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Posts Tagged ‘cardiomyopathy’

It is a well known fact  ,   CABG and PCI  provides immediate relief  for patients with angina ,  which is refractory to medical therapy. Of course , this happens only if a critical occlusion of  at least one epicardial coronary artery is  opened . It need to be realised ,  angina  due to  microvascular  disease can not be cured by maintaining  epicardial  patency .

While angina  relief is prompt ,  dyspnea is not ! . If we  believe,  opening  up a  coronary artery  in a patient with LV dysfunction will  restore the LV function  ,  it  is grossly mistaken !

Why is it so ?

Angina  relief requires  simple  restoration  of  oxygen supply and correction of local ischemia .  This happens without any issue as the blood  seeps in to the ischemic cells and soothes the ischemic nerve fibres that trigger the pain signals   . While  ,  for LV function to improve , the blood flow has to be converted to mechanical activity in the form of myocyte actin/myosin interaction. For this,   there need to be an intact  cellular contractile mechanism . The myocyte architecture should be appropriate .In post MI ventricles we know there is  zig zag  orientation of myofibrils due to myocyte slippage that interfere with mechanical recruitment . Further , integrity of  extracellular matrix  namely the collagen frame work is also vital . Note ,  angina relief  is not concerned with any of the above .

And now ,  we also realise  dyspnea  in failing ventricles  is vitally  dependent on diastolic function ,  which is also very much  impaired in ischemic DCM .There is little proof for  PCI/CABG  to correct the  molecular   mysteries in  diastolic dysfunction !

Dysfunctional LV means what ? (read the link )

It is a collection of  variety of myocardial tissues . Viz : Fully  necrosed , partially necrosed ,  ischemic viable, non ischemic viable, ischemic non viable, non ischemic non viable , Apart from this patchy necrosis, patchy ischemic, areas are common. Finally , necrosed segments   may  also be perfused normally by  spontaneous reopening of an IRA.

One can imagine the complexity  of events in these segments  once we do the  PCI /CABG . The response  is highly variable and unpredictable. The major concept we  , the physicians  believe or ( to be precise made to believe !) is  the  sanctity  devoted to  the viable myocardium .For  many us ,  it is considered a  holy  exercise  to identify viable myocardium in patients following MI and then revascularise them if  found to have significant viable myocardium (Atleast 20% of infarcted area )

A full 2 decades were lost or (shall  we   say wasted on this futile exercise !) as   we have since  realised most of the cardiologists do not follow this rule .

Now , even a scarred myocardium is revascularised in the hope of recovery .As such , we have reached a stage where  there is no contradiction for not doing a PCI /CABG   with reference to LV dysfunction.

Now every  patient  with post MI  LV dysfunction  is considered to  have  some amount of viable myocardium that is  fit   enough  for revascularization

Are we justified in doing  this ?

Many clinical  trials  have revealed  , the  recovery of LV function  in these segments  has not been consistent at all .

The most surprising discovery is  a viable myocardium need not  be ischemic   .It might get adequate blood supply either  from invisible collaterals or trickle of antegrade flow .  Hence an adequately  perfused myocardial segment can  still be   non contractile . This shatters the myth  that  revascularisation must have a dramatic effect on the recovery of contractility in all viable segments.

The other major finding is  ,  even ischemic   viable   myocardium ( documented by metabolic activities PET etc)  need not regain it’s original contractility  after the ischemia is fully corrected .

*reference for  both the above statements are available from variety of sources including real life experiences .(Type C evidence )

Final message

  • Do a PCI/CABG promptly for patients with refractory angina.
  • Never  advocate PCI/CABG  for  a primary relief of dyspnea .  (Never is a harsh word,  let it be  “use it  with caution ” ! and  the  patient  should be  revealed  the whole facts  about  what we know and what we do not know regarding the complex  hemodyanmic events  in  revascularisation   )

Counter point

If  the above statements are really true ,   How does PCI/CABG   help  relieving  dyspnea  and functional class  what is your answer for thousands of patients  with CAD and ischemic DCM who have greatly benefited from CABG ?

The answer could  be  simple , The revascularization  piggybacks  over the   medical management (which , these patients pursue vigorously)     like  ACEI,  statins, salt restriction, betablockers  , optimal diuretics and tend to hijack the credits from the poor  drugs !

Read a related blog

Revascularisation for ischemic DCM

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The term cardiomyopathy generally denotes a  progressive disease  in clinical cardiology.There was a time   diagnosis  of dilated cardiomyopathy (DCM )  was synonymous with a  delayed death sentence !  Of course , the situation has vastly improved over the years  with the availability of  new medical , interventional and surgical management. Still ,  there is no denying the  fact  ,  DCM continues to  have a grave outcome  especially when it occurs without any identifiable cause .

While we have  variety of aggressive DCMs , we also  have  patients with relatively benign forms of   dilated and dysfunctional hearts  which recover totally .

This reversible forms of DCM is observed in  the following  situations.

Hypertensive dilated cardiomyopathy . The left ventricle  in  some of the  patients with severe SHT  respond to the stress (Increased  after load) by dilatation rather than hypertrophy. This is especially common after an episode of LVF.  If we do an acute echocardiogram the LV function is severely impaired and the LV may  also be dilated. With good control of BP and fluid management the ventricle promptly return  to it’s baseline dimension. The recovery is complete in many . (The mechansim of LV dysfunction acute severe Hypertension is referred to as Pre-load /After load mismatch) Link to concept of Pre load mismatch .

* Note in the past these entities were not called as  cardiomyopathy .

Peri partum cardiomyopathy.

This is a serious disorder of cardiac muscles that occur during pregnancy  few months before  or few months after delivery  . There is correlation between PIH and this entity. Prognosis varies between very bad to excellent. Very few cardiac entities  have a  natural history like this one disease of women.Most of the pregnant women regain their original cardiac status within  year or so. It should be recalled there is high chances of recurrence in next pregnancy.

Alcoholic cardiomyopathy.

The toxic response to alcohol or the additive cobalt can result in DCM .There is overlap  between holiday heart syndrome and alcoholic DCM , where atrial fibrillation is the major problem. Wet Beri beri is the advamced form of clinical DCM that respond to vitamin B therapy.

Tachycardic cardiomyopathy.

This is also a common entity that occur during persistent sinus tachycardia or AF , thyrotoxicosis.Beta blockers are  of great use here.  Recovery is usual if the primary cause is correctable.

Toxic and drug related  reversible LV dysfunction

Adriamycin cardiomyopathy

Tako -Subot  Cardiomyopathy canbe termed as classic form of reversible  stress cardiomyopathy

Miscellaneous conditions

Diabetes and chronic kidney disorders are known to have a reversible form of cardiomyopathy

Some rare toxins  , scorpion envenomation , selenium deficiency can result in reversible DCM

**Ischemic DCM are partially  correctable in many , still  we don’t include it as cause for reversible DCM

*** Many episodes of acute myocarditis can have transient or short term LV dialtation and  dysfunction.they are classified as myocarditis .But there is little  difference (Except acadmeic . . .)  between chronic myocarditis with LV dysfucntion  and cardiomyopathy.

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How will you refer to a ventricle which is not dilated but still has severe global contractile dysfunction ?

Traditionally cardiomyopathy is classified as

  • Dilated (DCM)
  • Hypertrophic(HCM)
  • Restrictive (RCM)

But there is large group of pateints who do not show any of the above features and still have global hypokinesia  contractile dysfunction. this group has been largely ignored .It could constitute up to 25%of all cardiomyopathy.there can be some overlap between non dialted cardiomyopathy and RCM.

We report our experience here with

non dilated cardiomyopathy click to download PPT

non dilated  cardiomyopathy

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Chronic renal failure and CAD are common companions.Severe CAD  in patients with renal failure  pose an imposing task on the treating physicians.CABG  and kidney transplantation  both are major interventions.When a patient  requires both the decision making becomes much more difficult.

The possible  choices are

A. Do CABG first follow it with renal transplant .

B. Do  renal transplant first follow it with CABG.

C. Do CABG first  and  defer transplant &  advice life long dilaysis

D.Do  renal transplant and offer medical management / PCI for CAD if feasible.

E.Simultaneous CABG & renal transplant is a remote possibility .

F.In terminally ill , combined cardiac and renal transplantation is the ultimate option. (Possible in very few centres in the world)   

G.In severe co-morbid condtions avoid both and support life. Success is not in completing   the procdeures but in providing useful life !

Among the options the most prefered worldwide is option no 1. This has a caveat. If angina is dominant  CABG should precede transplant. If cardiac failure is dominant the issue need further scrutiny.

Given a situation ( DCM & End stage renal disese) , your patient could  undergo only one procedure,  which will you prefer ?

              This again is highly emprical but logic could still be applied. Never do  CABG with a sole  aim of improving severe LV dysfunction in ischemic DCM .It happens only in  journal articles & major clincal trials!.Of course mitral valve correction and LV reduction surgery might help.But in a patient with  renal failure prolonging the CABG on table time , with add on surgery is highly risky. So it would be logical to think intensively  for  postponement of  the CABG in a patient with class 4 cardiac failure and renal failure. Do only the transplant .

 What is the impact of end stage renal failure  on LV dysfunction ?

 End stage renal failure has a great adverse impact on LV function. Many times it is reversible.We will never ever know, if you do a CABG first on them. So always think twice or even thrice before voting  on this vital issue . Correction of renal impairment can improve the cardiac status dramatically in some.

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