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Posts Tagged ‘acute myocardial infarction’

Answer: Do  coronary angiogram  for all patients  who had suffered from an acute myocardial infarction* ( Forget about all those mulitpage ACC/AHA  guidelines !).

For an  interventional cardiologist ,  it is often  considered a crime to  follow a conservative  approach !

*Caution This one line guideline is not based on scientific fact  but reality based . Ideally one should identify  high risk subsets among the patients who had an AMI .Patients who had complications during the MI get immediate CAG. Others need  a focused LV function asessment ,  pre discharge  sub maximal excercise stress test or perfusion studies .But this concept has been  virtually replaced by pre discharge coronary angiogram for all ,  in many  of the centres in the world.

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Differential response of thrombolysis between left and right coronary system

  • Thrombolysis is the specific treatment for acute myocardial infarction. ( Privileged few , get primary PCI))
  • Failed thrombolysis occurs in significant number of patients ( 30-40%).
  • Persistent ST elevation  120 minutes after thrombolysis is best indicator of failed thrombolysis.
  • It has been a consistent observation  failed  thromolysis  is more frequent in anterior   or LAD myocardial infarction.

In a simple study we have documented  patients  with inferior MI  rarely had persistent ST elevation and thrombolysis  was   successful in vast majority  of  patients  ( Except in few patients associated lateral MI)

 

The mechanism of better thrombolysis in right coronary artery  is simple.The success of thrombolysis , apart from early time window , is directly correlated with pressure head  and the duration of contact between the thrombolytic agent and the thrombus. In right coronary circulation the  blood flow is continuous ,  occurs  both in systole and diastole that facilitates the maximum delivery of the thrombolytic agent . Further there is a favorable  pressure gradient  across RV myocardium  as the transmural occluding pressure across RV is considerably less then LV myocardium.

This paper was presented in the  “Annual cardiological society of India scientific sessions”

at Chennai, Tamil Nadu.India December 2000

Click to down load PPT full presentation

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Is it a crime to do a plain balloon angioplasty in 2008 ?

Plain balloon angioplasty,   the greatest  innovation in   cardiology  when it was introduced in 1977 in a Zurich cath lab , has now become an  ugly  word for most of the cardiologist !

Why this turn around ?  Has technology ,  really overtaken a great procedure and made it obsolete now ?

The answer is a definite ” No”

The restenosis which was the villian in the plain old angioplasty has never been overcome even today. Stents initally used as a bail out procedure during  abrupt closure , later it was used conditionally, followed by provisional stenting and now in 2008  we are made to believe  it is mandatory.

When we realised , bare metal stents are equally  bad (If not slightly better ) in arresting the restenosis drug eluting stents came into vogue with a big bang in 2002. It was projected as the ultimate breakthrough in interventional cardiology and  in 5 years the truth was exposed and it not only failed to prevent the restenois but also had a dreaded complication of acute stent thrombosis.

Now we know , metals  inside a coronary artery  carry  a life long  risk of sudden occulusion , and we talk about biodegradable stents (With poly lactic acid ).

 Common sense ( Unscientific truths)  would suggest

Plain balloon angioplasty still has a major role in our global  cardiovascualr population.

Since restenosis is the  only issue here, ( about 30% )  we can choose patients in whom even if restenosis is likely to happen  no major harm is done . A vast majority of chronic stable angina patients  fall in this category.

Aggressive lipid lowering with plain  balloon angioplasty has never been tested properly . In future also it is unlikely,  such trials will be done as it would be considered unethical . But that would be a premature conclusion.

The other major issue is the cost of stenting , the procedure of PCI/PTCA  has become unaffordable for most of the population in developing countries .The primary reason being the PCI without stenting is considered  ” A untouchable” . If only we remove this stigma from the cardiology community   a signiificant population will be benefited.

A patient with chronic stable angina treated with POBA ,if develop further angina after few years , he  is likely to get a recurrence of  relatively safe  stable angina.  While in a post PCI patient  any angina after the procedure becomes a unstable angina ( Braunwald classification)  and requires emergency care . Angina in a  stented patient is can not be taken lightly as  the the course of angina is unpredictable .

POBA in primary PCI ?

Many may think it is a foolish idea . It has been found many times,  when we rush the pateint to   cath lab after a STEMI  we are in for a surprise !. About 30% of times it is a very complex lesion profile  like diffuse disese,  tight bifurcation lesions , loaded with thrombus or a left main disese.

We fail to realise a basic  fact  , the  initial aim of primary PCI is to salvage the myocardium ,and the next comes the prevention of restenosis . It may even , be argued salvaging  myocardium is the only aim ! Myocardial salvage sould be done urgently . And even  removing the thrombus and opening a IRA can be suffice in a patient who is crashing on table.  Of course stenting can be done whenever possible. But for IRAs which has complex anatomy attempting a perfect stent PCI   (Some may require more than few stents)  as an emergency procedure invariably affects the outcome. One should spend  shortest possible time  inside the  illfated coronary artery. Prolonged manipulations within the coronary artery in an unstable patient  aiming at  longterm patency of an IRA  is to be avoided .The pending procedures can always planned in a next stage. 

Final message

So it is not a crime to think about plain balloon  angioplasty  in some of  our  patients  with acute or chronic coronary syndromes .  Hope Gruentzig  is listening from the heaven and hopefully agree with me !

Dr.S.Venkatesan, madras medical college, chennai, India .

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