title: Development of a novel echocardiography ramp test for speed optimization and diagnosis of device thrombosis in continuous-flow left ventricular assist devices: the Columbia ramp study.
abstract: OBJECTIVE
  This study sought to develop a novel approach to optimizing continuous-flow left ventricular assist device (CF-LVAD) function and diagnosing device malfunctions.
  
  
  BACKGROUND
  In CF-LVAD patients, the dynamic interaction of device speed, left and right ventricular decompression, and valve function can be assessed during an echocardiography-monitored speed ramp test.
  
  
  METHODS
  We devised a unique ramp test protocol to be routinely used at the time of discharge for speed optimization and/or if device malfunction was suspected. The patient's left ventricular end-diastolic dimension, frequency of aortic valve opening, valvular insufficiency, blood pressure, and CF-LVAD parameters were recorded in increments of 400 rpm from 8,000 rpm to 12,000 rpm. The results of the speed designations were plotted, and linear function slopes for left ventricular end-diastolic dimension, pulsatility index, and power were calculated.
  
  
  RESULTS
  Fifty-two ramp tests for 39 patients were prospectively collected and analyzed. Twenty-eight ramp tests were performed for speed optimization, and speed was changed in 17 (61%) with a mean absolute value adjustment of 424 ± 211 rpm. Seventeen patients had ramp tests performed for suspected device thrombosis, and 10 tests were suspicious for device thrombosis; these patients were then treated with intensified anticoagulation and/or device exchange/emergent transplantation. Device thrombosis was confirmed in 8 of 10 cases at the time of emergent device exchange or transplantation. All patients with device thrombosis, but none of the remaining patients had a left ventricular end-diastolic dimension slope >-0.16.
  
  
  CONCLUSIONS
  Ramp tests facilitate optimal speed changes and device malfunction detection and may be used to monitor the effects of therapeutic interventions and need for surgical intervention in CF-LVAD patients.
authors.affiliation: Division of Cardiology, Department of Medicine, Columbia University Medical Center, New York, New York 10032, USA. urielnir@gmail.com
authors.forename: Nir
authors.initials: N
authors.lastname: Uriel
authors.forename: Kerry A
authors.initials: KA
authors.lastname: Morrison
authors.forename: Arthur R
authors.initials: AR
authors.lastname: Garan
authors.forename: Tomoko S
authors.initials: TS
authors.lastname: Kato
authors.forename: Melana
authors.initials: M
authors.lastname: Yuzefpolskaya
authors.forename: Farhana
authors.initials: F
authors.lastname: Latif
authors.forename: Susan W
authors.initials: SW
authors.lastname: Restaino
authors.forename: Donna M
authors.initials: DM
authors.lastname: Mancini
authors.forename: Margaret
authors.initials: M
authors.lastname: Flannery
authors.forename: Hiroo
authors.initials: H
authors.lastname: Takayama
authors.forename: Ranjit
authors.initials: R
authors.lastname: John
authors.forename: Paolo C
authors.initials: PC
authors.lastname: Colombo
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Naka
authors.forename: Ulrich P
authors.initials: UP
authors.lastname: Jorde
mesh_terms: D000368:Aged; D062186:Arterial Pressure; D001794:Blood Pressure; D001795:Blood Pressure Determination; D002309:Cardiology / Q000379:methods; D015331:Cohort Studies; D004452:Echocardiography / Q000379:methods*; D005260:Female; D006353:Heart-Assist Devices / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D011446:Prospective Studies; D011475:Prosthesis Failure; D013927:Thrombosis / Q000175:diagnosis* / Q000628:therapy*; D016277:Ventricular Function, Left / Q000502:physiology