Validation of an oscillometric home blood pressure monitor in an end-stage renal disease population and the effect of arterial stiffness on its accuracy.

OBJECTIVES: Increased arterial stiffness, common in end-stage renal disease patients, has been shown to affect the correspondence between oscillometric and mercury sphygmomanometer blood pressure readings. The purpose of this study was to validate an oscillometric home blood pressure monitor in an end-stage renal disease population and to determine the effect of arterial stiffness on its accuracy.
METHODS: Blood pressure measurements were taken with the Microlife 3AC1-1PC (Microlife; Taipei, Taiwan), an oscillometric home blood pressure monitor, and a mercury sphygmomanometer in 33 patients as specified by the European Society of Hypertension Validation Protocol. Radial pulse wave analyses were also performed.
RESULTS: On the basis of European Society of Hypertension criteria, the Microlife 3AC1-1PC received a passing score for systolic and diastolic blood pressures. On average, the oscillometric monitor overestimated diastolic blood pressure by 2.4 mmHg (P=0.005, SD=4.5 mmHg) and there was a trend towards overestimation of systolic blood pressure as well (1.3 mmHg, P=0.09, SD=4.4 mmHg). A positive correlation was found between arterial stiffness, as assessed by augmentation index and pulse pressure, and the diastolic blood pressure difference between the device and the mercury sphygmomanometer (r=0.54, P=0.003; and r=0.65, P=0.001, respectively). Diastolic blood pressure was negatively correlated with the diastolic blood pressure difference (r=-0.49, P=0.003). No significant relationship was found between the systolic blood pressure difference and augmentation index, pulse pressure or systolic blood pressure.
CONCLUSION: The Microlife 3AC1-1PC was shown to accurately measure blood pressure in patients with end-stage renal disease. As arterial stiffness increased and diastolic blood pressure fell, diastolic blood pressure was increasingly overestimated.