Patent ductus arteriosus in adult patients with aortic valvular disease: the importance of routine screening for a left-to-right shunt at cardiac catheterization

Intracardiac shunts

Unsuspected intracardiac shunts can be a cause of acute deterioration in critically ill patients. Shunts can be acquired or congenital conditions that become symptomatic only with changed physiologic conditions. Transesophageal echocardiography is an excellent tool for the diagnosis of intracardiac shunts.

Combined aortic valve replacement and closure of patent ductus arteriosus in the elderly

Two cases of patent ductus arteriosus (PDA) and aortic stenosis are presented. Both were diagnosed at routine cardiac catheterization and significant aortic gradient was concomitantly encountered. The first patient had subacute bacterial endocarditis due to B. cereus infection. Eventually it was proven to be localized on the PDA on the pulmonary artery side. Both patients underwent closure of PDA through endopulmonary closure and aortic valve replacement. Postoperative courses were uneventful. These cases demonstrated the technically easy closure of the PDA in the elderly. The literature has documented only six cases including our two cases.

Congenital aortic stenosis and patent ductus arteriosus in the adult

Concurrent aortic stenosis and patent ductus arteriosus are not infrequent in children but are rare in adults. An adult case is described with diagnosis by cardiac catheterization and magnetic resonance imaging and with management by combined aortic valve replacement and patent ductus ligation. Review of the English-language literature produced only 8 such cases in adults, 2 of which were managed by a single-stage operation. Successful diagnosis in the adult requires careful observation at cardiac catheterization, and simultaneous valve replacement and ductus ligation may be a useful option in patient management.

Diagnosis of unexpected atrial septal defect by inspired hydrogen appearance time in adult patients referred for cardiac catheterization

Atrial septal defects may have clinical consequences regardless of their size. We evaluated the incidence of clinically unsuspected atrial septal defects in 4,411 consecutive adult patients referred for cardiac catheterization by the previously validated method of inspired hydrogen appearance time. Oximetry was performed only when an abnormally short inspired hydrogen appearance time was measured. Seventy-five patients (1.7%) were discovered to have a left-to-right shunt by this method. The shunting was at the atrial level in 65 patients. Thirty-five of these patients (0.8% of all catheterizations) were not suspected of having any form of congenital heart disease by history, physical examination, chest X-ray, EKG, or echocardiogram. In 19 cases there was no significant oxygen step-up and the diagnosis would have been missed by oximetry. The atrial septum was explored during open heart surgery in 7 patients. Atrial septal defects were detected and closed in all. Four patients had the finding confirmed by echocardiography after the catheterization. Small atrial septal defects are frequently not detected by clinical evaluation, noninvasive testing, or oximetry and are easily detected by the rapid, safe, and accurate method of inspired hydrogen appearance time.

Diagnosis of patent ductus arteriosus by serendipity in the adult

Seven patients with patent ductus arteriosus (PDA) were seen in our adult echocardiography laboratory. In five of seven patients the diagnosis was made on color Doppler when it was not suspected clinically. The diagnosis became apparent because of a turbulent retrograde jet seen on color Doppler in the main pulmonary artery. One of the patients had known congenital heart disease and heart surgery in the past, and the diagnosis of PDA was missed both on catheterization and in the operating room. PDA may be unsuspected in adult patients and may be missed by techniques other than color Doppler echocardiography. The striking findings on color Doppler may help to make this important diagnosis in such patients.

Unsuspected left-to-right shunt: is routine use of hydrogen platinum electrode system indicated in shunt detection?

Unsuspected left-to-right shunt was found in 6 of 1,500 adult patients undergoing diagnostic cardiac catheterization. In 3 patients were found unsuspected secundum atrial septal defects (1 associated with mitral stenosis and 2 with coronary artery disease). In 3 patients, unsuspected partial anomalous pulmonary venous drainage was found (1 associated with aortic valve disease and 2 with severe coronary artery disease). It is concluded that the incidence of unsuspected left-to-right shunt diagnosed during routine cardiac catheterization is very low. Careful physical examination and the application of conventional techniques during cardiac catheterization should suggest the possibility of such a shunt. Hydrogen platinum electrode system (HPES) should be reserved for patients in whom the right heart catheter takes an abnormal course or when the pulmonary artery oxygen saturation is high and the arteriovenous oxygen difference is small.