Hemodynamic and metabolic characteristics associated with development of a right ventricular outflow tract pressure gradient during upright exercise

Figures

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  Fig 1. Relationships between supine and upright resting right ventricular outflow tract (RVOT) gradient and peak exercise RVOT gradient. Scatterplots of peak RVOT pressure gradient (i.e., RVSP-PASP) versus supine resting RVOT gradient (Panel A), upright resting RVOT gradient (Panel B), and the change in RVOT pressure gradient between from supine to upright positions at rest (Panel C). In the small subset of cases where resting RVSP-PASP was negative, the gradient was set to 0 mmHg. PASP—pulmonary artery systolic pressure; RVSP—right ventricular systolic pressure.

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  Fig 2. Association between selected exercise hemodynamic variables and right ventricular outflow tract (RVOT) systolic pressure gradient at peak exercise. Scatterplots showing the relationship of various peak exercise hemodynamic variables with RVOT systolic pressure gradient at peak exercise. The best-fit linear regression line is plotted with 95% confidence intervals. Panel A—Peak cardiac index versus peak RVOT gradient; Panel B—Peak RAP versus peak RVOT gradient; Panel C—Peak stroke volume versus peak RVOT gradient; Panel D—Peak heart rate versus peak RVOT gradient. RAP—right atrial pressure; RVOT—right ventricular outflow tract.

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  Fig 3. Relationships between peak right ventricular systolic and pulmonary artery systolic and mean pressures at peak exercise. (Panel A) Scatterplot showing the close correspondence of invasively measured peak exercise systolic pulmonary artery (PA) pressure and mean PA pressure. (Panel B) Scatterplot of invasively measured peak exercise systolic right ventricular (RV) pressure against peak exercise systolic PA pressure. Peak RV systolic pressure is systematically higher than peak PA systolic pressure. Also, the correlation between RV and PA systolic pressures is less robust than would be expected. (Panel C) As a result of the systematic but variable RV-to-PA systolic pressure gradient, the relationship between peak systolic RV pressure and peak mean PA pressure is only moderately strong. For all panels, the solid black line represents the best-fit regression line with dotted lines representing 95% prediction limits. The dashed red line in panel B signifies identity (x = y). PA- pulmonary artery; RV- right ventricle.

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  Fig 4. Receiver operating characteristic curve analysis of resting and peak exercise right heart pressures to identify peak exercise mean pulmonary artery pressure >30 mmHg. Peak exercise PA systolic pressure is able dependably to identify patients with abnormally high mean PA pressure at peak exercise (AUC 0.97, blue dotted-dashed line). Peak exercise RVSP is less well able to discriminate between normal and elevated exercise mean PA pressure (AUC 0.82, red solid line). Resting supine right heart catheterization RV systolic pressure (AUC 0.83, brown dashed double-dotted line) and PA systolic pressures (AUC 0.86, green dashed line) each provided similar or slightly better discrimination between normal and elevated exercise PA pressure. PA—pulmonary artery; PASP—pulmonary artery systolic pressure; RV—right ventricle; RVSP—right ventricle systolic pressure.