Doppler assessment of pulmonary haemodynamics in chronic hypoxic lung disease.

Various methods of Doppler echocardiography are useful in the analysis of flow dynamics within the heart and the pulmonary circulation in patients with COPD. In addition, to distinguish patients with increased pulmonary artery pressures from those with normal pressures, Doppler techniques provide quantitative methods for estimating pulmonary artery pressures non-invasively. Doppler echocardiography can be performed repeatedly and can thus be used to assess serial changes in the clinical state of a patient or in the response to certain pharmaceutical interventions in the pulmonary vascular bed. The most useful and accurate method of estimating pulmonary artery pressures in patients with chronic hypoxic lung disease is the systolic trans-tricuspid gradient, calculated from tricuspid regurgitation detected by continuous wave Doppler echocardiography with estimation of the right ventricular pressure, followed by the acceleration time from pulmonary flow analysis using pulsed Doppler techniques. New contrast materials to enhance the continuous wave Doppler signal and transoesophageal echocardiography may provide even more satisfactory results in the future.