Patent ducts arteriosus with pulmonary hypertension.

In most cases of patent ductus arteriosus the diagnosis is readily made on recognition of the typical murmur. In some, however, the continuous murmur is lacking, and a systolic murmur only, of variable loudness, is heard at the pulmonary area. This is not uncommon in infants and young children, who may later develop the characteristic murmur (Gilchrist, 1945). Occasionally the continuous murmur is absent in adults in whom patency of the ductus is found subsequently at autopsy: in such cases the state of the pulmonary arteries and the presence of right ventricular hypertrophy may indicate that the pulmonary arterial pressure was much raised in life (Holman, 1925; Keys and Shapiro, 1943 (Case 3); Chapman, 1944; Douglas et al., 1947; Ulrich, 1947). As a result, the pressure gradient between the aorta and the pulmonary artery may be so diminished that the blood flow along the ductus is insufficient to set up a continuous murmur. In extreme examples the pressure in the pulmonary artery may exceed that in the aorta, causing a reversal of the usual left to right shunt (Johnson et al., 1950; Campbell and Hudson, 1951; Dammann et al., 1953). Three cases of patent ductus arteriosus complicated by severe pulmonary hypertension are presented here. The diagnosis was made in each on cardiac catheterization. In two, pulmonary hypertension caused reversal of the shunt; in the third the shunt was not reversed, but there was, in addition, coarctation of the aorta.