Cardiovascular Abnormalities Following Surgery for Left-to-Right Shunts

Abstract

Seventy-two patients with left-to-right shunts were studied an average of 5 years after operation. Persistent residual shunts occurred in 24 of the 72 patients and were unsuspected clinically in 11. While significant residual shunts were usually suspected in the group with ventricular septal defects (VSD), residual shunts in the group with atrial septal defects (ASD) were frequently unsuspected. Abnormalities in pulmonary vascular reactivity as determined by excessive responses to hypoxia or exercise, or both, were noted in a significant number of cases of VSD and patent ductus arteriosus. Such unusual reactivity was not seen as frequently in the ASD group. Low cardiac output responses to exercise were noted in nearly half of the patients. These studies illustrate the importance of long-term follow-up hemodynamic studies on postoperative patients with left-to-right shunts and indicate the necessity for exercise and hypoxia studies in addition to resting observations.