Disorders of the Aorta

Importance of the Aorta

• The aorta is the largest artery in the body.

• It is responsible for supplying oxygenated blood to vital organs and tissues.

Common Disorders of the Aorta

• Aneurysms

• Aortoiliac Occlusive Disease

• Aortic Dissection

• Focus will be primarily on aneurysms versus aortic dissection due to their common clinical presentation and potential for confusion, despite being very different conditions.

• These conditions differ in underlying cause, pathology, clinical presentation, and nursing interventions.

Aortic Aneurysm

• Definition: A bulge or widening of the aorta, caused by a weakening of the aortic wall.

• The weakened aortic wall stretches and forms a balloon-like structure.

• Symptoms: Can be asymptomatic, or cause a throbbing or pulsating sensation over the chest, back, or abdomen.

• Risk Factors:

  • High blood pressure

  • High cholesterol

  • Smoking

  • Family history

  • Increased incidence with age.

  • Can occur anywhere along the abdominal aorta.

Aortic Dissection

• Definition: A tear in the inner layer of the aorta that allows blood to flow between the layers of the aortic wall.

• Physiological Impact: When blood enters the aortic wall via a tear, the normal perfusion of oxygenated blood through the aorta is impaired or halts entirely.

• Symptoms:

  • Sudden, severe pain in the chest, back, and abdomen.

  • Pain radiates to the arms, legs, or neck.

  • Other symptoms include shortness of breath, nausea, and vomiting.

• Risk Factors:

  • High blood pressure

  • Connective tissue disorders

  • Aortic valve disease

Abdominal Aortic Aneurysm (AAA) - "Triple A"

• Visual Representation: Demonstrated as a clear outpouching of the aorta, typically pointed out by red arrows in diagrams.

• The aorta extends down the abdomen and bifurcates, feeding vital organs and tissues in the lower bilateral quadrants, particularly the kidneys.

• Impact on Perfusion: An outpouching (aneurysm) in this area can significantly impair perfusion to the bilateral kidneys.

• Risk Factors (Expanded):

  • Age

  • Male gender

  • High blood pressure

  • Coronary artery disease (CAD)

  • Family history

  • High cholesterol

  • Previous stroke

  • Smoking

  • Overweight or obesity

  • Genetic disorders (e.g., Marfan's disease, which affects the elasticity of vasculature).

  • Racial predisposition: White and Native Americans have a higher risk than African Americans, Hispanics, and American Asians.

Aortic Aneurysm Types

• Healthy Vessel: Intact inner wall, no bulging, unimpaired perfusion and forward blood flow.

• Saccular Aneurysm: Bulges or balloons out only on one side of the blood vessel.

• Fusiform Aneurysm: Bulges or balloons out on all sides of the blood vessel.

• Dissecting Aneurysm:

  • Most commonly seen in the thoracic aorta.

  • Part of the aortic wall, primarily the tunica media, splits into two layers.

  • This creates a false lumen (channel) within the aortic wall.

  • The initial aneurysm leads to decreased integrity of the inner wall, facilitating the formation of this false lumen.

  • Pooling of blood in the false lumen leads to impaired perfusion.

• False Aneurysm (Pseudoaneurysm):

  • Formation: Occurs when a tear or injury in the blood vessel wall allows blood to accumulate into the surrounding tissue, forming a sac-like structure.

  • Causes: Usually caused by trauma, surgery, or infection.

  • Key Differentiation from Classic Aneurysm:

    • Classic Aneurysm: The wall of the aneurysm is composed of the original layers of the blood vessel.

    • Pseudoaneurysm: The wall is formed by surrounding tissues (e.g., scar tissue, clotted blood) and does not contain the original layers of the blood vessel.

Assessment of Abdominal Aortic Aneurysm (Unruptured)

• Focused Assessment Areas: Thorax, upper legs, abdomen, back, and any pain radiating down the arms or legs.

• General Signs/Symptoms:

  • Pain

  • Syncope (due to decreased preload and secondary decreased cardiac output, resulting in low blood pressure).

  • Dyspnea (reduced oxygenated blood to the heart).

  • Increased pulse (compensatory mechanism for decreased blood flow).

  • Cyanosis (lack of oxygenated blood).

  • Weakness.

  • Hoarseness (compression of laryngeal nerves by the aneurysm).

• Abdominal Findings:

  • Prominent pulsation or pulsating mass (usually slightly left or right of the umbilicus).

  • Systolic bruit.

  • Abdominal tenderness.

  • Abdominal or lower back pain (flank pain).

Assessment Findings for Worsening or Ruptured AAA

• These findings are almost identical to signs and symptoms of hypovolemic shock.

• Symptoms:

  • Anxiety and agitation.

  • Cool, clammy skin.

  • Diaphoresis.

  • Confusion or loss of consciousness.

  • Decreased or abrupt halt in urine output.

  • Generalized weakness or lethargy.

  • Pale skin.

  • Rapid breathing.

• This is a medical emergency; nurses must differentiate between a worsening patient and a ruptured aneurysm.

• Important Note: Most aneurysms are asymptomatic until they become large enough to cause a problem or dissect.

Nursing Goals and Management (AAA)

• Primary Goal: Prevent a known aneurysm from rupturing.

• Patient Education: Teach patients in high-risk categories about risk factors and lifestyle modifications.

• Early Detection: Conduct proper assessments to recognize early clinical findings and initiate early treatment.

• Incidental Findings: Aneurysms are sometimes discovered incidentally during ultrasounds, CTs, or angiograms for unrelated issues. Education on risk factors is then crucial.

Postoperative Care for Aortic Aneurysm Repair

• Management depends on the patient's preoperative condition (aneurysm size, type, rupture status).

• ICU Monitoring: Requires very close monitoring in the ICU for approximately 24 to 72 hours.

• Priorities:

  • Graft patency.

  • Renal perfusion.

  • Blood pressure management.

• Key Assessments:

  • Hourly urine outputs for at least the first 12 to 24 hours postoperatively.

  • Hourly vascular checks, including frequent peripheral pulse assessments, skin temperature and color, capillary refill, sensation, and movement of extremities.

• Blood Pressure Management: Maintain adequate blood pressure to facilitate perfusion but not compromise graft integrity. Systolic blood pressure should remain under 140 mmHg postoperatively.

• Incision Site Care: Monitor for drainage and infection; administer antibiotics as prescribed.

• Activity Restrictions:

  • Limit elevation of the head of the bed to 45^ heta degrees.

  • No heavy lifting for 6 to 12 weeks to prevent stress or strain on the abdomen or graft site.

Ambulatory and Home Care for Aortic Aneurysm Patients

• Psychological Support: Encourage expression of concerns about the experience and recovery, as patients often feel they've had a "brush with death."

• Activity: Instruct the patient to gradually increase activities.

  • Carefully balance facilitating perfusion with avoiding strain on the graft.

  • No heavy lifting.

• Patient Education: Ensure the patient understands signs and symptoms of potential complications to recognize at home:

  • Infection

  • Bleeding

  • Renal impairment

  • Neurovascular changes (e.g., stroke)

Aortic Dissection (Detailed)

• Clarity: Aneurysms can occur in any vessel (e.g., brain, thoracic/abdominal aorta, heart). Aortic dissection specifically occurs in the aorta.

• Difference with Dissecting Aneurysm: A dissecting aneurysm implies an aneurysm was present first, leading to dissection. An aortic dissection is simply a tear in the inner wall allowing blood pooling between layers without a pre-existing aneurysm.

• Definition: A tear of the inside layer of the blood vessel wall that allows blood to flow between, and separate, the layers that make up the vessel wall.

• Impact: Blood pooling within the layers impairs forward perfusion of oxygen-rich blood.

• Clinical Manifestations:

  • Characterized by sudden, very severe, often inconsolable pain.

  • Patients report pain in the anterior chest or intrascapular areas.

  • As it progresses, pain radiates down the spine, to the abdomen, and to the legs.

  • Pain is described as sharp and "the worst pain ever."

• Mimicry of Other Medical Emergencies: High mortality is partly due to aortic dissection mimicking other common emergencies like myocardial infarction (MI), kidney stones, and strokes, leading to diagnostic delays.

• Stroke Mimic Explained:

  • If the aortic arch is involved in the dissection, it impairs perfusion to the right and left carotid and subclavian arteries, which feed the brain.

  • This abrupt and severe lack of cerebral perfusion can cause symptoms that mimic a stroke.

Rupture and Surgical Therapy

• Risk: Aortic dissection can lead to a complete rupture of the aorta.

• Surgical Indication: Surgical therapy is always indicated for a dissecting aorta or a dissecting aneurysm.

• Emergent Intervention: If ruptured, emergent surgical interventions are required.

• Mortality Rate: Despite all efforts, the mortality rate is 90 heta for any ruptured aneurysm or dissecting aorta.

  • This is due to exsanguination (internal hemorrhage) into the mediastinal, pleural, or abdominal cavities.

  • Exsanguination causes an abrupt stop in perfusion to all vital organs and tissues, including the brain and heart.

• Surgical Procedure: Involves resection of the dissected aortic segment or the aneurysm location, followed by replacement with a synthetic graft to restore aortic integrity.

• Outcomes: Women tend to experience poorer surgical outcomes and higher mortality rates than men.

• Postoperative Management: Nursing management is similar to that for an aortic aneurysm repair.