| Description |
Many aspects of cardiovascular disease (CVD) are preceded by an attenuation of the ability to adjust vascular tone appropriately, termed arterial vascular function. Thus, utilizing simple noninvasive measures of arterial vascular functions provides an assessment of vascular health, risk of CVD and insight into adverse events from medical therapies. The first, of three studies, focuses on honing a vascular function-screening tool, while the second of two studies investigates restorative interventions of arterial vascular health in advanced heart failure patients implanted with a left ventricular assist device (LVAD). In study 1, the more refined version of the passive leg movement vascular function test that utilizes a single movement rather than 60 (sPLM) demonstrated the prerequisite qualities of a valid screening test. The primary measure, total leg blood flow above baseline for 45 seconds after the start of the movement (AUC 45s) was attenuated in the old (Young: 155 ± 67, Old: 26 ± 17 ml, P < 0.001; cut score: 58 ml). In study 2, vascular function, assessed by flow mediated dilation normalized by sum of shear to peak dilation (%FMD/Shear), improved as a result of a 45-minute pulsatility treatment, providing key evidence for a causal link between arterial pulsatility and arterial vascular function. Before the intervention, %FMD/Shear was different between two cohorts of diverse arterial pulsatility (LVAD: 0.10±0.01; Controls: 0.17±0.02 %/s-1), which improved as a result of the pulsatility treatment (LVAD: 0.19±0.02; Controls 0.33±0.04 %/s-1). In study 3, the reduction in LVAD pump speed (revolutions per minute, rpm) improved arterial pulsatility iv in both the HeartWare Ventricular Assist Device (HVAD) (-180 rpm: 37±4 %) and HeartMate II (-600 rpm: 38 ± 3 %). sPLM identified an age-related reduction in arterial vascular function with well-delineated age-specific cut scores, demonstrating the potential ability to be a surrogate for more complex vascular function tests. The pulsatility treatment restored vascular function in the LVAD recipients to the pretreatment level of the controls, providing key evidence for a causal link between pulsatility and vascular health. Lastly, LVAD rpm reductions, within a clinical outpatient range, increased systemic pulsatility, validating the intervention to potentially improve vascular health and LVAD outcomes. |
