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. 2021 Mar 11;8(1):G19–G59. doi: 10.1530/ERP-20-0035

Figure 17.

Figure 17

Worked example of the projected EOA methodology: A patient with severe LV impairment was noted to have calcified restricted aortic valve (A). The LVOTd is 2.2 cm (B). The LVOT cross-sectional area is 3.8 cm2. Optimal CW and PW recordings were obtained from the 5-chamber window (C and D). AV Vmax 2.4 m/s; mean gradient 16 mmHg; AV VTI 50 cm (E); LVOT VTI 9 cm. AVA at rest calculated using the continuity equation: AVArest = LVOT VTI ÷ AV VTI x LVOT CSA = 9 cm ÷ 50 cm × 3.8 cm2 = 0.68 cm2. Flow at rest (Qrest) is calculated from the stroke volume and the ejection time (F): Qrest = stroke volume ÷ ejection time = 9 cm × 3.8 cm2 ÷ 0.36 s = 95 mL/s. At maximal stress, CW Doppler was obtained (G): AV Vmax 3.2 m/s; mean gradient 28 mmHg; AV VTI 61 cm. PW Doppler at peak stress (H): LVOT VTI 16 cm; ejection time was 0.33 ms. The LVOTd is assumed to remain unchanged with stress. AVApeak = LVOT VTI ÷ AV VTI × LVOT CSA = 16 cm ÷ 61 cm × 3.8 cm2 = 1.0 cm2. Qpeak = stroke volume ÷ ejection time = 16 cm x 3.8 cm2 ÷ 0.33 s = 184 mL/s. Note that the stroke volume has increased by >20% and therefore the patient has contractile reserve. The mean gradient has only increased to 28 mmHg, and therefore this patient does not fulfil the criteria for ‘true-severe AS’. Equally, the patient has not fulfilled the usual criteria for ‘pseudo-severe’ AS, which mandates an AVA ≥1.2 cm2 at peak stress. The projected-EOA calculates the AVA at a ‘normal’ transvalvular flow rate of 250 mL/s: Projected EOA = AVArest + ((AVApeak – AVArest) ÷ (Qpeak – Qrest) × (250 – Qrest)). Projected EOA = 0.68 + ((1.0 – 0.68) ÷ (184 – 95) × (250 – 95)) > 1.2 cm2. An EOA-Proj > 1.2 cm2 is consistent with ‘pseudo-severe AS’. This patient should therefore be treated medically.