Angiographic findings of silent ischaemia following aortocoronary bypass surgery

Silent ischaemia, defined as ST-depression > or = 1 mm without chest pain, was found on exercise testing in 22 (10.7%) of 206 patients who underwent aortocoronary bypass surgery in the period from March 1983 to November 1985. Exercise testing was performed 4.9 (range 3.6-6.7) years after operation on an electrically braked bicycle. Sixteen of the 22 patients were free from chest pain, while the remaining six had slight to moderate angina pectoris on exercise. Coronary angiography was performed in 21 patients with silent ischaemia; one of the 22 patients died before this investigation. Some 13 patients had one or more occluded grafts, one a new stenosis in a native vessel and five incomplete myocardial revascularization. For the remaining two patients, no aetiology for the ischaemia was found, and revascularization appeared to be complete. Before surgery, 13 patients had three-vessel disease, six two-vessel disease and three one-vessel disease. At follow-up, two patients had three-vessel disease, ten two-vessel disease and seven one-vessel disease. The value of identifying patients with silent ischaemia after aortocoronary bypass surgery with regard to life expectancy and quality is controversial. Subsets of patients, namely, those with main-stem stenosis and three-vessel disease, may benefit from secondary operation. Identification of these patients may therefore be of clinical importance.