Study objectives: Although percutaneous transluminal
coronary angioplasty (PTCA) is known to have beneficial effects on
exercise capacity, its effects on the cardiovascular response during
the onset of exercise have not been clarified. The present study was
undertaken to determine the effects of PTCA on the kinetics of oxygen
uptake (V̇o2) during constant-work-rate
exercise in patients with coronary artery disease, as well as on their
indexes of maximal work capacity.
patients with coronary artery disease who received successful PTCAs
performed a 50-W constant-work-rate exercise test for 6 min and a
symptom-limited incremental exercise test both before and 4 months
after the PTCA procedure. V̇o2 was
calculated from breath-by-breath analysis of respired gases. The time
constant of V̇o2 kinetics during the onset
of 50-W exercise was determined by fitting a single exponential
function to the V̇o2 response.
Results: In 14 patients without coronary restenosis, the
time constant of V̇o2 kinetics was
significantly shortened from (mean ± SD) 57.4 ± 12.6 before PTCA
to 48.2 ± 9.5 s after PTCA (p = 0.0035), indicating improved
kinetics of the V̇o2 response. In these
subjects, the peak V̇o2 obtained during
maximal exercise testing also increased from 23.1 ± 3.5 to
26.5 ± 3.2 mL/min/kg, respectively (p = 0.0005). However, there
was no improvement in these indexes in the patients who had restenosis
after undergoing PTCA (n = 3).
of cardiopulmonary exercise testing, which reflect an efficiency of
oxygen flow to the exercising muscle, can be used as an objective,
noninvasive, and cost-effective guide for understanding which patients
will not have coronary restenosis following PTCA.