Publications by authors named "M D Lyhne"

The unprimed right ventricle is exquisitely sensitive to acute elevations in afterload. High pulmonary vascular tone incurred with acute pulmonary embolism has the potential to induce obstructive shock and circulatory collapse. While emergent pulmonary reperfusion is essential in severe circumstances, an important subset of pulmonary embolism patients may exhibit a less extreme presentation posing a management dilemma.

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Current methods for quantifying perfusion from computed tomography pulmonary angiography (CTPA) often rely on semi-quantitative scoring systems and requires an experienced evaluator. Few studies report on absolute quantitative variables derived from the images, and the methods are varied with mixed results. Dual-energy CTPA (DE-CTPA) enables automatic quantification of lung and lobar perfusion with minimal user interaction by utilizing machine learning based software.

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Background: Acute pulmonary embolism (PE) mortality is linked to abrupt rises in pulmonary artery (PA) pressure due to mechanical obstruction and pulmonary vasoconstriction, leading to right ventricular (RV) dilation, increased RV wall tension and oxygen demand, but compromised right coronary artery oxygen supply. Oxygen is a known pulmonary vasodilator, and in preclinical animal models of PE, supplemental oxygen reduces PA pressures and improves RV function. However, the mechanisms driving these interactions, especially in humans, remain poorly understood.

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Article Synopsis
  • Acute pulmonary embolism (PE) negatively impacts right ventricular function, which can be evaluated using the TAPSE/PASP ratio to predict patient outcomes.
  • A study analyzed data from over 4,400 patients with PE and found lower TAPSE/PASP ratios correlated with higher 30-day mortality rates, especially in intermediate-risk patients.
  • The TAPSE/PASP ratio is suggested to be a valuable tool for enhancing clinical decision-making and identifying patients at greater risk of mortality, beyond existing risk assessment methods.
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Article Synopsis
  • Chronic thromboembolic pulmonary hypertension (CTEPH) causes right ventricular dysfunction due to increased pressure in the lungs, and this study focuses on the relationship between RV to pulmonary artery coupling and invasive heart measurements.
  • A cohort of 139 CTEPH patients was studied, showing a significant correlation between the echocardiographic TAPSE/PASP ratio and pulmonary vascular resistance, with improvements in this ratio following treatments like BPA and PEA.
  • The findings suggest that the TAPSE/PASP ratio can be a useful tool for monitoring treatment outcomes in CTEPH patients, though further research is needed to determine its prognostic value and influence on treatment decisions.
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