Trans-aortic valvular flow dynamics and left ventricular ejection fraction for monitoring recovery of patients with left ventricular systolic heart failure

Durable mechanical circulatory support in the form of left ventricular (LV) assist device (LVAD) therapy is increasingly considered in the context of the recovery of native cardiac function. Progressive improvement in LV function may facilitate LVAD explantation and a resultant reduction in device-related risk. However, ascertaining LV recovery remains a challenge. In this study, we investigated the use of trans-aortic valvular flow rate and trans-LVAD flow rate to assess native LV systolic function using a well-established lumped parameter model of the mechanically assisted LV with pre-existing systolic dysfunction. Trans Aortic Valvular Ejection Fraction (TAVEF) was specifically found to characterize the preload-independent contractility of the LV. It demonstrated excellent sensitivity to simulated pharmacodynamic stress tests and volume infusion tests. TAVEF may prove to be useful in the ascertainment of LV recovery in LVAD-supported LVs with pre-existing LV systolic dysfunction. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work was supported by and performed by contractors of the US Government Grant, W81XWH2010387. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Not Applicable The details of the IRB/oversight body that provided approval or exemption for the research described are given below: No clinical study was done for this manuscript and hence no IRB protocols have been included. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Not Applicable I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Not Applicable I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Not Applicable No additional data is available and all the data used in the study are included in the manuscript and supplemental publication materials. * AoV : Aortic Valve AoVC : Persistent Aortic Valve Closure BTR : Bridge to Recovery CO : Cardiac Output (lpm) CVS : Cardiovascular System DBP : Diastolic Blood Pressure (mmHg) DP : Dopamine Emax : Maximal Elastance EDV : End-diastolic Volume (ml) ESP : End-Systolic pressure in mmHg ESV : End-Systolic Volume (ml) LVAD : Left Ventricular Assist Device LVEF : Left Ventricular Ejection Fraction MAP : Mean Arterial Pressure (mmHg) MCS : Mechanical Circulatory Support NYHA : New York Heart Association RPM : Rotations Per Minute SBP : Systolic Blood Pressure (mmHg) SNP : Sodium Nitroprusside SoS : System of Systems SV : Stroke Volume (ml) (=EDV – ESV) TBV : Total Blood Volume TAVEF : Trans-Aortic Valvular Ejection Fraction TAVF : Trans-Aortic Valvular Flow TAVO : Trans-Aortic Valvular Output TVF : Trans-VAD Flow VAD : Ventricular Assist Device VBE : Volume in Left Ventricle Before Ejection Phase