Clinical Disease

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Must-have

Severe Aortic Stenosis — Preload, Afterload & Hemodynamic Management

Fixed LV outflow obstruction demands preload preservation, avoidance of afterload reduction, and tight heart-rate control

Severe aortic stenosis creates a fixed LV outflow obstruction where the hypertrophied, non-compliant ventricle is preload-dependent and intolerant of afterload reduction, tachycardia, and loss of sinus rhythm.

If you forget

Headline: Preload-DEPENDENT, afterload-INTOLERANT, rate-DISTRESSED

Board trap

Severe AS patient becomes hypotensive after induction — give phenylephrine (α-agonist) to restore SVR. AVOID ephedrine: β1 inotropy increases LV work against a fixed orifice and worsens outflow obstruction.

Key numbers

Severe AS: Vmax ≥4 m/s, mean ΔP ≥40 mm Hg, AVA ≤1.0 cm² (ACC/AHA Stage D1)
Very severe AS: Vmax ≥5 m/s or mean ΔP ≥60 mm Hg
AVAi ≤0.6 cm²/m² confirms severe (Stage D1)
Low flow: SVi <35 mL/m²; high flow: SVi >58 mL/m² (ASE/EACVI)
Stroke work loss % = (ΔP/(ΔP+SBP)) × 100 — % of LV work wasted at valve
Goal: HR 60-80 bpm, SBP within 20% of baseline

Reviewed Sep 24, 2026 for clinical accuracy by BoardsBridge Editorial Process

Uri Rozen, MD — Licensed Physician, Israel

Source guidelines: ACC AHA Valvular Heart Disease 2020 · ACC AHA Valvular Heart Disease 2020 · ASE EACVI Aortic Stenosis 2017

Re-review cadence: 12 months from reviewed date.

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Card ID: preload-afterload-severe-as · Path: aba.physiology.cardiac.preload-afterload-severe-as