The diagnosis of restenosis.

Transluminal coronary angioplasty (TCA) ha; become a well established techn ique of coronary revascularisation. The medium-term results are however lim ited by the risk of restenosis. This restenosis occurs in the 6 months following angioplasty, above all bet ween the ist and 3rd month. The restenosis rate after balloon angioplasty i s about 40% and about 20% after implantation of a stent, at least in short lesions. Some factors related to the underlying disease (diabetes), the cli nical status and the date of TCA (unstable angina) or the type of lesion (c hronic occlusion, stenosis of venous grafts) are associated with a high ris k of restenosis. The occurrence of angina in the 6 months after TCA may be due to restenosis but also to incomplete revascularisation or the progressi on of non-significant lesions. This explains the low predictive value of an gina for the diagnosis of restenosis. In asymptomatic patients, the diagnosis depends on non-invasive tests. The positive and negative predictive values of exercise stress testing are low (about 50% and 75%, respectively), Nevertheless, stress testing remains use ful for assessing the functional capacity of patients, to confirm the absen ce of symptoms and to document silent ischaemia. The sensitivity of stress Thallium scintigraphy, associated or not with dipyridamole, is higher. Stre ss echocardiography, currently under evaluation, would seem to be as useful as Thallium scintigraphy for the diagnosis of restenosis.