Complex sentence: The only vascular agent that has shown scientific evidence of efficacy and is the most widely studied pharmaceutical in both controlled laboratory and field trials is Lasix/furosemide which decreases pulmonary arterial pressure via its diuretic effects, bronchodilates, and redistributes blood flow during exercise.
Split into simpler sentences: The only vascular agent that has shown scientific evidence of efficacy and is the most widely studied pharmaceutical in both controlled laboratory and field trials is Lasix/furosemide. Furosemide decreases pulmonary arterial pressure via its diuretic effects, bronchodilates, and redistributes blood flow during exercise.