Aims
Continuous‐flow left ventricular assist device (CF‐LVAD) implantation is associated with improved quality of life, but the effect on exercise capacity is less well documented. It is uncertain whether a fixed CF‐LVAD pump speed, which allows for sufficient circulatory support at rest, remains adequate during exercise. The aim of this study was to evaluate the effects of fixed versus incremental pump speed on peak oxygen uptake (peak VO2) during a maximal exercise test.
Methods and results
In CF‐LVAD (HeartMate II) patients exercise testing measuring peak oxygen uptake (VO2) was performed on an ergometer bike twice in one day: once with fixed pump speed (testfix) and once with incremental pump speed (testinc). The order of testfix and testinc in each patient was determined by randomization. During testinc pump speed was increased from the baseline value by 400 rpm/2 min. Fourteen patients (aged 23–69 years) were included with a mean support duration of 465 ± 483 days. Baseline CF‐LVAD speed was 9357 ± 238 rpm and during testinc speed was increased by a mean of 1486 ± 775 rpm. Mean peak VO2 was significantly higher in testinc compared with testfix (15.4 ± 5.9 mL/kg/min vs. 14.1 ± 6.3 mL/kg/min; P = 0.012), corresponding to a 9.2% increase. All exercise tests (n = 28) were adequately performed with RER > 1.
Conclusion
Increasing pump speed during exercise augments peak VO2 in patients supported with CF‐LVADs. An automatic speed‐change function in future generations of CF‐LVADs might improve functional capacity.
These results support the use of the HM II continuous-flow LVAD for long-term support as a bridge to transplantation and possibly for destination therapy. Future emphasis should focus on minimising adverse events such as infections, bleeding and neurological events.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.