Stamatios Lerakis

Emory University, Atlanta, Georgia, United States

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Publications (195)889.78 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Chronic obstructive pulmonary disease (COPD) has been identified as a risk factor for morbidity and mortality after transcatheter aortic valve replacement (TAVR). We hypothesized that a portion of pulmonary dysfunction in patients with severe aortic stenosis may be of cardiac origin, and has potential to improve after TAVR. A retrospective analysis was made of consecutive TAVR patients from April 2008 to October 2014. Of patients who had pulmonary function testing and serum B-type natriuretic peptide data available before and after TAVR, 58 were found to have COPD (26 mild, 14 moderate, and 18 severe). Baseline variables and operative outcomes were explored along with changes in pulmonary function. Multiple regression analyses were performed to adjust for preoperative left ventricular ejection fraction and glomerular filtration rate. Comparison of pulmonary function testing before and after the procedure among all COPD categories showed a 10% improvement in forced vital capacity (95% confidence interval: 4% to 17%) and a 12% improvement in forced expiratory volume in 1 second (95% confidence interval: 6% to 19%). There was a 29% decrease in B-type natriuretic peptide after TAVR (95% confidence interval: -40% to -16%). An improvement of at least one COPD severity category was observed in 27% of patients with mild COPD, 64% of patients with moderate COPD, and 50% of patients with severe COPD. There was no 30-day mortality in any patient group. In patients with severe aortic stenosis, TAVR is associated with a significant improvement of pulmonary function and B-type natriuretic peptide. After TAVR, the reduction in COPD severity was most evident in patients with moderate and severe pulmonary dysfunction. Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.
    The Annals of thoracic surgery 08/2015; DOI:10.1016/j.athoracsur.2015.06.008 · 3.85 Impact Factor
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    ABSTRACT: Objectives: To investigate the hemodynamic performance of a transcatheter heart valve (THV) deployed at different valve-in-valve (VIV) positions in an in-vitro model using a small surgical bioprosthesis. Background: High surgical risk patients with a failing 19 mm surgical aortic bioprosthesis are not candidates for a VIV transcatheter aortic valve replacement (TAVR) due to risk of high transvalvular pressure gradients (TVPG) and patient-prosthesis mismatch (PPM). Methods: A 19 mm stented aortic bioprosthesis was mounted into the aortic chamber of a pulse duplicator and a 23 mm low profile balloon-expandable THV was deployed (valve-in-valve) in 4 positions: normal (bottom of the THV stent aligned with the bottom of the surgical bioprosthesis sewing ring); and 3 mm, 6 mm, and 8 mm above the normal position. Under controlled hemodynamics, the effect of these THV positions on valve performance (mean TVPG, geometric orifice area (GOA), and effective orifice are (EOA)), thrombotic potential (sinus shear stress), and migration risk (pullout force and embolization flow rate) were assessed. Results: Compared to normal implantation, a progressive reduction of mean TVPG was observed with each supra-annular THV position (normal: 33.10 mmHg, 3 mm: 24.69 mmHg, 6 mm: 19.16 mmHg, and 8 mm: 12.98 mmHg; p=<0.001). Simultaneously, we observed an increase in GOA (normal: 0.83 cm2 vs. 8 mm: 1.60 cm2; p=<0.001) and EOA (normal: 0.80 cm2 vs. 8 mm: 1.28 cm2; p=<0.001), and reduction in sinus shear stresses (normal: 153 dyne/cm2 vs. 8 mm: 40 dyne/cm2; p=<0.001), pullout forces (normal: 1.55 N vs. 8 mm: 0.68 N; p<0.05), and embolization flow rates (normal: 32.91 L/min vs. 8 mm: 26.06 L/min; p<0.01). Conclusions: Supra-annular implantation of a THV in a small surgical bioprosthesis reduces mean TVPG, but may increase risk of leaflet thrombosis and valve migration. A 3-6 mm supraannular deployment could be an optimal position in these cases.
    JACC Cardiovascular Interventions 08/2015; · 7.35 Impact Factor
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    ABSTRACT: Aortic valve stenosis is the most common valvular disease in the elderly population. Presently, there is increasing evidence that aortic stenosis (AS) is an active process of lipid deposition, inflammation, fibrosis and calcium deposition. The pathogenesis of AS shares many similarities to that of atherosclerosis; therefore, it was hypothesized that certain lipid interventions could prevent or slow the progression of aortic valve stenosis. Despite the early enthusiasm that statins may slow the progression of AS, recent large clinical trials did not consistently demonstrate a decrease in the progression of AS. However, some researchers believe that statins may have a benefit early on in the disease process, where inflammation (and not calcification) is the predominant process, in contrast to severe or advanced AS, where calcification (and not inflammation) predominates. Positron emission tomography using 18F-fluorodeoxyglucose and 18F-sodium fluoride can demonstrate the relative contributions of valvular calcification and inflammation in AS, and thus this method might potentially be useful in providing the answer as to whether lipid interventions at the earlier stages of AS would be more effective in slowing the progression of the disease. Currently, there is a strong interest in recombinant apolipoprotein A-1 Milano and in the development of new pharmacological agents, targeting reduction of lipoprotein (a) levels and possibly reduction of the expression of lipoprotein-associated phospholipase A2, as potential means to slow the progression of aortic valvular stenosis.
    The American Journal of the Medical Sciences 08/2015; DOI:10.1097/MAJ.0000000000000544 · 1.39 Impact Factor
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    ABSTRACT: A minimalist approach for transcatheter aortic valve replacement (MA-TAVR) utilizing transfemoral access under conscious sedation and transthoracic echocardiography is increasing in popularity. This relatively novel technique may necessitate a learning period to achieve proficiency in performing a successful and safe procedure. This report evaluates our MA-TAVR cohort with specific characterization between our early, midterm, and recent experience. We retrospectively reviewed 151 consecutive patients who underwent MA-TAVR with surgeons and interventionists equally as primary operator at Emory University between May 2012 and July 2014. Our institution had performed 300 TAVR procedures before implementation of MA-TAVR. Patient characteristics and early outcomes were compared using Valve Academic Research Consortium 2 definitions among 3 groups: group 1 included the first 50 patients, group 2 included patients 51 to 100, and group 3 included patients 101 to 151. Median age for all patients was 84 years and similar among groups. The majority of patients were men (56%) and the median ejection fraction for all patients was 55% (interquartile range, 38.0%-60.0%). The majority of patients were high-risk surgical candidates with a median Society of Thoracic Surgeons Predicted Risk of Mortality of 10.0% and similar among groups. The overall major stroke rate was 3.3%, major vascular complications occurred in 3% of patients, and greater-than-mild paravalvular leak rate was 7%. In-hospital mortality and morbidity were similar among all 3 groups. In a high-volume TAVR center, transition to MA-TAVR is feasible with acceptable outcomes and a diminutive procedural learning curve. We advocate for TAVR centers to actively pursue the minimalist technique with equal representation by cardiologists and surgeons. Copyright © 2015 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.
    The Journal of thoracic and cardiovascular surgery 07/2015; DOI:10.1016/j.jtcvs.2015.07.078 · 4.17 Impact Factor
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    ABSTRACT: When transcatheter aortic valve replacement (TAVR) cannot be carried out through transfemoral access, alternative access TAVR is indicated. The purpose of this study was to explore inhospital and 1-year outcomes of patients undergoing alternative access TAVR through the transapical (TA) or transaortic (TAo) techniques in the United States. Clinical records of 4,953 patients undergoing TA (n = 4,085) or TAo (n = 868) TAVR from 2011 to 2014 in The Society of Thoracic Surgeons (STS)/American College of Cardiology Transcatheter Valve Therapy Registry were linked to Centers for Medicare and Medicaid Services hospital claims. Inhospital and 1-year clinical outcomes were stratified by operative risk; and the risk-adjusted association between access route and mortality, stroke, and heart failure repeat hospitalization was explored. Mean age for all patients was 82.8 ± 6.8 years. The median STS predicted risk of mortality was significantly higher among patients undergoing TAo (8.8 versus 7.4, p < 0.001). When compared with TA, TAo was associated with an increased risk of unadjusted 30-day mortality (10.3% versus 8.8%) and 1-year mortality (30.3% versus 25.6%, p = 0.006). There were no significant differences between TAo and TA for inhospital stroke rate (2.2%), major vascular complications (0.3%), and 1-year heart failure rehospitalizations (15.7%). Examination of high-risk and inoperable subgroups showed that 1-year mortality was significantly higher for TAo patients classified as inoperable (p = 0.012). Patients undergoing TAo TAVR are older, more likely female, and have significantly higher STS predicted risk of mortality scores than patients operated on by TA access. There were no risk-adjusted differences between TA and TAo access in mortality, stroke, or readmission rates as long as 1 year after TAVR. Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.
    The Annals of thoracic surgery 07/2015; DOI:10.1016/j.athoracsur.2015.05.010 · 3.85 Impact Factor
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    ABSTRACT: Transcatheter aortic valve replacement (TAVR) may offer extreme-aged patients a treatment alternative to surgical aortic valve replacement (SAVR). The objective of this study was to describe outcomes of TAVR in nonagenarians using transfemoral and alternative access techniques. In a retrospective review, we found 95 nonagenarians who underwent TAVR from September 2007 through February 2014 at Emory University using a balloon expandable valve: transfemoral (n = 66), transapical (n = 14), transaortic (n = 14), and transcarotid (n = 1). Morbidity and 30-day and midterm mortality were assessed. Kaplan-Meier plots were used to determine midterm survival rates. The mean age of the patients was 91.8 ± 1.8 years, and 49 (52%) were female. Postoperative morbidity included 1 patient (1%) each with stroke, myocardial infarction, pneumonia, and renal failure. The mean postoperative length of stay was 6.8 ± 5.1 days for all patients. Overall 30-day mortality was 3.2%, much less than The Society of Thoracic Surgeons predicted risk of mortality of 14.5% ± 7.3%. There were no deaths in the transfemoral patients, but there were 2 transapical deaths (14.3%) and 1 transaortic death (7.1%). The Kaplan-Meier estimate of median survival was 2.6 years. Extreme-aged nonagenarian patients may have excellent outcomes from TAVR at 30-day and midterm follow-up. Alternative access TAVR is associated with higher morbidity and mortality than transfemoral TAVR. Referral for TAVR of nonagenarians should not be precluded based on age alone. Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.
    The Annals of thoracic surgery 07/2015; DOI:10.1016/j.athoracsur.2015.04.037 · 3.85 Impact Factor
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    ABSTRACT: Ventriculoarterial coupling (VAC) status relates to tissue perfusion and its optimization may improve organ function and energy efficiency (EE) of the cardiovascular system. The effects of non-invasively calculated VAC improvement on echocardiographic parameters, renal function indices and EE improvement in patients with acute decompensated systolic heart failure were studied. Furthermore, effects of different treatment modalities on VAC, renal function and echocardiographic parameters were compared. Systolic heart failure patients with ejection fraction <50% were studied, who, at the treating physician's discretion, received 8-hour infusions of: high dose furosemide (20mg/h), low dose furosemide (5mg/h) or dopamine (5μg/kg/min) combined with furosemide (5mg/h). Echocardiographic assessments were performed at 0 and 24h. Renal function was evaluated using serum creatinine and creatinine clearance. VAC and EE were assessed noninvasively, by echocardiography. Significant correlations were noted between VAC improvement and improvements in EE and serum creatinine (rho=0.96, p<0.001, rho=0.32, p=0.04 respectively). Dopamine-furosemide combination had a borderline effect on creatinine (p=0.08) and led to significant improvements in e', E/e' ratio (p=0.015 and p=0.009 respectively) and VAC (value closer to 1). VAC improvement correlated with EE and creatinine improvement, regardless of treatment, supporting a potential role for VAC status assessment and improvement in acute decompensated systolic heart failure. Dopamine and furosemide combination seemed to improve VAC and diastolic function but only had a borderline effect on renal function. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
    International journal of cardiology 07/2015; 199:44-49. DOI:10.1016/j.ijcard.2015.06.181 · 4.04 Impact Factor
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    ABSTRACT: Despite marked benefits in many heart failure patients, a considerable proportion of patients treated with cardiac resynchronization therapy (CRT) fail to respond appropriately. Recently, a "U-shaped" (type II) wall motion pattern identified by cardiovascular magnetic resonance (CMR) has been associated with improved CRT response compared to a homogenous (type I) wall motion pattern. There is also evidence that a left ventricular (LV) lead localized to the latest contracting LV site predicts superior response, compared to an LV lead localized remotely from the latest contracting LV site. We prospectively evaluated patients undergoing CRT with pre-procedural CMR to determine the presence of type I and type II wall motion patterns and pre-procedural echocardiography to determine end systolic volume (ESV). We assessed the final LV lead position on post-procedural fluoroscopic images to determine whether the lead was positioned concordant to or remote from the latest contracting LV site. CRT response was defined as a ≥ 15 % reduction in ESV on a 6 month follow-up echocardiogram. The study included 33 patients meeting conventional indications for CRT with a mean New York Heart Association class of 2.8 ± 0.4 and mean LV ejection fraction of 28 ± 9 %. Overall, 55 % of patients were echocardiographic responders by ESV criteria. Patients with both a type II pattern and an LV lead concordant to the latest contracting site (T2CL) had a response rate of 92 %, compared to a response rate of 33 % for those without T2CL (p = 0.003). T2CL was the only independent predictor of response on multivariate analysis (odds ratio 18, 95 % confidence interval 1.6-206; p = 0.018). T2CL resulted in significant incremental improvement in prediction of echocardiographic response (increase in the area under the receiver operator curve from 0.69 to 0.84; p = 0.038). The presence of a type II wall motion pattern on CMR and a concordant LV lead predicts superior CRT response. Improving patient selection by evaluating wall motion pattern and targeting LV lead placement may ultimately improve the response rate to CRT.
    Journal of Cardiovascular Magnetic Resonance 07/2015; 17(1):57. DOI:10.1186/s12968-015-0158-5 · 4.56 Impact Factor
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    ABSTRACT: Pseudoaneurysm of the mitral-aortic intervalvular fibrosa is a rare but serious sequela of endocarditis or valve replacement surgery. Because open-heart surgery is a high-risk treatment option, alternative methods are sought. We present the case of a 77-year-old man with a noninfected mechanical mitral valve whose pseudoaneurysm was repaired by introducing an occluder device into the defect by a transapical approach. Upon follow-up imaging, the defect was successfully closed. We conclude that percutaneous closure of pseudoaneurysm of the mitral-aortic intervalvular fibrosa is a viable alternative to surgery and that a transapical approach is an appropriate method of access.
    Texas Heart Institute journal / from the Texas Heart Institute of St. Luke's Episcopal Hospital, Texas Children's Hospital 06/2015; 42(3):285-288. DOI:10.14503/THIJ-14-4156 · 0.65 Impact Factor
  • BMES/FDA Frontiers in Medical Devices Conference: Innovations in Modeling and Simulation, Washington DC; 05/2015
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    ABSTRACT: OBJECTIVE: Acute aortic regurgitation (AR) is a potential complication of transcatheter aortic valve replacement (TAVR) for severe aortic stenosis (AS). In this work, we hypothesize that the stiffened ventricle, a result of chronic AS, decreases the filling efficiency of the ventricle while increasing the stroke work (SW) required to maintain a healthy forward stroke volume (SV). METHODS: Three left ventricle (LV) models of varying diastolic compliances were inserted into a physiological left heart flow phantom (a) consisting of systemic resistances and compliances tuned to generate physiological flow and pressure conditions (Aortic pressures of 120/80 mmHg, stroke volume of 60 – 70 mL/beat, cardiac output of 4.5 – 5.0 L/min). Valves were placed in the mitral and aortic positions. Different levels of AR, ranging from mild to severe, by were generated preventing proper coaptation of the aortic valve leaflets. Flow rates into and out of the LV along with pressures in the LV and aorta were measured. LV performance and efficiency for all cases were characterized via pressure volume loops. RESULTS: Using a LV with a diastolic compliance of 1.5 cc/mmHg (diastolic compliance of LV post chronic AS, b), the SW was held at a constant 1.07 ± 0.09 J. The volumetric flow through the mitral valve as well as the diastolic period decreased with increasing regurgitant fraction (c, d). The mean LV diastolic pressure increased linearly (5 – 21 mmHg) with increasing regurgitant fraction (0 – 75%, f). At a regurgitant fraction of 33%, it was found that the LV had to work ~25% harder (to raise the SV to 60 mL/beat) in order to compensate for the backflow via the aortic valve (e). CONCLUSIONS: The increase in regurgitant fraction lead to a linear decrease in the effective forward SV, thereby leading to a decrease in the cardiac output. The preliminary results indicate that in the presence of AR, post chronic AS, there is a significant increases in the SW requirement of the LV to obtain a forward SV of 60 – 70 mL/beat.
    Heart Valve Society 2015 Annual Scientific Meeting; 05/2015
  • Heart Valve Society Inaugural Scientific Meeting, Monaco; 05/2015
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    ABSTRACT: Tricuspid regurgitation (TR) and right ventricular (RV) dysfunction adversely affect outcomes in patients with heart failure or mitral valve disease, but their impact on outcomes in patients with aortic stenosis treated with transcatheter aortic valve replacement has not been well characterized. Among 542 patients with symptomatic aortic stenosis treated in the Placement of Aortic Transcatheter Valves (PARTNER) II trial (inoperable cohort) with a Sapien or Sapien XT valve via a transfemoral approach, baseline TR severity, right atrial and RV size and RV function were evaluated by echocardiography according to established guidelines. One-year mortality was 16.9%, 17.2%, 32.6%, and 61.1% for patients with no/trace (n=167), mild (n=205), moderate (n=117), and severe (n=18) TR, respectively (P<0.001). Increasing severity of RV dysfunction as well as right atrial and RV enlargement were also associated with increased mortality (P<0.001). After multivariable adjustment, severe TR (hazard ratio, 3.20; 95% confidence interval, 1.50-6.82; P=0.003) and moderate TR (hazard ratio, 1.60; 95% confidence interval, 1.02-2.52; P=0.042) remained associated with increased mortality as did right atrial and RV enlargement, but not RV dysfunction. There was an interaction between TR and mitral regurgitation severity (P=0.04); the increased hazard of death associated with moderate/severe TR only occurred in those with no/trace/mild mitral regurgitation. In inoperable patients treated with transcatheter aortic valve replacement, moderate or severe TR and right heart enlargement are independently associated with increased 1-year mortality; however, the association between moderate or severe TR and an increased hazard of death was only found in those with minimal mitral regurgitation at baseline. These findings may improve our assessment of anticipated benefit from transcatheter aortic valve replacement and support the need for future studies on TR and the right heart, including whether concomitant treatment of TR in operable but high-risk patients with aortic stenosis is warranted. URL: Unique identifier: NCT01314313. © 2015 American Heart Association, Inc.
    Circulation Cardiovascular Interventions 04/2015; 8(4). DOI:10.1161/CIRCINTERVENTIONS.114.002073 · 6.22 Impact Factor
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    ABSTRACT: Transcatheter aortic valve replacement (TAVR) using a balloon-expandable valve is an accepted alternative to surgical replacement for severe, symptomatic aortic stenosis in high risk or inoperable patients. Intraprocedural transesophageal echocardiography (TEE) offers real-time imaging guidance throughout the procedure and allows for rapid and accurate assessment of complications and procedural results. The value of intraprocedural TEE for TAVR will likely increase in the future as this procedure is performed in lower surgical risk patients, who also have lower risk for general anesthesia, but a greater expectation of optimal results with lower morbidity and mortality. This imaging compendium from the PARTNER (Placement of Aortic Transcatheter Valves) trials is intended to be a comprehensive compilation of intraprocedural complications imaged by intraprocedural TEE and diagnostic tools to anticipate and/or prevent their occurrence. Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.
    JACC Cardiovascular Imaging 03/2015; 8(3). DOI:10.1016/j.jcmg.2014.12.013 · 7.19 Impact Factor
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    ABSTRACT: -We aimed to determine the incidence, predictors, clinical characteristics, management, and outcomes of IE after TAVI. -This multicenter registry included 53 patients (mean age 79±8 years, men: 57%) who suffered IE following TAVI of 7,944 patients after a mean follow-up of 1.1±1.2 years (incidence of 0.67%; 0.50% within the first year post-TAVI). Mean time from TAVI was 6 (IQR: 1-14) months. Orotracheal intubation (HR: 3.87, 95%CI: 1.55-9.64, P=.004) and the self-expandable CoreValve system (HR: 3.12, 95% CI: 1.37-7.14, P=.007) were associated with IE (multivariate analysis including 3067 patients with individual data). The most frequent causal microorganisms were coagulase-negative staphylococci (24%), followed by Staphylococcus aureus (21%) and enterococci (21%). Vegetations were present in 77% of patients (transcatheter valve leaflets: 39%, stent frame: 17%, mitral valve: 21%). At least one complication of IE occurred in 87% of patients (heart failure in 68%). However, only 11% of patients underwent valve intervention (valve explantation and valve-in-valve in 4 and 2 patients, respectively). The in-hospital mortality rate was 47.2%, and increased up to 66% at 1-year follow-up. IE complications such as heart failure (p=0.037) or septic shock (p=0.002) were associated with increased in-hospital mortality. -The incidence of IE at 1-year after TAVI was of 0.50%, and the risk increased with the use of orotracheal intubation and a self-expandable valve system. Staphyloccoci and enteroccoci were the most common agents. While most patients presented at least one complication of IE, valve intervention was performed in a minority of patients, and nearly half of the patients died during the hospitalization period.
    Circulation 03/2015; 131(18). DOI:10.1161/CIRCULATIONAHA.114.014089 · 14.43 Impact Factor
  • Journal of the American College of Cardiology 03/2015; 65(10):A1703. DOI:10.1016/S0735-1097(15)61703-X · 16.50 Impact Factor
  • Journal of the American College of Cardiology 03/2015; 65(10):A1227. DOI:10.1016/S0735-1097(15)61227-X · 16.50 Impact Factor
  • Journal of the American College of Cardiology 03/2015; 65(10):A1882. DOI:10.1016/S0735-1097(15)61882-4 · 16.50 Impact Factor
  • Journal of the American College of Cardiology 03/2015; 65(10):A1086. DOI:10.1016/S0735-1097(15)61086-5 · 16.50 Impact Factor
  • Journal of the American College of Cardiology 03/2015; 65(10):A1998. DOI:10.1016/S0735-1097(15)61998-2 · 16.50 Impact Factor

Publication Stats

2k Citations
889.78 Total Impact Points


  • 2000–2015
    • Emory University
      • • Division of Cardiology
      • • Department of Internal Medicine
      • • School of Medicine
      Atlanta, Georgia, United States
  • 2013–2014
    • Georgia Institute of Technology
      • Department of Biomedical Engineering
      Atlanta, Georgia, United States
  • 2009
    • William Penn University
      Filadelfia, Pennsylvania, United States
  • 1999
    • Texas A&M University - Galveston
      Galveston, Texas, United States
  • 1997
    • University of Texas Medical Branch at Galveston
      • School of Medicine
      Galveston, TX, United States