From the Guidelines
Respiratory variation greater than 50% in the tricuspid valve flow velocity is a significant echocardiographic finding that strongly suggests the presence of cardiac tamponade or severe tricuspid regurgitation. This finding occurs when there is excessive fluid accumulation in the pericardial space, causing compression of the heart chambers and impaired filling during inspiration, or when there is a significant backflow of blood from the right ventricle to the right atrium during systole 1. During normal respiration, right ventricular filling increases during inspiration, but in tamponade or severe tricuspid regurgitation, this normal physiologic variation becomes exaggerated due to the competing pressures from the pericardial effusion or the backflow of blood.
Some key points to consider in the assessment of tricuspid valve disease include:
- The clinical presentation, diagnosis, grading, and dynamic nature of the disease 1
- The use of echocardiography to assess the severity of tricuspid regurgitation, including the measurement of tricuspid valve inflow velocity and the assessment of hepatic vein flow 1
- The importance of considering the influence of right ventricular failure and tricuspid annular dilatation on the decision to intervene surgically 1
This exaggerated respiratory variation manifests as a greater than 50% decrease in tricuspid valve inflow velocity during inspiration compared to expiration. This finding should prompt immediate clinical correlation with other signs of tamponade or severe tricuspid regurgitation, such as hypotension, elevated jugular venous pressure, and pulsus paradoxus. If cardiac tamponade is confirmed, urgent pericardiocentesis is typically required to drain the fluid and relieve the cardiac compression. The procedure should be performed by an experienced clinician, often with echocardiographic or fluoroscopic guidance, to safely remove the pericardial fluid and restore normal hemodynamics. In the case of severe tricuspid regurgitation, treatment options may include medical therapies, such as diuretic agents and afterload reduction with pulmonary vasodilators, or surgical intervention, such as tricuspid valve repair or replacement 1.
From the Research
Respiratory Variation in Tricuspid Valve Regurgitation
- Respiratory variation in tricuspid regurgitation (TR) systolic velocities can be used to diagnose severe TR 2
- A difference in TR velocity ≥0.6 m/s has a sensitivity of 66%, specificity of 94%, positive predictive value of 92%, and a negative predictive value of 74% for diagnosing severe TR 2
- Excessive respiratory changes in Doppler measurements of TR systolic velocities are a specific sign of severe TR 2
- Respiratory variation > 50% in the tricuspid valve is not directly mentioned in the provided studies, but excessive respiratory changes in TR velocities are associated with signs of more severe TR, such as greater right ventricular size and malcoaptation of the tricuspid valve leaflets 2
Hemodynamic Findings in Severe Tricuspid Regurgitation
- Hemodynamic changes in right atrial (RA) pressures in severe TR include elevated mean pressures, a large systolic wave called an "s" wave, a prominent 'Y' descent and a blunted 'X' descent 3
- RV end diastolic pressure is elevated and cardiac output is reduced, especially with exercise, in patients with severe TR 3
- "Ventricularization" of the RA pressure tracing is a specific finding in severe TR, but it is found in a minority of patients 3
Echocardiographic Evaluation of Tricuspid Regurgitation
- Echocardiography can assess the TR etiology/severity, measure RA and RV size and function, estimate pulmonary pressure, and characterize LV disease 4
- Multi-modality imaging, in particular echocardiography, is paramount in determining the mechanism, severity, and potential treatment options of TR 5
- Proposed echocardiographic and Doppler considerations can be applied to gain a qualitative impression of the "significance or severity" of TR, but caution is urged in applying them due to limited literature 6