P38 DIFFERENCES IN FORM FACTOR CALCULATED FROM OSCILLOMETRIC OR WAVEFORM MEAN ARTERIAL PRESSURE

DOI

10.1016/j.artres.2018.10.091How to use a DOI?

Abstract

Background: Oscillometric mean arterial pressure (MAP) agrees closely with invasive MAP, [1] but most devices do not report MAP and it is usually estimated by a form factor (FF). However, blood pressure (BP) measurement errors will affect FF, its correlations with exposures, and introduce errors into MAP estimated from the BP waveform.

Methods: Brachial BP was measured using a Pulsecor device in 1,112 participants in the Southall and Brent Revisited study (68.8 ± 6.1 y; 78.2% male; 47.4% White-European; 38.3% South-Asian; 14.3% African-Caribbean). Form factors (FFosc and FFwave) were calculated as (MAP-diastolic BP)/(systolic BP-diastolic BP) by oscillometry (MAPosc) or from the BP waveform (MAPwave).

Results: FFosc and FFwave differed (0.28 (SD = 0.02) vs. 0.36 (SD = 0.04); p <0.001) and were negligibly correlated (r = 0.07). Neither FF_osc nor FF_wave were associated with ethnicity, prevalent cardiovascular disease or current smoking status, and neither showed significant correlations with age, total- or HDL-cholesterol, or physical activity. Both FF_osc and FF_wave were lower in men (difference (Δ) = −0.005(95% CI = −0.007, −0.002) vs −0.015(95% CI = −0.020, 0.009) respectively) and were negatively correlated with height (r = −0.14 both), but only FF_wave correlated with body mass index (r = 0.02 vs r = 0.10) and heart rate (r = −0.06 vs r = 0.20). ΔMAP_osc-MAP_wave correlated with age (r = 0.10), height (r=0.15) and heart rate (0.17) and was greater in women (0.9(95% CI = 0.5, 1.3) mmHg).

Conclusions: FF_wave agrees poorly with FF_osc probably due to measurement errors. This creates spurious associations between exposures and FF and causes systematic errors in estimated MAP_wave. These errors have the potential to confound associations in epidemiological studies.

Open Access

This is an open access article distributed under the CC BY-NC license.

Download article (PDF)
View full text (HTML)

TY  - JOUR
AU  - Chloe Park
AU  - Therese Tillin
AU  - Nish Chaturvedi
AU  - Alun Hughes
PY  - 2018
DA  - 2018/12/04
TI  - P38 DIFFERENCES IN FORM FACTOR CALCULATED FROM OSCILLOMETRIC OR WAVEFORM MEAN ARTERIAL PRESSURE
JO  - Artery Research
SP  - 90
EP  - 90
VL  - 24
IS  - C
SN  - 1876-4401
UR  - https://doi.org/10.1016/j.artres.2018.10.091
DO  - 10.1016/j.artres.2018.10.091
ID  - Park2018
ER  -