Sixty patients ( 42 men ; mean age , 66.6 9.2 yr ) , with a mean pulmonary artery pressure of 36.0 ( 8.9 ) mm Hg , PVRi 13.0 ( 6.7 ) Wood Units/m ( 2 ) and reduced cardiac index of 2.21 ( 0.5 ) L/min/m ( 2 ) were recruited to the study .