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The age old  statistics , 30 % of deaths following STEMI happen even before patients reach the hospital may still be true. But ,there is an untold story that happen regularly in the rehabilitation phase .Its ironical many  apparently stabilised STEMI patients still lose their life just before they get discharged or within 30 days .More often than not this happens in the toilet when they strain for defecation. At least a dozen deaths I have witnessed in the last few years. Of course we have resuscitated many near deaths as well.

What exactly happens to these ill-fated patients inside the toilet  ?

Straining is often an isometric exercise and prolonged strain ends up in   valsalva maneuver , a prolonged valsalva strain realistically shuts both vena cava due to raised intrathoracic  pressure .Vena caval shutdown is equivalent to asystole and imagine the chaos in the  delicately recannalised LAD when the coronary perfusion pressure nose dives (Even the  stented segment in IRA is vulnerable as distal flow restoration may take time   !)

The sudden systemic hypotension leads to  fall in coronary arterial pressure proximal  to the lesion. The normal physiological response to proximal fall would be corresponding distal fall maintaining the flow gradient . If the microvascular bed is damaged( loss of capacity to vasodilate ) this distal fall may not happen promptly .So its acute standstill of flow  across IRA ( or even Non IRA if it has a lesion )  triggering events that rapidly destabilise  unless intervened.

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hemodynamics of ffr lad valsalva 2

 

 

 

 

 

 

 

 

 

 

 

 

 

Other modes of sudden toilet deaths

*The opposite process , ie sudden spikes of blood pressure (In contrast to hypotension of  Valsalva strain ) can  occur as straining is equivalent to Isometric exercise which increase afterload .This can either cause LV failure, another episode of ACS, myocardial stretching, even tear it and result in mechanical complication.

  1. Acute LVF triggered by spikes of BP /new onset ischemic MR.
  2. Free wall rupture and tamponade.
  3. Emboli getting dislodged from LV during strain

How to anticipate and prevent these  deaths ?

  • All complicated STEMI patients should have special rehabilitation program.
  • A simple rule could be patients with persistent ST elevation with  are prone for further events.They should be flagged. (Stented / TIMI flows matters very little !)
  • Restrict all vigorous activity for minimum of one to two weeks ( I am not a believer of pre-discharge stress test even in uncomplicated MI  )
  • Use laxatives adequately.
  • Western toilets may have an hemodynamic advantage. Indian closets that require squatting which increase the venous return , ultimately it compromises coronary hemodynamics more. We don’t understand as yet ,what will happen if one perfoms a valsalva  and  squatting simultaneously.(Which will prevail over the other ?)
  • Finally toilet shouldn’t  be locked during rehabilitation for safety purposes.
  • All post STEMI pateints should have registered with emergency contact and alert service ready.

Has primary PCI has reduced the sudden deaths  in Post MI period in current era ?

I’m afraid , I can’t say a dogmatic yes . May be ,to a certain extent , However,  it has created a new subset of perfectly  stented still prone for ACS.A physiologically or pharmacologically  recannlised IRA generally heals by themself. A Stented IRA  hands over  the responsiblity of healing the injured IRA to us  .Ofcourse ,we try to do it  with lot of difficulty  .(Different versions of  confused DAPT  regimens !)

Final message 

Please note , “discharge to 30 day mortality” following STEMI   which is  upto 2 %  .It is the most neglected  and  mismanaged phase in coronary care .Toilets are definitely not a benign place for them and all the good work done by you in cath lab and CCU can be nullified in few Innocuous looking seconds !

Postample 

Is Toilet room death amounts to  negligence / mis-management  inside hospital ?

May be there is a reason for this argument. When to ambulate in complicated STEMI is a big question. ? Though we have guidelines some of the patients are reluctant to use assisted service.

I think its a calculated risk , and  there is trade off between the benefits of early ambulation and potential exertion related risk.

One such argument by a cardiologist in a medicolegal situation goes like this. “I thought my patient’s heart  is stable enough to use toilet , it misfired , hence it is just an error of  judgment. I can’t be faulted.  Though this argument appear logical , many times it can’t hold water in court of law !”

Reference

1.Siebes M, Chamuleau SA, Meuwissen M,   Influence of hemodynamic conditions on fractional flow reserve: parametric analysis of underlying model Am J Physiol Heart Circ Physiol. 2002 Oct;283(4):H1462-70

Further reading

Cardiac rehabilitation NICE guidelines  : Myocardial infarction: cardiac rehabilitation and prevention of further cardiovascular disease 2013

 

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Now , some one wanted to know,  Can we diagnose unstable angina without Chest pain ?

Crazy question isn’t , Angina by definition  should have chest pain .There is nothing called silent angina , only silent Ischemia  .

  • We know Ischemia can occur silently .
  • We also know STEMI can occur silently (About 10 % of MI do occur without any symptoms )
  • If STEMI occurs  silently  why not UA/ NSTEMI combo ? (Collectively called as  NSTE-ACS)

The debate goes like this .If stable angina can present with equivalents ? what prevents  “Unstable angina”  to present with  Anginal  equivalents without chest pain ?

If  a diabetic patient who had a silent MI in the past  . . .  subsequently  experience  severe episodes of resting ischemia  , will he feel the pain , that is supposed to occur  with his  “unstable angina”  or not ?

Hmm , difficult to guess right,   So it seems highly plausible  UA/NSTEMI  do  occur silently ! Literature hasn’t looked into this specifically. Chest pain is built integral  into definition of UA , infact it is a symptom  complex rather than an disease entity by itself, while NSTEMI is ECG and enzyme combo ! Making the term  NSTE-ACS  look  perfect.

Any other technical explanation ?

The concept of Ischemic cascade says angina occurs last, well after biochemistry , wall motion defect and ECG , hence its distinctly possible for UA/NSTEMI present to be painless !

Final message

Anginal pain perception is related to intactness of neurogenic circuits and also probably the severity of Ischemia.If full thickness myocardial necrosis can be painless in few, nothing prevents from an episode of UA/NSTEMI  be truely painless .

Clinical implication of this conundrum

Can we admit a patient as UA/NSTEMI with out chest pain ?

Yes, it would seem so .

No, we can’t .

Indeed we can , if ECG changes are there .

No, we can admit even with normal ECG if its real unstable angina.

This is the crux of the problem in ERs all over the globe. Our knowledge base is simply not good enough. Every one of us has seen Troponin positive silent NSTEMIs ! but . . . to me still something is missing in the link .

Modern day approach 

Pain or no pain,any  fresh ECG changes ( Both T and ST shifts*) should be rushed to cath lab.Whenever you are not sure .Always better to err on the side of over investigation.That’s the mantra ! So ,you do an Angiogram , find an Incidental intermediatroy lesion which may not be responsible for the ECG changes but you are compelled to go after it FFR//iFR , OCT, IVUS and so on !

*There is huge list of non Ischemic ST/T shifts in ECG that can be read elsewhere .

Counterpoint

Can’t agree with this article. Foolish to diagnose UA without chest pain. Never  treat ECG  in isolation unless its a convincing  ST elevation or depression with clinical input and thorough scrutiny of  past record . Realise , how important is  the basics principles of medicine taught  by Oslers and Cushings a  century ago.

 

 

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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.

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Hot debate in STEMI

Acute total obstruction (ATO) of coronary artery is an emergency .Opening it  by pharmacological or catheter is the  standard ( logical ) protocol.However, time plays a crucial role in this coronary re-perfusion game.It can either be a sure shot of success or end up in total spoilsport. One more issue as important as time is from the overflowing scientific data  fired  by different regulators  in conflicting directions  (Also called knowledge) .

What to do with STEMI coming late ?

  • ATO with cardiogenic shock is an  absolute emergency at any time.
  • Symptomatic ATO  other than CS beyond 24 hrs still  considered  emergency for most.(Symptom should be true angina )
  • Hemodynamic instability is misunderstood term . Stabilizing it medically is not forbidden.

Asymptomatic stable ATO  beyond  24-72 hours can be  semi emergency, true emergency or as cool  as a cucumber depending upon the cardiologist’s wisdom , experience or inexperience  and the  Institutional Integrity !

*Please be reminded ,LV dysfunction is not an absolute indication for urgent intervention unless it is due to ischemic dysfunction attributable  to a critical non IRA lesion

When does a ATO become safe CTO ?

1 month , 3 months, 6 months ?

Why we are  not defining a sub-acute ATO ? or CTO in transition   ?

Is living peacefully with sub acute ATO or CTO a coronary crime ?

We don’t require a debate , whether these  questions are worth answering  or not !

Final message

Though cardiac professional  are committed  to open up occluded arteries to save  lives , reality is repeatedly teaching different stories ! The greatest danger of keeping an artery open( In disputed indications ) is the newly conferred risk of sudden closure and the attendant  unpredictable aftermath !

Or should we conclude : Living with CTO is ok , but don’t intentionally create one by denying PCI in late  post STEMI ATOs

Anti-thought

Arguing closed artery is better than an open artery is straw man argument and inability to interpret positive things in science.  However it may still be right  when science suffers  from hostile incursions from non academic forces.

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.The  forgotten “Gem of a study” from lancet 2002 .

The fight between Primary angioplasty and thrombolysis was actually over in 2002 itself. But the cardiology community failed to ,( rather reluctant ) to accept the truth. The issue is being dragged without any useful purpose (for the patient !)  still trying to keep up the non existing superiority of pPCI.

A bolus thrombolytic agent (TPA/RPA) or even streptokinase  can do almost the same if not better than a highly complex procedure called  Primary PCI with lots of logistics issues and most important an unacceptable early procedure related  hazard.

Timely lysis can kick pPCI out of the ring . . . in three aspects with 100% certainty !

1.If symptom to TIMI 2/3 flow in IRA is the true parameter of success .pPCI can never ever come closer to pre hospital lysis.

2.The poor lytics do not differentiate in the efficacy . It simply acts whoever administer it. While results of pPCI are never reproducible and lots of expertise involved.

3.Thrombolytic agents never need to bother  about the complexity of lesions , (or  where is the IRA dilemma ? Is it a CTO or ATO confusion etc ) for the simple reason it doesn’t need to think before acting. It does its job fast.

What did CAPTIM prove ?

  • It proved pPCI has no mortality advantage over pre hospital lysis.
  • Perhaps the most Important conclusion from CAPTIM is pre hospital lysis significantly reduced  number of new onset cardiogenic shock . This alone nullifies the self inflicted pseudoscientific delay wasting the golden hour in the process ! (By the way who fixed the arbitrary acceptable delay conferred to pPCI of I hour .The whole evidence base for this delay to be scrutinised in view of CAPTIM !)

Final message

It is an irony,  a simple intravenous push of a drug (Thrombolytic agent)  very early after an STEMI can save many patients and reduce complication rate .But because it is simple ,it is considered  inferior .

Probably the only role for pPCI is high risk complicated STEMI at presentation or after an attempt of lysis has not stabilised the patient.(Where its referred to as Pharamco Invasive strategy )

2018 update

This post was originally posted in 2008. Now as I see this in 2018 . It is shocking  to know we haven’t  learnt any lesson from this study for 16 years since its published.

In this era of medical  commerce and  simple ,cheap ,and effective treatment can never compete with  sophisticated , glamorous , less effective  treatment modalities !

Read the full version of CAPTIM and comments

Comparison of Angioplasty and Prehospital Thrombolysis in Acute Myocardial Infarction (CAPTIM) study group, are published in the September 14, 2002 issue of theLancet.

Primary angioplasty “no better” than prehospital fibrinolysis: CAPTIM

London, UK – In a finding that would appear to go against the swelling tide of support for primary angioplasty as the treatment of choice for acute MI, investigators comparing primary angioplasty with prehospital administration of alteplase with rescue angioplasty have concluded that the 2 strategies are comparable. The results, from the Comparison of Angioplasty and Prehospital Thrombolysis in Acute Myocardial Infarction(CAPTIM) study group, are published in the September 14, 2002 issue of theLancet.1

“Our findings indicate that primary angioplasty is no better than prehospital fibrinolysis followed by transfer for possible emergency coronary angioplasty in patients presenting within 6 hours of an acute myocardial infarction,” the researchers, led by Dr Eric Bonnefoy and Dr Paul Touboul(Hopital Louis Pradel, Hospices Civils de Lyon, Lyon, France), write.

However, they point out that cessation of funding during the trial resulted in a lower-than-expected enrollment, 840 of 1200 planned patients, reducing their statistical power. “The CI (confidence interval) for the primary end point shows that there could be a real difference in the treatment effects,” they write.

Still, the researchers feel their conclusion is valid. “This was and is for us a very pragmatic question for our care system in France,” Bonnefoy told heartwire. “Is our current management, with prehospital thrombolysis with transfer, in a time when primary angioplasty is promoted as the best-of-the-best treatment, still sufficient? Even if the power of the study is lower than expected, we think that we have our answer, and we can go on with that practice.”

The strategy also means less strain on their cath labs, Bonnefoy added, since only 1 in 4 patients underwent rescue angioplasty. A cost analysis comparing the 2 strategies is currently being carried out.

Earlier thrombolysisPrevious studies comparing primary angioplasty with in-hospital thrombolysis have shown a “definite, albeit modest” benefit of angioplasty over thrombolysis, with lower rates of recurrent infarction and higher patency rates, Bonnefoy et al write. However, it does impose additional treatment delays, and “delay to treatment is an essential consideration for any revascularization strategy.”
In France, where this multicenter trial was carried out, ambulance crews include a physician, and so thrombolysis with intravenous tPA is possible in the prehospital setting. In this trial, they randomized MI patients to either prehospital administration of accelerated alteplase or primary angioplasty and transferred all of the patients to a center where emergency angioplasty could be carried out if it were determined that thrombolysis had not been successful.
The primary end point was a composite of death, nonfatal reinfarction, and nonfatal disabling stroke at 30 days, with analysis by intention to treat.
Of the 840 patients, 419 were randomized to prehospital fibrinolysis and 421 to primary angioplasty. Rescue angioplasty was used “liberally,” they write, in 26% of patients assigned to fibrinolysis.

Time to treatment, as expected, was longer in the primary angioplasty group: the median delay between onset of symptoms and treatment was 130 minutes in the prehospital fibrinolysis group, and time to first balloon inflation was 190 minutes in the angioplasty group.

At 30 days, there was no significant difference in the primary end point between groups. Overall mortality was lower than expected, they note. Deaths were fewer in the prehospital thrombolysis group, but mortality was not significantly different between groups. There was a trend toward less reinfarction and less disabling stroke favoring the primary angioplasty strategy.

CAPTIM: Primary end point

Outcome    

 

Prehospital fibrinolysis    

 

Primary angioplasty    

 

Risk difference (95% CI)    

 

p    

 

Composite end point 8.2% 6.2% 1.96
(-1.53-5.46)
0.29
Mortality 3.8% 4.8% -0.93
(-3.67-1.81)
0.61
Reinfarction 3.7% 1.7% 1.99
(-0.27-4.24)
0.13
Disabling stroke 1.0% 0 1.00
(0.02-1.97
0.12

To download table as a slide, click on slide logo below

Among secondary end points, the researchers noted a nonsignificant trend toward a higher frequency of cardiogenic shockthe most common cause of death in this studyin the primary angioplasty group, noting that cardiogenic shock between randomization and hospital admission occurred only in that group.

The CAPTIM results were first presented at the European Society of Cardiology Congress in September 2001 and reported by heartwire.

 

Strong wordsIn an accompanying commentary, Dr Gregg W Stone (Lenox Hill Heart and Vascular Institute, New York, NY) calls the CAPTIM results “the latest salvo in the ‘primary PTCA vs thrombolytic therapy wars’,” a “well-designed and carried out” trial.2
“Unfortunately,” because of funding issues and slow enrollment, the trial ended before the planned recruitment of 1200 patients that would have been required to show a 40% reduction in the primary end point with primary PTCA, he writes. “Nonetheless, the results demonstrate a trend toward a 24% relative reduction in the occurrence of adverse events favoring the interventional strategy, driven by strong reductions in reinfarction and stroke (which would be expected, after all, to be largely independent of reperfusion time),” Stone notes.
He attributes the lack of mortality benefit from primary angioplasty to the lower-than-expected mortality risk in this population, since the survival benefit of primary angioplasty is seen primarily in the highest-risk patients, the elderly and those with anterior MIs or shock. The lack of mortality benefit, though, “does not diminish the clinical relevance of fewer strokes, reinfarctions, a reduction in urgent revascularization procedures, and the shorter hospital stay” seen with the interventional strategy in this and other studies, he writes.
Perhaps the most novel finding is the reduction in early-onset cardiogenic shock with prehospital thrombolysis, a result that “adds fuel to the fire calling for facilitated primary PTCA trials.” However, several trials of the combined approach to date have shown it to be either inferior to or no better than primary PTCA, he notes. Even in CAPTIM, prehospital thrombolysis was supported by rescue angioplasty in 26% of patients, and Stone speculates these patients may have been “better off” if they had simply been transferred for routine immediate primary PTCA.

“Thus, until the large trials of facilitated PTCA are completed (none of which have even begun enrolling), the best therapy for most patients with evolving AMI should no longer be debated; administer antiplatelet therapy (aspirin, a thienopyridine, and possibly abciximab), withhold thrombolytic therapy, and transfer the patient for primary PTCA, regardless of whether the nearest catheterization suite is 3 floors or 3 hours away,” Stone concludes.

“To do less should no longer be considered standard care. Strong words, yes, but it is time for a wake-up call.”

 

CAPTIM researchers respondAsked to respond, Bonnefoy pointed out that “Dr Stone is surely a primary angioplastician and very convinced, but it’s quite ideological. CAPTIM is quite pragmatic. His arguments are acceptable, but they are not convincing; that is his opinion rather than scientific data.”
Bonnefoy asserts that no study has clearly demonstrated the superiority in terms of mortality of primary angioplasty over prehospital thrombolysis. “And in CAPTIM, we have the surprise and intriguing observation to have lower mortality in the prehospital thrombolysis groupit may be hazard, but it is present.”
Moreover, while high-risk patients may benefit from primary angioplasty, high-risk patients do not represent the majority of the MI population. In patients such as those in the CAPTIM study, he said, “our conclusions are quite valid.”
 

 

 

Sources
  1. Primary angioplasty versus prehospital fibrinolysis in acute myocardial infarction: a randomized study2002; 360:825-829
  2. Primary angioplasty versus “earlier” thrombolysis–time for a wake-up call2002; 360:814-815

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