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. Author manuscript; available in PMC: 2012 Mar 22.
Published in final edited form as: Circulation. 2011 Mar 7;123(11):1185–1193. doi: 10.1161/CIRCULATIONAHA.110.981746

Table 4.

Regression modeling results for exercise measurements, stratified by serum brain natriuretic peptide (BNP), presented as coefficient, 95% confidence interval (CI), and p value

BNP ≥ 100 pg/ml (n = 12) BNP < 100 pg/ml (n = 16)
Coefficient 95% CI p Coefficient 95% CI p p*
Measurements at peak exercise
  Oxygen consumption, ml/kg/min 0.50 (−1.38, 2.38) 0.60 −0.98 (−2.60, 0.65) 0.23 0.24
  Heart rate, beats/min −2.17 (−5.62, 1.29) 0.22 −1.46 (−4.46, 1.54) 0.34 0.76
  Respiratory rate, breaths/min −1.24 (−2.76, 0.28) 0.11 −2.76 (−4.04, −1.48) < 0.01 0.13
  Minute ventilation, L/min −3.15 (−6.77, 0.47) 0.09 −5.74 (−8.86, −2.61) < 0.01 0.28
  Oxygen saturation, % 0.51 (−0.29, 1.32) 0.21 0.41 (−0.28, 1.10) 0.25 0.84
Measurements at anaerobic threshold
  Oxygen consumption, ml/kg/min 1.85 (0.59, 3.12) < 0.01 0.68 (−0.39, 1.75) 0.21 0.14
  Respiratory rate, breaths/min −1.26 (−3.22, 0.69) 0.20 −2.37 (−4.11, −0.62) 0.01 0.39
  Minute ventilation, L/min 0.49 (−1.37, 2.34) 0.60 −0.94 (−2.57, 0.69) 0.25 0.24
  VE/VCO2 −2.40 (−3.69, −1.12) < 0.01 −1.43 (−2.67, −0.19) 0.02 0.27

Each regression coefficient corresponds to difference in average post-phase outcome between sildenafil and placebo, adjusted for pre-phase values, study period, and treatment sequence. VE/VCO2: ventilatory equivalents of carbon dioxide.

*

p-value from test of interaction evaluating whether the treatment difference is equal in the two BNP strata.