The funny logics in cardiology :The dichotomy of thrombolysis in Ischemic stroke and STEMI
Posted Mar 28 2010 11:42am
Thrombolytic therapy is the specific therapy for Ischemic stroke , when administered in less than 3 hours and has proven to save lives and brain .The only issue is , we need a 100% exclusion of hemorrhagic stroke by a CT/MRI. The mechanism of action of thrombolytic agent is simple .It lyses cerebral thrombosis and makes way for sustained reperfusion and arrest or even reverse the ischemic damage to neurones .
And now , let us see , how we perceive the same therapy in a patient with a history of recent ischemic stroke with an acute STEMI .
The issue is two fold.
He needs urgent myocardial salvage in the form of thrombolysis or PCI .
The thrombolysis or PCI should not worsen the cerebral infarct.
According to most standard literature thrombolytic therapy is an absolute contraindication in a patient with STEMI and recent history of ischemic stroke (<3 months )
The term absolute means ‘it is medical crime” to give TPA or Streptokinase.
How is it possible when the same drug is projected a savior in acute ischemic neurological emergencies and be dangerous when administered few months later in an evolved ischemic stroke ?
The major reasoning against thrombolysis in recent stroke is the potential concern for converting an indolent ischemic infarct into hemorrhagic infarct in a patient who may start bleeding into brain.
This is highly conjectural as a previous history ischemic stroke in no way increases the bleeding risk .Conversion of ischemic to hemorrhagic infarct tend to occur in the very early hours of acute stroke (not weeks later) .This could be part of calcium induced reperfusion injury .
The issue become further complicated with our thinking pattern,as we get a wrong message
“If thrombolysios is contraindicated in STEMI it becomes an automatic indication for a primary PCI “
How safe is PCI in a patient with a previous history of ischemic stroke ?
An emergency PCI in a patient who is expected to have widespread cerebral carotid , and peripheral vascular disease is fraught with added hazard.
Aortic arch manipulation and aortic valve atherosclerotic changes might increase a risk of another stroke.
The drug we administer during PCI are not innocuous ones . Aspirin , Heparin, clopidogrel (sometimes even 2b 3a!) will make sure , the risk of converting the ischemic infarct into hemorrhagic infarct remain at dangerous levels . This ridicules the the very logic of PCI being preferred over thrombolysis in such situations .
So it is not an easy decision to do primary PCI in an elderly patient with STEMI and a recent CVA. It is only a mirage of medical intellectualism and the blind following of unscrutinized scientific literature that determine many of the decision making in cardiology .
The argument here is in a patient with evolved or even uncomplicated ischemic stroke thrombolysis can be safely administered irrespective of the age of stroke. .This is contrary to the published literature.Let us not make unethical practice against scientific literature but let us also understand it is unethical not to realise many of the so called scientific evidence that is merely speculative.I request the neurologists and cardiologists give their input on the issue
As far as i have searched the superiority or inferiority of thrombolysis vs PCI in recent ischemic CVA has never been compared one to one. The fact may be , such a study is never possible in the future .But it seems PCI has won the trial without a trial .
How many deaths have happened due to worsening stroke after thrombolysis ?
How safe is a combination of aspirin, heparin and clopidogrel
How shall we decide about thrombolysis in these situations of STEMI and recent CVA) depending upon the
Age of CVA
Location of cerebral infarct
Size of the infarct
Residual neurological deficit
It may be prudent to redefine the indication for thrombolysis and PCI in a patient with history of recent or remote stroke.
It is logical to assess the potential risk of converting the ischemic cerebral infarct into hemorrhagic infarct.
It is expected only large infarct in vital locations need to be feared upon for this complication
All small healed cerebral infarct need not be worried about reactivation.
How to asses the healing of cerebral infarct?
The healing and gliosis is highly dependent on individual response to inflammation. Some heal within weeks. Neo vascularisation within the necrtoic area may get hyperpermiable .These are very speculative concerns. In all probability the risk of converting a ischemic necrosis into hemorrhagic necrosis is less than a percentage .The 3 months time for fixed for infarct healing is an arbitrary one
How good is MRI to predict a healed infarct from nonhealed infarct ?
As of now, we have no good tools to identify the safe infarcts that can withstand intensive anticoagulation or even thrombolysis .If the imaging techniques improve we may able to predict complete gliosis and the vascularisation of cerebral scars.
Post blog query
How to manage an elderly man with STEMI in a patient with recent ischemic stroke ?
A.Take him to cath lab and do primary PCI
B.Thrombolyse with TPA or Streptokinase
C.Just observe and manage with Heparin*
Answer : Any of the above can be correct answer .
If we still think the answer is only “A” great reforms need to be done in medical science . . .
*Another important option for STEMI and recent stroke (Perceived as inferior form of management of STEMI !)
An important option is , neither thrombolysis nor PCI just simple heparin for STEMI in these high risk individuals .This simple treatment has saved many lives .
See : Related video forgotten concepts in cardiology
In this world of gross approximations and perceived fears it may be reasonable to shift the indication of thrombolysis for STEMI( and recent stroke ) from absolute to relative contraindication.
This is especailly true , as many of the junior physicians in the learning curve may take it as granted in the management of STEMI “If thrombolysis is contraindicated , then primary PCI must be indicated ” This again is aboslutely not true !