Lack of correlation between haemodynamic and cardiopulmonary exercise capacity improvement after catheter-balloon mitral valvuloplasty

The long-term effects of percutaneous transvenous mitral commissurotomy on exercise capacity and ventilation were investigated to determine whether a dissociation between haemodynamic improvement and exercise capacity increase occurs in patients with mitral stenosis. Eighteen patients aged 45 +/- 12.3 years (mean +/- SD) with symptomatic mitral stenosis performed a symptom-limited bicycle exercise test while respiratory gases were measured before and 6 months after percutaneous transvenous mitral commissurotomy. The mitral valve area increased from 1.07 +/- 0.22 to 1.98 +/- 0.67 cm2. P < 0.0001 and the mean mitral gradient decreased from 12.9 +/- 4.5 to 5.3 +/- 4.8 mmHg, P < 0.001, without a significant increase in cardiac output index (from 2.64 +/- 0.55 to 2.77 +/- 0.561, min-1, m-2, P = ns). This haemodynamic improvement was still present at the 6-month follow-up catheterization. Mean exercise workload and peak oxygen uptake increased 6 months after percutaneous transvenous mitral commissurotomy from 88.3 +/- 28.1 to 97.8 +/- 25.1 watts, P = 0.01, and from 18.1 +/- 5.3 to 19.9 +/- 4.8 ml. kg-1. min-1, P < 0.05. Total ventilation, ventilatory equivalents and oxygen pulse at the end of the exercise test remained unchanged. Correlations between peak oxygen or exercise capacity improvement and mitral valve area increase were poor (r = 0.27, P = ns, r = 0.24, P = ns). This clear dissociation between haemodynamic improvement and improvements in minor exercise capacity after percutaneous transvenous mitral commissurotomy suggests that peripheral alterations persist. Future studies in which patients are trained after valvuloplasty may be helpful.