Azathioprine-induced shock.

sufflation in peripheral vascular disease. The gas, from 100 to 400 ml, is injected directly via an arterial catheter, the site depending on the angiographically demonstrated arterial supply to the limb. I have reserved the method mainly for those who are not suitable for angioplasty and in whom surgery is not contemplated. Twenty-one such patients, with generally severe and widespread disease, have been treated. Eight had rest ischaemia with threatened limb loss; objective evidence of reversal of ischaemia and complete symptomatic relief were obtained in five. In a follow-up period of up to seven months there were two recurrences, at three months and one month respectively, the latter patient being relieved by repeat insufflation. Three of the eight patients had no significant benefit. There were 13 patients with intermittent claudication-five with complete symptomatic relief, five with partial improvement , and three with no effect in a follow-up period of up to six months. The mode of action is unknown. In physiological studies in which small amounts of various gases were injected in the brachial artery of volunteers' temporary vasodilatation was found, without satisfactory explanation. In the cases reported here, the vasodilatation appears to be longer lasting, presumably at least sufficient to allow collaterals to develop. Alternatively, there may be a change in tissue metaoolism. These aspects are being investigated and will be subsequently reported. I appreciate that the method as yet has little scientific basis, and that in the group with claudication there is no objective evidence of benefit. However, until more definitive information can be provided, it is suggested that the method is at least worth trying in the category of patients described, for whom no reconstructive procedure, either by surgery or by percutaneous angioplasty, can be offered. Apart from the fact that it involves arterial catheterisation, the method appears to be perfectly safe. Minor discomfort in the limb may occur, with patchy mottling of the skin; but these are only transient effects. It is generally appropriate for the radiologist to carry out the procedure, as catheterisation of the most appropriate vessel (depending on the disease distribution) ensures optimum delivery. It can be performed at the time of the diagnostic angiogram if criteria for its use have previously been agreed locally. SIR,-We read with interest the report of Dr T Cunningham and others (26 September, p 823) about azathioprine-induced hypo-tension in two patients with rheumatoid arthritis who both had …