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Posts Tagged ‘lancet’

Medical  research can be divided into few  broad  categories

  1. Basic science  research  in animal models
  2. Basic science  research   in Human
  3. Clinical : Bedside-  observational
  4. Clinical:  Epidemiological
  5. Community based long term data analysis
  6. Interventional -Drug /Device/Surgical

*Logically the  top 5  should  constitute  the bulk of research  ,  in reality    last one wins the race with considerable ease . Why ?

The important issues that  confront  today’s medical research  starts  right from the  “Aim” of the research ,  methods , materials statistics,  and  goes on  to   ethical issues , conflicts, futility ,  gimmicks  0f  publication  ,  marketing and ultimately left  for human assimilation .

(Read a related article in this blog   can  Aim of a study be wrong ?)

Data(s)  won’t  lie  . . .humans do  !

Science is nothing but collection of  facts ,  rechecking  the facts , and  finally confirming ,  they are indeed  facts. So medical  data collection becomes vital .  Data,  if  properly collected ,  wont lie.   Bias is always an issue in prospective trials. Further ,  and whenever and wherever  scientifically  motivated  human  beings interact with  data  the later   becomes a vulnerable  target and  get manipulated   for various reasons . (Read the famous article on data torturing  in  NEJM : I will link it soon  ) So blinding  becomes  mandatory   and it should  be total as some studies  tend  to  gain vision half way through !

Image courtesey : Jupeter images

Simplicity of observational studies.

We  give undue importance to RCTs . What we fail to understand is RCTs are required only  in selected situations in medical research (New drugs and interventions ) Meanwhile , we can do wonders with retrospective observational  data. These  data  can not be  manipulated  as the events  have occurred already and those people who collect or record the data  wouldn’t know this data is going to be utilized  for a study (This  , in fact  is  equivalent  to 100 % natural blinding and constitute a  real world study )

Observational  study can involve  patient behavior ,    disease behavior  , community impact, drug action, investigation modality , etc  . . .etc  . Your mind is the limit . Cost of doing a observational study is less but the impact on the society can be great .

Observing skills are the  biggest causality in modern medical times , This was  only scientific weapon of  our ancestors had , which they  used in an exemplary fashion .( Recall how Heberden described angina and Harvey taught us about circulation without even ECG and X RAY chest )

Fraud in medical research

Wherever big money is flowing corruption and fraud is unavoidable . . .at the  least . . .  we  should recognize it

( Many journals  just point out this possibility by simply displaying message of conflicts .They do not bother more than that  . . . just a warning message  )

Now in the modern scientific world  ,   even as the   genuine contributions   from our ancestors  left to  stare  the back of us  , we try to indulge in all sort  of unpleasant things.

In an audit against fraud in medical  research ,  it was found most of the fraudulent research happened with drug and device trials and few in basic science involving genetics and molecular medicine . It  was  rare to identify fraud in research involving purely clinical and  epidemiological  analysis .

Drug trials  need to be prospective . Vested interest can play  havoc in prospective data .There is a  thing called steering committee in all major studies   . . . we do not know what does the  word  steering really   mean .

There has been many  occasions  even well conducted studies turn out be  fraudulent . Now we realise many such studies are struggling to prove its worthiness .

In fact  it is argued every study before getting published   should undergo a  global ,  independent  trial   monitoring  board for genuineness  of the study . (Not the customary  peer review !)

Final message ( Sorry its  a  long one !)

We have a huge problem  here . I am afraid  we  haven’t even  understood ,  what  we  mean by medical  research !

For today’s   youngsters  medical  research means doing sophisticated  tests in nano- labs  , human genome  mapping ,  space age imaging modalities  or  involving a multi- billion dolor drug trials . This is absolute  falsehood.

What we need to do is   “search” , ” search”  ,  search again (That is   why it is called re-search )  for all those elusive  problems  our patients   face .Not only in their body , in their  home , in their community,  etc . Every  patient  teach us  few points,    observing and learning new things  and  publishing is  also an important aspect of  research .One can do  a instant   research in the crowded  OPD of a hospital   , in the wards , (What is the profile  of fever pattern in a winter season in your hospital ? does it reveal a new viral epidemic ?)

An ideal research  should  identify a problem and suggest a practical solution to a given problem .There are millions of such issue waiting for our attention in the bed side.  But what is happening  currently ? Current medical research is largely direction less ,  fueled by vested interest ,  makes  sure it avoids  all genuine problem areas !

Many studies  happen  based on  flimsy scientific   basis  .We are still  wasting our time to increase human HDL levels. ( Not with standing  the famous Torcetrapib fiasco  )   .Hundreds  of thousand of dollars   are pumped into this  research even after realising  only the  endogenous HDLs generated by natural methods like  exercise   are  the really  good HDL !)

While we do million dollar research   with a dubious risk factor called  high sensitive C reactive protein  ,   there is  no takers against number one killer disease of human kind  namely  “The  poverty” (WHO ICD codeZ59.5 )*

Let us prey   God  to instill common sense to all of us  . Patients  suffer with disease and we suffer from irresponsibility  or reduced responsibility ! It  makes us happy at-least few forces  like Lancet  , British medical journal etc are fighting lone war  against this  ailment  medical science is suffering .

*Please note :  http://www.icd10data.com   WHO labeled poverty as disease many years  back without much fanfare ! It is rarely mentioned in  any  graduate student**  medical text  in whom our future lies .  I do not know whether  Wars  and terrorist acts  been included as disease  or not !

**Our students  rattle about  about the  exotic  tick borne  Lyme disease happening once a year in remote hills ,    while  most will stare blank   when asked  how to diagnose and  treat  nutritional  anemia with  which millions suffer  every day !

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When we get contaminated with excess  knowledge , we lose our ability to think !   &  Common sense is the casuality . . .

Human beings differ from other forms of life by their sixth sense . Our planet is  few billion years old . Life came into existence over a million years ago .Our life has  evolved over many  thousands of years .The average life span of  human race   is  75 years . We need to realise , our life constitutes  only a fraction of our planet’s life (<.0000001% ) . A  may fly , which lives a life of  less than a  day ,   does it in style  , looking for the light  throughout  the night ,  says good bye ,  to earth by morning  leaving  it  unharmed . Actually ,  in terms of time , the life of the fly is  just a  fraction less than  human life span , when compared  to  our planet’s life !

When these children are  longing for food , some of  earthly humans go to  spend millions for  obesity surgery ! That is  the progress of knowledge driven society . . .

It is  extremely common to  experience the following  scenario  in any corporate hospitals of  both developing and developed country .A   uninsured  or half insured !  person is  refused entry into a hospital even for an  emergency care  while a wealthy person is lying comfortably watching TV in a five star suit of the same hospital after an inappropriate coronary angioplasty for  an   innocuous   lesion of his heart !

The irony is ,  in this short span  of  earthly life  ,  we want to prevail over the nature and conquer the planet . God is watching  this human  behavior silently . And he is smiling  . . .

With all our knowledge base ,  modern science  have done the maximum possible  damage to our  planet  .We have made many lives extinct. If  we  tend to  think , with the help of  6th sense  we can become immortal , it would be the ultimate foolishness. When every one of us ,  is  obsessed with our own  health  , we are deaf  to  the silent cries  of  our beloved planet earth .

Now , all of a sudden we realise all the accumulated knowledge & development has actually worked against us. We find our knowledge is dissociating our thoughts   and now , we are fighting  vigorously  over acquiring the rights to damage our planet  .

So it seems ,  the more we learn,  less wisdom we have  ! We may need to  learn important lessons  of living  from  all those  species   which  do not  boast to have  the  6th sense  !

Read a related article , excellent one published in British medical journal  nearly 2 decades ago

Knowledge disease BMJ. 1993 December 18; 307(6919): 1578.

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What are the fundamental  difference between randomised  studies and observational studies ?

New discoveries come from shrewed  observations made in bedside or labside  while ,  randomised studies evaluate these discoveries for it’s effectiveness or futileness  .

Let us realise ,  RCTs   primarily  never  contribute to  generation of  original  concepts or discoveries  ! .It is a  statistical tool to assess an observation .

Click below to reach the excellent knowledge  source on above  the issue .

PLoS Medicine: Observational Research, Randomised Trials, and Two Views of Medical Science

The fact that  observational studies are done with open eyes &  mind ,  it is  obvious it  demands  intense conceptualization and thinking .
Blinded studies  are  mechanical studies . It is pure statistical research . It requires  no thinking  , medical  mind , in fact one can do it with eyes closed as it is a strict protocol driven  , even a  non medical men  can do a  medical research , while it needs a  alert mind to do a observational study .

Observational studies , especialy  when done retrospectively  has  zero bias  as the case selection and  the potential intervention are completed even before the research question  is raised. In fact many of the  greatest medical breakthrough comes from retrospective analysis. Of course this has to be proved prospectively  preferably in a randomised fashion.

So , we the medical professionals ,  shall  do great observational  research with open eyes and mind and let the  the statisiticins do the outcome analysis blind folded .

If the core medical professionals are bothered more about  randomised blinded  studies ,which is  meant only for evaluation purposes , the  future of intellectual  medical research is  going to be in jeopardy!

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Why PCI  in   left main CAD is considered  an inferior modality than CABG ?

CABG is superior to PCI for the  simple reason it provides complete revascularisation virtually in all  patients with LMCAD , while PCI is possible only in a fraction of patients with LMCAD.

If  we take 100 patients  with left main  disease may be ten (At best !)   would be  suitable for PCI ! In other words PCI is contraindicated in vast majority of LMCAD  by technical criteria alone , while there can never be a contraindication for CABG in patients with LMCAD.(Except  when , comorbidity precludes surgery )

Why  PCI in  LMCAD difficult ?

It is  dependent on  technicalities

CABG does not tackle a lesion,  it simply avoids it  and by passes it ” No great brains required”

while PCI takes on the plaque frontally ,  in the dangerous  terrain of  left main artery  itself !

so,  much caution,  planing ,  logistics are required . Further ,  if there is a complication there is a potential

for catastrophe  as the only  supply line is cut off . This is the reason , cardiologists were worried to try this on

unprotected left main. (Protected LMCAD refers to left main disease following CABG  wherein atleast   LAD or LCX is  grafted )

Points to ponder in LMCAD

  • PCI is suited for isolated discrete LM disease.In realty  this is seen in less  than 5-8 % CAD.
  • LMCAD is very often associated  with  critical and multivessel distal CAD . So these patients will be candidates for CABG.
  • Left main ostium or LAD ostial  involvement makes PCI a tougher exercise
  • Calcification is more common in LMCAD that  again makes PCI difficult.

The following article in Feb 2009 is a major blow for proponents of  PCI for left main

http://circ.ahajournals.org/cgi/content/extract/119/7/1013

left-main

http://content.onlinejacc.org/cgi/content/abstract/51/5/538?ijkey=84c977d189e84327c3abbd4c1228de17dd99048a&keytype2=tf_ipsecsha

Final message

  • Conquering left main disease is an interventionist’s  ultimate dream.
  • But, before that they have  to tackle the bifurcation lesions .This is of vital importance, because 2/3 rd of left main  patients have  some form of bifurcation lesions. Current techniques , hardware  and outcomes are far below the idealistic solutions in bifurcation lesions.
  • Till that time ,  CABG would  remain the only choice for all , but for  a small fraction of isolated  left main disease where PCI may be possible.

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Drug eluting stents : A slap on the face of Evidence based cardiology . . .

Click the BMJ link or read below

 

venkat-bmj

It is often said science is sacred and unfortunately we forget ,  science is not a heavenly creation and it is the creation of scientist of varying grades of integrity fueled by the vested interest of medical industry . It has been a almost a daily affair , some of the devices and drugs are recalled or found to be unsafe on patients.

Now the big cat has come out .The Drug eluting stent has fallen from Hero to Zero in a short span of 5 years. It was projected to have zero percent restenosis in 2002 . And now we realize it is Zero percent truth.

What has started as anecdotal reports of late stent thrombosis has indeed become an epidemic in all DES patients. The five studies that has been published in the NEJM this month (March 2007) has convincingly proved how unsafe these stents are in most of the coronary population .

Millions of patients in whom this stent was implanted will carry an impending stent thrombosis and possibly an SCD . Who is to take care of them ?

The DES story is a clear cut case of getting premature approval for a dangerous form of treatment inside human coronary arteries.

It is amazing how the scientist’s eyes are shut by the illusion of knowledge and lure of wealth. How foolish they were to think drug which was administered via the stent will selectively prevent vascularisation and leave the normal endothelium intact . Now they realized , one should not suppress the endothelial growth around the stent and got the fundamental point wrong. Which was the key reason for the astonishing episodes of late stent thrombosis. When we play with biology of nature we have to be little more careful .God has created man and his heart for over a million years . One can not alter it by a 6 month follow up study of DES .

When ICDs were exposed last year , of similar disastrous outcome they were recalled and explanted . How are we going to unstent the millions of coronary arteries ?

Somewhere along the line the medical professionals have lost the battle against the Wall street and NASDAQ . Or how else we can explain repetition of similar events.

The wages for the modern technology , the patients have to pay a heavy price.

Let us all hope common man with common sense will reign supreme over the sixth sense of the uncommon man . . .

“Ignorance is better than illusion of knowledge”

Dr Venkatesan Sangareddi MD , Assistant Professor of cardiology , Madras medical college Chennai, India

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Anginal pain is a type of visceral pain.It is carried by type  C  unmylinated  nerve fibres.The perception of angina is a complex process.It is a combination of visceral and cutaneous referral pain.

How often is angina silent in diabetes mellitus ?

Presence of  diabetes per se does not make an angina silent. In fact,  if  one takes 100 patients with diabetes  , if angina occur in them , it is more often  , manifest than silent. So , only few of  the  diabetic patients who develop diabetic autonomic neuropathy fail to have angina.The exact incidence is not known.It could be around 20%.

If angina can be silent in diabteics , can they have anginal equivalents ?

This again is not answered in literature. Among the anginal equivalents , the most common is  dyspnea , which  can occur in diabetics.But now , we know dyspnea also needs thoracic nerve signals  from the intercostal muscle spindle and colgi organs.This can also be impaired in diabetics.

Can silent and mainfest episodes occur in a same  patient  ?

Yes.

Once silent does not mean always silent, and similarly once angina is felt it  does not mean he is going to feel the next episode as well !

This  strongly reminds us medical science  is  much a complex  subject and what we know is very little in pain perception.

How is silent ischmia different from silent angina ?

There is considerable  overlap  between  silent ischemia and silent angina

The questions to be answered are 

Which is silent  ?  Is it the angina or is it the ischemia or both ?

Silent ischemia can occur in any individual ,  this is also called as silent CAD . When  ischemia occurs  but  fails  to generate pain it is silent ischemia .Undiagnosed  CAD in asymptomatic individuals is also called silent ischemia or CAD.In this population  Exercise stress testing detects  CAD which was otherwise silent and masked.These patients may develop angina during EST.

During exercise stress testing many times patient has significant ST depression  more than 2mm but still chest pain may not occur.These episodes may either be silent ischemia or  ngina. Many times the EST is terminated before angina is manifest .( Chest pain is the last to occur in the chain of events following ischemia- Concept of ischemic cascade )

What are the other situations where angina can be silent ?

  • Pain perception  and threshold  level is  high ,  so patient indeed has anginal  signals but fails to feel it .
  • Patients on  antianginal medication , fail to feel the angina.
  • Chronic betablocker therapy can exactly mimic  autonomic neuropathy

Is it a blessing for the patient  to have painless episodes of angina ? 

When their  ischemic colleagues , suffer a lot with chest pain it is tempting to think these diabetic patients  are blessed!

Scientifically , this could be true in at least in  some  especially in a patients  who’s coronary anatomy is known  and devoid of any critical proximal lesions. For example a small PDA  lesion can produce  severe angina  , but may be silent  in diabetic and be comfortable .This lesion is  insignificant other wise * !

It should  also be recalled , pain relief has been an important goal for treatment  of CAD .In olden days,  thoracic sympathectomy was done for angina . In fact ,  even in  CABG  , one of the the  mechanisms  for  angina  relief  is attributed  to cardiac denervation.

Caution: Even a small  episode of ischemia can trigger an electrical event .But it is rare.

 How common is silent infarct (STEMI) in diabetic patients ?

In a simple questionnaire we asked the diabetic patients in our CCU how they felt their pain during MI.Most felt it normally as do other non diabetic .  Diabetes  does not make  all anginal episodes  silent. Severe episodes of ischemia may be painful while less severe episodes may be painless. Diabetic autonomic neuropathy  is a  least recognized and  poorly understood complication of diabetes.Diabetes , involves  the vasanervorum of the autonomic nerves.

 The other mechanisms postulated in diabetic neuropathy are

  • Reduction in neurotrophic growth factors.
  • deficiency of essential fatty acids .
  • Reduced endoneurial blood flow and
  • Nerve hypoxia .

Is diabetic autonomic neuropathy treatable ?

Very difficult problem indeed.Controlling diabetes may partially correct  the neural dysfunction.Many add on neuro vitamins and aminoacids are having a good market !

If you successfully treat diabetic autonomic neuropathy will my patient  start feeling the  hitherto silent episodes of angina ?

We don’t know.Logic would answer ” YES”

What is the ultimate effect of cardiac autonomic neuropathy.

Cardiac denervation.  The manifestations  are

  • Tachycardia, exercise intolerance
  • Orthostatic hypotension

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                                            The growth of medical science has been phenomenal .It is estimated , the quantum of break throughs  and development  in the  last  50 years  is   nearly equal  to  2000 years of evolution of our  knowledge  put together.  Along with this growth , came the  unavoidable misuse , and abuse of medical science. This  is mainly due to contamination of medicine with commerce . Federal drug authority (FDA) and it’s variants  were formed in all countries to monitor the proper usage of  these technologies for the benefit of mankind. It has an authority to ban a drug or device  , if it is found to bring more injury or side effects  than benefit !

But , unfortunately there is no legal authority to ban an  an  investigation  which is  potentially  or (really  harmful )

or  used  extensively without any valid purpose .

The list of such investigation is increasing in every speciality 

In  cardiology

  • Doing a Troponin assay in patients wuth classical STEMI
  • MDCT in general population
  • Pro BNP in all suspected cardiac  failure
  • Routine C reactive protein for CAD
  • Central venous catheters for all pateints with shock.

Is there a case for banning an investigation (Like banning a drug) for the benefit of  our patients ?

Looking superficially , it  may seem  ironical. But we realise many seemingly  innocuous investigations are responsible for uncontrolled misery for many patients.

This especially true in people who throng the wellness clinic (Also called master health check up)

A incidentally high C – reactive protein   can lead on to forearm blood flow assessment of endothelial dysfunction and carotid intimal plaque  that could  lead onto carotid stents ! and life long anticoagulation , and an  excess INR and sudden cerebral bleed and death !

This is one sample story  in one particular speciality

There is a definite case for banning ( Either total or partial)  some of the questionable investigations  which are done routinely !

Just because these investigation do not have any  physical , visible , adverse reactions like a drug , it should not be allowed to be abused  .The consequence of  false positive results of these investigations could be terrible and worse than the real disese itself !

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