Stamatios Lerakis

Georgia Institute of Technology, Atlanta, GA, United States

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Publications (129)369.83 Total impact

  • Circulation 04/2014; 129(14):e430-1. · 15.20 Impact Factor
  • John Palios, Stephen Clements, Stamatios Lerakis
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    ABSTRACT: Based on a case of suspected ischemic heart disease we review hiatal hernia causing chest pain. Rest echocardiography images were suggestive of cardiac mass in the left atrium. Dobutamine stress echocardiogram was negative for inducible ischemia. Multi-slice computed tomography of the chest was performed showing that a large hiatal hernia was present compressing on the left atrium. Multimodality imaging is necessary for suspected mass compressing the heart, causing chest discomfort.
    Acute Cardiac Care 03/2014;
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    ABSTRACT: : The role of high-density lipoprotein (HDL) in cardiovascular atheroprotection is well established. Epidemiological data have clearly demonstrated an inverse relationship between HDL levels and the risk for coronary artery disease, which is independent of the low-density lipoprotein levels. However, more recent data provide evidence that high HDL levels are not always protective and that under certain conditions may even confer an increased risk. Thus, a new concept has arisen, which stresses the importance of HDL functionality, rather than HDL concentration per se, in the assessment of cardiovascular risk. HDL functionality is genetically defined but can also be modified by several environmental and lifestyle factors, such as diet, smoking or certain pharmacologic interventions. Furthermore, HDL is consisted of a heterogeneous group of particles with major differences in their structural, biological and functional properties. Recently, the cholesterol efflux capacity from macrophages was proven to be an excellent metric of HDL functionality, because it was shown to have a strong inverse relationship with the risk of angiographically documented coronary artery disease, independent of the HDL and apolipoprotein A-1 levels, although it may not actually predict the prospective risk for cardiovascular events. Thus, improving the quality of HDL may represent a better therapeutic target than simply raising the HDL level, and assessment of HDL function may prove informative in refining our understanding of HDL-mediated atheroprotection.
    The American Journal of the Medical Sciences 03/2014; · 1.33 Impact Factor
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    ABSTRACT: Coronary artery disease (CAD) is the leading cause of death in the United States. Although CAD was formerly considered a lipid accumulation-mediated disease, it has now been clearly shown to involve an ongoing inflammatory response. Advances in basic science research have established the crucial role of inflammation in mediating all stages of CAD. Today, there is convincing evidence that multiple inter-related immune mechanisms interact with metabolic risk factors to initiate, promote and ultimately activate lesions in the coronary arteries. This review aims to provide current evidence pertaining to the role of inflammation in the pathogenesis of CAD and discusses the impact of inflammatory markers and their modification on clinical outcomes.
    Cardiology in review 01/2014;
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    Circulation 01/2014; 129(2):244-53. · 15.20 Impact Factor
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    ABSTRACT: The role of cardiac magnetic resonance (CMR) in coronary artery disease is prominent. CMR provides functional and structural heart disease assessment with high accuracy. It allows accurate cardiac volume and flow quantification and wall motion analysis both at rest and at stress. CMR myocardial perfusion studies detect myocardial ischemia and provide insights into the morphology of the myocardial tissue. CMR imaging noninvasively differentiates causes of myocardial injury such as ischemia or inflammation; stages of myocardial injury, such as acute or chronic; grade of myocardial damage, such as reversible or irreversible; myocardial fibrosis or scar. There is an emerging role of CMR in patients with acute chest presentation since it can demonstrate causes of chest pain other than coronary artery disease such as myocarditis, pericarditis, aortic dissection and pulmonary embolism. CMR is noninvasive and radiation-free. It's combined approach of functional and structural cardiac assessment makes it unique compared with other imaging modalities.
    Expert Review of Cardiovascular Therapy 01/2014;
  • Echocardiography 10/2013; · 1.26 Impact Factor
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    ABSTRACT: Transcatheter aortic valve replacement (TAVR) is an effective treatment in patients with severe aortic stenosis unsuitable for surgical aortic valve replacement (SAVR). This study evaluated the early experience with the posttrial application of TAVR, with specific focus on non-transfemoral (TF) access. All patients who underwent posttrial TAVR at Emory University from November 2011 to April 2012 were reviewed. During this time, 44 posttrial TAVRs were performed: TF in 18, transapical in 11, transaortic in 12, and transcarotid in 3. A total of 40.9% of all patients were candidates for TF implantation. Mean age was 78.2 ± 11.3 years, and 34.1% were women. Mean ejection fraction was 0.463 ± 0.164, and 90.2% had New York Heart Association class III to IV heart failure. Fifty percent were diabetic, 27.3% had moderate to severe chronic obstructive pulmonary disease, and 20.5% had a prior stroke. The mean creatinine was 1.63 ± 1.74 mg/dL, 9.1% required preoperative dialysis, and 61.4% had undergone prior cardiac operations. No patients had postoperative myocardial infarction, stroke, or required new dialysis. Intraoperative vascular complications occurred in 11.4%. No patient had more than mild perivalvular leak by transthoracic echocardiography at discharge. Mean postoperative ventilator time was 17.8 ± 40.1 hours. Intensive care unit length of stay was 58.0 ± 67.0 hours. Postoperative hospital length of stay was 6.1 ± 4.7 days. The 30-day mortality was 6.8% (3 of 44) for all patients, despite a mean The Society of Thoracic Surgeons Predicted Risk of Mortality score of 12.6. Less than half of patients deemed appropriate for posttrial TAVR were candidates for TF implantation. The use of all available access routes leads to excellent outcomes in patients deemed inoperable.
    The Annals of thoracic surgery 08/2013; · 3.74 Impact Factor
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    ABSTRACT: To evaluate the main baseline and procedural characteristics, management and clinical outcomes of patients from a large cohort of patients undergoing transcatheter aortic valve implantation (TAVI) who suffered coronary obstruction (CO). Very few data exist on CO following TAVI. This multicenter registry included a total of 44 patients who suffered symptomatic CO following TAVI of 6,688 patients (0.66%). Pre-TAVI computed tomography data was available in 28 CO patients and in a control group of 345 patients (comparisons were performed including all patients and a cohort matched 1:1 by age, gender, prior CABG, transcatheter valve type and size). Baseline and procedural variables associated with CO were older age (p<0.001), female sex (p<0.001), no prior CABG (p=0.043), the use of a balloon-expandable valve (p=0.023), and prior surgical aortic bioprosthesis (p=0.045). The left coronary artery (LCA) was the one most commonly involved (88.6%). The mean LCA ostia height and sinus of Valsalva (SOV) diameters were lower in patients with obstruction compared to matched controls (10.7±0.4mm vs. 13.3±0.3mm, OR: 2.17, 95%CI 1.62-2.90, and 28.3±0.8mm vs. 31.3±0.6mm, OR: 1.37, 95%CI 1.13-1.66). Most patients presented with persistent severe hypotension (68.2%) and ECG changes (56.8%). Percutaneous coronary intervention was attempted in 75% of the cases, being successful in 81.8%. Thirty-day mortality was of 40.9%. After a median follow-up of 12 (2-18) months, the cumulative mortality rate was of 45.5% and there were no cases of stent thrombosis or reintervention. Symptomatic CO following TAVI was a rare but life-threatening complication that occurred more frequently in women, in patients receiving a balloon-expandable valve, and in those with a prior surgical bioprosthesis. Lower lying coronary ostium and shallow SOV were associated anatomic factors, and despite successful treatment, acute and late mortality remained very high, highlighting the importance of anticipating and preventing the occurrence of this complication.
    Journal of the American College of Cardiology 08/2013; · 14.09 Impact Factor
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    ABSTRACT: : Coronary heart disease (CHD) is one of the leading causes of death in the United States. Traditional risk factors such as family history, hypertension, hypercholesterolemia, diabetes mellitus and smoking cannot account for the entire risk for incident coronary events. Several other potential risk factors have been identified in an effort to improve risk assessment for CHD. This article reviews the current evidence on new and emerging risk factors for CHD and their current utility in screening, specifically focusing on coronary artery calcium score, C-reactive protein, lipoprotein (a), carotid intima-media thickness, homocysteine, lipoprotein-associated phospholipase A2, as well as high-density lipoprotein functionality.
    The American Journal of the Medical Sciences 05/2013; · 1.33 Impact Factor
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    International journal of cardiology 04/2013; · 7.08 Impact Factor
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    ABSTRACT: Pulmonary arterial hypertension (PAH) results in increased right ventricle (RV) afterload leading to RV remodeling, tricuspid regurgitation (TR), and RV failure. Though characterizing the mechanisms of TR in PAH may suggest new treatment strategies, the mechanisms leading to TR in PAH have not been characterized. In the present study, eleven porcine tricuspid valves were studied in an in vitro right heart simulator. Annular dilatations of 1.2 and 1.4 times normal area, papillary muscle (PM) displacement simulating concentric RV dilatation and eccentric RV dilatation due to concomitant left ventricle dysfunction, and two levels of PAH hemodynamics were simulated independently and in combination. Relative TR, tenting area (TA) along each coaptation line, and coaptation area (CA) of each leaflet were quantified. Results showed a significant increase (p ≤ 0.05) in TR with both increased mean pulmonary artery pressure (mPAP) and annular dilatation of 1.4 times normal. Increased mPAP significantly decreased TA but tended to increase CA, while PM displacement significantly increased TA but did not affect CA, suggesting competing effects of transvalvular pressure and leaflet tethering. Annular dilatation significantly decreased anterior and posterior CA but did not affect TA. These results may inform future TV repairs in PAH to reduce TR and improve RV hemodynamics.
    Annals of biomedical engineering 04/2013; 41(4):709-24. · 2.41 Impact Factor
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    ABSTRACT: Patient-specific models of the heart's mitral valve (MV) exhibit potential for surgical planning. While advances in 3D echocardiography (3DE) have provided adequate resolution to extract MV leaflet geometry, no study has quantitatively assessed the accuracy of their modeled leaflets vs. a ground-truth standard for temporal frames beyond systolic closure or for differing valvular dysfunctions. The accuracy of a 3DE-based segmentation methodology based on J-splines was assessed for porcine MVs with known 4D leaflet coordinates within a pulsatile simulator during closure, peak closure, and opening for a control, prolapsed, and billowing MV model. For all time points, the mean distance error between the segmented models and ground-truth data were 0.40 ± 0.32 mm, 0.52 ± 0.51 mm, and 0.74 ± 0.69 mm for the control, flail, and billowing models. For all models and temporal frames, 95% of the distance errors were below 1.64 mm. When applied to a patient data set, segmentation was able to confirm a regurgitant orifice and post-operative improvements in coaptation. This study provides an experimental platform for assessing the accuracy of an MV segmentation methodology at phases beyond systolic closure and for differing MV dysfunctions. Results demonstrate the accuracy of a MV segmentation methodology for the development of future surgical planning tools.
    Annals of biomedical engineering 03/2013; · 2.41 Impact Factor
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    ABSTRACT: BACKGROUND: Multicenter clinical trials use echocardiographic core laboratories to ensure expertise and consistency in the assessment of imaging eligibility criteria, as well as safety and efficacy end points. The aim of this study was to report the real-world implementation of guidelines for best practices in echocardiographic core laboratories, including their feasibility and quality results, in a large, international multicenter trial. METHODS: Processes and procedures were developed to optimize the acquisition and analysis of echocardiograms for the Placement of Aortic Transcatheter Valves (PARTNER) I trial of percutaneous aortic valve replacement for aortic stenosis. Comparison of baseline findings in the operative and nonoperative cohorts and reproducibility analyses were performed. RESULTS: Echocardiography was performed in 1,055 patients (mean age, 83 years; 54% men) The average peak and mean aortic valve gradients were 73 ± 24 and 43 ± 15 mm Hg, and the average aortic valve area was 0.64 ± 0.20 cm2. The average ejection fraction was 52 ± 13% by visual estimation and 53 ± 14% by biplane planimetry. The mean left ventricular mass index was 151 ± 42 g/m2. The inoperable cohort had lower left ventricular mass and mass indexes and tended to have more severe mitral regurgitation. Core lab reproducibility was excellent, with intraclass correlation coefficients ranging from 0.92 to 0.99 and κ statistics from 0.58 to 0.85 for key variables. The image acquisition quality improvement process brought measurability to >85%, which was maintained for the duration of the study. CONCLUSIONS: This real-world echocardiographic core lab experience in the PARTNER I trial demonstrates that a high standard of measurability and reproducibility can result from extensive quality assurance efforts in both image acquisition and analysis. These results and the echocardiographic data reported here provide a reference for future studies of aortic stenosis patients and should encourage the wider use of echocardiography in clinical research.
    Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography 03/2013; · 2.98 Impact Factor
  • Stamatios Lerakis, Salim S Hayek, Pamela S Douglas
    Circulation 01/2013; 127(3):397-407. · 15.20 Impact Factor
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    ABSTRACT: Percutaneous patent foramen ovale (PFO) closure is a treatment for cryptogenic stroke (CS) and migraine headache. The goal of this study was to assess long-term outcomes of patients treated with percutaneous PFO closure. Records of patients with percutaneous PFO closure at Emory University Hospital from February 2002 to July 2009 were reviewed. Follow-up telephone questionnaire and chart review assessed recurrent stroke, migraine, and complications. Data was reviewed on 414 consecutive patients. Long-term follow-up was obtained in 207 of patients, and mean follow up was 4.6 ± 2.0 years. CS was the primary indication for intervention in 193 (93%) patients. Thirteen (7%) patients had a recurrent neurologic event post closure. In patients with multiple neurological events at baseline, 17% (n = 11) had a recurrent event, compared with 2% (n = 2) of patients with a single neurological event prior to PFO-closure (P < 0.002). Post closure, migraine frequency and severity declined from 4.5 to 1.1 migraine/month (P < 0.01) and 7.2 to 3.6 out of 10 (P < 0.01) in patients with history of migraine (n = 60). Thirty-day mortality was 1% (n = 2). One patient had device erosion 5 years post-procedure requiring emergent surgery. Atrial fibrillation was newly diagnosed in 8 (4%) patients within 6 months. In conclusion, the long-term rate of recurrent stroke after PFO closure is low in patients with a single neurological event at baseline. Serious long-term complications after PFO closure are rare. PFO closure may decrease the frequency and severity of migraine.
    The American Journal of the Medical Sciences 01/2013; · 1.33 Impact Factor
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    Journal of Cardiovascular Magnetic Resonance 01/2013; 15(1). · 4.44 Impact Factor
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    Journal of Cardiovascular Magnetic Resonance 01/2013; 15(1). · 4.44 Impact Factor
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    ABSTRACT: We report three patients who had successful transcatheter aortic valve replacement (TAVR) via carotid artery access. None were candidates for thoracotomy (including minimal access incisions) and had no other vascular access sites that would accommodate the transcatheter valve sheath. Antegrade carotid perfusion and retrograde insertion of the delivery sheath maintained cerebral blood flow without sequelae. Carotid access for TAVR is an option for unusual patients without other access. © 2012 Wiley Periodicals, Inc.
    Catheterization and Cardiovascular Interventions 08/2012; · 2.51 Impact Factor
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    ABSTRACT: Patients who present with significant paravalvular regurgitation after mitral valve replacement remain a difficult patient population and high-risk surgical candidates. We present 3 cases of transapical closure of mitral valve paravalvular leak (PVL) after mitral valve replacement using Amplatzer closure devices (AGA Medical Corp, Plymouth, MN). All 3 patients experienced decreased regurgitation at the site of the closure as well as symptomatic improvement in their heart failure.
    The Annals of thoracic surgery 07/2012; 94(1):275-8. · 3.74 Impact Factor

Publication Stats

690 Citations
369.83 Total Impact Points


  • 2013
    • Georgia Institute of Technology
      • Department of Biomedical Engineering
      Atlanta, GA, United States
  • 2003–2012
    • Emory University
      • • Department of Radiology
      • • Division of Cardiology
      • • Division of Pulmonary, Allergy and Critical Care Medicine
      Atlanta, GA, United States
  • 2008–2011
    • Hippokration General Hospital, Athens
      Athínai, Attica, Greece
  • 2010
    • Johns Hopkins Medicine
      • Department of Medicine
      Baltimore, MD, United States
  • 2007
    • Attikon University Hospital
      • Department of Internal Medicine IV
      Athínai, Attica, Greece
  • 2004–2005
    • University of Texas at San Antonio
      • Department of Mechanical Engineering
      San Antonio, TX, United States
  • 1997
    • University of Texas Medical Branch at Galveston
      • Division of Cardiology
      Galveston, Texas, United States