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Posts Tagged ‘ptca’

This paper is to  be presented in the the Forth coming   Annual CSI meet New Delhi  December 2012

Beware of Primary PCI : Is there a Low risk STEMI where  pPCI is potentially contraindicated ?

Venkatesan Sangareddi  . Department of cardiology  . Madras Medical college

Primary PCI has proven to be the best  option for management of STEMI . But it need to be done early,  by an experienced team , in a good facility . It is not the individual expertise that matters !  Any treatment , which has great therapeutic potential  also  carries a hazard . So , these treatments  must be used with caution.  Not every STEMI patient , carry a high risk for death.  In fact , the mortality  in some of the subsets of STEMI  can be as low as 1%. If , a  STEMI patient , with a likely 1% mortality is going to get a procedure with  3 – 4 % ,risk it should (And Must !) raise a validity question  But,this issue is rarely addressed in the interventional summits.

In a case pool of 56  randomly collected primary PCIs from various institutes , the outcome  of pPCI  was analysed .It is a retrospective , observational study .STEMI was graded as high risk when one of the following features  were present and it was “low risk” when none of the feature  was  present ( Second STEMI , Extensive  anterior MI , Class 3 /4 killip, An episode of VT/VF, Complete heart block, Diabetic individuals )  High risk STEMI  constituted 22 patients .The overall in hospital  mortality  was (5/56) 9 % In high risk STEMI it was (2/22 )9.5 % in low risk  STEMI it was 3/34 6.4 % .In the corresponding period 40 patients with STEMI who were treated by only thrombolysis or heparin (If beyond time window ) was used a control . 15 patients  were in high risk In the this group the  mortality in high  risk STEMI  was (3/15 )19% and low risk STEMI  there was nil mortality (0/25) 0% .

There was an unacceptable moratlity  with  pPCI  in the low risk STEMI which fared worse than even simple administration of heparin.These data reveal a dangerous fact , that is , primary PCI does not differentiate in the procedural  risk with reference to the patient profile it deals with .While , it dramatically reduce the risk in high risk STEMI It confers a astonishing risk to low risk STEMI .The exact cause for this risk is not known . Common sense would tell , pPCI is  expertise driven driven while thrombolysis is not .Our analysis also suggest bulk of early hazard of pPCI is also logistics related.

Primary PCI could be  cautiously and consciously avoided  in  patients with  low risk STEMI even if it is technically and academically indicated. This can have a great impact in the overall outcome of STEMI management.It is suggested every STEMI patient need to be risk stratified on arrival.(It is still a mystery , why we do this for NSTEMI and not in STEMI ) . A change in the current PCI guidelines to this effect is to be considered.

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We do come  across ,  even  senior  cardiologists , who  tend to undermine  the importance  of  poster  presentations in scientific  conferences   (I know a  few ,  who  ridicule it as well  ? ) .

                      Is  it not a meanly  job   for  a  cardiologist  to paste a  poster  and stand  beside  it  for hours  , waiting for scientifically motivated audience !

But , what really matter is the thoughts ,  concepts  and often the hard work   that brings  these  posters to  big league  conferences .

Please remember   abstract posters  must cross the hurdle of  the conference peer review  committee’s scrutiny . Often times   the poster arenas   has  launched  some crazy ideas  ,  transform  them to  great  discoveries.

If   only  , Gruentzig had shied  away from the poster  he famously  pasted on lawns of   ACC  , Annual scientific sessions ,Florida

1975     .  .  .  the    revolutionary  concept  of  PTCA   would still be  in utero  !

Final message

I argue the young  fellows in cardiology to send as many  scientific  abstracts as  possible   in their  national or international  meets  . This is  where the  the future of cardiology lies ! Simply don’t  bother about the critics  .

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Medical science has grown ( and growing )  in an  astonishing pace. Many of the  inventions  which were  considered as  major break throughs   have fallen on the wayside over the years . Of course ,  quite a few  withstood the test of time .

One of  the great inventions  of last century  is per-cutaneous interventions  inside the human coronary artery .

The concept was first conceived and executed by Andreas  Gruentzig  of  Germany in year 1977.  Now , at-least a  million PCIs  are done every year to tackle  CAD  with greatly  improved knowledge base, evidence ,  hardware,  techniques and expertise .

PTCA  is  an  invention worth a Nobel prize . . .well , that’s what we cardiologists feel. The Nobel committee  seems to think otherwise .

What could  be the reasons ?

  1. PTCA is  simply an extension of an old invention. Already the  inventors  of the  cadiac catheterization were  conferred with  Nobel prize (Forssman, Cournand,Richards)  . Hence , it is a sort of duplication of  invention . If Gruentzig is conferred a Nobel prize  the man who discovered the  coronary  stent (A plaque scaffolding device)  will  argue he too deserve  a  Nobel !
  2. What Gruentzig  did  was  in-fact a fundamental  human  response  by Instinct !  .When you encounter  a mechanical obstruction on the road   just try to overcome it . “Here is an obstruction impeding the blood flow , let  me  remove it”  . He did this  with  a wire and balloon . There is not much intellectual  innovation . It was  delivery of a mechanical force through a wire  .   But what the  Nobel  committee should take it to account is , he did this  in live human beating heart  and  cured of his illness most dramatically avoiding a need for surgery.
  3. Finally  comes the vital question. What is the impact of this invention in the health of mankind. ? How  many lives have been  saved when compared to other modalities to treat the   coronary artery disease ? *.This again is not convincingly answered  especially in    stable angina  , for which Geuentzig  originally developed this modality  . One popular argument  is , in terms of life saved and sufferings  relived oral rehydration  fluid  or penicillin  would beat PTCA most convincingly !

* Another possible reason is ,  the  Nobel medical committee is probably well aware of the  perennial  controversy  about  role of  Medicine vs Surgery vs PCI on the outcome   CAD  and  the  superiority of one over the other !

Final message

Whatever  be the reasoning  ,  Nobel committee has to  rethink .  Cardiologists  all over the world   would definitely  agree  if one man who have  made a  huge difference in their patient’s  life ,  it must be  Gruentzig  .

It is well-known  Nobel prize  is given  for path breaking  research that  break  new grounds like  decoding  cosmic mysteries ,  expansion of universe  , cell signalling ,  molecular mimicry  and the  stuff  like that .

Still ,  Gruentzig  definitely  deserves  a Nobel  solely  for  the novelty  in his  procedure  and in the process it helped  avoid  surgery in vast majority of heart patients.

Reference

http://www.nobelprizemedicine.org/

http://circ.ahajournals.org/content/93/9/1621.full

http://www.nobelprize.org/

Video

http://www.angioplasty.org/video/aghero.ram

http://www.angioplasty.org/video/agcomplex.ram

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This term is quiet often used in the  main stream cardiology journals  ,  in work places , conferences  , hospitals and even among lay persons . No body bothers to define this terminology.   What exactly this term means ?

It  may  not mean anything  . . . to most  of us  even  as the percentage of inappropriate angioplasty is steadily  increasing over the years .

Picture courtesey : Jupeter Images

What does the term  Inappropriate angioplasty  mean ?

(Choose the correct answer  . . . one or more  may be  true )

A.It simply  means doing  unnecessary angioplasties and has no major implication  to  any one.

B.A form of medical ignorance  or  an unethical act and should be strongly condemned.

C. An acceptable cardiology practice ,  need not be discouraged , as  it improves the quality of life of physicians !

D. A  sure act  of  “error by  commission”   that amounts to   medical negligence .

E.It is a decent term for a major  guideline violation

E. It can be  termed  as medical malpractice as it amounts to harming the patient with or without intention.

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When  PTCA was introduced  by Gruntzig  in 1977 the whole world was awestruck. All he did was . . . to dilate a coronary stenosis with a balloon. No scaffolding  was ever thought off at that time.  It was a huge achievement .   PCI version 1 was  performed for over  20  years in nearly a million  patients   . Till his death stenting  was  an unknown concept.

When the stents first came in,  it was first used with extreme caution .  From the days of  bail out stenting, it  has evolved  into provisional  stenting, elective stenting ,and  now  what is called  “mandatory stenting”

When  Greuentzig was able to  perfuse the obstructed coronary arteries  successfully  in thousands  of patients  in the 1980s,    with a simple balloon

. . . what is the difficulty for us  to replicate it  in 2011 ?

Unfortunately  advocates of POBA (Plain old balloon angioplasty) are considered  to be  un-scientiifc cardiologists or even carry a risk of labeled as quacks.

But please remember . . . POBA   is alive and doing well  too ,  in spite of the serious threat  it faces from the current generation interventionists  . It  will continue to have an  important role in  many  situations.

1.In patients with multivessel  disease while the  proximal lesion  deserve a stent  , POBA is preferred in distal lesions  to reduce the overall metal load .

2.POBA has a major role to play in Primary PCI .We need to realise  dying myocardium does not demand  for stents. It simply requires  quick and prompt restoration of  blood flow. POBA can achieve this with flying colors in most situations.

3. Further , stenting  may be  difficult in complex lesions   during primary PCI .Experience tells us , it  is  dangerous to prolong the primary PCI  procedure time. Here POBA is the only choice ,  may be assisted by thrombus aspiration. Stenting may be delayed or even avoided in many STEMI patients. . We know there is huge STEMI population with  pure thrombus with no atherosclerosis.

4.Patients  with  co morbid conditions , who are  likely to have a non cardiac surgery in the near future  and those who  can not take antiplatelet  drugs  POBA will score over BMS/DES.

5.Finally a POBA costs nothing . .All it requires is a stiff  balloon . In this recession prone world  and ever increasing incidence of  CAD  , POBA  could be the  answer.

6. Acute recoil in POBA (Sudden deaths in POBA is  a rare event !) are more of a perceived fear rather than a reality. It can be argued stents  are  primarily used  to make  cardiologists job easy and  comfortable.

7.Cost effectiveness of plain balloon verses stenting was never  properly tested .

Final message

When sudden deaths  due to subacute   thrombois in DES population   is accepted with all those attendant  pride . . . why not we accept a risk of  less sinister event  namely the  late onset restenosis with POBA.

This is a funny world . The DES fiasco is driving us towards stent less world and a bio degradable stent is already being projected as new savior.

Meanwhile no  one can kill POBA thats for sure !  It  will  ultimately   be reinvented  with another exotic study  soon !

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Reporting a coronary  angiogram  may look like child’s play  for most cardiologists. Many do it in less than a minute. (It goes something like this  90 % LAD , 30 % ostial OM1, 50 % mid RCA etc etc ) The famous and meticulous  classification of Ellis and Ambrose proposed  two  decades ago appear largely redundant.

In this review we shall  briefly  debate an eccentric plaque or lesion .

Pathological definition

Pathologically  an eccentric lesion  will have a disease free arc  within an  atherosclerotic lesion.If we apply this criteria most of the plaques appear to be eccentric.

Angiographic definition

In simple terms  eccentricity is  said to be present when the plaque  volume is three times more on one side when compared  to opposite side .

The incidence of eccentric lesion is largely under estimated.  It can be up to 40 % of all lesions.

It has histological  as well as  hemodynamic  significance.

How to measure eccentricity index ?

Ratio between maximum plaque thickness and minimum plaque thickness (Including the media )

Image courtesy modified from Circulation. 1996;93:924-931

In the above figure : The eccentricity index is measured  as the ratio of the maximum  to minimum plaque plus media thicknesses. In the eccentric lesion  the maximum wall thickness measures 2.6 mm, minimum wall thickness measures 0.2 mm, and eccentricity index is calculated to be 5.2.  In the  concentric lesion  the maximum wall thickness measures 2.2 mm, minimum wall thickness measures 1.6 mm, and eccentricity index is calculated to be 1.4.

What are the associations of eccentric plaque ?

Calcification and hard plaques are more common in eccentrically placed plaques.The  most vulnerable point for plaque  rupture or disruption is  the shoulder region between normal and plaque segment.

A long eccentric lesion with over hanging plaque

 

Clinical implications

  • Acute recoil
  • Coronary spasm
  • Mechanical effects : Asymmetric expansion of stent
  • Drug eluting stents

An arc of normal plaque circumference predispose to acute recoil and spasm.this is logical as the normal  arc will have a fully functional  medial smooth muscle  which are prone for spasm.

Does stenting reverse  the eccentricity of plaque ?

It may not .  The drag effect of major plaque mass may either result in plaque prolapse or  asymmetric stent approximation  or even stent crushing effect.

How does the  the stents  elute in an eccentric lesion ?

Stents are not intelligent enough to  differentiate  the plaque surface and normal surface. We  also know these drugs are  toxic to  normal endothelium  and hence  are not welcome in the normal arcs of an eccentric lesion.

Since the drug secretion   is uniform throughout the circumference   it makes the   DES a perfect misfit in eccentric lesions  As  we  realise most of the lesions are pathologically eccentric one can guess the long term  consequences .

Final message

The more we think we know . . . the less  is understood .

The images we see daily in cath labs are too simplistic to make vital decisions .There are  constant innovations coming up but none seems succeed in  imparting  common sense to  majority  us.(Namely  direct plaque intervention can never succeed over a diffuse medical  disease called atherosclerosis  )

A good reference article

http://circ.ahajournals.org/cgi/content/full/93/5/924

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  • It is a complex PCI procedure meant for  high risk  bifurcation /Trifurcation lesions
  • Two stents are simultaneously  deployed.
  • It aims to prevent sudden acute occlusion of one of the major  branches .
  • It is not an easy procedure , and be used only in rare circumstances .
  • Distal left main and ostio proximal LAD/LCX  is a  classical  example.
  • Navigation can be difficult , only well experienced operators should attempt it.

*Is there a ready made two lumen stent available ?

The image is meant for concept purpose only !

 

It is one of the techniques available to stent unprotected left main

An excellent review  in  ACC intervention journal for unprotected left main .

Click on the Image to reach the article

 


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