Hemodynamic effects of cycle ergometry and low-intensity handgrip in patients with pulmonary hypertension

Abstract

In pulmonary hypertension (PH), the hemodynamic response to exercise during right heart catheterization (RHC) can unmask latent left heart disease, is associated with prognosis, and can facilitate the understanding of patient's symptoms and the pathophysiology of heart failure. As cycle ergometry isn't widely available, we compared the hemodynamic effects of ergometry with isometric handgrip exercise. This prospective study included 50 consecutive patients (mean age 68 ± 12 years, 54% female) with suspected or confirmed PH who underwent RHC. In a semi-recumbent position, hemodynamic parameters were recorded at rest and during both randomized exercise modalities, each sustained for a mean of 6-7 minutes and separated by another resting phase. Cardiac output was determined by thermodilution. Handgrip pressure was set to 20% of maximal force, while cycle ergometry was performed at a constant work rate between 10 to 50 watts. Both modalities induced significant changes of hemodynamic parameters compared to baseline, which were considerably smaller during handgrip. Mean pulmonary arterial pressure increased by 14 mmHg under cycling vs. 4 mmHg under handgrip (p<0.001), pulmonary artery wedge pressure (PAWP) by 5 mmHg vs. 2 mmHg (p<0.001), and cardiac output by 1.5 l/min vs. 0.2 l/min (p<0.001). In patients with PAWP ≤ 15 mmHg at rest, an increase > 25 mmHg occurred in two cases during cycle ergometry but in none during handgrip exercise. Compared with cycle ergometry, low-intensity isometric handgrip exercise at 20% of maximal force produces significantly smaller alterations in hemodynamic parameters measured by RHC in PH patients, and thus is not suitable as an adequate substitute for the established exercise modality.