How does aging affect arterial compliance and what PV-loop consequence might result?

How does aging affect arterial compliance and what PV-loop consequence might result?

• A. Aging reduces arterial stiffness, decreasing afterload; PV loop shows lower systolic pressures.
• B. Aging reduces arterial compliance (stiffer arteries), increasing afterload for a given SV; PV loop shows higher systolic pressures and smaller SV.
• C. Aging improves arterial compliance; loop widens.
• D. Aging has no effect on PV loop.

Answer: (B)

Aging makes arteries stiffer, reducing their ability to stretch with pressure. That drop in arterial compliance raises the afterload the heart has to pump against for any given stroke volume. In a pressure–volume loop, higher afterload means the ventricle must generate more pressure to eject blood, so systolic pressure is increased. At the same time, the stiffer arterial system makes ejection less complete, so the stroke volume falls. On the PV loop this shows up as a higher peak pressure (taller loop) with a smaller width (narrower loop) due to the reduced stroke volume. So the best description is that aging reduces arterial compliance (arteries become stiffer), increasing afterload for a given stroke volume; the PV loop shows higher systolic pressures and smaller stroke volume. The other statements conflict with the idea of stiffer arteries and the associated PV-loop changes.

Aging makes arteries stiffer, reducing their ability to stretch with pressure. That drop in arterial compliance raises the afterload the heart has to pump against for any given stroke volume. In a pressure–volume loop, higher afterload means the ventricle must generate more pressure to eject blood, so systolic pressure is increased. At the same time, the stiffer arterial system makes ejection less complete, so the stroke volume falls. On the PV loop this shows up as a higher peak pressure (taller loop) with a smaller width (narrower loop) due to the reduced stroke volume.

So the best description is that aging reduces arterial compliance (arteries become stiffer), increasing afterload for a given stroke volume; the PV loop shows higher systolic pressures and smaller stroke volume. The other statements conflict with the idea of stiffer arteries and the associated PV-loop changes.