Pulmonary artery pressure (PAP) and right ventricular (RV) function have shown their value in the prognostic evaluation of patients with mitral valve prolapse (MVP). Echocardiography, including pressure estimation and volume measurement by 3D, allows an approach of right ventriculo-arterial coupling (RVAC) and assessment of the RV-PA unit.

Thirty healthy controls patients and 53 patients with MVP (34 in group MVP1 with no or mild mitral regurgitation (MR) and 19 in group MVP2) with moderate to severe MR underwent echocardiography including 3D RV acquisition. RV end-systolic volume (ESV), end-diastolic volume (EDV), stroke volume (SV) (mL) and ejection fraction (EF) (%) were obtained 3D echo (3DE) volumetric analysis (GE, EchoPac). mPAP was estimated from echo using Chemla's formula (mPAP=0.61×sPAP+2mmHg). Pulmonary artery effective elastance (Ea) was estimated as mPAP/SV (mmHg/mL), RV maximal end-systolic elastance (Emax) as mPAP/ESV (mmHg/mL), and RVAC as Ea/Emax. Ea, Emax and RVAC were compared between the 3 groups of patients unsing ANOVA.

Mean LVEF, TAPSE, mPAP were similar in the 3 groups. RVEDV (Nl: 81.3±19.2; MVP1: 81.5±23.1; MVP2: 92.7±26.4, ns) and RVEF (Nl: 50.4±4.4; MVP1: 49.2±5.6; MVP2: 47.1±5.5,ns) were similar in the 3 groups but not RVESV (Nl: 39.9±9.8; MVP1: 41.6±13.4; MVP2: 49.2±15.7, P=0.05). Ea (Nl: 0.41±0.12; MVP1: 0.45±0.16; MVP2: 0.48±0.30, ns) and E max (Nl: 0.42±0.11; MVP1: 0.45±0.18; MVP2: 0.43±0.25, ns) were not significantly different but RVAC was significantly different (Nl: 0.99±0.17; MVP1: 1.06±0.23; MVP2: 1.15±0.25, P=0.04).

3D echocardiography is able to reveal subtle changes in RV-PA unit equilibrium. Together with an increase in RV end-systolic volume, our study reveals a progressive alteration in RVAC in parallel with the severity of MR in patients with MVP as compared to normal patients.