Unit 4: Cardiovascular System

The cardiovascular system 🫀

Anatomy of the Cardiovascular System

The cardiovascular system is sometimes called the circulatory system. It consists of the heart, which is a muscular pumping device, and a closed system of vessels called arteries, veins, and capillaries. 

As the name implies, blood contained in the circulatory system is pumped by the heart around a closed circle or circuit of vessels as it passes again and again through the various "circulations" of the body.

Human Heart with Blood Flow SimpleMed

Physiology

The purpose of the cardiovascular system is to provide adequate circulation of blood through the body.

Pulmonary circulation allows for the oxygenation of the blood, and systemic circulation provides for oxygenated blood and nutrients to reach the rest of the body.

Common Conditions and Disorders

  • Arrhythmias

  • Stroke

  • Congestive Heart Failure

  • Congenital Heart Disease

  • Coronary Heart Disease

  • Atherosclerosis

  • Angina Pectoris

Atherosclerosis

  • Thickening and hardening of the arteries

  • Deposits of fatty substances, cholesterol, waste products, calcium, and clotting materials form plaque on the artery walls

Coronary Heart Disease

  • Heart Attack 

    • A blockage of normal blood supply to an area of the heart that causes permanent damage

Angina Pectoris

  • Severe chest pain occurring as a result of reduced oxygen flow to the heart

Arrhythmias

  • An irregularity in the heartbeat

    • Tachycardia

      • Racing heart in the absence of exercise or anxiety

    • Bradycardia

      • Abnormally slow heartbeat

Congestive Heart Failure

  • When the heart muscle is damaged or overworked and lacks the strength to keep blood circulating normally through the body

    • Rheumatic fever, pneumonia, heart attack, radiation, chemotherapy and many other conditions can damage the heart muscle

Congenital and Rheumatic Heart Disease

  • Congenital Heart Disease is a defect that is present at birth

  • Rheumatic Heart Disease is caused by an untreated strep infection (rheumatic fever) of the throat

Stroke

  • When the brain is damaged because the blood supply
    to the brain is interrupted

    • Thrombus
      (blood clot)

    • Embolus
      (a wandering clot)

    • Aneurysm
      (a weakened blood vessel that bulges and may burst)

  • Minor strokes may cause temporary dizziness or slight weakness or numbness

  • More serious strokes may cause speech impairments, memory problems, and loss of motor control

  • Some strokes that affect parts of the brain that regulate heart and lung function can kill a person in minutes

Reducing Cardiovascular Disease Risks

  • Avoid tobacco

  • Cut back on fats and cholesterol

  • Monitor your cholesterol levels

  • Reduce your intake of saturated fats

  • Lose weight

  • Increase the amount of fiber you eat

  • Exercise

  • Control your blood pressure

  • Manage stress

What is Blood Pressure?

Blood pressure is the pressure exerted on vessel walls and is expressed as two numbers.

   -the higher number is the systolic BP, which is found when the heart is contracting.

   -the lower number is the diastolic BP, which is found when the heart relaxes.

Hypertension (HTN)

Hypertension is a risk factor for heart disease, stroke and kidney disease.

Antihypertensives work to lower BP (blood pressure) by dilating blood vessels, slowing heart rate, and increasing elimination of fluids from the body.  Often more than one drug will be needed

Beta Blockers

Beta blockers are medications that reduce blood pressure. 

Beta blockers work by blocking the effects of the neurotransmitter epinephrine, also known as adrenaline.

Therapeutic effects:  They cause the heart to beat more slowly and with less force, which lowers blood pressure. Beta blockers also help widen veins and arteries to improve blood flow.

Beta Blockers (Suffix: -olol)

BW:  abrupt discontinuation

SE: dizziness, fatigue

DI:  other drugs that lower BP, alcohol, nasal decongestants,   

       albuterol

  • If the drug is withdrawn for 48 to 72 hours BP can rebound to unsafe levels which can lead to chest pain or even heart attack.

  • Use with caution with diabetics who are prone to hypoglycemia (low blood sugar).  Beta blockers can mask symptoms of low blood sugar.

    Calcium Channel Blockers

    Calcium channel blockers are medications used to lower blood pressure. They work by preventing calcium from entering the cells of the heart and arteries. By blocking calcium, calcium channel blockers allow the blood vessel walls to widen and relax and blood pressure is lowered


    These medications may also be prescribed to relieve chest pain (angina) and control an irregular heartbeat.


    Therapeutic effect:  Stops calcium from entering cells of the heart and blood vessels which reduces resistance in peripheral blood vessels and relaxes vascular smooth muscle.  This decreases BP, regulates heart rate, and reduces chest pain.


    SE: headache (HA), edema, tiredness and

         dizziness

    DI: other drugs that lower BP

    Do NOT drink Grapefruit Juice if taking nifedipine. It increases the levels of nifedipine in the blood and can affect heart rate and BP

ACE Inhibitors

Angiotensin-converting enzyme inhibitors (ACE inhibitors) are a class of medications that help lower your blood pressure and can protect your kidneys from damage caused by diabetes and HTN. They’re used to treat cardiovascular conditions like high blood pressure and heart failure.

ACE Inhibitors (Suffix: -pril)

Therapeutic effect:  They decrease BP and prevent heart failure by blocking or reducing the enzyme that constricts blood vessels.  This keeps blood vessels open and causes better blood flow, therefore, decreasing  BP.

BW: fetal toxicity

SE: drug induced dry cough, angioedema,                     

       hypotension, dizziness, increased  potassium levels

DI:  other medications that lower BP; potassium

       sparing diuretics and  potassium supplements

  • If the cough is bad enough the patient will usually be switched to another medication, often an ARB (angiotensin receptor blocker)

  • Angioedema: swelling under the skin that can be life threatening allergic reaction, manifested by swelling of the tongue, lips or eyes.  Discontinue and immediately go to the ER

    Angiotensin II Receptor Blockers (A2RBS)

    Similar to the work that ACE inhibitors do, angiotensin II receptor blockers help relax your veins and arteries to lower your blood pressure and make it easier for your heart to pump blood.  They can also be used for heart failure and kidney disease.


    Unlike ACE inhibitors, A2RBS reduce the action of angiotensin II to prevent blood vessel constriction whereas ACE inhibitors lower blood pressure by preventing the production of angiotensin II.

    Therapeutic effect:  It decreases BP and prevents heart failure by blocking or reducing the enzyme that constricts blood vessels.  This keeps blood vessels open and causes better blood flow, therefore, decreasing  BP.


    BW: fetal toxicity

    SE: dizziness, HA, fatigue

    DI: other drugs that lower BP, potassium supplements


    ***Do NOT use with ACE inhibitors

    Alpha Adrenergic Blockers

    Alpha adrenergic blockers lower blood pressure by preventing a hormone called norepinephrine from tightening the muscles in the walls of smaller arteries and veins. As a result, the blood vessels remain open and relaxed. This improves blood flow and lowers blood pressure.


    Because alpha adrenergic blockers also relax other muscles throughout the body they are sometimes used to improve urine flow in older men with prostate difficulties (BPH)

Therapeutic effect:  They cause vasodilation, decreasing peripheral resistance which decreases BP.

SE: dizziness, orthostatic hypotension, HA, tiredness

DI: other drugs that lower BP and drugs to treat ED

Diuretics

Diuretics are used to treat edema (swelling due to fluid buildup). Most of these medicines help your kidneys remove salt and water through the urine. This lowers the amount of fluid flowing through your veins and arteries. As a result, blood pressure goes down.

There are three types of diuretics:

  • Thiazide

  • Loop

  • Potassium sparing


    Each type of diuretic affects a different part of your kidneys. Some pills combine more than one type of diuretic or combine a diuretic with another blood pressure medication.

Diuretics should always be taken in the morning; a patient should expect increase in urinary frequency and volume.

Therapeutic effect:  Used to treat edema (swelling due to fluid buildup) caused by heart, lung and kidney disease. 


Loop and Thiazide Diuretics (furosemide and HCTZ):

SE: hypokalemia, hypotension, weakness, dizziness, photosensitivity,

       GI upset

Hypokalemia could lead to arrhythmias, altered mental status, muscle cramps 

Potassium Sparing Diuretics (spironolactone and triamterene):

SE: hyperkalemia, nausea

Hyperkalemia could lead to heart damage, palpitations and possibly cause a heart attack

Miscellaneous Cardiovascular Drugs

An electrolyte replacement, potassium supplement, used to treat/prevent hypokalemia

SE: N/V, abdominal discomfort

**Give with or after meals and take with a full glass of water to decrease GI upset. If

   possible do not lie down immediately after taking.

Antihyperlipidemics (used to lower cholesterol)

  • Drugs that treat hyperlipidemia, a condition marked by elevated cholesterol, phospholipids, and/or triglycerides in the blood

Cholesterol :  the waxy substance  made in the body derived from lipids (molecules that make up the building blocks of the structure and function of living cells) present in the body and essential for healthy cell function.

  • Proteins and carbohydrates, as well as fat, are responsible for natural cholesterol production.

  • Excess cholesterol causes fatty deposits and plaque to develop in the blood vessels, which cause the artery to become narrowed and blocked. This impairs the flow of blood to the body and if plaque ruptures from the arterial wall it can form into a clot.

Lipo means fat 

Lipoproteins are groups of proteins carrying fats in the blood
Lipidemia is excess fat in the blood

Hyperlipidemic is too much fat in the blood system


Healthy total cholesterol levels are below 200mg/dL

Cholesterol levels are measured as total cholesterol, LDL  (low-density lipoprotein) and HDL (high-density lipoprotein).

LDL is considered the “bad cholesterol” and will build up on the arterial walls, causing them to harden and narrow therefore blocking the blood vessels and leads to other cardiovascular problems

HDL is considered the “good cholesterol” and its job is to pick up cholesterol in the body (break up blockages in the blood vessels) and deliver it to the liver; 

Hypercholesterolemia is high cholesterol and can cause the narrowing of the blood vessels due to plaque formation that may result in heart attacks and/or strokes

Antihyperlipidemics :
Statins (HMG-COA Reductase Inhibitors)

Prevent the production of LDL by blocking a key enzyme in the liver that makes it;  therefore, lowering the amount of cholesterol in the blood. 

Bronchodilators use different moa :b2 agonist, leukotriene receptor antagonist, anticholinergic

Used to treat high cholesterol by preventing the production of LDL by blocking a key enzyme in the liver that makes it, therefore, lowering the amount of cholesterol in the blood.  Statins can lower LDL cholesterol by up to 50% or more.

SE:  muscle/joint pain/aches/fatigue, HA, N/V, diarrhea, lower back pain, 

DI:  grapefruit/grapefruit juice( decreases the metabolism of drug and causes drug to accumulate in the body, increase in SE), some antibiotics (clarithromycin), some antifungals (itraconazole)  

     Pregnancy:  Category X (contraindicated)

Antihyperlipidemics :
Cholesterol Absorption Inhibitor

Used to prevent the small intestine from absorbing cholesterol, lowering LDL and triglycerides. 

SE:  abdominal cramps, diarrhea, HA, back pain, muscle/joint pain

DI: blood thinners (warfarin), fibrates

May use with statins

Antihyperlipidemics :Fibrates


They work by decreasing your triglycerides (a type of fat transported

in the blood, mostly after a meal and then stored in the fat cells) .  They can 

also increase HDL.

SE: abdominal pain, diarrhea, HA, leg cramps, nausea

DI: anticoagulants (warfarin), other drugs that lower cholesterol

Do NOT use in patients with liver, kidney or gallbladder disease.

Antihyperlipidemics: Omega 3

Helps to decrease the amount of triglycerides the body makes and increase HDL levels. 

Used to help lower levels of certain triglycerides.  Thought to decrease the amount of triglyceride the body makes and increase HDL levels.

It is a type of fat found in fish oil (salmon)

Take with food, swallow capsules whole. Do not crush, chew, or dissolve the 

capsules.  Do not take if allergic to  fish or shellfish

SE: upset stomach, burping, strange taste in mouth may occur

Antihyperlipidemics: Niacin (water-soluble B vitamin)
Helps to decrease the amount of triglycerides the body makes and increase HDL levels

Treats high cholesterol and triglyceride levels as well as niacin deficiency.  Not used as frequently now.

SE: flushing, stomach upset

Blood Clot Risk Factors ( Thrombus (pl. thrombi) )

  • Smoking

  • Overweight and obesity

  • Pregnancy

  • Prolonged bed rest due to surgery, hospitalization or illness.

  • Long periods of sitting such as car or plane trips

  • Use of birth control pills or hormone replacement therapy

  • Cancer

  2 Classes that Decrease Risk of Blood Clots

  1. Anticoagulant: prevents clot formation by inhibiting clotting factors; may prevent existing clots from expanding; often used to treat DVT, pulmonary embolism and acute cardioembolic stroke (stroke resulting from the heart circulating an emboli)

  2. Antiplatelet: reduce risk of clot formation by inhibiting platelet aggregation (sticking or clumping together of platelets); used to prevent recurrent thrombotic strokes and in high risk patients for stroke.

Anticoagulants and Anticoagulant Agents
Blood thinner

  • Treatment and prevention of blood clots

    • Deep vein thrombosis (DVT)

    • Stroke 

    • Pulmonary embolism (PE)


    Agents

  • Heparin 

  • Low-molecular weight heparin

  • Warfarin

  • Oral Active Direct Factor Xa inhibitor

  • Antiplatelets

Heparin

  • Inhibits clotting cascade which inactivates thrombin formation and factor Xa

  • Only given IV or SC to treat and prevent blood clots, usually in a hospital setting; requires frequent testing

  • NEVER give IM (will cause a hematoma)

  • Measured in units

  • Given post-operatively

  • Derived from porcine (pork) mucosal tissue

  • Do not confuse concentrations

  • ISMP High Alert Medication

  • Cannot dissolve a clot already formed


    Low Molecular Weight Heparins:

    enoxaparin (Lovenox) & dalteparin (Fragmin)

    Less risk of bleeding than heparin

  • Given sub-Q

  • Given less frequently than heparin

  • Expensive 

  • Prophylaxis for surgery (abdominal, knee replacement, hip replacement); drug of choice in pregnancy

  • "Bridge therapy" for warfarin (used to go from heparin to warfarin)

  • Also derived from porcine

Warfarin (Coumadin)

  • Prevents production of vitamin K-dependent clotting factors

  • Rapidly and completely absorbed

  • Takes 3-4 days to achieve therapeutic effect

  • Prevents future clot formation and extension of formed clots

  • NTI drug

  • Take same time everyday

  • No aspirin or NSAIDs

  • SE: skin necrosis, purple toe syndrome

  • Avoid or eat a consistent amount of foods high in vitamin K (green leafy veggies)

  • Mephyton (phytonadione) is the antidote

  • Must monitor international normalized ratio (INR): the time it takes for blood to clot

    *do NOT take if pregnant or planning to become pregnant.

Anticoagulants

SE: bleeding of the gums, unusual bleeding, red or brown urine or  

      stools, tarry stools, cuts that won’t stop bleeding, bruising, 

DI:  several, NSAIDS, aspirin

BW: Risk of major or fatal bleeding

Direct Oral Anticoagulant Agents: Xarelto, Eliquis, Pradaxa

  • Do not require INR monitoring

  • No dietary restrictions

  • Used to prevent MI and stroke

  • Bleeding risk

  • Pradaxa must be stored and dispensed in its original container and be used within 4 months of opening.

  • BW: premature discontinuation of increases the risk of thrombotic events; spinal/epidural hematoma

  • Xarelto 15 mg must be taken with food

  • Xarelto and Pradaxa can be crushed

Antiplatelet Drugs
Must be stopped 5-7 days prior to surgery because of bleeding risks

  • Clopidogrel (Plavix) - approved to prevent recurrence of MI and stroke often used in patients who have had recent clot related strokes, heart attack or angina

  •  Aspirin is an NSAID but slows platelet aggregation, which prevents clotting.  Often prescribed to prevent thrombus formation, but can also be taken for pain, fever, or inflammation.

  • DI for clopidogrel: omeprazole/esomeprazole

Vasodilators

These dilate the blood vessels, particularly those of the heart, increase oxygen and blood flow to relieve chest pain, and/or reduce the workload on the heart. 

Vasodilators: Nitrates

Nitroglycerin and isosorbide (dinitrate or mononitrate) are nitrates, they dilate the blood vessels, particularly those of the heart, increase oxygen and blood flow to relieve chest pain, and/or reduce the workload on the heart.  

Used to treat angina (chest pain due to inadequate blood supply to the heart) and heart failure

SE: HA, dizziness, flushing, tachycardia

DI: *erectile dysfunction drugs [sildenafil (Viagra), tadalafil (Cialis), and vardenafil (Levitra)] *severe drop in BP

Nitrostat (SL nitroglycerin)
Sublingual tablet taken at the first sign of chest pain.  

  • May repeat the dose every 5 minutes for a total of three doses.  If chest pain persists patient should get to the ER as quickly as possible.

  • Tablet is to be dissolved under the tongue, avoid swallowing.

  • Highly sensitive to air and light and should be replaced every 3 to 6 months.

  • Due to its emergency use, nitroglycerin should never be dispensed in a child resistant container. 

  • Always stored in its original container.