The impact of pulmonary valve replacement on left ventricular mechanical efficiency in adult patients with tetralogy of fallot: a study with cardiac energetics

Purpose: Pulmonary valve replacement (PVR) improves right ventricular (RV) function in patients with tetralogy of Fallot (TOF). However, the impact of PVR on left ventricular (LV) function and the mechanism of improvement are still unclear. The purpose of this study is to clarify the impact of PVR on LV mechanical efficiency in adult patients with TOF. Methods: Fourteen patients with TOF (age 30.1±11.5 years) who underwent PVR for significant pulmonary insufficiency were enrolled in this study. We measured left ventricular end-diastolic volume index (LVEDVI), left ventricular end-systolic volume index (LVESVI), contractility (end-systolic elastance; Ees), afterload (effective arterial elastance; Ea), and mechanical efficiency (ventriculoarterial coupling; Ea/Ees and the rate of stroke work and pressure-volume area; SW/PVA) on the basis of the echocardiographic data before, after and late after PVR. Ees, Ea and SW/PVA were approximated as follows: Ees=mean arterial pressure/minimal ventricular volume, Ea = maximal ventricular pressure / (maximal ventricular volume-minimal ventricular volume), and SW/PVA=1 / (1 + 0.5 Ea/Ees). Results: LVEDVI, stroke volume and ejection fraction increased significantly after PVR. Contractility (Ees) did not change but afterload (Ea) decreased, and LV mechanical efficiency (Ea/Ees and SW/PVA) improved significantly. These changes were observed just after PVR, and further improvement was not noted in the late period. ![Figure][1] Hemodynamic changes after PVR Conclusions: LV efficiency improves after PVR. Increased pulmonary forward flow and relief of the compression from the RV increase LVEDVI and stroke volume. LV afterload decreases to adapt the increase of stroke volume without the change of contractility. These changes result in the improvement of LV mechanical efficiency. [1]: pending:yes