Background Postoperative right ventricular (RV) dysfunction is an independent determinant for long-term morbidity and mortality in patients with mitral valve disease. We tested the hypothesis that preoperative exercise-induced pulmonary hypertension induces progressive RV dysfunction after surgical correction of mitral disease.
Methods We prospectively enrolled 19 patients (mean age 52±12 years, M:F = 7:12) with severe mitral stenosis or mitral regurgitation in whom mitral surgery was planned. Comprehensive 2D and Doppler echocardiography was performed at baseline and during supine bicycle exercise of the submaximal intensity (upto 70% of predicted maximal heart rate) before surgery. Echocardiography was repeated 6 months after surgery. Peak systolic tricuspid annulus velocity (S’T) was measured as a parameter of RV systolic function. Pulmonary artery systolic pressure (PASP) was estimated from the jet velocity of tricuspid regurgitation.
Results At baseline, mean resting and exercise PASP were 44.9 ± 12.7 mmHg, and 73.3 ± 17.7 mmHg, respectively. RV systolic function (S’T) significantly decreased after mitral valve surgery (10.2 ± 2.6 cm/s vs. 8.8 ± 1.7 cm/s, p=0.018). Preoperative resting PASP is not significantly related with postoperative S’T (p=0.133). However, preoperative exercise PASP (r=-0.514, p=0.042) and preoperative resting S’T (r=0.483, p=0.050) are negatively related with postoperative S’T. Age, left atrial size, left ventricular ejection fraction, preoperative exercise S’T did not show significant relationships with postoperative S’T. In multiple regression analysis, only preoperative exercise PASP is significantly correlated with postoperative S’T (R2=0.264, p=0.042)
Conclusions First, these results demonstrate that RV dysfunction can be progressively aggravated even after surgical correction of mitral valvular pathology. Second, PASP during exercise can be a good predictor of postoperative RV dysfunction. These findings underscore the importance of exercise-induced pulmonary hypertension as a possible cause of progressive RV dysfunction in patients with mitral valvular heart diseases.
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