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Transconal Unroofing of Anomalous Left Main Coronary Artery from Right Sinus With Transseptal Course

Thursday, January 27, 2022

Oh N, Karamlou T, Najm H. Transconal Unroofing of Anomalous Left Main Coronary Artery from Right Sinus With Transseptal Course. January 2022. doi:10.25373/ctsnet.19083215

Anomalous aortic origin of the left coronary artery (AAOLCA) from the right coronary sinus is a rare condition. However, this disease process is clinically important because it carries an increased risk of sudden cardiac death in otherwise healthy young people. This is especially true when compared to anomalous right coronary arteries.

Anatomically, after its origin from the right coronary sinus, the anomalous left main coronary artery takes one of four courses:  

  • Front of the pulmonary artery 
  • Behind the aorta 
  • Between the pulmonary artery and aorta 
  • Transseptal course 

In the transseptal variant shown in the video above, the left main coronary artery dives into the interventricular septum behind the right ventricular outflow tract and emerges on the epicardial surface, on the lateral aspect of the pulmonary annulus, before bifurcating into the left anterior descending artery and left circumflex coronary arteries.  

This variant can be surgically challenging to repair with conventional techniques. Coronary artery bypass grafting has been advocated, but it proves to be a suboptimal solution because of early risk of failure from competitive flow. Recently, our group developed a novel transconal approach that has not been previous described and that adequately addresses the pathophysiologic issues with this variant. This technique has been demonstrated to provide improved fractional flow and reserve values compared to preoperative values; address the underlying pathophysiology of this variant; and serve as a safe and effective alternative to conventional surgical solutions.


  1. Najm HK, Ahmad M. Transconal Unroofing of Anomalous Left Main Coronary Artery From Right Sinus With Trans-septal Course. Ann Thorac Surg. 2019 Dec;108(6):e383-e386. doi: 10.1016/j.athoracsur.2019.04.021. Epub 2019 May 15. PMID: 31102634.


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