Functional Evaluation of Coronary Bypass Surgery by Exercise Testing and Oxygen Consumption
The short-term effects of coronary bypass surgery were evaluated in 40 male anginal patients with 100% follow-up. Bicycle ergometry was performed pre- and postoperatively (three to eight months). The rate-pressure product (RPP) at angina and 1.0 mm ST segment change was recorded as well as oxygen consumption at the end of each three-minute work load.
All but three survivors (92%) reported symptomatic improvement. Mortality was 5% (2/40). Among survivors morbidity included 29% (11/38) with apparent intra- or perioperative infarctions (new Q waves).
In 20 postoperative patients (50%) neither angina nor ST changes could be elicited when exercised to fatigue. RPP at fatigue was increased an average of 48%. The highest measured oxygen consumption increased an average of 61%. Ten patients (25%) developed angina or ST changes at a higher RPP. O2 consumption in this group was unchanged (–3%). Five patients (12.5%) had no change or lower RPP at angina or ischemia. Their oxygen consumption was uniformly worse. Three patients (7.5%) were unable to exercise to preoperative RPP levels and could not be assessed. While the majority of revascularized patients are improved, the disparity between symptomatic and functional improvement reinforces the need for objective testing to determine the true effects of bypass surgery.
- © 1973 American Heart Association, Inc.