title: Early elevations in pump power with the HeartMate II left ventricular assist device do not predict late adverse events.
abstract: BACKGROUND
  The aim of this study was to evaluate the prevalence of early pump power elevation events in patients with the HeartMate II (HMII) and its impact on subsequent development of stroke and pump thrombosis.
  
  
  METHODS
  We analyzed >45,000 measurements of pump power and pump speed measured during the initial hospitalization period and >12,000 follow-up measurements obtained from 138 consecutive patients implanted with a HMII between January 2009 and December 2012. An early power elevation (PEL) event was defined as power ≥10 W within the first 14 post-operative days. Patients were divided into two groups: those with an early PEL event and those without (NP).
  
  
  RESULTS
  Median follow-up duration was 316 (range 2 to 1,264) days. Twenty-seven (20%) patients had early PEL events that lasted for a total duration of 4 (range 1 to 77) hours per patient. Pump speed averaged 9,400 rpm in both groups. Although patients in the PEL group had higher median power (7.1 [6.0 to 9.9] W vs 6.7 [5.7 to 7.8] W, p < 0.001) in the immediate post-operative period, there was no difference between the two groups noted at first follow-up (6.6 [5.9 to 8.7] W vs 6.7 [5.5 to 7.7] W, p = 0.940). No differences in the prevalence of hemorrhagic stroke (4% vs 3%, p = 0.56), ischemic stroke (0% vs 4%, p = 0.41), hemolysis (7% vs 5%, p = 0.32), pump thrombosis (7% vs 4%, p = 0.21) or survival (76% at 1 year in both groups) were found between the two groups.
  
  
  CONCLUSIONS
  In this single-center experience, PEL events that occurred early all resolved by discharge. No relationship was found between early PEL events and subsequent development of pump thrombosis, hemorrhagic stroke or ischemic stroke.
authors.affiliation: Department of Cardiothoracic Surgery, St. Vincent Heart Center of Indiana, Indianapolis, Indiana. Electronic address: ctsalern@stvincent.org.
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Salerno
authors.affiliation: Research and Scientific Affairs, Thoratec Corporation, Pleasanton, California.
authors.forename: Kartik S
authors.initials: KS
authors.lastname: Sundareswaran
authors.affiliation: Department of Cardiology, St. Vincent Heart Center of Indiana, Indianapolis, Indiana, USA.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Schleeter
authors.affiliation: Department of Cardiothoracic Surgery, St. Vincent Heart Center of Indiana, Indianapolis, Indiana.
authors.forename: Sina L
authors.initials: SL
authors.lastname: Moanie
authors.affiliation: Research and Scientific Affairs, Thoratec Corporation, Pleasanton, California.
authors.forename: David J
authors.initials: DJ
authors.lastname: Farrar
authors.affiliation: Research and Scientific Affairs, Thoratec Corporation, Pleasanton, California.
authors.forename: Mary Norine
authors.initials: MN
authors.lastname: Walsh
mesh_terms: D000328:Adult; D000368:Aged; D011211:Electric Power Supplies / Q000009:adverse effects / Q000706:statistics & numerical data*; D004868:Equipment Failure / Q000706:statistics & numerical data*; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000628:therapy*; D006353:Heart-Assist Devices / Q000009:adverse effects / Q000706:statistics & numerical data*; D006461:Hemolysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology*; D013927:Thrombosis / Q000453:epidemiology*; D013997:Time Factors; D016896:Treatment Outcome
keywords: HMII; HeartMate II; LVAD; hemolysis; pump power; thrombus