Management of pulmonary hypertension due to heart failure with preserved ejection fraction

Heart Failure with Preserved Ejection Fraction and Pulmonary Hypertension: Focus on Phosphodiesterase Inhibitors

Pulmonary hypertension (PH) is common in patients with heart failure with preserved ejection fraction (HFpEF). A chronic increase in mean left atrial pressure leads to passive remodeling in pulmonary veins and capillaries and modest PH (isolated postcapillary PH, Ipc-PH) and is not associated with significant right ventricular dysfunction. In approximately 20% of patients with HFpEF, "precapillary" alterations of pulmonary vasculature occur with the development of the combined pre- and post-capillary PH (Cpc-PH), pertaining to a poor prognosis. Current data indicate that pulmonary vasculopathy may be at least partially reversible and thus serves as a therapeutic target in HFpEF. Pulmonary vascular targeted therapies, including phosphodiesterase (PDE) inhibitors, may have a valuable role in the management of patients with PH-HFpEF. In studies of Cpc-PH and HFpEF, PDE type 5 inhibitors were effective in long-term follow-up, decreasing pulmonary artery pressure and improving RV contractility, whereas studies of Ipc-PH did not show any benefit. Randomized trials are essential to elucidate the actual value of PDE inhibition in selected patients with PH-HFpEF, especially in those with invasively confirmed Cpc-PH who are most likely to benefit from such treatment.

Structural and Hemodynamic Changes of the Right Ventricle in PH-HFpEF

One of the most important diagnostic challenges in clinical practice is the distinction between pulmonary hypertension (PH) due to primitive pulmonary arterial hypertension (PAH) and PH due to left heart diseases. Both conditions share some common characteristics and pathophysiological pathways, making the two processes similar in several aspects. Their diagnostic differentiation is based on hemodynamic data on right heart catheterization, cardiac structural modifications, and therapeutic response. More specifically, PH secondary to heart failure with preserved ejection fraction (HFpEF) shares features with type 1 PH (PAH), especially when the combined pre- and post-capillary form (CpcPH) takes place in advanced stages of the disease. Right ventricular (RV) dysfunction is a common consequence related to worse prognosis and lower survival. This condition has recently been identified with a new classification based on clinical signs and progression markers. The role and prevalence of PH and RV dysfunction in HFpEF remain poorly identified, with wide variability in the literature reported from the largest clinical trials. Different parenchymal and vascular alterations affect the two diseases. Capillaries and arteriole vasoconstriction, vascular obliteration, and pulmonary blood fluid redistribution from the basal to the apical district are typical manifestations of type 1 PH. Conversely, PH related to HFpEF is primarily due to an increase of venules/capillaries parietal fibrosis, extracellular matrix deposition, and myocyte hypertrophy with a secondary “arteriolarization” of the vessels. Since the development of structural changes and the therapeutic target substantially differ, a better understanding of pathobiological processes underneath PH-HFpEF, and the identification of potential maladaptive RV mechanisms with an appropriate diagnostic tool, become mandatory in order to distinguish and manage these two similar forms of pulmonary hypertension.

Pulmonary arterial hypertension and heart failure with preserved ejection fraction: are they so discordant?

Heart failure with preserved ejection fraction (HFpEF) and pulmonary arterial hypertension (PAH) are two emerging diseases focusing the attention of numerous researchers. In the last PAH guideline, there is a crossroad between the two diseases and pulmonary hypertension (PH) due to heart failure (HF) is categorized as subtype 2. In order to assess the correct diagnosis and management, it should be better understood the points of convergence and divergence of two diseases. Although, risk factors, demographic characteristics and haemodynamics are different, we report several similarities regarding vascular alterations, some aspects of cardiac remodelling, and clinical presentation. This model suggests HFpEF and PAH as two comparable conditions, with different cardiac adaptation and trajectories, linked to the intrinsic properties of either right and left ventricles. In both diseases the early pathophysiological mechanisms appear to begin from peripheral vasculature and to be backward transmitted to the larger arterial vascular district, and eventually to the myocardial structure. In this paper we would propose a simple approach to recognize the concordances and, all at once, distinguish the peculiarities of the two diseases.