Relationship between mean pulmonary pressure to cardiac output slope and peak pulmonary pressure during supine ergometry in mitral regurgitation: the effect of underlying etiology

Abstract Introduction Exercise-induced pulmonary hypertension, defined by a mean pulmonary arterial pressure over cardiac output slope >3 mmHg/L/min, has been introduced in recent guidelines. Purpose To assess the effect of the underlying etiology of mitral regurgitation (MR) on the exercise induced changes of pulmonary pressure and detect potential prognostic significance of mean pulmonary arterial pressure over cardiac output. Methods One hundred eight "asymptomatic" patients (pts) with moderate to severe MR, followed up on valve clinic in a tertiary center (age 61±16), were referred for Ex. Forty-one had myxomatous substrat(Myx), 39 fibroelastic deficiency (FD), 15 functional LV MR (LVfn) and 13 functional atrial MR (ATRfn). Events (decision for surgery, NYHA worsening) during a follow up of 34±25 months occurred in 20 pts. The following parameters (mean±SD) were estimated at R/Ex: Biplane LV end-diastolic volume, ejection fraction (EF%), stroke volume, longitudinal strain, systolic tricuspid peak/mean gradient (TRPG/TRMG), transmitral E/e. The TRMG/cardiac output (CO) slope was estimated during R/Ex. Results Pts with events vs no events had marginal difference in the estimated TRMG/CO slope (4.2±3.4 vs 4.5±2.8 mmHg/L/min). A TRPG >55 mmHg was found in 33 pts, with 31/33 having also a TRMG/CO slope>3 mmHg/L/min, thus implying a 94% concordance for positive criterion for abnormal response. However, when the 75 pts with a lower than 55 mmHg TRPG were considered, then only 25/75 had a concordant normal value of 55 mmHg was performed separately in each MR subgroup, then the following kappa agreement coefficients were estimated: For Myx: 0.2, (p=0.08), for FD: 0.12, (ns), for LVfn: 0.36, (p=0.07), for ATRfn: 0.12 (ns). Binary logistic regression analysis for outcome, including EF at R/Ex, strain at R/Ex and both 3 mmHg/L/min, peak TRPG categories, finally selected at first step TRPG category and then the TRMG/CO category (exp(B) 6.7/3.3, p55mmHg which contributed finally to the outcome (figures 1-2). Conclusion In "asymptomatic" moderate to severe MR, the relationship between mean pulmonary pressure to cardiac output slope and peak pulmonary pressure criteria for abnormal responses is affected by the MR etiology.