Cardiopulmonary responses to exercise and its utility in patients with aortic stenosis

Abstract

Utility of cardiopulmonary exercise test is unknown in patients with aortic stenosis. In this retrospective study, we examined the maximal indexes of cardiopulmonary testing at peak exercise in 155 consecutive patients with aortic valve area of ≤ 1.5 cm(2) who were referred for this test. The patients were passively followed up to assess their effect on the primary end point of all-cause mortality. We found that the absolute peak oxygen consumption (VO2) was significantly reduced in these patients, with age and gender-predicted peak VO2 of 80 ± 23%. Peak VO2 was markedly reduced (<80% of predicted) in 54% of patients. During a follow-up of 5 ± 4 years, a total of 41 patients died, and 72 underwent aortic valve replacement. Survival was significantly better in patients with higher absolute peak VO2 (hazard ratio [HR] 0.87, 95% confidence interval [CI] 0.80 to 0.93, p <0.001) and higher oxygen pulse (HR 0.80, 95% CI 0.74 to 0.9, p <0.001). In 83 patients who did not undergo valve replacement, higher peak VO2 and oxygen pulse were associated with better survival (HR 0.83, 95% CI 0.71 to 0.97, p = 0.024 and HR 0.80, 95% CI 0.66 to 0.96, p = 0.02, respectively). In conclusion, the peak VO2 is significantly reduced in patients with aortic stenosis. Higher peak VO2 is independently associated with better survival in these patients irrespective of whether they undergo valve replacement.