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Shehata M, Shalaby A, Switala AE, El-Baz M, Ghazal M, Fraiwan L, Khalil A, El-Ghar MA, Badawy M, Bakr AM, Dwyer A, Elmaghraby A, Giridharan G, Keynton R, El-Baz A. A multimodal computer-aided diagnostic system for precise identification of renal allograft rejection: Preliminary results. Med Phys 2020; 47:2427-2440. [PMID: 32130734 DOI: 10.1002/mp.14109] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 02/18/2020] [Accepted: 02/18/2020] [Indexed: 12/26/2022] Open
Abstract
PURPOSE Early assessment of renal allograft function post-transplantation is crucial to minimize and control allograft rejection. Biopsy - the gold standard - is used only as a last resort due to its invasiveness, high cost, adverse events (e.g., bleeding, infection, etc.), and the time for reporting. To overcome these limitations, a renal computer-assisted diagnostic (Renal-CAD) system was developed to assess kidney transplant function. METHODS The developed Renal-CAD system integrates data collected from two image-based sources and two clinical-based sources to assess renal transplant function. The imaging sources were the apparent diffusion coefficients (ADCs) extracted from 47 diffusion-weighted magnetic resonance imaging (DW-MRI) scans at 11 different b-values (b0, b50, b100, ..., b1000 s/mm 2 ), and the transverse relaxation rate (R2*) extracted from 30 blood oxygen level-dependent MRI (BOLD-MRI) scans at 5 different echo times (TEs = 2, 7, 12, 17, and 22 ms). Serum creatinine (SCr) and creatinine clearance (CrCl) were the clinical sources for kidney function evaluation. The Renal-CAD system initially performed kidney segmentation using the level-set method, followed by estimation of the ADCs from DW-MRIs and the R2* from BOLD-MRIs. ADCs and R2* estimates from 30 subjects that have both types of scans were integrated with their associated SCr and CrCl. The integrated biomarkers were then used as our discriminatory features to train and test a deep learning-based classifier, namely stacked autoencoders (SAEs) to differentiate non-rejection (NR) from acute rejection (AR) renal transplants. RESULTS Using a leave-one-subject-out cross-validation approach along with SAEs, the Renal-CAD system demonstrated 93.3% accuracy, 90.0% sensitivity, and 95.0% specificity in differentiating AR from NR. Robustness of the Renal-CAD system was also confirmed by the area under the curve value of 0.92. Using a stratified tenfold cross-validation approach, the Renal-CAD system demonstrated its reproducibility and robustness by a diagnostic accuracy of 86.7%, sensitivity of 80.0%, specificity of 90.0%, and AUC of 0.88. CONCLUSION The obtained results demonstrate the feasibility and efficacy of accurate, noninvasive identification of AR at an early stage using the Renal-CAD system.
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Affiliation(s)
- Mohamed Shehata
- BioImaging Lab, Department of Bioengineering, University of Louisville, Louisville, KY, 40208, USA
| | - Ahmed Shalaby
- BioImaging Lab, Department of Bioengineering, University of Louisville, Louisville, KY, 40208, USA
| | - Andrew E Switala
- BioImaging Lab, Department of Bioengineering, University of Louisville, Louisville, KY, 40208, USA
| | - Maryam El-Baz
- BioImaging Lab, Department of Bioengineering, University of Louisville, Louisville, KY, 40208, USA
| | - Mohammed Ghazal
- Electrical and Computer Engineering Department, Abu Dhabi University, Abu Dhabi, 59911, UAE
| | - Luay Fraiwan
- Electrical and Computer Engineering Department, Abu Dhabi University, Abu Dhabi, 59911, UAE
| | - Ashraf Khalil
- Computer Science and Information Technology Department, Abu Dhabi University, Abu Dhabi, 59911, UAE
| | - Mohamed Abou El-Ghar
- Urology and Nephrology Center, Radiology Department, Mansoura University, Mansoura, 35516, Egypt
| | - Mohamed Badawy
- Urology and Nephrology Center, Radiology Department, Mansoura University, Mansoura, 35516, Egypt
| | - Ashraf M Bakr
- Pediatric Nephrology Unit, Mansoura University Children's Hospital, University of Mansoura, Mansoura, 35516, Egypt
| | - Amy Dwyer
- Kidney Disease Program, University of Louisville, Louisville, KY, 40202, USA
| | - Adel Elmaghraby
- Computer Engineering and Computer Science Department, University of Louisville, Louisville, KY, 40208, USA
| | | | - Robert Keynton
- Department of Bioengineering, University of Louisville, Louisville, KY, 40208, USA
| | - Ayman El-Baz
- Department of Bioengineering, University of Louisville, Louisville, KY, 40208, USA.,200 E Shipp Ave, Lutz 390 Hall, Room 419, Louisville, KY, 40208, USA
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Albert NM. Use of novel oral anticoagulants for patients with atrial fibrillation: systematic review and clinical implications. Heart Lung 2013; 43:48-59. [PMID: 24373340 DOI: 10.1016/j.hrtlng.2013.10.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 10/26/2013] [Accepted: 10/29/2013] [Indexed: 10/26/2022]
Abstract
Atrial fibrillation (AF), a common arrhythmia, increases the risk of ischemic stroke. Stroke and bleeding scores for patients with AF can help to stratify risk and determine the need for antithrombotic therapy, for which warfarin has been the gold standard. Although highly effective, warfarin has several limitations that can lead to its underuse. Data from randomized, Phase III clinical trials of the novel oral anticoagulants, dabigatran, a direct thrombin inhibitor, and rivaroxaban and apixaban, both factor Xa inhibitors, indicate these drugs are at least noninferior to warfarin for the prevention of stroke and systemic embolism. They are easier to administer, and have an equivalent or lower risk of bleeding versus warfarin. A better understanding of the risks and benefits of the novel oral anticoagulants, and their use in clinical practice, will prepare clinicians to anticipate and address educational and clinical needs of AF patients and their families, and promote evidence-based prescription of appropriate and safe anticoagulation therapy.
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Key Words
- AF
- Atrial fibrillation
- CHA(2)DS(2)-VASc
- CHADS(2)
- CI
- CrCl
- Dabigatran
- GI
- HAS-BLED
- ICH
- INR
- MI
- Novel oral anticoagulants
- RR
- Rivaroxaban
- TTR
- Warfarin
- atrial fibrillation
- cardiac failure, hypertension, age, diabetes, stroke (doubled)
- confidence interval
- congestive heart failure, hypertension, age ≥75 years (doubled), diabetes, previous stroke or transient ischemic attack (doubled), vascular disease, sex category
- creatinine clearance
- gastrointestinal
- hypertension, abnormal renal/liver function, stroke, bleeding history or predisposition, labile international normalized ratio, elderly, drugs/alcohol
- international normalized ratio
- intracranial hemorrhage
- myocardial infarction
- relative risk
- time in therapeutic range
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Affiliation(s)
- Nancy M Albert
- Research and Innovation, Cleveland Clinic Health System, USA; George M and Linda H Kaufman Center for Heart Failure, Heart and Vascular Institute, Cleveland Clinic, 9500 Euclid Avenue J3-4, Cleveland, OH 44195, USA.
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Reilly PA, Lehr T, Haertter S, Connolly SJ, Yusuf S, Eikelboom JW, Ezekowitz MD, Nehmiz G, Wang S, Wallentin L. The effect of dabigatran plasma concentrations and patient characteristics on the frequency of ischemic stroke and major bleeding in atrial fibrillation patients: the RE-LY Trial (Randomized Evaluation of Long-Term Anticoagulation Therapy). J Am Coll Cardiol 2013; 63:321-8. [PMID: 24076487 DOI: 10.1016/j.jacc.2013.07.104] [Citation(s) in RCA: 630] [Impact Index Per Article: 57.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 06/17/2013] [Accepted: 07/01/2013] [Indexed: 11/19/2022]
Abstract
OBJECTIVES The goal of this study was to analyze the impact of dabigatran plasma concentrations, patient demographics, and aspirin (ASA) use on frequencies of ischemic strokes/systemic emboli and major bleeds in atrial fibrillation patients. BACKGROUND The efficacy and safety of dabigatran etexilate were demonstrated in the RE-LY (Randomized Evaluation of Long-Term Anticoagulation Therapy) trial, but a therapeutic concentration range has not been defined. METHODS In a pre-specified analysis of RE-LY, plasma concentrations of dabigatran were determined in patients treated with dabigatran etexilate 110 mg twice daily (bid) or 150 mg bid and correlated with the clinical outcomes of ischemic stroke/systemic embolism and major bleeding using univariate and multivariate logistic regression and Cox regression models. Patient demographics and ASA use were assessed descriptively and as covariates. RESULTS Plasma concentrations were obtained from 9,183 patients, with 112 ischemic strokes/systemic emboli (1.3%) and 323 major bleeds (3.8%) recorded. Dabigatran levels were dependent on renal function, age, weight, and female sex, but not ethnicity, geographic region, ASA use, or clopidogrel use. A multiple logistic regression model (c-statistic 0.657, 95% confidence interval [CI]: 0.61 to 0.71) showed that the risk of ischemic events was inversely related to trough dabigatran concentrations (p = 0.045), with age and previous stroke (both p < 0.0001) as significant covariates. Multiple logistic regression (c-statistic 0.715, 95% CI: 0.69 to 0.74) showed major bleeding risk increased with dabigatran exposure (p < 0.0001), age (p < 0.0001), ASA use (p < 0.0003), and diabetes (p = 0.018) as significant covariates. CONCLUSIONS Ischemic stroke and bleeding outcomes were correlated with dabigatran plasma concentrations. Age was the most important covariate. Individual benefit-risk might be improved by tailoring dabigatran dose after considering selected patient characteristics. (Randomized Evaluation of Long Term Anticoagulant Therapy [RE-LY] With Dabigatran Etexilate; NCT00262600).
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Affiliation(s)
- Paul A Reilly
- Departments of Clinical Development and Clinical Biostatistics, Boehringer Ingelheim Pharmaceuticals, Ridgefield, Connecticut.
| | - Thorsten Lehr
- Departments of Translational Medicine and Biometry, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany; Saarland University, Saarbrücken, Germany
| | - Sebastian Haertter
- Departments of Translational Medicine and Biometry, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
| | - Stuart J Connolly
- Population Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Salim Yusuf
- Population Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - John W Eikelboom
- Population Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | | | - Gerhard Nehmiz
- Departments of Translational Medicine and Biometry, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
| | - Susan Wang
- Departments of Clinical Development and Clinical Biostatistics, Boehringer Ingelheim Pharmaceuticals, Ridgefield, Connecticut
| | - Lars Wallentin
- Uppsala Clinical Research Centre and Department of Medical Sciences, Uppsala University, Uppsala, Sweden
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