Abstract
Aortic insufficiency (AI) is a crucial complication during continuous-flow left ventricular assist device (LVAD) support. Our previous clinical study suggested that a larger angle between the outflow graft and the aorta (O–A angle) could cause AI progression. This study examined the effect of the O–A angle on the hemodynamics of AI under LVAD support in an acute animal experimental model. An LVAD was installed in seven calves, with the inflow cannula inserted from the LV apex and with the outflow graft sutured at the ascending aorta. The AI model was made using a temporary inferior vena cava filter inserted from the LV apex and placed at the aortic valve. Cardiac dysfunction was induced by continuous beta-blocker infusion. Hemodynamic values and the myocardial oxygen extraction rate (O2ER) were evaluated at three O–A angles (45°, 90°, and 135°) over three levels of AI (none, Sellers I–II AI, and Sellers III–IV AI). The recirculation rate, defined as the percentage of regurgitation flow to LVAD output, was calculated. Systemic flow tended to decrease with a larger O–A angle. The recirculation rate was significantly increased with a larger O–A angle (22, 23, and 31% at 45°, 90°, and 135° in Sellers III–IV AI, respectively). Coronary artery flow was decreased at a larger O–A angle (86, 76 and 75 mL/min at 45°, 90°, and 135° in Sellers I–II AI, respectively, and 77, 67, and 56 mL/min at 45°, 90°, and 135° in Sellers III–IV AI, respectively). O2ER tended to increase with a larger O–A angle (40, 43, and 49% at 45°, 90°, and 135° in Sellers III–IV AI, respectively). A larger O–A angle can increase the recirculation due to AI and can be disadvantageous to LVAD-AI hemodynamics and myocardial oxygen metabolism.
Similar content being viewed by others
References
Toda K, Fujita T, Domae K, Shimahara Y, Kobayashi J, Nakatani T. Late aortic insufficiency related to poor prognosis during left ventricular assist device support. Ann Thorac Surg. 2011;92:929–34.
Pak SW, Uriel N, Takayama H, Cappleman S, Song R, Colombo PC, et al. Prevalence of de novo aortic insufficiency during long-term support with left ventricular assist devices. J Heart Lung Transplant. 2010;29:1172–6.
Rajagopal K, Daneshmand MA, Patel CB, Ganapathi AM, Schechter MA, Rogers JG, et al. Natural history and clinical effect of aortic valve regurgitation after left ventricular assist device implantation. J Thorac Cardiovasc Surg. 2013;145:1373–9.
Cowger J, Pagani FD, Haft JW, Romano MA, Aaronson KD, Kolias TJ. The development of aortic insufficiency in left ventricular assist device-supported patients. Circ Heart Fail. 2010;3:668–74.
Patil NP, Sabashnikov A, Mohite PN, Garcia D, Weymann A, Zych B, et al. De novo aortic regurgitation after continuous-flow left ventricular assist device implantation. Ann Thorac Surg. 2014;98:850–7.
Atkins BZ, Hashmi ZA, Ganapathi AM, Harrison JK, Hughes GC, Rogers JG, et al. Surgical correction of aortic valve insufficiency after left ventricular assist device implantation. J Thorac Cardiovasc Surg. 2013;146:1247–52.
Fujita T, Kobayashi J, Hata H, Seguchi O, Sato T, Yanase M, et al. Aortic valve closure for rapidly deteriorated aortic insufficiency after continuous flow left ventricular assist device implantation. J Artif Organs. 2013;16:98–100.
May-Newman K, Hillen B, Dembitsky W. Effect of left ventricular assist device outflow conduit anastomosis location on flow patterns in the native aorta. ASAIO J. 2006;52:132–9.
Aliseda A, Chivukula VK, McGah P, Prisco AR, Beckman JA, Garcia GJ, et al. LVAD outflow graft angle and thrombosis risk. ASAIO J. 2017;63:14–23.
Benk C, Mauch A, Beyersdorf F, Klemm R, Russe M, Blanke P, et al. Effect of cannula position in the thoracic aorta with continuous left ventricular support: four-dimensional flow-sensitive magnetic resonance imaging in an in vitro model. Eur J Cardiothorac Surg. 2013;44:551–8.
Iizuka K, Nishinaka T, Ichihara Y, Miyamoto T, Yamazaki K. Outflow graft anastomosis site design could be correlated to aortic valve regurgitation under left ventricular assist device support. J Artif Organs. 2018;21:150–5
Iizuka K, Nishinaka T, Takewa Y, Yamazaki K, Tatsumi E. The influence of pump rotation speed on hemodynamics and myocardial oxygen metabolism in left ventricular assist device support with aortic valve regurgitation. J Artif Organs. 2017;20:194–9.
Iizuka K, Nishinaka T, Naito N, Akiyama D, Takewa Y, Yamazaki K, et al. Left heart pressures can be the key to know the limitation of left ventricular assist device support against progression of aortic insufficiency. J Artif Organs. 2018. https://doi.org/10.1007/s10047-018-1027-4
Yamazaki K, Saito S, Kihara S, Tagusari O, Kurosawa H. Completely pulsatile high flow circulatory support with a constant-speed centrifugal blood pump: mechanisms and early clinical observations. Gen Thorac Cardiovasc Surg. 2007;55:158–62.
Yamazaki K, Kihara S, Akimoto T, Tagusari O, Kawai A, Umezu M, et al. EVAHEART an implantable centrifugal blood pump for long-term circulatory support. Jpn J Thorac Cardiovasc Surg. 2002;50:461–5.
Kanda Y. Investigation of the freely available easy-to-use software ‘EZR’ for medical statistics. Bone Marrow Transplant. 2013;48:452–8.
Acknowledgements
The authors gratefully acknowledge the work of past and present members of our laboratory. This work was supported by JSPS KAKENHI Grant Number JP17K16602. This work was also supported by Yoshimi Memorial T.M.P. Grant from JSAO 2015.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
Kenji Yamazaki has received consulting fees from Sun Medical Technology Research Corporation (Nagano, Japan). The other authors declare that they have no conflict of interest.
Rights and permissions
About this article
Cite this article
Iizuka, K., Nishinaka, T., Akiyama, D. et al. The angle of the outflow graft to the aorta can affect recirculation due to aortic insufficiency under left ventricular assist device support. J Artif Organs 21, 399–404 (2018). https://doi.org/10.1007/s10047-018-1064-z
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10047-018-1064-z