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Archive for January, 2011

Left main divides into two. Some times into three . Very rarely into 4

Look  at this angiogram ,  This looks  like  a quadrification, if not quadrification equivalent

Clinical implication

A 4 way division invariably means the OM and diagonal or going to be diminutive.These people are expected to have favorable coronary hemodynamics during ACS , and  left main lesions are  less likely  to  occur

Reference

This article is from Singapore medical Journal

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Life cycle of PTCA : Let us hope it do not become extinct !

Does PTCA  , a great Innovation for mankind,  is facing a threat of  extinction ?

It seems so . . . the stents  are losing its shine  in most situations. A simple evidence  . . . for that . . . can  be found in answering the following question

What drives the extensive research in biodegradable stents now ?

The simple answer is , we are fed up with the metals inside the coronary  artery. We want to get rid of it !

Too much of knowledge , often blunts our senses . Our track record clearly  reveals this fact. We needed a major study INTERHEART to tell the world   that  ,exercise is good and tobacco is bad for heart  !  Now ,we forgot a  simplest solution for  getting rid of  metal inside the coronary artery ,  which  is  “not to implant  the stent”  at all ! (Instead we do billion dollar research for making  bio – absorbable stents ,  which in the first place may not be required in the majority !

Read the related article . Does POBA has a role now ? in my site

The only situation  , where PCI   may  withstand the test of time could be in ACS (Both in STEMI and high risk NSTEMI !) PCI is cosmetic in most of the chronic coronary syndromes .

Final message

Our fight against human atherosclerosis will have to be , by medical means .PCI at best will  provide  a supportive role in selected patient group. It requires lots of common sense  and   scientific ignorance to achieve this.   Risk reduction ,  prevention , optimal   medical therapy  will have to play a dominant role in the next few decades .  This is something similar to the environmental issues we face in protecting our planet .No amount of green industry  will protect  the earth . It requires better social and  behavioral  ethics  from  mankind   and their  rulers !

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God creates life  with  infinite variation .  The  heart gets  bulk of its blood supply from the left coronary  artery , which divides into two  after a short course.  Bifurcation is the rule . Left main becomes  left circumflex and LAD  in about in 85-90 %.

Note the left main divides into 3 equal caliber vessels.very lucky to have such a branching pattern !Distal left main is unloaded by three large ostia . This makes stasis of blood in left main very unlikely . LAO caudal view

 

 

Note : The OMs are small in these people. RAO caudal view

Few men and women are blessed with three branches from LCA . The anatomical and physiological importance of this  branching pattern  is not well analysed in the literature .There  could be  few advantages  of having a trifurcation instead of  bifurcation .

  • Left main  impedence is less in trifurcation . This is due to the fact ,  left main empties into three distinct ostia rather than two.The combined  cross sectional area of these three ostia  confers a hydrodyamic advantage.
  • The importance of  any proximal LAD lesion in these patients , is negated  by  33 % as two other vessels are there to take care the  rest of the heart.
  • A large Ramus usually  supplies a vast area in the angle between LAD and LCX.  This   has a potential  to protect against ventricular  fibrillation during acute occlusion of LAD  by providing  electrical stability .

Disadvantage of trifurcation !

  • It is also a fact , people with a large Ramus may have a trade off by having a diminutive diagonal or OM .
  • A trifurcation with a small calibered  ramus  can often  be a disadvantage , as it is prone for atherosclerosis  since it  restricts  left main flow  by  venturi effect . (The first rule of atherosclerosis states its  prone at branching points)

* A related blog  elsewhere in my site . The explanations  offered above are based on personal observation .

https://drsvenkatesan.wordpress.com/2008/12/16/what-is-clinical-significance-of-ramus-intermedius-coronary-artery/

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Few web sites provide   free  cardiology  service.  This one from cardiomath beats  all  ! It makes the job easier for all those cardiologists who spend  lots of time in echo lab . It provides  simple  online tool  for all common calculations in clinical echocardiography

Here is  the link to the website of cardiomath

With  due  Courtesy   to

Author: Dr. Chi-Ming Chow  Developer: Edward Brawer  Illustrator: Ellen Ho
Sponsored by  Canadian society of echocardiography

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Nothing in this world is black and white. In fact,  most events are in between . The irony is , our brain  always wants to view  things in two distinct entities !

  • Success or failure
  • Beautiful or ugly
  • Good or bad
  • Win or lose,
  • Rich and poor etc . . . etc

So it is no  surprise !  cardiologists  also travel in the same boat !

They classified  the events after thrombolysis   into two dogmatic categories . Successful  thrombolysis or failed thrombolysis   . . .  as if no other event  can occur in between .

Traditionally 50% regression of ST segment is called successful .   What  about 30%  and 40 % ST regression ?

Further , there is an important caveat  in the timing,  as we  traditionally assess ,  90 minutes of thrombolysis .

Consider the following  situation  :

  1. Thrombolysis  is failed at 90 minutes, but  succeeds  at 120/180  minutes ?
  2. Is 50 % ST regression at 180 minutes is as bad  or as good as 25 % regression at 90 minutes ?
  3. How to label a patient who  is extremely comfortable in spite of ECG criteria of failed thrombolysis ?(Surprisingly this situation is fairly common !)

So, without finding answers to some critical questions , we have defined the success  of thrombolysis with  half baked data .

This is exactly , is the reason we  are unable to do a  valid  study on failed thrombolysis, rescue PCI etc .  We know the results of rescue PCI  ,  always  been  contradictory to the general logic !

It is estimated a substantial number of  STEMI patients following   thrombolysis   fall into a category of partially successful thrombolysis implying partial restoration of blood flow and salvage. The correct definition for  successful thrombolysis and reperfusion should be at the myocardial mass level , and  not at the level of coronary artery.The ECG  is the best available indicator.

Implication for having a  poor definition  of  failed thrombolysis

It is not a rare sight to wheel  in , a patient to a cath lab  with label of failed thrombolysis dangling in his neck  who is clinically  stable  (Has a less than required 50%  ST regression , but a definite, favorable trend with a 30 % ST regression  at 90 minutes  )

How many cardiologists will be willing to abort a CAG/PCI  , as a repeat ECG just  before puncturing  in the  cath lab reveals    successful  thrombolysis ? (little  delayed though !)

If only we have better methods to risk stratify patients following thrombolysis , we can avoid

  • Huge costs incurred
  • Expected and unexpected hazards of doing an emergency  intervention in an adequately salvaged STEMI
  • Hundreds of cardiology man hours can be saved  for better purposes .

Final message

Classifying thrombolyis into  success  or  failure  is a  skewed  way of looking  at this important  issue .

It is an irony ,  cardiologists often  triage LV dysfunction , valve disease , cardiac failure  etc  into 4  grades (  minimal  , mild , moderate or severe  ) . It is  still a mystery ,  why thrombolysis  is never graded  like that ,  and it is always considered as  all or none phenomenon !

There is a substantial number of patients  with partially successful ( or shall we call partially failed !) thrombolyis  .This group must be given adequate attention or inattention  . There  is a urgent need for a through review of how we look at  the post thrombolysis status  . It is better to use the newer imaging modalities like PET/MRI more  liberally to identify  exact sub group  of failed thrombolysis who will benefit form revascularisation .

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Is it not ,  boring to  see  normal coronary arteries every day  ! There need to be surprises  in cath lab to make our time lively  and keep our brain alert .  Have a look at this angiogram in  RAO caudal view.One of our junior cardiology fellows thought it was  a split left main artery .

How can an artery split . . .of course the image indeed looks like that !

It was indeed an absent left main.  Also called as separate origin of LAD and RCA.

Note : There can be three  types of absent  left main.

  • LAD and LCX from same ostia on the left coronary sinus*
  • LAD and LCX separate  ostia but both from same sinus**
  • LAD from left coronary sinus, LCX from right sided sinus (Probably the  common type )

* Some books mention about a left main of 0 -5mm .

** Very difficult to delineate and is rare

Zero  mm  left main is nothing but  single  ostial origin of both LAD and LCX. A very short left main , say 1 0r 2 mm will practically mimic an absent left main.

Here is the  the dynamic angio image. It is  surprising how a catheter in left sinus is able to visualise the LCX from right sinus so well !

Note the separate origin of LAD and LCX.The LCX was originating near the right sinus.It is intriguing to note even though they originate in different sinuses , the main stem of LAD and LCX wants to maintain a close parallel relation.

 

 

Advantages of having  absent left main .

  • It requires no great brains  ,  to predict  the above patient is  immune  to  develop  Left main  or true bifurcation disease
  • Sudden death is  presumed to be less common in this population.

Implications for interventional cardiologists

Guiding catheter selection and positioning could be difficult.

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Manuals are not only for doctors . There are few heart  maintenance manuals for patients as well.

This one from Philadelphia ,  is worth reading and of-course  following  thereafter  !

 

Some books can be as effective as CABG or PCI .

This  one is definitely in that league  . . .

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