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Archive for the ‘cardiac anatomy’ Category

Left main bifurcates into two , that’s  the classical anatomical behavior of LCA. (Or it trifurcates) When left main divides , it tends to share its diameter between its two siblings LAD and LCX with considerable  whims and fancies.(Though Finet* et all thought it has a working rule !) * From  Biomedical Engineering, Cardiovascular Hospital and Claude Bernard University France

Now , have a look at this , its a rare example of  how a left main might Ignore the rule of bifurcation just like that !

Left main simply continues as left main* after giving off a casual side branch from mid left main shaft .Yes , Its a innocuous looking LCX which would be non dominant as expected

LCX arises exactly mid way in left main , (Technically LAD begins at this point ) but , can you find any difference in the left main after giving off  LCX branch.

Can we say left main continues as LAD without a bifurcation ?

Or shall we say  left main gives off a premature early side branch ( true LCX)  non bifurcating  branch ?

It is an unusual anatomy and  as expected , this patient had a dominant  RCA .

What could be the clinical implication for such a premature  LCX ?

We can only guess . May be nothing !  Obviously ,these patients are immune to develop true bifurcation lesion. Does it in any way mean they have anatomically blessed coronaries !

 

Reference 

1.Finet G1, Gilard M, Perrenot B Fractal geometry of arterial coronary bifurcations: a quantitative coronary angiography and intravascular ultrasound analysis. , EuroIntervention. 2008 Jan;3(4):490-8.
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Hey , What’s that moving object over  AML ?  It looks odd,  it doesn’t look like a thrombus or a vegetation.

Yes, I agree , its moving  independently  but  I think , Its benign threads of fibrin attached to the valve .They are called as valvular strands.

Is it ?, I haven’t heard about it !  Can you please  tell me something about it.


Strands are  highly mobile, fine, filiform  threadlike excrescences that is seen arising from valvular structures. Synonym : Its same as Lambl’s excresceneces , the Czech physician who described  it over Aortic valve in 1860.

The following TEE clip shows strands attached to Aortic valve

Incidence

Reported Incidence of valvular strands  varies .Some reports suggested it may be up to 5-10 % .( SPARC study Mayo clinic 1999 its staggering 46 % !)The reason for  such high incidence  is,   many of us are still not clear what we refer to as strand.The imaging modality also has a say. With improving resolution of TTE and liberal TEE use more  strands are detected .A recent large study from Israel , suggest a good news , in large population based study (21,000) true strands are  observed in  just around  1 %.(Marina Leitman 2014 )

Is it Physiological or Pathological ?

The valve closure lines are physiologically stressed , some amount of denudation of endothelium is expected .This leads to a thrombus formation along with the exposed mucopolysacchride  layers of the valve form a filiform ,filamentous structure. .To call it physiological or pathological is left to our wisdom and  perception. The size however matters. It could be  the reason behind many  unexplained strokes.

What is the natural history of these strands ?

Its difficult to believe It may persist for lifetime.If its truely fibrinous strands it may have a life cycle and disappear.

Size

Should be less than 1 mm.

Length varies between  3 mm to 5 mm

Location 

Can be seen in any valve or even in aortic root.

Attachment : Atrial side of mitral valve and ventricular side of Aortic valve.

Strands over prosthetic valve is also reported.

Clinical significance 

It has three common issues.

One: Getting confused with other more pathological entities.

Two : Risk of stroke.

Three: Nidus for normal native valve endocarditis ?

Strands may closely mimic 

  • Vegetations
  • Bland thrombus
  • Redundant leaflet /Chrodae (Marfan and variants)
  • Disrupted chordae (After MVR)
  • Flail leaflet
  • Fibroelastomas

Risk of dislodgement and  stroke 

These strands are minute. It seems plausible dislodgement need not necessarily result in stroke or other organ ischemia.We don’t know whether it gets dissolved on transit.However the risk of stroke is increased in most reports except few studies(Roldan).

Management

First question to ask is , Should we inform our patients about  these ubiquitous accessory valve  tissues if detected incidentally ?

Largely benign and can be ignored in most.A follow up echo may be adviced once in a year or 2. (I have one anxious patient  after I reported such strands in Marfan syndrome )

In patients who has h/o stroke presence of these strands gains importance and  is an indication for anticoagulation.

Surgical excision of large strand is a dramatic option and is rarely performed.

Queries with no answers 

Is it accessory valvular (mesenchymal) tissue ?

Does Atheromatous plaque contribute to these strands in Aortic valve ?

Strands , if  disappears  by natural means , do they regrow from the same spot of raw surface  ?

Final message 

Fibrous strands detected  over the valves by routine echo are uncommon .However , It may give considerable  anxiety if  documented and reported to our patients and physicians .Though these have negligible clinical significance , the risk of stroke is increased in those with large strands.

Reference

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