• Home
  • Aim of this blog

Dr.S.Venkatesan MD

Expressions in cardiology

Feeds:
Posts
Comments
« Coronary artery and veins are married life long . . . with a purpose !
Why pleural effusion is more common on right side in cardiac failure ? »

Is cardiac valves really (a)vascular structures ?

October 18, 2018 by dr s venkatesan

Though heart is known primarily as a pump, it is the four cardiac valves that ensures the critical , non-stop unidirectional flow that sustain the circulation . It is to be recalled these valves originate in the very early days of cardiac development when the primitive heart tube loops , even as the chambers expand from primitive ventricle. Mesenchymal differentiation controlled by various genes that cleaves the valve from myocardial tissue.

While heart by itself is the supreme vascular organ ,  its surprising  few structures inside the heart , like the valves are quiet avascular ( or is it really so ?)

The valves that beat average of 30 billion time in life time ,seem  to get its nourishment from Nowhere ?

Layers of heart valve 

 

Image source : Huk D., Lincoln J. (2017) Oxidative Stress in Cardiac Valve Development. In: Rodriguez-Porcel M., Chade A., Miller J. (eds) Studies on Atherosclerosis. Oxidative Stress in Applied Basic Research and Clinical Practice. Humana Press, Boston, MA

It’s primarily made up of  complex stratified connective tissue covered by endothelial cells with intervening interstitial cells. The extracellular matrix (ECM) layers are rich in elastin proteoglycan (spongiosa) and collagen (fibrosa). It has been found myocytes and dormant fibroblasts are scattered in the valve leaflets. This forms the basis of focal origins of  Cuspal Ventricular tachycardia J Cardiovasc Electrophysiol. 2002 Jun;13(6):551-6.  from electricaly activated myocytes.

Is there a dynamic cell turnover within the valve tissue ? Where does it get the nourishment ? What is the effect of  aging and CAD on valve tissue ? 

There is growing evidence for valvular extra cellular  matrix are indeed dynamic. This explains valvular lesions in connective tissue disorders like Rheumatoid arthritis. Progressive degenerative changes of aging  involves  remodelling , tissue engineering . Calcification of cardiac valves in endocrine disorders like  hyperparathyroid states implies  cardiac valvular interstitium is in continuum of systemic metabolic pool. There has been very little published evidence  correlating  CAD and Ischemic degeneration of valve.

Evidence for vascularity of valves

It is surprising , this simple question of  vascular supply to cardiac valves has  confronted the scientists for too long.

1.Histopathological and  autopsy studies have revealed vascular channels.(Harper 1938 BMJ)

2.X-ray projection microscopy was used to image the valves after injecting radio opaque microparticles in the ascending aorta. This is probably the one of the few original studies done in UK in 1968 (Clarke et al ) it revealed significant  vascularity of the valve .It was found 16 % the tricuspid valve, in 10% of the mitral valve, and was maximum in Aortic valve (24%).

3.The fact that statins reach the Aortic valve tissue in lipomatous Aortic stenosis indicate significant vascular port of entry to valves.

Direct evidence : Why don’t we ask the surgeon ?

When I asked my surgical colleagues  Does the valve  bleed  as they cut it  ? Most of them were amused with my query , still Iam not sure I got the answer right. At least one of them said since the heart is on pump ,  it won’t bleed any way !

 

Conclusive evidence : From a 1968 study 

It is academically humiliating to note we have to go back 50 years in time to get a proof for vascularity in cardiac valve.(Or anything new I am missing ? readers may share !) I think , this is strongest proof  for valve cusps are supplied by end coronary arteries. However the penetrance is not deep into all layers of the valve and distally

Is hematogenous spread of Infective endocarditis(IE) occur ?

How does systemic infection reach the valves ? We still believe the IE is due to direct colonisation from circulating blood .Hematogenous spread of IE do occur but difficult to prove. It seems infection of valves primarily happen from outside initiated by  endothelial injury over the valves .

*There seems to be a contribution from  systemic bacteremia  reaching  from within through the pre-existing capillary twigs as well.(Evidence elusive !)

 

Final message

Is cardiac valves vascular ?  It is curious even in this era , we struggle to answer this query with certainity.

Yes, they are vascular structures , but at best it has partial vascular capillary network. It is also possible  the valves can live a durable life even without these vascular Innervation.(I haven’t heard of a condition called mitral valve infarct or necrosis in RCA/LCX STEMI which supply the base of the heart)

Still, this partial  vasculaity can become Important at times of pathology like infection or degeneration. Expecting more research in this unique area of valvular heart disease

Reference

1.JOHN A. CLARKE AN X-RAY MICROSCOPIC STUDY OF THE BLOOD SUPPLY TO
THE VALVES OF THE HUMAN HEART BY   From the Department of Anatomy, University of Glasgow, Glasgow Brit. Heart J., 1965, 27, 420

2.https://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC1252531&blobtype=pdf

3.Dow, D.R. and Harper, W.F. The vascularity of the valves of the human heart. J Anat. 1932; 66: 610–617

4.Ritter, S.A., Gross, L., and Kugel, M.A. Blood vessels in the valves of normal human hearts: from a study of 700 human hearts. Am Heart J. 1928; 3: 433–446

5. Saini N, Saikia UN, Sahni D, Singh RS.  Vascularity of human atrioventricular valves: a myth or fact? J Thorac Cardiovasc Surg. 2014 Jan;147(1):517-21. 

Rate this:

Share this:

  • LinkedIn
  • WhatsApp
  • Twitter
  • Facebook
  • Email

Like this:

Like Loading...

Posted in cardiac embryology, Embryology : Heart valve development, Infective endocarditis : Pathology, valvular heart disease | Tagged blood supply to heart valves, hematogenous spread of infective endocarditis, how bacteria reach mitral valve in infective endocarditis, is cardiac valves vascular avascular ?, is mitral valve avascular ?, layers of mitral valve, mitral valve vascularity, three layers of heat valves |

  • Categories

  • Archives

    • May 2023 (5)
    • April 2023 (4)
    • March 2023 (5)
    • February 2023 (2)
    • January 2023 (7)
    • December 2022 (3)
    • November 2022 (5)
    • October 2022 (5)
    • September 2022 (4)
    • August 2022 (3)
    • July 2022 (9)
    • June 2022 (2)
    • May 2022 (1)
    • April 2022 (2)
    • March 2022 (1)
    • February 2022 (3)
    • January 2022 (7)
    • December 2021 (3)
    • November 2021 (5)
    • October 2021 (8)
    • September 2021 (4)
    • August 2021 (6)
    • July 2021 (6)
    • June 2021 (7)
    • May 2021 (5)
    • April 2021 (4)
    • March 2021 (3)
    • February 2021 (6)
    • January 2021 (8)
    • December 2020 (4)
    • November 2020 (5)
    • October 2020 (7)
    • September 2020 (7)
    • August 2020 (10)
    • July 2020 (6)
    • June 2020 (9)
    • May 2020 (9)
    • April 2020 (5)
    • March 2020 (7)
    • February 2020 (3)
    • January 2020 (4)
    • December 2019 (4)
    • November 2019 (6)
    • October 2019 (3)
    • September 2019 (6)
    • August 2019 (3)
    • July 2019 (1)
    • June 2019 (3)
    • May 2019 (2)
    • April 2019 (2)
    • March 2019 (2)
    • February 2019 (4)
    • January 2019 (2)
    • December 2018 (2)
    • November 2018 (2)
    • October 2018 (2)
    • September 2018 (1)
    • August 2018 (2)
    • July 2018 (3)
    • June 2018 (1)
    • May 2018 (3)
    • April 2018 (1)
    • March 2018 (3)
    • February 2018 (3)
    • January 2018 (1)
    • December 2017 (3)
    • November 2017 (3)
    • October 2017 (3)
    • September 2017 (2)
    • August 2017 (2)
    • July 2017 (2)
    • June 2017 (2)
    • May 2017 (4)
    • April 2017 (3)
    • March 2017 (3)
    • February 2017 (5)
    • January 2017 (3)
    • December 2016 (2)
    • November 2016 (5)
    • October 2016 (4)
    • September 2016 (3)
    • August 2016 (5)
    • July 2016 (3)
    • June 2016 (4)
    • May 2016 (3)
    • April 2016 (6)
    • March 2016 (4)
    • February 2016 (3)
    • January 2016 (5)
    • December 2015 (6)
    • November 2015 (5)
    • October 2015 (8)
    • September 2015 (2)
    • August 2015 (5)
    • July 2015 (7)
    • June 2015 (4)
    • May 2015 (6)
    • April 2015 (5)
    • March 2015 (7)
    • February 2015 (15)
    • January 2015 (8)
    • December 2014 (5)
    • November 2014 (9)
    • October 2014 (7)
    • September 2014 (9)
    • August 2014 (5)
    • July 2014 (11)
    • June 2014 (5)
    • May 2014 (4)
    • April 2014 (5)
    • March 2014 (8)
    • February 2014 (8)
    • January 2014 (5)
    • December 2013 (7)
    • November 2013 (7)
    • October 2013 (14)
    • September 2013 (12)
    • August 2013 (15)
    • July 2013 (15)
    • June 2013 (15)
    • May 2013 (15)
    • April 2013 (15)
    • March 2013 (15)
    • February 2013 (15)
    • January 2013 (15)
    • December 2012 (15)
    • November 2012 (15)
    • October 2012 (15)
    • September 2012 (15)
    • August 2012 (15)
    • July 2012 (15)
    • June 2012 (15)
    • May 2012 (15)
    • April 2012 (15)
    • March 2012 (15)
    • February 2012 (15)
    • January 2012 (15)
    • December 2011 (15)
    • November 2011 (17)
    • October 2011 (17)
    • September 2011 (17)
    • August 2011 (21)
    • July 2011 (20)
    • June 2011 (17)
    • May 2011 (15)
    • April 2011 (17)
    • March 2011 (25)
    • February 2011 (20)
    • January 2011 (20)
    • December 2010 (18)
    • November 2010 (21)
    • October 2010 (21)
    • September 2010 (25)
    • August 2010 (20)
    • July 2010 (10)
    • June 2010 (11)
    • May 2010 (19)
    • April 2010 (16)
    • March 2010 (14)
    • February 2010 (22)
    • January 2010 (18)
    • December 2009 (20)
    • November 2009 (20)
    • October 2009 (3)
    • September 2009 (21)
    • August 2009 (19)
    • July 2009 (12)
    • June 2009 (12)
    • May 2009 (11)
    • April 2009 (15)
    • March 2009 (21)
    • February 2009 (4)
    • January 2009 (12)
    • December 2008 (13)
    • November 2008 (9)
    • October 2008 (22)
    • September 2008 (20)
    • August 2008 (16)
    • July 2008 (14)
    • June 2008 (7)
  • Blog Stats

    • 6,073,176 hits
  • Please give your feed back .

  • Click below to see who is watching this website live !

  • This site will never aim for profit. Still ,this donation link is added at the request of few visitors who wanted to contribute and of-course that will help make it sustainable . Donate Button with Credit Cards
  • Please Note

    The author acknowledges all the queries posted by the readers and wishes to answer them .Due to logistic reasons only few could be responded. Inconvenience caused is regretted.
  • Live 3D global traffic map Stats

WPThemes.


  • Follow Following
    • Dr.S.Venkatesan MD
    • Join 833 other followers
    • Already have a WordPress.com account? Log in now.
    • Dr.S.Venkatesan MD
    • Customize
    • Follow Following
    • Sign up
    • Log in
    • Copy shortlink
    • Report this content
    • View post in Reader
    • Manage subscriptions
    • Collapse this bar
 

Loading Comments...
 

    %d bloggers like this: