Isolated systolic hypertension — cut-off value, treatment and prognosis

Definition and cut-off. Isolated systolic hypertension (ISH) is defined as a systolic pressure of 140 mmHg or greater WITH a diastolic pressure of less than 90 mmHg. It is the commonest form of hypertension in older adults, accounting for the majority of hypertension after the age of 60, and its prevalence rises steadily with age. A wide pulse pressure (systolic minus diastolic, normally < 60 mmHg) is its defining haemodynamic feature and is itself a strong independent predictor of cardiovascular events.

Pathophysiology. ISH results from age-related stiffening of the large conduit arteries — degeneration and fragmentation of elastin with increased collagen deposition, calcification, endothelial dysfunction and reduced nitric oxide availability. Loss of the aortic "Windkessel" cushioning function means the stroke volume is ejected into a rigid tube, raising systolic pressure, while faster pulse-wave velocity causes the reflected wave to return during systole rather than diastole, further augmenting systolic pressure and lowering diastolic pressure. Contributory factors: high salt intake, obesity, diabetes, chronic kidney disease, and high-output states such as anaemia, thyrotoxicosis, aortic regurgitation, arteriovenous fistula and Paget's disease.

Clinical assessment and pitfalls. Most patients are asymptomatic. Confirm with repeated measurements and home or ambulatory monitoring. Three specific pitfalls in the old: (i) always measure standing blood pressure, since orthostatic hypotension coexists in up to a third and limits treatment; (ii) exclude pseudohypertension from rigid calcified arteries, suggested by a palpable radial artery despite cuff occlusion (Osler's sign) and by high readings without target-organ damage; (iii) look for white-coat and masked hypertension. Assess target-organ damage — ECG and echocardiography for left ventricular hypertrophy, eGFR and urine ACR, fundoscopy.

Treatment thresholds and targets. Treat when the systolic pressure is persistently ≥ 140 mmHg (or lower in high-risk patients), aiming for a systolic pressure below 130 mmHg where tolerated. The critical caution is that lowering systolic pressure inevitably lowers diastolic pressure further, and a diastolic pressure below about 60–65 mmHg may compromise coronary perfusion, which occurs in diastole — the "J-curve". Therefore titrate to symptoms and standing blood pressure, accept a higher systolic target in those with symptomatic postural hypotension, and relax targets in frailty, dementia, recurrent falls or limited life expectancy. Begin with lifestyle measures — salt restriction below 5 g daily, weight reduction, DASH-type diet, aerobic exercise, alcohol moderation and withdrawal of NSAIDs.

Drug treatment. Thiazide-like diuretics (indapamide, chlorthalidone) and dihydropyridine calcium channel blockers (amlodipine) are first-line, because they are the agents proven in the ISH trials and they specifically reduce arterial stiffness and central pressure. ACE inhibitors and ARBs are effective alternatives and are preferred with diabetes, chronic kidney disease, heart failure or previous myocardial infarction. Beta-blockers are less effective in ISH — by slowing the heart they increase stroke volume and, through wave reflection, may raise central aortic pressure — so they are used only for a compelling indication such as angina, prior MI or rate control. Start with one low-dose agent (or a low-dose single-pill combination), review 4-weekly, and add rather than maximise. Monitor electrolytes and renal function, and check for hyponatraemia, hypokalaemia, gout and postural dizziness.

Prognosis. ISH is not a benign consequence of ageing. Systolic pressure and pulse pressure are stronger predictors of cardiovascular events in older adults than diastolic pressure, and ISH carries an increased risk of stroke, heart failure, coronary events, atrial fibrillation, chronic kidney disease, cognitive decline and vascular dementia. The benefit of treatment is well established: SHEP reduced stroke by about 36%, Syst-Eur reduced stroke by about 42% and also reduced incident dementia, and HYVET, in patients aged 80 and over, showed reductions in stroke, heart failure and all-cause mortality — establishing that treating hypertension is worthwhile even in the very old. The counterweight is that over-treatment causes falls, syncope, fractures, acute kidney injury and electrolyte disturbance, so the outcome depends on careful individualised titration.

Intensive systolic lowering is now supported by trials conducted specifically in older adults. The STEP trial randomised Chinese patients aged 60–80 to a systolic target of 110–130 versus 130–150 mmHg and found a significant reduction in cardiovascular events in the intensive group, with no increase in falls, syncope or acute kidney injury; ESPRIT (2024) and BPROAD (2024, in diabetes) reached concordant conclusions. On this basis the 2025 AHA/ACC guideline sets a universal target of below 130/80 mmHg with encouragement toward below 120 mmHg systolic, and the 2024 ESC guideline targets 120–129 mmHg systolic where tolerated — both explicitly stating that chronological age alone should not raise the target, but frailty, symptomatic orthostatic hypotension and limited life expectancy should.