Hypertension Knowledge Centre
Understanding Hypertension
The importance of Systolic Hypertension
The term “isolated systolic hypertension” (ISH) describes raised systolic blood pressure with normal or low diastolic blood pressure. Some guidelines recognise two grades of isolated systolic hypertension: 2,15
- Grade 1 ISH = 140-159/<90mmHg
- Grade 2 ISH = ≥160/<90mmHg.
Increasingly, attention is becoming focused on systolic, rather than diastolic, blood pressure as the major factor to control in patients older than 50 years with essential hypertension.2,14 Elevated systolic blood pressure (SBP) is a powerful predictor of all-cause mortality, coronary artery disease, stroke and renal disease.16
Systolic blood pressure rises continuously with age, while diastolic blood pressure (DBP) increases until about age 55 years and then usually falls.17 The majority of older hypertensive patients have systolic predominant hypertension, and optimal therapy in these patients should be to reduce SBP while minimising the reduction of DBP.18
The MRFIT study showed a strong correlation between risk of stroke and increased blood pressure, especially systolic pressure (figure 2).4
Figure 2: MRFIT study. SBP and DBP at baseline and adjusted stroke mortality for men. Relative Risk was adjusted to take into account several factors including age, race, serum cholesterol, smoking and diabetic medication. Adapted from 4
The benefits of reducing raised SBP in elderly patients were shown in the SHEP and Syst-Eur studies.19,20 In the Syst-Eur study, which included 4,695 elderly patients with isolated systolic hypertension, treatment with the calcium channel blocker nitrendipine gave a 42% risk reduction of total stroke (figure 3). In the SHEP study, which included 4,736 elderly patients with isolated systolic hypertension, antihypertensive treatment produced a 36% reduction in the incidence of stroke, a 27% reduction in coronary artery disease, and a 49% reduction in congestive heart failure.
Figure 3: The Syst-Eur study in 4,695 elderly patients with isolated systolic hypertension showed a 42% reduction in stroke following antihypertensive treatment with the calcium channel blocker nitrendipine. Adapted from 20
