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Archive for the ‘Cardiology -Interventional -PCI’ Category

Originally used in early 1990s,  self expanding coronary stents (Wall stent from Boston scientific )  subsequently lost interest because of delivery related issues. Many feel , it makes cardiologist judgment tentative and delivery system prevail over our hand skills. It is possible stents can longitudinally jump with high radial force making a geographical miss more likely.While it could be true with any technique till we master it, one should recall ,most endo-vascular work other than coronary still involve self expandable techniques.

Balloon expandable  stent is ruling the PCI field  for more than 2 decades. There has been recent surge of interest in the self expanding  technique and it could make a great difference in the PCI arena provided we take the proper cues.

Self expanding stents have some unique advantage

  • It has  high radial force.
  • Approximation with lesion is best
  • It tends to take the shape of the vessel than any other stent
  • Since the mal-opposition and gap between stent and vessel wall is minimal stent thrombosis is theoretically is  lower.

Where is self expanding stent useful ?

  • Ectatic and very irregular lesions
  • Bifurcation lesions where multi dimensional vessels with different shaped ostia converge.
  • Eccentric lesions (Non calcified) may be benefited by self expanding stents
  • Self expanding covered self (Is it available >)  may be the best bet for perforations and for thrombus  to be plastied against the wall.
  • In some small vessels PCI
  • Finally it may have a  role in primary PCI (APPOSITION 1 to 5 )

What are the self expanding stents available ?

  1.  Devax system   ( 2003)
  2.  Stentys
  3.  Radius (Boston scientific)
  4. Capella Sideguard.
  5. Cardiomind Sparrow
  6. vProtect luminal shield.

Final message

For some reason , self expanding stents were not tested widely  and  large scale data is not available. However ,  they are unique modalities in metal delivery and must be mastered and many patient subsets will be benefited by it. They are not obsolete yet, APPOSITION 5 study will answer some of the issues.

Reference

1. Agostoni P, Verheye S. Novel self-expanding stent system for enhanced provisional bifurcation stenting: examination by StentBoost and intravascular ultrasound. Catheter Cardiovasc Interv 2009;73:481
2.Jsselmuiden A, Verheye S. First report on the use of a novel self-expandable stent for treatment of ST elevation myocardial infarction. Catheter Cardiovasc Interv 2009;74:850
3.Verheye S1, Grube E, Ramcharitar S, Schofer JJ,.First-in-man (FIM) study of the Stentys bifurcation stent–30 days results.

EuroIntervention. 2009 Mar;4(5):566-71
4. van Geuns  R.-J., Tamburino  C., Fajadet  J.,  Self-expanding versus balloon-expandable stents in acute myocardial infarction: results from the APPOSITION II study: Self-expanding stents in ST-segment elevatation myocardial infarctiion. J Am Coll Cardiol Intv. 2012;5:1209-1219.

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A patient with near 90% LAD disease who had a significant TMT/EST positivity with no clinical angina  was  subjected to FFR by a scientific  cardiac physician. Since FFR was recorded as  .9 , he was adviced against a stent and sent home with drugs.

Now , in the  physiological assessment of a coronary lesion ,  which one you are going to trust , TMT positivity or FFR ?

FFR  measures trans-lesional pressure drop  by creating a artificial exercise physiology  in a particular coronary bed by injecting just one of coronary vasodilators  namely Adenosine. FFR assessment can never be considered truely  physiological .There has been huge discrepancy in the amount , rate and route of administration and the hyperemic response to Adenosine.

Final message

In a single vessel disease population , if TMT is positive the lesion is to be taken as significant, irrespective of FFR.(Provided Anemia and other systemic factors are excluded )

*Read this and get ready to get  confused further , single vessel disease with TMT positivity  doesn’t mean medical management is never an option .OMT ,(optimal medical therapy ) even though a battered concept is not yet dead for SVD !

 

 

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Every one talks about  coronary excesses ! It happens  both  in acute and chronic  fashion , not withstanding the inappropriately  understood  . . .   appropriately  released  guidelines  on inappropriateness ! The  burden  of coronary syndromes of the humanity, I am afraid would  include these man made excess as well !

I stumbled upon two  small  “gems ” in this other wise wild dark  cardiology literature  .One from Kamaer , Netherlands and other from  Escaned from Spain.

Both  talk about a  simple and logical modality in the management of STEMI . If bulk of the STEMI events are due to coronary thrombosis just tackle it  . No more  . . . no less” Stent only , if there is tight residual lesion.

1. From Amsterdam , Holland.

krammer thrombus aspiration alone priamry poba for stemi no stent

2.This one is from Spain.These studies I am sure , only a fraction of the interventional community would have read .Reason ? We are always hijacked by the moments of glamor ! I am just sharing them .hope few are benefited

primary POBA thrombus aspiration alone for stemi no stent stemithrombus aspiration alone for stemi no stent priamry pobaThese two studies with total number of 44 patients has a potential to redefine  the entire practice pattern of acute interventional coronary care.(Of course , if only , we are ready to make sense out of it !)

But , the concept will be heavily banished by strong visible and invisible forces   for the simple reason it suggests a true possibility  of knocking  out the role of  stent from acute STEMI arena.

When I discussed with my colleagues  for a large scale study  on isolated thrombus aspiration in STEMI , they told it  is not possible for ethical reasons !

I was amused , denying such a study is biggest ethical blow to the field interventional  cardiology !

Final message

Proof of concept does not require numbers .A study with less than 50 subjects  can be far superior than multi-centre ,multi-blinded , self steered ,peer reviewed largesse ! The truth of the study lies in the core consciousness  of people who do it , not in the numbers and exotic statistical methods !.

After all , one of the greatest medical study  was  done by James Lind  (Father of RCT) who discovered vitamin c as an antidote for scurvy,  with a hand full of sailors  while they crossed the Atlantic many centuries ago !

After thought

You say , thrombus aspiration is great , Why the hell , TAPAS , INFUSE AMI, and TASTE studies  confuse us regarding thrombus aspiration  ?

Don’t blame it on thrombus aspiration .We do it perfectly . It is because of what  we do after that ! We decorate the coronary lumen finally with a piece of metal cherry  undoing all the goodness of a great pudding !

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Aorto ostial  stenting requires extra caution and special technique. It always  worry us  what if  few mm of  metal might project into Aorta when we stent a RCA or left main ostium.

To  prevent this ,Merit- medical  has innovated a catheter that help us position the stent exactly at the ostial level .It is  done  with a help of an octopus like buttressing arm that support the aortic wall when the stent is deployed .

Watch the video.

 

Reference

Merit-medical 

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As the medical care advances  human care  has taken the back seat. It is said super specialists  read more and more about less and less ! In the  process they  fail to see the  patients  as a single biological unit  instead as collection of organs .

While  organs in turn are looked as  pile of data.Hence the  treatment they provide lack the soul !

In the prevailing circumstances , how do we ensure  modern medicine  does not interfere with  these vulnerable souls,either to live in peace or leave in peace ?

Medical Ethics

Image : Source and Courtesy of http://illuminationstudios.com

It appears doctors are not at fault . The system is  biased towards raw science .Highly trained  doctors are tied down by  both  true and pseudo  scientific Intellect .Often  times they are compelled to do some procedure or interventions  just to  justify  the  premier status of the hospital  .While few do it  to show off  their expertise or  to impress  their peers   others are simply bound by rigid and obsessive  protocols and guidelines . Few others do it  for the burning  desire  of  scientific accomplishment .

One can offer hundred reasons for doing a procedure . . . but we always struggle to justify  with a valid reason for not doing a investigation or  procedure !

In fact , the  concept of appropriateness  criteria came out with good intention .But , it had failed miserably.

The irony is  . . . we need to indulge in something to avoid something.

Example 1 If homocystiene and  hsCRP vanish from the CAD screening industry   Adiponectin and Vitamin D3 comes in with a thunderous applause like a new Hollywood movie  !

Example 2: In cath lab  for leaving alone an insignificant  coronary stenosis , we have to do  another procedure  called FFR to satisfy  scientific ego ! (I know one senior doctor , who left a 80% LAD  lesion for medical management without FFR ( with all his clinical acumen )  was ridiculed for being unscientific !)

Here is a recent perspective article NEJM has discussed  this  important issue that plague us

Why should big  Tertiary  teaching hospital  are  flooded  with super specialists  which by default shun basic human care ?

Read this article*

Super specialist tertiary care hospital NEJM

*The article I have quoted  may  not  be completely relevant here  . . . It  answers  few of the queries raised!

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Fractional flow reserve(FFR) is an  Intra coronary hemodynamic  parameter  promoted recently to assess the physiological impact of a coronary lesion . Though it sounds logically attractive the concept  is sailing in rough seas  .I am afraid FFR is drowning  a fairly useful tool of IVUS  along with it  !

Read this large study on FFR (JAMA June 2014) .It seems to suggest  FFR is a costly and unnecessary accessory in cath lab

Image

Critical thoughts on FFR

It adds time , money , and procedural risk*  to any given patient .The only possible use is to reduce the proliferating stent usage !But the  irony  is complete as we do our daily business in  modern cath suits .To negate  one indulgence we need to  need to indulge  in  another ! (Junk begets Junk !)

It reflects lack of courage on the part of cardiologists to advice medical management even in obvious low risk lesions !

It is unfortunate ,we need a scientific or  a pseudo scientific tool to lift up our sagging medical intellect !

 

* crossing  delicate and often complex lesions  without any major purpose is bad wisdom !
(more…)

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Many  readers  of this site might have wondered  , about a  series of biased articles  pulling down the  superiority of pPCI in STEMI.

This  French  study (FAST-MI) throws stunning data  from the real world. Initial Fibrinolysis* defeated pPCI in all aspects of coronary reperfusion !

FAST MI primary PCI  trialFAST MI primary PCI  trial 2

*When we say fibrinolysis arm it means Pharmaco -Invasive approach .Today our  brain  is irreversibly conditioned to believe standalone fibrinolysis is  forbidden in STEMI . (Which I strongly disagree!) I am sure, very soon another stunning study will unmask the truth about standalone fibrinolysis  as well !

Final message

  • The truth  is ,  pPCI is really a superior  modality in some of the complicated  subsets of STEMI that too if performed fast.
  • In all other situations Initial fibrinolysis will rule supreme !
  • pPCI is not an Innovation for mass consumption!
  • Hence, “the roof top call” for  pPCI for every STEMI is nether desirable nor feasible.

Now, we have this evidence from France (Which was well known to us a decade ago) As always , truth takes time to arrive , while falsehood can come instantly !

 

In 2014 , after two decades of celebration of pPCI  the flagship Circulation journal  throws this Editorial !

primary pci vs thromolysis debate fast study

 

 

 

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Modern  day cardiac scientists have legally defined a significant coronary  lesion as > 70 % obstruction. Unfortunately this rule is applicable more in  academic forums not in cath labs.

While the guidelines seem to be clear in chronic coronary syndromes , in ACS  the interventional strategies based on  severity of lesion is  not  clearly defined.

Many times  in a  recannalised coronary artery following STEMI  (Either  spontaneous  or pharmacological )  even a 10-20  % lesion is stented .(Mind you ,  coronary erosion  that  trigger  pure thrombotic  STEMI  will be stented by most  of the  proud  young cardiologists of today !) The guidelines conveniently  ignore this area  allowing  the cardiac physicians  to  indulge in the coronary exotica !

Is this logical ?

Why do you need to stent a successfully lysed coronary  lesion with TIMI 3 flow. ?(We do know , many  young infarcts have pure thrombotic STEMI with zero % lesion   (In India 40% of young STEMI has near normal CAG  )

This situation arises by an ill conceived concept called pharmaco- invasive approach where routine coronary angiogram is advocated even after successful thrombolysis  in patient  who is asymptomatic and complete salvage of myocardium has been achieved  by pharmacological means .

* The only way to prevent this excess  is to ban the  pharmaco -Invasive approach for  asymptomatic and apparently successful thrombolysis .(Better still  even CAG should be banned ! for  the  simple reason an inappropriate CAG  begets an Inappropriate PCI !)

A Narrow  gap  separates  Ignorance and  knowledge !

Does the  PCI  makes the  ill-fated site  less vulnerable   for future events  . . .  when compared to   well  re-cannlised native coronary artery with negligible lesion ?

The funny side of  cardiac science  can be appreciated , when  somebody  is implanting a latest generation stent for 10-20 % lesion  just because it is associated with an ACS ,  another would astutely   study  the significance of 70-80% lesion  by FFR  in  an adjacent lab !

 

 

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Pharmaco Invasive approach (PIA)  is the new mantra in the management of ACS.It simply means the intention to do PCI   should always  be the  driving force in every STEMI patient , whether the Initial lysis is successful or failed .

This concept is exclusively created  for centers where there is no cath lab (This would include  hospitals  with  inactive labs ,  cardiologist  team  who lack required expertise !)

What to do after lysis ?

  • If  the initial lysis has failed  “Rush” them  for an emergency  PCI.
  • If  Initial lysis is successful  “Send”  them for PCI in a  less emergent manner.

Generally the  time window for PIA is 3-24 hours.  In failed lysis  technically it could be as early as 1 hour as that is the time to assess the efficacy of initial lysis. (Of-course the theoretical transfer  time to be added )

Why the 3 hour period for PIA ?

We know routine   facilitated-PCI(f-PCI)  with various combinations of  fibrinolytics  and 2b -3a antagonists is a failed concept. (FINNESS )

One of  the primary reason for f-PCI to fail is , the  very narrow time window  between drug and balloon which somehow  end up in more hazard  (Needle -Balloon window)  .

If they are very close the harm is likely to be more ,still they have to be closer if lysis has failed .(This is the reason many old studies had depressing results with even with the  concept  of rescue PCI !)

Lytic agents and PCI  even though we assume to compliment each other real world evidence indicate they share a love hate relationship .

 

Beware, PIA is one form of facilitated  PCI.

If we agree routine  f-PCI is a failed concept we are in for real trouble. PIA indeed may  masquerade as f-PCI  if  you combine lytic and PCI in sequential fashion in a hurry !

My point of view is is a  successfully lysed STEMI should not be rushed to cath lab .If  he  some how reach the  cath lab ultra fast manner , it behaves like a  f-PCI and he is going  to harmed more !  by the current evidence base  isn’t ?

If the  inital lysis was successful , with a  less complex anatomy, it is  possible your PCI  that is going make the lesion more vulnerable.

(The other  issue is tied with flawed human instinct. One can’t stop with CAG in a PIA* .Interventional  cardiologists rarely have the courage to leave a well recannalised IRA  without PCI.)

**Still , you need to facilitate the PCI in complex intervention in  true rescue situation.That’s were we require the collective wisdom.

Assumptions galore in ACS

We have difficulty in  identifying true success and failure of lysis .Vagueness with which we make decisions  in CCUs and cath labs  , is exemplified by the following facts. Post thrombolysis , 40%  patients with persistent ST elevation are asymptomatic and 30 % of all those with complete  ST regression , still have occluded IRA.

We are also uncertain when do  the muscle  truly  die after a STEMI ! It is 6 hours in some, 12 in many, 24h  in few , 36 h in a lucky ones .The role  of collaterals, intermittent patency , individual variation  resistance to myocardial hypoxia injury cannot be  be quantified .

Final message

  • The importance of Needle to Balloon  time (NBT) time in PIA  is to be strongly emphasized.
  • This time can vary between 1-24 hours .But practically it will start from 3 hours .
  • The irony is , we have conflicting  engagement with time in PIA. We have to  strive for both narrowing as well as intentionally  prolonging this time window .
  • It has to be narrowed in true rescue situations and   optimally prolonged (Or is it indefinitely ! ) in non rescue situations !

After thought

Can we do pharmaco-Invasive approach(PIA)  in PCI capable center ?

  • Even in PCI capable centre one may get struck in proceeding with anticipated primary PCI for various reasons . If delay is anticipated we  have to fall back on thrombolysis .This we call as  unscheduled  or bail out  phamaco Invasive strategy .
  • Intentional PIA   in a PCI capable hospital for all low risk MI is also a viable and option .Never think  primary lysis   for STEMI  even if we  have lab ready is serious medial crime . After all , pPCI has a very  marginal benefits in if any in all low risk STEMI!

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Left main ostial lesion remains a  challenging task .A new stent design is  proposed here.

The lesion

Left main  ostial  stenting lesion003

The hardware 

left main ostial coronary stent drsvenkatesan

The technique

Left main  ostial  stenting lesion002

Final message

This thought came  when I  recently encountered a patient with a left main ostial  stent which was projecting well into aortic root .It is an open access patency ,whoever is capable of converting this idea  to a clinically applicable technique is welcome to proceed !

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