Pulmonary Artery Wedge Pressure Relative to Exercise Work Rate in Older Men and Women

Purpose: An augmented pulmonary artery wedge pressure (PAWP) response may explain exercise intolerance in some humans. However, routine use of exercise hemodynamic testing is limited by a lack of data from normal older men and women. Our objective was to evaluate the exercise PAWP response and the potential for sexual dimorphism in healthy, nondyspneic older adults. Methods: Thirty-six healthy volunteers (18 men [54 +/- 7 yr] and 18 women [58 +/- 6 yr]) were studied at rest (control) and during two stages of semi-upright cycle ergometry, at heart rates of 100 bpm(light exercise) and 120 bpm(moderate exercise). Right heart catheterization was performed to measure pulmonary pressures. The PAWP response to exercise was assessed in context of exercise work rate and body size. Results: At control, PAWP was similar between men and women. Work rates were significantly smaller in women at comparable HR (P < 0.001). PAWP increased similarly at light exercise, with no further increase at moderate exercise. When indexed to work rate alone or work rate adjusted to body weight and height, the PAWP response at light and moderate exercise was significantly elevated in women compared with men (P < 0.05 condition-sex interaction). The change in PAWP relative to the increase in cardiac output did not exceed 2 mm Hg.L-1 .min(-1) in any volunteer at moderate exercise. Conclusions: The similar rise in the PAWP response to submaximal exercise occurs despite lower work rate in healthy older women compared with men, even when adjusted for smaller body size. It is important to consider sex in the development of normal reference ranges for exercise hemodynamic testing.