title: What Is the Optimal Setting for a Continuous-Flow Left Ventricular Assist Device in Severe Mitral Regurgitation?
abstract: Excessive left ventricular (LV) volume unloading can affect right ventricular (RV) function by causing a leftward shift of the interventricular septum in patients with mitral regurgitation (MR) receiving left ventricular assist device (LVAD) support. Optimal settings for the LVAD should be chosen to appropriately control the MR without causing RV dysfunction. In this study, we assessed the utility of our electrocardiogram-synchronized rotational speed (RS) modulation system along with a continuous-flow LVAD in a goat model of MR. We implanted EVAHEART devices after left thoracotomy in six adult goats weighing 66.4 ± 10.7 kg. Severe MR was induced through inflation of a temporary inferior vena cava filter placed within the mitral valve. We evaluated total flow (TF; the sum of aortic flow and pump flow [PF]), RV fractional area change (RVFAC) calculated by echocardiography, left atrial pressure (LAP), LV end-diastolic pressure (LVEDP), LV end-diastolic volume (LVEDV), and LV stroke work (LVSW) with a bypass rate (PF divided by TF) of 100% under four conditions: circuit-clamp, continuous mode, co-pulse mode (increased RS during systole), and counter-pulse mode (increased RS during diastole). TF tended to be higher in the counter-pulse mode. Moreover, RVFAC was significantly higher in the counter-pulse mode than in the co-pulse mode, whereas LAP was significantly lower in all driving modes than in the circuit-clamp condition. Furthermore, LVEDP, LVEDV, and LVSW were significantly lower in the counter-pulse mode than in the circuit-clamp condition. The counter-pulse mode of our RS modulation system used with a continuous-flow LVAD may offer favorable control of MR while minimizing RV dysfunction.
authors.affiliation: Department of Artificial Organs, National Cerebral and Cardiovascular Center, Research Institute, Osaka.
authors.forename: Noritsugu
authors.initials: N
authors.lastname: Naito
authors.affiliation: Department of Cardiac Surgery, Tokyo Metropolitan Geriatric Hospital.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nishimura
authors.affiliation: Department of Artificial Organs, National Cerebral and Cardiovascular Center, Research Institute, Osaka.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Takewa
authors.affiliation: Department of Artificial Organs, National Cerebral and Cardiovascular Center, Research Institute, Osaka.
authors.forename: Satoru
authors.initials: S
authors.lastname: Kishimoto
authors.affiliation: Department of Cardiothoracic Surgery, The University of Tokyo, Tokyo, Japan.
authors.forename: Kazuma
authors.initials: K
authors.lastname: Date
authors.affiliation: Department of Cardiothoracic Surgery, The University of Tokyo, Tokyo, Japan.
authors.forename: Akihide
authors.initials: A
authors.lastname: Umeki
authors.affiliation: Department of Cardiothoracic Surgery, The University of Tokyo, Tokyo, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Ando
authors.affiliation: Department of Cardiothoracic Surgery, The University of Tokyo, Tokyo, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Ono
authors.affiliation: Department of Artificial Organs, National Cerebral and Cardiovascular Center, Research Institute, Osaka.
authors.forename: Eisuke
authors.initials: E
authors.lastname: Tatsumi
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D003971:Diastole; D004195:Disease Models, Animal; D004452:Echocardiography; D004562:Electrocardiography; D006041:Goats; D006339:Heart Rate; D006353:Heart-Assist Devices / Q000009:adverse effects*; D006801:Humans; D008944:Mitral Valve Insufficiency / Q000601:surgery*; D013599:Systole; D016306:Vena Cava Filters; D018497:Ventricular Dysfunction, Right / Q000209:etiology*
keywords: Left ventricular assist device; Mitral regurgitation; Rotational speed modulation