Right Ventricular Ejection Efficiency: A New Echocardiographic Measure of Mechanical Performance in Chronic Pulmonary Hypertension

BACKGROUND: The severity of pulmonary vascular resistance (PVR) is known to be a critical determinant of right ventricular (RV) systolic function; this relationship remains poorly characterized. We therefore, designed a study to examine the relationship that exists between echocardiographically measured PVR and maximal tricuspid annular plane systolic excursion (TAPSE) to gain some insight regarding RV ejection efficiency (RVEe) in patients with chronic pulmonary hypertension (cPH). METHODS: Standard echocardiographic measures of RV size and systolic performance were recorded from 95 patients (age 54 ± 15 years and pulmonary artery systolic pressures [PASP] that range from 20 to 125 mmHg). For this study, RVEe was defined as TAPSE/Echocardiographic PVR. RESULTS: A strong negative correlation (R(2) = -0.51, P < 0.001) was seen between TAPSE and PASP; however, a power curve trend line fit the relationship between RVEe and PASP (R(2) = 0.77; P < 0.01). In a multiple regression analysis, abnormal pulmonary pressures were better identified when RVEe (P < 0.0001) was used. CONCLUSIONS: Based on these results, it appears that measurement of RVEe might be extremely useful for the assessment of RV mechanics and plasticity. The power curve relationship clearly demonstrates that minimal changes in PASP (up to 50 mmHg) result in dramatic reductions in RVEe. A steady decline in RVEe, though at a lower rate, continues to occur with increasing PASP. Additional studies are required using RVEe into a functional RV imaging algorithm and determine if RVEe correlates with development of symptoms, response to therapy and overall clinical outcomes.