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CHEST publishes select peer-reviewed, accepted manuscripts Online First each week. The media embargo is lifted on the date of Online First publication. Final, edited versions will appear in a numbered issue of CHEST and may contain substantive changes. We encourage readers to check back for the final article. Online First papers are indexed in PubMed and by search engines, but the information, including the final title and author list, may be updated on final publication.

original research 
Daniel R. Murphy, MD MBA; Ashley N.D. Meyer, PhD; Viraj Bhise, MBBS; Elise Russo, MPH; Dean F. Sittig, PhD; Li Wei; Louis Wu, PA; Hardeep Singh, MD MPH
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Background  We tested a “trigger” algorithm to identify delays in follow-up of abnormal chest imaging results in a large national clinical data warehouse of electronic health record (EHR) data.

Methods  We applied a trigger in a repository hosting EHR data from all US Veterans Affairs (VA) healthcare facilities and analyzed data from seven facilities. Using literature reviews and expert input, we refined previously-developed trigger criteria designed to identify patients potentially experiencing delays in diagnostic evaluation of chest imaging flagged as ‘suspicious for malignancy.’ The trigger then excluded patients where further evaluation was unnecessary (e.g., those with terminal illnesses or already completed biopsies). We programmed the criteria into a computerized algorithm. Reviewers examined a random sample of trigger-positive (i.e., patients with trigger-identified delay) and trigger negative (i.e. patients with an abnormal imaging result, but no delay) records and confirmed presence or absence of delay or need for additional tracking (e.g., repeat imaging in 6-months). We calculated trigger positive and negative predictive values, sensitivity, and specificity.

Results  On application to 208,633 patients seen between 1/1/2012-12/31/2012, 40,218 chest imaging tests were performed, of which 1847 results were suspicious for malignancy and 655 (35%) were trigger-positive. Review of 400 randomly selected trigger-positive patients found 158 (40%) with confirmed delays and 84 (21%) requiring additional tracking (PPV=61%;95%CI:55.5%-65.3%). Review of 100 trigger-negative patients identified 97 without delay (NPV=97%;95%CI:90.8%-99.2%). Sensitivity and specificity were 99% (95%CI:96.2%-99.7%) and 38% (95%CI:32.1-44.3%), respectively.

Conclusions  Application of triggers on ‘big’ EHR data may aid in identifying patients experiencing delays in diagnostic evaluation of chest imaging results suspicious for malignancy.

translating basic research in clinical practice 
Stijn E. Verleden; Annelore Sacreas; Robin Vos; Bart M. Vanaudenaerde; Geert M. Verleden
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Bronchiolitis obliterans syndrome (BOS) remains a major complication after lung transplantation, causing significant morbidity and mortality in a majority of the recipients. BOS is believed to be the clinical correlate of chronic allograft dysfunction and is defined as an obstructive pulmonary function defect in the absence of other identifiable causes, mostly not amenable to treatment. Recently, it has become clear that BOS is not the only form of chronic allograft dysfunction and that other clinical phenotypes exist, however we will focus exclusively on BOS. Radiology typically demonstrates air trapping, mosaic attenuation and hyperinflation. Pathology reveals obliterative bronchiolitis lesions, a pure obliteration of the small airways (<2mm), with a relatively normal surrounding parenchyma. In this review, we will highlight recent advances in the diagnosis, pathology and risk factors like microbes, viruses and antibodies. Although the pathophysiological mechanisms remain largely unknown, we will review the role of the airway epithelium and inflammation and the various experimental animal models. We will also clarify clinical and therapeutical implications of these findings. Although significant progress has been made, the exact pathophysiological mechanisms and adequate therapy for post-transplant BOS remain unknown, highlighting the need for further research to improve long-term post-transplant BOS-free and overall survival.

original research 
Evaldo Marchi, MD; PhD; Marcus V.H. de Carvalho, MD, PhD; Tiago R. Ventureli, MD; Andre J. Fruchi, PT; Ariane Lazaro, MD; Deborah C. do Carmo, MD; Thayssa YAS. Barreto, MD; Bruno V.B. Dias, MD; Milena M.P. Acencio, BS; Lisete R. Teixeira, MD; Richard W. Light, MD
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Background  Pleurodesis performed either by pleurectomy or pleural abrasion is recommended in the approach of primary spontaneous pneumothorax (PSP) to avoid recurrence. However, the efficacy of parietal pleural abrasion in producing pleurodesis is questioned. This study aims to determine the efficacy of apical abrasion alone, abrasion plus fibrin sealant application and pleurectomy in producing pleurodesis in rabbits.

Methods  Rabbits were submitted to video assisted thoracic surgery (VATS) alone (control) or VATS with apical gauze abrasion, abrasion plus fibrin sealant instillation or apical pleurectomy. Blood samples were collected in times pre-operatively, after 48 hours and 28 days to measure total leukocytes (WBC), neutrophil counts and serum interleukin 8 (IL-8) levels. After 28 days the animals were sacrificed for macroscopic evaluation of the degree of apical pleurodesis and microscopic evaluation of local pleural fibrosis and collagen deposition.

Results  WBC and neutrophil counts were similar in all groups, whereas serum IL-8 peaked at 48 hours in all groups and decreased after 28 days, except in the pleurectomy group. After 28 days the abrasion plus fibrin sealant and pleurectomy groups had significantly higher pleural adhesions, pleural fibrosis and collagen deposition than the abrasion alone group, mainly due to thick mature fibers.

Conclusions  Abrasion with local fibrin sealant instillation is as effective as pleurectomy in producing pleurodesis in rabbits. Apical pleurectomy elicits a more persistent elevation of serum IL-8 levels than apical abrasion alone or abrasion plus fibrin adhesive instillation.

original research 
Janet B. Croft, PhD; Hua Lu, MS; Xingyou Zhang, PhD; James B. Holt, PhD

Background  Geographic clusters in prevalence and hospitalizations for chronic obstructive pulmonary disease (COPD) have been identified at national, state, and county levels. The study objective is to identify county-level geographic accessibility to pulmonologists for adults with COPD.

Methods  Service locations of 12,392 practicing pulmonologists and 248,160 primary care physicians were identified from the 2013 National Provider Identifier Registry and weighted by census block-level populations within a series of circular distance buffer zones. Model-based county-level population counts of US adults aged >18 years with COPD were estimated from the 2013 Behavioral Risk Factor Surveillance System. The percentages of all estimated adults with potential access to at least one provider type and the county-level ratio of adults with COPD per pulmonologist were estimated for selected distances.

Results  The majority of US adults (100% in urbanized areas, 99.5% in urban clusters, and 91.7% in rural areas) had geographic access to a primary care physician within a 10-mile buffer distance; almost all (>99.9%) had access to a primary care physician within 50 miles. At least one pulmonologist within 10 miles was available for 97.5% of US adults living in urbanized areas, but only for 38.3% in urban clusters and 34.5% in rural areas. When distance increased to 50 miles, at least one pulmonologist was available for 100% in urbanized areas, 93.2% in urban clusters, and 95.2% in rural areas. County-level ratios of adults with COPD per pulmonologist varied greatly across the US with residents in many counties in the Midwest having no pulmonologist within 50 miles.

Conclusions  County-level geographic variations in pulmonologist access for adults with COPD suggest that those adults with limited access will have to depend upon care from primary care physicians.

special features 
Suhail Raoof, MD; Praveen Bondalapati, MD; Ravikanth Vydyula, MD; Jay Ryu, MD; Nishant Gupta, MD; Sabiha Raoof, MD; Jeff Galvin, MD; Mark J. Rosen, MD; David Lynch, MD; William Travis, MD; Sanjeev Mehta, MD; Richard Lazzaro, MD; David Naidich, MD
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Cysts are commonly seen on CT scans of the lungs, and diagnosis may be challenging. Clinical and radiographic features combined with a multidisciplinary approach may help differentiate among various disease entities, allowing correct diagnosis. It is important to distinguish cysts from cavities as they each have distinct etiologies and associated clinical disorders. Conditions like emphysema, honeycomb lung and cystic bronchiectasis may also mimic cystic disease. A simplified classification of cysts is proposed. Cysts may be present in greater profusion in the sub-pleural areas, when they typically represent paraseptal emphysema or bullae. Cysts present in the lung parenchyma but away from sub-pleural areas may be classified as simple, i.e. without any other abnormalities on high resolution CT scans (HRCT). These are further categorized into solitary or multifocal/diffuse cysts. Multifocal cysts may be seen with lymphocytic interstitial pneumonia, Birt-Hogg-Dubé syndrome, tracheobronchial papillomatosis or primary and metastatic cancers. Multifocal cysts may be associated with nodules (lymphocytic interstitial pneumonia, light chain deposition disease, amyloidosis, and Langerhan’s cell histiocytosis) or with ground glass opacities (Pneumocystis jiroveci pneumonia and desquamative interstitial pneumonia). Using the results of the HRCT as a starting point, and incorporating the clinical history, physical examination and laboratory findings are likely to narrow the differential diagnosis of cystic lesions considerably.

commentary 
Renli Qiao, MD, PhD, FCCP; Darcy Marciniuk, MD, FRCPC, FCCP; Nicki Augustyn; Mark J. Rosen, MD, Master FCCP; Huaping Dai, MD; Rongchang Chen, MD, FCCP, FCCP; Sinan Wu, MD; Chen Wang, MD, PhD, FCCP
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This article provides an update on progress toward establishing pulmonary and critical care medicine (PCCM) fellowship training as one of the first four subspecialties to be recognized and supported by the Chinese government. Designed and implemented throughout 2013-2014 by a collaborative effort of the Chinese Thoracic Society (CTS) and the American College of CHEST Physicians (CHEST), 12 leading Chinese hospitals enrolled a total of 64 fellows into standardized PCCM training programs with common curricula, educational activities and assessment measures. Supplemental educational materials, online assessment tools and institutional site visits designed to evaluate and provide feedback on the programs’ progress are being provided by CHEST. As a result of this initial progress, the Chinese government, through the Chinese Medical Doctor’s Association, endorsed the concept of subspecialty fellowship training in China, with PCCM as one of the four pilot subspecialties to be operationalized nationwide in 2016, followed by implementation across other subspecialties by 2020. This article also reflects on the achievements of the training sites and the challenges they face, and outlines plans to enhance and expand PCCM training and practice in China.

original research 
Viswam S. Nair, MD, MS; Vandana Sundaram, MPH; Michael K. Gould, MD, MS; Manisha Desai, PhD
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Background  Positron emission tomography (PET) is a diagnostic tool for lung cancer evaluation. No studies have ascertained practice patterns and determined the appropriateness of PET use in a large group of U.S. patients with screen detected lung nodules.

Methods  We analyzed participants in the National Lung Screening Trial (NLST) with positive screening test results and identified individuals with a PET scan performed prior to lung cancer diagnosis (diagnostic PET). Appropriate scan was defined as one performed in a patient with a nodule ≥ 0.8 cm. Logistic regression was used to assess factors associated with diagnostic PET use and appropriateness of PET use.

Results  Diagnostic PET was performed in 1,556 of 14,195 (11%) patients with positive screens; 331 of these (21%) were inappropriate. PET use by endemic fungal disease area was comparable although patients from the Northeast/Southeast were twice as likely as the West to have a diagnostic PET. Trial arm, older age, gender, nodule size ≥ 0.8 cm, upper lobe location, and spiculated margin were variables positively associated with use. Trial arm, older age and spiculated margin were positively associated with appropriate use. Only 561 (36%) diagnostic PETs were recommended by a radiologist and 284 (86%) PETs performed for nodules < 0.8 cm were ordered despite no recommendation from a radiologist.

Conclusions  PET was differentially utilized in the NLST and inappropriately used in many cases against radiologist recommendations. These data suggest PET may be over utilized in the lung cancer screening population and may contribute to excess healthcare costs.

original research 
Rishi Sharma; Olurinde A. Oni; Guoqing Chen; Mukut Sharma; Buddhadeb Dawn; Ram Sharma; Deepak Parashara; Virginia J. Savin; Rajat S. Barua; Kamal Gupta
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Background  Testosterone Replacement Therapy (TRT) prescriptions have increased several-fold in the last decade. There have been concerns regarding a possible increased incidence of deep venous thrombosis (DVT) and pulmonary embolism (PE) with TRT. There is a paucity of data to support the association between TRT and DVT/ PE. We evaluated the incidence of DVT and PE in men who were prescribed TRT for low serum total testosterone levels (sTT).

Methods  This is a retrospective cohort study, conducted using data obtained from the Veterans Administrations Informatics and Computing Infrastructure (VINCI). We compared the incidence of DVT/PE between those who received TRT and subsequently had normal on-treatment sTT levels (Gp1), those who received TRT but continued to have low on-treatment sTT (Gp2), and those who did not receive TRT (Gp3). Those with prior history of DVT/PE, cancer, hypercoagulable state and chronic anticoagulation were excluded.

Results  The final cohort consisted of 71,407 subjects with low baseline sTT. Of these, 10,854 did not receive TRT (Gp3) and 60,553 received TRT. Of those who received TRT, 38362 achieved normal sTT (Gp1) while 22191 continued to have low sTT (Gp2). The incidence of DVT/PE was 0.5%, 0.4% and 0.4% in Gp1, Gp2 and Gp3 respectively. Univariate, Multivariate, and Stabilized inverse probability of treatment weights (SIPTW) analyses showed no statistically significant difference in DVT/PE free survival between different groups.

Conclusion  This study did not detect a significant association between testosterone replacement therapy and risk of DVT/PE in adult men with low sTT who were at low-moderate baseline risk of DVT/PE.

topics in practice management 
Thomas R. Gildea, MD MS FACP FCCP; Katina Nicolacakis, MD FCCP
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Endobronchial Ultrasound (EBUS) has become an invaluable tool in the diagnosis of patients with a variety of thoracic abnormalities. The majority of EBUS procedures are used to diagnose and stage mediastinal and hilar abnormalities as well as peripheral pulmonary targets with a probe based technology. Nearly 1000 articles have been written about its use and utility. New Current Procedural Terminology (CPT®) codes have been introduced in 2016 to better capture the work and clinical use associated with the various types of EBUS procedures. The existing 31620 code has been deleted and replaced by three new codes, 31652, 31653 and 31654. These new codes have been through the valuation process and the new rule for reimbursement has been active since January 1st 2016 and with National Correct Coding Initiative (NCCI) correction as of April 1, 2016. The impact of these new codes will result in a net reduction in professional and technical reimbursement. This article describes the current use of EBUS and explains the current codes and professional reimbursement.

topics in practice management 
Jason S. Fritz, MD; K. Akaya Smith, MD
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Pulmonary hypertension is an increasingly recognized cause of morbidity and mortality and in the last 20 years there has been a rapid expansion in research and available therapies. Although it is defined quite simply as a mean pulmonary arterial pressure of 25 mm or greater, PH encompasses a heterogeneous group of disease processes. In the past, PH was classified as primary or secondary, but as understanding of the various contributing diseases has increased, classification systems have attempted to group these diseases by clinical features and disease mechanism. The evaluation of patients with suspected PH can be cumbersome but a careful and methodical approach is needed to ensure timely and accurate diagnosis, correct physiologic classification, and appropriate treatment. In this review, we will discuss the classification and diagnostic evaluation of PH in adults as well as some of the billing and coding considerations involved in this evaluation.

original research 
Jessica A. Beatty, MSc; Sumit R. Majumdar, MD; Gregory J. Tyrrell, PhD; Thomas J. Marrie, MD; Dean T. Eurich, PhD
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Background  Previous studies suggest smoking is independently associated with decreased mortality in patients with pneumonia. We hypothesized this is a result of acquiring differential pneumococcal serotypes (i.e., that smokers with [pneumococcal] pneumonia are more likely to become bacteremic with low case fatality rate (CFR) serotypes) and tested this hypothesis in a population-based cohort of patients with bacteremic pneumococcal pneumonia (BPP).

Methods  Our prospective population-based clinical registry included 1636 adults (≥18 years) with BPP hospitalized between 2000-2010 in Northern Alberta, Canada. Using multivariable logistic regression, we determined the adjusted risk of all-cause in-hospital mortality according to smoking status [current vs not] and conducted stratified analyses by serotypes [low CFR vs all other CFR] according to smoking status.

Results  Average age was 54 years, 57% were male, 49% were current smokers, and 41% had low CFR serotypes. Overall, 62 of 809 current smokers died in-hospital vs 164 of 827 non-smokers (8% vs 20%, adjusted odds ratio [aOR], 0.52; 95%CI, 0.36-0.77; P = 0.001). Current smokers were more likely to have low CFR serotype isolates than non-smokers (53% vs 29%, aOR, 1.67; 95%CI, 1.31-2.12; P < 0.001) and in models adjusted for low CFR serotype smoking remained independently associated with reduced mortality (P = 0.001).

Conclusion  Compared with non-smokers, current smokers with BPP had a decreased risk of in-hospital mortality and were more likely to be bacteremic with low CFR serotypes. These findings, at least partially, may explain why previous studies showed that smoking was associated with lower mortality in patients with pneumonia.

original research 
Mei Jiang, Ph.D; Wei-jie Guan, Ph.D; Zhang-fu Fang, Ph.D; Yan-qing Xie, Ph.D; Jia-xing Xie, Ph.D; Hao Chen, M.D; Dang Wei, M.D; Ke-fang Lai, M.D; Nan-shan Zhong, M.D
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Background  Clinical practice guidelines (CPGs) have been developed to provide healthcare practitioners with the best possible evidence, but their quality varies greatly.

Objective  To systematically evaluate the quality of cough CPGs and identify gaps limiting evidence-based practice.

Methods  Systematic searches were conducted to identify cough CPGs in guideline databases, developers’ websites and MEDLINE. Four reviewers independently evaluated eligible guidelines using Appraisal of Guidelines for Research and Evaluation II (AGREE II). Agreement among reviewers was assessed by intra-class correlation coefficient. The number of recommendations, strength of recommendation, and levels of evidence were determined.

Results  Fifteen cough CPGs were identified. An overall high-degree agreement among reviewers was observed (intra-class correlation coefficient: 0.82; 95% confidence interval: 0.79-0.85). The quality ranged from good to acceptable in scope and purpose (mean: 72%, range: 54-93%) and clarity and presentation domains (mean: 68%, range: 50-90%), but not in stakeholder involvement (mean: 36%, range: 18-90%), rigour of development (mean: 36%, range: 9-93%), applicability (mean: 23%, range: 9-83%) and editorial independence domains (mean: 24%, range: 0-96%). Seven guidelines (46.7%) were considered ‘strongly recommended’ or ‘recommended with modifications’ for clinical practice. More than 70% of recommendations were based on non-randomized studies (level C, 30.4%) and expert opinion (level D, 41.3%).

Conclusions  The quality of cough CPGs is variable and recommendations are largely based on low-quality evidence. There is a significant room for improvement to develop high-quality guidelines, which urgently warrants high-quality researches to minimize the vital gaps in the evidence for formulation of cough CPGs.

contemporary reviews in sleep medicine 
Miguel Ángel Martínez-García, MA. MD, PhD; Francisco Campos-Rodriguez, MD, PhD F; Ferrán Barbé, MD, PhD
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Despite the undeniable medical advances achieved in recent decades, cancer remains one of the main causes of mortality. Consequently, it is still extremely important to make every effort to discover new risk factors for this disease – particularly ones that can be treated or modified. Various pathophysiological pathways have been postulated as possible causes of cancer or its increased aggressiveness, and also of greater resistance to anti-tumoral treatment in the presence of both intermittent hypoxia and sleep fragmentation (both inherent to sleep apnea). So far, these biological hypotheses have been supported by various experimental studies on animals. Meanwhile, recent human studies drawing on pre-existing databases have observed an increase in cancer incidence and mortality in patients with a greater severity of sleep-disordered breathing. However, the methodological limitations of these studies (which are mostly retrospective and lack any measurement of direct markers of intermittent hypoxia or sleep fragmentation) point to a need for new controlled, prospective studies that would provide stronger scientific evidence on the existence of this association and its main characteristics, as well as exploring its nature and origin in greater depth. The great epidemiological impact of both cancer and sleep apnea and the potential for clinical treatment make this field of research an exciting challenge.

recent advances in chest medicine 
Tina Shah, MD, MPH; Valerie G. Press, MD, MPH; Megan Huisingh-Scheetz, MD, MPH; Steven R. White, MD
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Of patients hospitalized for an exacerbation of chronic obstructive pulmonary disease (COPD), one in five will require re-hospitalization within 30 days. Many developed countries are now implementing policies to increase care quality while controlling costs for COPD, known as value-based healthcare. In the US, COPD is part of Medicare’s Hospital Readmission Reduction Program (HRRP), penalizing hospitals for excess 30-day, all-cause readmissions after a hospitalization for an acute exacerbation of COPD, despite minimal evidence to guide hospitals on how to reduce readmissions. This review outlines challenges for improving overall COPD care quality and specifically for the HRRP. These challenges include heterogeneity in the literature for how COPD and readmissions are defined, difficulty finding the target population during hospitalizations, and a lack of literature to guide evidence-based programs for COPD readmissions as defined by the HRRP in the hospital setting. This review then identifies risk factors for early readmissions after acute exacerbation of COPD (AECOPD), and discusses tested and emerging strategies to reduce these readmissions. Finally, we evaluate the current HRRP and future policy changes and their effect on the goal to deliver value-based COPD care. COPD remains a chronic disease with a high prevalence that has finally garnered the attention of health systems and policymakers, but we still have a long way to go to truly deliver value-based care to our patients.

original research 
Won-Jung Koh, MD; Byeong-Ho Jeong, MD; Kyeongman Jeon, MD; Su-Young Kim, PhD; Kyoung Un Park, MD; Hye Yun Park, MD; Hee Jae Huh, MD; Chang-Seok Ki, MD; Nam Yong Lee, MD; Seung-Heon Lee, PhD; Chang Ki Kim, MD; Charles L. Daley, MD; Sung Jae Shin, PhD; Hojoong Kim, MD; O Jung Kwon, MD
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Background  Although Mycobacterium massiliense lung disease is increasing in patients with cystic fibrosis and non-cystic fibrosis bronchiectasis, optimal treatment regimens remain largely unknown. This study aimed to evaluate the efficacy of oral macrolide therapy after an initial two-week course of combination antibiotics for treating of M. massiliense lung disease.

Methods  Seventy-one patients received oral macrolides, along with an initial four-week (n = 28) or two-week (n = 43) intravenous (IV) amikacin and cefoxitin (or imipenem) treatment. These patients were treated for 24 months (4-week IV group) or for at least 12 months after negative sputum culture conversion (2-week IV group).

Results  Total treatment duration was longer in the 4-week IV group (median 23.9 months) than in the 2-week IV group (15.2 months, P < .001). The response rates after 12 months of treatment were 89% for symptoms, 79% for computed tomography, and 100% for negative sputum cultures in the 4-week IV group. In the 2-week IV group, these values were 100% (P = .057), 91% (P = .177), and 91% (P = .147) respectively. Acquired macrolide resistance developed in two patients in the 2-week IV group. Genotyping analyses of isolates from patients who failed to convert sputum culture to negative during treatment and from those who has positive culture after successful treatment completion revealed that most episodes were due to reinfection with different genotypes of M. massiliense.

Conclusions  Oral macrolide therapy after an initial two-week course of combination antibiotics might be effective in most patients with M. massiliense lung disease.

original research 
Flávia B. Nerbass, PT, PhD; Vera M.C. Salemi, MD, PhD; Rodrigo P. Pedrosa, MD, PhD; Natanael de P. Portilho, MD; Julio C.A. Ferreira-Filho, MD, PhD; Henrique T. Moriya, PhD; Murillo O. Antunes, MD; Edmundo Arteaga-Fernández, MD, PhD; Luciano F. Drager, MD, PhD; Geraldo Lorenzi-Filho, MD, PhD
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Background  Hypertrophic cardiomyopathy (HCM) is a common genetic disease that may cause left ventricular outflow tract (LVOT) obstruction, heart failure, and sudden death. Recent studies have shown a high prevalence of obstructive sleep apnea among patients with HCM. Because the hemodynamics of patients with LVOT obstruction are unstable and depend on load conditions to the heart, we evaluated the acute effects of CPAP on hemodynamics and cardiac performance in patients with HCM.

Methods  We studied 26 stable patients with HCM divided into nonobstructive-HCM (n=12) and obstructive-HCM (n=14) groups (LVOT gradient pressure lower or higher than 30 mm Hg, respectively). Patients in the supine position while awake were continuously monitored by beat-to-beat blood pressure and electrocardiography. A 2-dimensional echocardiography was performed at rest (Baseline) and after 20 minutes of nasal CPAP at 1.5 cmH2O and 10 cmH2O, which was applied in a random order interposed by 10 minutes without CPAP.

Results  Blood pressure, cardiac output, stroke volume, heart rate, left ventricular ejection fraction and LVOT gradient did not change during the study period in either group. CPAP at 10 cmH2O decreased right atrial size and right ventricular relaxation in all patients. CPAP at 10 cmH2O decreased left atrial volume significantly and decreased right ventricular outflow acceleration time, suggesting an increase in pulmonary artery pressure in obstructive patients.

Conclusions  The acute application of CPAP is apparently safe in patients with HCM. However, obstructive-HCM patients should be carefully monitored when initiated on CPAP due to its potential effects on pulmonary pressure.

original research 
Francesco Corradi, MD PhD; Claudia Brusasco, MD PhD; Antonella Vezzani, MD; Gregorio Santori, MD PhD; Tullio Manca, MD; Lorenzo Ball, MD; Francesco Nicolini, MD; Tiziano Gherli, MD; Vito Brusasco, MD
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Introduction  Lung ultrasonography (LUS) has been used for non-invasive detection of pulmonary edema. Semi-quantitative LUS visual scores (V-LUS) based on B-lines are moderately correlated with pulmonary capillary wedge pressure (PCWP) and extravascular lung water (EVLW). A new quantitative computer-aided LUS analysis (Q-LUS) has been recently proposed.

Aims  This study investigated 1) whether Q-LUS better correlates with PCWP and EVLW than V-LUS; 2) to which extent positive end-expiratory pressure (PEEP) affect the assessment of pulmonary edema by Q-LUS or V-LUS.

Methods  48 mechanically ventilated patients with PEEP of 5 or 10 cmH2O and monitored by PCWP (n=28) or EVLW (n=20) were studied.

Results  PCWP was significantly and strongly correlated with Q-LUS Grey Unit value (r2=0.70) but weakly with V-LUS B-line score (r2=0.20). EVLW was significantly and more strongly correlated with Q-LUS Grey Unit mean value (r2=0.68) than with V-LUS B-line score (r2=0.34). Q-LUS showed a better diagnostic accuracy than V-LUS for the detection of PCWP>18 mmHg or EVLW≥10 mL/kg. With 5-cmH2O PEEP, the correlations with PCWP or EVLW were stronger for Q-LUS than V-LUS. With 10-cmH2O PEEP, the correlations with PCWP or EVLW were still significant for Q-LUS but insignificant for V-LUS. Inter-observer reproducibility was better for Q-LUS than V-LUS.

Conclusions  Both V-LUS and Q-LUS are acceptable indicators of pulmonary edema in mechanically ventilated patients. However, at high PEEP only Q-LUS provides data that are significantly correlated with PCWP and EVLW. Computer-aided Q-LUS has the advantages of being not only independent of operator perception but also of PEEP.

original research 
Thomas A. Schwann, MD, MBA; Robert H. Habib, PhD; Rakesh M. Suri, MD; J. Matthew Brennan, MD; Xia He, MA; Vinod H. Thourani, MD; Milo Engoren, MD; Gorav Ailawadi, MD; Brian R. Englum, MD; Mark R. Bonnell, MD; James S. Gammie, MD
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Background  Anticoagulation with warfarin following bioprosthetic mitral valve replacement (BMVR) is recommended by multiple practice guidelines. We assessed practice variability and patient characteristics associated with warfarin prescription following BMVR.

Methods  7,637 patients in the Society of Thoracic Surgeons Database (1/1/2008-6/30/2011) who were discharged following isolated, primary, non-emergent BMVR were analyzed. Patients requiring pre-op warfarin, those with pre-op atrial fibrillation or contra-indication to warfarin were excluded. The association between patient, hospital, and surgeon characteristics and warfarin prescription were evaluated.

Results  58.0% of this cohort (median age, 66; female, 58.7%), was prescribed warfarin. Warfarin patients were older (67vs65yrs, p<0.0001), were less likely to have pre-operative: stroke (9.3%vs12.1%, p<0.001), CHF (51.4%vs54.1%, p<0.02) or dialysis (4.9%vs9.0%, p<0.001) and had a longer post-operative length of stay (8.0vs7.0 days, p<0.01). Warfarin was prescribed less often for patients with post-operative gastrointestinal events (44.4%vs55.6%, p< 0.001) but more often for patients with a post-operative myocardial infarction (75.8%vs24.2%, p<0.001), new atrial fibrillation (68.0%vs32.0%, p<0.001) and those requiring blood transfusions (intra-op (55.7%vs44.3%, p<0.001), post-op (57.0%vs43.0%, p<0.03). Similar rates of warfarin prescription were observed in patients requiring reoperation for bleeding (54.9%vs45.1%, p=0.20) and those with a post-operative stroke (53.6 %vs46.4 %, p=0.30). After adjusting for patient characteristics, significant surgeon and hospital variation in warfarin prescription at hospital was observed.

Conclusions  Although patient characteristics and post-operative events may be associated with the prescription of warfarin following BMVR, substantial surgeon and hospital variability remains. This variability largely ignores the established practice guidelines, and warrants further study to define the optimal anticoagulation strategy in BMVR patients.

contemporary reviews in sleep medicine 
Anita Valanju Shelgikar, MD, FAASM; P.F. Anderson, MILS; Marc R. Stephens, MAED
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Consumer-driven sleep tracking technologies are becoming increasingly popular with sleep disorders patients and the general population. As the list of sleep tracking technologies continues to grow, clinicians and researchers are faced with new challenges and opportunities to incorporate these technologies into current practice. We review diagnostic tools used in sleep medicine clinical practice, discuss categories of consumer sleep tracking technologies currently available, and explore advantages and disadvantages of each. Potential uses of consumer sleep tracking technologies to enhance sleep medicine patient care and research are also discussed.

original research 
R.G.S. Andrade; F. Madeiro; V.S. Piccin; H.T. Moriya; F. Schorr; P.S. Sardinha; G.M. Gregório; P.R. Genta; G. Lorenzi-Filho
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Introduction  CPAP is the gold standard treatment for obstructive sleep apnea (OSA) and was conceived to be applied through a nasal interface. This study was designed to determine the acute effects of changing the nasal CPAP route to oronasal and oral in upper airway patency during sleep in patients with OSA. We hypothesized that the oronasal route may compromise CPAP effectiveness to treat OSA

Methods  Eighteen patients (age: 44±9 years, body mass index: 33.8±4.7 Kg/m2, apnea-hypopnea: 49.0 ± 39.1 events/hour) slept with a customized oronasal mask with an nasal and oral sealed compartments connected to a multidirectional valve. Sleep was monitored by full polysomnography and induced by low doses of midazolam. Nasal CPAP was titrated up to holding pressure. Flow route was acutely changed to oronasal (n = 18) and oral route (n = 16) during sleep. Retroglossal area was continuously observed by nasoendoscopy.

Results  Nasal CPAP (14.8±4.1 cmH2O) was able to stabilize breathing in all patients. In contrast, CPAP delivered by the oronasal and oral route promoted obstructive events in 12 (66.7%) and 14 (87.5%) patients, respectively. Compared to stable breathing during the nasal route, there was a significant and progressive reduction in the distance between the epiglottis and tongue base and the retroglossal area when CPAP was delivered by oronasal and oral route, respectively

Conclusions  CPAP delivered through the oronasal route may compromise CPAP effectiveness to treat OSA.

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  • CHEST Journal
    Print ISSN: 0012-3692
    Online ISSN: 1931-3543