Systemic arterial compliance

SAC (SVi / pulse pressure) · Derived: SAC = SVi / (SBP − DBP)

Normal range & thresholds

≥0.6 mL/m²/mmHg normal. <0.6 indicates a stiff arterial tree and independently predicted events in aortic stenosis ^[113].

Pathophysiology

Compliance is the pulsatile component of afterload: a stiff aorta returns reflected waves in systole and raises pulse pressure, adding load the ventricle must meet late in ejection. It falls with age, hypertension and diabetes, and contributes to the HFpEF phenotype ^[161].

Raised by

• Youth, athletic conditioning, vasodilation

Lowered by

• Ageing, hypertension, diabetes, CKD, AS, HFpEF

Technique & pitfalls

• Brachial pulse pressure is a proxy for central pressure.

Pseudo-change & artefact

• Pulse-pressure amplification; SVi error.

Treatment thresholds

No direct threshold; supports aggressive BP control per the 2024 ESC hypertension guideline ^[26].

Next step

• Combine with Ea and Zva to define whether load is resistive, pulsatile or valvular.

Drugs

Long-term BP control and RAAS blockade improve it modestly.

Reversibility

Largely structural; slow partial improvement.