Improved left ventricular unloading and circulatory support with synchronized pulsatile left ventricular assistance compared with continuous-flow left ventricular assistance in an acute porcine left ventricular failure model.

Controversy exists regarding the optimal pumping method for left ventricular assist devices. The purpose of this investigation was to test the hypothesis that pulsatile left ventricular assist synchronized to the cardiac cycle provides superior left ventricular unloading and circulatory support compared with continuous-flow left ventricular assist devices at the same level of ventricular assist device flow. Seven male pigs were used to evaluate left ventricular assist device function using the TORVAD synchronized pulsatile-flow pump (Windmill Cardiovascular Systems, Inc, Austin, Tex) compared with the Bio-Medicus BPX-80 continuous-flow centrifugal pump (Medtronic, Inc, Minneapolis, Minn). Experiments were carried out under general anesthesia, and animals were instrumented via a median sternotomy. Hemodynamic measurements were obtained in the control state and with left ventricular assistance using the TORVAD and BPX-80 individually. Left ventricular failure was induced with suture ligation of the mid-left anterior descending coronary artery, and hemodynamic measurements were repeated. During left ventricular assist device support, mean aortic pressure and total cardiac output were higher and left atrial pressure was lower with pulsatile compared with continuous flow at the same ventricular assist device flow rate. During ischemic left ventricular failure, pulsatile left ventricular support resulted in higher total cardiac output (5.58 ± 1.58 vs 5.12 ± 1.19, P < .05), higher mean aortic pressure (67.8 ± 14 vs 60.2 ± 10, P < .05), and lower left atrial pressure (11.5 ± 3.5 vs 13.9 ± 6.0, P < .05) compared with continuous flow at the same left ventricular assist device flow rate. Synchronized, pulsatile left ventricular assistance produces superior left ventricular unloading and circulatory support compared with continuous-flow left ventricular assist at the same flow rates.

Letsou GV ，Pate TD ，Gohean JR ，Kurusz M ，Longoria RG ，Kaiser L ，Smalling RW ... -  《-》

Hemodynamic responses to continuous versus pulsatile mechanical unloading of the failing left ventricle.

Bartoli CR ，Giridharan GA ，Litwak KN ，Sobieski M ，Prabhu SD ，Slaughter MS ，Koenig SC ... -  《-》

Evaluation of a pulsatile pediatric ventricular assist device in an acute right heart failure model.

Shum-Tim D ，Duncan BW ，Hraska V ，Friehs I ，Shin'oka T ，Jonas RA ... -  《ANNALS OF THORACIC SURGERY》

Durability of left ventricular assist devices: Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) 2006 to 2011.

The present study compared the interval until device exchange or death from pump-related failure in patients with pulsatile versus continuous flow left ventricular assist devices. Data from Interagency Registry for Mechanically Assisted Circulatory Support (June 23, 2006, to March 31, 2011) compared the durability of implanted pulsatile and continuous flow left ventricular assist devices. The durability issues included pump replacement for infection, thrombosis-hemolysis, driveline failure, or pump drive unit failure, and death from driveline or pump drive unit failure. A total of 3302 left ventricular assist devices were implanted (486 pulsatile, 2816 continuous flow) and 98 pump exchanges or deaths from durability issues (46 pulsatile, 52 continuous flow; 3% of implants). The interval to device issue was greater for the continuous flow than for the pulsatile devices (P < .001). A comparisons of the causes for pump exchange or pump-related death showed (1) greater freedom from pump failure in the continuous flow compared with the pulsatile left ventricular assist devices (10 events/2816 continuous flow implants vs 39 events/486 pulsatile implants; P < .0001); (2) similar exchange or pump-related death for driveline failure (1/486 pulsatile vs 7/2816 continuous flow; P = .82); (3) similar exchange or pump-related death for thrombosis-hemolysis (2/486 pulsatile vs 28/2816 continuous flow; P = .25); and (4) fewer exchanges or pump-related deaths from infection in continuous flow left ventricular assist devices (4/486 pulsatile vs 7/2816 continuous flow; P = .034). Competing outcomes analysis corroborated this finding, with 54% of continuous flow versus 23% of pulsatile patients alive and receiving support at 12 months after implantation. The Analysis of Interagency Registry for Mechanically Assisted Circulatory Support data showed greater durability for continuous flow than for pulsatile left ventricular assist devices. Even longer durations of support can be expected if pump durability continues to improve.

Holman WL ，Naftel DC ，Eckert CE ，Kormos RL ，Goldstein DJ ，Kirklin JK ... -  《-》

Effects of pulsatile- and continuous-flow left ventricular assist devices on left ventricular unloading.

Garcia S ，Kandar F ，Boyle A ，Colvin-Adams M ，Lliao K ，Joyce L ，John R ... -  《-》