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CARDIOVASCULAR ANESTHESIOLOGY

Echocardiographic Features of Pulmonary Atresia with Intact Ventricular Septum

Thomas M. Burch, MD^*, K. Annette Mizuguchi, MD, PhD, Mark C. Wesley, MD^*, Tara M. Swanson, MD, and James A. DiNardo, MD^*

From the *Department of Anesthesiology, Children’s Hospital; Brigham and Women’s Hospital; and Department of Cardiology, Children’s Hospital, Boston, Massachusetts.

Address correspondence and reprint requests to Thomas M. Burch, MD, Pediatric Cardiac Anesthesiology Fellow, Department of Anesthesiology, Children’s Hospital, Boston, 180 Brookline Ave # 536, Boston, MA 02215. Address e-mail to tburch333{at}yahoo.com.

A 36 wk, 2.1 kg girl prenatally diagnosed by echocardiography with pulmonary atresia with intact ventricular septum, (PA/IVS) and coronary sinusoids was started on a prostaglandin E₁ infusion immediately after birth. Postnatally, a transthoracic echocardiogram revealed PA/IVS, severe tricuspid and right ventricular (RV) hypoplasia, RV hypertrophy, RV to coronary artery sinusoids, a secundum atrial septal defect with bidirectional flow, and a large patent ductus arteriosus as the sole source of pulmonary blood flow. (Figs. 1 and 2 and Videos 1 and 2; please see video clips available at www.anesthesia-analgesia.org). Cardiac catheterization on day of life two revealed suprasystemic RV pressures, RV to coronary artery fistulae and ostial coronary stenoses (Fig. 1 and Video 2). In the intensive care unit on day of life 15, anemia and associated hypovolemia produced myocardial ischemia, which resolved after transfusion of packed red blood cells (Video 2). The patient was listed for cardiac transplantation (status 1A), and underwent cardiac transplantation at age 3 mo. Gross pathologic examination of the explanted heart revealed: PA/IVS with RV hypoplasia, tricuspid stenosis, RV hypertrophy, narrow coronary arteries, and areas of fibrosis consistent with myocardial infarction (Video Clip 3; please see video clip available at www.anesthesia-analgesia.org).

View larger version (59K): [in this window] [in a new window]   Figure 1. An anterior–posterior catheterization view (right ventriculogram) with the catheter located in the right ventricle is shown. Ao = aorta; RV = right ventricle.

View larger version (44K): [in this window] [in a new window]   Figure 2. Transthoracic four chamber view showing right ventricular hypoplasia and hypertrophy. A secundum atrial septal defect is also shown. Note no ventricular septal defect is seen. RA = right atrium; RV = right ventricle; LA = left ventricle; LV = left ventricle.

DISCUSSION

The incidence of PA/IVS is 4.5 per 100,000 live births.1 RV to coronary artery fistulae have been reported to occur in up to 68% of patients with PA/IVS.2 When there are RV to coronary artery fistulae in conjunction with severe obstruction of at least two major coronary arteries, left ventricular coronary perfusion is dependent on RV intracavitary pressure and RV-dependent coronary circulation (RVDCC) is said to exist. RVDCC may be present in as many as 34% of PA/IVS patients.2 In these patients, reduction in RV pressure, whether due to surgical decompression of the RV (RV outflow patch, pulmonary valvotomy, or tricuspid valvotomy and tricuspid insufficiency) or reduced RV preload or contractility, results in decreased coronary blood flow and myocardial ischemia (Video clips 1–3).

In utero, lack of blood egress from the RV via the pulmonary valve or a ventricular septal defect results in varying degrees of tricuspid valve and RV hypoplasia. Despite low RV volumes, RV pressure is high due to this lack of RV decompression. These elevated RV pressures result in the development of coronary anomalies. Although left ventricular coronary venous drainage is to the right atrium through the coronary sinus, much of the RV coronary venous drainage is into the RV via the thebesian veins. Elevated RV pressures are believed to force blood retrograde through the thebesian veins creating both coronary sinusoids (enlarged thebesian veins) and fistulae (enlarged thebesian veins that communicate directly with the epicardial coronary arteries).3 High pressure retrograde flow may also cause endothelial damage and explain the occurrence of epicardial coronary stenoses; additionally or alternatively primary coronary artery abnormalities may play a role.

Patients with PA/IVS without RVDCC are candidates for a two-ventricle repair after establishment of antegrade pulmonary blood flow and sufficient growth of the tricuspid valve and RV over time. Patients with PA/IVS and RVDCC must undergo either cardiac transplantation or staged single ventricle palliation to the Fontan procedure (total cavopulmonary connection), since they are not candidates for any procedure that decompresses the RV.2

Echocardiography is essential in the evaluation and early treatment of these patients. Small right-sided structures should prompt the echocardiographer to use color flow Doppler to exclude PA/IVS by finding antegrade pulmonary blood flow and/or a ventricular septal defect. Coronary sinusoids are usually visible as are the coronary artery ostia. Although retrograde coronary blood flow may be visualized echocardiographically, cardiac catheterization is always needed to delineate the coronary anatomy, the location of stenosis, and the sources of epicardial coronary blood flow.

Z scores are used to compare the relative two-dimensional size of a child’s cardiac structures to the normal population mean for that structure. The Z score is a dimensionless index indicating how many standard deviations a particular measurement is above or below the population mean. For example, a valve with a Z score of –1 to +1 is considered of normal size, whereas a valve with a Z score <–2.5 is quite hypoplastic. Tricuspid valve hypoplasia is frequently present in PA/IVS and a tricuspid valve Z score <–2.5 in the setting of PA/IVS is associated with the presence of RVDCC.4 Pulmonary artery size is assessed, although they are usually normal in caliber. Patent ductus arteriosus-dependent pulmonary blood flow and a nonrestrictive interatrial septum should be confirmed by color flow Doppler. Shunting at the atrial level is bidirectional but primarily right to left. Nonrestrictive flow is essential, as oxygenated pulmonary venous blood shunts left to right, traverses the tricuspid valve and perfuses the myocardium via the RV-coronary fistulae. Doppler interrogation of a tricuspid regurgitant jet can be used to estimate RV systolic pressure.

Echocardiographic evaluation during cardiac transplantation can be accomplished with either TEE or epicardial imaging. In our opinion, the benefits of intraoperative TEE imaging were outweighed by the risks of respiratory and hemodynamic compromise from compression. During weaning from bypass, we used epicardial imaging for deairing and assessing ventricular systolic function. Echocardiography also may diagnose pulmonary venous obstruction, and early rejection [as indicated by grade 1 diastolic dysfunction (impaired relaxation)5].

Footnotes

Accepted for publication June 13, 2008.

Supported by the Department of Anesthesiology at Children’s Hospital Boston.

This article has supplementary material on the Web site: www.anesthesia-analgesia.org.

REFERENCES

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2. Guleserian KJ, Armsby LB, Thiagarajan RR, del Nido PJ, Mayer JE Jr. Natural history of pulmonary atresia with intact ventricular septum and right-ventricle-dependent coronary circulation managed by the single-ventricle approach. Ann Thorac Surg 2006;81:2250–7; discussion 8
3. Kutsche LM, Van Mierop LH. Pulmonary atresia with and without ventricular septal defect: a different etiology and pathogenesis for the atresia in the 2 types? Am J Cardiol 1983;51:932–5[Web of Science][Medline]
4. Satou GM, Perry SB, Gauvreau K, Geva T. Echocardiographic predictors of coronary artery pathology in pulmonary atresia with intact ventricular septum. Am J Cardiol 2000;85:1319–24[Web of Science][Medline]
5. Studeli R, Jung S, Mohacsi P, Perruchoud S, Castiglioni P, Wenaweser P, Heimbeck G, Feller M, Hullin R. Diastolic dysfunction in human cardiac allografts is related with reduced SERCA2a gene expression. Am J Transplant 2006;6:775–82[Web of Science][Medline]

This Article Full Text (PDF) Echo Loops Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Burch, T. M. Articles by DiNardo, J. A. Search for Related Content PubMed PubMed Citation Articles by Burch, T. M. Articles by DiNardo, J. A. Related Collections Cardiovascular Monitoring (Cardiac) Echo Rounds Video Clip Pediatrics