Inter-operator Reliability for Measuring Pulse Wave Velocity and Augmentation Index.

Arterial stiffness is a reversible precursor to hypertension. However, research is needed to determine the minimum amount of training required before acceptable arterial stiffness measurements are collected by novice operators. To compare novice vs. experienced operator measurements over a 2-week training period to assess when expert-like measures are achieved by the novice operator. Forty-one participants (18 males, 23 females, age: 46.6 ± 14.9 years; BMI: 25.2 ± 3.8; systolic blood pressure: 122.8 ± 14.7 mmHg) received alternating novice and experienced operator arterial stiffness assessments. Measurements included: pulse wave velocity (PWV; using the automatic-capture time-periods of 5-, 10-, and 20-s) and augmentation index (AIx75) measurements using the SphygmoCor XCEL System v1 (AtCor Medical Pty Ltd., Sydney, Australia). Data were chronologically arranged into quintiles. The intraclass correlation coefficient for PWV substantially improved from quintile 1 ( < 0.8) to quintile 2 and beyond (typically > 0.8) while AIx75 improved consistently ( = 0.7 in quintile 1 and r = 0.97 in quintile 5). The coefficient of variation was lowest in quintile 4 (PWV: 4.7-6% across the three measurement time-periods; and 15% for AIx75) but increased in quintile 5 (PWV: 6.2-10.5%; and 25% for AIx75). All measurements demonstrated acceptable to excellent reliability after quintile 2. To achieve expert-like PWV measurements in this study, the novice operator underwent a familiarization session including guided practice measurements on 5 different people, for 10-15 min per person on two occasions (~2.5 h). The novice operator then required ≥14 practice measurements, with accuracy continuing to improve up to 30 participants. At least 30 training measurements are recommended for novices to take acceptable AIx75 measurements after a familiarization training.