Objectives: 

Pulmonary circulation is a vascular system subject to certain pressure and volume conditions different from the systemic circulation. It is a system of low pressures and resistances, which functions under increased flow conditions and which creates a resistance by ten times lower than the systemic resistance. The purpose of our study was to determine the correlation between echocardiographic and haemodynamic data obtained by cardiac catheterization in patients with pulmonary hypertension.

Materials: 

Our study included 55 subjects diagnosed with pulmonary hypertension. They were examined by echocardiography and cardiac catheterization. The pulmonary resistance is quantified according to Ohm's law, by the ratio between the difference of pressure of the pulmonary artery and the pulmonary capillary pressure and the cardiac output. Cardiac catheterization is the reference method for determining the pulmonary resistance.The echocardiographic assessment of the pulmonary vascular resistances (PVR) was performed by three different methods: 1) The ratio between the maximum speed of the tricuspid regurgitation flow (max v TR) and velocity – time integral in the ejection tract of the right ventricle (VTIRVOT); 2) PVR = max v TR/ VTIRVOT x 10 + 0, 16; 3) The ratio between the systolic pulmonary artery pressure (sPAP) and the product between VTIRVOT and heart rate (HR): sPAP/ (VTIRVOT x HR). We determined the coefficient of linear correlation (Pearson) between the two methods.

Results: 

Pulmonary vascular resistance average value at cardiac catheterization was 10.4 ± 5.14 Wood units. We obtained excellent correlations between the two methods, regardless of the formula employed (r 0.79, 0.82, 0.72, respectively, p <0.001).

Conclusions: 

Echocardiography is an excellent noninvasive method for determining the pulmonary vascular resistance.