Elevated Right Heart Pressures: Causes and Mechanisms

Primary Mechanisms

Elevated right heart pressures result from three primary mechanisms: increased pulmonary vascular resistance, elevated left-sided filling pressures transmitted backward through the pulmonary circulation, and high-output states that overwhelm the pulmonary vascular bed, as stated by the American College of Cardiology 1, 2
The American College of Cardiology recommends considering these mechanisms in the diagnosis and treatment of elevated right heart pressures 1, 2

In patients with COPD and chronic respiratory disease, elevated right heart pressures develop through hypoxic pulmonary vasoconstriction, destruction of the pulmonary vascular bed, and extensive remodeling of the pulmonary arterial walls, with approximately 50% of patients with severe COPD developing pulmonary hypertension 3

Left ventricular systolic or diastolic dysfunction, valvular disease, and elevated left atrial pressure are the most common causes of elevated pulmonary artery pressures, with about 22% of patients having elevated pulmonary capillary wedge pressures (>15 mm Hg) 4
The American College of Cardiology notes that left ventricular diastolic dysfunction increases with age and is independently associated with elevated pulmonary artery systolic pressure 4
The transpulmonary gradient is NOT significantly elevated in patients whose pulmonary hypertension is due to left heart disease, distinguishing this from true pulmonary arterial hypertension, as stated by the American College of Cardiology 1, 2

Pulmonary vascular resistance distinguishes passive pulmonary hypertension from pulmonary hypertension caused by pulmonary vascular disease, with right heart catheterization required to confirm the diagnosis and define the hemodynamic profile, according to the American College of Cardiology 1, 2
The American College of Cardiology recommends that pulmonary arterial hypertension be diagnosed with both mean pulmonary artery pressure >25 mm Hg AND pulmonary vascular resistance >3 Wood units after excluding lung disease, thromboembolic disease, left ventricular disease, or valve disease 1, 2

Progressive right heart failure increases in prevalence with more advanced left heart failure, occurring in approximately 48% of patients with heart failure with reduced ejection fraction, and is associated with 2.4-fold increased risk of mortality, as reported in Circulation 5
Right ventricular dysfunction is more common in nonischemic dilated cardiomyopathy (65%) compared with ischemic cardiomyopathy (16%), according to Circulation 5