Letter to the editor Could Descending Septal Artery Be Another Variant of the Dual Left Anterior Descending Artery?

To the Editor,

We read with great interest the article by Montero-Cabezas et al,¹ which prompted us to ask the question forming the title of this letter.

Absence of the first septal branch of the left anterior descending artery (LAD) on left coronary angiography not only raises the suspicion of the presence of a descending septal artery, or Bonapace's branch, as mentioned by the authors themselves mention,¹ but also clearly demonstrates the existence of a congenital coronary anomaly of the LAD.

According to Spindola-Franco et al,² the LAD is the coronary artery with the most constant origin, course, and distribution in the human heart; however, many anatomical variants have been described in the literature.^2–10

Such congenital coronary anomalies are rare. Their incidence is between 0.64% and 1.3% but can reach almost 6%. Dual LAD represents 1.2% to 6.1% of all coronary anomalies.³

Notably, the definition of the descending septal artery by Montero-Cabezas et al¹ has similarities to the updated classification of type IV dual LAD,³ except that it could be considered the opposite: in the description by Montero-Cabezas et al, it is the short LAD (in this case the descending septal artery) that originates from the right coronary artery, or close to it, and the long LAD continues normally as a branch of the left coronary artery (Figure 1).

Figure 1.

Type V left anterior descending artery. Modified with permission from Moreno-Martínez et al,³ showing a graphical representation of the other types of dual left anterior descending artery. Cx, circumflex artery; LAO, left anterior oblique; LCA, left coronary artery; L-LAD, long left anterior descending artery; RAO, right anterior oblique; RCA, right coronary artery; RV, right ventricle; S-LAD, short left anterior descending artery.

In such cases, the descending septal artery could be considered a new type of dual LAD, rather than an isolated variant of coronary anomalies. The types proposed by Montero-Cabezas et al¹ would constitute its anatomical variants; therefore, the classification of dual LAD would remain as described in Figure 2.

Figure 2.

Classification of the types and subtypes of dual left anterior descending artery (respecting the classic description by Spindola-Franco from 1983²) Modified with permission from Moreno-Martínez et al.³ AIVS, anterior interventricular sulcus; DSA, descending septal artery; LAD, left anterior descending artery; LCA, left coronary artery; LV, left ventricle; RCA, right coronary artery; RV, right ventricle.

The possibility of combining these types of anomaly of the origin, course, and distribution of the LAD could have important implications in clinical practice.