An MD&DI February 1999 Column
Does a simplified procedure for coronary-bypass surgery signal a fork in the road for cardiac-care technology?
We tend to think of progress in medical technology as resembling the river that is the answer to an old riddle: something that follows the same course, never gets tired, and never reverses itself. Advances generally move in the direction of greater complexity: more-involved science, more-sophisticated instrumentation, increasingly difficult and intricate techniquewhat J. Robert Oppenheimer called the "vast, complex, ever growing, ever changing, ever more specialized and expert technological world."
Occasionally, however, progress arrives in the form of a radical simplification, as in the current revolution in coronary-bypass surgery. Although the heart-lung machine is among the marvels of medical engineering, it's long been acknowledged that the device is responsible for troublesome side effects in patients. The machine damages cellular blood components, increasing the potential for both infection and bleeding; risks inducing strokes by generating minute clots and air bubbles during oxygenation; and often imparts a profound systemic shock referred to by doctors as "pump head," with manifestations ranging from cognitive deficits to clinical depression. These are serious but heretofore unavoidable complications: after all, it is the machine that keeps the patient alive while the heart is stilled and the diseased arteries bypassed.
Now there is another option, one that takes the patient off the pump altogether: the beating-heart bypass. Steadily gaining momentum over the past two or three years, this procedure, long considered impossible, has arisen thanks to the development of a specially designed set of instruments. Replacing the heart-lung machinewith its draining and infusion lines, cardiotomy reservoirs, arterial filters, membrane oxygenators, precision pressure-control mechanisms, and fail-safe power suppliesare forks and spoons!
Individual surgeons, some of them tinkering at garage or basement workbenches, devised their own versions of a simple tool used to press down on the still-beating heart and stabilize the operative site so that bypass grafts can be sewn into place. One model looked like a two-tined dinner fork; another, a soup spoon with a small window cut in the bowl. Even though some of these devices have since been commercialized and refined (a recent variant uses suction cups to grip and hold the heart surface), the level of the "technology" can be compared to what emerges from an average high-school metal shop.
Follow-up studies of patients who underwent beating-heart bypass have shown the off-pump procedure to be as effective as traditional heart-lung surgery, with significantly fewer complications. It is also less expensive: the operation itself is some 40% cheaper, with a 60% overall reduction in hospital stays, fewer tests, and less time spent in intensive care. Apart from perfusionists and the manufacturers of heart-lung machines, everyonedoctors, patients, insurersappears to have benefited from making things simple.
Will the next breakthrough feature a similar forks-and-spoons retreat from the ramparts of technological complexity? Should those searching for a small-diameter vascular prosthesis take a look at, say, coffee stirrers? The answer, of course, is that getting things to seem easy is hard, and simplification subtle. In this story, the real technological advance is the conceptual audacity of leading-edge scientific practitioners, whose hard-won skill and experience enabled them to rethink some of the bedrock principles of their discipline.
To appreciate what's really involved, invite a cardiac surgeon for dinner. Just be sure to count the silverware.