Abstract 11450: Comparison of Simplified (Single-beat) Estimates to Measured Right Ventricular End-Systolic Elastance and RV-Pulmonary Vascular Coupling in Patients With Pulmonary Hypertension
Introduction: Pressure-volume (PV) relationships derived from multiple beats enables calculation of relatively load-insensitive contractility indexes such as end-systolic elastance (Ees), integrated measures of afterload such as the effective arterial elastance (Ea), and their ratio (Ees/Ea) which describes ventricular-vascular coupling. Right ventricular (RV) single-beat estimates of these variables are increasingly being used in clinical studies yet have not been compared to human multiple-beat data.
Methods: Patients referred for a right heart catheterization for diagnosis and/or management of pulmonary hypertension were prospectively enrolled. Right ventricular PV loops (n=30) were constructed using the Valsalva maneuver to alter preload.
Results: End-systolic pressure (ESP) was closely approximated by right ventricular systolic pressure (RVSP) (Figure 1A), and therefore, Ea was best estimated as RVSP/stroke volume (SV). Three single beat methods to calculate Ees were considered: 1) sine-wave fit to isovolumic portions of RV pressure tracing, 2) V0=0 (ESP/end-systolic volume), and 3) normalized time varying elastance En(tn) curve. Compared with multi-beat data (EesPV), sine-wave EesSB underestimated EesPV, particularly when contractility was high (Figure 1B). The V0=0 approach markedly underestimated EesPV (Figure 1C). RV En(tn) curves showed high variability (Figure 1D) and thus are not useful to estimate Ees.
Conclusions: Ea is best estimated as RVSP/SV. Right ventricular single-beat estimates of Ees show a significant underestimation bias especially under situations of enhanced contractility. Invasive pressure-volume assessment with preload reduction techniques remains the only method to assess these contractile parameters precisely.
Author Disclosures: R.J. Tedford: Consultant/Advisory Board; Modest; merck. B.W. Kelemen: None. S.C. Mathai: None. R. Damico: None. T.M. Kolb: None. E. Tampakakis: None. A.A. Shah: None. Z.H. McMahan: None. F. Boin: None. C.P. Corona-Villalobos: None. A.C. Bacher: None. P.M. Hassoun: None. D.A. Kass: None.
- © 2014 by American Heart Association, Inc.