From the Guidelines
A transthoracic echocardiogram (TTE) should evaluate the severity of tricuspid regurgitation, determine the etiology, measure the sizes of right-sided chambers and inferior vena cava, assess right ventricular systolic function, estimate pulmonary artery systolic pressure, and characterize any associated left-sided heart disease in a patient with elevated right atrial pressure. When evaluating a patient with elevated right atrial pressure, it is crucial to assess the right ventricular size and function, as well as the tricuspid valve function, to determine the underlying cause of the elevated pressure 1. The assessment should include:
- Right ventricular dimensions and systolic function to look for signs of dilation, hypertrophy, or reduced contractility
- Tricuspid valve evaluation to assess regurgitation severity and any structural abnormalities
- Estimation of pulmonary artery systolic pressure to determine if pulmonary hypertension is contributing to the elevated right atrial pressure
- Measurement of the inferior vena cava diameter and assessment of its respiratory variation to provide additional confirmation of right atrial pressure elevation
- Evaluation of left ventricular function and the presence of any septal flattening suggesting right ventricular pressure or volume overload
- Assessment for any intracardiac shunts, pericardial effusion or constriction, and valvular abnormalities that might cause secondary right heart dysfunction, as recommended by the 2014 AHA/ACC guideline for the management of patients with valvular heart disease 1. This comprehensive evaluation is essential to identify the underlying cause of elevated right atrial pressure and guide appropriate management.
From the Research
Evaluation of Right Atrial Pressure using Transthoracic Echocardiogram (TTE)
In patients with elevated right atrial pressure, a Transthoracic Echocardiogram (TTE) should evaluate the following parameters:
- Inferior vena cava (IVC) diameter and collapsibility index, as studies have shown that IVC diameter ≥2 cm and IVC respirophasic collapse <40% correlate with right atrial pressure (RAP) 2, 3
- Right atrial volume index (RAVi), as 3D-RAVi ≥35 ml/m(2) has been shown to be a reliable predictor of RAP >10 mmHg 2
- Right atrial reservoir strain (RASr) assessed by speckle-tracking echocardiography, as RASr has been shown to demonstrate good ability to identify elevated RAP and relatively stronger diagnostic performance when compared with conventional non-invasive measures 4
- Tricuspid E wave velocity and right ventricular free wall tissue Doppler velocities, as these parameters have been shown to correlate with mean RAP in certain populations 5
Parameters to Assess
The following parameters should be assessed during a TTE to evaluate right atrial pressure:
- IVC diameter and collapsibility index
- Right atrial volume index (RAVi)
- Right atrial reservoir strain (RASr)
- Tricuspid E wave velocity and right ventricular free wall tissue Doppler velocities
- Hepatic vein systolic filling fraction (SFF), although this parameter has been shown to have no relation to mean RAP in certain populations 5
Clinical Implications
Estimation of right atrial pressure using TTE has important clinical implications, including: