**Acknowledgements**

Figure 8 shows the RC curve of our IPAH and CTEPH patients. The data show an inverse Cp-PVR relationship which reflects the coupling of these two components of RV afterload. However, the CTEPH curve is displaced down and leftward with respect to the IPAH curve. For patients with the same PVR (isobaric steady afterload), preoperative operable CTEPH showed a lower Cp, reflecting a higher pulsatile afterload component. These results disagree with the findings of Lankhaar et al and might expose a different RC coupling in operable

Finally, we analyzed Zup in operable and inoperable CTEPH patients (Ruiz-Cano et al., 2010). Among operable patients with good outcomes one year after PEA, lower Zup is predictive of persistent PH (PVR ≥ 240 dyn.s.cm-5), which is associated with a lower improve‐ ment of Cp and pPAP. The lower Zup in inoperable CTEPH patients is in agreement with a more diffuse distribution of RV afterload seen in IPAH and would be related to different

**Figure 8.** PVR-Cp (pulmonary vascular resistance-capacitance) plot of CTEPH and idiopathic PAH patients (fill dia‐

Substantial advances have occurred over the past quarter century in the diagnostic and therapeutic approach to CTEPH. In terms of management, surgery (PEA) is likely to remain the mainstay of therapy for patients with CTEPH. Further studies are necessary to obtain reliable long-term data on the effect of medical therapies in patients with CTEPH. It would be beneficial to have more objective definitions of what is considered to be operable and inoper‐

monds represent ten normal subject without pulmonary hypertension) (Grignola et al., 2009b).

vascular wall remodeling (thrombus organization and small vessel arteriopathy).

CTEPH (Grignola et al., 2009b).

186 Pulmonary Hypertension

**5. Conclusions**

Juan C Grignola is supported by CSIC (Comisión Sectorial de Investigación Científica) and is a member of ANII (Agencia Nacional de Investigación e Innovación). María J Ruiz-Cano and Pilar Escribano are members of the REDINSCOR cardiovascular research network, which is supported by the Spanish Ministry of Health through the Instituto de Salud Carlos III.
