Tamas Alexy

Dr. Tamas Alexy

Division of Cardiology, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA
orcid

Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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6 July 2022 in Frontiers in Physiology
Verified
Journal Article
Open access
TATamas Alexy
Tamas Alexy
JDJon Detterich
Jon Detterich
PCPhilippe Connes
Philippe Connes
KTKalman Toth
Kalman Toth
ENElie Nader
Elie Nader
MSMichael J. Simmonds
Michael J. Simmonds
It has been long known that blood health heavily influences optimal physiological function. Abnormalities affecting the physical properties of blood have been implicated in the pathogenesis of various disorders, although the exact mechanistic links between hemorheology and clinical disease manifestations remain poorly understood. Often overlooked in current medical practice, perhaps due to the promises offered in the molecular and genetic era, the physical properties of blood which remain a valuable and definitive indicator of circulatory health and disease. Bridging this gap, the current manuscript provides an introduction to hemorheology. It reviews the properties that dictate bulk and microcirculatory flow by systematically dissecting the biomechanics that determine the non-Newtonian behavior of blood. Specifically, the impact of hematocrit, the mechanical properties and tendency of red blood cells to aggregate, and various plasma factors on blood viscosity will be examined. Subsequently, the manner in which the physical properties of blood influence hemodynamics in health and disease is discussed. Special attention is given to disorders such as sickle cell disease, emphasizing the clinical impact of severely abnormal blood rheology. This review expands into concepts that are highly topical; the relation between mechanical stress and intracellular homeostasis is examined through a contemporary cell-signaling lens. Indeed, accumulating evidence demonstrates that nitric oxide is not only transported by erythrocytes, but is locally produced by mechanically-sensitive enzymes, which appears to have intracellular and potentially extracellular effects. Finally, given the importance of shear forces in the developing field of mechanical circulatory support, we review the role of blood rheology in temporary and durable mechanical circulatory support devices, an increasingly utilized method of life support. This review thus provides a comprehensive overview for interested trainees, scientists, and clinicians.

14 August 2024 in JACC: Heart Failure
Verified
Journal Article
Open access
JGJason Leon Guichard
Jason Leon Guichard
EBEric L. Bonno
Eric L. Bonno
MNMichael E. Nassif
Michael E. Nassif
TKTaiyeb M. Khumri
Taiyeb M. Khumri
DMDavid Miranda
David Miranda
LKLiviu Klein
Liviu Klein
Monitoring supine pulmonary artery pressures to guide heart failure (HF) management has reduced HF hospitalizations in select patients. The purpose of this study was to evaluate the effect of managing seated mean pulmonary artery pressure (mPAP) with the Cordella Pulmonary Artery sensor on outcomes in patients with HF. Following GUIDE-HF (Hemodynamic-GUIDEd Management of Heart Failure Trial), with U.S. Food and Drug Administration input, PROACTIVE-HF (A Prospective, Multi-Center, Open Label, Single Arm Clinical Trial Evaluating the Safety and Efficacy of the Cordella Pulmonary Artery Sensor System in NYHA Class III Heart Failure Patients trial) was changed from a randomized to a single-arm, open label trial, conducted at 75 centers in the USA and Europe. Eligible patients had chronic HF with NYHA functional class III symptoms, irrespective of the ejection fraction, and recent HF hospitalization and/or elevated natriuretic peptides. The primary effectiveness endpoint at 6 months required the HF hospitalization or all-cause mortality rate to be lower than a performance goal of 0.43 events/patient, established from previous hemodynamic monitoring trials. Primary safety endpoints at 6 months were freedom from device- or system-related complications or pressure sensor failure. Between February 7, 2020, and March 31, 2023, 456 patients were successfully implanted in modified intent-to-treat cohort. The 6-month event rate was 0.15 (95% CI: 0.12-0.20) which was significantly lower than performance goal (0.15 vs 0.43; P < 0.0001). Freedom from device- or system-related complications was 99.2% and freedom from sensor failure was 99.8% through 6 months. Remote management of seated mPAP is safe and results in a low rate of HF hospitalizations and mortality. These results support the use of seated mPAP monitoring and extend the growing body of evidence that pulmonary artery pressure-guided management improves outcomes in heart failure. (Multi-Center, Open Label, Single Arm Clinical Trial Evaluating the Safety and Efficacy of the Cordella Pulmonary Artery Sensor System in NYHA Class III Heart Failure Patients trial [PROACTIVE-HF]; NCT04089059).

25 October 2023 in Biomedicines
Verified
Journal Article
Open access
PDF file
RGRoland Gal
Roland Gal
RHRobert Halmosi
Robert Halmosi
Ferenc GallyasFerenc Gallyas
Ferenc Gallyas
MTMichael Tschida
Michael Tschida
PMPornthira Mutirangura
Pornthira Mutirangura
László CzopfLászló Czopf
László Czopf
Cardiovascular diseases (CVDs) are among the leading causes of morbidity and mortality worldwide. Unhealthy dietary habits have clearly been shown to contribute to the development of CVDs. Beyond the primary nutrients, a healthy diet is also rich in plant-derived compounds. Natural polyphenols, found in fruits, vegetables, and red wine, have a clear role in improving cardiovascular health. In this review, we strive to summarize the results of the relevant pre-clinical and clinical trials that focused on some of the most important natural polyphenols, such as resveratrol and relevant flavonoids. In addition, we aim to identify their common sources, biosynthesis, and describe their mechanism of action including their regulatory effect on signal transduction pathways. Finally, we provide scientific evidence regarding the cardiovascular benefits of moderate, long-term red wine consumption.

9 December 2020 in Medicina
Verified
Journal Article
Open access
PDF file
AAArianne Clare Agdamag
Arianne Clare Agdamag
JEJonathan B. Edmiston
Jonathan B. Edmiston
VCVictoria Charpentier
Victoria Charpentier
MCMohammed Chowdhury
Mohammed Chowdhury
MFMeg Fraser
Meg Fraser
TATamas Alexy
Tamas Alexy
Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) gained worldwide attention at the end of 2019 when it was identified to cause severe respiratory distress syndrome. While it primarily affects the respiratory system, we now have evidence that it affects multiple organ systems in the human body. Cardiac manifestations may include myocarditis, life threatening arrhythmias, acute coronary syndrome, systolic heart failure, and cardiogenic shock. Myocarditis is increasingly recognized as a complication of Coronavirus-19 (COVID-19) and may result from direct viral injury or from exaggerated host immune response. The diagnosis is established similar to other etiologies, and is based on detailed history, clinical exam, laboratory findings and non-invasive imaging studies. When available, cardiac MRI is the preferred imaging modality. Endomyocardial biopsy may be performed if the diagnosis remains uncertain. Current management is mainly supportive with the potential addition of interventions recommended for severe COVID-19 disease, such as remdesivir, steroids, and convalescent plasma. In the setting of cardiogenic shock and refractory, life-threatening arrhythmias that persist despite medical therapy, advanced mechanical circulatory support devices should be considered. Ultimately, early recognition and aggressive intervention are key factors in reducing morbidity and mortality. Our management strategy is expected to evolve further as we learn more about COVID-19 disease and the associated cardiac complications.

7 February 2022 in ASAIO Journal
Verified
Journal Article
Closed access
VMValmiki Maharaj
Valmiki Maharaj
TATamas Alexy
Tamas Alexy
AAArianne Clare Agdamag
Arianne Clare Agdamag
RKRajat Kalra
Rajat Kalra
BNBellony Nzemenoh
Bellony Nzemenoh
DYDemetris Yannopoulos
Demetris Yannopoulos
Respiratory failure caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is associated with mortality. Patients unresponsive to conventional therapy may benefit from temporary venovenous extracorporeal membrane oxygenation (VV-ECMO). We investigated clinical and echocardiographic characteristics, particularly, right ventricular dysfunction, with survival in patients with respiratory failure caused by SARS-CoV-2. We performed a single-center retrospective cohort study of patients requiring VV-ECMO for respiratory failure from COVID-19 infection between January 2020 and December 2020. Demographics, comorbidities, laboratory parameters, and echocardiographic features of left and right ventricular (LV/RV) function were compared between patients who survived and those who could not be weaned from VV-ECMO. In addition, we evaluated outcomes in a separate population managed with venoarterial extracorporeal membrane oxygenation (VA-ECMO). In total, 10/17 patients failed to wean from VV-ECMO and died in the hospital on average 41.5 ± 10.9 days post admission. Seven were decannulated (41%) and survived to hospital discharge. There were no significant differences in demographics, comorbidities, and laboratory parameters between groups. Moderate to severe RV dysfunction was significantly more in those who died (8/10, 80%) compared to survivors (0/7, 0%) (p = 0.002). Patients supported with VA-ECMO had superior survival with 5/9 patients (56%) decannulated and discharged. Moderate to severe RV dysfunction is associated with increased mortality in patients with respiratory failure requiring VV-ECMO for COVID-19.

10 January 2024 in Catheterization and Cardiovascular Interventions
Verified
Journal Article
Open access
RKRajat Kalra
Rajat Kalra
TATamas Alexy
Tamas Alexy
JBJason A. Bartos
Jason A. Bartos
APAnthony R. Prisco
Anthony R. Prisco
MKMarinos Kosmopoulos
Marinos Kosmopoulos
DYDemetris Yannopoulos
Demetris Yannopoulos
Background: There is considerable debate about the hemodynamic effects of veno‐arterial extracorporeal membrane oxygenation (VA‐ECMO).Aims: To evaluate the changes in left ventricular (LV) function, volumes, and work in patients treated with VA‐ECMO using invasive LV catheterization and three‐dimensional echocardiographic volumes.Methods: Patients on VA‐ECMO underwent invasive hemodynamic evaluation due to concerns regarding candidacy for decannulation. Hemodynamic parameters were reported as means±standard deviations or medians (interquartile ranges) after evaluating for normality. Paired comparisons were done to evaluate hemodynamics at the baseline (highest) and lowest tolerated levels of VA‐ECMO support.Results: Twenty patients aged 52.3 ± 15.8 years were included. All patients received VA‐ECMO for refractory cardiogenic shock (5/20 SCAI stage D, 15/20 SCAI stage E). At 3.0 (2.0, 4.0) days after VA‐ECMO cannulation, the baseline LV ejection fraction was 20% (15%, 27%). The baseline and lowest VA‐ECMO flows were 4.0 ± 0.6 and 1.5 ± 0.6 L/min, respectively. Compared to the lowest flow, full VA‐ECMO support reduced LV end‐diastolic volume [109 ± 81 versus 134 ± 93 mL, p = 0.001], LV end‐diastolic pressure (14 ± 9 vs. 19 ± 9 mmHg, p < 0.001), LV stroke work (1858 ± 1413 vs. 2550 ± 1486 mL*mmHg, p = 0.002), and LV pressure‐volume area (PVA) (4507 ± 1910 vs. 5193 ± 2388, p = 0.03) respectively. Mean arterial pressure was stable at the highest and lowest flows (80 ± 16 vs. 75 ± 14, respectively; p = 0.08) but arterial elastance was higher at the highest VA‐ECMO flow (4.9 ± 2.2 vs lowest flow 2.7 ± 1.6; p < 0.001).Conclusions: High flow VA‐ECMO support significantly reduced LV end‐diastolic pressure, end‐diastolic volume, stroke work, and PVA compared to minimal support. The Ea was higher and MAP was stable or minimally elevated on high flow.