1.15 Assessment of Tricuspid Regurgitation

Normally, pulmonary artery pressure is higher or lower than systemic pressure?

Lower.

Low pressure in the right heart is due to what?

Large cross-sectional area of the pulmonary circulation which results in a lower resistance to blood flow.

What is pulmonary hypertension?

When there is an increase in the pulmonary vascular resistance.

PHTN can occur in response to what?

Chronic left sided heart disease such as MS, MR, cardiomyopathy, and ischemic disease.

PHTN occurs in patients with pulmonary disease such as?

COPD (chronic obstructive pulmonary disease) or with primary pulmonary hypertension. Other causes include left to right shunts (VSD, PDA) and scleroderma.

Echo and Doppler ultrasound in particular allows easy assessment of what?

RVSP or SPAP in the presence of TR

What views are used to calculate the TR velocity with CW Doppler?

LAX RVIT, SAX RVIT, 4C, 5C, and subcostal.

How is RVSP calculated?

RVSP = 4 (TR peak velocity)² + RAP

Normal RVSP is at what pressure?

18-30 mmHg

Mild PHTN is at what RVSP pressure?

30-40 mmHg

Moderate PHTN is at what RVSP pressure?

40-70 mmHg

Severe PHTN is at what RVSP pressure?

> 70 mmHg

Estimation of the RA pressure can be based upon what?

The collapsibility index of the IVC.

If the IVC does not collapse with inspiration, what should be perfromed?

A sniff test.

Dilatation of the iVC with normal RAP may occur in which patients?

Athletes and patients who are mechanically ventilated.

An IVC < 2.1 cm and with 50% decrease in size has an RA pressure of what?

0-5 mmHg

A dilated IVC > 2.1 cm and > 50% inspiratory collapse indicates what RA pressure?

6-10 mmHg

A dilated IVC > 2.1 cm and < 50% inspiratory collapse indicates what RA pressure?

10-15 mmHg

A dilated IVC > 2.1 cm with no collapse indicates what RA pressure?

> 15 mmHg

If there is a ventricular septal defect when assessing the RVSP, what should be done?

A blood pressure reading to obtain the systolic blood pressure. This will be used in the equation: RVSP mmHG = SBP - 4 (VSD peak velocity)²

In the presence of PDA (patent ductus arteriosus), what should be obtained?

A blood pressure reading to get the systolic blood pressure to use in the following equation: RVSP = SBP - 4 (PDA peak velocity)²

Estimation of the PAEDP from the pulmonary regurgitation cause be done because PR velocity reflects what?

The gradient between the PA and the RV during diastole.

What is the equation used for the PAEDP when there is a presence of PR?

PAEDP = 4 (PR end diastolic velocity)² + RAP

The accuracy of intracardiac pressure estimation is dependent upon what?

The accurate measurement of peak velocities.

Errors in peak velocities of pulmonary pressures are mostly related to what?

The intercept angle between the ultrasound beam and the direction of blood flow.

The maximum velocities are measured when the ultrasound beam is aligned…?

Parallel to the direction of blood flow, therefore it is crucial to ensure parallel alignment with flow. This may require off axis imaging.

BP errors of what are common?

5-10 mmHg

In normal young athletes, the IVC may be what?

Dilated in the presence pf normal RAP.

In ventilated patients, IVC is commonly?

Dialated.

Patients with arrhythmias (in particular atrial fibrillation) will have limitations to what?

Estimations of pulmonary pressure.