Right Ventricular Contractility is Preserved in Patients with Cystic Fibrosis and Pulmonary Artery Hypertension

Abstract

A combined hemodynamic and radionuclide approach was used to evaluate right ventricular contractility in 16 adolescent and adult patients with cystic fibrosis (CF). Nine patients had normal resting pulmonary artery pressure, and seven had resting pulmonary artery hypertension (PH). Right ventricular ejection fraction (RVEF) was observed by radionuclide angiocardiography, and stroke volume index (SVI) by thermodilution techniques. By combination of these measures right ventricular enddiastolic and end-systolic volumes were derived. RVEF was normal in CF patients without PH (58.9 ± 7.2%) but was reduced in those with PH (45.4 ± 2.3%). There was a strong inverse linear correlation between RVEF and afterload, as assessed by mean pulmonary artery pressure (r = -0.76), indicating RVEF being afterload-dependent. Right ventricular contractility, however, as assessed by right ventricular end-systolic pressure-volume relations was even higher in CF patients with PH, indicating preserved or even increased contractility in the face of an increased afterload stress. The acceleration time, evaluated by pulsed Doppler echocardiography, was normal in CF patients without PH (117.3 ± 5.5 msec) and significantly reduced in those with PH (85.1 ± 6.4 msec). Both RVEF and AT were efficient in estimating pulmonary artery pressure in these patients.

Key Words:

• Cystic fibrosis
• Doppler echocardiography
• pulmonary artery hypertension
• right ventricular function