Isolated Systolic Hypertension – Causes, Symptoms, Treatment

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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.

Systolic hypertension is the predominant form of hypertension in the elderly population. Traditionally it has been defined as systolic blood pressure (SBP) above 140 mmHg with diastolic blood pressure (DBP) of less than 90 mmHg. It is estimated that 15 percent of people 60 years old 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

Types of Isolated Systolic Hypertension

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.

Whitecoat Hypertension

  • Consistently elevated office blood pressure but normal out-of-office blood pressure

Masked Hypertension

  • Consistently elevated out-of-office blood pressure but normal office blood pressure

Psuedo-hypertension

  • Result of calcified blood vessels that cause incompressible of the peripheral arteries
  • Blood pressure cuff unable to measure the intraluminal blood pressure accurately
  • This causes a false elevation of blood pressure reading
  • Use of standing blood pressure measurement can help to differentiate pseudo-hypertension from true hypertension
  • Patients with poorly controlled blood pressure should be evaluated for pseudo-hypertension prior to being labeled as resistant hypertension.

Understanding readings

Blood pressure is measured in millimeters of mercury (mm Hg).

There are several different blood pressure categories, which are currently defined as the following:

Normal Systolic less than 120 mm Hg AND diastolic less than 80 mm Hg
Elevated Systolic between 120–129 mm Hg AND diastolic less than 80 mm Hg
Hypertension Stage 1 Systolic between 130–139 mm Hg OR diastolic between 80–89 mm Hg
Hypertension Stage 2 Systolic of 140 mm Hg or higher OR diastolic of 90 mm Hg or higher
Hypertensive crisis (a medical emergency) Systolic of higher than 180 mm Hg AND/OR diastolic higher than 120 mm Hg

ISH is when you have a systolic blood pressure reading of 140 mm Hg or higher, and a diastolic blood pressure reading of less than 90 mm Hg.

Organ Systems Involved

An abrupt rise in blood pressure or a prolonged elevation of blood pressure may cause end-organ damage in the heart, kidneys, brain, vascular tree, and more.

  • Vascular System

    • Endothelial dysfunction/injury
    • Remodeling
    • Atherosclerosis
    • Aortic aneurysm
    • Aortic dissection
  • Kidney

    • Albuminuria
    • Proteinuria
    • Chronic renal insufficiency
    • Renal failure
  • Cerebrovascular System

    • Stroke
    • Hemorrhage
    • Lacunar infarcts
    • Vascular dementia
    • Retinopathy
  • Heart

    • Left ventricular hypertrophy
    • Myocardial infarction
    • Heart failure
    • Atrial fibrillation

Causes of Isolated Systolic Hypertension

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, 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 an 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.

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Systolic hypertension may be due to reduced compliance of the aorta with increasing age.[rx] This increases the load on the ventricle and compromises coronary blood flow, eventually resulting in left ventricular hypertrophy, coronary ischemia, and heart failure.[rx]

Contemporary science shows an immersed boundary method of computational illustration of a single heartbeat. Applied to physiologic models, immersed boundary theory sees the heart as a great folded semisolid sail fielding and retrieving a vicious blood mass. The sail likened to Windkessel affects physiology, gives and received.

Diagnosis of Isolated Systolic Hypertension

Isolated systolic hypertension, like any other hypertensive disorder, 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:

  • Intake of precipitating agents such as nonsteroidal anti-inflammatory drugs, steroids, sympathomimetics, cocaine, steroids, estrogen
  • Risk factors such as smoking, diabetes, dyslipidemia, obesity, sedentary lifestyle, unhealthy diet
  • Diet, including high salt, processed food, high fat, and alcohol intake
  • Family history of hypertension, renal disease, diabetes, or cardiovascular disease
  • Symptoms of secondary causes such as spells of tremor, sweating or tachycardia, muscle weakness, thinning of the skin, depression, hematuria, loud snoring, and daytime somnolence
  • Symptoms of end-organ damage such as headaches, loss of visual acuity, dyspnea, chest pain, and claudication

Physical Examination

Accurate Blood Pressure Measurement

  • Reassess normal blood pressure yearly.
  • Take blood pressure after the patient rests for 5 minutes.
  • The patient should sit in a chair with both feet flat on the ground and the back straight.
  • The patient’s arm should be placed on a flat surface at the level of the chest or heart.
  • Choosing the right cuff size is important.
  • SBP is the first Korotkoff sound.
  • DBP is the fifth Korotkoff sound.
  • Obtain an average of 2 to 3 blood pressure measurements on 2 or 3 separate occasions to confirm a hypertension diagnosis.

General Appearance

  • Body mass index calculation
  • Signs of Cushing syndrome such as buffalo hump, moon face, thinning of the skin, and red or purple striae.
  • Restlessness
  • Sweating
  • Flushing
  • Neurofibromatosis

Neck

  • Thyroid enlargement
  • Carotid bruits

Fundoscopy

  • Papilledema
  • Cotton wool spots
  • Arteriolar narrowing
  • Arteriovenous nicking
  • Hemorrhage

Heart

  • Gallop rhythm, S4
  • Heave
  • Jugular venous distension

Lungs

  • Rales
  • Rhonchi

Abdomen

  • Enlarged kidneys
  • Aorta or renal bruits

Neurologic

  • Visual changes
  • Confusion
  • focal weakness

Extremities

  • Peripheral pulses
  • Pedal edema
  • Cold peripheral limbs

Lab Test And Imaging

Further Evaluation 

When systolic hypertension is suspected based on the reliable measurements, perform a further evaluation to determine the following.

  • Presence or absence of cardiovascular risk factors
  • The extent of the end-organ damage
  • Identifiable causes of hypertension
  • Concomitant clinical conditions affecting prognosis and treatment

Routine Laboratory and Clinical Investigation

These tests should be performed to evaluate cardiovascular risk and concomitant diseases.

  • 12-lead electrocardiographic (left ventricular hypertrophy features, atrial dilation, and arrhythmias)
  • Lipid panels (calculate 10-year atherosclerotic cardiovascular disease (ASCVD) risk)
  • Serum creatinine (with an estimation of GFR)
  • Serum electrolytes (sodium and potassium)
  • Thyroid-stimulating hormone
  • Urine analysis (proteinuria)
  • Urine microalbuminuria

Additional Tests

Perform the following tests based on the relevant history, physical examination, and routine laboratory findings.

  • Hemoglobin A1c
  • Serum uric acid
  • Ankle-brachial index
  • Renal ultrasound and renal duplex Doppler ultrasonography
  • Quantitative proteinuria (urine protein to creatinine ratio, 24-hour urine protein)
  • Echocardiogram (patient with heart failure)
  • Specific tests to search for secondary causes of hypertension (plasma free metanephrines, 24-hour urinary cortisol, aldosterone-renin ratio)

Treatment of Isolated Systolic Hypertension

Goal

Based on these studies, treating to a systolic blood pressure of 140, as long as the diastolic blood pressure is 68 or more, seems safe. Corroborating this, a reanalysis of the SHEP data suggests allowing the diastolic to go below 70 may increase adverse effects.[rx]

A meta-analysis of individual patient data from randomized controlled trials found the lowest diastolic blood pressure for which cardiovascular outcomes improve is 85 mm Hg for untreated hypertensives and 80 mm Hg for treated hypertensives.[rx] The authors concluded “poor health conditions leading to low blood pressure and an increased risk for death probably explain the J-shaped curve”.[rx] Interpreting the meta-analysis is difficult, but avoiding a diastolic blood pressure below 68–70 mm Hg seems reasonable because:

  • The low value of 85 mm Hg for treated hypertensives in the meta-analysis is higher than the value of 68–70 mm Hg that is suggested by the two major randomized controlled trials of isolated systolic hypertension
  • The two largest trials in the meta-analysis, Hypertension Detection and Follow-up Program (HDFP)[rx] and Medical Research Council trial in mild hypertension (MRC1)[rx] were predominantly middle-aged subjects, all of whom had diastolic hypertension before treatment.
  • The independent contributions of diseases and factors other than hypertension versus effects of treatment are not clear in the meta-analysis.

A more contemporary meta-analysis by the Cochrane Hypertension group found no benefits in terms of reduced mortality or morbidity from treating patients to lower diastolic targets than 90–100 mmHg.[rx]

New classifications of blood pressure according to the 2017 ACC/AHA guidelines

Normal Blood Pressure 

  • SBP < 120 mmHg and DBP < 80 mmHg
  • Promote lifestyle modification.

Elevated Blood Pressure

  • SBP 120 to 129 mmHg and DBP < 80 mmHg
  • Initiate nonpharmacologic therapy and reassess in three to six months.

Hypertension Stage 1

  • SBP 130 to 139 mmHg or DBP 80 to 89 mmHg
  • Patient without ASCVD or 10-year ASCVD risk < 10%: initiate nonpharmacologic therapy for all patients and reassess in three to six months.
  • Patient with ASCVD or 10-year ASCVD risk >/= 10%: initiate nonpharmacologic therapy and single oral antihypertensive agent and reassess patient in one month.

Hypertension Stage 2

  • : SBP > 139 mmHg or DBP > 89 mmHg
  • Initiate nonpharmacologic therapy and single oral antihypertensive agent and reassess patient in one month.

*If the blood pressure goal is not met, assess and optimize adherence to therapy or consider intensification of therapy.

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*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.

Treatment of hypertension can be divided into nonpharmacologic and pharmacologic therapy.

Nonpharmacologic Therapy

  • Recommended for all patients, regardless of the reading of the blood pressure.
  • Restrict dietary salt (aim for 1.5 g or less per day). Randomized controlled trials have shown that moderate sodium reduction can result in an average blood pressure reduction of 4.8/2.5 mmHg).
  • Weight loss (every 1 pound of weight loss will result in a reduction of 1 mmHg blood pressure).
  • Start a Dietary Approaches to Stop Hypertension (DASH) diet (rich in fruits, vegetables, whole grains, fish, and low-fat dairy products). A clinical trial has shown that the DASH diet helps to reduce blood pressure by an average of 6/4 mmHg.
  • Increase physical activity. Aerobic and resistance training can reduce blood pressure by an average of 4/3 to 6/3 mmHg, irrespective of body weight.
  • Limit alcohol intake to no more than one alcoholic drink per day for women and two for men.
  • Take a potassium supplement (unless contraindicated in chronic kidney disease patients).
  • Quit smoking.
  • Use stress management.

Pharmacologic Therapy

  • In general, start off with a single-agent oral antihypertensive drug therapy, especially in the elderly because of the risk of orthostatic hypotension.
  • An exception to the above is when the initial SBP is above 160 or blood pressure is > 20/10 mmHg above the goal of blood pressure, which often needs the initiation of two oral antihypertensive agents.
  • The four major classes of oral antihypertensive agents include thiazide-like diuretics (chlorthalidone and indapamide), dihydropyridine calcium channel blockers (CCBs: amlodipine, nifedipine, nitrendipine), angiotensin-converting enzyme inhibitors (ACEi: lisinopril, ramipril), and angiotensin receptor blockers (ARBs: losartan, valsartan).
  • Randomized controlled trials have shown that thiazide-like diuretics and CCBs are the preferred first-line agents in reducing the risk of stroke and other morbidities in patients with isolated systolic hypertension.
  • The dose of the single oral antihypertensive agent should be titrated to the maximum before initiating a second oral antihypertensive agent.
  • In patients who require two oral antihypertensive agents, a combination of thiazide-like diuretic and CCB is the preferred strategy.
  • ACEi or ARB is often used in the patient with compelling indications such as heart failure reduced ejection, post-myocardial infarction, diabetes, or chronic kidney disease.
  • A combination of either ACEi or ARB with CCB or a thiazide-like diuretic can be considered.
  • It is important to note that ACEi should never be used concomitantly with ARB under any circumstances.
  • Patients with secondary causes of hypertension should have their respective diseases addressed concurrently.
  • Studies have shown that the use of beta-blockers in the management of hypertension is inferior compared with ARB, ACEi or CCB for cardiovascular and stroke risk reduction.

Blood Pressure Goals

  • SHEP and HYVET trials have shown significant benefits of antihypertensive treatment in patients with the goal of SBP <150 mmHg.
  • The VALsartan in Elderly Isolated Systolic Hypertension (VALISH) trial showed no significant difference in the primary outcome of sudden death, fatal or nonfatal myocardial infarction and stroke, heart failure death, or other cardiovascular death among patients with strict (< 140 mmHg) and moderate (140 to 150 mmHg) SBP control.
  • However, the VALISH trial was underpowered due to the low number of events.
  • Hence, the optimal SBP in patients with hypertensive disorder remained a controversial topic.
  • The most recent Systolic Blood Pressure Intervention Trial (SPRINT) has shown that intensive SBP target of < 120 mmHg improved the cardiovascular outcomes and the overall survival compared to the standard SBP target of 135 to 139 mmHg.
  • However, aggressive SBP lowering may be harmful in the elderly and incite more adverse effects such as hypotension, end-organ hypoperfusion (causing acute kidney injury, and intracranial hypoperfusion which may link to cognitive decline), and polypharmacy.
  • It is suggested that a goal blood pressure of < 130/80 mmHg is appropriate as long as the patient tolerates it.
  • Otherwise, < 140/90 mmHg is considered reasonable in patients who are in the elderly population and patients with labile blood pressure or polypharmacy.
  • Management strategies should always be patient-centered, with the aim of optimizing blood pressure control and avoiding polypharmacy, especially in the elderly.

J-curve Phenomenon

  • Various studies have shown a J-curve association between blood pressure with risk of myocardial infarction and death.
  • Patients with isolated systolic hypertension who receive antihypertensive treatment may precipitously drop their DBP as well.
  • As myocardial perfusion occurs mainly during diastole, an excessive drop in DBP may increase the risk of cardiovascular disease and death.

Lifestyle changes

You may also need to make some lifestyle changes as part of your ISH treatment plan. These can include:

  • Losing weight. This can help lower your blood pressure. In fact, for every two pounds you lose, you could lower your blood pressure by about 1 mm Hg.
  • Eating a heart-healthy diet. You should also aim to reduce the amount of sodium in your diet. Consider the DASH diet, which emphasizes eating:
    • vegetables
    •  whole grains
    •  low-fat dairy products
    •  fruits
  • Exercising. Not only can exercise help you lower your blood pressure, but it can help you control your weight and stress levels. Aim to perform some sort of aerobic exercise for at least 30 minutes most days of the week.
  • Decreasing alcohol consumption. Healthy alcohol intake is one drink per day for women and two per day for men.
  • Quitting smoking. Smoking can raise your blood pressure and also contribute to a variety of other health problems.
  • Managing stress. Stress can raise your blood pressure, so finding ways to relieve it are important. Examples of techniques to help lower stress are meditation and deep breathing exercises.
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References

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