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 (VO(2 AT)) and maximal oxygen uptake (VO(2 max)) 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 VO(2 AT) of 9.4 +/- 1.5 ml.kg(-1).min(-1) and mean VO(2 max) of 13.3 +/- 3.3 ml. kg(-1).min(-1). After PTCA, VO(2 max) (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 (VO(2 max) <15 ml x kg(-1) x min(-1)) had the most benefit from PTCA with an increase in VO(2 AT) from 8.7 +/- 1.0 to 9.6 +/- 1.4 ml x kg(-1) x min(-1) (p < 0.05) and of VO(2 max) from 11.3 +/- 2.2 to 14.8 +/- 3.5 ml x kg(-1) x min(-1) (p < 0.001) whereas in patients with VO(2 max) >15 ml x kg(-1) x min(-1), VO(2 AT) (p = 0.9) and VO(2 max) (p = 0.2) did not improve significantly. In conclusion, there is reduced functional capacity and VO(2 max) which improved after PTCA in CAD patients. In patients with low VO(2 max) before PTCA, functional capacity, VO(2 AT) and VO(2 max) significantly improved after PTCA, suggesting reversible myocardial impairment induced by intermittent myocardial ischemia. Patients with higher VO(2 max) had no significant benefit from PTCA with respect to functional capacity, VO(2 max) and VO(2 AT).