Exercise tolerance five years after coronary bypass surgery in relation to clinical and angiographic findings.

Exercise on a bicycle ergometer was used to assess symptom-limited working capacity (Wsl) five years after coronary bypass surgery. Ninety-six patients were evaluated with a sitting bicycle test using 10 Watt increments of work load every minute from an initial load of 10 Watt. Ninety-three per cent had less symptoms than before surgery and 32% said they had no angina. Angina was provoked at exercise in 1/31 asymptomatic patients (3%) and in 46/65 (71%) of those with residual symptoms. The Wsl of 50-250 Watt (mean 143 Watt) in a asymptomatic patients was significant higher than 30-220 Watt (mean 105 Watt) performed by patients with residual angina. In 61 patients, exercise tests were performed before, one year and five years after the operation. Average Wsl was significantly higher after one year (127; 36 Watt) than before surgery (90; 23 Watt). but declined significantly until the five-year evaluation (113; 37 Watt). After one year 82% had a higher Wsl than prior to operation compared to 69% five years after surgery. Angiography five years after surgery revealed that 60/76 subjects (79%) had all grafts patent and 16/76 (21%) one or more grafts occluded. In spite of one or more grafts occluded. 2/16 patients (13%) were asymptomatic, whereas 25/60 (42%) with all grafts patent were free from symptoms. Average Wsl was significantly higher in patient with all grafts patent (130; 44 Watt) compared to patients with one or more grafts occluded (102; 33 Watt). It is concluded that although subjective improvement after coronary bypass surgery persisted in about 90% of the patients for five years, bicycle exercise tests show a significant decline of Wsl after the first year, but five years after surgery was still better than before the operation.