Pressure‐based estimation of right ventricular ejection fraction

Abstract

Aims A method for estimating right ventricular ejection fraction (RVEF) from RV pressure waveforms was recently validated in an experimental model. Currently, cardiac magnetic resonance imaging (MRI) is the clinical reference standard for measurement of RVEF in pulmonary arterial hypertension (PAH). The present study was designed to test the hypothesis that the pressure-based method can detect clinically significant reductions in RVEF as determined by cardiac MRI in patients with PAH. Methods and results RVEF estimates derived from analysis of RV pressure waveforms recorded during right heart catheterization (RHC) in 25 patients were compared with cardiac MRI measurements of RVEF obtained within 24 h. Three investigators blinded to cardiac MRI results independently performed pressure-based RVEF estimation with the mean of their results used for comparison. Linear regression was used to assess correlation, and a receiver operator characteristic (ROC) curve was derived to define ability of the pressure-based method to detect a maladaptive RV response, defined as RVEF <35% on cardiac MRI. In 23 patients, an automated adaptation of the pressure-based RVEF method was also applied as proof of concept for beat-to-beat RVEF monitoring. The study cohort was comprised of 16 female and 9 male PAH patients with an average age of 53 ± 13 years. RVEF measured by cardiac MRI ranged from 16% to 57% (mean 37.7 ± 11.6%), and estimated RVEF from 15% to 54% (mean 36.2 ± 11.2%; P = 0.6). Measured and estimated RVEF were significantly correlated (r 2 = 0.78; P < 0.0001). ROC curve analysis demonstrated an area under the curve of 0.94 ± 0.04 with a sensitivity of 81% and specificity of 85% for predicting a maladaptive RV response. As a secondary outcome, with the recognized limitation of non-coincident measures, Bland-Altman analysis was performed and indicated minimal bias for estimated RVEF (À1.5%) with limits of agreement of ± 10.9%. Adaptation of the pressure-based estimation method to provide beat-to-beat RVEF also demonstrated significant correlation between the median beat-to-beat value over 10 s with cardiac MRI (r 2 = 0.66; P < 0.001), and an area under the ROC curve of 0.94 ± 0.04 (CI = 0.86 to 1.00) with sensitivity and specificity of 78% and 86%, respectively, for predicting a maladaptive RV response. Conclusions Pressure-based estimation of RVEF correlates with cardiac MRI and detects clinically significant reductions in RVEF. Study results support potential utility of pressure-based RVEF estimation for assessing the response to diagnostic or therapeutic interventions during RHC.

Pressure‐based beat‐to‐beat right ventricular ejection fraction and Tau from continuous measured ventricular pressures in COVID‐19 ARDS patients

“…However, no consistent relationship between PH defined as mean PAP of ≥20 mm hg and an RVEF ≤ 45% could be shown in that study. 22 In contrast, Heerdt et al 7,8 showed recently, that pressure-based single beat estimation of RVEF in patients with PH correlated with RVEF measured by MRI. Moreover, in their comparison, they found RVEF as low as 15% with both the single beat method and MRI in the same patients.…”

“…The novel single‐beat pressure approach for the calculation of RVEF has been validated by cardiac MRI in two studies with 31 patients suffering from PH or heart failure with preserved ejection fraction. 7 , 8 For the calculation of Tau, we used the logistic approach as evaluated and proposed by Ogilvie et al 10 We tested the reliability of our algorithms by manual evaluation of both RVEF and Tau, showing excellent correlation with automated calculation by our written software.…”

“… 13 , 14 , 15 , 16 Recently Heerdt et al. 7 , 8 proposed the use of a Weibull function instead of a sinus function.…”

“…Our next steps in the future are to translate our singlebeat right ventricular pressure offline calculation of RVEF and Tau into continuous online monitoring of RVEF and Tau, thus introducing a continuous estimation of right ventricular systolic and diastolic function. 7,8,34 Ultimately, online remote control of changes in hemodynamics with continuous long-term monitoring of RVSP and RVEF as a diagnostic and therapeutic target in patients with acute and chronic heart failure seems to be possible and obviously has the potential to reduce hospitalization rates as well as mortality. 29,35 AUTHOR CONTRIBUTIONS Matthias Gaertner was responsible for the collection and preparation of the data and has run the statistical evaluation.…”

“…Following the administration of pulmonary vasodilators, we also found a significant decrease in right ventricular systolic pressure (RVSP) over time in the survivors but not in the nonsurvivors. 6 In the present paper, we have used our final patient database of 39 mechanically ventilated patients with severe ARDS caused by COVID‐19 pneumonia to calculate the right ventricular ejection fraction (RVEF) as well as the time constant Tau of the right ventricular isovolumetric relaxation time Tau from the continuous invasive measured right ventricular pressure curves using a modification of the recently published single‐beat approaches for the calculation of RVEF 7 , 8 and Tau. 9 , 10 …”