts).

RESULTS

Among 8 994 patients, 2 757 had AAAs that were juxtarenal, short neck, or complex neck in morphology. Propensity score stratification and adjustment method comparisons included 1 916 patients. Widespread off label use of standard EVAR devices was noted (35.6% of patients). The adjusted peri-operative mortality rate was 2.9%, lower for EVAR (1.2%; p = .001) and FEVAR (2.2%; p = .001) than OSR (4.5%). In standard risk patients with a 0 - 4 mm neck, the mortality rate was 7.4% following OSR and 2.3% following FEVAR. Differences were smaller for patients with a neck length ≥ 5 mm: 2.1% OSR vs. 1.0% FEVAR. At 3.5 years of follow up, the overall mortality rate was 20.7% in the whole study population, higher following FEVAR (27.6%) and EVAR (25.2%) than after OSR (14.2%). However, in the 0 - 4 mm neck subgroup, overall survival remained equivalent. The aneurysm related mortality rate was equivalent between treatments, but re-intervention was more common after EVAR and FEVAR than OSR.

CONCLUSION

FEVAR proves notably safer than OSR in the peri-operative period for juxtarenal aneurysms (0 - 4 mm neck length), with comparable midterm survival. For patients with short neck (5 - 9 mm) and complex neck (≥ 10 mm) AAAs, overall survival was worse in endovascularly treated patients compared with OSR despite relative peri-operative safety. This warrants further research and a re-appraisal of the current clinical application of endovascular strategies, particularly in patients with poor general survival outlook owing to comorbidity and age.

Joint consensus statement on the vaccination of adult and paediatric haematopoietic stem cell transplant recipients: Prepared on behalf of the British society of blood and marrow transplantation and cellular therapy (BSBMTCT), the Children's cancer and Leukaemia Group (CCLG), and British Infection Association (BIA)

Haematopoietic stem cell transplant (HSCT) recipients have deficiencies in their adaptive immunity against vaccine preventable diseases. National and International guidance recommends that HSCT recipients are considered 'never vaccinated' and offered a comprehensive course of revaccination. This position statement aims to draw upon the current evidence base and existing guidelines, and align this with national vaccine availability and licensing considerations in order to recommend a pragmatic and standardised re-vaccination schedule for adult and paediatric HSCT recipients in the UK.

Editor's Choice - Comparison of Open, Standard, and Complex Endovascular Aortic Repair Treatments for Juxtarenal/Short Neck Aneurysms: A Systematic Review and Network Meta-Analysis

OBJECTIVE

Abdominal aortic aneurysms (AAAs) with adverse morphology of the aneurysm neck are "complex". Techniques employed to repair complex aneurysms include open surgical repair (OSR) and a number of on label endovascular techniques such as fenestrated endovascular aneurysm repair (FEVAR) and endovascular aneurysm repair (EVAR) with adjuncts (including chimneys and endo-anchors), as well as off label use of standard EVAR. The aim was to conduct a network meta-analysis (NMA) of published comparative outcomes.

DATA SOURCES

An electronic search was performed in Embase, MEDLINE, and the Cochrane Central Register of Controlled Trials (CENTRAL). These databases were interrogated using the PubMed interface and the Healthcare Databases Advanced Search (HDAS) interface developed by the National Institute of Health and Care Excellence.

REVIEW METHODS

Online databases were interrogated up to April 2020. Studies were included if they compared outcomes between at least two methods of repair for complex aneurysms (those with at least one adverse neck feature: absent/short neck, conicality, angulation, calcification, large diameter, and thrombus). The primary outcome measure was peri-operative death. Pre-registration was done in PROSPERO (CRD42020177482).

RESULTS

The search identified 24 observational studies and 7854 patients who underwent OSR, FEVAR, off label EVAR, or chimney EVAR. No comparative studies included EVAR with endo-anchors. NMA was performed on 23 studies that reported outcomes of aneurysms with short/absent infrarenal neck. Compared with OSR, off label EVAR (relative risk [RR] 0.10, 95% confidence interval [CI] 0.01 - 0.41) and FEVAR (RR 0.62, 95% CI 0.32-0.94) were associated with lower peri-operative mortality. This difference was not seen at the midterm follow up (30 months). Compared with OSR, FEVAR was associated with a lower peri-operative myocardial infarction (MI) rate (RR 0.37, 95% CI 0.16 - 0.62) but a higher midterm re-intervention rate (hazard ratio 1.65, 95% CI 1.04 - 2.66). All studies had a "moderate" or "high" risk of bias. Confidence in the network findings (GRADE) was generally "low".

CONCLUSION

This NMA demonstrated a peri-operative survival benefit for off label EVAR and FEVAR compared with OSR, potentially due to reduced risk of MI. FEVAR carries a greater midterm re-intervention risk than OSR, with potential implications for cost effectiveness. There is paucity of comparative data for cases with adverse neck features other than short length.

A risk-adjusted and anatomically stratified cohort comparison study of open surgery, endovascular techniques and medical management for juxtarenal aortic aneurysms-the UK COMPlex AneurySm Study (UK-COMPASS): a study protocol

INTRODUCTION

In one-third of all abdominal aortic aneurysms (AAAs), the aneurysm neck is short (juxtarenal) or shows other adverse anatomical features rendering operations more complex, hazardous and expensive. Surgical options include open surgical repair and endovascular aneurysm repair (EVAR) techniques including fenestrated EVAR, EVAR with adjuncts (chimneys/endoanchors) and off-label standard EVAR. The aim of the UK COMPlex AneurySm Study (UK-COMPASS) is to answer the research question identified by the National Institute for Health Research Health Technology Assessment (NIHR HTA) Programme: 'What is the clinical and cost-effectiveness of strategies for the management of juxtarenal AAA, including fenestrated endovascular repair?'

METHODS AND ANALYSIS

UK-COMPASS is a cohort study comparing clinical and cost-effectiveness of different strategies used to manage complex AAAs with stratification of physiological fitness and anatomical complexity, with statistical correction for baseline risk and indication biases. There are two data streams. First, a stream of routinely collected data from Hospital Episode Statistics and National Vascular Registry (NVR). Preoperative CT scans of all patients who underwent elective AAA repair in England between 1 November 2017 and 31 October 2019 are subjected to Corelab analysis to accurately identify and include every complex aneurysm treated. Second, a site-reported data stream regarding quality of life and treatment costs from prospectively recruited patients across England. Site recruitment also includes patients with complex aneurysms larger than 55 mm diameter in whom an operation is deferred (medical management). The primary outcome measure is perioperative all-cause mortality. Follow-up will be to a median of 5 years.

ETHICS AND DISSEMINATION

The study has received full regulatory approvals from a Research Ethics Committee, the Confidentiality Advisory Group and the Health Research Authority. Data sharing agreements are in place with National Health Service Digital and the NVR. Dissemination will be via NIHR HTA reporting, peer-reviewed journals and conferences.

TRIAL REGISTRATION NUMBER

ISRCTN85731188.

Characterising the incidence and mode of visceral stent failure after fenestrated endovascular aneurysm repair (FEVAR)

Background

In FEVAR, visceral stents provide continuity and maintain perfusion between the main body of the stent and the respective visceral artery. The aim of this study was to characterise the incidence and mode of visceral stent failure (type Ic endoleak, type IIIa endoleak, stenosis/kink, fracture, crush and occlusion) after FEVAR in a large cohort of patients at a high-volume centre.

Methods

A retrospective review of visceral stents placed during FEVAR over 15 years (February 2003-December 2018) was performed. Kaplan-Meier analyses of freedom from visceral stent-related complications were performed. The outcomes between graft configurations of varying complexity were compared, as were the outcomes of different stent types and different visceral vessels.

Results

Visceral stent complications occurred in 47/236 patients (19.9%) and 54/653 stents (8.3%). Median follow up was 3.7 years (IQR 1.7–5.3 years). There was no difference in visceral stent complication rate between renal, SMA and coeliac arteries. Visceral stent complications were more frequent in more complex grafts compared to less complex grafts. Visceral stent complications were more frequent in uncovered stents compared to covered stents. Visceral stent-related endoleaks (type Ic and type IIIa) occurred exclusively around renal artery stents. The most common modes of failure with SMA stents were kinking and fracture, whereas with coeliac artery stents it was external crush.

Conclusion

Visceral stent complications after FEVAR are common and merit continued and close long-term surveillance. The mode of visceral stent failure varies across the vessels in which the stents are located.

1097 Sleep Disturbances, Sleep Burden, And Depressive Symptoms In US Hispanics/Latinos: Results From The HCHS/SOL Sueño Study

Introduction

While sleep disturbances and depression often co-occur, these associations are understudied among Hispanics/Latinos. We examined the associations of sleep disturbances and sleep burden with depressive symptoms among Hispanic/Latino adults in the United States.

Methods

We used cross-sectional data from the Hispanic Community Health Study/Study of Latinos Sueño Ancillary study (2010-2013). The study enrolled 2072 adults (ages 18-64; 51.5% females) who completed one-week wrist-actigraphy and sleep questionnaires. Sleep burden was operationalized as the total count of sleep disturbances across six domains (duration, efficiency, midpoint, variability, insomnia, sleepiness). Depressive symptoms were assessed using the Center for Epidemiological Studies Depression scale (CESD-10). We used weighted survey linear regressions to evaluate the association of sleep disturbances and sleep burden with elevated depressive symptoms (CESD≥10) in individual models adjusted for age, gender, site, heritage, nativity, education, income, and employment. Sensitivity analyses further adjusted for behavioral health risk factors and apnea-hypopnea index.

Results

An estimated 28.3% had elevated depressive symptoms, 8.0% had short sleep duration (<6 hours of sleep), 10.9% had long sleep duration (>9 hours), 45.2% exhibited a later sleep midpoint (≥4:00AM), 38.4% had high sleep timing variability (upper third tertile for between day sleep midpoint), 15.3% had insomnia (ISI≥10), 17.3% had excessive daytime sleepiness (ESS ≥10), 21.5% had poor sleep efficiency (<85%), and 77.4% had a total sleep burden count of ≥0. Insomnia (ß=0.49,95%CI:.43,.56), later sleep timing (ß=0.10,95%CI:.04,.16), excessive daytime sleepiness (ß=0.19,95%CI:.11,.27), poor sleep efficiency (ß=0.09,95%CI:.02,.17), high variability (ß=0.07, 95%CI:.01,.12), and sleep burden (ß=0.11,95%CI:.09,.13), were each positively associated with elevated depressive symptoms in individual adjusted models and sensitivity analyses. Extreme sleep durations were not associated with elevated depressive symptoms.

Conclusion

Multiple inter-related sleep disturbances, particularly those pertaining to sleep quality and timing, are associated with depression and may be targets for future interventions aimed at improving mood among Hispanics/Latinos.

Support

HL127307, HL098927, HL125748

0357 CPAP Adherence is Lower in Minority Neighborhoods

Introduction

The effectiveness of continuous positive airway pressure (CPAP) in treating obstructive sleep apnea (OSA) is limited by adherence. Small, single-center studies have reported CPAP adherence is lower in racial minorities suggesting disparities in OSA care. We used nationally representative data to assess racial differences in CPAP adherence at a neighborhood level.

Methods

Telemonitoring data were obtained from a therapy database maintained by a CPAP manufacturer. Usage over the first 90 days in patients initiated on CPAP between 11/01/2015 and 10/31/2018 who had at least one usage session, age 18-90 years, and valid U.S. zip code were mapped to a zip code tabulation area (ZCTA). Age- and sex-adjusted CPAP usage was calculated for each ZCTA with greater than 10 CPAP users. Ecologic analyses were performed to model the association of the proportion of blacks and Hispanics in each ZCTA (obtained from the 2013-2017 American Community Survey) on CPAP usage controlling for proportion of adults with bachelor’s degree and proportion of adults with household income below the poverty line.

Results

Our analysis included 13,118 ZCTAs averaging data over 737,274 patients. In adjusted analyses, each 10% increase in the proportion of blacks and Hispanics was associated with a 0.12 (95% CI 0.11-0.12) hour and 0.14 (95% CI 0.14-0.15) hour decrease in nightly CPAP use, respectively. Mean usage in ZCTAs with <1%, 1-2.5%, 2.5-10%, 10-25%, and 25-100% blacks were 4.96, 4.81, 4.67, 4.56, and 4.14 hours respectively (p<0.001). Mean usage in ZCTAs with <1%, 1-2.5%, 2.5-10%, 10-25%, and 25-100% Hispanics were 4.87, 4.86, 4.75, 4.50, and 4.10 hours respectively (p<0.001).

Conclusion

CPAP adherence is lower in neighborhoods with higher proportions of black and Hispanic residents independent of differences in education or poverty. These differences lead to lower likelihood of meeting insurance coverage requirements for CPAP therapy, potentially exacerbating sleep health disparities.

Support

Philips Respironics, NIH R25HL130600 and K24HL127307.

0402 Impact of Various Actigraphic Editing Approaches on Sleep/Wake Outputs in Adults with Insomnia and Healthy Sleepers

Introduction

Actigraphy data can be edited using a variety of approaches. However, whether time-intensive manual editing provides different sleep/wake estimates compared to other approaches is unknown. The purpose of this study was to compare sleep/wake data obtained from a standardized editing approach that incorporates multiple inputs versus three other common approaches.

Methods

72 adults (33.8±11.1 y, 74% female, 71% white) provided 1022 nights of data for analysis; 45 were healthy sleepers (678 nights) and 27 met DSM-5 criteria for insomnia. Participants wore an Actiwatch Spectrum on their nondominant wrist and completed a sleep diary for 3-24 nights. Each night’s rest interval was set using four different approaches: (1) a standardized process based upon published guidelines (Patel et al., Sleep 2015) that incorporates a hierarchical order of multiple inputs (event marker, light, diary, activity; STANDARD); (2) software-provided automated algorithm (AUTO); (3) automated algorithm with incorporation of event markers (AUTOE); and (4) sleep diary (DIARY). We used linear mixed-effects models to evaluate whether sleep/wake parameters differed between the STANDARD and other editing approaches, accounting for patient status (healthy sleeper, insomnia) and the possibility that differences among editing approaches may be dependent on patient status.

Results

All results are expressed relative to the STANDARD approach. Bedtime was 36.1±5.1 min earlier (P<.0001) and morning out-of-bed time was 13.6±5.7 min later (P=.02) using the AUTO (P<.0001) approach. Time in bed was 42.3±4.7 min longer with AUTO (P<.0001). Sleep onset latency was 11.7±1.4 min and 2.8±1.4 min longer for AUTO (P<.0001) and DIARY (P=.05), respectively. Sleep duration was 22.5±4.4 min longer with AUTO (P<.0001). Wake after sleep onset was 6.8±1.2 min greater with AUTO (P<.0001). Similar patterns were observed for all sleep/wake measures among healthy sleepers and adults with insomnia.

Conclusion

A standardized approach to editing actigraphy data leads to different sleep/wake estimates compared to other common approaches, though the differences were often small in magnitude and not dependent upon sleep status. Most notably, reliance upon the automated algorithm yielded longer time in bed, sleep duration, sleep onset latency, and wake after sleep onset compared to the standardized approach.

Support

NIH K23HL118318

0677 Patient Preferences On Initiating Treatment With Continuous Positive Airway Pressure

Introduction

Clinical guidelines recommend continuous positive airway pressure (CPAP) therapy be initiated in patients with obstructive sleep apnea (OSA) either at home using an auto-titrating device or following manual titration in the sleep laboratory. Patient preference between these two options is unknown.

Methods

Patients newly prescribed CPAP therapy for the treatment of OSA at an academic sleep medicine clinic were surveyed by telephone within one month of initiating treatment. Data on demographics, disease severity and CPAP adherence were obtained from the medical record.

Results

A total of 75 participants (56% male, mean age 52±15 yrs, 48% moderate to severe OSA) were surveyed. Physicians prescribed home initiation of CPAP in 51%, lab initiation in 23%, and allowed the patient to choose in 27% of cases. Overall, 67% of participants (95% CI [56%-77%]) reported preference for home initiation. Preference for home initiation did not vary by age, sex, AHI, degree of sleepiness, or type of diagnostic study (home vs. lab sleep study) performed (p>0.10 for all). Convenience (44%) and starting treatment faster (44%) were the most common reasons provided for those favoring home initiation, while sleep technician availability (40%), optimization of pressure settings (32%), and ability to try multiple masks (28%) were cited by those favoring lab initiation. The prevalence of CPAP adherence at 90 days tended to be higher in those whose treatment was initiated aligned to preference (79% in those whose treatment initiation was concordant with preference vs. 64% in those whose treatment initiation was discordant, p=0.16).

Conclusion

Overall, two-thirds of patients with OSA prefer initiation of CPAP be done at home. This preference does not vary by demographics, OSA severity or diagnostic modality. Initiating treatment concordant with patient preference may lead to greater adherence.

Support

American Thoracic Society Academic Sleep Pulmonary Integrated Research/Clinical (ASPIRE) Fellowship, K24 HL127307

1144 Actigraphy-defined Sleep And Neurocognitive Decline In Middle-age Hispanic/Latino Adults

Introduction

Few studies have evaluated objective sleep measures and longitudinal neurocognitive decline, particularly in middle-age or Hispanic/Latino adults. We evaluated prospective associations between actigraphy-defined sleep and 7-year neurocognitive change among Hispanic/Latino adults. We hypothesized that sleep duration would be associated with neurocognitive decline.

Methods

We analyzed data from 1,036 adults 45-64 years of age from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL), a multi-center prospective cohort study of diverse community-dwelling Hispanic/Latino adults. At Visit 1 (2008-2011), participants underwent neurocognitive assessments, 7-days of actigraphy, home sleep testing, and sleep questionnaires (including the Insomnia Severity Index). Seven years later, participants repeated neurocognitive assessments. The neurocognitive battery included the Six-Item Screener, Brief Spanish-English Verbal Learning Test, phonemic word fluency test, and Digit Symbol Subtest. Survey linear regression was used to evaluate prospective associations between actigraphy-defined or self-reported sleep variables and neurocognitive change. Final models adjusted for objectively-defined variables (age, body-mass index, Field Center, and time between neurocognitive assessments), and self-reported variables (sex, education, Hispanic/Latino background, alcohol consumption, physical activity, heart failure, cerebrovascular events, depression and anxiety symptoms, and antidepressant use).

Results

At Visit 1, the sample was 55% female and mean age was 54.9±2.2 years. The mean sleep duration was 402.6±27.6 minutes, mean sleep-onset latency was 11.3±9.7 minutes, mean number of days with naps of ≥ 15 minutes duration was 1.1±0.7, and mean sleep-time per nap was 51±14.1 minutes. Increased sleep-onset latency was associated with 7-year declines in global neurocognitive function (β=-0.0026, p<0.01), verbal learning (β=-0.0028, p<0.001) and verbal memory (β=-0.036, p<0.05). Increased sleep-time per nap predicted better verbal memory (β=0.0038, p<0.05). In contrast, sleep duration, sleep fragmentation, and self-reported sleep measures were not associated with neurocognitive change.

Conclusion

Among middle-age adults, sleep-onset latency and nap duration were associated with neurocognitive change. These findings may serve as targets for intervention of neurocognitive decline.

Support

This work is supported by the National Institute on Aging: R01AG048642, RF1AG054548, R01AG061022, R21AG056952, and R21HL140437 (AR).

0609 Sleep Phenotypes in Middle-Aged and Older Hispanics/Latinos. Results from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL)

Introduction

Identifying sleep phenotypes in the diverse and understudied US Hispanic/Latino population is critical to developing interventions and mitigating distal clinical outcomes (e.g. dementias).

Methods

Using latent class analyses (LCA), we identify empirically derived and clinically meaningful sleep phenotypes using data on community dwelling middle-aged/older adults (ages ≥45-years) from the HCHS/SOL (2008-2011) - Investigation of Neurocognitive Aging (n=6,377). Sleep variables used included Apnea/Hypopnea Index (AHI), percent time SpO2<90%, Epworth Sleepiness Scale (ESS), Women’s Health Initiative Insomnia Rating Scale (WHIIRS), self-reported average sleep duration, restless legs symptoms, napping frequency, and sleep quality.

Results

Mean (M) age was 56.4±8.1 years, and 54.7% were female. Average AHI, ESS, WHIIRS, and sleep duration were 8.7±13.1, 6.0±5.0, 7.6±5.5, and 7.8±1.4, respectively, and 25.8% had zero percent time SpO2 <90%. Fit statistics indicated that a four-class solution provided the best data fit. The derived classes, adjusting for age, sex, income, and acculturation, corresponded with four clinically meaningful groups: (1) 28.8% were asymptomatic [(M) AHI=0.8; (M) ESS=5.6; (M)WHIIRS=7.6; (M) sleep duration=7.8; 0% SpO2<90%=74.1%], (2) 25.7 % were asymptomatic mild sleep apnea [(M) AHI=6.2; (M) ESS=3.8; (M) WHIIRS=2.9; (M) sleep duration=7.8; 0% SpO2<90%=8.8%], (3) 19.4% were symptomatic sleep apnea [(M) AHI=25.6; (M) ESS=8.5; (M) WHIIRS=7.2; (M) sleep duration=7.7; 0% SpO2<90%= 0.5%], and (4) 26.1% were insomnia [(M) AHI=5.7; (M) ESS=6.7; (M) WHIIRS=13.0; (M) sleep duration=7.8; 0% SpO2<90%=10.3%]. Classification into groups 3 and 4 were primarily driven by elevated AHI and WHIIRS scores, respectively. The distribution of scores in the derived groups suggest variations relative to current clinical thresholds.

Conclusion

We identified 4-groups using LCA in a community-based sample of diverse U.S. Hispanic/Latino adults. Better characterization of sleep phenotypes for Hispanics/Latinos can help in developing targeted interventions studies and ameliorate health disparities.

Support

5R01AG048642-05; R21AG056952; R21HL140437.

0607 Clinical Phenotypes of OSA in Diverse Hispanics/Latinos: Results from the Hispanic Community Health Study/Study of Latinos

Introduction

Recent work on US non-Latino Whites and Europeans from clinical samples used obstructive sleep apnea (OSA) symptoms to generate OSA phenotypes for individuals with moderate-severe OSA and proposed between 3-5 clusters. Validating these clusters in a diverse Hispanic/Latino community-based population with different biopsychosocial characteristics is crucial for early OSA identification and more personalized treatment.

Methods

This work is based on baseline data from The Hispanic Community Health Study/Study of Latinos (HCHS/SOL). HCHS/SOL is a prospective cohort study designed using a multisite (Bronx, NY, Chicago, IL, Miami, FL, San Diego, CA) multistage probability sample. The subpopulation of interest included adults 18-74 years (unweighted n=1,623) meeting criteria for moderate-severe OSA symptoms (≥15 Apnea-Hypopnea index (AHI) events per hour). We performed latent class analysis (LCA) using 15 common OSA symptoms to identify phenotype clusters.

Results

Average age was 52.4 ± 13.9 years and 34.1% were female. Mean AHI was 33.8 ± 22.5 events per hour. Fit statistics and clinical significance suggested that a three-class solution provided best fit to the data. The symptom profiles were consistent with (1) a Minimally Symptomatic group (46.8%), (2) a Disturbed Sleep group (38.1%), and (3) a Daytime Sleepiness group (15.1%). Validation analyses using alternative hierarchical and partitioning algorithms also suggested support for a three-class solution.

Conclusion

Sleep apnea phenotypes among diverse Hispanics/Latinos were consistent with recent findings from the Sleep Apnea Global Interdisciplinary Consortium. However, we found notable differences in the prevalence of these clusters relative to Whites. This suggests that other biopsychosocial factors may be contributing to OSA phenotypes among Hispanics/Latinos. Identification of OSA phenotypes in Hispanics/Latinos could inform better sleep interventions and therapeutics and help better align public health resources.

Support

5R01AG048642-05; R21AG056952; R21HL140437.

Mid-cervical interneuron networks following high cervical spinal cord injury

Spinal interneuron (IN) networks can facilitate respiratory motor recovery after spinal cord injury (SCI). We hypothesized that excitatory synaptic connectivity between INs located immediately caudal to unilateral cervical SCI would be most prevalent in a contra- to ipsilateral direction. Adult rats were studied following chronic C2 spinal cord hemisection (C2Hx) injury. Rats were anesthetized and ventilated and a multi-electrode array was used to simultaneously record INs on both sides of the C4-5 spinal cord. The temporal firing relationship between IN pairs was evaluated using cross-correlation with directionality of synaptic connections inferred based on electrode location. During baseline recordings, the majority of detectable excitatory IN connections occurred in a contra- to- ipsilateral direction. However, acute respiratory stimulation with hypoxia abolished this directionality, while simultaneously increasing the detectable inhibitory connections within the ipsilateral cord. We conclude that propriospinal networks caudal to SCI can display a contralateral-to-ipsilateral directionality of synaptic connections and that these connections are modulated by acute exposure to hypoxia.

A Systematic Review of Predictors of Reintervention After EVAR: Guidance for Risk-Stratified Surveillance

BACKGROUND

Current surveillance protocols after endovascular aneurysm repair (EVAR) are ineffective and costly. Stratifying surveillance by individual risk of reintervention requires an understanding of the factors involved in developing post-EVAR complications. This systematic review assessed risk factors for reintervention after EVAR and proposals for stratified surveillance.

METHODS

A systematic search according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was performed using EMBASE and MEDLINE databases to identify studies reporting on risk factors predicting reintervention after EVAR and proposals for stratified surveillance.

RESULTS

Twenty-nine studies reporting on 39 898 patients met the primary inclusion criteria for reporting predictors of reintervention or aortic complications with or without suggestions for stratified surveillance. Five secondary studies described external validation of risk scores for reintervention or aortic complications. There was great heterogeneity in reporting risk factors identified at the pre-EVAR, intraoperative, and post-EVAR stages of treatment, although large preoperative abdominal aortic aneurysm diameter was the most commonly observed risk factor for reintervention after EVAR.

CONCLUSION

Existing data on predictors of post-EVAR complications are generally of poor quality and largely derived from retrospective studies. Few studies describing suggestions for stratified surveillance have been subjected to external validation. There is a need to refine risk prediction for EVAR failure and to conduct prospective comparative studies of personalized surveillance with standard practice.

Coupling multielectrode array recordings with silver labeling of recording sites to study cervical spinal network connectivity

Midcervical spinal interneurons form a complex and diffuse network and may be involved in modulating phrenic motor output. The intent of the current work was to enable a better understanding of midcervical "network-level" connectivity by pairing the neurophysiological multielectrode array (MEA) data with histological verification of the recording locations. We first developed a method to deliver 100-nA currents to electroplate silver onto and subsequently deposit silver from electrode tips after obtaining midcervical (C3-C5) recordings using an MEA in anesthetized and ventilated adult rats. Spinal tissue was then fixed, harvested, and histologically processed to "develop" the deposited silver. Histological studies verified that the silver deposition method discretely labeled (50-μm resolution) spinal recording locations between laminae IV and X in cervical segments C3-C5. Using correlative techniques, we next tested the hypothesis that midcervical neuronal discharge patterns are temporally linked. Cross-correlation histograms produced few positive peaks (5.3%) in the range of 0-0.4 ms, but 21.4% of neuronal pairs had correlogram peaks with a lag of ≥0.6 ms. These results are consistent with synchronous discharge involving mono- and polysynaptic connections among midcervical neurons. We conclude that there is a high degree of synaptic connectivity in the midcervical spinal cord and that the silver-labeling method can reliably mark metal electrode recording sites and "map" interneuron populations, thereby providing a low-cost and effective tool for use in MEA experiments. We suggest that this method will be useful for further exploration of midcervical network connectivity.NEW & NOTEWORTHY We describe a method that reliably identifies the locations of multielectrode array (MEA) recording sites while preserving the surrounding tissue for immunohistochemistry. To our knowledge, this is the first cost-effective method to identify the anatomic locations of neuronal ensembles recorded with a MEA during acute preparations without the requirement of specialized array electrodes. In addition, evaluation of activity recorded from silver-labeled sites revealed a previously unappreciated degree of connectivity between midcervical interneurons.

Appearance of the Nellix endovascular aneurysm sealing system on computed tomography: implications for postoperative imaging surveillance

PURPOSE

To describe the imaging characteristics of the Nellix Endovascular Aneurysm Sealing (EVAS) System on serial computed tomography (CT) surveillance.

METHODS

Sixty-eight patients undergoing EVAS were enrolled in a surveillance protocol that included CT scans prior to hospital discharge and at 3, 6, and 9 months postoperatively. Images were analyzed for the presence of gas within the endobag, endoleak, and for maximum radiodensity measured in Hounsfield units (HU) within the uppermost, middle, and lowermost regions of each endobag.

RESULTS

Gas was seen within the endobags of all 68 EVAS repairs at the first postoperative CT compared with 2 (5.6%) of 36 undergoing the 3-month scan. The endobags appeared radiodense during initial imaging, and the median (interquartile range) radiodensity of the Nellix polymer decreased from 158.3 HU (149.5; 169.5) at the postoperative CT to 81.0 HU (74.0; 88.0) at 3 months, excluding 3 cases in which contrast pre-fill was utilized. Type I endoleak was seen at the periphery of the aneurysm sac or in the cleft between the endobags, with a substantially different appearance to endoleak after endovascular aneurysm repair.

CONCLUSION

The evolution of CT appearances after EVAS was characteristic and predictable. The device endobags were initially radiodense, which may impact the detection of endoleak within 3 months of EVAS. Endoleaks after EVAS were seen in a different anatomical area to endoleaks after conventional stent-graft repair.

Misdiagnosis of ruptured abdominal aortic aneurysm: systematic review and meta-analysis

PURPOSE

To quantitatively summarize the incidence of misdiagnosis of ruptured abdominal aortic aneurysms (rAAA), the most common presenting features, and the commonest incorrect differential diagnoses.

METHODS

A systematic search according to PRISMA guidelines was performed using EMBASE and MEDLINE databases to identify studies reporting the initial rate of misdiagnosis of patients with rAAA. Random-effects meta-analyses were performed to estimate the rate of misdiagnosis, presenting features, and commonest differential diagnoses. A sensitivity analysis was performed for studies reporting after 1990.

RESULTS

Nine studies comprising 1109 patients contributed to the pooled analysis, which found a 42% incidence of rAAA misdiagnosis (95% CI 29% to 55%). In studies reporting after 1990, misdiagnosis was seen in 32% (95% CI 16% to 49%). The most common erroneous differential diagnoses were ureteric colic and myocardial infarction. Abdominal pain, shock, and a pulsatile mass were presenting features in 61% (49%-72%), 46% (32%-61%), and 45% (29%-62%) of rAAAs, respectively.

CONCLUSION

The rate of misdiagnosis of rAAA has remained consistent over time and is concerning. There is a need for an effective clinical decision tool to enable accurate diagnosis and triage at the scene of the emergency.

A Systematic Review and Meta-analysis of Endovascular Popliteal Aneurysm Repair Using the Hemobahn/Viabahn Stent-Graft

Purpose: To perform an evidence synthesis study to assess outcomes of endovascular repair of popliteal artery aneurysms (PAAs) using the Hemobahn or Viabahn stent-graft. Methods: A systematic literature review was conducted conforming to established standards to identify articles published between 1996 (the date of introduction of the Hemobahn stent-graft) and 2013 reporting stent-graft repair of PAAs in at least 10 patients. The data were pooled for Kaplan-Meier analysis of primary and secondary patency rates [presented with 95% confidence intervals (CIs)] as the primary outcomes. Random effects meta-analysis was performed for secondary outcomes that included rates of reintervention, endoleak, stent-graft fracture, and limb salvage. Results: Fourteen studies reported outcomes for 514 PAAs. There was considerable heterogeneity in reporting standards among studies. Pooled primary and secondary patency rates were 69.4% (95% CI 63.3% to 76.2%) and 77.4% (95% CI 70.1% to 85.3%), respectively, at 5 years. Five studies (including only one randomized controlled trial) compared surgical to endovascular repair; no difference was found in primary patency on evidence synthesis (hazard ratio 1.30, 95% CI 0.79 to 12.14, p=0.189). Conclusion: Stent-graft repair provides a feasible treatment option for anatomically suitable PAAs. Further studies are required to optimize both patient selection and follow-up protocols.

A systematic review and meta-analysis indicates underreporting of renal dysfunction following endovascular aneurysm repair

Deterioration in renal function has been described after endovascular repair of abdominal aortic aneurysms (EVRs). The etiology is multifactorial and represents an important therapeutic target. A need exists to quantitatively summarize incidence and severity of renal dysfunction after EVR to allow better-informed attempts to preserve renal function and improve life expectancy. Here a systematic search was performed using Medline and Embase for renal function after EVR applying PRISMA statements. Univariate and multivariate random-effects meta-analyses were performed to estimate pooled postoperative changes in serum creatinine and creatinine clearance at four time points after EVR. Clinically relevant deterioration in renal function was also estimated at 1 year or more after EVR. Pooled probability of clinically relevant deterioration in renal function at 1 year or more was 18% (95% confidence interval of 14-23%, I2 of 82.5%). Serum creatinine increased after EVR by 0.05 mg/dl at 30 days/1 month, 0.09 mg/dl at 1 month to 1 year, and 0.11 mg/dl at 1 year or more (all significant). Creatinine clearance decreased after EVR by 5.65 ml/min at 1 month-1 year and by 6.58 ml/min at 1 year or more (both significant). Thus, renal dysfunction after EVR is common and merits attention.

The effect of hypercapnia on the sensitivity to flicker defined stimuli

BACKGROUND/AIMS

To investigate the effect of increased CO2 levels on flicker defined stimuli.

METHODS

The sensitivity of two flicker defined tasks was measured in nine healthy, trained observers using the Flicker Defined Form (FDF) stimulus of the Heidelberg Edge Perimeter (HEP; Heidelberg Engineering) and Frequency Doubling Technology (FDT) stimulus of the Matrix perimeter (Carl Zeiss Meditec) during normoxia and 15% hypercapnia (end-tidal CO2 increased by 15% relative to baseline). HEP-FDF and Matrix-FDT sensitivities were analysed for the global field, superior and inferior hemifields and at specific matched eccentricities, using repeated measures analysis of variance. The main effect of hypercapnia on flicker sensitivity was analysed using regression models.

RESULTS

Higher flicker sensitivity outcomes with increasing CO2 values were found for HEP-FDF and Matrix-FDT with a statistically significant main effect for HEP-FDF global, superior and inferior hemifields (p<0.01 for all) as well as 6°, 18°, 12° and 24° eccentricities (p=0.03, 0.04, 0.01, 0.05, respectively). When comparing mean sensitivity values between normocapnia and hypercapnia conditions, no statistically significantly different results were found for HEP-FDF and Matrix-FDT (p>0.05).

CONCLUSIONS

As CO2 levels were increased in healthy young individuals, there was an associated increase in visual sensitivity that was only significant for HEP-FDF stimuli, highlighting the different mechanisms involved in processing each of HEP-FDF and Matrix-FDT stimuli. Mean visual sensitivity outcomes were found to be similar for normocapnia and hypercapnia suggesting that a capability to compensate for a mild and stable increase in systemic CO2 levels may exist.

Helicobacter pylori downregulates expression of human β-defensin 1 in the gastric mucosa in a type IV secretion-dependent fashion

Helicobacter pylori establishes a chronic lifelong infection in the human gastric mucosa, which may lead to peptic ulcer disease or gastric adenocarcinoma. The human beta-defensins (hβDs) are antimicrobial peptides, hβD1 being constitutively expressed in the human stomach. We hypothesized that H. pylori may persist, in part, by downregulating gastric hβD1 expression. We measured hβD1 and hβD2 expression in vivo in relation to the presence, density and severity of H. pylori infection, investigated differential effects of H. pylori virulence factors, and studied underlying signalling mechanisms in vitro. Significantly lower hβD1 and higher hβD2 mRNA and protein concentrations were present in gastric biopsies from infected patients. Those patients with higher-level bacterial colonization and inflammation had significantly lower hβD1 expression, but there were no differences in hβD2. H. pylori infection of human gastric epithelial cell lines also downregulated hβD1. Using wild-type strains and isogenic mutants, we showed that a functionalcag pathogenicity island-encoded type IV secretion system induced this downregulation. Treatment with chemical inhibitors or siRNA revealed that H. pylori usurped NF-κB signalling to modulate hβD1 expression. These data indicate that H. pylori downregulates hβD1 expression via NF-κB signalling, and suggest that this may promote bacterial survival and persistence in the gastric niche.

Comparative efficacy of two standard methods for determination of iron and zinc in fruits, pulses and cereals

Micronutrients are essential elements needed in small amounts for adequate human nutrition and include the elements iron and zinc. Both of these minerals are essential to human well-being and an adequate supply of iron and zinc help to prevent iron deficiency anaemia and zinc deficiency, two prevalent health concerns of the developing world. The levels of zinc and, iron were measured in the Banana, Papaya, Rice, Finger millet, Soybean and Urdbean. Standard Atomic absorption spectroscopy (AAS) method was also applied to all the samples for zinc and iron analysis and compared with inductively coupled plasma mass spectroscopy (ICP-MS). It was observed that there was no matrix interference affecting the determination of both elements interested in all the samples analyzed. Average concentration relative standard deviation and standard deviation were used for the statistical evaluation of the results for both elements. Correlation coefficient was used as statistical model to compare both the techniques.

Prevention and management of graft thrombosis in pancreatic transplant

Pancreatic transplant effectively cures type 1 diabetes mellitus and maintains consistent long-term euglycemia. However, technical failure, and in particular graft thrombosis, accounts for the vast majority of transplants lost in the early postoperative period. The pancreas' inherently low microvascular flow state makes it vulnerable to vascular complications, as does the hypercoagulable blood of diabetic patients. Ultimately, the phenomenon is most definitely multifactorial. Prevention, as opposed to treatment, is key and should focus on reducing these multiple risk factors. This will involve tactical donor selection, optimal surgical technique and some form of anticoagulation. Close monitoring and early intervention will be crucial when treating thrombosis once preventative methods have failed. This may be achieved by further anticoagulation, graft salvage, or pancreatectomy with retransplant. This article will explore the multiple factors contributing to graft thrombus formation and the ways in which they may be addressed to firstly prevent, or more likely, reduce thrombosis. Secondly, we will consider the management strategies which can be implemented once thrombosis has occurred.

Reducing errors in combined open/endovascular arterial procedures: influence of a structured mental rehearsal before the endovascular phase

PURPOSE

To assess the incidence of errors before and after implementation of a structured mental rehearsal prior to the endovascular phase of combined open/endovascular arterial procedures.

METHODS

Over 6 weeks, 15 combined open/endovascular procedures (7 abdominal aorta and 8 thoracic aorta) lasting 58 hours were evaluated by a trained observer. In a blinded fashion, 2 individuals scrutinized event logs for errors, which were categorized by type, by potential to cause patient harm (danger), and by potential to disrupt the procedure (delay). After 9 procedures, a focus group-devised structured mental rehearsal was implemented prior to the endovascular phase for 6 combined procedures. Error patterns were compared before and after implementation. Data are expressed as median (range).

RESULTS

The error rate during the endovascular phase of the combined procedures was higher than the non-endovascular phase [7.64/hour (1.71-9.6) vs. 3.75/hour (1.71-5.54), respectively; p = 0.05]. Error rates during the endovascular phase were lower after the intervention compared to before [2.5/hour (1.4-6.0) vs. 7.6/hour (1.7-9.6), respectively; p = 0.05]. During the endovascular phase, danger and delay scores were also lower after the intervention [1.2/error (1.0-2.0) and 1.3/error (1.0-2.3), respectively] compared to before [1.75/error (1.4-2.5) and 2.0/error (1.3-2.5), respectively] (p = 0.036 and p = 0.036 for danger and delay, respectively).

CONCLUSION

A structured mental rehearsal before critical stages of procedures may reduce the rate and severity of intraoperative error.

Phase II Study of Paclitaxel in Patients With Soft Tissue Sarcomas

Purpose. Patients with soft tissue sarcoma (STS) who have previously received standard chemotherapy including adriamycin (doxorubicin), ifosfamide, cyclophosphamide and DTIC (dacarbazine) have very limited therapeutic options. It is important to identify new drugs with some activity in this disease and we therefore undertook this trial to determine the antitumor activity of paclitaxel (Taxol).Methods. We conducted a phase II study of paclitaxel in patients with STS who had received prior standard chemotherapy. Paclitaxel was administered at a starting dose of 200 mg m(-2) as a 24-h infusion with STS premedication, every 21 days or upon hematologic recovery (absolute granulocyte count (AGC) >/= 1500/mul, platelets >/= 100 000/mul). Neupogen was not used routinely. The study was conducted based on a two-stage design proposed by Simon. Responses were assessed radiographically using standard criteria.Results. Nineteen eligible patients were treated in the first stage of the study. The median age was 50 years (range 20-68 years), and there were nine females and 10 males with Zubrod performance status of 1 or 2. One patient achieved a minor response. Median AGC nadir was 0.1/mul on day 12 with absolute neutropenia lasting 5 days. Median platelet nadir was 171 000/mul on day 9. There were no grade 3/4 non-hematologic toxicities and no deaths related to treatment.Discussion. Paclitaxel, at this dose and schedule, is well tolerated but inactive in this patient population.

Identification of patient safety improvement targets in successful vascular and endovascular procedures: analysis of 251 hours of complex arterial surgery

OBJECTIVES

To investigate failures in patient safety for patients undergoing vascular and endovascular procedures to guide future quality and safety interventions.

DESIGN

Single centre prospective observational study.

METHODS

66 procedures (17 thoracoabdominal and 23 abdominal aortic aneurysms, 4 carotid and 22 limb procedures) were observed prospectively over a 9-month period (251 h operating time) by two trained observers. Event logs were recorded for each procedure. Two blinded experts identified and independently categorised failures into 22 types (using a validated category tool) and severity (5-point scale). Data are expressed as median (range). Statistical analysis was performed using Mann-Whitney U, Kruskal-Wallis and Spearman's Rank tests.

RESULTS

1145 failures were identified with good inter-assessor reliability (Cronbach's alpha 0.844). The commonest failure types related to equipment (including unavailability, configuration and other failures) (269/1145 [23.5%]) and communication (240/1145 [21.0%]). A comparatively lower number of technical and psychomotor failures were identified (103 [9.0%]). The number of failures correlated with procedure duration (rho = 0.695, p < 0.001) but not anatomical site of the procedure or pathology of the disease process. Failure rate was higher in patients undergoing combined surgical/endovascular procedures compared to open surgery (median 5.7/h [IQR 4.2-8.1] vs 3.0/h [2.5-3.5]; p < 0.001). The severity of failures was similar (1.5/5 [1-2] vs 1/5 [1-2] respectively; p = 0.095). For combined procedures, failure rates were significantly higher during the endovascular phase (9.6/h [7.5-13.7]) compared to the non-endovascular phase (3.0/h [1.0-5.0]; p < 0.001).

CONCLUSIONS

Failures in patient safety are common during complex arterial procedures. Few failures were severe, although minor failures during critical stages and accumulation of multiple minor failures may potentially be important. Failures occurred especially during the endovascular phase and were often related to equipment or communication aspects. Interventions to improve procedural safety and quality of care should primarily target these specific areas.

Providing skilled birth attendants and emergency obstetric care to the poor through partnership with private sector obstetricians in Gujarat, India

PROBLEM

India has the world's largest number of maternal deaths estimated at 117,000 per year. Past efforts to provide skilled birth attendants and emergency obstetric care in rural areas have not succeeded because obstetricians are not willing to be posted in government hospitals at subdistrict level.

APPROACH

We have documented an innovative public-private partnership scheme between the Government of Gujarat, in India, and private obstetricians practising in rural areas to provide delivery care to poor women.

LOCAL SETTING

In April 2007, the majority of poor women delivered their babies at home without skilled care.

RELEVANT CHANGES

More than 800 obstetricians joined the scheme and more than 176,000 poor women delivered in private facilities. We estimate that the coverage of deliveries among poor women under the scheme increased from 27% to 53% between April and October 2007. The programme is considered very successful and shows that these types of social health insurance programmes can be managed by the state health department without help from any insurance company or international donor.

LESSONS LEARNED

At least in some areas of India, it is possible to develop large-scale partnerships with the private sector to provide skilled birth attendants and emergency obstetric care to poor women at a relatively small cost. Poor women will take up the benefit of skilled delivery care rapidly, if they do not have to pay for it.

A polymorphism in the VKORC1 regulator calumenin predicts higher warfarin dose requirements in African Americans

Warfarin demonstrates a wide interindividual variability in response that is mediated partly by variants in cytochrome P450 2C9 (CYP2C9) and vitamin K 2,3-epoxide reductase complex subunit 1 (VKORC1). It is not known whether variants in calumenin (CALU) (vitamin K reductase regulator) have an influence on warfarin dose requirements. We resequenced CALU regions in a discovery cohort of dose outliers: patients with high (>90th percentile, n = 55) or low (<10th percentile, n = 53) warfarin dose requirements (after accounting for known genetic and nongenetic variables). One CALU variant, rs339097, was associated with high doses (P = 0.01). We validated this variant as a predictor of higher warfarin doses in two replication cohorts: (i) 496 patients of mixed ethnicity and (ii) 194 African-American patients. The G allele of rs339097 (the allele frequency was 0.14 in African Americans and 0.002 in Caucasians) was associated with the requirement for a 14.5% (SD +/- 7%) higher therapeutic dose (P = 0.03) in the first replication cohort and a higher-than-predicted dose in the second replication cohort (allele frequency 0.14, one-sided P = 0.03). CALU rs339097 A>G is associated with higher warfarin dose requirements, independent of known genetic and nongenetic predictors of warfarin dose in African Americans.

Genetic and clinical predictors of warfarin dose requirements in African Americans

The objective of this study was to determine whether, in African-American patients, additional vitamin K oxidoreductase complex subunit 1 (VKORC1), cytochrome P450 2C9 (CYP2C9), CYP4F2, or apolipoprotein E (APOE) polymorphisms contribute to variability in the warfarin maintenance dose beyond what is attributable to the CYP2C9*2 and *3 alleles and the VKORC1 -1639G>A genotype. In a cohort of 226 African-American patients, weekly warfarin dose requirements were lower in those with the CYP2C9*8 allele (34 (30-47) mg; P = 0.023) and the CYP2C9 *2, *3, *5, *6, or *11 allele (33(28-40 mg); P < 0.001) as compared with those with the CYP2C9*1/*1 genotype (43 (35-56) mg). The combination of CYP2C9 alleles, VKORC1 -1639G>A genotype, and clinical variables explained 36% of the interpatient variability in warfarin dose requirements. By comparison, a model without the CYP2C9*5, *6, *8, and *11 alleles explained 30% of the variability in dose. No other VKORC1, CYP4F2, or APOE polymorphism contributed to the variance. The inclusion of additional CYP2C9 variants may improve the predictive ability of warfarin dosing algorithms for African Americans.

Reduced sleep as an obesity risk factor

Poor sleep has increasingly gained attention as a potential contributor to the recent obesity epidemic. The increased prevalence of obesity in Western nations over the past half-century has been paralleled by a severe reduction in sleep duration. Physiological studies suggest reduced sleep may impact hormonal regulation of appetite. Prospective studies suggest reduced habitual sleep duration as assessed by self-report is an independent risk factor for an increased rate of weight gain and incident obesity. Cross-sectional studies have demonstrated that the association between reduced sleep and obesity persists when sleep habits are measured objectively, that the association is as a result of elevations in fat and not muscle mass and that this association is not related to sleep apnoea. Thus, reduced sleep appears to represent a novel, independent risk factor for increased weight gain. Further research is needed to determine whether interventions aimed at increasing sleep may be useful in combating obesity.

Using linkage analysis to identify quantitative trait loci for sleep apnea in relationship to body mass index

To understand the genetics of sleep apnea, we evaluated the relationship between the apnea hypopnea index (AHI) and body mass index (BMI) through linkage analysis to identify genetic loci that may influence AHI and BMI jointly and AHI independent of BMI. Haseman-Elston sibling regression was conducted on AHI, AHI adjusted for BMI and BMI in African-American and European-American pedigrees. A comparison of the magnitude of linkage peaks was used to assess the relationship between AHI and BMI. In EAs, the strongest evidence for linkage to AHI was on 6q23-25 and 10q24-q25, both decreasing after BMI adjustment, suggesting loci with pleiotropic effects. Also, a promising area of linkage to AHI but not BMI was observed on 6p11-q11 near the orexin-2 receptor, suggesting BMI independent pathways. In AAs the strongest evidence of linkage for AHI after adjusting for BMI was on chromosome 8p21.3 with linkage increasing after BMI adjustment and on 8q24.1 with linkage decreasing after BMI adjustment. Novel linkage peaks were also observed in AAs to both BMI and AHI on chromosome 13 near the serotonin-2a receptor. These analyses suggest genetic loci for sleep apnea that operate both independently of BMI and through BMI-related pathways.

Heritability of upper airway dimensions derived using acoustic pharyngometry

Acoustic pharyngometry represents a simple, quick noninvasive method of measuring upper airway dimensions, which are predictive of sleep apnoea risk. The aim of the present study was to assess the genetic basis of upper airway size as determined using pharyngometry. Participants in the Cleveland Family Study aged >14 yrs underwent three acoustic pharyngometric measurements. Variance component models adjusted for age and sex were used to estimate the heritability of pharyngometry-derived airway measures. A total of 568 out of 655 (87%) subjects provided pharyngometric curves of sufficient quality. Although African-Americans tended to show narrower airways compared with white subjects, heritability patterns were similar in these two groups. The minimum cross-sectional area exhibited a heritability of 0.34 in white subjects and 0.39 in African-Americans, suggesting that 30-40% of the total variance in this measure is explained by shared familial factors. Estimates were unchanged after adjustment for body mass index or neck circumference. In contrast, oropharyngeal length did not show significant heritability in either ethnic group. The minimum cross-sectional area of the oropharynx is a highly heritable trait, suggesting the presence of an underlying genetic basis. These findings demonstrate the potential utility of acoustic pharyngometry in dissecting the genetic basis of sleep apnoea.

Effect of increased lung volume on sleep disordered breathing in patients with sleep apnoea

BACKGROUND

Previous studies have shown that changes in lung volume influence upper airway size and resistance, particularly in patients with obstructive sleep apnoea (OSA), and that continuous positive airway pressure (CPAP) requirements decrease when the lung volume is increased. We sought to determine the effect of a constant lung volume increase on sleep disordered breathing during non-REM sleep.

METHODS

Twelve subjects with OSA were studied during non-REM sleep in a rigid head-out shell equipped with a positive/negative pressure attachment for manipulation of extrathoracic pressure. The increase in lung volume due to CPAP (at a therapeutic level) was determined with four magnetometer coils placed on the chest wall and abdomen. CPAP was then stopped and the subjects were studied for 1 hour in three conditions (in random order): (1) no treatment (baseline); (2) at "CPAP lung volume", with the increased lung volume being reproduced by negative extrathoracic pressure alone (lung volume 1, LV1); and (3) 500 ml above the CPAP lung volume(lung volume 2, LV2).

RESULTS

The mean (SE) apnoea/hypopnoea index (AHI) for baseline, LV1, and LV2, respectively, was 62.3 (10.2), 37.2 (5.0), and 31.2 (6.7) events per hour (p = 0.009); the 3% oxygen desaturation index was 43.0 (10.1), 16.1 (5.4), and 12.3 (5.3) events per hour (p = 0.002); and the mean oxygen saturation was 95.4 (0.3)%, 96.0 (0.2)%, 96.3 (0.3)%, respectively (p = 0.001).

CONCLUSION

An increase in lung volume causes a substantial decrease in sleep disordered breathing in patients with OSA during non-REM sleep.

Study of ground water quality for irrigation in some villages of Surat District, Gujarat (India)

40 ground water samples of 10 villages in Surat district, Gujarat (India) were analyzed for their suitability for irrigation purpose. The mean values of 4 samples taken from each village have been reported in the present study. Ground water of the study area was classified according to sodium adsorption ratio (SAR), percentage sodium (PS), residual sodium carbonate (RSC), Kelley's ratio and electrical conductivity. The value of sodium adsorption ratio indicated that majority of samples (9 out of 10) fall in low sodium hazard category. As per classification made by Wilcox (1948), on the basis of percentage sodium and electrical conductivity, only 1 sample (Vesu) not found suitable for irrigation purpose while only 1 sample (Gaviyar) found in good category. The remaining 8 samples were in good to permissible and permissible to doubtful category. Ground water was also classified according to the classification of United States Salinity Laboratory based on sodium and salinity hazard.