Monday, July 20, 2009


Medicine is becoming more and more costly, especially in USA where a nights stay in a medical center could cost a few thousand USD. This has spun a near branch of medicine called minimally invasive surgery. Many of these surgery make use of the fact that videoscopes can be inserted through keyholes, thereby causing less trauma and so faster recovery and faster discharge. So we hear of laparoscopic cholecystectomy ( removal of gallbladder ), arthroscopic knee surgery ( operating on the knee joint through a videoscope ). Some even attempt laparoscopic worm removal, etc., etc. We also have a procedure called minimally invasive coronary bypass ( keyhole heart bypass ), which requires the leg veins ( the conduits used for the bypass ) to be harvested through a keyhole so that there is no need for a long leg incision. Cosmetically it looks better and recovery is faster. As we all know, the veins ( conduits for bypass ) is a very important part of the bypass. Yes, it is important to graft ( stitch ) the veins to the heart and the aorta. But if the conduit ( veins ) are not properly harvested, they can be damaged at the time of the harvesting ( through the videoscope ), and cause early blockage of the veins, thereby resulting in early reblockage of the bypass. For many years, many of us have suspected the minimally invasive coronary bypass does not work as well as the standard CABG ( coronary bypass surgery ), because of the higher bypass re-blockage rate following surgery. The initial studies done with follow-up over 6 months showed no difference between standard bypass using the heart lung machine and minimally invasive coronary bypass.
However, a sub-group analysis of the recent clinical trial, The PREVENT IV trial with longer followup shows this not to be so. The investigators from Duke University Durham ( a very wellknown cardiac hospital ) shows this not to be so. The investigators led by Dr Renato Lopes ( published in the July 15th issue of the New England J of Medicine ) found that veins after 18 months, 30% of the vein bypass have re-blocked.
It is not difficult to explain why. When I was in training, the very famous cardiac surgeon, the late Victor Chiang, use to tell us that probably the most important part of the coronary bypass procedure is harvesting the veins. He use to teach his fellows to harvest all the veins very gingerly and not damage any part of it. Veins do have many tributaries, and in harvesting, each of these tributaries must be meticulously tied off and handled with care so that no part is damaged. Otherwise, the damage part will result in blood clots forming on them once they are grafted, and this will result in blockage of the graft. Dr Chiang's coronary bypass use to be world re-known to last as long as the arterial grafts that some other surgeons use.
I once saw a video tape of the videoscopic harvesting of the veins. It was so rough with tugging and pulling to mobilise the veins. I knew that these kind of techniques goes against the basic understanding of medical science, and will surely fail.
The evidence is now provided by Dr Renato and colleagues. However, I am confident that with more training ( and minimally invasive surgery have a very long and steep learning curve ) the technique will evolve and get better.
So remember, less trauma does not necessarily mean better outcome. There is a rather steep learning curve and choosing the right surgeon is important.

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