Pulmonary arterial hypertension (PAH) is associated with high morbidity and mortality. Cardiac Magnet resonance tomography (MRI) has gained importance in diagnostic of right ventricular function. MRI-derived-Strain-analysis of the right ventricle is a promising tool for assessing right ventricular function. However, strain-analysis of the right ventricle has not been compared to ventriculo-arterial coupling yet.
28 consecutive PAH-patients were imaged by 1.5 T-MRI (Siemens Healthcare, Germany) and analysed for circumferential, radial and longitudinal strain with an analysing software (Circle cardiovascular imaging Inc, Canada). Conductance catheter (4F, CD Leycom, Hengelo, The Netherlands), CD Leycom, Hengelo, The Netherlands]) and Right heart catheter were done the day after MRI. Ventricular-arterial-coupling measurements were based on measurements of pressure-volume-loops of the right ventricle using a single-beat-estimation of Ventricular elastance (Ees) (Pmax-ESP/SV).
In 28 patients (age: 56±13 years) with PAH (mean pulmonary arterial pressure :40±13 mmHg, pulmonary vascular resistance: median 498 [IQR 688-338] dyn) the relationship between rightventricular Ees (median 0,48 [IQR 0,78-0,35] and arterial elastance (Ea) (median 0,74 [IQR 1,0-0,44] Ees/Ea (median 0,73 ±0,44) was compared with MRI-derived strain. We observed significant correlations between MRI- RV global longitudinal strain (Rho -0,5, p: 0,007), RV global radial strain (Rho: 0,46, p: 0,014), LV radial strain (Rho:0,59, p: 0,001) and LV circumferential strain (-0,575, p: 0,001).
Right ventricular-arterial coupling significantly correlates with right and left ventricular strain. The correlation with left ventricular strain indicates an improvement of left ventricular function in higher right ventricular Ees/Ea relationships and highlights the importance of ventricular interdependency.