Muthiah, Kavitha and Robson, Desiree and Prichard, Roslyn and Walker, Robyn and Gupta, Sunil and Keogh, Anne M and Macdonald, Peter S and Woodard, John and Kotlyar, Eugene and Dhital, Kumud and Granger, Emily and Jansz, Paul and Spratt, Phillip and Hayward, Christopher S (2015) Effect of exercise and pump speed modulation on invasive hemodynamics in patients with centrifugal continuous-flow left ventricular assist devices. The Journal of Heart and Lung Transplantation, 34 (4). pp.522-9. ISSN 1557-3117 (N/A)
Full text not available from this repository.Abstract
BACKGROUND
Continuous-flow left ventricular assist devices (CF-LVADs) improve functional capacity in patients with end-stage heart failure. Pump output can be increased by increased pump speed as well as changes in loading conditions.
METHODS
The effect of exercise on invasive hemodynamics was studied in two study protocols. The first examined exercise at fixed pump speed (n = 8) and the second with progressive pump speed increase (n = 11). Patients underwent simultaneous right-heart catheterization, mixed venous saturation, echocardiography and mean arterial pressure monitoring. Before exercise, a ramp speed study was performed in all patients. Patients then undertook symptom-limited supine bicycle exercise.
RESULTS
Upward titration of pump speed at rest (by 11.6 ± 8.6% from baseline) increased pump flow from 5.3 ± 1.0 to 6.3 ± 1.0 liters/min (18.9% increase, p < 0.001) and decreased pulmonary capillary wedge pressure (PCWP; 13.6 ± 5.4 to 8.9 ± 4.1 mm Hg, p < 0.001). Exercise increased pump flow to a similar extent as pump speed change alone (to 6.2 ± 1.0 liters/min, p < 0.001), but resulted in increased right- and left-heart filling pressures (right atrial pressure [RAP]: 16.6 ± 7.5 mm Hg, p < 0.001; PCWP 24.8 ± 6.7 mm Hg, p < 0.001). Concomitant pump speed increase with exercise enhanced the pump flow increase (to 7.0 ± 1.4 liters/min, p < 0.001) in Protocol 2, but did not alleviate the increase in pre-load (RAP: 20.5 ± 8.0 mm Hg, p = 0.07; PCWP: 26.8 ± 12.7 mm Hg; p = 0.47). Serum lactate and NT-proBNP levels increased significantly with exercise.
CONCLUSIONS
Pump flow increases with up-titration of pump speed and with exercise. Although increased pump speed decreases filling pressures at rest, the benefit is not seen with exercise despite concurrent up-titration of pump speed.
| Item Type: | Article |
|---|---|
| Subjects: | R Medicine > R Medicine (General) |
| Depositing User: | Repository Administrator |
| Date Deposited: | 04 Feb 2016 03:43 |
| Last Modified: | 17 Jan 2018 08:21 |
| URI: | https://eprints.victorchang.edu.au/id/eprint/318 |
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