P63 Accuracy (Validation) of Central Blood Pressure Measurement Using the Sphygmocor Xcel-cuff Device

Abstract

Background

Numerous devices purport to measure central aortic BP as distinct from conventional brachial BP. This study aimed to determine the accuracy (validation) of the Sphygmocor Xcel-cuff device (AtCor Medical, Sydney, Australia) for measuring central BP.

Methods

330 patients (mean age 61.3 ± 10.6 years) undergoing coronary angiography had simultaneous measurement of invasive aortic BP and non-invasive cuff-derived central BP using the Xcel device (total n = 552 individual comparisons). Methods were undertaken according to Artery Society guidelines and several calibration techniques to derive central SBP were examined.

Results

Central SBP was significantly underestimated, and with wide variability, when using the default calibration of brachial cuff SBP/DBP (−7.7 ± 11.0 mmHg). Similar wide variability was observed using other calibration methods (cuff 33% form-factor MAP/DBP, −4.4 ± 11.5 mmHg; cuff 40% form-factor MAP/DBP, 4.7 ± 11.9 mmHg; cuff oscillometric MAP/DBP, −18.2 ± 12.1 mmHg). Only calibration with invasive aortic integrated MAP/DBP resulted in a mean difference ± SD (3.3 ± 7.5 mmHg) within the minimum tolerable error of ≤5 ± ≤8 mmHg. The difference between brachial cuff SBP and invasive aortic SBP was 3.3 ± 10.7 mmHg. A subsample (n = 151) analysis to determine the accuracy of central-to-brachial SBP amplification, showed this to be over-estimated by the Xcel device (4.3 ± 9.1 mmHg, p = 0.02).

Conclusion

Irrespective of calibration technique, the Sphygmocor Xcel-cuff device does not pass the Artery Society accuracy (validation) criteria for non-invasive measurement of central BP. Further accuracy refinements of this device are required.