Isolated systolic hypertension is the predominant form of hypertension in the elderly population. Traditionally defined as systolic blood pressure (SBP) above 140 mm Hg with diastolic blood pressure (DBP) of less than 90 mm Hg, it is estimated that 15% of people aged 60 years and above have isolated systolic hypertension. Per the 2017 American College of Cardiology/American Heart Association Blood Pressure Guideline, however, an SBP of 130 mm Hg is now considered hypertensive at all ages. The new definition of hypertension will lead to an increased number of elderly being diagnosed with high blood pressure. Isolated systolic hypertension remains an important public health concern as chronically untreated high SBP patients carry significant mortality and morbidity.
Most patients with hypertension have primary hypertension, which is also known as essential hypertension. Rarely, isolated systolic hypertension is attributed to other causes of secondary hypertension such as hypothyroidism/hyperthyroidism, chronic kidney disease, peripheral vascular disease, diabetes mellitus, aortic insufficiency, arteriovenous fistula, anemia, Paget disease, and atherosclerotic renal artery stenosis.
Isolated systolic hypertension is common in the elderly population. Based on data from the National Health and Nutrition Examination Survey 1999-2010, approximately 30% of persons aged 60 years and above have untreated isolated systolic hypertension, as compared with 6% in adults aged 40 to 50 years and 1.8% in young adults aged 18 to 39 years. As per the Framingham Heart Study, a person aged 65 years with normal blood pressure has a 90% lifetime risk of developing hypertension. Among the elderly group, women and non-Hispanic blacks have a higher prevalence of hypertensive disorders.
Isolated systolic hypertension, in most cases, develops as a result of the reduced elasticity of the arterial system. This is commonly seen among the elderly as there is increased deposition of calcium and collagen to the arterial wall. Hence, this may result in reduced compliance of the arterial vessels, decreased lumen-to-wall ratio, and increased thickening and fibrotic remodeling of the vascular intima and media. As a result, these stiffened conduit arteries lead to the increase in pulse pressure and pulse wave velocity, causing an elevation in SBP and a further decline in DBP. Similarly, chronic diseases such as the above causes of secondary hypertension may contribute to the same pathological process by accelerating the deposition of calcium and collagen to the arterial system and the fibrotic remodeling of the vascular walls.
Isolated systolic hypertension, like any other hypertensive disorders, often results in end-organ damage when untreated. Hence, early diagnosis, addressing modifiable risk factors, and initiating appropriate treatment are prudent to decrease morbidity and mortality. The important aspects of the history in the hypertensive patient include the following:
Accurate Blood Pressure Measurement
Routine laboratory and clinical investigation These tests should be performed to evaluate cardiovascular risk and concomitant diseases.
Additional testsPerform the following tests based on the relevant history, physical examination, and routine laboratory findings.
New classifications of blood pressure according to the 2017 ACC/AHA guidelines:
Normal Blood Pressure
Elevated Blood Pressure
Hypertension Stage 1
Hypertension Stage 2
*If the blood pressure goal is not met, assess and optimize adherence to therapy or consider intensification of therapy.
*If the blood pressure goal is met, reassess in three to six months.
Several clinical trials such as HYpertension in the Very Elderly (HYVET) and Systolic Hypertension in the Elderly Program (SHEP) have shown that active treatment of isolated systolic hypertension in older adults resulted in significant reductions in the all-cause mortality (13%), cardiovascular mortality (18%), and stroke (30%) and coronary (23%) events as compared with placebo.
Blood Pressure Goals
It is important to identify white coat hypertension and masked hypertension correctly as over- or under-treatment of hypertension can have significant morbidity and mortality.
White coat Hypertension
Isolated systolic hypertension is common in patients in the elderly population. SBP has a better prediction for risk of cardiovascular disease as compared to DBP. Hence, treatment of isolated systolic hypertension is beneficial to reduce all-cause mortality and cardiovascular risk and stroke. The optimal SBP remained unclear, but an SBP goal of < 140 mmHg and keeping DBP at 70 mmHg or higher are considered appropriate in most patient populations.