Out-of-Clinic Sympathetic Activity Is Increased in Patients With Masked Uncontrolled Hypertension

Abstract

Masked uncontrolled hypertension (MUCH) is defined as controlled automated office BP (AOBP <135/85 mmHg) in clinic in patients receiving antihypertensive medication(s), but uncontrolled BP out-of-clinic by 24-hour ambulatory blood pressure monitoring (ABPM; awake ≥135/85 mmHg).We hypothesized that MUCH patients have greater out-of-clinic sympathetic activity compared to true controlled hypertensives. Patients being treated for hypertension were prospectively recruited after three or more consecutive clinic visits. All patients were evaluated by in-clinic AOBP, plasma catecholamines and spot-urine/plasma metanephrines. In addition, out-of-clinic 24-hr ABPM, 24-hr urinary for catecholamines and metanephrines was done. Out of 237 patients recruited, 169 patients had controlled in-clinic BP of which 156 patients had completed ABPM. Seventy-four were true controlled hypertensives, i.e. controlled by clinic AOBP and by out-of-clinic ABPM. The remaining 82 were controlled by clinic AOBP, but uncontrolled during out-of-clinic ABPM, indicative of MUCH. After exclusion of 4 patients because of inadequate or lack of 24-hr urinary collections, 72 true controlled hypertensive and 80 MUCH patients were analyzed. MUCH patients had significantly higher out-of-clinic BP variability and lower heart rate variability compared to true controlled hypertensives as well as higher levels of out-of-clinic urinary catecholamines and metanephrines levels consistent with higher out-of-clinic sympathetic activity. In contrast, there was no difference in in-clinic plasma catecholamines and spot-urine/plasma levels of metanephrines between the two groups, consistent with similar levels of sympathetic activity while in clinic. MUCH patients have evidence of heightened out-of-clinic sympathetic activity compared to true controlled hypertensives, which may contribute to the development of MUCH.

Sex difference in sympathetic nervous system activity and blood pressure in hypertensive patients

“…A meta‐analysis showed that HR was inversely correlated with MSNA, 7 which might be due to the combined effects of both sympathetic drive and vagal influences on the sinus node. A recent study demonstrated that patients with masked uncontrolled hypertension had higher out‐of‐clinic SNS activity than patients with controlled hypertension; patients with masked uncontrolled hypertension had similar 24‐h HR, awake HR, and asleep HR when compared to patients with controlled hypertension 8 . In the present study, men had higher ambulatory BP but similar 24‐h HR and awake HR than women in the total cohort.…”

“…7 Increased out-of-clinic SNS activity is also noted in patients with masked uncontrolled hypertension. 8 For hypertension management, it is important to clarify the impacts of SNS activity on blood pressure (BP) in different hypertension populations. There are well-described differences in CVD clinical manifestations, management, and outcomes between men and women.…”

Office blood pressure measurement: A comprehensive review

“…In the study by Siddiqui et al, it was found that patients with MUCH had evidence of heightened out-ofclinic sympathetic activity compared with true controlled hypertensive patients. 15 Problems with OBP measurements have led to the development of various devices and methodologies that have proven to give more accurate BP measurements. This includes the HBPM device which is used by the patient at home over a period of days or weeks and the ABPM device which is usually applied for 24 h and is preprogrammed to take measurements at set intervals.…”

Current status of ambulatory blood pressure monitoring in Asian countries: A report from the HOPE Asia Network

“…This indicates that out‐of‐office BP measurement during antihypertensive medication or titration to the target BP is also important. In recent studies, masked hypertension and MUCH, regardless of ABPM or HBPM, showed adverse prognoses, and MUCH diagnosed via ABPM is associated with increased sympathetic activities . In a recent study on ABPM, MUCH diagnosed on the basis of nocturnal BP is twofold more prevalent than MUCH diagnosed on the basis of daytime BP .…”