Coronary arteries often follow a subepicardial trajectory, penetrating the myocardium only near their conclusion. Occasionally, a portion of the epicardial artery may have an intramural trajectory, commonly termed as a myocardial bridge. The left anterior descending (LAD) artery is most likely to have an intramyocardial course compared to other coronary arteries (1). 

In a completed study, an intramyocardial LAD artery was present in 293 patients (21.7 percent). The prevalence was 20.2 percent (51/253) in females and 22.1 percent (242/1096) in males (2). 

The technique of locating the intramyocardial LAD artery by opening the artery at the apex of the left ventricle, where the artery is easily visible has been described in literature. A 1 mm coronary probe is passed proximally, allowing the mid-portion of the LAD artery to be identified, and the myocardium overlying the artery is incised until the artery is safely identified (3).  

In this case, the same technique was utilized. The LAD artery could initially be visualized only at the apex of the left ventricle. The intramyocardial LAD artery was not diagnosed preoperatively during conventional coronary angiography and was identified as an intraoperative finding. Two 6-0 polypropylene sutures were placed on either side of the visible distal LAD artery. A small opening was made in the artery to accommodate a 1 mm coronary probe, which was passed proximally. Over the coronary probe, the LAD artery was opened after incising the overlying epicardial fat and myocardial bridge. Once the artery was identified and opened, the left internal mammary artery was anastomosed, and the distal opening was closed with a patch from the remaining left internal mammary tissue. 

References

1. Çiçek D, Kalay N, Müderrisoğlu H. Incidence, clinical characteristics, and 4-year follow-up of patients with isolated myocardial bridge: a retrospective, single-center, epidemiologic, coronary arteriographic follow-up study in southern Turkey. Cardiovascular Revascularization Medicine. 2011;12(1):25–8.
2. Vanker EA, Ajayi NO, Lazarus L, Satyapal KS. The intramyocardial left anterior descending artery: Prevalence and surgical considerations in coronary artery bypass grafting. South African Journal of Surgery. 2014;52(1):18–21.
3. Robinson G. Location of the proximal left anterior descending coronary artery. The Annals of thoracic surgery. 1973;15(3):299–300.

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