A picture is worth a 1000 words - why coronary surgery fails

Many patients who get chest pain ( angina) get a coronary angiogram done, which shows blocks in their arteries. The doctors explain that it's this block which is impairing blood supply to the heart muscle, as a result of which they get pain. They then propose bypass surgery ( or angioplasty, depending upon if you are talking to a cardiologist or a surgeon !) to "bypass " the block, and cure the pain. This is a very convincing argument, and how can anyone argue with such clear pictures or such logic ? Block = pain; treatment = bypass block.

Unfortunately, this argument has a major flaw. The angiogram only allows us to visualise the large arteries of the coronary circulation. However, the blood to the heart muscle is supplied through a dense network of much smaller blood vessels and capillaries which are too small to be seen on the angiogram. This means that the blocks in the large vessels seen on the angiogram meybe of no importance whatsoever in the individual patient. However, since we cannot see the small vessels ( even though these are much more important), we spend time, money and energy on bypassing the unimportant blocks - after all, if you have a hammer, you go around looking for nails ! This second image, which is a cast of the coronary circulation shows the important blood vessels which nourish the heart - and you can see that these are not "seen " at all on the angiogram !