[HSF] The fallacy of surgical research

Wed Aug 1 23:30:29 EDT 2007

Hello
very good discusion, what about of evidence based medicine it is always 
necesary in our clinical practice of cardiac surgery?, remember the 
relativity theory of Einstein, "all is relative", is relative the bad or 
good cardiac protection with one or another mixed??
thanks
edgar manrique

>From: prasannasimha <prasannasimha at gmail.com>
>Reply-To: OpenHeart-L at lists.hsforum.com
>To: OpenHeart-L at lists.hsforum.com
>Subject: Re: [HSF] The fallacy of surgical research
>Date: Thu, 02 Aug 2007 07:31:58 +0530
>
>Of course and yes the research is based on animal experimentation etc etc 
>but unfortunately we cannot excise our test human specimens to determine 
>wet versus dry weight and so on and so forth . We thus have to end up with 
>surrogate markers. Laughing it all off may be easy but then try setting a 
>true "EBM based RCT" which by itself has been questioned. Yes Eminence 
>based medicine  can be questioned but if you see most of surgical research 
>including your bread and butter the heart lung machine - one survivor of 6 
>patients of Gibbon would not muster as scientific and probably even 
>unethical yet you are using this everyday. Do not think that even the 
>physical sciences have "absolute proofs or RCT's etc" they simply don't if 
>you go about rigorously examining them. Nice in theory but difficult in 
>practice. Its always easy to be contrarian but unfortunately most 
>(practically all) of medical science is based on rejection of a null 
>hypothesis and not proving the test hypothesis.
>Prasanna
>Ani Anyanwu wrote:
>>The other issue the discussions on myocardial protection brings up is the 
>>fallacy of surgical research and the poor understanding of research method 
>>by surgeons.  This is what prompted the Lancet editor many years ago to 
>>describe surgical research as 'comic opera'. The reality is that few in 
>>academics or research takes us surgeons seriously. Look at the 
>>representation of surgeons in key research bodies, funding of surgical 
>>research by NIH or similar bodies, surgical influence in research groups, 
>>surgical publications in key journals, guidelines committees, involvement 
>>in key epidemiological efforts etc. The only Nobel prize received by a 
>>surgeon in the recent era wasn't even for surgical research. The problem 
>>is we as surgeons believe too much in our individual selves and individual 
>>methods that we become blinkered as to the requirements of the scientific 
>>method.
>>  Examples include
>>  - there is evidence that such and such an additive to cardioplegia is of 
>>benefit (this evidence comes from isolated animal hearts, animal 
>>experiments and at best clinical measures of surrogate markers - these do 
>>not mean the additive is benefit in the human, indeed it could be worse)
>>  - it has worked well in my cases so it is okay (but as Dr Salerno and 
>>Prasanna say the heart has great reserve - that nothing goes wrong does 
>>not mean all is okay)
>>  - i have had no deaths (the patient came to you alive; why is it an 
>>achievement that he remains alive after surgery? (unless the aim of 
>>surgery was to save life))
>>  - Kirklin and Buckberg or Cleveland clinic demonstrated...(i.e. eminence 
>>based medicine; but how many have ever read work of Kirklin or Buckberg? 
>>Do they stand up to the requirements of scientific proof? Indeed did 
>>either really show clinical benefit of the things we attribute to them? 
>>For example the 'seminal' Cleveland clinic NEJM paper purpurtedly showing 
>>benefit of IMA over SVG barely constitutes evidence of such)
>>  - There was no enzyme rise (has anyone cared to show any relationship 
>>between enzyme rise and any outcome of interest after surgery? Does the 
>>patient really care what his CK, troponin or coronary sinus lactate are? 
>>Why do we look at outcomes of no relevance to the patient?)
>>  - Ventricular fibrillation means bad protection ( but has anyone shown 
>>so scientifically? maybe fibrillation is intrinsic to some techniques and 
>>rare with others and is a reflection of the technique rather than the 
>>degree of protection; certainly a fibrillating heart in Salerno's beating 
>>heart technique has different implications to an Arch done by Martin on 
>>DHCA)
>>  - The patient was extubated the next day (and so what? Several times you 
>>go back to ask what happened to the patient 2 months later and you hear a 
>>different story. This outcome is of no relevance at all unless aim of 
>>surgery was to allow extubation in patient previously ventilator 
>>dependent)
>>  - My method of cold myocardial preservation works (but how do you know 
>>that that is what is working? As Salerno says if you don't know the 
>>myocardial temperature how do you know it is the hypothermia, and not some 
>>other factor, that is in play?)
>>  - Since I changed I use less inotropes (but you decide what you use- 
>>could you not be just biased towards the success of your change? Maybe you 
>>should compare two methos objectively)
>>  - Multiple defibrillation harms the heart and leads to bad outcome 
>>(maybe but could it be the condition requiring defibrillation that is 
>>resulting in the bad outcome rather than the shock?)
>>  - I have done it this way for 10 years and never had problems (how do 
>>you know? Have you actually measured the outcomes on all your patients? 
>>Kocher said the same about his thyroidectomies and was shocked when he 
>>recalled his patients and found the majority had myxedema)
>>  etc
>>The inability to critique within the scientific framework and a lack of 
>>understanding of, or refusal to apply the research method, is a major 
>>problem in surgery and is in part the reason why we are so diverse in 
>>opinion and yet so opinionated and firm in our belief that what we do is 
>>right (when yet examined there is often no evidence to support it). No 
>>internist or scientist or epidemiologist would approve a drug based on any 
>>of the criteria we list above yet we swear by what we do to the degree 
>>that we suggest alternative approaches are inferior.  Until we start 
>>thinking in a scientific and epidemiological manner, we as surgeons will 
>>remain the laughing stock of academic medicine.
>>  Ani
>>
>>
>>>Date: Thu, 2 Aug 2007 04:52:48 +1000> To: OpenHeart-L at lists.hsforum.com> 
>>>From: benjamin.bidstrup at bigpond.com> Subject: Re: [HSF] Inotropes, 
>>>ventricular fibrillation and myocardial protection> CC: > > What this 
>>>does is once again ask the question, how do we measure > myocardial 
>>>preservation?> > We can look at the highly sensitive markers such as 
>>>Troponin which > indicate some element of damage to components of the 
>>>myofibrils. and > so on. Echo - RWMA ECG and the list goes on.> We need 
>>>to look at use of inotropes, IABP, survival. Khuri published > on his 
>>>intramyocardiall pH device stating that poor preservation as > reflected 
>>>by pH changes resulted in altered long term survival.> > Much of the 
>>>cocktails' components have been determined by isolated > rat heart 
>>>experiments. They have translated well to the human, but it > is very 
>>>hard to measure total water content of an intact heart or > regional 
>>>blood flow distribution in a human model.> > Why is it that there is no 
>>>universal cocktail. Put 100 cardiac teams > in a room and you will have 
>>>120 different ways of preserving the > myocardium.> I review papers that 
>>>look at different methods of preservation and > they use markers such as 
>>>inotrope use to determine improvement. How > variable that is is a whole 
>>>new debate.> > > > > >Tomas,> >> > A fibrillating heart is a dying heart? 
>>>Is this an edict of some > >sort? I've seen plenty of hearts that 
>>>fibrillated during some part > >of their open heart operation only to 
>>>have a completely, and I mean > >completely, normal EF on remote echo. 
>>>Speaking in absolutes serves > >no purpose.> >> >> >> >Hal> >> >> 
>>> >-----Original Message-----> >From: Salerno, Tomas 
>>><TSalerno at med.miami.edu>> >To: OpenHeart-L at lists.hsforum.com> >Sent: Wed, 
>>>1 Aug 2007 11:19 am> >Subject: Re: [HSF] Inotropes, ventricular 
>>>fibrillation and > >myocardial protection> >> >> >> >> >A fibrillating 
>>>heart is. "Dying" heart.> >The brain does not have seizure during CPB; 
>>>neither should the heart > >fibrillate.> >Tomas> >> >----- Original 
>>>Message -----> >rom: openheart-l-bounces at lists.hsforum.com > 
>>> ><openheart-l-bounces at lists.hsforum.com>> >o: 
>>>OpenHeart-L at lists.hsforum.com <OpenHeart-L at lists.hsforum.com>> >ent: Wed 
>>>Aug 01 10:45:53 2007> >ubject: Re: [HSF] Inotropes,ventricular 
>>>fibrillation and myocardial > >rotection> >Ani,> >aving graduated from 
>>>voodoo homemade cocktails to blood and its> >ariants, you would easily be 
>>>able to see that the bad cardioplegia's> >id have a higher (more 
>>>accurately uniform) incidence of fibrillation> >hich came down with 
>>>better modifications of cardioplegia's. That does> >ake us wary and 
>>>anyway fibrillation is not something by any stretch> >ormal.Transient 
>>>defibrillation may appear innocuous but then it has> >een shown that such 
>>>hearts have indeed been improperly preserved (from> >orks of Buckberg and 
>>>Kirklin).Remember that sometimes speed etc etc may> >ompensate but this 
>>>may become an issue in longer case.> >rasanna> >ni Anyanwu wrote:> > I 
>>>still do not understand why we are alarmed about transient ventricular> 
>>> >ibrillation on reperfusion and why using drugs to suppress it will have 
>>>any> >mpact on outcome.> >> > Ani> >> >> >> > > >> Date: Wed, 1 Aug 2007 
>>>11:51:47 +0530> From: prasannasimha at gmail.com> To:> 
>>> >penHeart-L at lists.hsforum.com> Subject: Re: [HSF] Inotropes, 
>>>ventricular> >ibrillation and myocardial protection> CC: > > I am not 
>>>saying that the> >rocaine or lignocaine is still acting. What I> meant is 
>>>that since the> >ibrillation is occurring with the hotshot delivery> with 
>>>high local lignocaine> >hanging the drug class may be beneficial.> 
>>>Prasanna> > On 8/1/07, Ben Bidstrup> >benjamin.bidstrup at bigpond.com> 
>>>wrote:> >> > I beg respectfully to differ. The> >idocaine (a fast Na 
>>>channel> > blocker) is all but gone after a short while in> >he 
>>>cardioplegia> > scenario. Getting a suitable level back into the > 
>>> >circulation> >nd thus> > the heart at release of the clamp is what is > 
>>> >needed.> >> > Perhaps a> >andomised study is in the offing.> >> > > 
>>> >http://circ.ahajournals.org/cgi/content/abstract/79/5/1106>> >> > This 
>>>reference relates to defib energy levels but i think you will> > see> 
>>> >here I am coming from.> >> > At James Cook, I was involved in the 
>>>development> >f a non> > depolarising cardioplegia solution, which is 
>>>slowly > >working its way>> > up the development path. The main 
>>>components are lidocaine and> > adenosine.>> >> >> >> >> > >Ben,> > >I 
>>>use Amiadorone in the pump for all emazes > >>(and postop)> >nd> > 
>>> >Amiadorone in the pump for all aortic valves. Since the St Thomas> >> 
>>> >Cardioplegia (which we mix in blood) already has procaine > >adding> > 
>>> >Lignocaine> >ould be redundant.(Incidentally Amiadorone is very cheap> 
>>> > >in India !!)> >> >Prasanna> > >Ben Bidstrup wrote:> > >>Why the 
>>>amiodarone. Surely with some> >erfusion, the electrolyte> > >>imbalances 
>>>within the myocardium would correct> >nd SR ensue. If> > >>anything use 
>>>lidocaine. Less toxic and cheaper, not a> >egative> > >>inotrope. It is 
>>>what Yacoub taught me many years ago, and I have>> > >>used it to good 
>>>effect (infrequently I might > >add).> > >>> > >>>Tohru,> > >>>> > did an 
>>>AVR on an 87 yo man as a 2nd case just a couple of> > >>>hours ago.> 
>>> >gain, no LV vent, only a sump. While closing the> > >>>aortotomy, I 
>>>began the>> > >>>continuous warm retrograde blood. The heart began 
>>>fibrillating> > >>>after> > couple of> > >>>minutes. I gave amio and then 
>>>cardioverted. The > >heart had a> >> >>>slow junctional> > >>>rhythm 
>>>until the clamp was released. A sinus rhythm> >eveloped shortly> > 
>>> >>>afterwards. He came off with no inotropes. It's much> >asier on> > 
>>> >>>the heart and> > >>>your nerves to cardiovert a > >clamped, flaccid> 
>>> >eart rather than> > >>>trying to do it> > >>>after the clamp has been> 
>>> >eleased.> > >>> I look forward to your visit at the STS. As I said 
>>>before,> >'ll> > try to> > >>>have a couple of interesting cases for you 
>>>and other> >nterested> > >>>members of HSF> > >>>to watch and criticize 
>>>to your heart's> >ontent.> > >>>> > >>>Hal> > >>>> > >>>> > >>>> > 
>>> >>>**************************************> >et a sneak peek of the> > 
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>>>Daniel J Boorstin> >> > Ben Bidstrup FRACS FRCSEd FEBCTS> > Consultant> 
>>> >ardiothoracic Surgeon> > 
>>>_______________________________________________> >> >penHeart-L mailing 
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