Hemodynamic correlates of exercise function in patients with primary pulmonary hypertension.

The purpose of this investigation was to study the hemodynamic correlates of exercise function in patients with primary pulmonary hypertension and to further define the role of exercise testing in the evaluation of these individuals. Data from the progressive exercise tests and subsequent cardiac catheterization in 16 consecutive patients, aged 16.9 +/- 10.4 years (range 6 to 35), with primary pulmonary hypertension were prospectively collected and analyzed. Exercise capacity averaged 40 +/- 36% (range 0 to 117%) of that predicted for age, height and gender. Statistically significant correlations existed between exercise capacity and 10 invasively measured hemodynamic variables. Mean right atrial pressure, a variable previously noted to be one of the best predictors of survival in patients with primary pulmonary hypertension, correlated best with exercise capacity (r = -0.83, p less than 0.0001). Exercise capacity greater than 75% of the predicted value identified the two patients who had a positive response to acute pulmonary vasodilator drug testing. Poor exercise capacity (less than 10% of the predicted value) identified the three patients who died during or soon after cardiac catheterization. The ability of exercise testing to identify patients at high risk for cardiac catheterization was superior to that of other noninvasive variables. Results of exercise testing may help guide decisions regarding the optimal timing of heart-lung or single lung transplantation.