(Circulation. 2007;116:I-8 – I-15.)
© 2007 American Heart Association, Inc.
Cardiac Transplantation and Surgery for Heart Failure |
From the Section of Cardiac Surgery (J.H., F.D.P.) and the Division of Cardiovascular Medicine (W.A., D.B.D., K.D.A., T.M.K.), University of Michigan Health System, Ann Arbor, Mich; and Thoratec Corp (D.J.F.), Pleasanton, Calif.
Correspondence to Francis D. Pagani, MD, PhD, Associate Professor of Surgery, University of Michigan Health System, Cardiovascular Center, Rm 5161, 1500 East Medical Center Drive, SPC 5864, Ann Arbor, MI 48109-5864. E-mail fpagani{at}umich.edu
Background— Continuous-flow rotary pumps with axial design are increasingly used for left ventricular assist support. The efficacy of this design compared with pulsatile, volume displacement pumps, with respect to characteristics of left ventricular unloading, and exercise performance remains largely unstudied.
Methods and Results— Thirty-four patients undergoing implantation with a pulsatile, volume displacement pump operating in a full-to-empty cycle (HeartMate XVE; Thoratec Inc, Pleasanton, Calif; n=16) or continuous-flow rotary pump with an axial design operating at a fixed rotor speed (HeartMate II; Thoratec Inc; n=18) were evaluated with right heart catheterization and echocardiography preoperatively and at 3 months postoperatively and cardiopulmonary exercise testing 3 months postoperatively. Support with either the XVE or II resulted in significant (P<0.05) increases in cardiac output and reduction in mean pulmonary artery and pulmonary wedge pressures. Exercise capacity at 3 months was similar between groups (% predicted peak
O2–XVE: 46.8±10.2 versus II: 49.1±13.6). Echocardiography at 3 months demonstrated a significantly (P<0.05) greater reduction in left ventricular end-diastolic volume (–49±16% versus –35±20%), left ventricular end-systolic volume (–59±20 versus –37±21%), and percent mitral valve regurgitant volume (–99±2% versus –52±56%) for the XVE compared with II, respectively.
Conclusions— The HeartMate XVE or II provided equivalent degrees of hemodynamic support and exercise capacity. The XVE was associated with greater left ventricular volume unloading. Characteristics of left ventricular pressure and volume unloading between these pump designs and mode of operation do not influence early exercise performance.
Key Words: exercise heart failure hemodynamics surgery transplantation
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