Self-measurement of blood pressure (BP) is increasingly being used for the diagnosis of hypertension and to monitor BP at home. Whenever compared with ambulatory BP measurements, home BP values are frequently higher and less predictive for incident cardiovascular events. We hypothesized that this could be caused by a pressor response elicited by the self-measurement of BP.
A total of 50 patients (mean age 62.0 ± 11.2 years, 44% women) were included, 25 with and 25 without at least 10/5 mmHg higher home BP compared with daytime ambulatory BP. All patients performed 10 consecutive oscillometric BP measurements after 10 min of rest, followed by another resting period of 10 min, while continuously monitoring BP and central hemodynamics using finger photoplethysmography. Baseline BP before the start of the self-measurements was compared with the average BP during the first 10 s of inflation of the cuff.
In both groups, we observed a significant increase in SBP and DBP during cuff inflation. The mean rise in average BP was 6.9 ± 6.3/4.5 ± 4.3 mmHg in the group with and 4.4 ± 9.4/2.7 ± 5.3 mmHg in the group without a BP difference between home and daytime ambulatory BP compared with baseline, whereas the maximum increase in average BP was 17.4/8.4 mmHg and 17.7/7.5 mmHg (P < 0 01). The increase in BP coincided with an increase in heart rate and cardiac output. BP differences attenuated after multiple readings, but did not disappear.
Our results support the existence of a pressor response during self-BP measurement that remains present after multiple BP readings.