CHAPTER 20: Pulmonary Disorders

PULMONARY HYPERTENSION

• Pulmonary hypertension is defined as a mean pulmonary artery pressure >25 mm Hg.

• Echocardiography measures right ventricular systolic pressure.

• This is considered equal to the peak pulmonary artery pressure (in the absence of right ventricular outflow obstruction).

• Tracing the tricuspid regurgitation Doppler envelope can be used to determine the mean pulmonary artery pressure.

• The mean pressure is approximately two-thirds of the peak pressure.

• Technical caveats:

  • - Multiple windows are needed to obtain the fastest tricuspid regurgitation velocity. Otherwise the pressure will be underestimated.

  • - An overgained signal will overestimate the gradient.

  • - Common cause: Saline contrast can add noise to the Doppler envelope.

  • - Eccentric mitral regurgitation jets directed at the atrial septum should not be confused with tricuspid regurgitation jets.

  • - It is important to be familiar with the rare left ventricle–right atrium Gerbode defect.

Sources

• Tehrani F, Movahed MR. How to prevent echocardiographic misinterpretation of Gerbode type defect as pulmonary arterial hypertension. Eur J Echocardiogr. 2007;8:494–497.

• Milan A, Magnino C, Veglio F. Echocardiographic indexes for the non-invasive evaluation of pulmonary hemodynamics. J Am Soc Echocardiogr. 2010;23:225–239. (Fig. 20-1)

Comprehensive review.

DIASTOLIC PULMONARY ARTERY PRESSURE

• Patients with systolic pulmonary hypertension may also have elevated diastolic pulmonary artery pressures.

• The elevated diastolic pulmonary artery pressure increases the amount of regurgitation across the pulmonic valve.

• Echocardiographic examination reveals a larger color flow jet then what is seen in the normal patient with normal pulmonary artery pressures.

• The slope of the pulmonic regurgitation jet deceleration velocities reflects the rate of equalization of pressures between the pulmonary artery and the right ventricle.

• Normally, equalization is slow and the slope is flat.

• In patients with elevated right ventricular end-diastolic pressures, the slope is steep.

• An early diastolic maximum velocity >3 m/s may be present in some patients with severe systolic left heart failure. This indicates pulmonary diastolic hypertension with an early diastolic gradient of 36 mm Hg between the pulmonary artery and the right ventricle (Fig. 20-2).

• Severe pulmonic regurgitation and severe tricuspid regurgitation may create a volume overload of the right ventricle.

• Volume overload of the right ventricle results in chamber dilatation (Fig. 20-3).

• Right ventricular chamber dilatation with pressure overload (severe pulmonary systolic hypertension) is an ominous finding.

Source

• Stephen B, Dalal P, Berger M, ...