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Increased aortic compliance maintains left ventricular performance at lower energetic cost
P Kolh1, V D'Orio, B Lambermont
1Haemodynamic Research Center, University of Liège, Belgium. philippe.kolh@chu.ulg.ac.be
Summary
Increasing aortic compliance reduces the heart's workload, decreasing the energetic cost of cardiac ejection without affecting left ventricular contractility. This finding is crucial for selecting artificial aortic prostheses.
Area of Science:
- Cardiovascular Physiology
- Biomedical Engineering
Background:
- The mechanical properties of the aorta significantly influence left ventricular (LV) function and energetic efficiency.
- Understanding how changes in aortic compliance affect cardiac performance is essential for managing cardiovascular diseases and developing medical devices.
Purpose of the Study:
- To investigate the impact of acutely increased aortic compliance on left ventricular contractility and the energetic cost of cardiac ejection.
- To assess changes in myocardial oxygen consumption and LV systolic function under augmented aortic compliance.
Main Methods:
- Acute increases in ascending aortic compliance were induced in anesthetized pigs by adding a parallel volume chamber.
- Systemic vascular parameters were estimated using a four-element windkessel model, including characteristic impedance, peripheral resistance, and arterial elastance.
- Left ventricular systolic function was evaluated via end-systolic pressure-volume relationship (end-systolic elastance), stroke work, and pressure-volume area (PVA) as a measure of myocardial oxygen consumption.
Main Results:
- A significant increase in aortic compliance was achieved, while characteristic impedance, peripheral resistance, and arterial elastance remained unchanged.
- Stroke work and pressure-volume area (myocardial oxygen consumption) were significantly reduced at matched end-diastolic volumes.
- Left ventricular contractility, assessed by end-systolic elastance, ejection fraction, and stroke volume, remained statistically unchanged.
Conclusions:
- Acute augmentation of aortic compliance reduces the energetic cost of cardiac ejection without altering left ventricular contractility.
- These findings have clinical implications for the selection of artificial prostheses for ascending aortic replacement, potentially guiding the design of devices that optimize cardiac efficiency.