The Effect of Exercise on Endothelin 1 Level in Patients with Pulmonary Hypertension

Purpose Endothelin-1 (ET-1), a potent vasoconstrictor, is elevated in heart failure as well as in pulmonary arterial hypertension (PAH). To our knowledge little is known about ET-1 level in exercise induced pulmonary hypertension when compared to group 1 and 2 pulmonary hypertension. We aim to assess effect of exercise on ET-1 levels in different types of pulmonary hypertension. Methods A prospective study measuring ET-1 level in patient with PAH, heart failure induced pulmonary hypertension (D-PH), exercise induced PAH and exercise induced D-PH both at rest at peak exercise. Demographic and echo data were collected. Right heart cath was done to confirm diagnosis and type of pulmonary hypertension, which was followed by arm lifting exercise for 4 minutes (30 watts and decrease of MVO2 by >10%) using different weights. Exercise induced PAH defined as mean pulmonary pressure (mPA) 30 mmHg and pulmonary wedge (PW) 30 mmHg and PW >20 mmHg. Blood samples were collected to measure ET-1 level using ET-1 ELISA. Results A total of 77 patients were included in this study. 5 study groups were divided into: 10 control subjects, 18 patients with D-PH, 22 patients with PAH, 15 patients with Exercise D-PH and 12 patients with Exercise PAH. At rest, ET-1 level was the highest in Exercise-PAH compared to other groups 3.6 +/- 2 with p valule 0.04. Whereas, at peak exercise, ET-1 level was the highest in PAH compared to other groups with, 2.91 +/- 1.8 with p value of 0.05 (figure 1). Patients with D-PH had more evidence of diabetes mellitus, Obesity, smoking, dilated right atrium, right ventricular failure and were more elderly male. Conclusion At rest, ET-1 level is the highest in patients with exercise induced PAH, whereas at peak exercise, ET-1 is the highest in patients with PAH. Patients with heart failure induced pulmonary hypertension have more cardiac risk factors with evidence of right sided failure.