I have a 56 year old patient in ESRD on hemodialysis with a left radial AV fistula . He was being planned for renal transplant and was discovered to have critical and diffuse CAD- so being taken up for CABG .
Plan so far :
1. avoid LIMA because of left AV fistula
2. avoid pump – use high pressures if CPB reqd – pulsatile ? – cool / drift temp ? – arrest heart vs on CPB beating heart ? heperkalemic cardioplegia ? custodial cardioplegia ?
3. hemo filter during surgery if required
4. Immediate preop and post op (as reqd) hemodialysis
5. Irradiated blood (in view of later immunosuppresants for renal tx) , leucocyte filter
6. nephrotoxic drugs – not really a problem as his kidneys are knocked out
I would appreciate any tips / additional fine points etc by my learned perfusion colleagues re;
1. Conduct of CPB in such cases
2. use of hemofilter – the nuts and bolts – we have a limited experience
3 . queries re cardioplegia
I spoke with our lead surgeon, Dr Springer, who does these sort of case all the time. He states that there is no need to avoid using the LIMA in spite of the left sided AVF. We don’t change our cardioplegia for these cases, but utilize ultra filtration on all of our cases. We use the Z-Buff technique to reduce the K+ in tandem with insulin (if necessary).
Z-Buffing is very simple. Drop a liter of NaCL and 50 MEQ NaHCO3, and ultrafiltrate the volume out- as well as usually an additional 500-1000 cc’s of volume from the patient. It is not unusual to use 3 liters of NACl and 150 MEQ of NaCL and having a net volume extraction of 4-5 liters. Mannitol in the prime is effective in terms of depleting the Pt sodium levels- which are in turn returned to normal levels as a result of the Z-buffing techniques. 12.5 to 25g of mannitol is our standard prime constituent.
CPB is conducted in the usual fashion- non pulsatile, and no adjustment to cardioplegia is necessary.
Thanks Frank and Dr Springer – will keep you posted re my case – I will avoid pedicled in situ LIMA as there is evidence showing steal phenomenon when performing post op hemodialysis via fistula . Will use RIMA and maybe free LIMA .
Recently I have been performing on-CPB empty beating heart CABG – no cardioplegia – and have been very happy with the results (I was till now doing 100% off pump for the last 15 years – and have given lectures / conducted workshops and published papers on the same ) – why I am shifting technique is another interesting story for another day !
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