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Khabbaz, Kamal

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Khabbaz

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Kamal

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Khabbaz, Kamal

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2013 - 20177

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Author's Publications: search.filters.isAuthorOfPublication.4f3fffb0-a5ae-4008-af58-0c71aa15f9cb

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Now showing 1 - 7 of 7
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    Customized Prediction of Short Length of Stay Following Elective Cardiac Surgery in Elderly Patients Using a Genetic Algorithm
    (2013) Lee, Joon; Govindan, Sapna; Celi, Leo A.; Khabbaz, Kamal; Subramaniam, Balachundhar
    Objective: To develop a customized short LOS (<6 days) prediction model for geriatric patients receiving cardiac surgery, using local data and a computational feature selection algorithm. Design: Utilization of a machine learning algorithm in a prospectively collected STS database consisting of patients who received cardiac surgery between January 2002 and June 2011. Setting: Urban tertiary-care center. Participants: Geriatric patients aged 70 years or older at the time of cardiac surgery. Interventions None. Measurements and Main Results Predefined morbidity and mortality events were collected from the STS database. 23 clinically relevant predictors were investigated for short LOS prediction with a genetic algorithm (GenAlg) in 1426 patients. Due to the absence of an STS model for their particular surgery type, STS risk scores were unavailable for 771 patients. STS prediction achieved an AUC of 0.629 while the GenAlg achieved AUCs of 0.573 (in those with STS scores) and 0.691 (in those without STS scores). Among the patients with STS scores, the GenAlg features significantly associated with shorter LOS were absence of congestive heart failure (CHF) (OR = 0.59, p = 0.04), aortic valve procedure (OR = 1.54, p = 0.04), and shorter cross clamp time (OR = 0.99, p = 0.004). In those without STS prediction, short LOS was significantly correlated with younger age (OR = 0.93, p < 0.001), absence of CHF (OR = 0.53, p = 0.007), no preoperative use of beta blockers (OR = 0.66, p = 0.03), and shorter cross clamp time (OR = 0.99, p < 0.001). Conclusion: While the GenAlg-based models did not outperform STS prediction for patients with STS risk scores, our local-data-driven approach reliably predicted short LOS for cardiac surgery types that do not allow STS risk calculation. We advocate that each institution with sufficient observational data should build their own cardiac surgery risk models.
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    Preliminary Biomarkers for Identification of Human Ascending Thoracic Aortic Aneurysm
    (Blackwell Publishing Ltd, 2013) Black, Kendra M.; Masuzawa, Akihiro; Hagberg, Robert C.; Khabbaz, Kamal; Trovato, Mary E.; Rettagliati, Verna M.; Bhasin, Manoj; Dillon, Simon; Libermann, Towia; Toumpoulis, Ioannis K.; Levitsky, Sidney; McCully, James
    Background: Human ascending thoracic aortic aneurysms (ATAAs) are life threatening and constitute a leading cause of mortality in the United States. Previously, we demonstrated that collagens α2(V) and α1(XI) mRNA and protein expression levels are significantly increased in ATAAs. Methods and Results: In this report, the authors extended these preliminary studies using high‐throughput proteomic analysis to identify additional biomarkers for use in whole blood real‐time RT‐PCR analysis to allow for the identification of ATAAs before dissection or rupture. Human ATAA samples were obtained from male and female patients aged 65±14 years. Both bicuspid and tricuspid aortic valve patients were included and compared with nonaneurysmal aortas (mean diameter 2.3 cm). Five biomarkers were identified as being suitable for detection and identification of ATAAs using qRT‐PCR analysis of whole blood. Analysis of 41 samples (19 small, 13 medium‐sized, and 9 large ATAAs) demonstrated the overexpression of 3 of these transcript biomarkers correctly identified 79.4% of patients with ATAA of ≥4.0 cm (P<0.001, sensitivity 0.79, CI=0.62 to 0.91; specificity 1.00, 95% CI=0.42 to 1.00). Conclusion: A preliminary transcript biomarker panel for the identification of ATAAs using whole blood qRT‐PCR analysis in men and women is presented.
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    Predicting DNA methylation level across human tissues
    (Oxford University Press, 2014) Ma, Baoshan; Wilker, Elissa; Willis-Owen, Saffron A. G.; Byun, Hyang-Min; Wong, Kenny C. C.; Motta, Valeria; Baccarelli, Andrea A.; Schwartz, Joel; Cookson, William O. C. M.; Khabbaz, Kamal; Mittleman, Murray; Moffatt, Miriam F.; Liang, Liming
    Differences in methylation across tissues are critical to cell differentiation and are key to understanding the role of epigenetics in complex diseases. In this investigation, we found that locus-specific methylation differences between tissues are highly consistent across individuals. We developed a novel statistical model to predict locus-specific methylation in target tissue based on methylation in surrogate tissue. The method was evaluated in publicly available data and in two studies using the latest IlluminaBeadChips: a childhood asthma study with methylation measured in both peripheral blood leukocytes (PBL) and lymphoblastoid cell lines; and a study of postoperative atrial fibrillation with methylation in PBL, atrium and artery. We found that our method can greatly improve accuracy of cross-tissue prediction at CpG sites that are variable in the target tissue [R2 increases from 0.38 (original R2 between tissues) to 0.89 for PBL-to-artery prediction; from 0.39 to 0.95 for PBL-to-atrium; and from 0.81 to 0.98 for lymphoblastoid cell line-to-PBL based on cross-validation, and confirmed using cross-study prediction]. An extended model with multiple CpGs further improved performance. Our results suggest that large-scale epidemiology studies using easy-to-access surrogate tissues (e.g. blood) could be recalibrated to improve understanding of epigenetics in hard-to-access tissues (e.g. atrium) and might enable non-invasive disease screening using epigenetic profiles.
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    Early Cellular Changes in the Ascending Aorta and Myocardium in a Swine Model of Metabolic Syndrome
    (Public Library of Science, 2016) Saraf, Rabya; Huang, Thomas; Mahmood, Feroze; Owais, Khurram; Bardia, Amit; Khabbaz, Kamal; Liu, David; Senthilnathan, Venkatachalam; Lassaletta, Antonio D.; Sellke, Frank; Matyal, Robina
    Background: Metabolic syndrome is associated with pathological remodeling of the heart and adjacent vessels. The early biochemical and cellular changes underlying the vascular damage are not fully understood. In this study, we sought to establish the nature, extent, and initial timeline of cytochemical derangements underlying reduced ventriculo-arterial compliance in a swine model of metabolic syndrome. Methods: Yorkshire swine (n = 8 per group) were fed a normal diet (ND) or a high-cholesterol (HCD) for 12 weeks. Myocardial function and blood flow was assessed before harvesting the heart. Immuno-blotting and immuno-histochemical staining were used to assess the cellular changes in the myocardium, ascending aorta and left anterior descending artery (LAD). Results: There was significant increase in body mass index, blood glucose and mean arterial pressures (p = 0.002, p = 0.001 and p = 0.024 respectively) in HCD group. At the cellular level there was significant increase in anti-apoptotic factors p-Akt (p = 0.007 and p = 0.002) and Bcl-xL (p = 0.05 and p = 0.01) in the HCD aorta and myocardium, respectively. Pro-fibrotic markers TGF-β (p = 0.01), pSmad1/5 (p = 0.03) and MMP-9 (p = 0.005) were significantly increased in the HCD aorta. The levels of pro-apoptotic p38MAPK, Apaf-1 and cleaved Caspase3 were significantly increased in aorta of HCD (p = 0.03, p = 0.04 and p = 0.007 respectively). Similar changes in coronary arteries were not observed in either group. Functionally, the high cholesterol diet resulted in significant increase in ventricular end systolic pressure and–dp/dt (p = 0.05 and p = 0.007 respectively) in the HCD group. Conclusion: Preclinical metabolic syndrome initiates pro-apoptosis and pro-fibrosis pathways in the heart and ascending aorta, while sparing coronary arteries at this early stage of dietary modification.
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    Artificial Intelligence in Mitral Valve Analysis
    (Medknow Publications & Media Pvt Ltd, 2017) Jeganathan, Jelliffe; Knio, Ziyad; Amador, Yannis; Hai, Ting; Khamooshian, Arash; Matyal, Robina; Khabbaz, Kamal; Mahmood, Feroze
    Background: Echocardiographic analysis of mitral valve (MV) has become essential for diagnosis and management of patients with MV disease. Currently, the various software used for MV analysis require manual input and are prone to interobserver variability in the measurements. Aim: The aim of this study is to determine the interobserver variability in an automated software that uses artificial intelligence for MV analysis. Settings and Design: Retrospective analysis of intraoperative three-dimensional transesophageal echocardiography data acquired from four patients with normal MV undergoing coronary artery bypass graft surgery in a tertiary hospital. Materials and Methods: Echocardiographic data were analyzed using the eSie Valve Software (Siemens Healthcare, Mountain View, CA, USA). Three examiners analyzed three end-systolic (ES) frames from each of the four patients. A total of 36 ES frames were analyzed and included in the study. Statistical Analysis: A multiple mixed-effects ANOVA model was constructed to determine if the examiner, the patient, and the loop had a significant effect on the average value of each parameter. A Bonferroni correction was used to correct for multiple comparisons, and P = 0.0083 was considered to be significant. Results: Examiners did not have an effect on any of the six parameters tested. Patient and loop had an effect on the average parameter value for each of the six parameters as expected (P < 0.0083 for both). Conclusion: We were able to conclude that using automated analysis, it is possible to obtain results with good reproducibility, which only requires minimal user intervention.
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    Making three-dimensional echocardiography more tangible: a workflow for three-dimensional printing with echocardiographic data
    (Bioscientifica Ltd, 2016) Mashari, Azad; Montealegre-Gallegos, Mario; Knio, Ziyad; Yeh, Lu; Jeganathan, Jelliffe; Matyal, Robina; Khabbaz, Kamal; Mahmood, Feroze
    Three-dimensional (3D) printing is a rapidly evolving technology with several potential applications in the diagnosis and management of cardiac disease. Recently, 3D printing (i.e. rapid prototyping) derived from 3D transesophageal echocardiography (TEE) has become possible. Due to the multiple steps involved and the specific equipment required for each step, it might be difficult to start implementing echocardiography-derived 3D printing in a clinical setting. In this review, we provide an overview of this process, including its logistics and organization of tools and materials, 3D TEE image acquisition strategies, data export, format conversion, segmentation, and printing. Generation of patient-specific models of cardiac anatomy from echocardiographic data is a feasible, practical application of 3D printing technology.
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    Dynamic 3-Dimensional Echocardiographic Assessment of Mitral Annular Geometry in Patients With Functional Mitral Regurgitation
    (Elsevier BV, 2013) Khabbaz, Kamal; Mahmood, Feroze-Ud-Den; Shakil, Omair; Warraich, Haider J.; Gorman, Joseph H.; Gorman, Robert C.; Matyal, Robina; Panzica, Peter; Hess, Philip
    Background: Mitral valve (MV) annular dynamics have been well described in animal models of functional mitral regurgitation (FMR). Despite this little, if any, data exists regarding the dynamic MV annular geometry in humans with FMR. In the current study we hypothesized that three-dimensional (3D) echocardiography, in conjunction with commercially available software, could be used to quantify the dynamic changes in MV annular geometry associated with FMR. Methods: Intraoperative 3D transesophageal echocardiographic data obtained from 34 patients with FMR and 15 controls undergoing cardiac surgery were dynamically analyzed for differences in mitral annular geometry with TomTec© 4D MV Assessment 2.0 software. Results: In patients with FMR, the mean mitral annular area (14.6cm2 vs. 9.6cm2), circumference (14.1cm vs. 11.4 cm), anteroposterior (4.0cm vs. 3.0cm) and anterolateral-posteromedial (4.3cm vs. 3.6cm) diameters, tenting volume (6.2mm3 vs. 3.5mm3) and nonplanarity angle (154° ± 15 vs. 136° ± 11) were greater at all points during systole compared to controls (p<0.01). Vertical mitral annular displacement (5.8mm vs. 8.3mm) was reduced in FMR compared to controls (p<0.01). Conclusions: There are significant differences in dynamic mitral annular geometry between patients with and without FMR. We were able to analyze these changes in a clinically feasible fashion. Ready availability of this information has the potential to aid comprehensive quantification of mitral annular function and possibly assist in both clinical decision-making and annuloplasty ring selection.