Circadian variation of blood pressure: clinical relevance and implications for cardiovascular chronotherapeutics

Area of Science:

• Cardiology
• Chronobiology
• Pharmacology

Background:

• Hemodynamic variability, influenced by the awake-sleep cycle, impacts cardiovascular disease outcomes.
• Increased blood pressure variability is linked to hypertensive target-organ damage.
• Epidemiologic studies show excess cardiac events (myocardial ischemia, infarction, sudden death) and cerebrovascular events (stroke) in early morning hours.

Purpose of the Study:

• To explore the pathophysiologic bases for increased cardiovascular events in the early morning.
• To review therapeutic strategies for antihypertensive and anti-ischemic therapies targeting morning blood pressure surges.
• To highlight cardiovascular chronotherapy as a future direction for optimizing drug delivery based on disease activity.

Main Methods:

• Review of existing epidemiologic and therapeutic studies on cardiovascular events and chronotherapy.
• Analysis of hemodynamic and rheologic factors contributing to morning cardiovascular events.
• Evaluation of studies on antihypertensive and anti-ischemic therapies with different dosing times.

Main Results:

• Significant excess incidence of myocardial ischemia, infarction, sudden cardiac death, and stroke observed in the early morning hours.
• Pathophysiologic bases for morning events are attributed to both hemodynamic and rheologic factors.
• Current studies on night-time dosing of conventional therapies are often underpowered to show significant differences in early morning blood pressure control.

Conclusions:

• Cardiovascular chronotherapy, by timing drug delivery to periods of enhanced disease activity, represents a promising future direction.
• Optimizing medication delivery based on inherent diurnal variability can improve therapeutic efficacy for cardiovascular diseases.
• Further research is needed to adequately power studies comparing morning versus evening dosing strategies.