[HSF] The fallacy of surgical research

Thu Aug 2 05:03:41 EDT 2007

Prasanna

The often calls for RCTs or the belief that RCTs are what is meant when one asks for 'scientific proof' is a misconception. The majority of questions in surgery do not require an RCT to proof the answer; the RCT is appropriate only in few circumstances in Surgery. Depending on the question, different research techniques are required to find the answer. Like in your example of CPB all one needs is a case report or case series for at the time there was no alternative. Same applies for interventions like insulin or penicillin or blood transfusion. An RCT is not required in this setting. Similarly to discover whether your ligation method is effective in obliterating the LAA we do not need an RCT but a carefully conducted cohort study. 

Surrogate markers are of little value in clinical research except where there is definite proof of a link with outcome (for example creatinine clearance as a surrogate for renal failure). However, for the cardioplegic solutions the fact that one has less CK release than another does not mean it is superior (if so does it then mean PCI is more protective than OPCAB which is more protective than ONCAB?). Surrogate markers are the requirement for animal experimentation and initial clinical work but to show efficacy, one needs a clinical outcome that matters. Hans Troidl has written excellently on the subject of choosing surgical endpoints and more often than not, the endpoints we use are the wrong one, such as the often use of 'patint was extubated next morning' as a surrogate for success in a complex case presented to the forum. 

As regards day to day practice, as Don says, little of what we do is based on evidence. There is nothing wrong with basing what we do on anecdote or what we were taught but that is no proof that what we are doing is effective or correct. On this forum however we often portray things as fact or gospel when we have no evidence, and younger surgeons like myself may be deceived into taking some of these surgical myths as fact. For example two weeks ago I challenged anyone to bring forth evidence that obliterating the LAA reduces strokes and no one could provide any except 'I ligate or excise them all and have seen no strokes'. Or there was some discussion as to why a 7/0 needle or suture is superior to a 8/0 needle or suture - again presented as fact but backed by no data or evidence or even biological logic. I wondered to myself - so why not a 9/0 suture then? 

Of course we can have our opinions but we should not present them as scientific fact. If you actually go to measure what you do, you will be surprised how far your perceptions are from reality.  A last anecdote, as a trainee I once had charted the mortality rate for 5 surgeons - there were no identifiers attached. One surgeon looked at it and said it cant be right that I must have missed one or two of his deaths (he was thought his mortality was slightly worse than the 1% credited to Surgeon A) - unknown to him he was not the surgeon A with the best results but surgeon E with a 7% mortality. 

Ani

> Date: Thu, 2 Aug 2007 07:31:58 +0530> From: prasannasimha at gmail.com> To: OpenHeart-L at lists.hsforum.com> Subject: Re: [HSF] The fallacy of surgical research> CC: > > 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> > >>>all-new AOL > >at> > >>>http://discover.aol.com/memed/aolcom30tour>> > >>>_______________________________________________> > >>>OpenHeart-L mailing> >ist> > >>>> > >>>Send postings to:> > >>> > >OpenHeart-L at lists.hsforum.com> > >>>>> > >>>To UNSUBSCRIBE, to CHANGE email address, or to view archives:> >> >>>http://mmp.cjp.com/mailman/listinfo/openheart-l> > >>>> > >>>All messages> >ransmitted by the OpenHeart-L are subject to the policies> > and> >> >>>disclaimers posted at:> > >>>http://www.hsforum.com/listdisclaim> >> >>>-----------------------------------------> > >>> > >>> > >> >> >_______________________________________________> > >OpenHeart-L > >mailing list> >> >> > >Send postings to:> > >OpenHeart-L at lists.hsforum.com> > >> > >To> >NSUBSCRIBE, to CHANGE email address, or to view archives:> >> >http://mmp.cjp.com/mailman/listinfo/openheart-l> > >> > >All messages> >ransmitted by the OpenHeart-L are subject to the> > >policies and disclaimers> >osted > >at:> > >http://www.hsforum.com/listdisclaim> > >----------------------------------------->> >> >> > --> >> >> > Two things are infinite; the universe and human stupidity;> >nd I am> > not sure about the universe.> > Albert Einstein> >> > The greatest> >bstacle to discovery is not ignorance --- it is the> > illusion of knowledge.>> > Daniel J Boorstin> >> > Ben Bidstrup FRACS FRCSEd FEBCTS> > Consultant> >ardiothoracic Surgeon> > _______________________________________________> >> >penHeart-L mailing list> >> > Send postings to:> > > >OpenHeart-L at lists.hsforum.com>> >> > To UNSUBSCRIBE, to CHANGE email address, or to view archives:> >> >ttp://mmp.cjp.com/mailman/listinfo/openheart-l> >> > All messages transmitted> >y the OpenHeart-L are subject to the policies> > and> > disclaimers > >posted at:>> > http://www.hsforum.com/listdisclaim> > > >----------------------------------------->> >> > > > -- > Prasanna Simha M> > >>_______________________________________________>> >penHeart-L mailing list> > Send postings to:> OpenHeart-L at lists.hsforum.com> >> >o UNSUBSCRIBE, to CHANGE email address, or to view archives:>> >ttp://mmp.cjp.com/mailman/listinfo/openheart-l> > All messages transmitted by> >he OpenHeart-L are subject to the policies and > disclaimers posted at:>> >ttp://www.hsforum.com/listdisclaim> -----------------------------------------> >> > > _________________________________________________________________> > 100's of Music vouchers to be won with MSN Music> > > >https://www.musicmashup.co.uk/index.html_______________________________________________> > OpenHeart-L mailing list> >> > Send postings to:> > OpenHeart-L at lists.hsforum.com> >> > To UNSUBSCRIBE, to CHANGE email address, or to view archives:> > http://mmp.cjp.com/mailman/listinfo/openheart-l> >> > All messages transmitted by the OpenHeart-L are subject to the policies and> > disclaimers posted at:> > http://www.hsforum.com/listdisclaim> > -----------------------------------------> >> >> > > >_______________________________________________> >penHeart-L mailing list> >Send postings to:> >OpenHeart-L at lists.hsforum.com> >To UNSUBSCRIBE, to CHANGE email address, or to view archives:> >ttp://mmp.cjp.com/mailman/listinfo/openheart-l> >All messages transmitted by the OpenHeart-L are subject to the policies and> >isclaimers posted at:> >ttp://www.hsforum.com/listdisclaim> >----------------------------------------> >> >> >> >_______________________________________________> >penHeart-L mailing list> >Send postings to:> >OpenHeart-L at lists.hsforum.com> >To UNSUBSCRIBE, to CHANGE email address, or to view archives:> >ttp://mmp.cjp.com/mailman/listinfo/openheart-l> >All messages transmitted by the OpenHeart-L are subject to the policies and> >isclaimers posted at:> >ttp://www.hsforum.com/listdisclaim> >----------------------------------------> >> >> >________________________________________________________________________> >AOL now offers free email to everyone. Find out more about what's > >free from AOL at AOL.com.> >_______________________________________________> >OpenHeart-L mailing list> >> >Send postings to:> > OpenHeart-L at lists.hsforum.com> >> >To UNSUBSCRIBE, to CHANGE email address, or to view archives:> >http://mmp.cjp.com/mailman/listinfo/openheart-l> >> >All messages transmitted by the OpenHeart-L are subject to the policies and> >disclaimers posted at:> >http://www.hsforum.com/listdisclaim> >-----------------------------------------> > > -- > Ben Bidstrup FRACS FRCSEd FEBCTS> Consultant Cardiothoracic Surgeon> > Two things are infinite; the universe and human stupidity; and I am > not sure about the universe.> Albert Einstein> > The greatest obstacle to discovery is not ignorance --- it is the > illusion of knowledge.> Daniel J Boorstin> > > _______________________________________________> OpenHeart-L mailing list> > Send postings to:> OpenHeart-L at lists.hsforum.com> > To UNSUBSCRIBE, to CHANGE email address, or to view archives:> http://mmp.cjp.com/mailman/listinfo/openheart-l> > All messages transmitted by the OpenHeart-L are subject to the policies and > disclaimers posted at:> http://www.hsforum.com/listdisclaim> -----------------------------------------> >> > > _________________________________________________________________> > The next generation of MSN Hotmail has arrived - Windows Live Hotmail> > http://www.newhotmail.co.uk_______________________________________________> > OpenHeart-L mailing list> >> > Send postings to:> > OpenHeart-L at lists.hsforum.com> >> > To UNSUBSCRIBE, to CHANGE email address, or to view archives:> > http://mmp.cjp.com/mailman/listinfo/openheart-l> >> > All messages transmitted by the OpenHeart-L are subject to the policies and > > disclaimers posted at:> > http://www.hsforum.com/listdisclaim> > -----------------------------------------> >> >> > > > _______________________________________________> OpenHeart-L mailing list> > Send postings to:> OpenHeart-L at lists.hsforum.com> > To UNSUBSCRIBE, to CHANGE email address, or to view archives:> http://mmp.cjp.com/mailman/listinfo/openheart-l> > All messages transmitted by the OpenHeart-L are subject to the policies and > disclaimers posted at:> http://www.hsforum.com/listdisclaim> -----------------------------------------
_________________________________________________________________
Celeb spotting – Play CelebMashup and win cool prizes
https://www.celebmashup.com/index2.html