Comparison between brachial blood pressures obtained by aneroid sphygmomanometer and central aortic pressures: factors affecting the measurements

OBJECTIVES
We compared brachial artery blood pressures (BP) measured by aneroid sphygmomanometer with ascending aortic blood pressures and evaluated the factors affecting the differences between the two methods.

STUDY DESIGN
The study included 463 patients (177 women, 286 men; mean age 60±11 years) undergoing routine coronary angiography. Simultaneously, ascending aortic pressures were measured using a pigtail catheter and brachial artery pressures were measured from the right arm with an aneroid sphygmomanometer. Pulse pressure, fractional pulse pressure, and pulsatility index were calculated from systolic and diastolic BP values.

RESULTS
Overall, systolic (-3.1±10 mmHg) and diastolic (+3.0±7.1 mmHg) brachial pressures showed significant deviations from aortic pressures (p=0.001). Although systolic BP did not differ significantly in both methods for men and women, brachial diastolic BP was significantly different in women (+4.8 mmHg, p=0.0001). Brachial diastolic BP showed a greater deviation from the aortic diastolic pressure in patients ≥60 years of age (+4.5 mmHg and +1.1 mmHg, respectively; p=0.0001). Deviation of systolic BP in hypertensive patients (-4 mmHg) was greater than that in normotensives (-2.0 mmHg, p=0.04). Deviation of brachial systolic BP was highly correlated with increases in aortic systolic pressure (p=0.0001). Differences between the two methods in systolic (-5.8 mmHg, p=0.01) and diastolic (+4.2 mmHg, p=0.03) BP were significant in patients with coexisting diabetes and hypertension. Body mass index and arm circumference were not correlated with deviations between the two methods.

CONCLUSION
The main factors (female gender, age, hypertension, diabetes) affecting BP differences between the two methods should be considered in clinical practice. Key words: Aorta; blood pressure; blood pressure determination/ methods; brachial artery; hypertension; sphygmomanometers.