[Non-invasive assessment of the peak pressure gradient between the aorta and pulmonary artery in patent ductus arteriosus].

The validity of continuous wave Doppler ultrasound estimation of the peak pressure gradient between the aorta (Ao) and pulmonary artery (PA) in patients with patent ductus arteriosus (PDA) was evaluated. Ten patients, all without other anomalies, underwent cardiac catheterization and cine-angiography, and the peak pressure gradient between the Ao and PA (dP(C)) was measured during catheterization. In all cases the mean PA pressure was less than 35 mmHg. According to the angiographic findings, the patients were categorized as Group A, consisting of seven patients whose features of the ductus were wedge- or tube-like in configuration; Group B, consisting of two patients whose features were termed "orifice-like" stenosis including one with abrupt narrowing on the PA side of the ductus and the other with a short segmental ductus. Group C consisted of one patient who had a long curved segmental ductus. The maximum velocity of ductus flow was measured by continuous wave Doppler ultrasonography, and the estimated peak pressure gradient between the Ao and PA by Doppler (dP(D] was calculated using the simplified Bernoulli equation (dP = 4V2). In group A, dP(D) was overestimated compared to dP(C) in all patients by 19 to 51 mmHg (mean 34 mmHg). However, in group B, the difference between dP(D) and dP(C) was small, 5 mmHg and 7 mmHg, respectively. In group C, dP(D) was underestimated as opposed to dP(C). Thus, in the limited cases, the simplified Bernoulli equation could be used in estimating the peak pressure gradient between the Ao and PA. However, this equation leads to overestimation in many cases.(ABSTRACT TRUNCATED AT 250 WORDS)