Prevalence of Anomalous Coronary Arteries in Pulmonary Atresia With Ventricular Septal Defect and Major Aortopulmonary Collaterals

To the Editor:

Pulmonary atresia (PA) with ventricular septal defect (VSD) and major aortopulmonary collaterals (MAPCA) is a member of the conotruncal defect family. These defects all originate from abnormal embryogenesis of the conotruncus at 27 to 37 days of fetal life. PA/VSD/MAPCA has many of the characteristic hallmarks of conotruncal defects, including a malalignment VSD and the most extreme disparity in septation of the conotruncus. The common embryogenesis results in many similarities across a wide range of anatomic malformations.

Anomalous coronary arteries are another hallmark of conotruncal defects. Tetralogy of Fallot has a 5% prevalence of anomalous coronaries, whereas truncus arteriosus is approximately 30%. The clinical implications of anomalous patterns can be profound, as documented for the left anterior descending coronary originating from the right coronary in tetralogy of Fallot.

PA/VSD/MAPCA is a relatively uncommon form of congenital heart defect, and advances in treatment have been shown by our group and others (1). However, the prevalence of coronary artery anomalies for PA/VSD/MAPCA has not been documented. The purpose of the present study was to evaluate the prevalence of anomalous coronary patterns in PA/VSD/MAPCA.

This study was approved by the Institutional Review Board of Stanford University. Sixty-four consecutive patients undergoing single-stage complete repair (2009 through 2012) were included. The intra-operative coronary artery patterns were documented based on the surface anatomy.

These intra-operative observations were compared to the pre-operative cardiac catheterization.

There were 38 female and 26 male subjects. Median age at surgery was 10.3 months (range: 5 days to 12.5 years) and median weight was 6.3 kg (range: 2.3 to 32 kg).

Forty-seven of the 64 patients (73%) had a normal coronary artery pattern identified intra-operatively, whereas 17 patients (27%) had an anomalous coronary artery pattern. There were 4 anomalous coronary patterns observed. The most frequently encountered anomalous course was a left anterior descending (LAD) originating from the right coronary (Fig. 1A), identified in 15% of patients. The other 3 anomalous patterns (Figs. 1B to 1D) were observed collectively in 11% of patients. One patient had an anomalous origin of the right coronary artery from the noncoronary sinus of Valsalva.

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Figure 1

Illustrations of the 4 Anomalous Coronary Artery Patterns

(A) Anomalous origin of the left anterior descending (LAD) originating from the right coronary artery (RCA). This was the most common anomalous pattern, accounting for 9 of 17 cases. (B) Anomalous origin of a coronary branch originating from the RCA and supplying the interventricular septum. There is also an LAD with a normal origin and course (dual LAD). (C) Anomalous origin of the RCA from the LAD. (D) Anomalous origin of a branch of the RCA originating from the LAD supplying the free wall of the right ventricle. There is also a separate RCA with a normal origin and course.

Cardiac catheterization corroborated the coronary artery pattern found intra-operatively in 58 of 64 (91%) cases. The 6 cases in which the cardiac catheterization did not correlate were all false negatives. Two of the false negatives had a dual LAD, 2 had a coronary branch to the right ventricular free wall from the LAD, and 1 had the entire right coronary originating from the LAD. The final false negative was the right coronary from the noncoronary sinus.

In addition to the anomalous coronary patterns, 3 patients had a pulmonary artery from a coronary and 2 patients had a MAPCA from a coronary artery.

This manuscript describes the coronary artery patterns in 64 consecutive patients undergoing repair of PA/VSD/MAPCA. Twenty-seven percent of the patients had an anomalous origin and course of their coronary arteries. The most frequently observed anomalous course was a LAD originating from the right coronary and accounted for 15% of all anomalous patterns.

This prevalence of coronary arterial anomalies in PA/VSD/MAPCA is at the high end of the spectrum compared with other forms of conotruncal defects.

There was a 91% correlation between the coronary artery patterns identified at surgery and the findings described by cardiac catheterization. The 9% of patients who were not correctly identified at catheterization were all false negatives. The specificity of cardiac catheterization was 100% and the sensitivity was 65%. Five of the 6 false negatives had 2 separate coronary ostia, emphasizing the need to exclude all 4 anomalous coronary patterns.

Recognition of coronary artery anomalies is important in PA/VSD/MAPCA due to the need for placement of a conduit from the right ventricle to the reconstructed pulmonary arteries. The surface anatomy of the coronary system is discernible at the time of the first surgical procedure, and this is why this is a requirement for inclusion in this study. The ability to see the coronary arterial pattern at first surgery allows safe placement of the proximal end of the conduit regardless of the presence or absence of anomalous coronaries. The surface anatomy is obscured in subsequent re-operations, and during these subsequent conduit changes, injury to coronary arteries can occur. In view of the relatively high prevalence of anomalous coronaries in PA/VSD/MAPCA, it is imperative to identify the coronary artery pattern prior to contemplating re-operations for conduit replacement.

In summary, this study has documented a 27% incidence of anomalous coronary arteries in patients with PA/VSD/MAPCA. This information is clinically important to avoid coronary injuries during conduit re-operations.

• American College of Cardiology Foundation