New Insights into Right Ventricular Function among Patients with Left Ventricular Assist Devices Using High Fidelity Conductance Catheters to Generate Real Time Pressure Volume Loops

Right Ventricular Pressure-Volume Analysis During Left Ventricular Assist Device Speed Optimization Studies: Insights Into Interventricular Interactions and Right Ventricular Failure

BACKGROUND

Interventricular interaction, which refers to the impact of left ventricular (LV) function on right ventricular (RV) function and vice versa, has been implicated in the pathogenesis of RV failure in LV assist device (LVAD) recipients. We sought to understand more about interventricular interaction by quantifying changes in the RV systolic and diastolic function with varying LVAD speeds.

METHODS AND RESULTS

Four patients (ages 22-69 years, 75% male, and 25% with ischemic cardiomyopathy) underwent a protocolized hemodynamic ramp test within 12 months of LVAD implantation where RV pressure-volume loops were recorded with a conductance catheter. The end-systolic PV relationship and end-diastolic PV relationship were compared using the V₂₀ and V₁₀ indices (volumes at which end-systolic PV relationship and end-diastolic PV relationship reach a pressure of 20 and 10 mm Hg, respectively). The ∆V₂₀ and ∆V₁₀ refer to the change in V₂₀ and V₁₀ from the minimum to maximum LVAD speeds. RV PV loops demonstrated variable changes in systolic and diastolic function with increasing LVAD speed. The end-systolic PV relationship changed in 1 patient (patient 2, ∆V₂₀ = 23.5 mL), reflecting a decrease in systolic function with increased speed, and was unchanged in 3 patients (average ∆V₂₀ = 7.4 mL). The end-diastolic PV relationship changed with increasing speed in 3 of 4 patients (average ∆V₁₀ = 12.5 mL), indicating an increase in ventricular compliance, and remained unchanged in one participant (patient 1; ∆V₁₀ = 4.0 mL).

CONCLUSIONS

Interventricular interaction can improve RV compliance and impair systolic function, but the overall effect on RV performance in this pilot investigation is heterogeneous. Further research is required to understand which patient characteristics and hemodynamic parameters influence the net impact of interventricular interaction.