Left and right ventricular power: outputs are the strongest hemodynamic correlates to allow identification of acute responders to vasodilator treatment in idiopathic pulmonary arterial hypertension.

Introduction: Despite the prognostic importance of traditionally derived measurements, the significance of right heart catheterization (RHC) remains controversial. Thus, a continued search for hemodynamic markers that define better responsive patients is required. Since, right ventricular failure is the most fatal pathway, right (RVPO) and left (LVPO) ventricular power output are parameters that could provide input for a better understanding of the hemodynamics involved in idiopathic pulmonary artery hypertension (IPAH).

Method: We retrospectively analyzed how demographics and outcome correlate with hemodynamics to identify responders among IPAH patients.

Results: Ninety patients fulfilled the following criteria for inclusion in this study: (1) complete RHC at baseline; (2) an acute evaluation for vasodilators (AEFV, including a positive response, that is, an increase in CO, a decrease in both mPAP and pulmonary vascular resistance (≥ 20% from baseline, respectively); and (3) a long-term follow-up under accepted IPAH treatments. If RVPO decreased (p < 0.001) and LVPO increased (p < 0.012) during AEFV, it is considered that these findings reinforce our ability to identify responders; that is, patients that remained as responders after 6.4 ± 3 years under nifedipine treatment (37.7% of the studied IPAH population). After multivariate analysis, age, RVPO, and LVPO remained as independent variables (OR = 0.927, 95%CI: 0.87-0.98, p = 0.01; OR = 0.114, 95%CI: 0.00-0.91, p = 0.045; and OR = 171.5, 95% CI: 5.3-549, p = 0.004, respectively) when estimating the probability of being a responder. On this basis, an equation was derived to identify responders among IPAH patients, where the probability of being a responder = 1.0196-0.0631 (age) - 4.7693 (RVPO) + 3.8152 (LVPO), ROC: 0.76, 95% CI: 0.63-0.89; p = 0.001.

Conclusion: based on the proposed equation, LVPO and RVPO could be used for the identification of responders among IPAH patients.