Exercise tolerance in asymptomatic patients with moderate-severe valvular heart disease and preserved ejection fraction

Introduction: For asymptomatic patients with moderate-severe valvular heart disease, in whom symptoms may be obscured, objective exercise tolerance measures are warranted for decisions concerning physical activities and surgical treatment.

Material and methods: We compared 61 patients (39 with aortic stenosis, 22 with aortic or mitral regurgitation) to 23 controls without valvular heart disease but with indications for stress testing. All participants underwent cardiopulmonary function testing and dobutamine stress echocardiography. Blood was drawn before as well as after bicycle stress to assess high-sensitivity cardiac troponin T (hscTnT). Patients who underwent surgery were re-evaluated 1.5 ±0.9 years after the operation.

Results: Conventional bicycle test following guideline criteria revealed a pathologic result in 26% of the patients, whereas spiroergometry showed an objectively reduced exercise tolerance in 59%, reaching a prognostically relevant feature in 39%. Stress echocardiography detected a reduced systolic reserve in 33% and elevated filling pressures in 62%. These abnormalities were significantly less present in the control group (4, 17, 9, 9, 4% respectively, p < 0.05 each). Baseline hscTnT detected patients with the prognostically important feature of reduced exercise tolerance (area under the curve 0.689 (95% CI: 0.546-0.831), p = 0.015). Objective preoperative exercise tolerance predicted sustained cardiocirculatory and myocardial dysfunction postoperatively.

Conclusions: Cardiopulmonary function testing and dobutamine stress echocardiography identify exercise intolerance in patients with asymptomatic valvular heart disease beyond stress-test criteria recommended in recent guidelines. High-sensitivity cardiac troponin I may be of additional value. Results of these tests presage post-operative function.