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Posts Tagged ‘time window for pulmoanry thromolysis’

Preamble

The much published TRANSFER -AMI study  has few important queries to ponder about.It was supposed to test the role of routine PCI following  thrombolysis. In other words it compared  rescue only strategy with routine strategy.The caveat is , even among  failed thrombolysis, the   rescue strategy has not convincingly proven superior to medical management  (if the time is lapsed ) as much of the damage is done .

In essence , Acute MI is  more about time management than drug or cath lab management

  1. Why the 67 % of  standard therapy cohort underwent PCI. Technically , you are supposed to transfer for rescue only if there is a  failed thrombolysis ?That is the standard approach , if  most of the cases are any way land up in cath lab , then you are trying to compare two similar groups .
  2. Why the rate of   failed thrombolyis with TNK-TPA in both arms not disclosed ?
  3. How can a 92% of study population be in class 1 Killip still considered to be high risk group ?
  4. Why the recurrent ischemia  was very vaguely  defined and still included and clubbed with primary end point along with deaths. If only recurrent ischemia was removed from primary end point . . .this study will straight away land in a regret bin.
  5. Why there were 6 additional deaths at 30 days  in routine early  PCI group ,  What was he cause of death ? Mind you these deaths have happened in a 92 %  Killip class  one cohort . Is it  not important ? The trend looks vitally   significant .We can not afford take refuge under a false  statistical roof .
  6. How many patients died or  developed MI  because of the early PCI in-spite of having  successful thrombolysis.This again could be vital . Complications during intervention  for a failed thrombolysis may be acceptable. While ,complications , when we try to  improve upon the already  successful thrombolysis is simply not acceptable .

Will the investigators share their experience ?

Finally

Why the title of the paper says it is about “Routine angioplasty” and  the conclusion emphasizes  it is indeed   “high risk subsets ofangioplasty” (While the study itself involves a 92 %  least risk Killip class 1 ) .  Why this double dose of confusion ?  (Is it deliberate  ! Which i think is unlikely )

NEJM please take note of this  . . .

All that glitters  are  not natural glitter . . .some are made to glitter !

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Acute massive  pulmonary embolism is a dreaded medical  emergency  . In the past,  surgical embolectomy was the main option . Now , we have thrombolysis as a viable option.But , it does not work in all cases.* (90% success ?). It is critical to evaluate the success of thrombolyis , before embarking upon rescue embolectomy.

As it is often in critical care  medicine , this decision making is not easy .

The key question is how long , we shall wait before labeling  thrombolysis a failure !

In-fact , premature  assessment is the commonest cause for failed thrombolysis. True failure is different from deemed to be a  failure . This  is often related  to  , lack of patience  among  the   members of  treating team . Unlike acute MI ,there is not a  strict time window to  follow .The issue hear is ,  not lung salvage but  restoring VP/VQ and  dead space ventilation . The assessment is made , by clinical ,   MDCT ,Echo  parameters.

When there is difficulty in judging success , clinical parameters will prevail over medical images !

 

Key clinical parameters for monitoring

  • Heart rate
  • Saturation
  • Blood pressure

There are  four  options  available to manage in  failed pulmonary thrombolysis.

1.Emergency embolectomy in an unstable patient *

2.Elective , planned embolectomy  in a sable patient **

3.Repeat thrombolysis ***

4.Continue Intensive heparin regimen  for up to a minimum of   72hours  and up to a week .

*  Dismal outcome .

** Best option (Ironically,  these are the  patients , who improve  with medical  management , as well !)

***This is especially useful  when  partial success  is noted in a stable patient . ( For rescue thrombolysis it is  logical tom use TPA if SK was used initially and vice versa.) The logic here is the initial dose was  either insufficient or ineffective  to lyse the thrombus completely. If TPA is not available /or not affordable,  repeat SK can still be considered .It can be  safely administered within the 5 days of initial dose.

**** Least popular and considered inferior but has worked wonders in many .

How to manage a relatively  stable patient with a large thrombus load  in his pulmonary artery ?

Option number 3 could be tried. Prolonged  monitored heparin

What  are the surgeons concern about  management in failed pulmonary thromolysis ?

Every  surgeon( Especially  the  cardiac  surgeons)  loves  to operate in a stable patient . If you hand over  a case  for pulmonary  embolectomy  ,  with  sinking  O2 saturation  and  falling  blood pressure  ,the outcome can be  easily predicted !

Further, RV dysfunction  is notoriously known    for pump dependency  .  CT surgeons are vastly experienced   in  the intra operative tips and tricks of  managing  LV dysfunction (They may not be  in  so  in RV dysfunction !)

Bleeding risk  is also high especially  in the milieu of   intensive anticoagualtion and thrombolysis .

The mortality could be as high  as 30 % in many centers.

 

Final message

  • The incidence  of failed pulmonary thrombolysis  is  often subjected to the whims and fancies of treating physician  and the imaging modalities used.
  • Timing of assessment is critical .One need to give a long rope for medical management  , in spite of the urge , to do something more. .
  • Clinical improvement should be the main guiding force.
  • Normalisation of tachycardia   ,  improving  trend  of  o2 saturation(  >90-95%)  , regressing  RV size are useful parameters.
  • Thrombus load  detected by a repeat  CT scan  ,  need not be  the   sole guiding parameter.In -fact , mobilising these patients for CT scan by itself is fraught with a risk of  worsening the hypoxia.
  • The issue of  tackling the source of thrombus should  be addressed separately .Luckily, the same anticoagulant protocol takes care of this issue also. It is rarely a emergent issue.
  • Deploying an  IVC filter as an emergency procedure is a bigger controversy .At best , it is useful in few high risk individuals with high risk mobile ileo-femoral clots .
  • Finally, not every one can handle this  situation .Ideally such  patients  should be  to be  shifted to a well established cardiac surgical  set up .

From Chest journal

http://chestjournal.chestpubs.org/content/129/4/1043.full.pdf+html

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