Of 46 consecutive patients who underwent percutaneous transluminal coronary angioplasty (PTCA) from April 1980 to August 1982 and who had a satisfactory angiographic result six months later, one died of cancer and 41 had a detailed evaluation with exercise single-photon emission computed tomography (SPECT, 40 patients) or repeat coronary angiography (one patient), 48-78 months after the procedure. During follow-up, two patients had recurrent angina due to progression of coronary artery disease requiring a second PTCA procedure of another coronary artery; one of them later had a limited myocardial infarction in an area supplied by the vessel initially dilated. At follow-up, only one patient had definite angina. All but one patient had a negative exercise test. Myocardial perfusion during exercise in the PTCA-related area, assessed by SPECT, was normal in 90% of the patients and showed a limited defect due to reversible ischaemia in the remaining four (10%). It is concluded that patients with a less than 50% stenosis six months after PTCA show sustained improvement in their functional status and myocardial perfusion, four to six years after the procedure suggesting continued patency of the coronary artery.