Abstract
We describe an aortic arch anomaly consisting of the origin of the left subclavian artery as the fourth branch and the right subclavian artery as the first branch off the aortic arch with crisscrossing of these two arteries anterior to the trachea without clinical consequences. This anomaly, to our knowledge, has not been reported previously.
Anomalous origin of one or more arteries from the aortic arch (AA) is frequent. Liechty and associates (1) studied 1000 adult cadavers and found “departures from the anatomic norm” in 350 cases (35%). Karacan and colleagues (2) studied 1000 adults by computed tomographic angiography and found “variations from the norm in aortic arch branching patterns” in 208 cases (21%). Origin of the right subclavian artery (RSA) from the fourth branch of the AA with coursing to the right arm posterior to the AA is a relatively common AA anomaly. Origin of the RSA as the fourth AA branch, however, combined with origin of the left subclavian artery (LSA) as the first branch of the AA with crisscrossing posterior to the AA must be an extremely rare anomaly.
CASE DESCRIPTION
A 69-year-old hypertensive, diabetic, and obese (body mass index 39 kg/m2) woman had cardiac arrest outside the hospital the day of death. Forty days earlier, she had a debilitating stroke. Necropsy disclosed no grossly visible myocardial lesions and minimally narrowed coronary arteries. Examination of the AA disclosed the LSA to be the first branch and the RSA to be the fourth branch of the AA, and both coursed posterior to the AA and anterior to the trachea. The RSA coursed posterior to the LSA, and both coursed posterior to the common carotid arteries. The lumen of all four arteries arising from the AA were wide open (Figure).
Figure.
The origin of the arteries from the aortic arch. LCCA indicates left common carotid artery; LSA, left subclavian artery; RCCA, right common carotid artery; RSA, right subclavian artery.
DISCUSSION
We have found no example of the anomaly described herein in any previously published report.
References
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