Comment on: Dual LAD with anomalous origin of long LAD from right coronary sinus: A variant of type VI LAD.

Sir,

We read with great interest the article by Vohra et al. published in May 2016 issue of IJRI.[1] We congratulate the authors on reporting an extremely rare variant of dual left anterior descending artery (LAD). We would also like to report an interesting variant of dual LAD, which we recently diagnosed in a patient.

A 50-year-old gentleman was referred to our department for computed tomography (CT) coronary angiography with complaints of pain on the left side of the chest and cold sweats since 4 days. CT coronary angiography, done on a 64-slice CT (Somatom Sensation-64, Erlangen, Germany), showed evidence of dual LAD. The short LAD was arising from the left main coronary artery and coursing in the proximal anterior interventricular groove and terminated after giving a large septal and one large diagonal branch. The long LAD was found arising from the right coronary sinus in close proximity to the right coronary artery (RCA) ostium [Video 1]. It showed epicardial course between the aortic root and right ventricular outflow tract (RVOT) and reached the mid anterior interventricular groove [Figures 1 and 2]. No significant disease was noted in either LAD; however, severe plaque-induced narrowing was found in the large diagonal arising from short LAD.

Figure 1

Oblique maximum intensity projection (MIP) CT Coronary Angiography image shows the short LAD (bold arrow) arising from the left main coronary artery and terminating in the proximal anterior interventricular groove. The long LAD (open arrow) arising from the right coronary sinus adjacent to the RCA ostium and coursing between the RVOT and aortic root

Figure 2

Three dimensional volume rendered (VRT) CT Coronary Angiography image shows the long LAD (open arrow) arising from the right coronary sinus and entering the mid anterior interventricular groove. The short LAD from left main coronary artery is terminating (bold arrow) after giving large diagonal and septal branches.

Dual LAD were first classified into four types by Spindola-Franco et al.,[2] however, many other variants of dual LAD have been added since then. A recent article by Celik et al. mentioned ten types of dual LAD.[3] Our case does not fit exactly in any of the described types, however, it is similar to the one described as type VI LAD which was reported by Maroney and Klein,[4] in which the long LAD arises from the RCA and shows an interarterial course between the aortic root and RVOT. However, our case is different from the classic type VI LAD as in our case the long LAD was arising from the right coronary sinus and not from the RCA, as noted in their case. Hence, this variant of LAD can be classified as type VIa LAD where the long LAD arises from the right coronary sinus and shows an interarterial course between the aortic root and RVOT. We could find only one previously described case of similar type of dual LAD.[5]

Our case adds to the database of ever increasing types of dual LAD and emphasizes the need for carefully outlining the course and number of LAD on CT coronary angiograms so that significant anomalies are not missed.

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Conflicts of interest

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