The hemodynamics in young patients with borderline hypertension
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Borderline hypertension involves abnormal total peripheral resistance (TPR) and potentially impaired neurogenic activity. Some patients show a hyperkinetic state with increased cardiac index (CI) and plasma renin activity (PRA).
Area of Science:
- Cardiovascular Physiology
- Hypertension Research
- Neurogenic Regulation
Background:
- Borderline hypertension represents an early stage of essential hypertension.
- Understanding hemodynamic alterations and neurogenic contributions is crucial for early intervention.
Purpose of the Study:
- To investigate hemodynamic differences in young patients with borderline hypertension compared to normotensive controls.
- To explore the role of neurogenic activity and plasma renin activity (PRA) in different hemodynamic profiles of borderline hypertension.
Main Methods:
- Echocardiography was used to assess hemodynamic parameters in 56 young patients with borderline hypertension and 56 age-matched normotensive subjects in a supine position.
- Patients with borderline hypertension were categorized into two groups based on cardiac index (CI): Group A (normal CI) and Group B (high CI).
- Measurements included cardiac index (CI), total peripheral resistance (TPR), heart rate, mean circumferential fiber shortening velocity (mVCF), and plasma renin activity (PRA).
Main Results:
- Hypertensive patients exhibited a non-increasing CI but a significant increase in total peripheral resistance (TPR).
- Group A showed normal CI, heart rate, and mVCF, but significantly increased TPR.
- Group B displayed significantly increased CI, heart rate, and mVCF (hyperkinetic state) with normal TPR. PRA was elevated in Group B compared to controls, and normal in Group A.
Conclusions:
- Total peripheral resistance (TPR) is abnormal in borderline hypertension.
- Impaired neurogenic activity may play a significant role in the early stages of hypertension.
- Borderline hypertension can present with a hyperkinetic circulatory state, associated with increased sympathetic nervous activity and PRA.
Abstract:
Hemodynamics in supine position were studied echocardiographically in 56 young patients with borderline hypertension and 56 age-matched normotensive subjects. In hypertensive patients, the cardiac index (CI) did not increase, but the total peripheral resistance (TPR) increased significantly (p less than 0.005). The hypertensive patients were classified into 2 groups, according to the level of the CI. In patients in group A ("normal" CI), the CI, heart rate and the mean circumferential fiber shortening velocity (mVCF) were normal, but the TPR was increased significantly. In patients in group B ("high" CI), the CI, heart rate and the mVCF increased significantly (hyperkinetic state), but the TPR was normal. Plasma renin activity (PRA) was significantly higher in patients in group B than the normal subjects, but the level of PRA in patients in group A was normal. These findings support the hypothesis that sympathetic nervous activity increases in patients in group B, but not in those in group A. Therefore, this study provides evidence that the TPR is abnormal in patients with borderline hypertension, and an impaired neurogenic activity seems to be important in the early stage of hypertension, as in borderline hypertension associated with a hyperkinetic circulatory state (group B).