Determinants of exercise-induced pulmonary hypertension in patients with normal left ventricular ejection fraction

¹ Yonsei University College of Medicine, Korea, Republic of

^* To whom correspondence should be addressed. E-mail: jwha{at}yuhs.ac.

Accepted 24 June 2008

	Abstract

Background: Pulmonary hypertension (PH) can occur during exercise and has an adverse effect on functional status, exercise tolerance, and prognosis. However, the role of cardiac function abnormalities on exercise-induced PH in patients with normal left ventricular ejection fraction (LVEF) is unclear.

Objective: The purpose of this study is to analyze exercise-induced PH determinants in patients with normal LVEF.

Methods and Results: Three hundred ninety-six subjects (160 male, mean age 55±13) referred for exercise echocardiography underwent a graded, symptom-limited, supine bicycle exercise with two-dimensional and Doppler echocardiography. Tricuspid regurgitation (TR) velocity was measured at rest and during exercise. Pulmonary artery systolic pressure (PASP) was estimated from TR velocity by adding a right atrial pressure of 10 mmHg. Patients were classified according to exercise induced PH, defined as present if PASP > 50 mmHg at 50 W of exercise. One hundred thirty-five patients (34%) had PASP > 50 mmHg during exercise. Patients with exercise-induced PH were older, more commonly female, and had shorter exercise duration; however, LVEF was significantly higher. The systolic blood pressure at rest and during exercise was significantly higher in patients with exercise-induced PH (rest, 125 ¡ 18 vs 132 ¡ 18 mmHg, p=0.0003; 25 W, 146 ¡ 21 vs 157 ¡ 21 mmHg, p<0.0001; 50 W, 157 ¡ 24 vs 170 ¡ 22 mmHg, p<0.0001; 75W, 168 ¡ 23 vs 183 ¡ 22 mmHg, p<0.0001).Despite similar resting oxygen saturation, exercise oxygen saturation was significantly lower in subjects with exercise-induced PH than in those without. Numerous echocardiographic variables were significantly different between groups. In multivariate analysis, resting TR velocity (p<0.0001), E/E¡ (p=0.027), age, and gender were the strongest predictors of PASP during exercise.

Conclusion: Exercise-induced PH is common even in subjects with normal LVEF. It is strongly associated with E/E¡ ratio, TR velocity, age, systolic blood pressure during exercise, and gender.