Posterior Descending Coronary Artery Arising From a Septal Branch of the Left Anterior Descending Coronary Artery

J INVASIVE CARDIOL 2017;29(2):E26-E27.

Key words: coronary anomaly, coronary anatomy

A 48-year-old man with longstanding hypertension and tobacco use presented with dyspnea and lower-extremity edema. Transthoracic echocardiography revealed a severely decreased left ventricular ejection fraction. He was referred for cardiac catheterization and coronary angiography for evaluation of the etiology of his cardiomyopathy. The right coronary artery supplied two posterolateral branches without angiographic evidence of coronary artery disease. Angiography of the left coronary system was notable for a long anomalous branch of the proximal left anterior descending coronary artery that coursed inferiorly to give rise to the posterior descending artery. No epicardial coronary artery disease was visualized. The postcatheterization course was uneventful and the patient was discharged home on guideline-directed medical therapy for heart failure. 

Left-dominant coronary circulation is a normal variant that occurs in up to 15% of patients, with the posterior descending artery typically supplied by the circumflex artery. In rare circumstances, abnormalities in embryologic development can lead to anomalous origins of the posterior descending artery. Although congenital anomalies of the coronary arteries are reported in 1%-5% of adults undergoing angiography,¹ only 2 prior cases of a posterior descending artery supplied by a left anterior descending branch have been published.^2,3 In the present case, the large-caliber anomalous branch of the left anterior descending appeared to pass through the interventricular septum, without branching, before giving rise to the posterior descending artery in the inferior atrioventricular groove. The anomalous branch was considered to be an incidental finding, with no pathological contribution to the clinical presentation. This anatomy is distinct from the commonly encountered “wrap-around” left anterior descending, in which the distal portion of the left anterior descending wraps around the left ventricular apex in the inferior interventricular groove and supplies apical inferior myocardium in combination with a posterior descending artery that originates from the right coronary artery or circumflex artery.⁴ 

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References

1.     Angelini P, Velasco JA, Flamm S. Coronary anomalies: incidence, pathophysiology, and clinical relevance. Circulation. 2002;105:2449-2454.

2.    Singh SP, Soto B, Nath H. Anomalous origin of posterior descending artery from left anterior descending artery with unusual intraseptal course. J Thorac Imag. 1994;9:255-257.

3.    Patra S, Srinivas BC, Agrawal N, Manjunath CN. Super dominant left anterior descending artery with origin of both posterior descending artery and posterior left ventricular artery from septal branch. BMJ Case Rep. 2013 Jun 13.

4.    Perlmutt LM, Jay ME, Levin DC. Variations in the blood supply of the left ventricular apex. Invest Radiol. 1983;18:138-140.

From the Leon H. Charney Division of Cardiology, Department of Medicine, New York University School of Medicine, New York, New York.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest regarding the content herein.

Manuscript submitted, August 9, 2016, provisional acceptance given August 15, 2016, final version accepted August 17, 2016.

Address for correspondence: Nathaniel R. Smilowitz, MD, Leon H. Charney Division of Cardiology, Department of Medicine, New York University School of Medicine, 550 1st Avenue, HCC-14th Floor, New York, NY 10016. Email: Nathaniel.Smilowitz@nyumc.org