Is the respiratory (resp) variation connected to the transthoracic (TR) gradient?

From the Guidelines

Respiratory variation and the TR gradient are indeed connected in cardiac physiology, as evidenced by the fact that marked respiratory variation in TR velocity suggests an elevated right atrial pressure 1. The connection between respiratory variation and the TR gradient is crucial in understanding right heart hemodynamics. During normal respiration, the TR gradient typically increases during inspiration and decreases during expiration due to changes in intrathoracic pressure, which affects venous return to the right heart and subsequently the pressure gradient across the tricuspid valve when regurgitation is present. Key points to consider include:

• The estimation of pulmonary artery systolic pressure is based on the peak velocity of the jet of tricuspid regurgitation, using the simplified Bernoulli equation to describe the relationship between tricuspid regurgitation velocity and the peak pressure gradient of tricuspid regurgitation 1.
• Right atrial pressure can be estimated based on the diameter and respiratory variation of the inferior vena cava, although often a fixed value of 5 or 10 mmHg is assumed 1.
• Marked respiratory variation in TR velocity, such as decreased TR velocity with inspiration, suggests an elevated right atrial pressure, which is indicative of conditions like constrictive pericarditis or cardiac tamponade 1. When evaluating right heart hemodynamics with echocardiography, it's essential to record TR measurements throughout the respiratory cycle and note the phase in which measurements are taken, as this connection helps clinicians properly interpret TR gradients when estimating pulmonary artery pressures and assessing right heart function in various cardiopulmonary conditions.

From the Research

Connection between Resp Variation and TR Gradient

• The connection between resp variation and TR gradient is not directly addressed in the provided studies 2, 3, 4, 5, 6.
• However, the studies discuss the importance of imaging modalities such as echocardiography in assessing tricuspid regurgitation (TR) and its severity 2, 3, 4, 5.
• Transthoracic and transesophageal echocardiography are used to evaluate TR, including the assessment of tricuspid annular area, leaflet characteristics, and right ventricular dimensions 2, 3, 4, 5.
• The studies also highlight the role of echocardiography in guiding transcatheter edge-to-edge repair (TEER) for TR, including patient selection and procedural guidance 5.
• Additionally, the safety of transesophageal echocardiography in patients with tricuspid valve disease is assessed, with findings indicating a higher prevalence of adverse events in patients with severe tricuspid regurgitation 6.

Imaging Modalities for TR Assessment

• Echocardiography, including transthoracic and transesophageal echocardiography, is a crucial imaging modality for assessing TR and its severity 2, 3, 4, 5.
• Three-dimensional transthoracic echocardiography has been shown to have good reliability in defining tricuspid valve function, leaflet characteristics, and geometry compared to second-level imaging modalities 4.
• Magnetic resonance imaging (MRI) is also used to quantify TR severity, with studies comparing MRI to echocardiography in terms of correlation and discrimination of severe TR 3.

Clinical Implications

• The assessment of TR and its severity is crucial for guiding treatment decisions, including transcatheter edge-to-edge repair (TEER) 5.
• Patient selection for TEER is critical, with echocardiography playing a key role in determining eligibility 5.
• The safety of transesophageal echocardiography in patients with tricuspid valve disease is an important consideration, with findings indicating a need for careful patient selection and monitoring 6.