Dobutamine and Pulmonary Artery Function Studied

In patients with heart failure with preserved ejection fraction (HFpEF) pulmonary artery hypertension and right ventricular dysfunction are common and associated with mortality.

In an effort to find ways to improve pulmonary vascular tone, Seok-Jae Hwang, MD, PhD and colleagues at the Mayo Clinic’s Division of Cardiovascular Diseases, Department of Medicine, in Rochester, Minn. assessed the differences in hemodynamics in a group of 39 HFpEF patients and 18 controls.

The subjects in the prospective study underwent comprehensive invasive and non-invasive assessment. Researchers used micromanometer catheters with expired gas analysis both when patients' hearts were at rest and when they got infusions of dobutamine. The drug stimulates the Beta 1 receptors of the heart.

Compared to the controls, the HFpEF patients tended to display impaired right ventricular contractility and prolonged relaxation at rest with lower pulmonary artery compliance and increased pulmonary resistance.

Dobutamine enhanced right ventricular contractility and relaxation similarly in both groups, the HFpEF patients showed greater acute improvements in pulmonary artery vascular function, with enhanced reduction in pulmonary artery resistance and greater increase I pulmonary artery compliance.

Hwang’s conclusion is that “pulmonary vascular tone is more favorably responsive to acute beta-adrenergic stimulation in HFpEf patients than controls.” But more research is needed to better understand the autonomic regulation of pulmonary vascular function in these patients.

The study will be presented Saturday March 14 in a poster session at the American College of Cardiology meeting in San Diego, CA.