|   | 
        Peak    VO2, mL/kg/min | 
        Mean    pulmonary artery pressure, mmHg | 
        Pulmonary    vascular resistance index, Wood units•m2 | 
        Cardiac    index, L/min/m2 | 
       
      
        | Percentage    Change From Baseline | 
        n | 
        0% | 
        10% | 
        20% | 
        n | 
        0% | 
        10% | 
        20% | 
        n | 
        0% | 
        10% | 
        20% | 
        n | 
        0% | 
        10% | 
        20% | 
       
      
        | Placebo | 
        29 | 
        55.2 | 
        72.4 | 
        89.7 | 
        56 | 
        50.0 | 
        67.9 | 
        76.8 | 
        50 | 
        48.0 | 
        60.0 | 
        62.0 | 
        52 | 
        61.5 | 
        67.3 | 
        78.8 | 
       
      
        | All    Sildenafil Doses Combined | 
        77 | 
        24.7 | 
        37.7 | 
        76.6 | 
        165 | 
        67.3 | 
        77.6 | 
        87.3 | 
        152 | 
        64.5 | 
        72.4 | 
        75.0 | 
        154 | 
        47.4 | 
        57.1 | 
        63.6 | 
       
      
        |  Low Dose | 
        24 | 
        37.5 | 
        50.0 | 
        79.2 | 
        39 | 
        48.7 | 
        69.2 | 
        82.1 | 
        36 | 
        52.8 | 
        66.7 | 
        66.7 | 
        37 | 
        48.6 | 
        56.8 | 
        67.6 | 
       
      
        |  Medium Dose | 
        26 | 
        19.2 | 
        34.6 | 
        73.1 | 
        55 | 
        74.5 | 
        80.0 | 
        85.5 | 
        49 | 
        65.3 | 
        75.5 | 
        77.6 | 
        49 | 
        51.0 | 
        59.2 | 
        63.3 | 
       
      
        |  High Dose | 
        27 | 
        18.5 | 
        29.6 | 
        77.8 | 
        71 | 
        71.8 | 
        80.3 | 
        91.5 | 
        67 | 
        70.1 | 
        73.1 | 
        77.6 | 
        68 | 
        44.1 | 
        55.9 | 
        61.8 | 
       
     
    VO2=oxygen consumption. 
    Numbers represent the percentage of patients having less than or equal to the specified percentage change from baseline for each parameter. |