Anaerobic threshold and maximal oxygen uptake in patients with coronary artery disease and stable angina before and after percutaneous transluminal coronary angioplasty

In this study, we investigated the effect of percutaneous transluminal coronary angioplasty (PTCA) on functional exercise capacity, oxygen uptake at anaerobic threshold (VO2AT) and maximal oxygen uptake (VO2max) in patients with coronary artery disease (CAD). Twenty-five patients with CAD and stable angina pectoris underwent spiroergometry before and after PTCA. All patients had reduced functional capacity with Weber class B in 5, class C in 16 and class D in 4 patients with mean VO2AT of 9.4 ± 1.5 ml·kg–1·min–1 and mean VO2max of 13.3 ± 3.3 ml· kg–1·min–1. After PTCA, VO2max (15.8 ± 3.1 ml·kg–1· min–1) increased significantly (p < 0.001) compared to before PTCA. Subgroup analysis revealed that patients with low functional capacity before PTCA (VO2max –1· min–1) had the most benefit from PTCA with an increase in VO2AT from 8.7 ± 1.0 to 9.6 ± 1.4 ml·kg–1· min–1 (p < 0.05) and of VO2max from 11.3 ± 2.2to 14.8 ± 3.5 ml·kg–1·min–1 (p < 0.001) whereas in patients with VO2max >15 ml·kg–1·min–1, VO2AT (p = 0.9) and VO2max (p = 0.2) did not improve significantly. In conclusion, there is reduced functional capacity and VO2max which improved after PTCA in CAD patients. In patients with low VO2max before PTCA, functional capacity, VO2AT and VO2max significantly improved after PTCA, suggesting reversible myocardial impairment induced by intermittent myocardial ischemia. Patients with higher VO2max had no significant benefit from PTCA with respect to functional capacity, VO2max and VO2AT.