Which is more concerning, systolic or diastolic blood pressure?

Systolic Blood Pressure is More Worrying Than Diastolic Blood Pressure

Systolic blood pressure is generally more concerning than diastolic blood pressure, particularly in middle-aged and elderly individuals, as it is a stronger predictor of cardiovascular morbidity and mortality. 1, 2

Understanding Blood Pressure Components and Their Impact

• Both systolic and diastolic blood pressures have a continuous relationship with cardiovascular risk, but their relative importance varies with age 1
• In younger individuals (under 55 years), both systolic and diastolic pressures are independently and similarly predictive of stroke and coronary mortality 1
• As people age, systolic blood pressure becomes progressively more important as a risk predictor 1, 2
• For any given systolic level in elderly individuals, cardiovascular outcomes are inversely proportional to diastolic blood pressure (meaning a wider pulse pressure increases risk) 1

Age-Related Changes in Blood Pressure

• Systolic blood pressure increases progressively with age, while diastolic blood pressure tends to plateau or even decrease after middle age 1
• This age-related pattern leads to increased pulse pressure (systolic minus diastolic), which is particularly concerning in elderly patients 1, 3
• The increase in systolic pressure with age is primarily due to arterial stiffening, which reduces the elasticity of large arteries 4, 5

Clinical Significance in Risk Assessment

• In the largest meta-analysis of observational data (61 studies with almost 1 million subjects), both systolic and diastolic blood pressures were independently predictive of stroke and coronary mortality in people under 55 years 1
• In middle-aged and elderly patients with cardiovascular risk factors, pulse pressure showed a strong predictive value for cardiovascular events 1
• For every 20 mmHg systolic or 10 mmHg diastolic increase in blood pressure, there is a doubling of mortality from both ischemic heart disease and stroke 1

Coronary Perfusion Considerations

• Myocardial perfusion occurs almost exclusively during diastole, making diastolic blood pressure the primary coronary perfusion pressure 4
• Very low diastolic pressure (below 60-70 mmHg) in the presence of coronary artery disease may compromise coronary perfusion 1, 5
• This creates a clinical dilemma in treating isolated systolic hypertension in elderly patients, as aggressive treatment might lower diastolic pressure too much 5

Treatment Implications

• Classification of hypertension and risk assessment should continue to be based on both systolic and diastolic blood pressures 1
• When a patient's systolic and diastolic blood pressures fall into different categories, the higher category should apply for risk assessment and treatment decisions 1
• Isolated systolic hypertension should be treated according to the same systolic blood pressure values used for systolic-diastolic hypertension 1
• Treatment studies have demonstrated that reducing systolic blood pressure in isolated systolic hypertension reduces cardiovascular events 2, 3

Clinical Pitfalls to Avoid

• Focusing exclusively on diastolic blood pressure can be misleading, especially in older adults 6
• Overtreatment leading to excessive lowering of diastolic pressure (below 60 mmHg) may increase risk in patients with coronary artery disease 1, 5
• Pulse pressure should be considered as complementary to systolic and diastolic measurements, not as an alternative 7
• When treating hypertension, the goal should be to reduce cardiovascular risk while maintaining adequate coronary perfusion pressure 4, 5

In conclusion, while both components are important, systolic blood pressure has emerged as the more critical target for cardiovascular risk reduction, particularly in middle-aged and elderly patients 2, 6.