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July 12, 2007
CABG
On the face of it, it makes sense to bypass a blocked artery. This is a common surgery in the US. 1998 figures indicate over a half million CABG's were performed annually, at a cost of $30 Billion. In the United States in 2004, the NCHS estimates that 427 000 of these procedures were performed on 249 000 patients.
Are they accomplishing what they purport? Almost definitely not. Part of the problem is that from the beginning, everyone knew they were only effective (statistically) for a limited subset of high-risk patients. But it makes so much sense that everyone thought they needed one.
A good review of the data is available several places. I am tempted to quote the 12 pages of an article by David K. Cundiff. But I won't. The gist is this. Even for the particular subset most benefited, the NNT is 20 for 5 and 10 year survival. That is a cost of $1 million for one patient more surviving at 5 and 10 years. And [uncertain-Cundiff claims 3%] operative mortality, and other harms (infection, heart attacks, disabilities).
Further, Cundiff argues that even the improved survival seems to be from some mechanism other than revascularization, based on discrepancies between the groups in the BARI trial. Even "the reduction in angina and increased exercise tolerance with CABG compared with medical treatment in high-risk subgroups may well have occurred because of an effect other than revascularization -- the placebo effect (ie, the patient's belief in the efficacy of the therapy), surgically induced infarction of ischemic tissue, denervation of the myocardium, increased motivation to reduce cardiac risk factors, and/or other influences."
Could it be that we have misled and been misled concerning the efficacy of CABG? Is it because we are so desperate to believe that medicine/surgery can cure?
| By Robert Maddox | 07:43 PM