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Sympathetic Overactivation in the Resistant Hypertensive Phenotype: A Meta-Analysis of Published Studies
Guido Grassi1, Fosca Quarti-Trevano1,2, Cesare Cuspidi1,3
1Department of Medicine and Surgery, University Milano-Bicocca, Italy (G.G., F.Q.-T., C.C., G.M.).
Hypertension (Dallas, Tex. : 1979)
|June 18, 2025
Summary
Drug-resistant hypertension (RHT) shows significantly higher sympathetic nerve activity compared to non-resistant hypertension. Standard markers like heart rate and norepinephrine do not reflect this increased adrenergic overdrive in RHT patients.
Area of Science:
- Cardiovascular Physiology
- Hypertension Research
- Neuroscience
Background:
- Essential hypertension patients responsive to treatment exhibit adrenergic overactivity.
- The sympathetic nervous system's role in drug-resistant hypertension (RHT) remains unclear.
- Investigating sympathetic activation in RHT is crucial for understanding its unique pathophysiology.
Purpose of the Study:
- To determine if RHT is characterized by sympathetic activation.
- To compare the magnitude and mechanisms of sympathetic activation in RHT versus non-RHT.
- To assess the utility of heart rate, norepinephrine, and baroreflex function as markers of sympathetic activity in RHT.
Main Methods:
- Meta-analysis of 12 studies (508 patients) investigating muscle sympathetic nerve traffic (MSNA) in RHT.
- Comparison of MSNA levels between RHT, non-RHT, and normotensive individuals.
- Evaluation of the relationship between MSNA, heart rate, plasma norepinephrine, and baroreflex function in RHT.
Main Results:
- MSNA was significantly elevated in RHT patients compared to both normotensive and non-RHT individuals.
- Elevated MSNA in RHT was not correlated with heart rate or plasma norepinephrine levels.
- Baroreflex function was inversely related to MSNA in RHT, similar to non-RHT.
Conclusions:
- RHT is defined by a pronounced and sustained sympathetic overdrive.
- The sympathetic activation in RHT is significantly greater than in non-RHT.
- Heart rate and norepinephrine are unreliable indicators of the heightened sympathetic activity in RHT.
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