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Archive for the ‘acute coroanry syndrome’ Category

William Heberden first introduced the term angina to the medical community in 1772. His descriptions became immortal. Still, no one would ever know what was the angina-related artery, Heberden was alluding to.

Now, some jobless cardiologist is asking this question after 200 years. How is angina from the LAD system differ from the RCA  system? or let me put it another way, How does angina of anterior circulation (LAD) differ from posterior circulation (RCA/LCX)? Though there is distinct hemodynamic profiling of RCAvs LAD ACS, surprisingly, cardiology literature does not answer the chest pain aspect of it. One rare study, done  4 decades ago throws some light

Here is a curious little study, with a simple & crisp conclusion.

chest pain and IRA localisation angina LAD angian RCA

It concludes, that LAD angina rarely radiates to JAW or epigastrium. While RCA angina relay radiates to the left shoulder.

So, why does this happen?

What I could guess is the ubiquitous vagal fibers that travel in the posterior aspect of the heart, and carries pain signal directly up to the jaw whenever these areas become ischemia. LAD is less likely to irritate the vagus. Of course, there can be a definite overlap.

OMG, give me some time to keep in touch with  basic science 

Now, fellows of cardiology, please take a  pause from your regular aggressive cardiac cath lab workouts and get a break at least once in a while. How does the ischemia of myocardial tissue generate pain? Why it is severe in some, trivial in others, and even dead silent in some, 

The chest pain genesis is initiated by sensory electrical neural action potential, that captures the epicardial neural plexus first, switching over from somatic to the visceral pathway and trespassing the para ganglionic plexus and traveling further to the spinal cord. Where it may collide with other incoming sensory signals ascends in specific myelinated and non-myelinated neural cables, reaching the brainstem, interacting with local nuclei, and finally reflecting on subcortical and cortical pain matching centers.  We haven’t yet located the exact center for anginal pain. (Perithalmic and amygdala could be closer to real centers) 

So, it is a really complex sensory world yet to be understood fully. Mind you, I haven’t touched upon the neurophysics of referred pain, linked or clandestine angina.

  • What is the effect of cardiac denervation, autonomic neuropathy, or on the perception of chest pain(Does a quadriplegic feel angina ? or post-transplant heart immune to angina ? (Gallego Page JC,Rev Esp Cardiol. 2001) 
  • Is it biochemical or neural, can substance P in blood cause pain hitting the amygdala? 
  • Will hypoglycemia and anemia cause angina due to lack of glucose and oxygen?
  • Finally, how is Infarct pain is different from ischemic pain (Ischemic)

Where do get the answer to these questions?

This paper from Dr. Robert Formean(Ref 2) university of Oklahoma is just the best source I think, to explore and understand the topic. (Reading time 60 minutes: Let me tell you, it is worth more than a time spent on an insignificant angioplasty of painless PDA lesions)

Final message 

So, what have you learned from this post? Does this question about angina matter at all? Surely not. in this space-age cardiac care where we are right inside the coronary even before we listen to the patient’s complaint properly. We are always at liberty to do what we want( or love) to do. But, the urge to understand the foundations of clinical science is the last remaining hope, that will keep the specialty of cardiology enchanting. 

Reference
 
 
A comprehensive reference for the genesis and signal processing  of chest pain 
 
 

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“We have a 24/7 cath lab with an open door policy. Our cardiologist arrives at 15 minutes’ notice. Door to balloon time is less than 60-90 minutes”, 

“Great, so, you can always offer a successful treatment for STEMI”

“No, that we can never guarantee.” 

 “Oh, It Is not the answer, I  expected”

“I agree, it sounds disappointing, but. truths are less pleasing. What I am trying to say is, there are a number of factors other than the availability of a grand cath lab and agile and effortless hands, that try to reperfuse the myocardium in distress.  I agree, we do save lives occasionally in a dramatic fashion. Recently we resuscitated an almost dead man with CPR and ECMO-guided PCI. But, most times it turns out to be just a customary ritual that takes us to the legal and therapeutic  endpoint* of STEMI management”

*Both salvage & non-salvage

“I didn’t get you, Can you explain further?

See this curve and try to understand it yourself. (I would say, this is the ultimate curve to understand in the entire field of coronary care)

Can you guess what will be the outcome for C to B, or B to A ?  In the real world, a substantial number of interventions take place at an Invisible point E beyond A  Source: Gersh BJ, Stone GW, White HD, Holmes DR Jr. Pharmacological facilitation of primary percutaneous coronary intervention for acute myocardial infarction: is the slope of the curve the shape of the future? JAMA. 2005;293:979–86

Slippery slopes and edgy Interventions

At what point the patient lands up in the curve & at what point the interventional cardiologist intervenes (or does not intervene) matters the most. 

The gaps between benefit and harm can change in a few strokes of time. The reperfusion tamasha can get more curious if we realize both the slope of the curve & its absolute position are dynamic. It can shift to the right or left with reference to the patient’s Initial medications, MVo2 confounders, the quantum of collateral circulation, myocardial hypoxia threshold,  previous ischemic episodes, conditioning, etc. So, basically, we are reacting to events and trying to rush up things. Don’t worry about all this. Cardiologists have every expertise and equipment to tackle untoward events.

STEMI is not always myocardium under fire

Finally, and most importantly STEMI, though a cardiac emergency. all should not be equated with the house(myocardium) on fire analogy. It can also be a spontaneously aborting, settling, or evolving, self-extinguished controlled fire, and the myocardium may take it easy. All that it requires is some deep ischemic slumber. Don’t try to poke it with all our violent hardware at one go in the name of salvaging. What is required is proper CCU care to take care of potential arrhythmia, angina, or failure. One may create more damage if trying to dowse non-existing flames furiously, which expresses in the form of reperfusion Injury and no-reflow to the myocardium. (Which might have reperfused at leisure without experiencing the injury.)

It is worth pondering over this question.

Why does even an apparently well-timed primary PCI of IRA leave behind a significant LV dysfunction or even a  scar? This is a clear case of “successful PCI failed reperfusion syndrome”. It is better cardiology community defines successful primary PCI with reference to predischarge  LV function, not on the IRA patency and mystery endpoint called TIMI 3 flow.

Final message

Cath lab doors that are open 24/7,  with experienced cardiologists may matter little if we are double-blinded against multiple scientific and non-scientific factors that are visible as well as invisible. 

Counterpoint

How good is late PCI? Are you not aware benefits of the open artery hypothesis?

You need to learn a lot man, before posting such posts.

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Just roll over the virtual marker along the coronary lesion to get the underlying flow ratio. Blue is an absolute normal segment. Green is ok, orange and red slow-moving coronary traffic jam zones. it’s just like drawing a google map showing life traffic. No wire, no adenosine FFR comes inbuilt in every angio shot. Looks great Isn’t it? This is called QFR. Quantitative flow ratio derived from routine coronary angiograms. It can also guide us to find the optimal sites of both proximal and distal stent landing zone in the best physiological manner.

Which company makes this ?

Any studies done with QFR ?

FAVOR 2 study was reported in TCT. This modality is expected to evolve.

Final message

Whenever possible every anatomical lesion in the coronary should be substantiated by physiological parameter and possibly coronary Imaging to know plaque morphology and vulnerability. Though it is wishful thinking, still for all logistic reasons, most of the real world stenting will be based only on the blind anatomical luminogram.

At this point, please let me utter a non-academic hyperbole. Even a casual query to your beloved patients about their true symptoms and exercise capacity shall make these ultra-modern coronary physiology studies redundant in many. A well-performed and well-interpreted stress test is a good, objective, non-invasive indicator of coronary flow across lesions. It is wise to keep this as a basic clinical foundation in the evaluation of CAD, even as we continue to learn and forget half evolved modalities with rapid expiry dates like FFR, IFR, CT-FFR. QFR shows some promise though. Please watch for next in line coronary physiology – OFR, Optical flow ratio from OCT run through.

Reference

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Coronary collateral circulation is one of the major determinants of symptoms and outcomes in chronic CAD. But, we generally shrug off the value of coronary collateral circulation in acute coronary syndrome. The fact is, it has a myocardial mitigating effect following sudden total occlusion.

When does it appear? We did a small analysis (PDF version)

We found it is noted in 25% of patients. With reference time of appearance,  6% had it within 12hrs and in few, it was noted as early as 6 hrs. One caveat is,  we may not know whether its preexisting collateral due to chronic multivessel CAD. I am sorry to note this study did not address the outcome analysis. We however documented patients with good collaterals had negligible wall motion defect and near-normal function post PCI. Some of you can pursue research in this area. 

Potential role of collaterals in ACS

  1. It limits the infarct size
  2. Keep the myocardium alive and give us time to intervene
  3. Can converts a potential Q-MI to non-Q MI
  4. Possibly prevent primary VT/VF and hence dreaded sudden death in early STEMI
  5. Prevent early adverse remodeling of the left ventricle.

When these points appeared just my assumptions, Dr. Ali Aldujeli, (Lithuanian University of Health Sciences, Kaunas) in his presentation, at TCT 2020 confirms many of them are  Indeed true

Final message

I agree, in the era of instant gratification with primary PCI,  relying on coronary collaterals may appear a lesser professional virtue. Still, we may need to respect nature. Many times it bails us out.

Current update 2020

Alsanjari, O., Chouari, T., Williams, T.,  Angiographically visible coronary artery collateral circulation improves prognosis in patients presenting with acute ST segment‐elevation myocardial infarction. Catheterization and Cardiovascular Interventions.  Volume96, IssueSeptember 1, 2020 Pages 528-533

 

 

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Science is a journey in pursuit of truth. Hence, we search for it again and again.  (Thus, recurrent search becomes Re-Search)

As we try to progress in our knowledge towards absolute truth,  we need to admit our errors first. I think, one such error is blinking right in front of us in the vibrant corridors of coronary care and cath labs every day!  It is about the definition with which we deal the success of primary PCI. (A supposedly revolutionary acute coronary therapeutics  this century)

Waiting for the day . . . when all those fancy primary PCIs that leave the myocardium hurt (& retire ) with significant LV dysfunction to be reclassified as clear cases of primary PCI failures.

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*ISCHEMIA trial breaks not in NEJM or Lancet but in Washington Post and Wall street Journal

After three decades into cardiology profession, one thing is very clear. We work so hard to create pseudo-knowledge and struggle with it for so long and feel awkward and guilty to come out of the mess. But we have to  . . .  in the overall interest of mankind, isn’t?

We aptly call the whole process as continuing medical education, but in the melee, often we ditch some of the precious gems as obsolete. (This tempts me to suggest discontinuing false education is also an option for medical knowledge seekers !)

Confucius has something to say about this issue , which appears more relevant to the medical profession in current times.

Postamble 

We don’t know what’s in store for 2020

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GettyImages-865142952-5b5eef884cedfd0050112fa6

Charles river esplanade ,Boston* : A healthy middle-aged man who was jogging quietly, while his heart was under intense scrutiny by the bionic eyes of Apple i-watch’s smart patch electrode. Suddenly, it detected some bizarre ST segment fragmentation (Seems it can predict in advance , Ischemic signals 10 minutes prior to onset of ACS ) The built-in cosmos direct GPS instantly alerted & summoned a titanium powered Space X drone that pulled the patient from the riverside to the nearest human wellness port .

EHANG 184

It dropped him through a remotely accessed split glass roof right inside the hybrid heart lab, to find , men and women chatting with flattish Artificial intelligence panels who readily allowed the robotic arms to hug the patient which engaged the coronary artery pushing radiation free magnetic gas found nothing inside and what would become a perfectly normal human coronary artery .

An amused resident robot gently plucked the patient from the cath table with sheepish laughter and called for another drone to drop the patient exactly in the same place from where he was picked up.The healthy hearted patient thanked the doctors profusely and continued his routine evening jog across the Charles of course with a 16-minute delay!

Next day . . .

Event auditing firm medi-logic mind congratulated the entire cardiac team and its digital health hub for the quality of the network and completing this daring coronary rescue mission in 16 minutes. While the drone to hospital roof time was 3 minutes, the coronary artery visualisation time was perfect.The auditing team had a special mention about the astonishing capability of Apple time watch algorithm that made sure that the patient’s evening routine was unaffected in spite of this life-threatening non cardiac pseudo-emergency. The crowning glory was, the entire expenses amounting to 250000 dollors (after a special money back discount coupon for the first false alarm) were taken care by the patient’s virtual insurance blockchain payment gateway.

*You have just read the news that wasn’t – January 2030 AD

Now, back to reality,

Stumbled on this news clip from pages of Times of India, (20-6-2019) months after I wrote the above piece. I wondered the chase between fact and fiction is becoming  really a close race.

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Evening cardiac clinic is generally a relaxing place until an occasional patient  with vague chest discomfort present with this sort of an ECG .

He was a 68 y old hypertensive and was on Tablet Amlodipine .After a cursory look at his ECG , eyes wandered to look for some specifics. Suddenly ,my  ECG reading skill was stretched . Is it really LVH ? or Ischemia ? I asked for any old ECG which he couldn’t provide. I had to blink  more than a moment , before asking him to describe his chest pain in detail one more time . I got almost convinced it was not ACS  since he was having only localized pain over left side of chest. Still , I didn’t have the courage to send him home. An Echo was done.

Curious to know what the Echo showed ?

 

Yes , you also probably guessed right . It is LVH and there is no wall motion defect either.

How to differentiate between Ischemia and LVH ?

This is a common question asked in the board exams.There are number of ECG clues to differentiate the two .Mostly it will help  fellows  to pass exams. Academics rarely comes to your rescue when patients land with  chest pain  especially at odd hours.

Find the answer in this link

https://drsvenkatesan.com/2009/12/12/how-to-differentiate-lv-strain-pattern-from-primary-lv-ischemia/

 

Now comes the real twister , Does presence of LVH  exclude Ischemia in any way ?

Why can’t be ACS in a patient with LVH ?

When I posed these questions , some one suggested global longitudinal strain  with speckle  tracking to rule out ischemic wall motion defect, my resident suggested  high sensitivity Troponin and Ischemia modified albumin.

Whatever is the technological assistance , one thing  is certain,  we need to finally fall back  on patient’s symptoms . Unstable angina is neither an ECG diagnosis nor biochemical  or Echo diagnosis . (Its all about patient description about his angina , that clinches the  diagnosis !)

It remains a fact normal spot Troponin can never rule out  ACS on time ,( Even patients with unstable angina who  harbor  tight  LAD lesion can be both ECG /Enzyme negative )

When we are not sure ,the traditional coronary care dictum  shall operate .It demands admit, observe, with serial ECGs and enzymes. This protocol cant’t be followed strictly for a variety of reasons . We may have to rely entirely on our clinical Intuition accrued over the years.

A modern-day cardiologist might have a different dictum .The simplest solution in such situations is a diagnostic radial snap shot coronary angiogram .It is an easy way out  . . . , and avoids the trouble of spending wasteful minutes of personal conversation with the patient .The ethics of outsourcing history taking , patient record review or even clinical examination has pushed the definition of professional competence in coronary care into murky grey zone.

One more reason we should hesitate to rush these patient to cath lab is the detection of  incidental insignificant CAD (Which will loom larger than life when they are wheeled in from  ER)  that will  lead on to  further inappropriate chain of events.

How relevant is clinical acumen in modern era ?

Clinical acumen in medicine can never be taught in class rooms or read in text books. It is the innate ability to  combine  knowledge, experience ,skill  and  lastly (and most importantly) courage to ignore conflicting and pervasive data from new generation Investigations. Instead of helping us ,they often directly affect our increasingly vulnerable native medical cognition.

Even if some one is blessed with a good clinical acumen it seems to have little value many times as power of Investigations and fear of missing a event will prevail over it ! I have been victim of this phenomenon many times and not able to follow what my mind preach me !

What happened to this patient ?

I had to admit him against my  wish (Of course I was safe!)  He too got admitted reluctantly and was observed till morning , spent Rs 5000 for pack of investigations and stay , was discharged without any issues with a diagnosis of simple Hypertension and LVH.

The non academic bug  didn’t stop there  . . . again  contrary to my conscience  I had to suggest  optional coronary angiogram to rule out true CAD as a precautionary statutory advisory !

 

Counterpoint 

How do you know this is really not CAD  ? I won’t believe unless and until I see the CAG and its normal.

Ok, Let me post his angiogram if he decides to  undergo it.

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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.

.

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 !

Postamble

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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