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Posts Tagged ‘primary pci’

When a culprit thrombus keep the  myocardium as hostage . . . don’t storm the coronary artery  indiscriminately   !

When a single gun men  keeps 100 innocent people as hostages , threatening their  lives, rescue mission should start .No can can afford to wait. But, without knowing  the  culprit’s true nature the process of rescue mission is always going to be tricky .There are so many instances Newton’s third law  was reversed , when reactions  evoke more chaos  than the index action.

In the recent world terrorist events ,  the  rescue missions  were so delicate and  it was very  unfortunate we  lost  many   innocent hostages !  The reasoning is ,there  is no way we can avoid these. I wonder is it really true ? !

rescue missionNot all culprit lesions  are true ones.They simply threaten  our myocardium with  thrombus and plaques  in various forms .Don’t show aggression to pseudo threats  you may  ultimately end up with more damage.(What I call as crazy culprits!)

(  Read here , why unstable angina even though thrombus is sitting right inside the coronary artery attempting to lyse it causes more  damage !)

After thought

Iam sure ,bulk of  the Interventionists wouldn’t agree with this thought . They would decry , watching a person  silently when the myocardium  is on  fire is a serious crime !

But . . . we  need to  remember the process of extinguishing  the fire  with some more fire arms is a delicate game played in undefined  philosophical turf.

The only way to introspect  such events in life is , to accept any eventuality    arising out of “not pursuing”  a  presumed rescue mission with vigor. No need to be guilty about that,after all , it can be a myth !

Modern human cognition , growing with a staple  scientific  feed  on a 24/7  basis  is  unlikely to realise , restraint can be an effective tool  even in critical moments !

Oh,is all that I have  scribbled so far  is just a repetition  of 1000 year concept of  “Primum non nocere”

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Interventional cardiologist extraordinary  cath lab tips invasive great

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Multivessel PCI during acute STEMI is forbidden except in cardiogenic  shock . (or in some very unstable patients without cardiogenic shock)

The reason

  • During acute MI   hemodynamics  are precariously balanced.We do not know yet how  emergency multivessel plasty alters this .
  • Our  initial aim should be   confined to myocardial salvage in the IRA . Total myocardial revascularization is niether  the  priority nor its desirable.
  • The more  time  you spend  within the inflamed coronary artery , more its  hazardous.
  • Multiple stenting  is prone for thrombus   and  migration  into side branch .
  • Stent opposition is sub optimal in many thrombus infested lesions.

Still  . . .  in real world it is extremely difficult to curtail the urge to stent  all eligible lesion during primary PCI !

multivessel angioplasy during stemi

How to avoid it ? 

If the patient is poor or the insurance limit is low , the issue  of multi vessel stenting does not arise at all  !

Always  ignore  complex  non IRA lesions  during primary  PCI. Be happy if a non IRA has a bifurcation lesion !

Still , some lovely looking lesions in non IRA  would be  tempting  and inviting .  Indulge at your own risk !

* Please remember if  the proximal  LAD  has a non IRA lesion , it may be sensible to attempt  simultaneous revascularisation even if the patient is stable !

Other unrealistic advice

  • Keep the professional fee and other benefits   fixed whether  we do a single or multiple   vessel stenting (Realise  . . .  surgeons do not charge more for a  4  vessel by-pass graft  than a single  ! )
  • Keep the current AHA/ACC/ESC guidelines pasted right next to the fluroscopy monitor .
  • Ask your subordinates to repeatedly caution   you  about the possible  excesses and ask them to wave a red flag !
  • You may  empower the   senior staff nurse   with a veto power  to shut off the cath lab once IRA plasty is  completed and the patient  is stable.
  • In extreme  situations , keep a cath  marshal ready to manually evacuate  the primary operator  from cath lab !

Reference

multivessel angioplasty during stemi

ACC GUIDELINES FOR STEMI 2013

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For STEMI management there are  6 management protocols available

  1. Thrombolysis
  2. Primary PCI
  3. Rescue PCI
  4. Facilitated PCI
  5. Pharmaco -Invasive approach
  6. CABG

*CABG is rarely used except in  severe mechanical complication.

There is some  issues in differentiating  facilitated PCI and  Pharmaco Invasive Approach.

What do we facilitate ? How we do it ?

PCI in acute STEMI is done in a thrombotic milleu. So we get sub optimal results .Hence to facilitate it we try using

either 2B-3A antagonists, Newer Heparins, or even thrombolytic agents before submitting them for PCI

Where is this facilitation done ?

Facilitated PCI is done in small hospitals where  there  is no cath lab or cath lab is available only during office hours.

Facilitation can be done in either in same hospital or on the way to big hospital

Is there a time window to start  this ?

The main aim was to was to facilitate the PCI .Hence time window was not considered vital in few studies (Wrongly though !) ideally it should be started as early as the first contact . Since facilitation can be started earlier the time window is 0-24 hours .

What happened to the concept of f-PCI ?

It died a premature death  and  last rites were  completed when the FINNESE trial was out .

But it left behind a daughter concept ie in selected patients if the facilitation is done early , especially in those patients who are going to get the subsequent PCI late ,or in high risk individuals  , the initial  pharmacological facilitation* was indeed useful.)

*If  facilitation was with   fibrinolytic agents (Not 2a/2b )  .It is very important the benefits of facilitation is mainly  attributed to the time gain in achieving partial opening of IRA  making it more complete salvage of the subsequent PCI .

This aspect later on named as PIA .

Pharmaco- invasive approach(PIA)

We know p PCI is a race against time .We also  know fibrinolytic therapy  fares well in this race  but   pPCI  beats in   effectiveness  .

So what prevents us to combine the swiftness the fibrinolysis and the robustness of pPCI ?  That is  like getting the best of both world .( It is not that easy thing accomplish after all 1+1 in medicine is rarely 2 !)

In it’s core principle it  is same as f-PCI . But facilitation is done only with fibrinolytic agent (Not 2B-3A) . Pharmaco Invasive strategy can be started in any small hospital/ In the ambulance /. It  is routinely followed by PCI whether the initial thrombolysis is successful or not . PIA should not be done before 3 hours window if  a timely pPCI is feasible.  Hence PIA has a typical time window of 3-24 hours .

Summary

f-PCI is combining  various anti-platelet and fibrinlytic strategy prior to PCI . It was found  to be useless if it is used routinely in all cases of pPCI. (Rather 2B-3A  was useful  if  only the facilitation was done within the cath lab to prevent procedure related issues) .Time window can be between 0-24h .

Pharmaco Invasive approach (PIA)   is actually a type of f-PCI where  fibrinolytic agents are used routinely which is followed by mandatory angiogram and PCI in all deserving cases.Many still  believe the facilitation in PIA is primarily accured in  shortening the   time to reperfusion  rather than altering the thrombus load and morphology  ! Time window is usually between 3-24 hours.

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Primary PCI is presumed to be the ultimate  , undisputed reperfusion  strategy  in STEMI .  Still , time and again one study or  other strips down  this   “Numero Uno”  status of pPCI  .  If it is really supreme ,  such awkward  situation shouldn’t arise  too often . More importantly , the  major reason for  dubious real world record of  pPCI  goes beyond  the time and logistic factors (which is considered the only issue  for pPCI by most interventionist ! ) There is something more to it that is invisible ! (Is it the no reflow ?)

The nearly flawless study from Belgium ( STREAM Just released in ACC 2013/Sanfransisco ) , pre-hopsital or early fibrinolysis has proven to be superior in the prevention major end points at 30 days .

  1. Death
  2. Re-infarction
  3. CHF

STREAM STUDY NEJM PRIMARY PCI VS FIBRINOLYSIS

The major surprise was pre-hospital  fibrinolysis  showed less  incidence of cardiogenic shock . ( pPCI

group had more of this ( 4.4 VS 5.9 %  in STREAM )

Now . . .  shall I make a provocative statement ?

while pPCI may be treatment of choice for cardiogenic shock . . . but it may  also confer a risk of cardiogenic shock in otherwise low risk MI !

Caution  and  conclusion

STREAM population applies strictly to 1 to 3 hour time window . It does not apply to either before or after that ! Simply put,we do not have  guts to compare fibrinolysis and pPCI  in patients who arrive  within one hour into a facility where 24 hour cath lab facility is available .  We call it unethical to do a study like that !  I personally feel it is really unethical  if we do not do a study in this time frame . The reasoning is  simple and very personal .In a  large  Government  hospital   where  we do not have primary PCI program  our net mortality for STEMI never exceeded 7-8 %  over a period of 10 years  , Which  is almost at par with global data on pPCI. (Our door to needle time is an unbelivebale  8-12 minutes ! that  too only streptokinase !)

Adding Further controversy

pPCI  is indeed a superior reperfusion strategy . No one can dispute that .But its superiority  is not  realised  in  every patient  who gets it.  The benefits are accrued if and only if it is  used most judiciously . In Low risk , small regional  , branch vessel STEMI ,  pPCI has never been  shown superior . It is well recognised ,  upto 15 % of STEMI is likely to spontaneously abort or experience very good spontaneous recannalisation . By rushing these  patients very early into cath lab pPCI   meddles with the natural anti fibrinolytic mechanisms . It is this population who  invite all the procedural hazards. .

Is this the reason STREAM had  more  cardiogenic shocks in pPCI limb ?

I think STREAM has  strengthened the case in favor of fibrinolysis in this  ever ending debate .

I would  seriously believe  pPCI is hanging it’s superiority over fibrinolysis with a wafer thin mortality advantage . pPCI may  not be recommended in a routine fashion to all STEMI  population even if they arrive within 6 hours and able to perform the plasty fast .  Science is   . . .  after all . . .  continuing  confrontations with our  assumptions !

Counter point

STREAM is not an exclusive study comparing fibrinolysis and PCI . It is a  study comparing   Pharmaco Invasive approach vs  pure invasive approach . 80 %  of patients in the  fibrinolytic limb ultimately received PCI and  stenting . It simply doesnot make sense to conclude fibrinolysis is superior to PCI . Most of the beneficial  effects on 30 day outcome may reflect the timely PCI  in the lytic group.

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A patient with  extensive anterior STEMI  presented 18 hours  after onset of  chest pain . He  was  other wise stable and free from angina but had persistent ST elevation (5mm in V 1 to V 5 ). He had a  total occlusion of LAD  with TIMI zero  flow . He had a  tight PDA lesion  as well . A bed side echo revealed LV EF  of 50% . The septum was hypo-kinetic but did not appear severely dysfunctional .

So , it was decided to open up the LAD. The moment  LAD was opened he developed severe acute LVF  /   flash pulmonary edema   .  Even after a 30 minutes of  heart (Fire )  fighting  he could not be resuscitated .

What is the mechanism of death here ? Expert  STEMI interventionist  from core  labs  may answer this !

An acute ischemic MR with myocardial disruption was suggested . Why it  was triggered after opening the IRA ?

Three mechanisms were discussed

  1. Re-perfusion injury
  2. Collateral  damage
  3. Physiological  de-stabilisation of  Contra -Lateral lesion (Remote lesions )

Re-perfusion Injury ?  How relevant it is in cath lab ?

Is re-perfusion injury  electrical  ,  mechanical or  both ?

In this particular patient even though there was a total LAD occlusion , the segments supplied   by  the LAD  was partially functional and  it was contributing to LV  pump function.  The moment  a trickle of   flow was established  , some thing happened and the whatever  little mechanical function  his LV  had  was also interrupted  . The LV came to standstill and the patient died .

If re-perfusion Injury is  simply an   electrical  event   like VF ,  it can be resuscitated . If it is mechanical  outcome is bad ! This is not a new concept  . It is  part of the  once famous  concept called myocardial stunning . There are  lots of reasons   for stunning  to be a  clinically relevant phenomenon .Unfortunately   if any cardiologist talks about it in 2012 ,  he is at risk of  labeled  as old fashioned !

Collateral damage.

One more mechanism which we feel that  might have contributed to death here  is   the  “collateral damage” .(This is not cross fire !)

We know collaterals can be recruited within 12 hours in many STEMI patients . In some  it can even salvage  significant mass of  myocardium . The acute collaterals to LAD may be interrupted  during primary PCI . Once you poke the lesion the coronary  vascular  bed which had dilated  (as a response to total occlusion ) may react with inappropriate vasoconstriction . This raises the local hydrostatic pressure (Myocardial edema)  and further impede  the   incoming  micro collateral flow . This a very  critical time  for the myocardium  where antegrade and retrograde flow are kept in a fine balance .

Interference with remote lesion Hemodynamics .

Another possibility  is  the  opening the  LAD lesion some how  impact on remote lesional  flow as well (PDA  in this patient  )

Please remember ,

Even a transient hypo- tension can have  devastating effect in  the  hemo -dynamics   of  non IRA  territory  especially if it harbors a critical lesion !

Final message

Coming to the title question  , Is no – flow better than  slow- flow in late presenters of STEMI ?

Common sense dictates whenever  an artery is obstructed  just get rid of it.  When  it  comes to the heart it must be done in an urgent basis That is the essence of primary angioplasty  . . .  agreed . But in this  patient  I believe ,  the  common sense  was proved wrong !

Truths are always hidden.  The  science of  myocardial re-perfusion is a perfect example . We need to learn a lot still !

This I  call as  Para cardiology : Heart  facts without  evidence !

Counter point

One may argue this   is an  exceptional case  in STEMI  intervention. Don’t  hype   exceptions  and undermine the importance of a great concept ! Exceptions  and rules  are directly related to our  experience  we have accrued.  Exceptions are the great  knowledge substrates  and help  crack  medical  mysteries !

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The key word for  successful  primary PCI  is

  •  Suction &  Aspiration of thrombus  with   micro catheters like  export catheters
  • One can do away with a stent during primary PCI but can never do away aspiration
  • Distal protection as concept is rapidly dying out as we aim to remove all the thrombus .

Tips for effective thrombus aspiration

  • Apply continuous negative pressure once catheter reaches the thrombus do not release  it till you enter back into the guide.
  • Make sure  you are sucking only  blood  products  not the  endothelium
  • Watch out for  side branch spill over.
  • 7F sheath 7F catheter ideal for aspirating  with a  micro catheter
  • Please be informed some thrombus require more negative pressure especially  in the late  presenters of STEMI

* During dire emergency when you do not have a specialized suction catheter do not hesitate to push  even a diagnostic catheter into the coronary .We have  saved few lives !

Crazy   questions  in primary PCI  ( or Is  it futuristic )

Can we connect the suction apparatus into LAD micro catheter ?

Do we have camera guided suction catheter ?

Can you flush the thrombus if you are not succeeding in aspiration ?

Is ultrasonic desiccation  of thrombus possible ?

Acknowledgement

Some of the tips were  gathered from the recently concluded  India Live  2012  conference   in New Delhi .

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