PURPOSE: Pulmonary hypertension (PH) is a common complication in COPD. PH is generally mild to moderate in COPD and becomes more manifest during exercise. Sildenafil is a selective pulmonary vasodilator. We aimed to investigate the acute effects of sildenafil on hemodynamics both at rest and during exercise in COPD patients, and to determine whether the hemodynamic response in COPD patients without PH differs from COPD patients with PH.
METHODS: 12 COPD patients (GOLD stages II-IV) with suspected PH underwent right heart catheterization: mean pulmonary artery pressure (mPpa) and cardiac output (Fick method) were assessed. The exercise protocol consisted of 3 minutes of cycling in supine position at 40% of maximal workload. Resting and exercise measurements were repeated 45 minutes after oral intake of 50 mg sildenafil. PH was defined as > 25 mmHg at rest or > 30 mmHg during exercise.
RESULTS: Results are summarized in Table 1. PH was found in 6 out of 12 COPD patients. Exercise induced a significant increase in mPpa in both groups. In the whole group, exercise mPpa was significantly lower with sildenafil (35 ± 17 vs 31 ± 21 mmHg, respectively). In contrast to COPD-PH, in COPD-nonPH patients mPpa was reduced both at rest and during exercise after sildenafil (p = 0.06 and p < 0.05, respectively). Stroke volume (SV) was higher at rest and during exercise in COPD-nonPH patients. SV significantly increased on exercise in the whole group. In the whole group, resting mPpa was inversely related to resting and exercise SV (r = −0.67 and r = −0.72, p < 0.02, resepectively).
CONCLUSION: Exercise induces a rise in mPpa in COPD patients with and without associated PH. Sildenafil is effective in reducing afterload both at rest and during exercise in COPD patients without associated PH.
CLINICAL IMPLICATIONS: These data suggest that during daily activities some COPD patients may benefit from agents that cause pulmonary vasodilation.
DISCLOSURE: Sebastiaan Holverda, None.