Antihypertensives Menu

Why Do I Have Hypertension?

AntihypertensivesBecause of the spectrum of cardiovascular disorders to which hypertension (high blood pressure) belongs and to which it contributes, treatment is indicated as soon as the diagnosis is made to prevent or keep at a minimum its risk of comorbidities:

  • Heart disease
  • Atherosclerosis
  • Stroke
  • Kidney failure
  • Thromboembolic disease
  • Circulatory problems
  • Myocardial ischemia and infarction
  • Stroke

Hypertension is treated via nonpharmacologic and pharmacologic protocols.

The nonpharmacologic protocols involve alterations in lifestyle:

  • Weight management
  • Smoking cessation
  • Exercise
  • Mitigation of a sedentary lifestyle or occupation by frequent ambulation
  • Diet alteration to include salt restriction and lipid considerations
  • If diabetic, strict glycemic control and maintenance of a target hemoglobin A1c of <7-8%

The pharmacologic approach to hypertension involves the following types of antihypertensive medications, initially only one, in what is called monotherapy.

  • Diuretics
  • Calcium channel blockers (dihydropyridines)
  • ACE (angiotensin-converting enzyme) inhibitors
  • ARBs (angiotensin II receptor blockers)

Diuretics diminish intravascular volume, which lowers the pressure head against the arterial walls. Calcium channel activity increases heart contractility and vascular smooth muscle contractility, so that blocking these will create vasodilation (again, lowering the pressure head against the arterial walls); this can be achieved without an increase in cardiac contractility if the dihydropyridine type is used.

Angiotensin converting enzyme is part of the renin-angiotensin system in the kidneys which impacts blood pressure by a conversion of angiotensin I to angiotensin II, a potent vasoconstrictor (increases the pressure head against the arterial walls). ACE inhibitors block this conversion and the ARBs block the receptors that turn on when filled with angiotensin II. Either way, the vasoconstrictive effects from the kidneys are aborted, lowering blood pressure.

Diagnosis of Antihypertensives

Those with hypertension should have investigations into their general cardiac and cardiovascular health, since hypertension is one aspect of a spectrum of disease that includes atherosclerosis, vascular disease, thromboembolic disease, coronary artery disease, and ischemia in the heart and other organs.

Diagnosis begins with an in-depth history and a thorough physical exam, including a blood pressure.

Blood Pressure

To make the diagnosis of hypertension, the blood pressure in the office setting must be abnormal on at least 2 readings on at least 2 occasions. If there is doubt to the accuracy due to patient nervousness or other reasons, home monitoring can be done or ambulatory monitoring using wireless technology for prolonged BP monitoring.

The diagnosis of hypertension follows this algorithm:

  • Normal blood pressure: Systolic <120 mmHg/ diastolic <80 mmHg.
  • Elevated blood pressure: Systolic 120-129 mmHg/diastolic <80 mmHg.
  • Hypertension stage 1: Systolic 130-139 mmHg OR diastolic 80-89 mmHg.
  • Hypertension stage 2: Systolic ≥ 140 mmHg OR diastolic ≥ 90 mmHg.

If there is a disparity in category between the systolic and diastolic pressures, the higher value determines the stage.

Blood Tests

  • CBC: To rule anemia and abnormalities of blood elements, including red blood cells (RBCs) and white blood cells (WBCs), as well as platelets.
  • Complete metabolic profile: To screen for liver and kidney disease and electrolyte imbalances, as well as a fasting glucose to identify those at risk for diabetes.
  • Clotting studies: To identify those with bleeding disorders.
  • Thyroid stimulating hormone (TSH): To rule out secondary hypertension due to a hyperactive thyroid gland.

Electrocardiogram

An ECG will identify comorbidities such as arrhythmias or ventricular enlargement. In combination with a stress test, it can assess exercise tolerance as well as identify angina with exertion.

Echocardiogram

If there is hypertension associated with structural abnormalities of the heart or with the heart valves, an ultrasound test is crucial to make the diagnosis.

Other Ultrasound

Ultrasound of arteries or veins can identify atherosclerotic plaques and thrombus formation that puts a hypertensive patient at risk for pulmonary embolism from the veins or organ ischemia/infarction from the arteries, including the heart from coronary artery disease or the brain from carotid artery disease.

Management of Hypertension

Whether or not antihypertensives are used, the best results come from alterations in lifestyle that favorably impact the blood pressure: weight loss, healthy diet, smoking cessation, nutritional counseling for glycemic control and management of lipids, and exercise.

Setting a Blood Pressure (BP) Goal

It is important that the patient and physician set a BP goal for therapy, based on the recommendations of the physician, and follow a timeline along which other therapeutic approaches are to be used if the goal is not met.

Monotherapy

When lifestyle alteration fails or when a patient is simply non-compliant in attempting it, a pharmacologic approach to hypertension is indicated. This involves the following types of medications, initially only one, in what is called monotherapy:

  • Diuretics
  • Calcium channel blockers (dihydropyridines)
  • ACE (angiotensin-converting enzyme inhibitors)
  • ARBs (angiotensin II receptor blockers)

Other Agents

  • Beta blockers: Beta blockers block the beta-sympathetic receptors which when filled cause vasoconstriction and increased cardiac contractility.
  • Alpha blockers: These block the alpha-sympathetic receptors but are not recommended.

The choice of which single agent to use can be influenced by a number of things, including race, diabetes, pregnancy, side effects, allergies, previous monotherapy failure with one of the others, and physician preference. For example, for African-Americans, a thiazide diuretic or long-acting calcium channel blocker should be used first. For those with renal disease, including diabetic kidney disease, an ACE inhibitor or ARB should be used. Younger patients do best with ACE inhibitors or ARBs and beta blockers.

When there is severe heart disease, myocardial infarction, or heart failure, a beta blocker can be added to the monotherapy to decrease the strain on the heart by blocking the adrenaline receptors that increase vasoconstriction and heart contractility.

Some diuretics can create a renal loss of potassium, so potassium levels can be monitored via blood tests (e.g., a complete metabolic profile–CMP). The CMP can also monitor sodium and calcium whose elevations are warning signals for kidney disease, a common comorbidity with hypertension.

Sequential monotherapy: when one agent fails, depending on the urgency of bringing the pressure down, another monotherapy choice can be tried.

Combination Therapy

When a BP goal is not met with monotherapy, meaning the systolic and the diastolic pressures remain more than 20 mmHg and 10 mmHg above the target goal, respectively, a combination therapy can be used, e.g., a long-acting dihydropyridine calcium channel blocker + a long-acting ACE inhibitor or ARB.

Treatment for Dyslipidemia

Those with abnormal cholesterol or triglyceride levels treated with antihypertensives may show improvement in their lipid profile; also, those treated with statins for dyslipidemia may show improvement in their blood pressures. Thus, when a patient has both hypertension and abnormal lipids, both should be treated, but this is true for each of the conditions, anyway, regardless of the presence of the other. This benefit falls away when thiazide diuretics are at higher doses than usual or with the addition of beta blockers.

Prevention of Hypertension

Prevention of hypertension, and by way of this, prevention of needing hypertensives to mitigate heart disease, depends on health living. Blood pressure increases with age or due to genetics, and although these cannot be prevented, they can be influenced by a heart-healthy lifestyle. Anyone with a family history of hypertension or cardiac disease should adopt these changes as soon as possible, even in their childhood or teens.

  • Weight management
  • Smoking cessation
  • Exercise
  • Avoidance of high risk behavior, such as illicit drug abuse
  • Alcohol moderation
  • Statin therapy for dyslipidemia

With an established diagnosis of hypertension requiring antihypertensives, prevention of worsening hypertension or the cardiovascular comorbidities associated with it is via the above recommendations, but also via compliance with the treatment plan designed to achieve one’s target BP goal.

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This information is provided by Vascular Health Clinics and is not intended to replace the medical advice of your doctor or healthcare provider. Please consult your healthcare provider for advice about a specific medical condition.

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