Building Pandemic-Resilient Primary Care Systems: Lessons Learned From COVID-19

On January 30, 2023, the Biden Administration announced its intention to end the existing COVID-19 public health emergency declaration. The transition to a "postpandemic" landscape presents a unique opportunity to sustain and strengthen pandemic-era changes in care delivery. With this in mind, we present 3 critical lessons learned from a primary care perspective during the COVID-19 pandemic. First, clinical workflows must support both in-person and internet-based care delivery. Second, the integration of asynchronous care delivery is critical. Third, planning for the future means planning for everyone, including those with potentially limited access to health care due to barriers in technology and communication. While these lessons are neither unique to primary care settings nor all-encompassing, they establish a grounded foundation on which to construct higher-quality, more resilient, and more equitable health systems.

Nursing Home PRevention of Injury in DEmentia (NH PRIDE): A pilot study of a remote injury prevention service for NH residents

BACKGROUND

Medication optimization, including prescription of osteoporosis medications and deprescribing medications associated with falls, may reduce injurious falls. Our objective was to describe a remote, injury prevention service (NH PRIDE) designed to optimize medication use in nursing homes (NHs), and to describe its implementation outcomes in a pilot study.

METHODS

This was a non-randomized trial (pilot study) including NH staff and residents from five facilities. Long-stay residents at high-risk for injurious falls were identified using a validated risk calculator and staff referral. A remote team reviewed the electronic health record (EHR) and provided recommendations as Injury Prevention Plans (IPP). A research nurse served as a care coordinator focused on resident engagement and shared decision-making. Outcomes included implementation measures, as identified in the EHR, and surveys and interviews with staff.

RESULTS

Across five facilities, 274 residents were screened for eligibility, and 46 residents (16.8%) were enrolled. Most residents were female (73.9%) and had dementia (63.0%). An IPP was completed for 45 residents (97.8%). The nurse made a total of 93 deprescribing recommendations in 36 residents (80% of residents had one or more deprescribing recommendation; mean 2.2 recommendations/resident). Twenty of 45 residents (44.4%) had a recommendation for osteoporosis treatment. Among residents with recommendations, 21/36 (58.3%) had one or more deprescribing orders written and 6/20 (30.0%) had an osteoporosis medication prescribed. At 4 months, most medication changes persisted. Adverse side effects were rare. Staff members identified several areas for program refinement, including aligning recommendations with provider workflow and engaging consultant psychiatrists.

CONCLUSIONS

A remote injury prevention service is safe and feasible to enhance deprescribing and osteoporosis treatment in long-stay NH residents at risk for injury. Additional investigation is needed to determine if this model could reduce injurious falls when deployed across NH chains.

Accumulation in Visceral Adipose Tissue Over 6 Years Is Associated With Lower Paraspinal Muscle Density

CONTEXT

Visceral adipose tissue (VAT) has been recognized to be a metabolically active fat depot that may have paracrine effects on surrounding tissues, including muscle. Since many adults accumulate VAT as they age, the effect of changes in VAT on muscle is of interest.

OBJECTIVE

We determined the association between 6-year changes in VAT and paraspinal muscle density, an indicator of fatty infiltration.

METHODS

This study included 1145 participants from the Framingham Study third-generation cohort who had both quantitative computed tomography scans of the spine at baseline and 6-year's follow-up, on whom muscle density was measured along with VAT. We implemented multiple regression to determine the association of muscle density at follow-up as primary outcome measure with changes in VAT (follow-up minus baseline divided by 100), adjusting for VAT at baseline, age, sex, height, menopausal status, presence of diabetes, and physical activity. Analyses were performed in men and women separately.

RESULTS

After adjustment for covariates, individuals with the greatest accumulation of VAT over 6 years had significantly lower paraspinal density at the follow-up with an estimated 0.302 (95% CI, -0.380 to -0.224) and 0.476 (95% CI: -0.598 to -0.354) lower muscle density (HU) per 100-cm3 increase in VAT (both P values < .001) in men and women, respectively.

CONCLUSION

These results highlight that age-related accumulation of VAT in men and women is associated with lower muscle density. VAT may represent a modifiable risk factor for poor musculoskeletal outcomes with aging.

Early-Life Exposure of Pigs to Topsoil Alters miRNA and mRNA Expression in Peripheral Blood Mononuclear Cells

Exposure to less-hygienic conditions during early childhood has been associated with stimulation and development of the immune system. A recent study indicated that exposure of piglets to soil-borne microbes during lactation was related with modulation of gut microbiota and immune function. To identify the potential molecular mechanisms and pathways impacted by early-life topsoil exposure, we analyzed the messenger RNA (mRNA) and micro-RNA (miRNA) expression in peripheral blood mononuclear cells (PBMCs) from these piglets. Total RNA was extracted from the PBMCs of piglets exposed to topsoil only from d 4–d 21 of life (mRNA n = 6; miRNA n = 5) or unexposed control pigs (mRNA n = 6; miRNA n = 8) at 11, 20, and 56 days of age. Small RNA and mRNA were sequenced with 50-bp single-end reads using Illumina chemistry. Sequence data were quality checked with FASTQC software and aligned to the Sscrofa 11.1 genome with the STAR aligner for mRNA and mirDeep2 for miRNA. Differential expression (DE) analysis was performed using PROC Glimmix of SAS to evaluate changes in expression due to topsoil exposure over time with genes declared DE at a false discovery rate (FDR) of q &lt; 0.10. A total of 138 mRNA and 21 miRNAs were identified as DE for the treatment by age interaction. Ontology enrichment analysis of DE mRNA revealed Gene ontology (GO) terms directly involved in the connection between T-cell and antigen-presenting cells that are associated with T-cell activation. Key regulatory genes identified include PTPRJ, ITGB3, TRBV30, CD3D, mir-143, mir-29, and mir-148a. While these results require validation, this study provides data supporting the hypothesis that less-hygienic environments during early life may contribute to the development of the immune system.

Increased Clinician Time Using Electronic Health Records During COVID-19 Pandemic

The COVID-19 pandemic challenged how healthcare systems provided care in socially distanced formats. We hypothesized that the COVID-19 era changes in clinical care delivery models contributed to increased Electronic Health Record (EHR) related work. To evaluate the changes in time and volume metrics of EHR usage, we segregated EHR audit log metric data into PreCOVID2019 March/April/May, initial COVID2020 March/April/May, and late COVID2021 March/April/May for 1262 physician providers. We discovered significant and pragmatically meaningful increases in total average time providers spent in the EHR in minutes mean(SD) PreCOVID2019=1958(1576), Mid-COVID2020=1709(1473), Late-COVID2021=2007(1563). Differences in total time in the EHR were significant Pre-mid:p-value=<0.001, but not Pre-Late:p=0.439. Total number of messages received across all specialties increased significantly mean(SD) PreCOVID=459(389), MidCOVID=400(362), LateCOVID 521(423) Pre-Mid p-value=<0.001 and Pre-Late p-value=<0.001. We additionally found changes in total time to differ significantly across select specialties. Based on these findings we recommend further assessment of physician workload and how new factors such as telehealth are contributing to EHR usage.

The Trial to Reduce Antimicrobial Use in Nursing Home Residents With Alzheimer Disease and Other Dementias (TRAIN-AD): A Cluster Randomized Clinical Trial

IMPORTANCE

Antimicrobials are extensively prescribed to nursing home residents with advanced dementia, often without evidence of infection or consideration of the goals of care.

OBJECTIVE

To test the effectiveness of a multicomponent intervention to improve the management of suspected urinary tract infections (UTIs) and lower respiratory infections (LRIs) for nursing home residents with advanced dementia.

DESIGN, SETTING, AND PARTICIPANTS

A cluster randomized clinical trial of 28 Boston-area nursing homes (14 per arm) and 426 residents with advanced dementia (intervention arm, 199 residents; control arm, 227 residents) was conducted from August 1, 2017, to April 30, 2020.

INTERVENTIONS

The intervention content integrated best practices from infectious diseases and palliative care for management of suspected UTIs and LRIs in residents with advanced dementia. Components targeting nursing home practitioners (physicians, physician assistants, nurse practitioners, and nurses) included an in-person seminar, an online course, management algorithms (posters, pocket cards), communication tips (pocket cards), and feedback reports on prescribing of antimicrobials. The residents' health care proxies received a booklet about infections in advanced dementia. Nursing homes in the control arm continued routine care.

MAIN OUTCOMES AND MEASURES

The primary outcome was antimicrobial treatment courses for suspected UTIs or LRIs per person-year. Outcomes were measured for as many as 12 months. Secondary outcomes were antimicrobial courses for suspected UTIs and LRIs when minimal criteria for treatment were absent per person-year and burdensome procedures used to manage these episodes (bladder catherization, chest radiography, venous blood sampling, or hospital transfer) per person-year.

RESULTS

The intervention arm had 199 residents (mean [SD] age, 87.7 [8.0] years; 163 [81.9%] women; 36 [18.1%] men), of which 163 (81.9%) were White and 27 (13.6%) were Black. The control arm had 227 residents (mean [SD] age, 85.3 [8.6] years; 190 [83.7%] women; 37 [16.3%] men), of which 200 (88.1%) were White and 22 (9.7%) were Black. There was a 33% (nonsignificant) reduction in antimicrobial treatment courses for suspected UTIs or LRIs per person-year in the intervention vs control arm (adjusted marginal rate difference, -0.27 [95% CI, -0.71 to 0.17]). This reduction was primarily attributable to reduced antimicrobial use for LRIs. The following secondary outcomes did not differ significantly between arms: antimicrobials initiated when minimal criteria were absent, bladder catheterizations, venous blood sampling, and hospital transfers. Chest radiography use was significantly lower in the intervention arm (adjusted marginal rate difference, -0.56 [95% CI, -1.10 to -0.03]). In-person or online training was completed by 88% of the targeted nursing home practitioners.

CONCLUSIONS AND RELEVANCE

This cluster randomized clinical trial found that despite high adherence to the training, a multicomponent intervention promoting goal-directed care for suspected UTIs and LRIs did not significantly reduce antimicrobial use among nursing home residents with advanced dementia.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03244917.

An advance care planning long-term care initiative in response to COVID-19

Objective

Describe a systematic approach to address advance care planning (ACP) during a COVID‐19 outbreak and its impact on the incidence of new do‐not‐hospitalize (DNH) directives among long‐term care (LTC) residents.

Design

Prospective quality improvement initiative.

Setting

Two long‐term chronic care campuses within a large academic healthcare organization.

Participants

LTC residents with activated healthcare proxies who lacked DNH directives based on documentation in the electronic medical record (EMR) as of April 13, 2020.

Intervention

Using a structured discussion guide, trained healthcare staff from various disciplines contacted the residents' proxies to conduct COVID‐19 focused ACP discussions. Residents without DNH directives with COVID‐19 were prioritized. Preferences ascertained in the discussion were communicated to the residents' primary care teams and directives were updated in the EMR accordingly.

Measurements

Residents who acquired a new DNH directive during the study initiative were determined using the EMR. Subsequent changes in DNH orders, hospitalizations, and deaths were ascertained by retrospective chart review from the date of new DNH through August 5, 2020.

Results

At baseline, 315/581 (54%) of LTC residents did not have a DNH directive. Their mean age was 87 (±9) years and 70% were female. Following ACP discussions, 124/315 (39%) of residents acquired a new DNH directive. Among residents with new DNH directives, 65/124 (52%) were diagnosed with COVID‐19 from April 2, 2020 to May 21, 2020. During follow‐up, only 6/124 (4.8%) residents had their DNH order reversed, 2/124 (1.6%) residents were hospitalized with illnesses unrelated to COVID‐19, and 29/124 (23%) died.

Conclusions

There was substantial opportunity to increase the proportion of LTC residents with DNH orders during the COVID‐19 pandemic through a systematic ACP initiative which utilized real‐time EMR data. New directives to avoid hospitalizations were sustained among the majority of residents beyond the peak of the pandemic.

The Impact of Tai Chi Exercise on Health Care Utilization and Imputed Cost in Residents of Low-Income Senior Housing

BACKGROUND/OBJECTIVES

This study was designed to test the impact of Tai Chi (TC) on healthcare utilization and cost in older adults living in low-income senior housing. We hypothesized that TC would improve overall health enough to reduce the use of emergency department (ED) and inpatient services.

DESIGN

Cluster randomized controlled trial with randomization at the housing site level.

SETTING

Greater Boston, Massachusetts.

PARTICIPANTS

The study includes 6 sites with 75 individuals in the TC treatment condition and 6 sites with 67 individuals in the health education control condition.

INTERVENTION

Members of the treatment group received up to a year-long intervention with twice weekly, in-person TC exercise sessions along with video-directed exercises that could be done independently at home. The comparison group received monthly, in-person healthy aging education classes (HE). Study recruitment took place between August, 2015 and October, 2017. Key outcomes included acute care utilization (inpatient stays, observation stays and emergency department visits). In addition, the cost of utilization was estimated using the age, sex and race adjusted allowed amount from Medicare claims for a geographically similar population aged ≥ 65.

RESULTS

The results suggested a possible reduction in the rate of ED visits in the TC group vs. controls (rate ratio = 0.476, p-value = 0.06), but no findings achieved statistical significance. Adjusted estimates of imputed costs of ED and hospital care were similar between TC and HE, averaging approximately $3,000 in each group.

CONCLUSION

ED utilization tended to be lower over 6 to 12 months of TC exercises compared to HE in older adults living in low-income housing, although estimated costs of care were similar.

Efficacy of HLA-compatible Platelet Transfusion for Patients with Acute Myeloid Leukemia Refractory to Platelet Transfusion

Introduction/Objective

Acute myeloid leukemia (AML) patients often require transfusion support during induction chemotherapy. Platelet transfusion refractoriness (PTR) may develop due to HLA alloimmunization. Management of immune-refractory patients with HLA-compatible platelet transfusions is labor intensive and associated with increased costs. The purpose of this study is to evaluate the efficacy of HLA-compatible platelet units in AML patients.

Methods

Newly diagnosed AML patients undergoing induction chemotherapy in our institute between 2015 and 2018 were identified. Platelet counts and platelet transfusion data from initiation of chemotherapy until platelet recovery (&gt; 20K/µL and increased consistently) were extracted. A 24-hour posttransfusion corrected count increment (CCI) was calculated to evaluate the efficacy of each platelet transfusion. PTR was declared if a patient had a 24-hour CCI &lt; 4K following two consecutive transfusions. Student’s t-test was used for statistical analysis. Results were presented as mean ± SE, * if p &lt; 0.05.

Results

We identified 39 patients with newly diagnosed AML. PTR developed in 22/39 (56%) patients during induction chemotherapy. The average CCI was higher among those without PTR compared to those with PTR (8,408 ± 585 vs. 2,923 ± 360*), and overall platelet transfusion burden (in number of units) was lower (7.29 ± 1.0 vs. 18.55 ± 1.71*). HLA antibodies were identified in 3/22 (14%) PTR patients, as 6/22 (27%) were tested. The average CCI during HLA matched transfusions for these 3 patients was higher than that with random units (2,059 ± 149 vs. -126 ± 306*). Compared to HLA-negative PTR patients receiving random units, the average CCI for HLA-compatible transfusions was still lower, though not significantly (2,059 ± 149 vs. 3,099 ± 390, p = 0.33), while the number of HLA- compatible units transfused was significantly higher (31.0 ± 3.0 vs. 16.6 ± 1.45*).

Conclusion

In a cohort of newly diagnosed AML patients undergoing induction chemotherapy whose PTR was associated with detectable HLA antibodies, transfusion support with HLA-matched products did not lead to reduced overall platelet transfusion rates and CCI remains in the refractory range. This suggests that use of HLA matched platelets among newly diagnosed AML patients with PTR, even in the setting of detectable HLA antibodies, does not appear to result in reduced overall product utilization.

The trial to reduce antimicrobial use in nursing home residents with Alzheimer's disease and other dementias: study protocol for a cluster randomized controlled trial

BACKGROUND

Infections are common in nursing home (NH) residents with advanced dementia but are often managed inappropriately. Antimicrobials are extensively prescribed, but frequently with insufficient evidence to support a bacterial infection, promoting the emergence of multidrug-resistant organisms. Moreover, the benefits of antimicrobials remain unclear in these seriously ill residents for whom comfort is often the goal of care. Prior NH infection management interventions evaluated in randomized clinical trials (RCTs) did not consider patient preferences and lack evidence to support their effectiveness in 'real-world' practice.

METHODS

This report presents the rationale and methodology of TRAIN-AD (Trial to reduce antimicrobial use in nursing home residents with Alzheimer's disease and other dementias), a parallel group, cluster RCT evaluating a multicomponent intervention to improve infection management for suspected urinary tract infections (UTIs) and lower respiratory tract infections (LRIs) among NH residents with advanced dementia. TRAIN-AD is being conducted in 28 facilities in the Boston, USA, area randomized in waves using minimization to achieve a balance on key characteristics (N = 14 facilities/arm). The involvement of the facilities includes a 3-month start-up period and a 24-month implementation/data collection phase. Residents are enrolled during the first 12 months of the 24-month implementation period and followed for up to 12 months. Individual consent is waived, thus almost all eligible residents are enrolled (target sample size, N = 410). The intervention integrates infectious disease and palliative care principles and includes provider training delivered through multiple modalities (in-person seminar, online course, management algorithms, and prescribing feedback) and an information booklet for families. Control facilities employ usual care. The primary outcome, abstracted from the residents' charts, is the number of antimicrobial courses prescribed for UTIs and LRIs per person-year alive.

DISCUSSION

TRAIN-AD is the first cluster RCT testing a multicomponent intervention to improve infection management in NH residents with advanced dementia. Its findings will provide an evidence base to support the benefit of a program addressing the critical clinical and public health problem of antimicrobial misuse in these seriously ill residents. Moreover, its hybrid efficacy-effectiveness design will inform the future conduct of cluster RCTs evaluating nonpharmacological interventions in the complex NH setting in a way that is both internally valid and adaptable to the 'real-world'.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03244917 . Registered on 10 August 2017.

A Cluster Randomized Trial of Tai Chi vs Health Education in Subsidized Housing: The MI-WiSH Study

OBJECTIVES

Tai Chi (TC) may benefit older adults with a variety of diseases and disabilities. We tested the hypothesis that TC improves physical function in older adults living in low-income housing facilities.

DESIGN

Cluster randomized controlled trial.

SETTING

Subsidized housing facilities in Boston, Massachusetts, and neighboring communities.

PARTICIPANTS

Volunteers were recruited from 15 facilities. The 180 randomized participants were 60 years of age or older, able to understand English and participate in TC, expected to remain in the facility for 1 year, and able to walk independently.

INTERVENTION

TC classes were conducted in the housing facilities twice/week for 1 year and compared with monthly health promotion educational classes and social calls.

MEASUREMENTS

The primary outcome was physical function measured by the Short Physical Performance Battery (SPPB). Secondary outcomes included other aspects of physical and cognitive function, and falls.

RESULTS

An interim analysis revealed less improvement over 12 months in SPPB scores among TC participants (+.20 units; 95% confidence interval [CI] = -.20 to +.60; P = .69) vs control participants (+.51 units; 95% CI = +.15 to +.87; P = .007), a difference of -.31 units (95% CI = -.66 to .04; P = .082). This met the criterion for futility, and the Data Safety Monitoring Board recommended trial termination. No differences were found in 6- or 12-month changes favoring TC in any secondary outcomes or adverse events.

CONCLUSION

In older adults with multiple chronic conditions living in subsidized housing facilities, 6 and 12 months of twice/week TC classes were not associated with improvements in functional health. J Am Geriatr Soc 67:1812-1819, 2019.

Contrasting lengths of Pelargonium floral nectar tubes result from late differences in rate and duration of growth

BACKGROUND AND AIMS

Much of morphological evolution in flowers has arisen from pollinator-mediated selection, often manifest as a match between the length of the pollinator's proboscis and the depth of tubular corollas or spurs. We investigate development, growth and homology of the unique nectar tube of Pelargonium, frequently described as 'a spur adnate to the pedicel'.

METHODS

We focused on two species. The nectar tube of P. ionidiflorum is three times longer than that of P. odoratissimum. Light and scanning electron microscopy were carried out, and daily growth measurements were used to compare nectar tube development and vascular patterns.

KEY RESULTS

Nectar tubes in both species are initiated centripetally to the dorsal sepal in a space created by lateral displacement of two antepetalous stamens. The cavity deepens through subsequent intercalary growth of the receptacle that proceeds at the same rate in both species until tubes reach approx. 10 mm in length. Differences in final nectar tube lengths arise via an increase in the rate and duration of growth of the receptacle that begins just before anthesis (floral opening) and continues for several days past anthesis in P. ionidiflorum but does not occur in P. odoratissimum. Epidermal cells of the dorsal surface of the nectar tube in P. ionidiflorum are approx. 1.6 times longer than those in P. odoratissimum. Histological sections show no evidence that the nectar tube is a spur that became evolutionarily fused to the pedicel.

CONCLUSIONS

Nectar tubes in Pelargonium are localized cavities that form in the receptacle via intercalary growth. Differences in the rate and duration of growth just prior to and following anthesis underlie differences in final tube lengths. Because differences in cell lengths do not fully account for differences in nectar tube lengths, evolutionary diversification must involve changes in both cell cycle and cell expansion.

Frailty, Physical Activity, and Mobility in Patients With Cardiac Implantable Electrical Devices

Background

This study aimed to demonstrate the feasibility of measuring frailty in patients with cardiac implantable electrical devices while validating the physiologic significance of device‐detected physical activity by evaluating its association with frailty and mobility.

Methods and Results

Outpatients with cardiac implantable electrical devices compatible with physical activity analysis with at least 7 days of data were eligible. Office testing included frailty status (Study of Osteoporotic Fractures instrument), gait speed (m/s), mobility according to the Timed Up and Go (TUG) test (seconds), and daily physical activity (h/d) as measured by cardiac implantable electrical device. Among 219 patients, Study of Osteoporotic Fractures testing found 39.7% to be robust, 47.5% prefrail, and 12.8% frail. The mean gait speed for the cohort was 0.8±0.3 m/s, mean TUG time was 10.9±4.4 seconds, and mean activity was 2.8±1.9 h/d. Frail patients were markedly more likely to have gait speeds <0.8 m/s (OR 6.25, 95% CI 1.79‐33.3). In unadjusted analyses each 1‐hour increase in mean daily activity was associated with a 46% reduction of frail phenotype (OR 0.54, 95% CI 0.40‐0.74) versus robust and with a 27% reduction in the odds of having the prefrail phenotype (OR 0.73, 95% CI 0.62‐0.86). After adjustment this association per hour of activity persisted, with an adjusted OR for frailty of 0.71 (95% CI 0.51‐0.99) and adjusted OR for prefrailty of 0.81 (95% CI 0.67‐0.99).

Conclusions

Frailty and mobility limitation are common among cardiac implantable electrical device patients and are correlated to device‐detected physical activity.

Degenerative effects of cobalt-chloride treatment on neurons and microglia in a porcine retina organ culture model

In order to understand the pathological processes of retinal diseases, experimental models are necessary. Cobalt, as part of the vitamin B12 complex, is important for neuronal integrity. However, it is known that high quantities of cobalt induce cytotoxic mechanisms via hypoxia mimicry. Therefore, we tested the degenerative effect of cobalt chloride (CoCl₂) on neurons and microglia in a porcine retina organ culture model. Organotypic cultures of porcine retinas were cultured and treated with different concentrations of CoCl₂ (0, 100, 300 and 500 μM) for 48 h. After four and eight days, CoCl₂ induced a strong degeneration of the porcine retina, starting at 300 μM. A loss of retinal ganglion cells (RGCs, Brn-3a), amacrine cells (calretinin) and bipolar cells (PKCα) was observed. Additionally, a high expression of hypoxia induced factor-1a (HIF-1a) and heat shock protein 70 (HSP70) was noted at both points in time. Also, the Caspase 3 protein was activated and P21 expression was induced. However, only at day four, the Bax/Bcl-2 ratio was increased. The effect of CoCl₂ was not restricted to neurons. CoCl₂ concentrations reduced the microglia amount (Iba1) and activity (Iba1 + Fc_γ-Receptor) at both points in time. These damaging effects on microglia were surprising, since CoCl₂ causes hypoxia and a pro-inflammatory environment. However, high concentrations of CoCl₂ also seem to be toxic to these cells. Similar degenerative mechanisms as in comparison to retinal ischemia animal models were observed. In summary, an effective and reproducible hypoxia-mimicking organotypic model for retinal degeneration was established, which is easy to handle and ready for drug studies.

Progressive versus Nonprogressive Intracranial Dural Arteriovenous Fistulas: Characteristics and Outcomes

BACKGROUND AND PURPOSE

A minority of intracranial dural arteriovenous fistulas progress with time. We sought to determine features that predict progression and define outcomes of patients with progressive dural arteriovenous fistulas.

MATERIALS AND METHODS

We performed a retrospective imaging and clinical record review of patients with intracranial dural arteriovenous fistula evaluated at our hospital.

RESULTS

Of 579 patients with intracranial dural arteriovenous fistulas, 545 had 1 fistula (mean age, 45 ± 23 years) and 34 (5.9%) had enlarging, de novo, multiple, or recurrent fistulas (mean age, 53 ± 20 years; P = .11). Among these 34 patients, 19 had progressive dural arteriovenous fistulas with de novo fistulas or fistula enlargement with time (mean age, 36 ± 25 years; progressive group) and 15 had multiple or recurrent but nonprogressive fistulas (mean age, 57 ± 13 years; P = .0059, nonprogressive group). Whereas all 6 children had fistula progression, only 13/28 adults (P = .020) progressed. Angioarchitectural correlates to chronically elevated intracranial venous pressures, including venous sinus dilation (41% versus 7%, P = .045) and pseudophlebitic cortical venous pattern (P = .048), were more common in patients with progressive disease than in those without progression. Patients with progressive disease received more treatments than those without progression (median, 5 versus 3; P = .0068), but as a group, they did not demonstrate worse clinical outcomes (median mRS, 1 and 1; P = .39). However, 3 young patients died from intracranial venous hypertension and intracranial hemorrhage related to progression of their fistulas despite extensive endovascular, surgical, and radiosurgical treatments.

CONCLUSIONS

Few patients with dural arteriovenous fistulas follow an aggressive, progressive clinical course despite treatment. Younger age at initial presentation and angioarchitectural correlates to venous hypertension may help identify these patients prospectively.

A quantum cascade laser-based water vapor isotope analyzer for environmental monitoring

A field-deployable mid-infrared quantum cascade laser-based spectrometer was designed and developed for measurements of H2(16)O and H2(18)O at 7.12 μm. H2(16)O and H2(18)O absorption features at 1390.52 cm(-1) and 1389.91 cm(-1), respectively, accessible within current tuning range of the laser, were targeted. The target lines were carefully selected to assure similar absorption levels and similar temperature sensitivities of the line strength due to comparable lower state energies. A real-time spectral fitting algorithm was implemented for isotopic concentration retrieval. Detection limits for H2(16)O and H2(18)O of 2.2 ppm and 7.0 ppb, respectively, were achieved at a dew point of 14 °C (volume mixing ratio of 15,766 ppm) in 1 s integration time, which resulted in a δ(18)O isotopic ratio measurement precision of 0.25‰. The ultimate minimum detection limits obtained after 160 s integration time for H2(16)O and H2(18)O, and δ(18)O measurements were 0.6 ppm, 1.7 ppb, and 0.05‰, respectively.