Ventilatory power, a cardiopulmonary exercise testing parameter for the prediction of pulmonary hypertension at right heart catheterization

Abstract

Background: Several cardiopulmonary exercise test (CPET) parameters (peak VO2, PetCO2 and VE/VCO2) emerged as tools for the prediction of pulmonary arterial hypertension (PAH). Less is known on ventilatory power (VP) in patients with suspect PAH. Aim: To ascertain possible correlations between VP derived at CPET and hemodynamic parameters at right heart catheterization (RHC) indicative of PH. Methods: Forty-seven consecutive outpatients with suspect of PAH were assessed by CPET and RHC; VP was defined as peak SBP divided by the minute ventilation-CO2 production slope at CPET and Diastolic Pressure Gradient (DPG), Trans-pulmonary Pressure Gradient (TPG), mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance (PVR) at RHC were also assessed and compared with VP. Results: VP values were inversely related to mPAP (r −0.427, p 0.003), DPG (r −0.36, p 0.019), TPG (r: −0.43, p 0.004), and PVR (r −0.52, p 0.001). Correlations remained significant even after correction at multivariate analysis for age and gender. VP values below median identified subjects with mPAP ≥ 25 mmHg with an odds ratio of 4.5 (95% confidence interval 1.05–19.36, p < 0.05), an accuracy of 0.712 at ROC curve analysis (95% confidence interval 0.534–0.852, p < 0.05) and a positive predictive power 82%. Conclusions: In patients with suspected PAH, VP assessed at CPET might provide further information in predicting PAH at RHC. Correlations with PVR and DPG may be helpful in differentiating patients with isolated post-capillary PH from those with combined post-capillary and pre-capillary.

Keywords

• Ventilatory power
• Diastolic pressure gradient
• Transpulmonary pressure gradient
• Pulmonary vascular resistance
• Cardiopulmonary exercise test