Aortic sinuses

Anatomy of the aortic valvar complex

An aortic sinus, also called the sinuses of Valsalva is one of the anatomic dilations of the ascending aorta, which occurs just above the aortic valve. These widenings are between the wall of the aorta and each of the three cusps of the aortic valve. There are generally three aortic sinuses: one anterior and 2 posterior sinuses.

Aortic sinuses

Figure 3. Aortic sinuses

 
The regions corresponding to the luminal surface of the three bulges of the aortic root, which support their respective valvar leaflets, are known as the aortic sinuses of Valsalva (Figure 3).

Usually, the right and left sinuses give rise to coronary arteries (right and left), while the third sinus does not. Because of this, the third sinus is usually described as the non-coronary sinus. On rare occasions, nonetheless, a coronary artery can arise from this third sinus. We prefer, therefore, to describe the sinuses as being right coronary, left coronary, and non-adjacent. The"œnon-adjacency” is considered relative to the sinuses of the pulmonary trunk. When considered attitudinally, the sinuses are located anteriorly (right coronary), leftward and posteriorly (left coronary), and rightward and posteriorly (non-adjacent)7. The mean diameter of the sinuses of Valsalva as measured with multidetector computed tomography (MDCT) was 32.4 ± 4.0 mm9Prosthesis size was not significantly different between patients with and without aortic stenosis10.

 This close-up view of the aortic root from the base of the heart demonstrates the relationship between the atrioventricular valves, the anterior wall of the atriums and the pulmonary trunk. The aortic root is located at the centre of the heart and is deeply wedged between the atrioventicular valves. The subpulmonary muscular infundibulum and the pulmonary trunk wrap around the anterior aspect of the aortic root. The two aortic sinuses that lie adjacent to the pulmonary trunk are called the right (red star) and left (blue star) facing sinuses, the right facing sinus typically giving rise to the right coronary artery and the left facing sinus the left coronary artery. The sinus marked by the (yellow star) is the non-adjacent sinus and is farthest from the pulmonary trunk. The zones of apposition between the three aortic valvar leaflets extend from the thickened areas within the aortic wall (black stars) to the central portion of the valvar orifice, this entire area marked as the commissure. In the past, only the areas at the black stars marking the attachment of the leaflets to the sinutubular junction were referred to as the commissures.

Figure 3. Aortic sinuses (Annotation)

Figure 3. Aortic sinuses (Annotation)

 
1 - Pulmonary valve
2 - Right coronary artery
3 - Tricuspid valve
4 - Mitral valve
5 - Left coronary artery

[Link] Chapter 5 - Vascular complications

As the aortic root is a centrally located cardiac structure within the pericardial sac, rupture of the root or one of its sinuses during TAVI can result in direct communication with several different cardiac chambers:7

  • Non-adjacent sinus: potential communication with the right or left atrium
  • Left coronary sinus: potential communication with the left atrium or the transverse sinus (pericardical space).
  • Right coronary sinus: potential communication with the right atrium or the right ventricular outflow tract.

As it exits the left ventricle, the aortic root angulates slightly towards the right and therefore overlies the superior aspect of the muscular ventricular septum and the right ventricle. Thus, aortic root rupture during TAVI can potentially also produce an interventricular septal communication.