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Influence of arterial pulse and reflective waves on systolic blood pressure and cardiac function
1Cêntre Hospitalier FH Manhès, Fleury-Merogis, France.
Insights
Systolic blood pressure, not diastolic, is a better indicator of cardiovascular risk, especially for stroke and coronary artery disease in older adults. Arterial stiffness contributes to rising systolic pressure, creating a damaging cycle.
Area of Science:
- Cardiovascular Medicine
- Hypertension Research
- Arterial Physiology
Background:
- Hypertension is a major cardiovascular risk factor linked to reduced small artery calibre and increased peripheral vascular resistance.
- Traditional blood pressure definitions (TPR x Cardiac Output) don't fully capture cardiac cycle dynamics.
- Diastolic blood pressure, though closer to mean arterial pressure, is a less accurate hypertension marker than systolic pressure.
Purpose of the Study:
- To challenge the traditional diagnostic basis of hypertension.
- To highlight systolic blood pressure as a superior cardiovascular risk marker.
- To elucidate the mechanisms driving systolic blood pressure elevation in hypertension.
Main Methods:
- Review of epidemiological data, including the Framingham Heart Study.
- Analysis of interventional studies.
- Examination of physiological determinants of systolic blood pressure.
Main Results:
- Systolic blood pressure is a better predictor of stroke and coronary artery disease risk than diastolic blood pressure in individuals aged 45 and older.
- Systolic blood pressure is influenced by left ventricular ejection, arterial stiffness, and wave reflections.
- Arterial stiffening, due to medial degeneration and changes in collagen/calcium content, contributes to elevated systolic pressure.
Conclusions:
- Systolic blood pressure is a more critical marker for cardiovascular risk assessment.
- Ageing and hypertension lead to arterial stiffening, a self-perpetuating cycle of arterial damage.
- Understanding these mechanisms is crucial for effective hypertension management and cardiovascular disease prevention.
Abstract:
Hypertension is a cardiovascular risk factor classically attributed to a reduction in the calibre and/or number of small arteries and arterioles resulting in increased peripheral vascular resistance. The definition of blood pressure as a product of total peripheral resistance (TPR) and cardiac output, however, does not take into account the fluctuation of blood pressure and flow during the cardiac cycle, with systolic and diastolic blood pressure representing the extremes of pulse pressure fluctuations. Diastolic blood pressure is closer to mean blood pressure (and therefore to TPR) than systolic blood pressure, and as such has been used as a marker for the diagnosis of hypertension. However, this approach has no rational basis and was challenged by the Framingham Heart Study which demonstrated that systolic rather than diastolic blood pressure is a better risk marker for stroke and coronary artery disease in subjects aged 45 years and older. This view has subsequently been confirmed by several epidemiological and interventional studies. Systolic blood pressure is closely associated with pulse pressure and is determined by the pattern of left ventricular ejection, arterial stiffness and timing of arterial wave reflections, i.e. the geometrical and viscoelastic properties of large conduit arteries. In humans, with ageing and hypertension, the arteries stiffen as a result of progressive degeneration of the arterial media, increased collagen and calcium content, and dilation and hypertrophy of large arteries and the aorta. Thus, the increase in systolic blood pressure (as a result of arterial damage) increases the fatigue of arterial walls and accelerates arterial damage, producing a self-perpetuating cycle.