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Posts Tagged ‘red vs white clot’

The news that wasn’t . It is January 1 st 2016 .

NBC reports from Karolinska ,Sweden , Heparin  the wonder drug  has been reclassified as a thrombolytic agent and Jay Maclean  who doscovered this drug in 1916  is awarded the Nobel prize in Medicine posthumously on the 100th  anniversary of  discovery  of  the glorius drug ! The entire Hopkins  campus at Baltimore has erupted into a  non stop party tonight !

Hopkins_hospital

The Majestic Hopkins at Baltimore  : This  monumental hospital is home to 18 Nobel Laureates in Medicine and Jay Maclean is the most famous for missing it !

 

And now to the True story

Heparin   the wonder  drug  was discovered by Medical student Jay Maclean in 1916 at the Jhon Hopkins when the rest of the world was   fighting the  world war 1 . It was separated from the cannine liver and the name Heparin was coined by Maclean’s Guide at Hopkins  William Henry Howell . Even though it was invented early  it was available for human use only in 1936  when Swedish company Vitrum AB produced it .Since then   It has a very distinguished career and still going strong after 100 years.

The only regret is Dr Maclean  narrowly missed  the  Noble prize for this great invention .I still believe he should  get it on its 100th   anniversary  in 2016.

A partial  “curriculum vitae”  of Heparin.

Heparin is an  Anti-thrombin 3 agonist .It blocks the pro thrombotic cascade and hence a powerful anticoagulant. Further ,it completely tilts the balance towards fibrinolytic  system.Hence the natural forces take over and  start dissolving the thrombus  in due course.

So Heparin is an indirect thrombolytic agent .No second thoughts on this.

But a century old teaching  goes like this  . . .

Heparin prevents fresh clot formation . . . but it do not have any action on already formed clots “

What do you infer from this statement . Do you agree ?

Role of Heparin in real clinical scenario

Heparin is the key drug in all acute coronary syndromes when the  coronary artery goes for sudden thrombosis . An un estimated one  million prescriptions are done every day world wide for this indication alone.

(*And mind you it does have a  significant  impact  on already formed thrombus as well ! Ref : HEAP Pilot  study  )

Apart from this.

1. Heparin dissolves post MI LV  apical clot over a period of  few  weeks.
2.Heparin is very effective in most cases of sub-massive pulmonary embolism
3.Heparin infusion has opened up many near total coronary occlusion
4.Heparin clears the micro vascular from thrombotic debri in lungs in CTEPH.
5.Heparin dissolves  deep vein thrombosis
6.Heparin almost result in complete cure and clears cortical venous thrombosis

7.Heparin is exceedingly successful in clearing   thrombosis in placental micro-circulation (APLS) which  threatens the  fetus with IUGR.

Al these clinical events are well documented and well appreciated.

Still we feel awkward to call the heparin as thrombolytic agent

Why ?
It is almost a  scientific non- sense .We think a thrombolytic should  show it’s action in vivo in the lab and it should shrink the clot on a petri dish !  What a wrong  mind set ! We have  tell-tale evidence  for heparin’s  magic act of vanishing clots   inside the human vascular tree (However organized  it may be ! ) .

I struggle to understand  , why  our scientific  mind does not want to give credit to a drug  which does a neat job of  dissolving  clots  through its  indirect action . Is it a curious bias  ?  or is it an act of  ignorance  or  just a nomenclature  error  in the  foundations of therapeutic  pharmacology ?

At this point one should  realise  streptokinase  too does not act directly on the clot.It acts indirectly through a TPA-enzyme complex.So can we call it an  non thrombolytic agent ?

Final message

  • Heparin is indeed a thrombolytic agent , through  a chain  of action and reaction  which  it confers to the naturally occurring lytic system.
  • In vivo ,this  indirect  lytic action can be  powerful than some of the direct acting thrombolytic agents .Not only that, it lacks the side effects  vested with direct  lytics.
  • The only issue is  , heparin is a slowly acting indirect thrombolytic it has to be given long-term or on an infusion .
  • It is right time the pharmacologists  and nomenclature authorities  include heparin as indirect thrombolytic drugs.

Read further

Heparin a forgotten Hero

 

Reference

1.High Dose Bolus Heparin as Initial Therapy Before Primary Angioplasty for Acute Myocardial Infarction: Results of the Heparin in Early Patency (HEAP) Pilot Study Freek W.A Verheugt,  Aylee Liem, Felix Zijlstra,J Am Coll Cardiol. 1998;31(2):289-293.

3.Esteves  FP, Braga  JC, Latado  A; Confirmation that heparin is an alternative to promote early reperfusion in acute myocardial infarction. the CHEAPER study [abstract]. Circulation. 94 (Suppl I) 1996:I-553

 

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