Reproducibility and assessment of longitudinal confounders in the measurement of maternal haemodynamics in women with chronic hypertension in pregnancy

INTRODUCTION: To assess the reproducibility of Tensiomed Arteriograph measurements taken as part of a longitudinal cohort study of women with chronic hypertension (CHT).

METHODS/RESULTS: chartPulse wave velocity (PWV) and augmentation index (AIX) were measured three times (lying and sitting) per visit at 4-8 weekly intervals from 10 to 34 weeks gestation. Three hundred and ninety-one observations were available from 40 women. PWV and AIX were obtained in 95.4% and 94.6% of attempts. Intraclass coefficients (ICC) were calculated across six gestation windows. The median PWV ICC was 0.71 (range 0.22-0.92), improving to 0.84 (0.78-0.88) for readings with standard deviation <1.5m/s (79.6% of readings). Corresponding AIX ICCs were 0.88 (0.54-0.93) and 0.94 (0.92-0.97). For lying and sitting position measurements, PWV ICC was 0.82 (0.71-0.89) and AIX 0.81 (0.57-0.87). A 10 beat increase in HR was associated with 4.1-5.2% decrease in AIX, adjustment for HR reduced the gestational effect ( Figure 1 ). The effects of HR and gestation on PWV were smaller, but statistically significant. [Figure: see text] Discussion: PWV and AIX have acceptable reproducibility for use in clinical practice. Changes AIX attributable to HR are consistent with non-pregnant studies and interact with the gestational effect. Reproducibility was unaffected by maternal position, but unacceptable in 20% of readings and additional measures of haemodynamic status may therefore be required.