AIMS: The most recent European guidelines have proposed new definitions of pulmonary hypertension (PH) in left heart disease, to better approach the characteristics required to reflect the presence of pulmonary vascular disease. The purpose of this study was to assess whether different haemodynamic definitions of post-capillary PH imply a different reversibility of PH in response to acute vasodilator administration in heart failure patients with reduced ejection fraction and PH (HFrEF-PH).
METHODS AND RESULTS: Right heart catheterization and reversibility testing was performed in 156 HFrEF-PH patients. Patients were classified as combined post-capillary and pre-capillary pulmonary hypertension (Cpc-PH) vs. isolated post-capillary pulmonary hypertension (Ipc-PH) and on the basis of diastolic pressure gradient (DPG) ≥ 7 vs. < 7 mmHg or of transpulmonary gradient (TPG) >12 vs. ≤12 mmHg. After vasodilator administration, Cpc-PH patients showed a greater per cent improvement in pulmonary vascular resistance (PVR), DPG and TPG as compared with Ipc-PH patients (all Pint< 0.001); only pulmonary compliance (PCa) improved less in Cpc-PH than in Ipc-PH patients (Pint= 0.007). However, despite vasodilatation, Cpc-PH patients remained in an unfavourable portion of the inverse hyperbolic relationship between PVR and PCa. The number of patients in whom PVR was reduced below 2.5 wood units was similar in Cpc-PH, DPG ≥7 mmHg and TPG >12 mmHg groups (28.3, 26.7 and 18.9%, respectively).
CONCLUSION: Although substantial improvements in PVR, DPG and TPG were observed in Cpc-PH patients after acute vasodilator administration, this response was associated with persistent abnormalities in the PVR vs. PCa relationship. The link between baseline right heart haemodynamics and pulmonary vascular disease remains elusive.