The appropriate opening of aortic valves is crucial for heart failure (HF) patients with left ventricular assist devices (LVADs). Nevertheless, up to the present time, aortic valve monitoring has not been performed in discharged patients. In this study, a mock-loop platform was developed to investigate the aortic valve performance in LVAD patients. An additional sluice valve was placed next to the aortic valve that when the sluice valve is manually closed, the aortic valve will remain closed; when the sluice valve is open, the aortic valve is opened or closed upon the pressures. The results showed that when the LVAD speed was below 2600 rpm, the aortic valve can be intermittently opened, while when the LVAD speed was over 2600 rpm, the aortic valve was persistently closed. The left ventricular end-systolic pressure (LVESP) was found to be an indicator of aortic valve closure that, upon the aortic valve closure LVESP suddenly decreased. The LVESP is suggested for future monitoring the status of the aortic valve for patients with implanted LVADs. The effects of heart failure (HF) degrees, circulation resistance, and aortic compliance on aortic valve closure were further studied. The results revealed that LVAD implantation in patients with early HF degrees will help to avoid persistent aortic valve closure.
FrazierOHMyersTJJarvikRK, et al. Research and development of an implantable, axial-flow left ventricular assist device: the Jarvik 2000 Heart. Ann Thorac Surg2001; 71: S125–S132; discussion S144–S146.
2.
SlaughterMSRogersJGMilanoCA, et al. Advanced heart failure treated with continuous-flow left ventricular assist device. New Engl J Med2009; 361: 2241–2251.
3.
KirklinJKNaftelDCKormosRL, et al. Third INTERMACS Annual Report: the evolution of destination therapy in the United States. J Heart Lung Transplant2011; 30: 115–123.
4.
KadakiaSMooreRAmburV, et al. Current status of the implantable LVAD. Gen Thorac Cardiovasc Surg2016; 64: 501–508.
5.
BarboneAHolmesJWHeerdtPM, et al. Comparison of right and left ventricular responses to left ventricular assist device support in patients with severe heart failure: a primary role of mechanical unloading underlying reverse remodeling. Circulation2001; 104: 670–675.
6.
GraneggerMMasettiMLaohasurayodhinR, et al. Continuous monitoring of aortic valve opening in rotary blood pump patients. IEEE Trans Biomed Eng2016; 63: 1201–1207.
7.
May-NewmanKEnriquez-AlmaguerLPosuwattanakulP, et al. Biomechanics of the aortic valve in the continuous flow VAD-Assisted heart. ASAIO J2010; 56: 301–308.
8.
GraneggerMSchimaHZimpferD, et al. Assessment of aortic valve opening during rotary blood pump support using pump signals. Artif Organs2014; 38: 290–297.
9.
GarciaMAZEnriquezLADembitskyW, et al. The effect of aortic valve incompetence on the hemodynamics of a continuous flow ventricular assist device in a mock circulation. ASAIO J2008; 54(3): 237–244.
10.
ReiderCMoonJRameshV, et al. Intraventricular thrombus formation in the LVAD-assisted heart studied in a mock circulatory loop. Meccanica2017; 52: 515–528.
11.
SalamonsenRFLimEGaddumN, et al. Theoretical foundations of a starling-like controller for rotary blood pumps. Artif Organs2012; 36: 787–796.
12.
CowgerJPaganiFDHaftJW, et al. The development of aortic insufficiency in left ventricular assist device-supported patients. Circ Heart Fail2010; 3: 668–674.
13.
PakSWUrielNTakayamaH, et al. Prevalence of de novo aortic insufficiency during long-term support with left ventricular assist devices. J Heart Lung Transplant2010; 29: 1172–1176.
14.
TolpenSJanmaatJReiderC, et al. Programmed speed reduction enables aortic valve opening and increased pulsatility in the LVAD-assisted heart. ASAIO J2015; 61: 540–547.
15.
TayamaEOhashiYNiimiY, et al. Estimation of the minimum pump speed to prevent regurgitation in the continuous flow left ventricular assist device: left ventricular drainage versus left atrial drainage. Artif Organs1997; 21: 1288–1291.
16.
TuzunEGregoricIDCongerJL, et al. The effect of intermittent low speed mode upon aortic valve opening in calves supported with a Jarvik 2000 axial flow device. ASAIO J2005; 51: 139–143.
17.
BishopCJMasonNOKfouryAG, et al. A novel non-invasive method to assess aortic valve opening in HeartMate II left ventricular assist device patients using a modified Karhunen-Loève transformation. J Heart Lung Transplant2010; 29: 27–31.
18.
CliffordRRobsonDGrossC, et al. Beat-to-beat detection of aortic valve opening in HeartWare left ventricular assist device patients. Artif Organs2019; 43: 458–566.
19.
WuYAllairePETaoG, et al. A bridge from short-term to long-term left ventricular assist device–experimental verification of a physiological controller. Artif Organs2004; 28: 927–932.
20.
May-NewmanKFisherBHaraM, et al. Mitral valve regurgitation in the LVAD-assisted heart studied in a mock circulatory loop. Cardiovasc Eng Technol2016; 7: 139–147.
21.
TayamaEOhashiYNiimiY, et al. The safety system for the rotary blood pump, combination of the valve and LVAD pulsatile mode: in vitro test. Artif Organs1998; 22: 342–345.
22.
FranchiniGGiovannielloFAmabiliM. Viscoelasticity of human descending thoracic aorta in a mock circulatory loop. Mech Behav Biomed Mater2022; 130: 105205.
23.
FerrariGBalasubramanianPTubaldiE, et al. Experiments on dynamic behaviour of a Dacron aortic graft in a mock circulatory loop. J Biomech2019; 86: 132–140.
24.
AmabiliMBalasubramanianPBozzoI, et al. Nonlinear dynamics of human aortas for material characterization. Phys Rev X2020; 10: 011015.
25.
HaghiashtianiGQiuKZhingre SanchezJD, et al. 3D printed patient-specific aortic root models with internal sensors for minimally invasive applications. Sci Adv2020; 6: eabb4641.
26.
VismaraRFioreGBManginiA, et al. A novel approach to the in vitro hydrodynamic study of the aortic valve: mock loop development and test. ASAIO J2010; 56: 279–284.
27.
GrahamJD. Treatment of severe aortic stenosis: experimental design, testing, and analysis of an aortic valve bypass apical cannula. Bibliography2010; 40: 1309–1322.
28.
ErikssonMJRosforsSRådegranK, et al. Effects of exercise on Doppler-derived pressure difference, valve resistance, and effective orifice area in different aortic valve prostheses of similar size. Am J Cardiol1999; 83: 619–622, A10.
29.
KimHJKimJZandiehO, et al. Piezoelectric layer embedded-microdiaphragm sensors for the determination of blood viscosity and density. Appl Phys Lett2014; 105: 153504.
30.
WeissWJRosenbergGSnyderAJ, et al. Steady state hemodynamic and energetic characterization of the Penn State/3M health care total artificial heart. ASAIO J1999; 45: 189–193.
31.
MaulTMKocyildirimEJohnsonCA, et al. In vitro and in vivo performance evaluation of the second developmental version of the PediaFlow pediatric ventricular assist device. Cardiovasc Eng Technol2011; 2: 253–262.
32.
AmabiliMBalasubramanianPFerrariG, et al. Identification of viscoelastic properties of Dacron aortic grafts subjected to physiological pulsatile flow. J Mech Behav Biomed Mater2020; 110: 103804.
