Dual Left Anterior Descending Coronary Artery With Origin of Short Left Anterior Descending Coronary Artery From Left Main Shaft — A Rare Coronary Anomaly

 Abstract: Dual left anterior descending (LAD) coronary artery with separate origin of the short LAD from the left main (LM) coronary artery is very rare and not reported in the literature. A 49-year-old male was admitted with history of mid-sternal chest pain at rest. He underwent coronary angiography, which showed normal origin of the left and right coronary arteries. A LAD branch (short LAD) with an early take-off from the LM entered the proximal interventricular groove and gave rise to the septal branches. The LM then divided into the circumflex branch and the other LAD branch (long LAD), which ran on the left ventricular side of the interventricular groove and entered the groove distally. The major diagonals originated from the latter LAD.

J INVASIVE CARDIOL 2014;26(5):E59-E60

Key words: coronary anomalies, dual LAD

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Case Description

A 49-year-old male presented with a history of mid-sternal chest pain at rest, which resolved spontaneously prior to arrival to hospital. Medical history included current smoking, but no other risk factors for coronary artery disease. There were no electrocardiographic abnormalities and serial cardiac enzymes were negative. The exercise stress test was inconclusive for inducible ischemia. He underwent coronary angiography, which showed normal origin of the left and right coronary arteries. A left anterior descending (LAD) branch (short LAD) with an early take-off from the left main (LM) coronary artery entered the proximal interventricular groove and gave rise to the septal branches. The LM then divided into the circumflex branch and the other LAD branch (long LAD), which ran on the left ventricular side of the interventricular groove and entered the groove distally. The major diagonals originated from the latter LAD. There was a 30%-40% proximal, focal stenosis in the long LAD (Figures 1A-1C; Videos 1-3). The LCX and RCA followed their normal distributions and were free of disease. No definitive cause for the chest pain was identified on further evaluation.

Discussion

Duplication of the LAD coronary artery is a rare anomaly and reported in 1% of individuals with otherwise normal hearts. Dual LAD system has been classified into six types based on the origin and distribution of the long LAD (Figure 2). In the first 3 types, both short and long LADs originate from a common LAD trunk and in the next 3 types the short LAD originates from the LM and the long LAD from the right coronary sinus or RCA and follows anterior, septal, or interarterial course to the interventricular groove.¹ In the current case, the short LAD originates more proximally and separately from the LM, which then divides into the LCX and long LAD. Origin of a branch from the LM before its bifurcation occurs only in its anomalous origin from the right side and a septal course into the interventricular groove.² This is a novel variant that has not been reported in the literature and may be considered as the 7th type of dual LAD system. As with the first 5 types, the current anomaly is innocuous in the absence of coronary artery disease. However, it is important to recognize this variant in patients undergoing revascularization to prevent persistent ischemia.

Acknowledgment. The authors acknowledge Dr Arvin Lamanna for his help with the illustrations in Figure 2.

References

1. Lee Y, Lim YH, Shin J, Kim KS. A case report of type VI dual left anterior descending coronary artery anomaly presenting with non-ST segment elevation myocardial infarction. BMC Cardiovasc Disord. 2012;12:101.
2. Serota H, Barth CW 3rd, Seuc CA, Vandormael M, Aguirre F, Kern MJ. Rapid identification of the course of anomalous coronary arteries in adults: the “dot and eye” method. Am J Cardiol. 1990;65(13):891-898.