Ann Thorac Surg 2006;82:e19-e21
© 2006 The Society of Thoracic Surgeons
How to do it
The "Hinge-Twist" Technique for Anomalous Origin of the Left Coronary Artery
Leo Lopez, MD*,
Laura Mercer-Rosa, MD,
Evan M. Zahn, MD,
Nolan R. Altman, MD,
Renato Dubois, MD,
Redmond P. Burke, MD
The Congenital Heart Institute at Miami Children's Hospital, Miami, Florida
Accepted for publication May 4, 2006.
* Address correspondence to Dr Lopez, Miami Children's Hospital, 3200 SW 60th Ct, Suite 104, Miami, FL 33155. (Email: llmd{at}llmd.net).
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Abstract
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A murmur was heard in an asymptomatic boy (age 4), and transthoracic echocardiography revealed anomalous origin of the left main coronary artery (LMCA) from the right sinus of Valsalva (age 6). Confirmed by catheterization and computed tomographic angiography (age 10), the LMCA followed a short interarterial course between the aorta and main pulmonary artery before supplying the anterior descending and circumflex coronary arteries. An intramural segment was not clearly seen. Results of stress testing were normal. Because sudden death was a concern, the patient underwent surgery at age 11. The "hinge-twist" technique was utilized in the absence of an intramural component or ostial stenosis in an effort to avoid the long-term complications of coronary reimplantation, ostial patching, or bypass grafting.
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Introduction
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Sudden death may be the first manifestation of anomalous left coronary artery origin from the right sinus of Valsalva. Although an intramural course is common, other variants include coronary ostial stenosis, acute angulation of the coronary origin, and an intramyocardial course. The "hinge-twist" surgical technique may be useful when there is no intramural component or ostial stenosis and may avoid the long-term complications of coronary reimplantation, ostial patching, or bypass grafting.
A murmur was heard in an asymptomatic 4-year-old boy. At age 6, transthoracic echocardiography revealed anomalous origin of the left main coronary artery (LMCA) from the right sinus of Valsalva. Catheterization and computed tomographic angiography (CTA) at age 10 confirmed that the LMCA followed a short interarterial course between the aorta and main pulmonary artery (MPA) before supplying the anterior descending and circumflex coronary arteries (Fig 1A). An intramural segment was not clearly seen. Results of stress testing were normal. Because sudden death was a concern, the patient underwent surgery at age 11.
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Fig 1. (A) Preoperative computed tomography (CT) scan shows origin of the left coronary artery from the right sinus of Valsalva with an interarterial course (*) between the great arteries. (B) Postoperative CT scan shows normal origin and course of the left coronary artery (*) without kinking or stenosis. (Ao = aorta; RV = right ventricle.)
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Technique
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The original surgical goal involved posterior repositioning versus unroofing of the LMCA to relieve acute angulation of its origin and eliminate possible compression between the great arteries. After median sternotomy and bicaval–aortic cannulation, the heart was cooled, the aorta cross-clamped, and cardioplegia instilled every 20 minutes.
The ascending aorta was transected above the sinotubular junction and the coronary anatomy inspected. The right coronary artery (RCA) had a normal origin. The LMCA originated separately from the right sinus of Valsalva with an acute angle of origin and a posterior course behind the MPA. The ostium was adjacent to the intercoronary commissure, and the aortic valve was multiply fenestrated at its insertion into this commissure. The LMCA did not follow an intramural course, so unroofing was not possible. Explantation of the LMCA ostial button to the leftward posterior sinus was considered, but its proximity to the fenestrated commissure might require aortic valve resuspension with consequent aortic regurgitation.
Based on experience with creating neoaortic flaps for coronary transfers in the arterial switch procedure [1], we undertook a "hinge" sinoplasty approach by inserting a triangular pericardial patch into the sinus between the LMCA and RCA ostia and reorienting the LMCA origin posteriorly away from the MPA in a "hinge" maneuver (Fig 2A, B). The "hinge" effect was enhanced by a "twist" maneuver with a 30° counterclockwise rotation of the distal aortic clamp so that distal aortic recoil after anastomosis would torque the proximal aorta and the LMCA origin posteriorly. To prevent size mismatch, an identical triangular pericardial patch was inserted into the anterior ascending aortic wall (Fig 2A, C).
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Fig 2. (A) Diagram of "hinge-twist" technique. (B) Transected aorta with a triangular pericardial patch creates a "hinge" next to the anomalous left coronary artery ostium (*). (C) Triangular pericardial patch in the ascending aorta to match the proximal aortic circumference and counter-clockwise rotation ("twist") of the distal aorta to the right before aortic anastomosis. (Ao = aorta; AoV = aortic valve; LMCA = left main coronary artery.)
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Postoperative transesophageal echocardiography revealed a more posterior LMCA with a perpendicular angle of origin and no compression by the MPA. There was no turbulence along the LMCA nor was there aortic insufficiency or stenosis. Myocardial function was normal.
The patient was discharged on postoperative day 7. Follow-up CTA revealed separate and normal appearing coronary ostia without ectasia or stenoses (Fig 1B). Sixteen months later, the patient remains active and asymptomatic with a normal physical examination and echocardiogram.
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Comment
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In anomalous origin of a coronary artery from the opposite sinus of Valsalva, the coronary course between the aorta and MPA may be intramural (within the aortic wall and between the great arteries) or intramyocardial (within the sulcus between the great arteries) [2]. This is a common isolated congenital coronary anomaly associated with myocardial ischemia and sudden death during childhood [2, 3], although the mechanisms are unclear. Possible causes include compression between the great vessels because of increased aortic size and wall tension during periods of systemic hypertension such as exercise, flow restriction secondary to acute angulation of the origin (also exacerbated by aortic dilation), and ostial stenosis [2, 4].
Patients usually have normal results from electrocardiograms and stress tests. Diagnosis is made by echocardiography and supplemented by catheterization, magnetic resonance imaging, or multislice CTA; the latter two are less invasive and more informative about the relationship between the LMCA and great vessels [5].
Because sudden death may be the first manifestation, the indications for surgery have evolved to address this risk in asymptomatic patients [6]. Many suggest that all intramural coronary arteries should be repaired [2, 6]. For asymptomatic children, surgery is usually performed after age 10, since the risk of sudden death is low before adolescence.
A variety of techniques to address anomalous coronary arteries have been used with limited success [2, 4, 6]:
- 1 reimplantation, which may result in neo-ostial stenosis and is not useful for intramural coronary arteries;
- 2 unroofing (when there is a significant intramural course), which may disrupt aortic valve function at the intercoronary commissure;
- 3 bypass grafting with the saphenous vein or internal mammary artery, which is useful for ostial stenosis but is limited by finite durability of bypass grafts and potential for competitive flow from the anomalous coronary artery; and
- 4 sphincteroplasty of the coronary ostium for ostial stenosis, which may result in recurrent stenosis and persistent compression.
In the "hinge-twist" technique, the proximal LMCA is reoriented and "rotated" out of the area of compression between the great vessels by using a pericardial patch in the sinus of Valsalva. This is effective in anomalous coronary arteries without ostial stenosis or an intramural course that are not candidates for sphincteroplasty or unroofing. It also reduces the risk of neo-ostial stenosis and kinking associated with reimplantation and of graft failure with bypass grafting. The effect on valve function with this technique's alteration of aortic root architecture is not known, however, and long-term follow-up must bear this in mind.
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References
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- Chiu IS, Chou TF, Lin SF, Wu MH, Wang JK, Chu SH. Utilization of the aortic flap above the facing commissure in arterial switch operations J Card Surg 1996;11:187-191.[Medline]
- Frommelt PC, Frommelt MA. Congenital coronary artery anomalies Pediatr Clin North Am 2004;51:1273-1288.[Medline]
- Wilkins CE, Betancourt B, Mathur VS, Massumi A, De Castro C, Garcia E, Hall RJ. Coronary artery anomaliesa review of more than 10,000 patients from the Clayton Cardiovascular Laboratory. Tex Heart Inst J 1988;15:166-173.[Medline]
- Romp RL, Herlong JR, Landolfo CK, et al. Outcome of unroofing procedure for repair of anomalous aortic origin of left or right coronary artery Ann Thorac Sur 2003;76:589-595.
- Schmitt R, Froehner S, Brunn J, et al. Congenital anomalies of the coronary arteriesimaging with contrast-enhanced, multidetector computed tomography. Eur Radiol 2005;15:1110-1121.[Medline]
- Frommelt PC, Frommelt MA, Tweddell JS, Jaquiss RD. Prospective echocardiographic diagnosis and surgical repair of anomalous origin of a coronary artery from the opposite sinus of Valsalva with an interarterial course J Am Coll Cardiol 2003;42:155-157.[Free Full Text]
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Abstract
Introduction
