What Is the Prognostic Significance of Pulmonary Hypertension in Heart Failure?

Abstract

Increased left ventricular filling pressure is a hallmark of heart failure (HF) caused by left ventricular dysfunction (LVD). Within the closed hemodynamic system, increased LV filling pressure results in elevated pressures in the left atrium and pulmonary venous vasculature. When pulmonary hypertension (PH, defined by mean pulmonary artery pressure [mPAP] >25 mm Hg) is associated with an abnormally elevated pulmonary capillary wedge pressure (PCWP >15 mm Hg) or left ventricular end-diastolic pressure (LVEDP >18 mm Hg),1 it has been variably termed World Health Organization (WHO) Group 2 PH,1 pulmonary venous hypertension,2 “postcapillary PH,”3 or “passive PH.”4 Article see p 644 Patients with LVD also have a propensity to develop a precapillary pulmonary arterial contribution to PH, reflected by an increased transpulmonary gradient (TPG, defined as mPAP-PCWP that exceeds 12 to 15 mm Hg) or an elevated pulmonary vascular resistance (PVR, defined as TPG/cardiac output that exceeds 2.5 to 3 Wood units [WU]).5,6 This type of PH, which is “out of proportion” to underlying left-sided disease in the setting of normalized volume status, has been termed “mixed PH,” given both precapillary and postcapillary contributions to elevated PAP.7 PH in HF can be simplistically organized along 2 sequential dyads: (1) the presence or absence of a significant precapillary contribution to elevated PAP (ie, mixed PH as opposed to purely passive PH) and (2) if present, the relative fixed (ie, nonreversible with lowering left-sided filling pressures) or reactive (ie, reversible with reduction of left-sided filling pressures) character of the precapillary contribution to PH (Figure). Figure. Diagnostic framework for pulmonary hypertension in heart failure (HF). mPAP indicates mean pulmonary artery pressure; PCWP, pulmonary capillary wedge pressure; PVR, pulmonary vascular resistance; and PH, pulmonary hypertension. There are no widely established cut-points to define PVR and transpulmonary …