Abstract 13214: Right Ventricular-Vascular Coupling in Acute Hemodynamic Stress: A Simple Method of Estimation and Relationship With Right Ventricular Ejection Fraction and Afterload

Objectives: Gold standard of right ventricular (RV) function is ratio of end-systolic to arterial elastance from synchronized volume and pressure measurements. Quantification of ventricular-vascular coupling (VVc) using non-simultaneous common right heart catheterization and cardiac imaging has been described. Hypothesis: VVc estimated from simultaneous pressure and volume measurements using Swan-Ganz TM (Edwards Lifesciences, Irvine, CA) advanced technology catheters would be feasible and clinically relevant. Methods: 32 mechanically ventilated adult critically ill trauma/general surgery patients were enrolled within 6 hours of admission. Hemodynamics were transduced every 12 hours for 48 hours. VVc was quantified as ratio of pulmonary artery (PA) effective elastance (E a ) to RV maximal end-systolic elastance (E max ). Mean PA pressure (mPAP) was used as surrogate of RV end-systolic pressure. Right ventricular end-systolic volume index (ESVI) was calculated as difference of end-diastolic volume index and stroke volume index (SVI). E(a) was calculated as (mPAP - PCWP)/SVI and E(max) as mPAP/ESVI. Results: Serial E a /E max inversely correlated with RV ejection fraction (RVEF) (r = -0.89, p <0.001; r = -0.57, p = 0.001; r = -0.73, p <0.001; r = -0.38, p =0.052, and r -0.55, p <0.03) (Figure 1) and pulmonary arterial capacitance (PAC) (r = -0.59, -0.64, -0.49, -0.53, and -0.41, p ≤ 0.03). Pulmonary vascular resistance (PVR) correlated with E a /E max (r = 0.66, 0.61, 0.68, 0.66, 0.52, p ≤ 0.004). Non-survivors (n = 7) had higher E a /E max (indicating uncoupling) at 48 hours (2.3 ± 1.8 vs. 1.4 ± 1.8, p = 0.036). AUC for Ea/Emax at 48 hours and mortality was comparable to RVEF. Conclusions: In mechanically ventilated critically ill and/or injured adults, estimation of VVc using advanced technology pulmonary artery catheter is feasible. E a /E max is related to PVR and inversely related to RVEF and PAC. Estimation of E a /E max may assist in optimization of resuscitation.