Sex-specific cardiopulmonary exercise testing parameters as predictors in patients with idiopathic pulmonary arterial hypertension

Yuan P, Ni HJ, Chen TX, Pudasaini B, Jiang R, Liu H, Zhao
QH, Wang L, Gong SG, Liu JM

Hypertens Res. 2017 Oct 5;40(10):868-875. doi: 10.1038/hr.2017.52. Epub 2017 Jun

Cardiopulmonary exercise testing (CPET) has been used for prognosis in idiopathic
pulmonary arterial hypertension (IPAH). We explored whether sex differences had
an impact on prognostic assessments of CPET in IPAH. Data were retrieved from 21
male and 36 female incident IPAH patients who underwent both right heart
catheterization and CPET from 2010 to 2016 at Shanghai Pulmonary Hospital. Cox
proportional hazards analysis was used to assess the prognostic value of CPET.
The mean duration of follow-up was 22±15 months. Nine men and 15 women had an
event. The differences in clinical parameters in the whole population were not
the same as the inter-subgroup differences. Event-free women had significantly
higher cardiac output, lower pulmonary vascular resistance and percentage of
predicted FVC compared with event men (all P<0.05). Event-free men had
significantly higher end-tidal partial pressure of CO2 (PETCO2) at anaerobic
threshold (AT), peak workload, PETCO2, maximum oxygen consumption (VO2)/minute
ventilation (VE), and oxygen uptake efficiency slope and lower end-tidal partial
pressure of O2 (PETO2) at AT, peak PETO2, and lowest VE/VCO2 compared with event
men. Event-free women had dramatically higher peak VO2, VCO2, VE and O2 pulse
than event women (all P<0.05). Peak PETCO2 was the independent predictor of
event-free survival in all patients and males, whereas peak O2 pulse was the
independent predictor of event-free survival in females. Men with peak
PETCO2⩾20.50 mm Hg, women with peak O2 pulse ⩾6.25 ml per beat and all patients
with peak PETCO2⩾27.03 mm Hg had significantly better event-free survival.
Sex-specific CPET parameters are predictors of poor outcomes. Decreased peak
PETCO2 in men and peak O2 pulse in women were associated with lower event-free
survival in IPAH.