Blocked Artery Signs, Symptoms and Effects

Blockage within an artery (occlusion) may arise for a number of reasons that are outlined in narrowing artery. The most common causes are atherosclerosis and a thrombus or embolus. Often the formation of atheromatous plaque causes a partial blockage and is then followed by the formation of a thrombus (blood clot) at the site which leads to total occlusion of the artery.

While the focus is often on a blockage within an artery, any occlusion within a vein can impair venous drainage thereby causing a backflow and preventing oxygenated blood from reaching the target area.

Effects of a Blocked Artery

When there is a partial blockage within an artery, the flow of oxygenated blood to the target tissue or organ is reduced. Depending on the extent of the partial blockage and availability of collateral blood supplies, or lack thereof, the oxygen supply to the target area is reduced. Hypoxia (low oxygen state) has many effects on the target area :

  1. The target organ may shrink (atrophy)
  2. Ischemia, which is a form of tissue injury, may ensue.
  3. Cell death may occur (necrosis).

Atrophy and ischemia may be reversible. Cell death (necrosis) cannot be reversed.

Ischemia may be reversible to a certain point and eventually reaches a stage where it is irreversible. There is no set time period as to when ischemia may become irreversible. Depending on the site and extent of hypoxia, ischemia can become irreversible in less than an hour or longer.

Within the reversible stage, suitable therapeutic measures to restore blood flow and oxygen supply (reperfusion) may be adequate to prevent any further injury and avoid cell death. However, once the irreversible stage of ischemia is reached, cell death will undoubtedly follow. Under certain conditions, reperfusion may actually cause cell death and this is known as ischemic-reperfusion injury.

A complete blockage may not always result in a total lack of oxygen (anoxia). Since many tissues have collateral blood supplies, the blockage of a single artery may mean that oxygen can still reach the target area through alternative routes. This, however, may not be sufficient to sustain the target site and atrophy and ischemia will most likely occur due to a state of hypoxia.

If there is insufficient collateral blood supply and the occlusion is sudden, as with an embolus, ischemia and cell death will definitely occur. The size of the infarct may vary depending on the closest alternative blood supply. In some organs, like the heart (muscle), ischemia or an infarct may only occur when there is an increase in oxygen demand like during strenuous activity.

Signs and Symptoms of a Blocked Artery

  • Pain, numbness or tingling may be the first symptom of a significant narrowing. With brain tissue, which is impervious to pain, the symptoms of pain, numbness or tingling may be evident along the course of the nerve originating from the affected area.
  • Diminished function due to the reduced oxygen supply and the signs and symptoms varies on the site that is affected.
  • Heart (coronary artery)
  • Blockage may result in angina or a heart attack (myocardial infarction)
    • Chest pain with pain radiating down the arm (especially left arm), to the jaw, neck and/or back.
    • Shortness of breath (dyspnea)
    • Sweating
    • Rapid heart beat
    • Palpitations
    • Dizziness or fainting
    • Nausea
  • Brain (internal carotid, cerebral arteries)
  • Blockage may result in a transient ischemic attack (TIA) or a stroke (cerebrovascular accident / CVA)
    • Dizziness and/or fainting
    • One-sided weakness or numbness, often of the face and/or limbs
    • Difficulty moving or paralysis of the limbs
    • Impaired balance
    • Changes in vision – blurred, difficulty seeing
    • Difficulty speaking
    • Confusion and trouble comprehending speech of others
    • Headache
  • Kidney (renal artery)
  • Renal artery stenosis (narrowing) may remain silent (asymptomatic) for long periods of time especially if the blockage is only affecting one side and is partial. The overall function of the urinary system is not severely impaired if the unaffected kidney is healthy.
    • Severe hypertension that responds poorly to treatment
    • Changes in size and shape of the affected kidney (ultrasound)
    • Murmurs may be heard in the abdomen, neck or other areas (auscultation)
  • A complete blockage, especially if sudden (acute), may result in :
  • Lung (pulmonary artery)
  • Pulmonary embolism is the most common type of pulmonary artery blockage. Depending on the size of the embolus, age and underlying conditions, like the presence of chronic obstructive pulmonary disease (COPD), the signs and symptoms may vary.
    • Shortness of breath (dyspnea)
    • Chest pain
    • Rapid breathing
    • Dizziness and/or fainting
    • Cough
    • Abnormal breathing sounds
    • Clammy skin, cyanosis (blue tinge of the skin)
    • Excessive sweating
    • Rapid heartbeat
  • Legs (common iliac, femoral, popliteal, tibial, peroneal arteries)
  • Acute limb ischemia is discussed further under blood clot in the leg.
    • Pain
    • Paresthesia
    • Paleness (pallor)
    • Pulse is weak or absent on the affected leg
    • Paralysis
  • A blocked artery may affect any organ apart from those mentioned above.
    • Intestines (superior mesenteric artery) – ischemic bowel disease
    • Liver (hepatic artery) – ischemic hepatitis
    • Spleen (splenic artery) – splenic infarct

Related Articles

  1. Narrowing Artery – Causes of Arterial Stenosis
  2. What is Atherosclerosis? Narrow Artery, Hard Arteries Disease
  3. Thick Blood Vessel Wall – Causes of Thickened Artery, Vein