[HSF] how others will see us

Ben Bidstrup benjamin.bidstrup at bigpond.com
Mon Dec 4 08:06:47 EST 2006 

It is worth looking at Rob Poston's work on local ischaemia in OPCAB. 
See Innovations, JTCVS and Annals over the last few years.

>My major change in practice of coronary artery surgery has been 
>abandoning the heart lung machine for these operations, and making 
>sure that all constructed grafts, especially the LIMA-LAD is patent. 
>The only way to determine that, is by using quality control of all 
>anastomoses via one of the technologies available, such as flowmetry 
>or SPY techniques.
>
>By doing this, the incidence of EKG changes, MIs, return to OR 
>urgent due to ischemic changes, and others have practically 
>disappeared. I have trouble understanding how surgeons can perform 
>coronary artery surgery, with the need of loops, and yet do not 
>determine the quality of their work before and after protamine 
>administration, regardless whether this operations is done on or off 
>pump
>
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>Tomas
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>Tea,
>Very interesting  and plausible hypothesis regarding the reason for a
>lower MI incidence  for opcab!  There is little doubt that grafting
>tiny arteries is not beneficial except when that is all on offer.
>I don't know the incidence of routine shunting by dedicated opcabers
>but my MI incidence almost disappeared when I became a shunter.
>Perhaps if the on pumpers had a fat tube in the artery during
>anastomosi they would also find it hard to muck them up.
>Don.
>
>PS We received a call from a country hospital about a problem with a
>post-op cabg and the young doctor made the comment that It must have
>been done on pump because the patient had some cognitive decline. He
>was correct but the pity of it was that he was not a cardiologist.
>
>On 02/12/2006, at 5:26 PM, Tea Acuff wrote:
>
>>  As mentioned earlier in a thread about bias, evidence and aprotonin
>>  I have thoughts
>>  in referrence to http://stroke.ahajournals.org/cgi/content/
>>  37/11/2759 (In Stroke, 2006, "Off-Pump Surgery is associated with
>>  reduced occurence of stroke and other mordidity as compared to
>>  traditional coronary artery bypass grafting..." by Sedrekyan,
>>  Wu, ...Treasure)
>>  I don't read much of our literature, but am occasionally shown
>>  articles by those trying to interact with us and learn a lot. I
>>  found this an interesting perspective for those that seek to know
>>  us. In general I believe the findings to agree with my past decade
>>  of beating heart experience. (I think "off pump " is a simplistic,
>>  yet commonly discussed, benchmark for patients even if I do that as
>>  my standard.) I try to do only what is required. I, perhaps like
>>  the authors (is that why it is in "Stroke"), have stoppped trying
>>  to change surgeon's minds, although there may be reason to
>>  reexplore these issues. The discussion does point out the fact that
>>  the RCTs tend (as do more so the cardiology papers) to pick the
>>  "better" patients of which I think there is general agrement will
>>  have less benefit with a particular technique, but let's just deal
>>  with the findings.
>>  To wit:
>>  1) 255 abstracts were narrowed to 41 RCTs by two authors for a meta
>>  analysis of 3996 patients, not all endpoints were so represented as
>>  patients available for mortality were 3996 but patients for
>>  reintervention were only 1660
>>  2) significant differences favoring off pump were stroke 0.6% vs
>>  1.6% (p=.03), afib, 16.9% vs 24.8% (p<.001), wound infection  3.8%
>>  vs 7.7% (p<.001), MI 2.6% vs 3.4% (p=.26) renal failure 1% vs 2%(p=.
>>  26)
>>  3)favoring on pump: reintervention (9 trials only) 2.4% vs 1.2% (p=.
>>  08) cross over 7.9% vs 1.6% (duh!) (p=.08)
>>  4) neutral: mortality 1.6% vs 1.6% (p=.89)
>>  5) there were less grafts per patient in the off pump (-.26) but
>>  this varied inversely by study size of the number of patients per
>>  group with the "large" groups >50 (-.15) and small <25 (-.61). also
>>  studies with much higher on pump mortality (heterogeneity) than the
>>  norm were excluded.
>>   Interesting the authors also did elsewhere a meta analysis of
>>  aprotonin as statistical analysis appears to be an interest of theirs.
>  >
>>  My reflections:
>>  This is a (very) good risk group: mortality = 1.6%
>>  Surgeons are the least able to be objective about the data, and
>>  with good reason. If it takes 10 or more years to be good at
>>  something and you plan to do surgery anyway, it is stupid to change
>>  unless you think it is worth 10 more years of your life (or 5 if
>>  you a are a quick learner). It is not like changing types of stents
>>  that can be learned in a couple of weeks or even 50 cases. I
>>  personally think off pump skills take >500 cases to be similar to
>>  on pump (assuming that you have done 500 on).
>>  If the main reason more surgeons don't adopt off pump techniques is
>>  for concern of poor anastomoses, why do on pump techniques have
>>  more MI's?
>>  How many surgeons would prospectively trade 1% MI intraop for 1%
>>  reintervention postop? (I did not note that angina was LESS common
>>  in the postop off than on pump patient by the away which may be a
>>  futher bias...the "we did all we could"...)
>>  One of the keys to understanding this data is to think about what I
>>  claim EBM (evidence based medicine) is about. It is the study of
>>  the behavior of doctors to therapy as much as the patients response
>>  to our behavior.
>>  Here is how I logically think (I may be completely wrong, but it is
>>  my logic) about how off pump can have less MI, equal (? if we use
>>  these numbers as real world) mortality, and more reintervention.
>>  Surgeons over time become comfortable with their ability to do
>>  "necessary" anatomoses. All things being equal, which only is
>>  imagined to happen in a study not the real world, it is easier to
>>  do tinier and more diseased vessels with the heart still (intra
>>  surgeon not inter surgeon). More intra surgeon MI's come from
>>  stupid choices than stupid technique. (It may well be that surgeons
>>  with bad technique have more MI's , but this will not show up in
>>  randomization.) Just because you can sew it does not mean you
>>  should sew it. That is, surgeons adjust to their techniques ( if
>>  they have any brains at all) to their comfort which is in no
>>  (necessary) way similar to the needs of the patient. OFF and ON
>>  pump techniques are like bulls in a china shop. Just beacuse one is
>>  smaller and can go
>>   down a smaller isle doesn't mean it will do less damage
>>  automatically.
>>  Reasons for less stroke are both simple and impossibly complex.
>>  Reasons for less afib are so far and remain largely the newest
>>  conjecture.
>>  Ultimately the reasons for less morbidity of any kind is that IF
>>  you can accomplish what you need, less is always a better technique
>>  than more.
>>   If you can't and didn't (do what was needed), you may have to go
>>  back earlier  (reintervention) than you thought which is a
>>  judgement call.
>>  If we don't stop reading papers for statistics and think about what
>>  they mean, we (and our patients) are dead in the water.
>>
>>  Tea
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-- 
Ben Bidstrup FRACS FRCSEd FEBCTS
Consultant Cardiothoracic Surgeon

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