Central and peripheral blood flow during exercise with a continuous-flow left ventricular assist device: constant versus increasing pump speed: a pilot study

TY - JOUR

T1 - Central and peripheral blood flow during exercise with a continuous-flow left ventricular assist device: constant versus increasing pump speed: a pilot study

AU - Brassard, Patrice

AU - Jensen, Annette S

AU - Nordsborg, Nikolai

AU - Gustafsson, Finn

AU - Møller, Jacob E

AU - Hassager, Christian

AU - Boesgaard, Søren

AU - Hansen, Peter Bo

AU - Olsen, Peter Skov

AU - Sander, Kåre

AU - Secher, Niels H

AU - Madsen, Per Lav

N1 - CURIS 2011 5200 091

PY - 2011/9

Y1 - 2011/9

N2 - Background: End-stage heart failure is associated with impaired cardiac output (CO) and organ blood flow. We determined whether CO and peripheral perfusion are maintained during exercise in patients with an axial-flow left ventricular assist device (LVAD) and whether an increase in LVAD pump speed with work rate would increase organ blood flow. Methods and Results: Invasively determined CO and leg blood flow and Doppler-determined cerebral perfusion were measured during 2 incremental cycle exercise tests on the same day in 8 patients provided with a HeartMate II LVAD. In random order, patients exercised both with a constant (≈9775 rpm) and with an increasing pump speed (+400 rpm per exercise stage). At 60 W, the elevation in CO was more pronounced with increased pump speed (8.7±0.6 versus 8.1 ± 1.1 L·min -1; mean±SD; P=0.05), but at maximal exercise increases in CO (from 7.0±0.9 to 13.6±2.5 L · min -1; P<0.01) and leg blood flow [0.7 (0.5 to 0.8) to 4.4 (3.9 to 4.8) L · min -1 per leg; median (range); P<0.001] were similar with both pumping modes. Normally, middle cerebral artery mean flow velocity increases from ≈50 to ≈65 cm · s -1 during exercise, but in LVAD patients with a constant pump speed it was low at rest (39±14 cm · s -1) and remained unchanged during exercise, whereas in patients with increasing pump speed, it increased by 5.2±2.8 cm · s -1 at 60 W (P<0.01). Conclusions: With maximal exercise, the axial-flow LVAD supports near-normal increments in cardiac output and leg perfusion, but cerebral perfusion is poor. Increased pump speed augments cerebral perfusion during exercise. (Circ

AB - Background: End-stage heart failure is associated with impaired cardiac output (CO) and organ blood flow. We determined whether CO and peripheral perfusion are maintained during exercise in patients with an axial-flow left ventricular assist device (LVAD) and whether an increase in LVAD pump speed with work rate would increase organ blood flow. Methods and Results: Invasively determined CO and leg blood flow and Doppler-determined cerebral perfusion were measured during 2 incremental cycle exercise tests on the same day in 8 patients provided with a HeartMate II LVAD. In random order, patients exercised both with a constant (≈9775 rpm) and with an increasing pump speed (+400 rpm per exercise stage). At 60 W, the elevation in CO was more pronounced with increased pump speed (8.7±0.6 versus 8.1 ± 1.1 L·min -1; mean±SD; P=0.05), but at maximal exercise increases in CO (from 7.0±0.9 to 13.6±2.5 L · min -1; P<0.01) and leg blood flow [0.7 (0.5 to 0.8) to 4.4 (3.9 to 4.8) L · min -1 per leg; median (range); P<0.001] were similar with both pumping modes. Normally, middle cerebral artery mean flow velocity increases from ≈50 to ≈65 cm · s -1 during exercise, but in LVAD patients with a constant pump speed it was low at rest (39±14 cm · s -1) and remained unchanged during exercise, whereas in patients with increasing pump speed, it increased by 5.2±2.8 cm · s -1 at 60 W (P<0.01). Conclusions: With maximal exercise, the axial-flow LVAD supports near-normal increments in cardiac output and leg perfusion, but cerebral perfusion is poor. Increased pump speed augments cerebral perfusion during exercise. (Circ

U2 - 10.1161/CIRCHEARTFAILURE.110.958041

DO - 10.1161/CIRCHEARTFAILURE.110.958041

M3 - Journal article

C2 - 21765126

SN - 1941-3289

VL - 4

SP - 554

EP - 560

JO - Circulation: Heart Failure

JF - Circulation: Heart Failure

IS - 5

ER -