The aortic outflow and root: a tale of dynamism and crosstalk

doi:10.1016/S0003-4975(99)00745-6

The Annals of Thoracic Surgery

Volume 68, Issue 3, Supplement 1, September 1999, Pages S37-S43

Presented at the 80th Birthday Celebration of C. Walton Lillehei, PhD, MD, Minneapolis, MN, Oct 23–25, 1998.

https://doi.org/10.1016/S0003-4975(99)00745-6 Get rights and content

Abstract

Although the aortic outflow and root (AoR) constitute a short channel connecting the left ventricle to the aorta, its different components have been shown to be highly specialized structures, interacting with each other as well as with surrounding structures, thus providing a “tale of dynamism and crosstalk.” Thorough knowledge of the AoR and morphological and structural changes, that occur during pathological processes, can have important implications in evolving and executing surgical procedures designed to preserve and restore the “dynamism and crosstalk.” The crown-shaped annulus, fibrous trigones, aortic cusps components, aortic sinuses, and the sinotubular junction share a dynamic coordinated behavior, which can be partially or completely restored in various repair or replacement procedures of the AoR. The interaction and the specific operations are presented with evidence supporting the notion that the dynamic behavior of the root does influence the pattern of instantaneous movements of the aortic cusps after different types of operations. Further studies are required to evaluate the influence of adopting these ideas on the long-term results of operative procedures.

Section snippets

Functions of the aortic root

The prime function of the AoR is unidirectional transmission of large volumes of blood pumped intermittently through the channel while mainaining laminar flow, minimal resistance, optimal coronary flow, and least tissue damage during widely variable and frequently changing conditions. These functions have major implications to maintaining left ventricular performance, and possibly structural integrity and hence survival and quality of life. The amount of blood pumped through the AoR (channel)

Strategic position of the aortic root

The AoR are wedged in a central, largely intracardiac position and are intimately related to almost all vital parts of the heart. These include the left ventricular myocardium, the mitral valve, the muscular and membranous interventricular septa, the right and left fibrous trigones, the conducting atrioventricular tissue, the right and left atria, and, most importantly, the two coronary ostia (Fig 1).

Components of the aortic root: the major players

The AoR extends from the level of the tip of the anterior leaflet of the mitral valve to the level of the sinotubular junction. For the sake of convenience, it can be divided into a subvalvular (left ventricular outflow tract [LVOT]) and supravalvular (aortic root) region.

The LVOT consists of a fibromuscular tube with the muscular and membranous interventricular septa forming the anterior wall, and the subaortic curtain and anterior leaflet of the mitral valve forming the posterior wall. The

Dynamism, crosstalk, and hemodynamics

The aortic root as a whole, as well as its component parts, are dynamic in that they move spatially and alter their shape and/or size in an integrated manner during the different parts of the cardiac cycle. These movements have important hemodynamic effects. The entire aortic root moves downwards towards the left ventricle during systole. This could be responsible, at least in part, for the early opening of the aortic valve before movement of the blood from the ventricle.

For a long time, the

The aortic root and flow dynamics through the heart

Blood flow through the aortic root is an integral part of flow through the heart as a whole. In vertebrates, this has evolved to make use of interaction between basic fluid dynamics and contractile rhythmic contraction of the heart, providing the highly dynamic circulation required for these potentially extremely active organisms.

Sinuous intracardiac flow paths are shared by all vertebrates, with changes of direction of flow becoming increasingly marked through fish, amphibians, reptiles, and

Surgical implications

This view of morphodynamic heart function favors surgical approaches that conserve, as far as practicable, the geometry and mobility of cardiovascular tissues. In particular, functional and structural interactions of different components of the aortic outflow and root can have many implications in the choice and/or implementation of surgical treatment of different conditions affecting the aortic root. In this article, only four examples will be discussed.

Conclusions and future directions

The accumulating knowledge about the dynamic behavior of the aortic root has served to identify several important structures and events that have important influence on the hemodynamics of the aortic root. Future studies to characterize further the structure and function of the aortic roots using molecular and bioengineering tools could help advance our knowledge in this area. This could be of value in improving the overall management of the patients and possibly evolving new types of valve

Acknowledgements

Professor Magdi Yacoub, Dr Philip Kilner, and Dr Emma Birks are supported by The British Heart Foundation.

References (27)

R.J. Brewer et al.
The dynamic aortic rootits role in aortic valve function
J Thorac Cardiovasc Surg
(1976)
M. Higashidate et al.
Regulation of the aortic valve opening
J Thorac Cardiovasc Surg
(1995)
M. Thubrikar et al.
The mechanism of opening of the aortic valve
J Thoracic Cardiovasc Surg
(1979)
J. Zimmerman et al.
The surgical significance of the fibrous skeleton of the heart
J Thorac Cardiovasc Surg
(1962)
M. Thubrikar et al.
The cyclic changes and structure of the base of the aortic valve
Am Heart J
(1980)
G.W. Christie et al.
Biaxial mechanical properties of explanted aortic allograft leaflets
Ann Thorac Surg
(1995)
M.H. Yacoub
Valve-conserving operation for aortic root aneurysm or dissection
M.H. Yacoub et al.
Anatomical correction of the syndrome of prolapsing right coronary aortic cusp, dilatation of the sinus of valsalva, and ventricular septal defect
J Thorac Cardiovasc Surg
(1997)
M. Thubrikar
The aortic valve
(1990)
B.J. Bellhouse et al.
Mechanism of closure of the aortic valve
Nature
(1968)

M.H. Yacoub et al.

Mobilization of the left and right fibrous trigones for relief of severe left ventricular outflow obstruction

J Thorac Cardiovasc Surg

(1999)

J. Zimmermann

The functional and surgical anatomy of the heart

Ann Roy Coll Surg Engl

(1966)

C.S. Peskin et al.

Mechanical equilibrium determines the fractal fiber architecture of aortic heart valve leaflets

Am J Physiol

(1994)

Cited by (168)

Aortic valve-sparing variants are getting closer
2024, JTCVS Techniques
The Natural History of Bicuspid Aortic Valve Disease
2023, Structural Heart
Citation Excerpt :
In contrast, the “anatomic annulus” is the coronet-shaped structure formed where the cusps attach to the walls of the sinuses of Valsalva and sinotubular junction (the red crown-like ring in Figure 5). These same tissue relationships describe both BAV and tricuspid aortic valve (TAV) anatomic annuli.37 Despite similar anatomic annuli, the surgical annuli differ between BAV and TAV.
The bicuspid aortic valve (BAV) is the most common congenital heart defect with an estimated prevalence of between 0.5% and 2% in the United States, representing up to 6.5 million individuals. Most individuals with BAV will develop valvular and/or aortic complications related to their BAV. How these various complications relate to one another and why they arise remain elusive. Yet, astute observations have yielded relevant classification systems that leverage valvular morphology, aortic shape, and genetic alteration patterns. Emerging evidence supports the existence of BAV phenotypes that may have different patterns of disease presentation, rates of progression, and risk of secondary complications. We review the natural history of BAV in light of known classification systems to illustrate a framework through which future hemodynamic, cell biologic, and other studies can better correlate with clinical endpoints. Consistent utilization of valvular, aortic, and genetic classification systems in the management and study of BAV may facilitate insight into the patterns of the disease, with prognostic and therapeutic significance for individuals who experience this common structural heart disease.
Commentary: Preventing pulmonary autograft dilatation: Many unanswered questions
2023, Journal of Thoracic and Cardiovascular Surgery
Commentary: The Ross procedure in a polyethylene terephthalate graft: Is everything OK in there?
2023, Journal of Thoracic and Cardiovascular Surgery
Commentary: Vitruvius lives on
2022, Journal of Thoracic and Cardiovascular Surgery
A New Technique for Shaping the Aortic Sinuses and Conserving Dynamism in the Remodeling Operation
2021, Annals of Thoracic Surgery
Preserving dynamism and recreating the sinuses in the Dacron graft are thought to be important for optimizing results of aortic valve-conserving operations.
We describe a novel technique that preserves dynamism and recreates the sinotubular junction. In addition, it tailors 3 sinuses of defined longitudinal and transverse curvatures in a straight Dacron tube during the operation. The technique has been used in 6 patients with varied aortic root pathology. We performed preoperative and postoperative multimodality imaging using computerized image analysis as well as 3-dimensional models.
There was no early or midterm death. Upon discharge, patients were clinically well, with echocardiographic evidence of minimal (3 patients) or mild (3 patients) aortic regurgitation. Computed tomography and cardiac magnetic resonance imaging with extensive image analysis of the aortic root size, shape, and function showed partial or complete normalization of these parameters. This included the shape and dynamism of the aortic annulus and the size and shape of the geometric (effective) orifice. The 4-dimensional magnetic resonance imaging pattern of flow in the sinuses and ascending aorta showed favorable vortices in the sinuses, right-handed helical flow, and marked diminution of energy loss in the ascending aorta.
The novel technique described here is simple, practical, and cost-effective because it uses a widely available straight Dacron tube. The technique does not use rigid internal or external support. The early results are encouraging. Larger series with longer follow-up are required.

View all citing articles on Scopus

View full text

Original ArticlesThe aortic outflow and root: a tale of dynamism and crosstalk

Abstract

Section snippets

Functions of the aortic root

Strategic position of the aortic root

Components of the aortic root: the major players

Dynamism, crosstalk, and hemodynamics

The aortic root and flow dynamics through the heart

Surgical implications

Conclusions and future directions

Acknowledgements

J Thorac Cardiovasc Surg

J Thorac Cardiovasc Surg

J Thoracic Cardiovasc Surg

J Thorac Cardiovasc Surg

Am Heart J

Ann Thorac Surg

J Thorac Cardiovasc Surg

The aortic valve

Mechanism of closure of the aortic valve

Nature

Mobilization of the left and right fibrous trigones for relief of severe left ventricular outflow obstruction

J Thorac Cardiovasc Surg

The functional and surgical anatomy of the heart

Ann Roy Coll Surg Engl

Mechanical equilibrium determines the fractal fiber architecture of aortic heart valve leaflets

Am J Physiol

Original Articles
The aortic outflow and root: a tale of dynamism and crosstalk