Simple and Short-term Inspiration Training Accelerates Recovery from Residual Pulmonary Hypertension after Mitral Valve Surgery: A randomized control trial

Abstract

Background: Residual pulmonary hypertension after mitral valve surgery predicts a worse prognosis. This study aimed to explore the effect of inspiratory muscle training on functional capacity and pulmonary artery pressure in patients with residual pulmonary hypertension after mitral valve surgery. Methods: Forty-three patients with residual pulmonary hypertension soon after mitral valve repair or replacement surgery were consecutively enrolled in this randomised controlled trial. They were randomly allocated to either an intervention group (n=22) or a control group (n=21). Both groups participated in usual 10-12 sessions of supervised aerobic exercise training, with low to moderate intensity. The subjects in the intervention group participated in additional inspiratory muscle training using an incentive spirometer with a series of 10-12 inspiration repetitions of 50% of maximum inspiratory volume in each aerobic session. Echocardiography and the 6-minute walking test were performed before and after the programme. Results: The patients were 70% female, mean age 43.5+/-13 years. Both groups had similar baseline characteristics. The systolic pulmonary artery pressure declined from 51(43-68) mmHg to 35 (29-39) mmHg, p<0.001 in intervention group, and from 46(43-55) mmHg to  43(40-51)mmHg, p<0.01 in control group. The reduction was higher in the intervention group than in the control group, 16 (12-30) vs 3.5 (2-4) mmHg respectively, p<0.001, and in patients with higher baseline systolic pulmonary artery pressure. The 6-minute walk test distance increased from 308(242-353) meters to 407(377-433) meter, p<0.01 in intervention group, and from 353(334-381) meter to 391(376-429) meter, p<0.01 in control group. The improvement was higher in the intervention group than in control group, 101 (93-131) vs 48 (35-53) meter respectively, p<0.001. Conclusion: Adding inspiratory muscle training to a usual exercise programme resulted in faster recovery from residual pulmonary hypertension and higher increase in functional capacity.