by Michelle Rizzo
Last Updated: 2009-11-26 12:00:22 -0400 (Reuters Health)
Pulmonary hypertension may cause functional limitations and increase mortality in patients with obstructive sleep apnea syndrome (OSA), say researchers from the Cleveland Clinic in Ohio. Though generally mild to moderate, severe pulmonary hypertension may occur in this population.
"Greater attention has to be paid to pulmonary hypertension as a morbidity in patients with OSA since it can impact functional capacity and survival," lead author Dr. Omar A. Minai told Reuters Health. "Patients with OSA who have factors indicative of increased risk of pulmonary hypertension should be screened for pulmonary hypertension."
The researchers analyzed data from 83 OSA patients undergoing pulmonary artery catheterization to examine the frequency and impact of pulmonary hypertension. They assessed the predictors of pulmonary hypertension in these patients, and sought to determine whether non-invasive measures are helpful in making the diagnosis of pulmonary hypertension. The findings are published in the November issue of the American Journal of Cardiology.
Of the 83 patients, 58 (70%) had pulmonary hypertension and 25 (30%) did not. Eighteen patients had a pulmonary capillary wedge pressure of < 15 mm Hg. There were no significant differences between patients with and without pulmonary hypertension in terms of age or apnea-hypopnea index.
The strongest correlates of pulmonary function on multivariate analysis were female gender, age < 49 years, and right ventricular systolic pressure > 30 mm Hg.
Overall, 27 patients (33%) had severe pulmonary hypertension, defined as a mean pulmonary arterial pressure of > 40 mm Hg. Patients with severe pulmonary hypertension had more nocturnal desaturation, worse hemodynamics, and greater mortality than those with mild or moderate pulmonary hypertension or no pulmonary hypertension.
The 6-minute walk distance was lower among patients with pulmonary hypertension compared to those without it (285.5 m versus 343 m). At 1, 4, and 8 years, the survival rates were 100%, 90%, and 76% in patients without pulmonary hypertension and 93%, 75%, and 43% in those with pulmonary hypertension.
"Since pulmonary hypertension may occur from a variety of potential etiologic factors, once pulmonary hypertension is found, its potential etiology should be determined and treated," Dr. Minai told Reuters Health.
"The next step involves 1) translational research into etiologic mechanisms, 2) further delineation of true functional limitation imposed by pulmonary hypertension, 3) evaluating our prediction score for pulmonary hypertension in a different dataset of patients with OSA, 4) designing studies on treatment options for pulmonary hypertension in patients with OSA and to determine if these treatments impact on functional limitation and/or survival," the researcher explained.
Am J Cardiol 2009;104:1300-1306.