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Dive into the research topics where Alexander Chen is active.

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Featured researches published by Alexander Chen.


Cancer Cytopathology | 2013

Improved laboratory resource utilization and patient care with the use of rapid on‐site evaluation for endobronchial ultrasound fine‐needle aspiration biopsy

Brian T. Collins; Alexander Chen; Jeff F. Wang; Cory T. Bernadt; Souzan Sanati

Endobronchial ultrasound guided (EBUS) fine‐needle aspiration (FNA) biopsy has become widely used to evaluate patients with thoracic abnormalities. Rapid on‐site evaluation (ROSE) can provide the bronchoscopist with immediate evaluation findings during the procedure. This study examines EBUS FNA biopsy procedures with and without ROSE, and investigates the impact of ROSE service on the EBUS procedure and laboratory resource utilization.


European Respiratory Journal | 2015

A randomised trial of lung sealant versus medical therapy for advanced emphysema

Carolyn E. Come; Mordechai R. Kramer; Mark T. Dransfield; Muhanned Abu-Hijleh; David Berkowitz; Michela Bezzi; Surya P. Bhatt; Michael Boyd; Enrique Cases; Alexander Chen; Christopher B. Cooper; Javier Flandes; Thomas R. Gildea; Mark Gotfried; D. Kyle Hogarth; Kumaran Kolandaivelu; William Leeds; Timothy Liesching; Nathaniel Marchetti; Charles Hugo Marquette; Richard A. Mularski; Victor Pinto-Plata; Michael Pritchett; Samaan Rafeq; Edmundo Rubio; Dirk-Jan Slebos; Grigoris Stratakos; Alexander Sy; Larry W. Tsai; Momen M. Wahidi

Uncontrolled pilot studies demonstrated promising results of endoscopic lung volume reduction using emphysematous lung sealant (ELS) in patients with advanced, upper lobe predominant emphysema. We aimed to evaluate the safety and efficacy of ELS in a randomised controlled setting. Patients were randomised to ELS plus medical treatment or medical treatment alone. Despite early termination for business reasons and inability to assess the primary 12-month end-point, 95 out of 300 patients were successfully randomised, providing sufficient data for 3- and 6-month analysis. 57 patients (34 treatment and 23 control) had efficacy results at 3 months; 34 (21 treatment and 13 control) at 6 months. In the treatment group, 3-month lung function, dyspnoea, and quality of life improved significantly from baseline when compared to control. Improvements persisted at 6 months with >50% of treated patients experiencing clinically important improvements, including some whose lung function improved by >100%. 44% of treated patients experienced adverse events requiring hospitalisation (2.5-fold more than control, p=0.01), with two deaths in the treated cohort. Treatment responders tended to be those experiencing respiratory adverse events. Despite early termination, results show that minimally invasive ELS may be efficacious, yet significant risks (probably inflammatory) limit its current utility. Emphysematous lung sealant therapy is highly efficacious in some patients, but benefits bring significant risks http://ow.ly/JJ2vg


Annals of the American Thoracic Society | 2014

Radial Probe Endobronchial Ultrasound for Peripheral Pulmonary Lesions. A 5-Year Institutional Experience

Alexander Chen; Praveen Chenna; Andrea Loiselle; Jennifer Massoni; Martin L. Mayse; David Misselhorn

RATIONALE Technological advances have improved the ability of bronchoscopists to access peripheral pulmonary lesions for tissue sampling. Radial probe endobronchial ultrasound (EBUS) provides real-time feedback to guide biopsies of peripheral lesions, thereby potentially improving diagnostic yield over conventional bronchoscopy. OBJECTIVES We assessed the overall diagnostic yield of peripheral bronchoscopy using radial probe EBUS for peripheral pulmonary lesions, as well as factors that might influence the diagnostic yield, such as radial ultrasound view, lesion size, and ability to locate the peripheral lesion. METHODS We conducted a retrospective review of peripheral bronchoscopy cases in which radial probe EBUS was utilized to diagnose peripheral pulmonary lesions at a tertiary care university hospital. MEASUREMENTS AND MAIN RESULTS Our study cohort comprised 496 patients who underwent bronchoscopies between January 2008 and December 2012 for the diagnosis of peripheral pulmonary lesions. Radial probe EBUS was used alone for diagnostic purposes in 467 patients. A diagnosis was made on that basis in 321 (69%) of 467 patients. A diagnosis was obtained for 83 of 144 (58%) of nodules 1-2 cm in diameter, 99 of 137 (72%) of nodules 2.1-3 cm, 54 of 70 (77%) of nodules 3.1-4 cm, 41 of 47 (87%) of nodules 4.1-5 cm, and 35 of 40 (88%) of nodules larger than 5.1 cm. Of all 467 nodules, 446 (96%) were successfully identified using radial probe EBUS. When the radial probe position was within the target lesion, the diagnostic yield was 84% compared with 48% when the probe was positioned adjacent to the lesion. CONCLUSIONS Radial probe EBUS can be used to guide biopsy during peripheral bronchoscopy. This technique provides real-time ultrasound-based confirmation of target lesion localization prior to biopsy. Using radial probe EBUS, the vast majority of peripheral pulmonary nodules can be identified. Radial EBUS probe position relative to the target lesion significantly affects the diagnostic yield.


Chest | 2012

Latest Advances in Advanced Diagnostic and Therapeutic Pulmonary Procedures

Gerard A. Silvestri; David Feller-Kopman; Alexander Chen; Momen M. Wahidi; Kazuhiro Yasufuku; Armin Ernst

Over the past 15 years, patients with a myriad of pulmonary conditions have been diagnosed and treated with new technologies developed for the pulmonary community. Advanced diagnostic and therapeutic procedures once performed in an operating theater under general anesthesia are now routinely performed in a bronchoscopy suite under moderate sedation with clinically meaningful improvements in outcome. With the miniaturization of scopes and instruments, improvements in optics, and creative engineers, a host of new devices has become available for clinical testing and use. A growing community of pulmonologists is doing comparative effectiveness trials that test new technologies against the current standard of care. While more research is needed, it seems reasonable to provide an overview of pulmonary procedures that are in various stages of development, testing, and practice at this time. Five areas are covered: navigational bronchoscopy, endobronchial ultrasound, endoscopic lung volume reduction, bronchial thermoplasty, and pleural procedure. Appropriate training for clinicians who wish to provide these services will become an area of intense scrutiny as new skills will need to be acquired to ensure patient safety and a good clinical result.


Chest | 2015

The effect of respiratory motion on pulmonary nodule location during electromagnetic navigation bronchoscopy.

Alexander Chen; Nicholas J. Pastis; Brian Furukawa; Gerard A. Silvestri

BACKGROUND Electromagnetic navigation has improved the diagnostic yield of peripheral bronchoscopy for pulmonary nodules. For these procedures, a thin-slice chest CT scan is performed prior to bronchoscopy at full inspiration and is used to create virtual airway reconstructions that are used as a map during bronchoscopy. Movement of the lung occurs with respiratory variation during bronchoscopy, and the location of pulmonary nodules during procedures may differ significantly from their location on the initial planning full-inspiratory chest CT scan. This study was performed to quantify pulmonary nodule movement from full inspiration to end-exhalation during tidal volume breathing in patients undergoing electromagnetic navigation procedures. METHODS A retrospective review of electromagnetic navigation procedures was performed for which two preprocedure CT scans were performed prior to bronchoscopy. One CT scan was performed at full inspiration, and a second CT scan was performed at end-exhalation during tidal volume breathing. Pulmonary lesions were identified on both CT scans, and distances between positions were recorded. RESULTS Eighty-five pulmonary lesions were identified in 46 patients. Average motion of all pulmonary lesions was 17.6 mm. Pulmonary lesions located in the lower lobes moved significantly more than upper lobe nodules. Size and distance from the pleura did not significantly impact movement. CONCLUSIONS Significant movement of pulmonary lesions occurs between full inspiration and end-exhalation during tidal volume breathing. This movement from full inspiration on planning chest CT scan to tidal volume breathing during bronchoscopy may significantly affect the diagnostic yield of electromagnetic navigation bronchoscopy procedures.


The Annals of Thoracic Surgery | 2011

Endobronchial-Ultrasound Guided Miniforceps Biopsy of Mediastinal and Hilar Lesions

Ara Chrissian; David Misselhorn; Alexander Chen

BACKGROUND Linear array endobronchial ultrasound (EBUS) has greatly improved the diagnostic yield of transbronchial needle aspiration (TBNA) for the diagnosis of non-small cell lung carcinoma though its yield in granulomatous disease and lymphoproliferative disorders is less robust. The EBUS-miniforceps biopsy (MFB) uses miniforceps and the convex probe EBUS bronchoscope to obtain forceps biopsies of centrally located lesions under continuous ultrasound guidance. In this prospective study we evaluate the efficacy of this technique for diagnosing mediastinal and hilar abnormalities in patients with a low suspicion for non-small cell lung carcinoma. METHODS Patients presenting with mediastinal or hilar lymphadenopathy and a low likelihood of non-small cell lung carcinoma underwent EBUS-TBNA and EBUS-MFB of mediastinal and hilar abnormalities. The diagnostic yield EBUS-TBNA and EBUS-MFB was compared as was the combined yield of both techniques versus either technique alone. RESULTS Between June 2008 and July 2010, 50 patients underwent EBUS-TBNA and EBUS-MFB of 74 lymph node stations. The overall diagnostic yield of EBUS-TBNA and EBUS-MFB was 81% (60 of 74) and 91% (67 of 74), respectively (p=0.09). When the 2 techniques were combined, the overall diagnostic yield was 97% (72 of 74) (p<0.001), which was significant when compared with EBUS-TBNA alone. No complications were observed as a result of EBUS-MFB, and EBUS-MFB did not appear to significantly prolong the procedure. CONCLUSIONS The EBUS-miniforceps biopsy is an effective, safe, and efficient method of obtaining histopathologic specimens from mediastinal and hilar abnormalities in patients with a low likelihood of non-small cell lung carcinoma, particularly when the technique is combined with EBUS-TBNA.


Annals of the American Thoracic Society | 2016

Indwelling Tunneled Pleural Catheters for the Management of Hepatic Hydrothorax. A Pilot Study.

Alexander Chen; Jennifer Massoni; Diana Jung; Jeffrey S. Crippin

RATIONALE Hepatic hydrothorax is a complication of cirrhosis in which hydrostatic imbalances result in fluid accumulation within the pleural space. Although uncommon, this may cause significant morbidity, resulting in dyspnea requiring repeated pleural drainage procedures. Liver transplantation is curative, but it is rarely immediately available to qualified patients, presenting the clinical challenge of managing recurrent pleural effusions. Indwelling tunneled pleural catheters (ITPCs) have been used successfully to palliate dyspnea associated with recurrent malignant pleural effusions. OBJECTIVES This study was performed to evaluate the feasibility of using ITPCs for the management of hepatic hydrothorax. METHODS A single-center prospective feasibility study was performed to evaluate the use of ITPCs for the management of recurrent hepatic hydrothorax in patients who were eligible for liver transplant evaluation. MEASUREMENTS AND MAIN RESULTS Twenty-five ITPCs were placed in 24 patients. The mean number of pleural drainage procedures before ITPC placement was 1.9, with no further pleural drainages required in any patient after ITPC placement. Spontaneous pleurodesis occurred in 8 of 24 patients (33%). All eight catheters were successfully removed without pleural fluid reaccumulation. Mean time to pleurodesis was 131.8 days. Pleural fluid infection occurred in 4 of 24 patients (16.7%), requiring catheter removal in 3 of the 4 patients. CONCLUSIONS ITPCs may be successfully and safely used to control symptoms associated with hepatic hydrothorax. The rate of spontaneous pleurodesis that occurs is similar to that observed with ITPCs placed for malignant pleural effusion, although the infection rate may be higher. Clinical trial registered with www.clinicaltrials.gov (NCT02595567).


Pediatric Pulmonology | 2014

The use of convex probe endobronchial ultrasound-guided transbronchial needle aspiration in a pediatric population: A multicenter study

Christopher R. Gilbert; Alexander Chen; Jason Akulian; Hans J. Lee; Momen M. Wahidi; A. Christine Argento; Nichole T. Tanner; Nicholas J. Pastis; Kassem Harris; Daniel H. Sterman; Jennifer Toth; Praveen Chenna; David Feller-Kopman; Lonny Yarmus

The presence of intrathoracic lymphadenopathy and mediastinal masses in the pediatric population often presents a diagnostic challenge. With limited minimally invasive methodologies to obtain a diagnosis, invasive sampling via mediastinoscopy or thoracotomy is often pursued. Endobronchial ultrasound transbronchial needle aspiration (EBUS‐TBNA) is a minimally invasive, outpatient procedure that has demonstrated significant success in the adult population in the evaluation of such abnormalities. Within the pediatric literature there is limited data regarding the use of EBUS‐TBNA. We report the first multicenter review of a pediatric population undergoing EBUS‐TBNA procedures identifying the feasibility, safety, utility, and outcomes of this procedure.


Seminars in Respiratory and Critical Care Medicine | 2014

Radial Probe Endobronchial Ultrasound and Novel Navigation Biopsy Techniques

Praveen Chenna; Alexander Chen

Peripheral pulmonary lesions are an increasingly common finding in clinical practice. While many nodules are followed with radiographic surveillance, some may require biopsy. Conventional bronchoscopy with transbronchial lung biopsy has traditionally performed poorly for small, peripheral lesions, and transthoracic needle aspiration with computed tomographic (CT) guidance has been favored as the diagnostic test of choice. Despite the high diagnostic yield of transthoracic needle aspiration, procedural complications such as pneumothorax continue to be problematic. New technology has been developed to improve the diagnostic yield of bronchoscopy for peripheral lesions over conventional methods, while maintaining the favorable safety profile of a bronchoscopic approach. Virtual bronchoscopy and electromagnetic navigation are CT-based image guidance systems that create virtual bronchoscopic representations of the tracheobronchial tree to assist the bronchoscopist in locating peripheral lesions. Radial probe endobronchial ultrasound utilizes real-time ultrasound to confirm the location of peripheral lesions before biopsy. This article summarizes the technical platforms, procedures, and clinical evidence for these emerging technologies.


Journal of bronchology & interventional pulmonology | 2009

ECMO-assisted Rigid Bronchoscopy for Tracheal Obstruction.

Alexander Chen

Extracorporeal membrane oxygenation in adults is typically reserved for thoracic or cardiac procedures in which insult to the pulmonary circuit has occurred or is anticipated. In this brief report, I describe a case of tracheal obstruction resulting from a retained tracheal stent that was removed through rigid bronchoscopy with extracorporeal membrane oxygenation support.

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Nicholas J. Pastis

Medical University of South Carolina

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Gerard A. Silvestri

Medical University of South Carolina

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David Misselhorn

Washington University in St. Louis

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Lonny Yarmus

Johns Hopkins University

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Nichole T. Tanner

Medical University of South Carolina

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Jason Akulian

University of North Carolina at Chapel Hill

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Praveen Chenna

Washington University in St. Louis

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Hans J. Lee

Johns Hopkins University

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Andrea Loiselle

Washington University in St. Louis

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