Page 15 - Assessing right ventricular function and the pulmonary circulation in pulmonary hypertension Onno Anthonius Spruijt

overdrive. This ventilatory inefficiency (increased VE/VCO2 slope) is a hallmark of PH and may contribute to the sensation of dyspnea [23, 26, 29, 32] (Figure 3). Finally, diaphragm weakness can lead to a further increase of breathlessness during exercise [33].
Recently, invasive assessment of hemodynamics during exercise has received interest in PH studies. Such exercise protocols are completed with pulmonary artery and radial artery catheters in situ, giving a more complete hemodynamic and ventilatory evaluation during exercise [34] (figure 4).
Figure 4: Invasive cardiopulmonary exercise test.
The ability to increase CO during exercise depends on the fitness of an individual and the slope of the mPAP-CO relationship which is steeper in older subjects [35]. It has been suggested that a mPAP of 30mmHg at a CO <10L/min and a mPAP-CO slope >3mmHg per L/min represent the upper limits of normal. A slope of >2,5mmHg per L/min is probably abnormal in younger individuals [8, 35-38]. Such criteria for the upper limits of normal for the mPAP-CO relation are not yet officially endorsed in the PH guidelines because they require external validation.
Chapter 1
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