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Posts Tagged ‘pPCI’

How often you assess the success of Primary PCI with degree of  ST segment regression or resolution ?

I posed this query to a  freshly hatched , Intelligent and energetic cardiologist in an upscale dedicated heart care center.

He said, “No, we don’t .We always go with TIMI flow in IRA .TIMI 3 flow with less than 30% narrowing of IRA is success, that’s it ! He continued ,very often ,we don’t even Insist to take serial ECGs after the procedure .  . . forget about analysing ST segment  !  His body language seemed to suggest,  he didn’t expect such a question (Silly !)  from me , talking about ECG  in this era of hyper Interventionism where we literally live within the coronary artery !

What a grave error in coronary cognition ?  . . . thats commited  day in day out of cath lab  all over the globe !

TIMI flows across IRA lesion tell  more about epicardial patency while the humble ECG  reveals the true myocardial reperfusion.

So ,which will you use for assessment for successful reperfusion ? Ideally both , right !

But , as of 2017 ST segment regression is not considered worthy to  define success of pPCI  by the all powerful world scientific cardiology community .This is unfortunate (Or Intentional ?) we have  ignored  this Inspite periodic research papers showing the importance of the same.  (Link to this land mark Brodie BR AJC 2005)

Do you know , none of the  trials that celebrated the superiority of primary PCI in the last two decades used  ST segment criteria. But then ,we realised much later even TIMI 3 flow can have near zero myocardial perfusion. So ,can we now say all these trials are invalid ?

We also never bothered to include no reflow as a liability during pPCI. We have enough data to say even restored No reflow during pPCI has worrying long-term outcome  as reocclusion and tissue level perfusion is dismal .(Can we call it a pPCI failure equivalent ?) This is because the Cocktail  of anti no-reflow drug  we administer often give us a momentary satisfaction with transient myocardial blushes ! (Only to occlude minutes later as the patient is wheeled out of cath lab .We will never ever know how often this happens  !) This is because , microvascular bed integrity is notoriously unpredictable and defies the conventional salvage time window . We have seen patients with ultrafast pPCI ending up with severe LV dysfunction.

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Final message

If you apply the ST regression criteria by 90* minutes after  pPCI (as we do for lysis ) the true success rate of pPCI will emerge .My prediction would be , if you do that routinely  the hype of perceived superiority of pPCI might go down the drain (At Least in all low risk STEMI ! ) Let us do a large-scale trial comparing ST regression with TIMI flows, blushes ,frame counts etc and rediscover the true face of our beleaguered coronary microcirculatory sense !

*In fact ST regression should occur much early with pPCI than lysis (May be 10 minutes after restoring IRA patency ! )

Post-ample and a Quiz !

If coronary thrombus laden IRA  is the chief culprit in STEMI battle field , Why is that Immediate , routine aspiration of thrombus in the ground zero is counter productive ?

That’s what the sophisticated mega trials of coronary thrombus  TASTE, TOTAL revealed.  I’m looking for an answer !

Reference

 

Counter point (and adding more confusion !)

Surprisingly , a Danish(DANAMI)  study showed  ST regression may not be Important in pPCI .This appears curious , especially when it suggests , ST segment regression didn’t occur because of more complete revascularisation by PCI !

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Soft skills in pPCI 

Experience  would tell  us only about 70-80 % of STEMI are truly eligible for a  good  quality pPCI .(Multivessel CAD, Complex bifurcation lesion, difficulty in identifying IRA, No IRA-sapsms , complete spontaneous reperfusion )  The remaining 20-30 %  should , logically  be included in the failed pPCI category .This fact is largely concealed in the literature .

Beware of huge thrombus load in every patient with STEMI .The  contribution of  mechanical occlusion  vs thrombus  (in the total occlusion )  is the single most important factor in determining the intervention strategy.

Deploying a stent in a poorly  prepared (debrided of thrombus  ) lesion confers  further continuous  risk of a STEMI .Stents smartly jail  even large thrombus against the coronary vessels and they release it into the lumen in a controlled fashion  and prolong  the  acute coronary  risk phases

If thrombus aspiration  does a neat job and establishes a good   flow , if the   lumen  appear   good , think twice or even thrice before deploying a stent .It is akin to stent a  zero % lesion and we know it is foolish to do that at any stretch of imagination .(Stenting has never been proven to convert a vulnerable ulcerated lesion into stable one )

IVUS, OCT are not the answer in the above situations  as we are dealing with  emergency coronary  fire fighting !

Of course the intensive anti-platelet   protocols , will take care of  potential after effects of the intra coronary contact sport we play  !    . But . . . there is a limit for every thing. So spend as little time as possible when attempting catheter based reperfusion during STEMI.

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Primary PCI (pPCI) is probably*  the   best modality in the management of STEMI .

( *Probably because ,    we  know “Time” ( fate !) is  still the  most crucial determinate of ultimate outcome of STEMI )

Any experienced interventional  cardiologist will be aware of the surprises  and difficulties  they encounter during primary PCI.

The pPCI  is all about  opening up the IRA rapidly and  wheel  out  the patient  from cath lab at the earliest.

But ,  ironically , an often  under- reported   issue  is the difficulty in  identifying IRA itself  !

One may wonder  , how this can happen ?

Following difficulties  can occur  in identifying IRA during  primary PCI*

(* There are some  hyper-talented  cardiologists who would never consider IRA recognition as an issue  .This article is not meant for them.)

The problems can range anything between the following   queries

  • Where is the IRA?
  • Is that the IRA?
  • No IRA ?
  • Multiple IRAs !

Angiographic encounters during  pPCI  and  IRA  trouble shooting .

  • When there is diffuse multivessel disease.
  • Thrombus vs  eccentric plaque  both  showing  intra luminal filling defect .
  • Thrombus spill over to adjacent branch or A mid LAD lesion with  stagnating thrombus extending to LCX ostium  mimicking two IRA
  • A bifurcation lesion with both LAD and LCX  ostial occlusion.
  • Multiple active looking  plaques with thrombus
  • STEMI in patients with preexisting CAD . Is it a CTO ?  ATO ? (Acute total occlusion ) A  CTO  ,which is  fed by collaterals from contralateral artery  ,  if this feeding vessel is  occluded even  partially ,  STEMI will occur in CTO territory . Here  , for rapid salvage you need to open the vessel that feeds the CTO territory.
  • Post CABG and post PCI form a special subset . Some times it is very difficult or even impossible   to label a graft as an IRA

Finally and most importantly  , when  there is no visible lesion in any of the coronary arteries   and look  near normal  !   Is that  no IRA  ?  or Wrong diagnosis of STEMI ?  Every one blinks  in cath lab . The consultant  howls the fellow to verify the ECG . Finally it may  well turn out to be an early  repolarisation  syndrome . These are wages we  often pay for the modernity !

How to approach  the situation when one is confused with  identifying the IRA ?

The good old ECG will come to  our  rescue sometimes. Realise in a multivessel CAD  , ECG is also vested with errors.

Echocardiography  rarely  gives a convincing answer to localise IRA. (Segmental overlap , preserved sub epicardial  contraction , residual ischemia all tend to confound )

Most confusions occur between LAD and  diagonal /LCX as there can be a huge overlap in the ECG territory  anterolateral segments

In a infero posterior STEMI, if  you have both  RCA  / LCX lesion and you wonder which  is the IRA  it is easy to solve by looking for RV involvement. (LCX lesions however dominant they are  . 99/100 times can not infarct the RV significantly  !)

If the lesion  is in PDA  the  issue is made simple.

Doing a primary PCI  blindly without knowing the IRA

This is  modern-day cardiology  at its scientific  low ! . Cardiologists  indulge in such  things much more commonly than one would imagine.

Probably  they would reason ,  it is safe to stent every vessel that is potentiality  an  IRA  , rather than  missing it. Though the concept of  multivessel stenting in STEMI   may help   patients with complicated MI ,  like pump failure ,  it generally increases   risk of primary PCI outcome in otherwise stable STEMI. Primary PCI procedure must be as short as possible. The other option is to do plain balloon angioplasty in less deserving vessels.

Important considerations  in the setting of complex multivessel CAD  during pPCI .

  1. Fall back on medical therapy
  2. Staged PCI
  3. Deferred or Immediate CABG
  4. Hybrid procedures like PCI  with CABG

Final message

IRA identification can  indeed be a difficult task  during primary PCI.  Sound knowledge and experience about coronary anatomy and its draining territories especially  in  the setting  of  multivessel  CAD  is essential to avoid errors.

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