The Secrets About Tricuspid Regurgitation

Physics of Doppler Waveforms and Expert Scanning Techniques

Overview

Retrograde flow from the right ventricle into the right atrium during ventricular systole is commonly referred to as tricuspid regurgitation (TR). This valvulopathy can occur in the acute or chronic setting and is typically the most tolerated form of regurgitation. Tricuspid regurgitation represents the pressure difference between the right ventricle and right atrium; echocardiography is a non-invasive modality that is used to quantify the right ventricular systolic pressure (RVSP).

Relevance

Pulmonary artery systolic pressure (PASP) is equivalent to RVSP if there is no obstruction in the right ventricular outflow tract. Both of these parameters are used to assess the presence and severity of pulmonary hypertension (PAH); it can correlate with enlargement of the right heart, heart failure, pulmonary emboli, arrhythmias, and bleeding within the lungs. According to recent data by the Cleveland Clinic, pulmonary hypertension affects nearly 100% of patients with severe mitral valve disease and 65% of patients with aortic valve disease (Cleveland Clinic, 2024). The golden standard for assessing pressures in the right heart is via a right heart catheterization but transthoracic echocardiography (TTE) is the modality of choice as it is readily available, portable, and most importantly non-invasive.

In this comprehensive lesson we will discuss origins, scanning tricks, Doppler shapes, physics, & more…

Overall, pulmonary hypertension is high blood pressure in the lungs that negatively restricts the pulmonary artery, making it more difficult to deliver deoxygenated blood. Cardiovascular disease, lung disease, and hypoxia are some of the common causes for PAH. Additionally, it puts stress on the right ventricle, as it needs to work harder to overcome the higher pressure downstream. Right ventricular dilation and remodeling can occur and cause secondary tricuspid regurgitation as discussed below.

Origins of TR

Primary or Degenerative: directly connected to the tricuspid leaflets’ inability to close (endocarditis, Ebstein’s anomaly, myxomatous degeneration, carcinoid, or rheumatic valve disease.)

Secondary or Functional: as a result of ventricular remodeling (non-ischemic and ischemic cardiomyopathies, RV dysfunction, RV volume overload, RV cardiomyopathy, pacemaker or defibrillator induced, pulmonary hypertension, atrial fibrillation, pulmonary embolism, chronic lung disease, pulmonary hypertension, shunt.)

Objectives with TTE

Aligning the continuous wave Doppler line parallel to flow is the first step for achieving the highest TR velocity. This form of Doppler has range ambiguity and quantifies the peak velocity along the scan line without aliasing, whereas pulsed waved Doppler is targeted to a specific location and can alias. Imaging the tricuspid valve in multiple views ensures that we are seeing the regurgitant jet and noting the direction of flow for proper Doppler gate placement.