A single story

So there are many sites: the clinic (which can be divided between the patients’ complaints and the physical examination); the pathology laboratory; the radiology department; duplex; and the operating theatre. Mol describes at least five locations at which lower-limb atherosclerosis appears, and she could find more. She writes, for instance, of ‘walking therapy’, an alternative, non-invasive treatment for intermittent claudication.43 She also visits the haematology department, where there is research into the formation of the plaque which leads to stenosis and lumen loss. But let us stop at this point. We have a large number of locations and each is its own method assemblage, its own set of health-related crafts and practices. And, if we follow the logic proposed by Latour and Woolgar, then we also need to add that each of these method assemblages is producing its own version of atherosclerosis: that there are multiple atheroscleroses. But what should we make of this startling conclusion? Are we happy to see the erosion of reality as singular?

If you ask the professionals, they usually talk about a single object, or about a set of objects and processes that fit together to produce a single reality. I touched on this above. Thus they say that long-term changes in the blood, perhaps partly due to diet and insufficient exercise, may lead to a slow build- up of atheromatous plaque and thickening of the intima. At first this has little effect, but at a certain point lumen loss becomes so great that blood flow is reduced. Then the patient experiences pain on walking – intermittent claudication – and he or she is likely to go to the doctor’s surgery. When this happens other symptoms become visible – for instance the relative absence of pulsations, and the discovery of temperature differences between the legs. With further investigation additional symptoms become visible, and their locali- sation becomes possible. Duplex may be used to locate partial stenosis by measuring increases in the maximum speed of blood flow, or angiography to pinpoint partial or total stenosis.

So much for the story of origins and diagnosis. But what of treatment? In milder cases this may take the form of walking therapy.44Otherwise the alter- native is surgery. I have described one version of this above. Endarterectomy

is an operation in which the offending plaque is physically stripped from the inside of the artery. But there are at least two further possibilities. In an operation called percutaneous transluminal angioplasty (PTA) the stenotic vessel is inflated from the inside using a device like a tiny inflatable balloon on the end of a tube which has been inserted into the vessel. The object in PTA is to push aside the plaque and increase the diameter of the lumen. A third possibility is to create a bypass round the sclerosis. And a fourth – necessary if the blood flow is so poor that there is risk (or the reality) of gangrene – is amputation. And it is only with this fourth form of intervention that the practices of the pathology laboratory become possible: cutting and preparing thin cross-sections of vessels with stenosis, and observing the growth of the intima and the loss of lumen under the microscope.

Дата добавления: 2015-11-14