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 !
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
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 ?
- 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.
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 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