Integrating Cardiopulmonary Exercise Testing in the Assessment of Aortic Stenosis: A Comprehensive Review

Figures

• 

  Figure 1. Normal nine-panel plot CPET results of a 30-yr-old female weighing 55 kg. V.E BTPS, minute ventilation at body temperature, ambient pressure saturated with water vapour (L min−1); time (min); HR, heart rate (beats min−1); V.O2/HR, oxygen consumption divided by HR ‘oxygen pulse’ (mL beat−1); VO2, oxygen consumption (L min−1); V.CO2, carbon dioxide production (L min−1); work (W); V.E/V.O2, minute ventilation divided by oxygen consumption (no units); V.E/V.CO2, minute ventilation divided by carbon dioxide production (no units); Vt BTPS, tidal volume at body temperature, ambient pressure saturated with water vapour (L min−1); RER, respiratory exchange ratio V.CO2/V.O2 (no units); PETO2, end-tidal oxygen tension (mm Hg); PETCO2, end-tidal carbon dioxide tension (mm Hg); SaO2, refers to arterial oxygen saturation, however in this CPET the peripheral oxygen saturation (SpO2) was measured by pulse oximetry and used as a surrogate(%); Exer, unloaded exercise; Work, loaded exercise; Rec, recovery; The dark red box in panel 2 represents the 80–100% range of maximal predicted HR. The horizontal dashed line in panels 3 and the vertical dashed line in panel 5 represent predicted 80% of maximal…

• 

  Figure 2. Panels 5 and 6 for determining anaerobic threshold (AT) using the ventilatory equivalents and V-slope methods. For abbreviations, see legend to Figure 1. (A) In panel 6, the red filled circles denote the ventilatory equivalents for V.CO2 (V.E/V.CO2) and the black open squares denote the ventilatory equivalents for V.O2 (V.E/V.O2). The red arrow indicates where the two slopes crossover and diverge and the anaerobic threshold (AT) can be determined using the ventilatory equivalents. The black dashed vertical lines correspond to Exer, unloaded exercise; Work, loaded exercise; and Rec, recovery; (B) In panel 5 the black open squares denote the V.CO2/V.O2 slope. The 2 purple dashed lines have been manually added to reflect the slope of the curve and identify the point of inflection where there is a sudden increase in gradient demonstrating a shift from aerobic to anaerobic metabolism known as the AT. This method for determining AT is referred to as the V-slope method. The black closed diamonds denote the HR which increases throughout the test. (C) Panel 9 can be used to verify the AT identified from panel 5 by using the end-tidal pressure method. The red filled circles show the end…

• 

  Figure 3. A proposed algorithm which integrates CPET data into the assessment of asymptomatic patients with significant AS. Data supporting this table are derived from studies shown in Table 3.