The effect of a proximal coronary artery stenosis on transmural myocardial blood flow during exercise was studied in nine dogs with electromagnetic flowmeter probes and hydraulic occluders on the left circumflex coronary artery. Regional myocardial blood flow at rest and during treadmill exercise was estimated with radioactive microspheres 7-10 mum in diameter. Exercise studies were performed during unrestricted coronary artery inflow (control exercise) and during partial inflation of the occluder to a level which did not reduce flow at rest but which limited the increase in flow during exercise to 66 +/- 6% (mild restriction) or 44 +/- 3% (severe restriction) of the value during control exercise. Mean myocardial blood flow at rest was 0.94 +/- 0.06 ml/min per g of myocardium and increased to 2.45 +/- 0.15 ml/min per g during control exercise, with uniform distribution across the wall of the left ventricle. Flow to the subepicardial myocardium was significantly greater during exercise in the presence of a mild restriction than during control exercise, whereas flow to deeper layers of myocardium was progressively decreased below the control level. A similar pattern of redistribution of flow occurred during exercise in the presence of a severe restriction, but flow to all transmural layers was below that during mild restriction, resulting in more marked subendocardial underperfusion. Thus, exercise in the presence of stenosis resulted in transmural redistribution of myocardial blood flow with subendocardial underperfusion in proportion to the degree of restriction of coronary artery inflow.
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http://dx.doi.org/10.1161/01.res.38.2.60 | DOI Listing |
ACS Nano
January 2025
Jiangsu Key Laboratory for Biomaterials and Devices, School of Biomedical Sciences and Medical Engineering, Southeast University, Nanjing 210096, P. R. China.
The blood flow, when restored clinically following a myocardial infarction (MI), disrupts the physiological and metabolic equilibrium of the ischemic myocardial area, resulting in secondary damage termed myocardial ischemia-reperfusion injury (MIRI). Reactive oxygen species (ROS) generation and inflammatory reactions stand as primary culprits behind MIRI. Current strategies focusing on ROS-scavenging and anti-inflammatory actions have limited remission of MIRI.
View Article and Find Full Text PDFFront Neurol
January 2025
Department of Neurosurgical Intensive Care Unit, Henan Provincial People's Hospital, Zhengzhou, China.
Background: The effect of targeted temperature management (TTM) combined with decompressive craniectomy (DC) on poor-grade aneurysmal subarachnoid hemorrhage (aSAH) has not been previously addressed in the literature. This study aims to investigate the therapeutic outcomes of the combination of TTM and DC in patients with poor-grade aSAH.
Methods: This study represents a secondary analysis of the Multicenter Clinical Research on Targeted Temperature Management of Poor-grade Aneurysmal Subarachnoid Hemorrhage (High-Quality TTM for PaSAH), a multicenter prospective study conducted in China.
Front Immunol
January 2025
Department of Cardiovascular Medicine, Mayo Clinic, Jacksonville, FL, United States.
Introduction: Extracellular vesicles (EVs) can potently inhibit inflammation yet there is a lack of understanding about the impact of donor characteristics on the efficacy of EVs. The goal of this study was to determine whether the sex and age of donor platelet-derived EVs (PEV) affected their ability to inhibit viral myocarditis.
Methods: PEV, isolated from men and women of all ages, was compared to PEV obtained from women under 50 years of age, which we termed premenopausal PEV (pmPEV).
Cureus
December 2024
Internal Medicine, Combined Military Hospital, Quetta, PAK.
Shock is a state of inadequate perfusion that affects vital organs. Cardiogenic shock (CS) predisposes patients to various arrhythmias. The adverse effect depends on intervention and pharmacogenomics.
View Article and Find Full Text PDFEur Heart J Case Rep
January 2025
Second Department of Cardiology, University of Ioannina Medical School, University Campus, Stavros Niarchos Avenue, Ioannina 45 500, Greece.
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