Test re-test reliability and minimal detectable change of pulse wave velocity and flow mediated dilation in paretic and non-paretic limbs of older adults post-stroke

Arterial stiffness and endothelial dysfunction are non-traditional risk markers after stroke, yet reliability and minimal detectable change (MDC) of pulse wave velocity (PWV) and flow-mediated dilation (FMD) have not been established. We examined test-retest reliability and MDC of carotid-femoral (cfPWV), carotid-radial (crPWV), and femoral-dorsalis pedis PWV (ffPWV), and absolute and relative brachial artery FMD in people >12 months post-stroke. Seventeen individuals (n=4(24%) females; 63.9{+/-}8.6 years; 4.5{+/-}2.8 years post-stroke) completed two bilateral assessments of PWV via applanation tonometry and FMD via duplex ultrasound within one week. Intraclass correlation coefficients (ICC2,1) were calculated via two-way random-effects models, and MDC derived at 68%, 90%, and 95% confidence levels. We found good-to-excellent reliability for cfPWV in paretic (ICC2,1=0.85; 95%CI:0.59,0.95) and non-paretic (ICC2,1=0.94; 95%CI:0.82,0.98) limbs, with MDC95% values of 2.23 and 1.68 m/s, respectively. crPWV and ffPWV exhibited poor reliability bilaterally (ICC2,1=0.12-0.33). Relative FMD showed-moderate reliability for paretic (ICC2,1=0.50; 95%CI:-0.20,0.85) and non-paretic (ICC=0.59; 95%CI:0.04,0.84) limbs, with MDC95% values of 6.88% and 7.65%, respectively. Reliability for absolute FMD was poor (ICC2,1=0.11-0.44). These findings support cfPWV as a reliable vascular assessments in individuals >12 months post-stroke, and provide stroke-specific MDC values to guide interpretability in future trials.