Ann Thorac Surg 1997;64:1194-1196
© 1997 The Society of Thoracic Surgeons
How To Do It
Ventriculotomy Repair During Revascularization of Intracavitary Anterior Descending Coronary Arteries
Eduardo A. Tovar, MD,
Alan Borsari, MD,
Daniel W. Landa, MD,
Paul B. Weinstein, MD,
Alan B. Gazzaniga, MD
Departments of Cardiothoracic Surgery and Cardiology, St. Jude Medical Center, Fullerton, and the University of California, Irvine Medical Center, Orange, California
Accepted for publication April 28, 1997.
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Abstract
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Optimal revascularization of the rare variant anomolous intracavitary left anterior descending coronary artery requires, by definition, entrance into the right ventricular cavity. We present a simple method to repair the ventriculotomy without risk of obliterating the left anterior descending coronary artery, septal perforators, or diagonal branches.
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Introduction
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See also page 1196.
Since McAlpine [1] in 1975 first described the anomalous intracavitary course of the proximal left anterior descending coronary artery (LAD) into the right ventricle and the right coronary artery into the right atrium, there have been only three reports [2–4] to our knowledge that have addressed this clinical entity.
According to Polácek and Zechmeister [5], mammalian hearts can be classified depending on the depth of their coronary arteries and their main branches into three types: type A (hamster, squirrel, rat, guinea pig, and rabbit) in which the coronary arteries are entirely intramyocardial; type B (human, goat, sheep, dog, cat, and macaque) in which the coronary arteries are predominantly subepicardial but exhibit frequent myocardial bridging; and type C (horse, cow, and pig) in which the coronary arteries are entirely subepicardial. Among humans, the LADs may be subdivided according to their position in the anterior-posterior plane into aerial (above the surface of the heart), subepicardial, intramyocardial, and intracavitary (a stretch of the artery penetrates the cavity of the right ventricle) [1–3]. Most commonly the LAD lies in a subepicardial position; however, its proximal third is frequently covered by muscle fibers that are direct extensions of the pulmonary infundibular myocardium [6, 7].
In coronary artery bypass grafting the ideal site to construct the distal anastomosis is immediately beyond the obstructive lesion. This allows antegrade flow in the bypassed vessel and use of the largest possible diameter of the designated artery [2]. As a result, not infrequently an intramural segment of the LAD has to be exposed. The main concern during this surgical step is inadvertent entrance into the right ventricle. Careful dissection of the artery will rarely result in this complication. However, surgeons who frequently engage in the search for an intramyocardial LAD may eventually find an intracavitary artery.
Repair of a right ventriculotomy that has occurred incidentally (intracavitary LAD) or accidentally (intramural LAD) has traditionally been performed with buttressed horizontal mattress sutures passed beneath the coronary artery similar to those used for traumatic ventricular injuries adjacent to the LAD (Fig 1
) [2, 7, 8]. This method may cause obstruction of the LAD [2], septal perforators, or diagonal branches (Fig 2). We describe a simple alternative to this technique that avoids such complications.
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Fig 1. . Classic repair of right ventricular laceration adjacent to the left anterior descending coronary artery in a porcine heart.
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Fig 2. . Horizontal pledgetted mattress sutures can lacerate or occlude septal perforators or diagonal branches (arrow shows suture traversing under the left anterior descending coronary artery in a porcine heart).
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Technique
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After exposure of a suitable portion of the proximal LAD in which the right ventricle has been entered, an arteriotomy is performed in preparation for the distal anastomosis. At this point, the right ventriculotomy is repaired using horizontal mattress sutures of 5-0 or 6-0 polypropylene that are placed parallel to the ventricular incision. The free edge of the right ventricle is then approximated to the ventricular septum (Fig 3). The sutures are bolstered with a portion of saphenous vein, pericardium, or Teflon felt pledgets. The artery is probed to establish its complete patency and the anastomosis is then completed in the usual manner.
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Fig 3. . Horizontal pledgetted mattress sutures used to approximate the free edge of the right ventricle (RV) to the interventricular septum (IVS).LV = left ventricle.)
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Comment
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It is not possible to diagnose an intracavitary course of an LAD preoperatively. Angiographically there are only clues that may differentiate superficial (aerial and subepicardial) from deep (intramural and intracavitary) stretches of the LAD. The superficial segments are usually tortuous. Straight stretches, although they may be superficial, are often deep. Early in its descending course the deep LAD dives in an acute angle then remains straight and, when it emerges distally, adopts a serpentine course (Fig 4) [2, 8]. The methods used to expose an intracavitary segment of the LAD are similar to those used for an intramural stretch of the artery. In 1976, Gandjbakhch and Cabrol [9] described four techniques to locate intramyocardial portions of the LAD. They include the retrograde dissection of the distal LAD, the retrograde dissection of a diagonal branch, and the retrograde passage of a probe inserted through a distal arteriotomy.
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Fig 4. . Angiographic appearance of an intracavitary left anterior descending coronary artery. The straight stretch (between the two arrows) represents the intracavitary portion followed by the superficial serpentine course.
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We have encountered two instances in which the LAD had an intracavitary stretch among our last 1,000 cases of coronary artery bypass grafting. Our incidence is similar to the reported incidence of anomalous intracavitary LAD of 0.2% to 0.3% [1, 2]. In this same group of patients, twice we inadvertently entered the right ventricle while exposing an intramural portion of an LAD. In all 4 cases we used the described technique to repair the right ventricle without experiencing complications.
While reviewing the literature in preparation for this communication we came across a description by Barner [10] of what we believe is the method here described. If that is the case, our experience is a validation that the technique is sound and reliable.
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Acknowledgments
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We express our appreciation to Jean L. Burnette for her invaluable editorial assistance in preparing the manuscript and Carol Bondurant, St. Jude Medical Center Library, for data collection.
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References
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- McAlpine WA, ed. Heart and coronary arteries. An anatomical atlas for clinical diagnosis, radiological investigation, and surgical treatment. New York: Springer-Verlag, 1975:186–7.
- Ochsner JL, Mills NL. Surgical management of diseased intracavitary coronary arteries. Ann Thorac Surg 1984;38:356–62.[Abstract]
- Ochsner JL, Mills NL, eds. Coronary artery surgery. Philadelphia: Lea & Febiger, 1978:26–32.
- Kolodziej AW, Lobo FV, Walley VM. Intra-atrial course of the right coronary artery and its branches. Can J Cardiol 1994;10:263–7.[Medline]
- Polácek P, Zechmeister A, eds. The occurrence and significance of myocardial bridges and loops on coronary arteries. Vol 1. Brno: University J. E. Purkyne Medical Faculty, 1968.
- Angelini P, Trivellato M, Donis J, Leachman RD. Myocardial bridges: a review. Prog Cardiovasc Dis 1983;26:75–88.[Medline]
- Iversen S, Hake U, Mayer E, Erbel R, Diefenbach C, Oelert H. Surgical treatment of myocardial bridging causing coronary artery obstruction. Scand J Thorac Cardiovasc Surg 1992;26:107–11.[Medline]
- Oz MC, Cooper MM, Hickey TJ, Rose EA. Exposure of the intramyocardial left anterior descending artery. Ann Thorac Surg 1994;58:1194–5.[Abstract]
- Gandjbakhch I, Cabrol C. Techniques de découverte d'une artère interventriculaire "masquée" en chirurgie coronarienne. Nouv Presse Med 1976;40:2713–4.
- Barner HB. Discussion of: Ochsner JL, Mills NL. Surgical management of diseased intracavitary coronary arteries. Ann Thorac Surg 1984;38:361.
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Abstract
Introduction
