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Exploring the link between cardiovascular reactivity and end-organ damage in African and Caucasian men: the SABPA
Hugo W Huisman1, Aletta E Schutte, Rudolph Schutte
1Hypertension in Africa Research Team, North-West University, Potchefstroom Campus, South Africa. Hugo.Huisman@nwu.ac.za
Insights
African men experience suppressed stroke volume (SV) and increased vascular resistance, potentially leading to heart failure. These findings highlight the impact of afterload on cardiovascular health in this population.
Area of Science:
- Cardiovascular Physiology
- Vascular Biology
- Racial Health Disparities
Background:
- Heart failure prevalence is rising in African populations.
- Increased vasoconstriction during stress may impair cardiac function and lead to vascular changes.
- Investigating alpha-adrenergic vasoconstriction's role in cardiovascular health disparities is crucial.
Purpose of the Study:
- To compare cardiovascular responses to stress in African and Caucasian men.
- To evaluate the association between vascular resistance, stroke volume reactivity, and indicators of end-organ damage (left ventricular mass, carotid intima-media thickness).
Main Methods:
- 101 African and 101 Caucasian men underwent ambulatory blood pressure monitoring.
- Finometer and electrocardiogram were used to assess vascular resistance, stroke volume, and left ventricular mass (Cornell product).
- Carotid intima-media thickness (CIMT) and cross-sectional wall area (CSWA) were measured during the Stroop color word conflict test.
Main Results:
- African men exhibited higher resting vascular resistance and reactivity compared to Caucasian men.
- Stroke volume decreased significantly during stress in African men, with increased blood pressure and left ventricular mass.
- Stroke volume was inversely associated with left ventricular mass and CSWA in African men, but not in Caucasian men.
Conclusions:
- African men demonstrated suppressed stroke volume, likely due to increased ventricular afterload.
- This increased afterload may contribute to end-organ damage observed in African men.
- Findings suggest a potential mechanism for increased heart failure risk in the African population.
Background:
Heart failure in the African population is reaching alarming levels. Increased afterload as a result of increased vasoconstriction during stress may lead to impaired ventricular function and stroke volume (SV) as well as vascular hypertrophy. In this study, we challenged the cardiovascular system in order to evaluate the possible contribution of indicators of α-adrenergic vasoconstriction (i.e., vascular resistance and SV reactivity) on left ventricular mass and carotid intima-media thickness (CIMT) in African and Caucasian men.
Methods:
We evaluated 101 African and 101 Caucasian male schoolteachers. Ambulatory blood pressure measurements were taken. Total peripheral resistance, Windkessel compliance and SV, and resting and reactivity values were obtained using a Finometer device while the Stroop color word conflict test was being applied. The electrocardiogram was recorded to obtain the Cornell product as indication of left ventricular mass. The CIMT was measured and the cross-sectional wall area (CSWA) calculated.
Results:
African men showed higher total vascular resistance resting values as well as higher positive reactivity values compared with Caucasian men. The SV decreased significantly during stress in African men while resting blood pressure and the Cornell product value increased. SV showed a consistent association with left ventricular mass (β = -0.21; P = 0.04) and CSWA (β = -0.24; P = 0.01) in single and multiple regression analyses. No such associations were evident in the Caucasian men.
Conclusions:
African men showed a suppressed SV, possibly as a result of an increased ventricular afterload leading to end-organ damage.
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