Feeds:
Posts
Comments

A young man aged around 40 years, had a STEMI was promptly thrombolysed in a small hospital located about 40 KM away in the suburbs of my city Chennai. They did an awesome job of saving the patient life and salvaging the myocardium.

Now begins the story . . . one of the non-medical person who is the owner of the hospital has an unfortunate working  business relationship with a frighteningly big nearby hospital  which had signed a memorandum of irresponsible understanding . It demanded any  patient who arrives in the small hospital with MI should be transferred at earliest opportunity to them.

So, an ambulance was arranged  and the patient (with a fairly well reperfused heart ) was shifted  in an emergency fashion . It reached desired destination after nicely chugging along the choked chaotic Chennai evening traffic for 45 minutes.

The guy was taken directly to cath lab through the side doors to perform a second salvage  procedure on a successfully opened IRA. Young cardiology consultants  in designer cath suite welcomed the smiling ACS patient to their posh new lab .Did few rapid radial shots, mumbled among themselves for few minutes,  decided to stent  a minimal LAD lesion for a patient who was in  zero distress with well-preserved LV function.

*The relatives of the patients were curious when they were asked sign a fresh set of consent which elaborately  mentioned about possible life risk during the procedure.

The patient’s wife  was clearly  amused and she pointed out to the superior cardiologists about  the earlier briefing by the Inferior freelance cardiologist who treated him in the previous hospital. She recalled , “I was told in confident terms  that  Initial thrombolysis  has been spectacularly  successful and bulk of the treatment is over and risk of complication has dramatically reduced”.

Then why is this distressing risk taking story again ,  she asked ?

The doctors hurriedly explained ,”this procedure is different. We are sorry to say we have no other option but to add  further risk to you” ! but , its all for your good !

Why should I ?  If the initial lysis is very successful  why do you want to meddle with it again ?

No Madam , you are ill-informed , you can’t talk like that .This is what modern  science  is all about. Leave the professional decision to us. We need to check immediately  whether the lysis is really successful .We can’t rely on the ECG.Further, true success lies in stenting the lesion as we fear the ill-fated site may close again.We are  taught to practice protocols based on standard scientific guidelines. This hospital has highest rating in-terms of quality care. That’s why we got updated ISO 2000  NABH accreditation

The women who is a soft ware engineer was smartly and  scientifically silenced in 5 minutes flat !

Post-amble :

What happened  to the patient then ? (When you fear something it happens is in’t the  Murphy’s law ?)

The apparently asymptotic and comfortable patient had uneventful PCI. A  long drug eluting  stent  was  implanted in recanalized  lesion in LAD with around 30 % narrowing that ended with an innocuous looking diagonal pinch. The procedure was uneventful , however next day he developed some fresh ECG changes and chest pain . The worried team took him for another angio found  stent was patent But , ultimately after a stressful 3 days of stay , some thing went wrong he ended up with new LV dysfunction.He got discharged fine with a caution  that , his stent needs to intensively monitored for the next 1 year since technically he had recurrent ACS !

Lessons we don’t learn from such cases.

When two procedures are done to accomplish the same aim (Reperfusion) , but with  differing success rates, expertise, time ,and unpredictable hazards , the benefits from them may not add together. There is clear knowledge deficit here. Scientific data can never provide fair answers to  these questions  as all real life cofounders can never be recreated in study population.

While we expect 1+1 to become  two in pharmaco-Invasvie strategy  ,one should realise it may end up with  either zero or even  – 2 .

1 -1 = 0

-1 + (-1)=  -2 ?

Learning cardiology from lay persons 

The patient’s shrewd wife threw this question ,

After two modes of re-perfusion done sequentially in my  husband’s  heart ,  at a total cost of Rs4.5Lakhs Why he  is  still left with significant LV dysfunction (Which was  around 40% EF.)

The query raised by the lady appeared much more crucial and logical than the ones discussed in many top-notch live interventional workshops we attend every few months!

As usual , I started mulling over the issue. There is something wrong with the way , we  understand  the pharmaco invasive approach-PIA .You go with it only if  initial pharmacological  approach has failed.

Of Course ,there is one more modality possible ie Pharmaco -Angio strategy where in, you look at the coronary anatomy and take a call ! This sounds good , the only issue is taking a right call ! My experience suggests wrong calls are the rule and  exceptions are rare. Then a whole new issue erupts about all those non IRA lesions

Final message

So,  til we have gain complete self-control over our evolved ignorance and evolving knowledge , it is better to follow this proposed  funny new ACS algorithm called “Pharmaco -non invasive” approach (PNIA)  in asymptomatic ACS patients  who have had apparently successful lysis.

*Please note, Incidentally  PNIA actually  refers to simple good old traditional stand alone thrombolysis.

Counter point

No one can deny Interventional cardiology carries a risk of untoward effects.Don’t blow this out of proportion. Do you know, how many lives have been saved by routine Pharmaco -Invasive approach ?

I am not sure , my experience may be limited.Let me ask the readers. Is routine PIA is warranted in all asymptomatic , successfully lysed STEMIs ?

100% occlusion of a coronary artery result in STEMI.This includes both thrombus and mechanical component .We are very much blinded till we touch , feel and see the lesion with a wire or IVUS to quantify the mechanical component’s  contribution in the genesis of  STEMI.It is generally believed (True as well ) thrombus is the chief culprit .It can even be 100 % thrombotic STEMI with  just a residual endothelial  erosion and hence
zero mechanical component .However , the point of contention that non flow limiting lesion is more likely to cause a thrombotic STEMI than a flow liming
lesion  seems to be biased and misunderstood scientific fact .

What happens once 100 % occlusion take place ?

Sudden occlusion , is expected to evoke a strong fire fighting response within the coronary artery.The immediate reaction is the activation of  tissue plasminogen system. In this aftermath  few succumb . ( Re-perfusion arrhythmia  generated as VF ) .The TPA system activates and tries to lyse the clot.The volume , morphology, attachment, content of thrombus ,  and the elasticity of fibrin mesh , location of  platelet core would determine the life and dissolvablity of thrombus. Even a trickle flow can keep the distal vessel patent .(Please note a timely TIMI 2 flow can be a greater achievement than a delayed TIMI 3  flow !)

thrombus propgation
What happens to the natural history of thrombus in STEMI ?
Thrombus formed over the culprit lesion can follow any of the following course

  •  Can remain static
  •  Get lysed by natural or pharmacological means
  •  Progress distally (By fragmentation or by moving en-mass )
  •  Grow proximal and and involve more serious proximal side branch obstruction
  • Organise and become a CTO

Factors determining thrombus migration

The interaction between the hemodynamic  forces that push a thrombus distally and hemo-rheological factors that promote fresh proximal thrombus formation are poorly understood. The altered intra-coronary milieu with a fissured plaque covered by  platelet vs RBC / fibrin core,  totally of obstruction,  reperfusing forces , re-exposure of raw areas and  the distal vessel integrity all matters.

While, logic would tell us,  thrombus more often migrates  distally  assisted by the direction of blood flow, an  opposite concept also seeks attention , ie since the blood flow is sluggish  in the proximal (to obstruction site )more thrombus forms in segments proximal to obstruction.

(In fact, its presumed  in any acute massive proximal LAD STEMI , it takes hardly few minutes for the thrombus to  queue up proximaly and  clog the bifurcation and spill over to LCX or even reach left main and result in instant mechanical death.)

What is the significance of length and longitudinal resistance of the thrombotic segment in STEMI ?

If thrombus is the culprit let us get rid of it , this concept looks nice on paper , but still  we don’t  know why thrombus aspiration in STEMI is not consistently useful. We also know little about  the length of the thrombotic  segment .When a guide wire is passed over a STEMI ATO it may cross smoothly like  “cutting a slice of  butter” in some , while in few we struggle and  end up with severe no-reflow inspite of great efforts .Why ?

What is the Impact of distal collateral flow in flushing fresh thrombus ?

The efficacy of collateral flow in salvaging myocardium is underestimated. Distal vessel flow if perfused partially by acute collaterals the thrombus load is not only less it’s soft and fail to get organised early that would help cross the lesion easily.

Mohandas Karam Chand Gandhi ,  father of my country , India , made these observations in year 1925  about the  fundamental constituents of  violence in society . These words of monumental wisdom came when he was  addressing young Indians in a country- side rally .

mahatma gandhi quotes medical science humanity

Note, his finger points to , what  exactly is relevant to our profession ! He emphasized this  nearly  100 years ago, when medical science was at its infancy .One can only guess what would be Mahatma’s comment about our profession in it’s  current form !

Should we include moral, behavioral and ethical classes  right from the first year of medical  school along with Anatomy , physiology and bio chemistry.Medical council of India obviously need to burn more mid night oil , I wish it happens in my life time. !

Here is a  video recipe  !

Please click here to  see more videos from my you tube site

Prosthetic valve implantation has revolutionized the management of  valvular heart disease . The original concept valve  was a ball in a cage valve  , still considered as a  fascinating discovery.  It was conceived by the young Dr Starr and made by Engineer Edwards  .This was followed   by long hours of arguments,  debates and  experiments that ran into many months . The  silent corridors of  Oregon hospital Portland USA remain the only witness  to their hard work and motivation.  At last,  it happened , the first human valve was implanted in the year 1960. Since then . . . for nearly  50 years these valves  have done a seminal  job for the mankind.

With the advent of  disc valve and bi-leaflet valve in the  later decades of 20th century , we had to say a reluctant good-bye to this valve.

There is a  lingering question among many of the current generation cardiologists and surgeons why this valve became extinct ?

Starr and Edwards with their child !

We in India , are witnessing these old warrior inside the heart functioning for more than 30 years.From my institute of Madras medical college  which probably has inserted more Starr Edwards valve than any other  during the 1970s and 80s by Prof . Sadasivan , Solomon victor , and Vasudevan and others .

It is still a mystery why this valve lost its popularity and ultimately died a premature death.The modern hemodynamic  men  working from a theoretical labs thought  this valve was  hemodynamically  inferior. These Inferior valves worked  like a  power horse  inside the hearts  the poor Indian laborers  for over 30 years.

A Starr Edwards valve rocking inside the heart in mitral position

The cage which gives  a radial support* mimic  sub valvular apparatus, which none of the other valves can provide.

* Mitral  apparatus has 5 major  components. Annulus, leaflets, chordae, pap muscle, LV free wall.None of the artificial valves has all these components.  Though , we would love to have all of them technically it is simply not possible.  The metal cage of Starr Edwards  valve partially satisfies this  , as  it acts as a virtual sub valvular apparatus.Even though the cage has no contact with LV free wall, the mechano hydrolic  transduction of  LV forces to the annulus  is possible .

Further , the good hemodyanmics of this valve indicate , the cage ensures co axial blood  flow  across the mitral inflow throughout diastole. .Unlike the bi-leaflet valve ,  where the direction of  blood flow is determined by the quantum of leaflet excursion  in every beat . In bileaflet valves  each leaflet has independent determinants of valve  motion . In Starr Edwards valve the ball is the leaflet . In contrast to bi-leaflet valve , the contact area  of the  ball and the blood in Starr Edwards  is a smooth affair  and  ball makes sure  the LV forces are equally transmitted to it’s surface .

The superiority of bi-leaflet valves and disc valves  (Over ball and cage ) were  never proven convincingly in a randomized fashion . The other factor which pulled down this valve’s popularity was the supposedly high profile nature of this valve. LVOT tend to get narrowed in few undersized hearts.  This  can not be an  excuse , as no consistent  efforts were made to miniaturize this valve which is  distinctly possible.

Sudden deaths from  Starr Edwards valve  .

  • Almost unheard in our population.
  • The major reason  for the long durability of this valve is due to the  lack of  any metallic moving points .
  • Absence of hinge  in this  valve  confers  a huge mechanical  advantage with  no stress points.
  • A globe / or a ball  has  the universal hemodynamic advantage. This shape makes it difficult for thrombotic focus to stick and grow.

Final message

Science is considered as sacred as our religion Patients believe in us. We believe in science. A  good  durable valve  was  dumped from this world  for no good reason. If commerce is the  the main issue ( as many still believe it to be ! )  history will never  forgive those people who were  behind the murder of this innocent device.

Cardiologists and Cardio thoracic surgeons are equally culpable  for the pre- mature exit of this valve from human domain.  Why didn’t they protest ?  We  can get some solace  ,  if  only we can impress upon  the current valve manufacturers  to  give a fresh lease of life to this valve .

http://www.heartlungcirc.org/article/S1443-9506%2810%2900076-4/abstract

It is often said life is a cycle , time machine rolls without rest and reach  the same  point  again and again . This is  applicable for the  knowledge cycle as well .

We  live a life ,  which is infact a  “fraction of a time”(<100years) when we consider the evolution of life in our planet for over 4 million years.

Man has survived and succumbed to various natural and  self inflicted diseases &  disasters. Currently,  in this  brief phase of life  , CAD is the major epidemic , that confronts  modern  man.It determines the ultimate  life expectancy . The fact that ,  CAD is a new age  disease   and  it was  not  this rampant ,   in our ancestors  is well known .The disease has evolved with man’s pursuit for knowledge and wealth.

A simple example of how the management of CAD over 50 years will  help assess the importance of  “Time in medical therapeutics”

  • 1960s: Life style modification and Medical therapy  is  the standard of care in all stable chronic  CAD The fact is medical and lifestyle management remained the only choice in this period as   other options were not available. (Absence of choice was  a blessing as we subsequently realised  ! read further )
  • The medical  world started looking for options to manage CAD.
  • 1970s : CABG was  a major innovation for limiting angina .
  • 1980s: Plain balloon angioplasty a revolution in the management of CAD.
  • 1990s: Stent scaffolding of    the coronaries  was  a great add on .Stent  was too  dangerous  for routine use  was to be used only in bail out situations
  • Mid 1990s : Stents  reduced restenosis. Stents are  the greatest revolution for CAD management.Avoiding stent in a PCI  is unethical , stents  should be liberally used. Every PCI should be followed by stent.
  • Stents have potential complication so a good luminal dilatation with stent like result (SLR)  was  preferred so that we can avoid stent related complications.
  • 2000s: Simple  bare metal stents are not enough .It also has significant restenosis.
  • 2002: BMS are too notorius for restenosis and may be dangerous to use
  • 2004 : Drug eluting stents are god’s gift to mankind.It eliminates restenosis by 100% .
  • 2006:  Drug eluting stents not only eliminates restenosis it eliminates many patients suddenly by subacute stent thrombosis
  • 2007 : The drug is not  the culprit in DES it is the non bio erodable polymer that causes stent thrombosis. Polymer free DES  or   biodegradable stent , for temporary scaffolding  of the coronary artery  (Poly lactic acid )  are likely to  be the standard of care .
  • All stents  are  potentially dangerous for the simple reason any metal within the coronary artery  has a potential for acute occlusion.In chronic CAD it is not at all necessary to open the occluded coronary arteries , unless  CAD is severely symptomatic in spite of best  medical therapy.
  • 2007: Medical management is superior to PCI  in most of the situations in chronic CAD  .(COURAGE study ) .Avoid PCI whenever possible.
  • 2009 :The fundamental principle of CAD management  remain unaltered. Life style modification,  regular  exercise ,  risk factor reduction, optimal doses of anti anginal drug, statins and aspirin  is the time tested recipe for effective management of CAD .

So the CAD  therapeutic  journey  found  it’s  true  destination  ,  where it started in 1960s.

Final message

Every new option of therapy must be tested  against every past option .There are other reverse cycles  in cardiology  that includes the  role of diuretics  in SHT , beta blockers in CHF etc. It is ironical , we are in the era  of rediscovering common sense with sophisticated research methodology .What our ancestors know centuries ago , is perceived to be great scientific breakthroughs . It takes  a  pan continental , triple  blinded  randomised trial   to prove physical activity is good  for the heart .(INTERHEART , MONICA  studies etc) .

Medical profession is bound to experience hard times in the decades to come ,  unless we  look back in time and “constantly scrutinize”  the so called  scientific breakthroughs and  look  for genuine treasures for a great future !

Common sense protects more humans than modern science and  it comes free of cost  too . . .

NSTEMI  constitutes a  very heterogeneous population .The cardiac   risk   can vary  between very low to very high .  In contrast ,  STEMI patients  carry  a high risk for  electro mechanical complication including   sudden death .They all need immediate treatment  either with  thrombolysis or PCI to open up the blood vessel  and salvage the myocardium.

The above concept , may  be true in   many situations  ,  but what we fail to recognize   is  that ,   STEMI   also  is  a heterogeneous clinico pathological  with varying risks and outcome !

Let us see briefly ,  why this  is very important  in the management of STEMI

Management of STEMI  has undergone great  change  over the past 50 years and  it is the standing example of evidence based coronary care in the modern era ! The mortality  ,  in the early era was around 30-40% . The advent of coronary care units, defibrillators, reduced the mortality to around 10-15%  in 1960 /70s . Early use of heparin , aspirin   further improved the outcome .The inhospital mortality  was greatly  reduced to a level of  7-8% in the thrombolytic  era. And ,  then  came the interventional approach, namely primary PCI ,  which is now considered the best form of reperfusion when done early by an experienced team.

Inspite of this wealth of evidence   for the   superiority  of PCI  , it is only a fraction of  STEMI patients get  primary PCI   even in some  of the  well equipped centers ( Could be as low as  15 %)

Why ? this paradox

Primary PCI   has   struggled  to establish itself  as a global  therapeutic concept  for STEMI ,   even after   20 years of it’s introduction (PAMI trial)  .  If we  attribute ,  lack of   infrastructure  , expertise are  responsible for this low utility of primary PCI , we are mistaken ! There are so many institutions , at least in developing world ,   reluctant to do primary PCI  for varied reasons.( Affordability , support system , odd hours ,and finally perceived fear of untoward complication !)

Primary PCI may be a great treatment modality , but it comes with a inherent risk related to the procedure.

In fact the early hazard could exceed the potential benefit in many of the low risk STEMI  patients !

All STEMI’s are not  same , so all does not require same treatment !

Common sense and logic would   tell us any medical condition should be risk stratified before applying the management protocol. This will enable  us to avoid applying “high risk  – high benefit”  treatments in low risk patients . It is a great surprise,  the cardiology community has extensively researched to risk stratify NSTEMI/UA   ,  it has  rarely  considered risk stratification of STEMI before  starting the treatment.

In this context , it should  be emphasized  most of the clinical trails on   primary PCI  do not address  the clinical  relevance and the  differential outcomes   in various  subsets of  STEMI .

Consider the following two cases.

Two young men with STEMI  , both present within  3  hours   after  onset of symptoms

  1. ST elevation in V1 -V6 , 1 , AVL   ,  Low blood pressure , with severe  chest pain.
  2. ST elevation in 2 ,3, AVF , hemodynamically stable , with minimal  or no  discomfort .

In the above example,   a  small inferior  MI by a distal RCA occlusion  ,  and a proximal LAD lesion jeopardising entire anterior wall , both  are  categorized as STEMI !

Do you want to advocate same treatment  for both ?  or Will you  risk stratify the STEMI and treat individually ?  (As we do in NSTEMI !)

Current guidelines , would  suggest PCI for both situations. But , logistic ,  and real world experience would clearly favor thrombolysis for the second patient .

Does that mean,  the second patient is getting an inferior modality of treatment ?

Not at all . In fact there is a strong case for PCI being inferior in these patients as the risk of the procedure may far outweigh the benefit especially if it is done on a  random basis  by  not so well experienced cath lab team.

(Note : Streptokinase  or TPA does not  vary it’s action ,  whether given by  an ambulance drive or a staff nurse or even a  cardiologist !  .In contrast ,  the infrastructure and expertise have the  greatest impact on the success and failure  of PCI )

Final message

So , it is argued the world cardiology societies(ACC/ESC etc)  need to risk stratify STEMI (Like we do in NSTEMI ) into low risk, intermediate risk and high risk categories and advice primary PCI only for high risk patients.

Significant MR is a contraindication for PTMC. However,  If MR jet is central , and mild (some times little more than mild as well ) PTMC can be safely done. The MR may not worsen .It may even disappear.

Note: Eccentric MR jets are indirect evidence for sub valvular disease. Its very likely to get worsened and may require a mitral valve replacement .

Here is patient with severe mitral stenosis, the MR is in all probability safe.

Angle of eccentricity 

One must realise , the eccentricity of a jet is not very objective .What may appear as central jet in long axis may be wall hugging in 4 chamber view. This is very important to recognise. Further , even central jets can reveal a invisible eccentricity detected only on 3D MR jet reconstruction.

One simple way to ascertain central jet is to  check whether the MR jet align in the same angle as diastolic color jets of MS into LV inflow . (Looking carefully ,the diastolic color jets also provide us info about sub-valvular disease )

More anatomical distortion in this patient 

Incidentally , this patient also had another anatomical adversary  ie ,the bulge of IAS into right atrium. This can happen two ways .Septal aneurysm or a normal septum bulging to RA due to raised mean LA pressure.

 

img_20190214_184238254084131.jpg

Miral stenosis with Atrial fibrillation showing the changing mitral inflow jet .

 

img_20190205_163719776750314.jpg

The radius of curvature of IAS bulge Indicates its more of septal weakness that contributes than the raised pressure. There is a small risk in these patients the IAS flap may give way during the procedure and a small ASD may be created .(Hemodynamically may not be significant though)

 

How does the MR disappear after balloon dilatation ?

If you ask this question , it means your are a thinking cardiology fellow , good.

Guess your answer. Its all about physics of  MVOs behavior  in systole and diastole . The mitral valve tissue attachment and adhesion causes not only a  diastolic narrowing but also a fixed systolic regurgitant orifice.Once you relive it the leaflets begins to co-opt normally without a systolic leaky orifice.

Final message

Though there are clear contraindications ,suitability of mitral valve for PTMC is more of a personal experience and confidence. A MR jet of grade 1  may be acceptable. A huge LA, Distorted IAS anatomy, a clot confined to LA appendage are relative contraindication only. The puncture site on IAS , minimal manipulation guide wire within LA, a gentle over the wire technique to cross mitral valve or some of the tips for success.

Never hesitate however to refer complex cases of mitral stenosis to the surgeons. Of course , you can’t insist them to do a valve preserving OMV .It is unfortunate(They have good point of argument as well)  most of the surgeons have have made Mitral valve replacement as a default modality

Post ample :

When we were cardiology fellows , we used to have a mitral valve scoring system for suitability for PTMC. Its called Wilkin’s score. Its a purely an anatomical score. (I guess still its expected in Board exams) What we need is comprehensive anatomical and physiological assessment of mitral valve. With due respects to  published literature this scoring system lacks  two  vital parameters we look before PTMC , namely the extent of commissural calcium  and degree of MR.

 

Cardiologists are grappling with at least  half a dozen time windows  in the management of STEMI. (It can be combinations of any of the following :Symptom – DAPT Loading – Door – Needle /Balloon-Sheath, wire crossing etc ) Time windows are Important in choosing the right (or no)modality of re-perfusion . Though superiority of  primary PCI  is thought to be established in academic community , it  may not be in real world. Published studies that suggest pPCI is superior to lysis at any time window  still lack good evidence.

Why is this long drawn confusion  ? 

One of the important determinant of outcome in STEMI , is the thrombus organisation (hardening )time . Some how we have assumed PCI can tackle hardened thrombus  much better than lysis (In fact the outcome in late PCI is as bad or good as lysis in terms of true myocardial reperfusion in this population.This fact will not be visible in scientific data that’s read superficially .One has  to  mine deep for the truth) (Claeys MJ,. . Arch Intern Med. 2011;171(6):544–549)

Two more virtual pathological Time windows.

While we are preoccupied with certain time windows in STEMI  ,may I suggest  two more  Invisible pathological windows. I don’t know , whether these are presumptive theoretical stuff ,  but understanding these time windows will sharpen our decision-making skills in STEMI.

1.Symptom to  ATO time (Acute total occlusion) 

ery gets occluded(ATO ).This is truly Invisible time window .( Pre-Infarction angina  to Infarct time ) Taking the last episode of most Intense pain need not refer to beginning of ATO / Infarct pain. (ACS being as dynamic process in a 24 hour time span an angina  can even be post Infarct angina!)

2. ATO to thrombus organising (hardening) time

It is obvious time is primary factor that correlates with thrombus organisation. But there is much more to it. It’s not the fibrin organisation alone that makes a thrombus hard. ATO gets reinforced by plaque and tissue material ( like steel rods  inside cement) In other words no one really knows  when does the thrombotic process begin or end  and  hardens thereafter. But we know for certain is  tackling a hard thrombus is difficult for both modalities currently we have lysis and PCI*

.(Almost forgot the third modality,  yes its humble drug heparin(.It can do wonders little slow though , Slowness doesn’t matter beyond 24 hrs is it not ?) Now there can be a role for Warfarin also to get rid of chronic IRA thrombus (Moon JY, N The role of oral anticoagulant therapy in patients with acute coronary syndrome. Ther Adv Hematol. 2017;8(12):353-366.)

There are excellent studies that correlated time window to thrombus hardness.At least in  50%  IRAs with time  window less than 12 hrs have thrombus age more than 24 hours Some of the thrombus material aspirated has been shown to be many days old (Kramer et al PLoS One. 2009;4(6):e5817)

Image source : Miranda C.A. Kramer Relationship of Thrombus Healing to Underlying Plaque Morphology in Sudden Coronary Death Volume 55, Issue 2, January 2010

How to arrive at the age of the thrombus  ?

It’s a difficult task to guess the age of thrombus with help  symptom onset and ECG .  There  can be 50 %  error as discussed earlier.

Is coronary angiogram helpful ?

There is no good clue to differentiate fresh from old thrombus by just looking at angio shot. Some experts are able do it (Guess it ?)

Poke and feel with guidewire  : This is probably the best way to tell whether thrombus is fresh or old (Still not fool proof ) Most of us do this in STEMI . All is well if guide wire cuts through  smoothly and nice flow is established.(What we call guide wire angioplasty) Procedure is completed with or without a stent ( &residual lesion) .This is the most gratifying and desirable outcome of primary PCI. (Note : Hardness of thrombus can be overcome stiff wires and force.That doesn’t make it a fresh clot ! This is where we may end up with No-reflow)

nrcardio.2016.38-f4

Image courtesy : Karim D. Mahmoud & Felix Zijlstra Nature Reviews Cardiology volume 13, pages 418–428 (2016) Various forms of thrombus aspirated during primary PCI.

When poke test fails  . . . be ready for a long haul or quit

Thrombus is not a single aged mass of blood. It has lawyers of clot with different maturity  ( like shells over earth ).Hence poking has its own side effects too.Some of it can be violent.When  deeper layers of old thrombus is exposed to fresh blood it can create fresh  cycle of clot activation.( Ofcourse we fight it out with DAPT and heparin) Winner of this fight can never be predicted. To conquer the thrombus or quit is directly linked to the cardiologist wisdom.

What about OCT/IVUS ?

They could help us to assess the morphology of thrombus and give  us Indirect clues about the age of thrombus. Some of the experts say they use it efficiently . My opinion is it adds more glamour than true enlightenment .(Mind you , we need to  cross , clear and flush the vessel to complete OCT. The fact that we are able to complete OCT in STEMI settimg would mean  thrombus is  fresh .In that way it may be useful but without a true purpose.)

Thrombus aspirate analysis : Its more scientific way of arriving at the age of thrombus (Any one want to do carbon dating on this ?) , This again lacks practical use as we need to assess  the thrombus age before poking to avoid subsequent complications. It is also not clear whether thrombus in STEMI is more of RBC and fibrin and net platelet content can’t be quantified.This especially true in stuttering ACS where NSTEMI is threatening to become STEMI or vice versa. (Platelets love to hug each other at high shear force , RBCs do the opposite )

Is the Consistency of the thrombus uniform ?

Here comes the importance of the length of the thrombotic segment. It’s estimated the length of the thrombus segment can be anywhere between 1 cm to entire length of the coronary artery distal to the site of occlusion .The initial proximal part may be soft as its directly exposed to DAPT and heparin.The distal thrombus is flushed only with collateral or a trickle of flow from anti-grade .So ,very likely the distal thrombus is harder than proximal.

How does DAPT loading and subsequent heparin interfere with thrombus organisation ?

Loading DAPT has a definite impact and prevents hardening.(But, one issue is it shouldn’t have been happened before administration)

What is the natural history of organised hard thrombus in IRA ?

  • It transforms  into a CTO.(Many of us believe this is dominant theme)
  • Late total recannalisation – 20% by 30 days
  • Partial recannalisation  (More than 20 % ?)
  • Since wide-spread use of predischarge PCI , true natural history is masked.

Final message

Taming STEMI with pPCI  is not always  a time sensitive emergency procedure . It’s important to recall STEMI patients can harbour thrombus with different maturity .We know STEMI can occur even in  patient with chronic thrombotic process also (even a CTO) . This is proven by a simple fact people walk in 3 days after MI casually. Further, during pPCI both early and late arrivals have equal difficulty though they carry different set of problems tackling the IRA.

If we really  believe principles of coronary care is aimed at tackling coronary thrombosis , wisdom  lies in  judicious use of both CCU and Cath lab facilities .Never hesitate to rush back the patient to CCU for a quick lysis (Or Intra coronary) and avoid the potentially prolonged  battle against huge mass of hard thrombus.

Reference 

 

Post-ample : A quote 

Importance of  early arrival of STEMI patient to nearest hospital is huge , not because of the possibility getting an emergent PCI . Rather, it is  due to fact that simply reaching the nearest coronary care center dramatically reduce the mortality.(My guess is , this mortality benefit should be more than Lysis/pPCI put together)

Let me see how many find sense in this Nonsense !


Cath labs are propably the best place to practice preventive cardiology . . .

Practice of medicine is primarily guided by Infinite Information , plenty of Intuition, little bit of Intelligence and unquantifiable amount of Ignorance.The science of coronary reperfusion is standing example for variable mix of the above.The term no reflow is a jargan used liberally in cath labs right from first year fellow to super consultant without knowing what exactly they mean by it.

What really is No-reflow then ?

The academic definition :According to Kloner no-reflow is defined as suboptimal myocardial reperfusion through a part of coronary circulation without angiographic evidence of mechanical vessel obstruction.( Kloner RA, Ganote CE, Jennings RB. “The “no-reflow” phenomenon after temporary coronary occlusion in the dog.” Journal of Clinical Investigation, 1974; 54: 1496–1508.)

With due credits to his seminal paper, I always wonder what exactly Dr Kloner meant when he labelled it as No-reflow!

No is ok , Flow is ok , What does the adjective “re” mean to you ?

Re stands for repeat ? recurrent ? Yes , it may mean any one of it. It may mean nothing in many patients as their post PCI flow is same or found to be no better than pre PCI flow with no significant forward flow at all ! In this situation No-reflow is same as No-flow (Never flown ) in physiological terms irrespective of epicardial patency.

Literally, the term no re-flow tell us, there has been a dramatic procedure related*( or preexisting ) destabilization in distal blood flow. It can be any downgrading of basal TIMI flow. ( Example : TIMI 3 becoming Zero , or TIMI 1 becoming 3 then back to 1 or Zero.) The terms slow flow, low flow, stuttering or trickle of flow all fall under the common  category No reflow. In a crude manner one may conclude no reflow to be  masquereding term  for failed PCI.

*Mind you , No reflow can also occur with pharmacological lysis as well.(Less common)But personal experincee suggest it has a less benign course.

Mechanism of No- reflow

Many mechanisms has been proposed and disposed by experts. However , all suggested mechanisms end up in the final common theme ie micro vascular obstruction.

Can no-reflow precipitate a fresh ACS ?

Could be yes . How ? The distal thrombus migration clogs the active collateral channels at its entry point.This is probably the most unrecognised concept which is difficult to prove though.The problem is , we may not realise this as it could be silent or may just present as LV dysfunction , Infarct extension, or Ischemic cardiac failure.

Why is treatment of no reflow is so dismal ?

I think, by now you can guess the answer and get it right too !

Is no flow better than No-reflow?

It may seem a foolish question one could come across in coronary hemodynamics. The prevailing coronary doctrine, as we understand is , all ATOs need to be opened in STEMI in an emergent fashion. (Other wise patients or their myocardium can’t be salvaged )But, we also realise ATO do get converted to CTOs in a safe manner following a STEMI in a significant number. It’s the ultimate myocardial mystery when we realise even the ATO fails to damage the myocardium significantly in some patients.

Presence of acute collateralisation to IRA from non IRA is observed instantaneously and spreads rapidly towards myocardium in distress.It is observed in atleast 40% of all patients.(Ref 2,3).

The anatomical and physiological codecs of acute collaterals in ACS is secretly located close in the God’s domain.But, Interfering with it, is definitely in human domain.

Should we need to worry about the impact of PCI on these acute collaterals ?

It is estimated up to 5 grams of thrombus could spilled over to the distal coronary bed. Mind you thrombus formation is not a one time process.Can you guess where these thrombus lodge in ? We don’t know what is thrombus clearing capacity of LAD/LCX/RCA vascular bed. But. we have observed naturally formed thrombus is less likely to disseminate and migrate than the catheter and wire induced.My presumption is , coronaries show their dissent and disapproval in the only way they know, ie non stop generation of thrombus (Not withstanding our DAPT/2b 3a /Bivaluridins etc)

Acute collateral shutdown : A new concept

We are not sure if there is a collision between two streams of reperfusion that happens after a STEMI. One spontaneous from the collateral and other from antegrade(Either spontaneous or man made)

Is it benefitial, detrimental or neutral ? We don’t know the answer for sure. My understanding is some of subset of critical STEMI are heavily dependent on this life line however miniscule it may be.

It doesn’t require a double blinded study to prove what would happen when a hurried cardiologist attempt hurried PCI who often has to a change his target to thrombus instead of myocardium .

When aggression is shown on the thrombus, it’s more likely you end up in no reflow . One possible new mechanism(Proposed by the author) of No reflow is distal dissemination of thrombus debri that plugs the lateral entry points of collaterals.

This is the time , no reflow shows its violent face. Invariably hemodynamic deteriation occurs and the entire reperfusion team would seem to count their luck than expertise.

Can we perceive, predict and prevent this ?

We should , we need to , but how ? Since we know the true success rate of no reflow is miniscule, serious introspection to be done. Funnily (but realistically) one can take a famous cue from the most underrated medical specialty Social and preventive medicine .

Yes it’s “Prevention is better than cure” and mind you, if there is no cure, how important prevention becomes.Strangley , preventive cardiology is meant for lesser professionals , who and talk about diet, excercise and lifestyle.

No , it’s not . Preventive medicine needs a new defintion , rather new understanding .Its’ all about preventing an expected or unexpected adverse event anywhere.

How many of us really believe there is no effective cure for No-reflow and it is directly related to aggressive thrombus clearance strategies .

Should we argue new age Interventionists to practice preventive cardiology right inside the cath lab and do away with non-academic temptations.(Surprise , this is exactly mega trials on thrombus aspiration told us (Class 3 Indication for routine thrombus meddling)

Final message

Stable and comfortable, late ATOs need not be opened like defusing a time bomb. We will never know which side of the bomb the cardiologist is sitting.

The incidence of new onset No-reflow can be higher than what we presume.Further it can trigger a fresh ACS by whipping up the injured and resting myocardium.(Mostly attributed to late reperfusion Injury and the acute collateral shutdown.)

Postample and Counterpoint

As an interventional cardiologist, No-reflow is one among the expected complications , which are part of the profession.Never bother about these unscientific utterrings . That’s the job of critics. You go ahead and fight with the coronary artety in every case of ACS. Only weak minded unprofessionals would love to sit on a case of ACS and play a waiting game in CCU. True professionals shall look for multiple criminal targets beyond thrombus, myocardium, IRA , non IRA, doesn’t matter . Do it with confidence.Hope for the best, don’t bother too much about the endpoint.

Mind you, that’s what , we are trained and paid for and possibly respected too in this most glamorous subspecialty of Medicine.

Coming next

*Is Catheter, Guidewire Induced thrombus radically different from natural denovo thrombus ?

*How common is angiographically blind No reflow.(TIMI 3 with good and bad blush included)

*What are the residual defects and long term myocardial sequale ? (Inspite of successful tackling of No reflow )

Reference

1.Claire Bouleti et all The no-reflow phenomenon: State of the art Le no-reflow : état de l’artArchives of Cardiovascular Disease (2015) 108, 661—674
2.L YJ,Masuyama T,Mishima M, et al Effect of pre-reperfusion residual flow on recovery from myocardial stunning: a myocardial contrast echocardiography study. J Am Soc Echocardiogr 2000;13:1825. doi:10.1016/S0894-7317(00)90038-5

3.Ha M, Sakata Y, Nakatani D on behalf of the OACIS Investigators, Sakata Y, Nakatani D on behalf of the OACIS Investigators, et al

Impact of coronary collaterals on in-hospital and 5-year mortality after ST-elevation myocardial infarction in the contemporary percutaneous coronary intervention era: a prospective observational study

Human body is intertwined collection of lives of Individual organs.We believe death occurs when brain dies , respiration stops and circulation ceases . Curiously ,when life ends , these organs  don’t die as a single unit . These three events can happen in any of the six possible permutations.Each organ takes different times to die after loss of life.It is like a crashed computer , where the mother board /RAM memory may be transferred to another and be functional . Out of these three , heart function appears to be supreme as it can function without the need of brain (Science of brain-death) and keep the body alive with intact circulation. Though the concept  called heart dead organ donors is catching up as well. (John Gill et all Use and Outcomes of Kidneys from Donation after Circulatory Death Donors in the United States    

The science of organ transplant has rapidly  evolved .We can transfer an organ from one who is dying or dead to another person who is also dying due to failure of a different organ. Though most organs can be transported and transplanted , we need to maintain life in a dead donor organ . A new and curious specialty  in medicine is emerging which could be named a  Critical Care of Dead or Critical Cadaveric Care Units !) till harvesting happens. Paradoxically ,after the harvest , the organ gains independent  life that has to be sustained.This is where the science of organ transport is waiting in to explode!

How to transport a dead man’s heart ?

There are two Ischemic times in organ donation.

  • Warm Ischemic time
  • Cold Ischemic time

Warm ischemic time refers to the amount of time that an organ remains at body temperature after its blood supply has been stopped or reduced. Cold ischemic time refers to the amount of time that an organ is chilled or cold and not receiving a blood supply. These times quiet vary with respect to different organs.

So far, we have been carrying organs in cold boxes with custodial solutions. (HTK*)

runtranslplant265x125_1234539

This makes the transport time a big limitation of success of the procedure. *HTK -histidine, tryptophan ,a-ketoglutarate, solution 

Whats new in organ transplant science ?

Trans medics is an exclusive company , that has pioneered  in this unique science of organ transport .They have developed separate organ care system for heart ,lungs and liver.

donor heart

It is the first portable heart perfusion system , which increase the time between the harvest to transplant . It avoids cold ischemic time ,replaced by warm perfusion with metabolic activity monitored till  it is transplanted.Ideal far long distance transplant .Soon one can expect trans-continental transplant as well !

This technology could make the difference between warm and cold Ischemic times blurred and in future one may expect to prolong the warm ischemic  period and there is near zero cold Ischemic time.

A heart is perfused by transmedics system while being transported

 

                                              A  lung breathing in transit

A link to a video

Final message

Modern medical technology can be seen in action , in so many ways and brings both accolades and agonies in equal proportion. While, even flimsy ones tend to get due attention , Transmedics , probably deserves a  grandest reward  for uplifting the science of organ donation . I would think this is the most unique service (playing God )  . . . shipping dead man’s organ  with assured life on delivery  !

 

Link to Transmedics website

ocs heart transmedics heart transplantation

http://www.transplantation.de/fileadmin/transplantation/txmedizin/txmedizin_2011_3/04_yeter.pdf

 

A middle aged women , with acute onset left sided chest pain and ECG changes was seen by a general physician. He had little hesitation in labeling the patient as  ACS( To be precious he reported the ECG as lateral wall Ischemia) and asked for an echocardiogram to rule out a heart attack  (This is how cardiology is practiced in many areas) .

This patient came to my lab  for the Echocardiogram .The echo window was poor , It showed a structurally normal heart and there was no pericardial effusion. I suspected something systemically wrong in this patient and asked for a X ray chest .

Subsequent scrutiny of this  patient revealed she had moderate left tuberculous effusion. ECG changes are attributed to this. We know pericardial disease can cause ECG changes that mimic ACS. While pericarditis can elevate the ST segment. Can pleuritis without effusion cause ECG changes.  What is the demarcation point between pleural from pericardial surface ?

What are the ECG features of pleural effusion ?

  • Low voltage qrs.
  • Poor R wave or even q waves
  • QRS axis shifts are due to true anatomical / electrical shifts
  • T wave inversion as in this patient

Mechanism of T wave inversion in plural effusion.

T wave represents ventricular repolarisation. To be frank I am not able to give an exact mechanism of such  defects in pleural effusion.

The following mechanisms are  suggested

  1. Left sided pleural effusion can closely mimic pericardial effusion .One can get low voltage QRS in lateral chest leads .
  2. Anatomically I would guess the plural fluid also hugs the heart and the inflamed pleuro-pericardial Interface (Is there fibrous continuity ?) result in some degree of epicardial interference or reversal in electrical polarity.
  3. The true effects of mediastinal shifts with large effusions  on ECG is not clear(Lead V 3 and V4 may pick V5 / V6 signals in left sided effusions )
  4. Fluid altering the electrical conduction property
  5. Associated minimal pericardial effusion and  effectively causing epi-pericarditis as a part of poly-serositis .
  6. After ruling out all plausibility one may think primary ischemic changes as well.

Teaching points and potential error

To label  a left-sided pleuritic pain with ECG changes as ACS can never be considered as a serious error.However , rushing such patients to cath lab or   lytic therapy along with heparin leads to more trouble. ER physicians should always keep in mind T wave inversion in isolation is indeed a rare cause* of ischemia. Still,  as a physician first , we need to have a check list to rule out common non cardiac conditions. Pneumothorax is one another entity that can exactly mimic a STEMI with ST segment shifts and q waves.It’s also possible left sided pleural effusions produce q waves and mimic an old MI as this case report reveals.(Constatine A Manthous Chest 1993)

I think  X-ray chest is least used modality in a coronary care unit for various reasons . Still ,the utility of which can never be undermined and should be used diligently . 

*Of course we shouldn’t  forget a sinister form of ACS  referred to as Wellen’s LAD  syndrome which may present with dynamic T inversion.

Reference

The prime job of cardiologists is to restore coronary blood flow in an emergency fashion. While we do this with reasonable success ,there is still a missing link between our Initial aim and achieved goal.

It’s all too common situation in any busy cath lab , to see two similar STEMI patients with identical time window & proximal LAD as IRA , in totally different scenarios. In the first patient we find a trickle of flow in LAD , who is relatively comfortable  with normal LV function (In whom , emergency primary PCI might appear redundant.) While the other patient , even after rapidly established TIMI 3 flow , LV wouldn’t look good at all . All our efforts to reperfuse is found wanting.  Ultimately LV goes in a downward spiral , ends up in irreversible cardiogenic shock or fatality inspite of Impellas, ECMOs and other LV assist exotica !

 

intra-coroanry-thrombus (2)

I can promise , you can never guess from the angiogram whether this ACS patient was very much comfortable or he is in cardiogenic shock on ventilator  unless I reveal the history. Am I right ? That is the mystery of coronary circulation and hence its so critical to serve the myocardium what it wants ? Never treat a coronary artery in isolation !

What is the possible explanation ?

The first trickle (Say TIMI 1 which is usually spontaneous or lytic related ) is the one that’s going keep the muscle viable and possibly prolong the time window for the subsequent reperfusion strategies .Hence it is the timely TIMI 1 or 2 is much more critical than delayed TIMI 3 (Still rapid).

Time window woos :

Who fixed the reperfusion  time window as  6 to 12 hours ? Do you know on what basis  the acceptable delay of 30 to 60 mts related to primary PCI ? was made acceptable by  cardiology community ?  If you analyse the published data both are highly contentious and empirical. ( Suggest you scrutiny the data from DANAM2 , PRAGUE and AIR PAMI and come to your own conclusion) (*These are the 3 sacred studies done with few thousand patients  that redefined our approach  to STEMI and gave the licence to waste the golden hour ! )

I remember reading  the Robins pathology book (Bible of  pathology William Boyd as well ) in early days of medical school myocardium may die even within 1 hour with wavy necrosis, contraction bands etc. Looking back some times I  wonder how the clinicians have conveniently prolonged time window with whims and fancies of science Intact.

Concurring with the pathologists , we have learnt some harsh lessons inside the cath labs. One of them is that even ultra fast pPCI can fail to salvage  myocardium, meaning that time is not the ultimate thing in our race. (There should be other important determinants )

A brief journey back into our pathology classes : Have a look at this table 

Time window in stemi 6 hour 12 hour or 90 minutes

Please note, Irreversible Injury might happen any time after 30 minutes .Of course it can vary . But, the question is how are you going to identify these patients with  ultra short  time windows? source : Robbins Basic Pathology 9th Edition.Elsevier

Other factors that influence myocardial cell survival

Re-perfusion is not a single edged sword 

We may wish the concept of re-perfusion Injury is a myth : Unfortunately it is not ! Myocardium doesn’t relish (not always) the return of circulation in full dose. (May be it’s laying and taking the much needed rest with the initial Injury!)

Reperfused myocardium

Sudden gushes of blood leads to extravasation into the interstitium (due to damaged capillaries)  increases the Intra myocardial resistance and obstructs the microvascular flow. We have  witnessed more than a handful of patients going for cardiac arrest once IRA is opened (of course,  we might be  able to resuscitate many of  them )

Myocardial hypoxia resistance time

Please realise ,true  STEMI clock starts not with onset of symptoms but with time of total occlusion.There is more than subtle difference between the twoOnset of total occlusion to symptom time is not a well explored or understood Interval. We take it for granted that the onset of symptoms coincides with total occlusion.

But in multi vessel CAD, even a CTO can cause a STEMI through loss of distal collaterals. Further ,the presence and absence of pre-infarction angina (PIA*) , ischemic pre-conditioning (IPC*) sensitizing effect of  remote CAD , manifest vs recruitable  collaterals  all these make the fixed time windows with which we did our land mark studies of PCI / lysis academically  questionable.

* Both PIA  IPC are master confounders in the true time window calculations .We don’t know whether its due to ischemia tolerating myocytes or pain tolerating nerve fibres  responsible for this varying presentations.But the mystery is certain , when we  realise the angiographic  spectrum of ACS can range from silent ATOs to painful CTOs

Final message

Is timely reperfusion (and its favorable effect ) lies in God’s domain ? If you we  believe myocardial susceptibility , arrhymogenicity and recovery to hypoxia is genetically determined ,then the difference between fate and science Is much narrower than we think .Its appears we can change the former with the later with both positive and negative outcomes. So ,the  “f”  word may not be a forbidden at-least in the STEMI management. It resides not only  within the human genomic codecs written with double-helical nucleic acid fonts . . . but also  in the nimble and restless hands of both novice and experienced interventionists !

                       

A study proposal 

Let me make a hypothetical statement .A significant subset of patients with STEMI have ultra short myocardial survival and we are unable to identify these hypoxia challenged hearts where primary PCI related delay could be a myocardial sin. Any one willing to prove or disprove this hypothesis ? If some body take this quixotically important study in STEMI management please give me some credit as a contributor !