Key result
Higher perfusion pressure increases myocardial stiffness across all strains, driven by vascular mechanical changes.
Why the study?
The effect of perfusion pressure on diastolic muscle properties and stress-strain relations in isolated rat papillary muscle was investigated to understand mechanical behavior changes.
Increased muscle stiffness at higher perfusion pressures in isolated rat papillary muscles is likely driven by pressure-dependent changes in the vascular compartment rather than edema.
May confound ex vivo stiffness measurements; extends vascular-myocardial models but leaves in vivo relevance open.
The effect of perfusion on diastolic muscle properties was investigated in six isolated right ventricular papillary muscles from rat hearts perfused with a crystalloid solution via the septal artery. Stress-strain relations were obtained at different perfusion pressures. Increased perfusion pressure caused an increase of stress at large strains but a decrease of stress at low strains. Thus stress-free strain increased with increasing perfusion pressure. Stress-strain relations of a given muscle at different perfusion pressures (range 12-122 cmH2O) intersected at a single "crossover" strain. Muscle stiffness, defined as the slope of the stress-strain relation, increased at all strains. Muscle diameter measurements indicated that the observed changes of the stress-strain relation occurred in association with vascular filling rather than with formation of edema. To explain the findings, the papillary muscle was modeled by two parallel compartments: muscle cells (together with the extracellular matrix) and vasculature. Perfusion was assumed to have an effect on the axial vascular properties but not on muscle cells. Combination of the stress-strain data of the muscle compartment and the vascular compartment (taken from literature) predicted stress-strain relations similar to those obtained in our perfused papillary muscles. We conclude that increased muscle stiffness at increased perfusion pressure is mainly caused by pressure-dependent changes in mechanical behavior of the vascular compartment.
No takes yet. Share an insight, caveat, or question.
Allaart et al. (1995) studied this question. Increased perfusion pressure vs. Different perfusion pressures was evaluated on Diastolic muscle properties (stress-strain relations). Increased perfusion pressure increased muscle stiffness at all strains, mainly caused by pressure-dependent changes in the mechanical behavior of the vascular compartment.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: