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J Thorac Cardiovasc Surg 1998;116:1078-1080
© 1998 Mosby, Inc.
BRIEF COMMUNICATIONS |
New Delhi, India
J Thorac Cardiovasc Surg 1998;116:1078-80
Received for publication July 24, 1998. Accepted for publication July 30, 1998. Address for reprints: K.S. Iyer, MCh, Senior Consultant and In-Charge, Paediatric and Congenital Heart Surgery, Escorts Heart Institute and Research Center, Okhla Road, New Delhi 110025, India
Congenital coronary artery abnormalities are rare, occurring in only 1% to 2% of the population. Anomalous origin of either the left coronary artery (LCA) or right coronary artery (RCA) from the aorta is recognized in approximately 0.3% of the adults having arteriograms for diagnosis of coronary heart disease. Anomalous origin of a coronary artery from the pulmonary artery (ALCAPA) is a rare congenital anomaly, with a prevalence of 2.5 to 5.0 per 100,000 live births.
1
In a large series reported by Fernandes and colleagues, 2 the LCA was involved in 56 to 60 cases; the RCA arose from the pulmonary artery in 2 patients, and the circumflex or left artrial branch arose from the pulmonary artery (PA) in 2 patients. Isolated anomalous left anterior descending (LAD) coronary artery arising from PA is a rare anomaly. So far, we have been able to locate only one case report of successful surgical correction. 3 Here we report the diagnosis and successful surgical correction of another such case.
Clinical summary.
A 7-year-old girl was referred to this hospital with complaints of dyspnea on exertion of New York Heart Association class III severity of 1-year duration. Physical examination was not contributory. The electrocardiogram revealed significant elevation of S-T segments in precordial leads. Chest radiographs showed mild left ventricular type of cardiomegaly.
Cross-sectional echocardiography revealed a dilated and tortuous right coronary artery arising from the right sinus. The left sinus gave origin to the circumflex coronary artery although the LAD took origin from the PA with retrograde flow into it on color Doppler echocardiography (Fig. 1).
Cardiac catheterization did not reveal a left-to-right shunt into the PA, and PA pressures were within normal limits. Selective coronary angiography confirmed the echocardiographic suspicion of isolated anomalous LAD arising from the PA (Fig 2, Aand B). Operative technique.
The heart was cannulated with a distal ascending aortic cannula and bicaval venous cannulas. Cardiopulmonary bypass was instituted, and the patient was cooled to 28°C. The aorta was crossclamped, and cold blood cardioplegic solution was infused at a pressure of 80 mm Hg for 3 minutes to achieve cardiac arrest. At the same time, the PA was transected, and cold blood cardioplegic solution was infused directly into the LAD ostium. The orifice of the anomalous LAD was excised along with a wide cuff of PA. The LAD was then carefully mobilized for about 1 cm length. A 4-mm hole was punched in the anterolateral wall of the ascending aorta adjacent to the PA, after distending the aortic root with cardioplegic solution to avoid injury to the aortic valve. The cuff of PA with the anomalous LAD was pulled up to this opening without any tension, and the anastomosis was performed with a running 7-0 Prolene suture (Ethicon, Inc, Somerville, NJ). The defect in the PA where the LAD button had been removed was covered with a pericardial patch, and PA continuity was restored. Intraoperative transesophageal echocardiography after cardiopulmonary bypass showed a well-opened well-filled LAD from the ascending aorta and absence of any right ventricular outflow tract obstruction.
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Discussion.
Most coronary artery malformations are anomalies of the site of origin, 71% in the necropsy series of Van Praagh.4 In 26% of cases, the LCA arose from the PA. We could find only one published successful surgically corrected case of LAD arising from the PA with normal origin from the aorta of RCA and circumflex arteries.3
Three theories have been put forward to explain the origin of a coronary artery from the pulmonary trunk. 5 The first 2 theories relate to embryologic division of the truncus arteriosus. Assuming that the coronary arteries arise as 2 endothelial buds, displacement of the site of origin of 1 or both coronary artery buds could assign either or both coronary arteries to that portion of the truncus arteriosus destined to become the PA. Alternatively, faulty division of the truncus by the developing truncal septum could incorporate one or both normally located coronary artery buds into the PA. The higher incidence of anomalous origin of the LCA from the pulmonary trunk has been explained by the proximity of the left aortic sinus to the truncal septum. A relatively small displacement of the LCA anlage would cause the LCA ostium to lie within the PA. These theories presuppose that human coronary arteries may not appear until division of the truncus is complete or nearly so. The mentioned theories also fail to explain cases of a third (accessory) coronary artery or the presence of only one branch of the LCA (eg, LAD) from the pulmonary trunk or why the relative sizes of the PA, aorta, and their valves are not altered by the presumed displacement of the truncal septum. An alternative "involution and persistence" theory postulates that there are originally 6 coronary artery anlagen, together with abnormal involution of one or more of the normally persistent aortic coronary anlagen.Infants with collateral vessels have the so-called adult form and may survive infancy but usually show signs of myocardial ischemia later in childhood. Those infants without collateral vessels have the infantile type and usually die within the first few months of life. Because patients with coronary artery abnormalities frequently lack direct physical findings, a high level of clinical suspicion is imperative for accurate and timely diagnosis. The typical electrocardiographic finding is an anterolateral myocardial infarction pattern in the setting of dysfunctional left ventricle. Although angiography is a most sensitive technique for definitive diagnosis, anomalous origin of a coronary artery can be reliably diagnosed by 2-dimensional and color Doppler echocardiography. 6Surgical establishment of a dual coronary artery system is the treatment of choice for patients with ALCPA. 7 Surgical procedures that result in a dual coronary system include intrapulmonary tunnel repair, coronary artery reimplantation, left subclavian artery–LCA anastomosis, and saphenous vein interposition. The latter 2 approaches may be associated with vessel kinking and graft degeneration and have a higher reported mortality rate. The tunnel repair has the risk of tunnel occlusion and acquired supravalvular pulmonary stenosis. 7 Many authors have recently concluded that coronary artery reimplantation is the procedure of choice because it can be performed safely in patients under 1 year of age and offers good arterial patency rates. 7 Experience with the arterial switch procedure for transposition of the great arteries has resulted in improved surgical results for reimplantation. However, the origin of the ALCAPA from a left lateral sinus may make implantation technically difficult, and the tunnel procedure then offers an alternative solution. For infants with ALCAPA, therefore, we recommend early anatomic repair by direct aortic implantation to establish a 2-coronary artery system whenever this is anatomically feasible.
Late outcome depends on the recovery of ventricular and valvular function. Improvement of left ventricular function after successful re-establishment of a dual coronary artery system has been clearly documented.
References
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