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Diseases of the Peripheral Vasculature

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What are the important pathologies of the aorta (2)?
-Aneurysm
-Dissection
What are the important pathologies associated with occlusive arterial disease (3)?
-Peripheral arterial disease (PAD) due to atherosclerosis
-Acute arterial occlusion (thrombo- or atheroembolism)
-Vasculitic syndromes
What are the important pathologies associated with venous disease (2)?
-Varicose veins and sequelae
-Venous thrombosis is covered in Respiratory
What is the diameter of the normal aorta at its origin, in the ascending, descending and abdominal aortas?
-3cm
-3.8 to 4.5cm
-2 to 2.5cm
-About 2.5cm
What are the three layers of the arterial wall?
-Intima
-Media
-Adventitia
What are two common stressors on the normal aorta?
-Mechanical trauma induced by continuous high pulsatile pressure and shear stress
-With aging comes stiffening of the vasculature tissues and increased arterial pressure
What is an aneurysm?
It is a localized, blood-filled balloon-like bulge in the wall of a blood vessel.
What is a true aneurysm?
When the diameter of the localized area has increased by at least 50% and involves all three layers.
What are the two different kinds of true aneurysms?
-Fusiform
-Saccular
What is a fusiform aneurysm?
"Spindle-shaped" aneurysms are variable in both their diameter and length; their diameters can extend up to 20 cm (8 in). They often involve large portions of the ascending and transverse aortic arch, the abdominal aorta, or less frequently the iliac arteries.
What is a saccular aneurysm?
They are spherical in shape and involve only a portion of the vessel wall; they vary in size from 5 to 20 cm (8 in) in diameter, and are often filled, either partially or fully, by thrombus.
Which type of true aneurysm is most common?
A fusiform aneurysm, involving the entire circumference.
What is a false aneurysm?
Occurs when only the adventitia balloons out after an intimal rupture. Can occur at sites of infection or trauma.
Image of different types of aneurysms.
What is the most common location for aortic aneurysms?
The abdominal aorta followed by the thoracic aorta.
How is it decided whether there is a need for surgery when an aneurysm has occurred?
It is decided on a case by case basis. In the case of abdominal aortic aneurysms, when the aneurysm is greater than 4.5cm, surgery is considered.
What pathologies are associated causes of aneurysms (4)?
-Atherosclerosis
-Polygenetic potential
-Cystic medial necrosis
-Inflammation
What are the primary contributors to the development of a descending or thoracic aneurysm (5)?
-Atherosclerosis
-Smoking
-Dyslipidemia
-Male gender
-Advanced age
What is cystic medial necrosis?
The degeneration of the media of the vessel, it usually occurs in the ascending thoracic aorta and is associated with aging,W Marfan syndrome and Ehler-Danlos syndrome.
What role does inflammation play in the development of an aneurysm?
The size of an aneurysm is correlated with IL-6 and CRP levels.
What are the infrequent pathologies associated with the development of an aneurysm (3)?
-Infection
-Takayasu arteritis
-Giant cell arteritis
What is Marfan syndrome?
An inherited connective-tissue disorder transmitted as an autosomal dominant trait. Consists of mutations in the fibrillin-1 (FBN1) gene on chromosome 15, which encodes for the glycoprotein fibrillin. Fibrillin is a major building block of microfibrils, which constitute the structural components of the suspensory ligament of the lens and serve as substrates for elastin in the aorta and other connective tissues.
What is the major cause of mortality and morbidity in Marfan syndrome patients?
Aortic dilatation and dissection, with an average life expectancy of 40 to 40 years.
Describe the epidemiology of aortic dilatation in Marfan syndrome patients.
The prevalence of aortic dilatation in Marfan syndrome is 70-80%. It manifests at an early age and tends to be more common in men than women. A diastolic murmur over the aortic valve may be present.
What is Ehler-Danlos syndrome?
A heterogeneous group of inherited connective-tissue disorders characterized by joint hypermobility, cutaneous fragility, and hyperextensibility. Type IV is associated with arterial rupture and visceral perforation, with possible life-threatening consequences.
What is Takayasu arteritis?
It is an uncommon, chronic inflammatory disorder of unknown etiology affecting the aorta and its major branches. It predominantly affects women ages 15 to 25, with a female-to-male ratio of 9:1.
What is giant cell arteritis?
A vascular syndrome that affects predominantly cranial arteries.
Marfan syndrome can be difficult to diagnose, what is one significant sign of Marfan syndrome?
Arachnodactyly.
Does the absence of arachnodactyly rule out a diagnosis of Marfan syndrome?
No.
Give two tests for arachnodactyly.
-Wrist sign: positive if the distal phalanges of the first and fifth digits of one hand overlap when wrapped around the opposite wrist
-Thumb sign: positive if the thumb, when completely opposed within the clenched hand, projects beyond the ulnar border.
What is the typical clinical presentation of an aneurysm?
Most people are asymptomatic, but early signs can include noting a pulsatile mass (e.g. upper abdomen) or problems due to compression of adjacent structures (cough, hoarseness [recurrent laryngeal nerve], nonspecific GI symptoms).
An aneurysm should be included on your differential for what types of pain (7)?
-Chest
-Back
-Abdominal
-Buttock
-Groin
-Testicular
-Leg
Who should be screened for aneurysms (2)?
-Men ages 65 to 75 years old who have ever smoked
-Patients with a strong family history of abdominal aortic aneurysm.
What method is best used for screening for aneurysms?
Ultrasound.
What is the preferred method for assessing an aneurysm in an urgent situation, if the patient is clinically stable?
CT.
What is the interval for follow up if the abdominal aorta is less than 3cm?
No further testing needed.
What is the interval for follow up if the abdominal aorta is between 3cm and 4cm?
Every year.
What is the interval for follow up if the abdominal aorta is between 4cm and 4.5cm?
Every six months.
What is the interval for follow up if the abdominal aorta is greater than 4.5cm?
Immediately refer to a vascular surgeon.
When should surgery to repair an abdominal aortic aneurysm be considered in men?
When the diameter of the aneurysm reaches a maximal diameter of 5.5cm. Surgery also should be considered when the aneurysm expands by more than 0.6 to 0.8 cm per year.
What is the mortality associated with elective surgical repair of an aneurysm (3)?
-3-5% for thoracic aneurysms, depending on whether endovascular stent graft is possible or if cardiopulmonary bypass is needed
-1-2% for abdominal aortic aneurysms at high-volume institutions
-Long term outcomes are still being defined
What are the aortic aneurysm take home points?
-This chronic disease is often asymptomatic but must be considered in the pain differential
-The greater the diameter, the greater the risk of death from rupture or dissection
-Key management: beta-blockers and sometimes surgery
Give a chest pain differential diagnosis (12).
-Myocardial infarction
-Pericarditis
-Aortic dissection
-Pulmonary embolism
-Pneumonia
-Pneumothorax
-Esophageal spasm
-Acute cholecystitis
-Acute pancreatitis
-Exacerbation of COPD or asthma
-Costochondritis
-Panic attack
What are the signs and symptoms associated with pericaditis (2)?
-Pain changes with position
-Friction rub
What are the signs and symptoms associated with aortic dissection (4)?
-Tearing
-Ripping pain that migrates
-Asymmetry of arm blood pressures
-Widened mediastinum on chest x-ray
What are the signs and symptoms associated with pulmonary embolism (2)?
-Pronounced dyspnea
-Venous thrombosis risk factors
What are the signs and symptoms associated with pneumonia (2)?
-Cough, sputum, etc
-Abnormal chest x-ray
What are the signs and symptoms associated with pneumothorax (2)?
-Sharp, unilateral pleuritic pain
-Abnormal chest x-ray
What are the signs and symptoms associated with esophageal spasm (2)?
-Retrosternal pain that waxes and wanes
-Relieved by GI cocktail
What are the signs and symptoms associated with acute cholecystitis (2)?
-Gallbladder spasm affecting the right upper quadrant and may refer to right scapula
-Characteristic abdominal ultrasound
What are the signs and symptoms associated with acute pancreatitis (2)?
-Pancreatic enzymes may migrate to thorax
-A significant hemoperitoneum may put pressure on the diaphragm
What are the signs and symptoms associated with exacerbation of asthma or COPD (5)?
-History
-Dyspnea
-Wheezing
-Pulse oximetry
-Abnormal arterial blood gases
What are the signs and symptoms associated with costochondritis (1)?
Pain is reproduced by palpating the chest wall in a low risk patient.
When is chest pain used to diagnose panic attacks?
It is a diagnosis of last resort, you must rule out other diagnoses with testing.
Give the background of aortic dissection.
It is an acute, life threatening event which results from the unzipping of the intimal layer, causing bleeding into the lumen. It usually starts with a tear in the intimal layer, sometimes from a bleed within the medial layer.
What happens in an aortic dissection?
The intimal layer of the aortic wall tears, separating (dissecting) and causing a new, false channel to form within the artery wall. This can continue to expand, causing excruciating pain & pressure, and robs the distal arterial system of blood.
What pathology is aortic dissection related to?
The degeneration of arterial integrity secondary to aortic aneurysm expansion.
Which patients are most likely to experience an aortic dissection?
Men in their sixth or seventh decade. Two thirds of aortic dissection patients have hypertension.
What are the most common locations of aortic dissections (3)?
-65% ascending thoracic aorta
-20% descending thoracic aorta
-5% abdominal aorta
Where are aortic aneurysms most likely to occur?
In the abdominal aorta.
Where are aortic dissections most likely to occur?
In the thoracic aorta.
Aortic dissection image.
Image of the three types of aortic dissection.
Which type of aortic dissection is most common, least common?
-Two thirds are type A
-One third are type B
What is the difference between type A and type B aortic dissections?
Type A involves the ascending aorta, type B does not.
What is the number one symptom of aortic dissection?
Sudden, severe chest pain with a tearing or ripping quality. Located in the anterior chest with type A, between the scapulae with type B. The pain can radiate anywhere in the thorax or abdomen.
What are the signs of aortic dissection (5)?
-Elevated BP.
-Different systolic blood pressure in arms if a subclavian artery has occluded
-Neurologic deficits if dissection extends to carotids
-Early diastolic murmur if aortic regurgitation occurs
-Signs of cardiac tamponade if leakage into the pericardial sac
How helpful is a 12 lead ECG in diagnosing an aortic dissection?
Not very, it is usually within normal limits or has non-specific abnormalities.
Describe the process of diagnostic imaging for diagnosing an aortic dissection (3).
-The preliminary imaging choice is a chest x-ray
-If the patient is hemodynamically stable, CT angiography with 3D reconstruction is warranted
-If the patient is not hemodynamically stable, echocardiogram
CT image of an aortic dissection with 3D reconstruction.
What are the complications of aortic dissection (3)?
-Rupture (up to 90% mortality)
-Occlusion of the aortic branch vessels
-Distortion of aortic annulus
What are the consequences associated with a rupture due to an aortic dissection (3)?
-Pericardial tamponade
-Hemomediastinum
-Hemothorax (usually left-sided)
What is pericardial tamponade?
Sufficient blood in the space between the muscle and pericardium to compress the heart.
What is hemomediastinum?
An effusion of blood into the mediastinum.
What is a hemothorax?
An accumulation of blood in the pleural space.
What is the result of an occlusion of the carotid artery due to an aortic dissection?
Stroke.
What is the result of an occlusion of the coronary artery due to an aortic dissection?
Myocardial infarction.
What is the result of an occlusion of the splanchnic artery due to an aortic dissection?
Organ infarction.
What is the result of an occlusion of renal artery due to an aortic dissection?
Renal failure.
What is the result of an occlusion of the iliac, subclavian or brachiocephalic artery due to an aortic dissection?
Limb ischemia.
What is the aortic annulus?
The fibrous rings surrounding the arterial orifices that serve for the attachment of the great vessels and semilunar valves.
What is the consequence of the distortion of the aortic annulus due to an aortic dissection?
Aortic regurgitation.
Possible sequelae of dissection of the ascending thoracic aorta: Damage to the aortic valve image.
Possible sequelae of dissection of the ascending thoracic aorta: Tearing of a coronary artery image.
Possible sequelae of dissection of the ascending thoracic aorta: Cardiac tamponade image.
What is the best approach to have when treating an aortic dissection?
Conservative, unless the risks of the surgery are reasonable for a given patient.
What are the goals in the treatment of aortic dissection (3)?
-Arrest progression of the dissecting channel
-Reduction of systolic blood pressure to between 100 to 120 mmHg
-Decrease left ventricle contraction to shear wall stress
Which medications are indicated for aortic dissection (2)?
-Beta blockers
-Vasodilators (sodium nitroprusside)
What does the literature say about surgery for type A aortic dissections?
Surgical treatment of type A acute aortic dissection remains a challenge, especially in elderly patients or in patients with a critical preoperative status. Overall mortality rate was 19.8% with an exponential increase with age (50% over 80 years).
What does the literature say about surgery for type B aortic dissections?
Early surgery does not improve outcomes. Actuarial survival rate of medically managed patients was 98.4% at 1 month and 93.5% at 8 years. CONCLUSIONS: Medical treatment of type B acute aortic dissection produced good results. Surgical intervention for type B dissection should be done when the maximum aortic diameter exceeds 60 mm.
What are the take home points of aortic dissection (3)?
-Though aneurysms of the thoracic aorta are not as common as abdominal aortic aneurysms, they carry a higher risk of dissection and rupture
-Severe chest pain with dyspnea and other symptoms requires emergent assessment
-CT angiography is the preferred emergency imaging for diagnosis; however, if the patient is hemodynamically unstable, echocardiography is used
What is peripheral arterial disease?
It generally refers to atherosclerotic disease of pelvic and lower extremity arteries. The upper extremities can be affected, but it is not common.
Describe the pathology of peripheral artery disease.
It is identical to coronary artery disease. 50% of patients with peripheral artery disease also have clinically significant coronary artery disease.
The pathophysiology of peripheral artery disease is also similar to that of coronary artery disease. Explain how (4).
-In general, ischemia is induced by exercise and improved or relieved by rest
-Pain at rest signifies severe disease
-Over time, leg muscle fibers degenerate and atrophy
-As the disease progresses, blood flow is so impaired that even resting metabolic requirements are not met, so ischemia is prolonged, and tissue necrosis and gangrene may occur.
Describe the pathogenesis of peripheral artery disease.
It is related to the development of atherosclerotic plaques. They form preferentially at arterial branch points and sites of increased turbulence. There is an increased risk of peripheral artery disease with diabetes and age (most patients are over 70).
What are the most common arteries involved in the pathogenesis of peripheral artery disease and what is the pain associated with each artery (3)?
-Femoral and popliteal: 80-90% of patients, pain in the calf
-Tibial and popliteal: 40-50% of patients, pain in the calf
-Abdominal aorta and iliac: 30% of patients, pain in the buttock, hip, thigh or calf
What is the most common body part for patients to experience pain with peripheral artery disease?
Their calf.
What is claudication?
Impairment in walking.
How many patients with peripheral artery disease are actually symptomatic?
Less than 50%!
What are the claudication symptoms that can experienced with peripheral artery disease?
Depending on the artery affected, the patient will have buttock, thigh or calf discomfort precipitated by walking and relieved by rest.
What are common signs of peripheral artery disease (4)?
-Loss of pulses distal to the stenosis and slow capillary refill
-Increased turbulence at the stenosis causes bruits
-Distal limbs may have muscle atrophy, pallor, cynosis, alopecia, cool and shiny skin, ulcers, necrosis
-Positive Buerger's sign
What is a positive Buerger's sign?
Elevation of the extremity causes pallor or cyanosis, and restoring to dependent position results in color changing to red.
What is the best screening test for peripheral artery disease?
The ankle-brachial index, which compares the ratio of blood pressure in the ankles to the arms with manometry and doppler to detect blood flow. Normal is less than or equal to 1.
What is the ankle-brachial index which indicates a diagnosis of peripheral artery disease?
Less than 0.9.
Which ankle-brachial measurements are most useful?
Measurements done before and after exercise (5 minutes on a treadmill) are most useful. Even if the ABI is normal at rest, the value after exercise may drop, indicating PAD risk.
Which screening exam can provide additional information to the the results of the ankle-brachial reflex and has the possibility of localizing the lesion of peripheral artery disease?
Limb segmental systolic pressure measurements and pulse volume recordings.
What is the gold standard of diagnostic imaging for peripheral artery disease?
Contrast angiography.
When is diagnostic imaging indicated for peripheral artery disease?
Imaging is generally done by the vascular surgeon at the time that revascularization is being considered (in the event the patient fails medical therapy or has more profound ischemic changes).
Which environmental factor is most strongly related to peripheral artery disease?
Smoking, in contrast to coronary disease, prolonged smoking cessation did not appear to eliminate this risk completely.
What are the general treatment options for peripheral artery disease (2)?
-Risk reduction: smoking, blood pressure, lipids, diabetes
-Anti-platelet therapy
The National Cholesterol Education Program Adult Treatment Panel considers peripheral artery disease to be a coronary heart disease equivalent, what is their recommendation?
Reducing LDL cholesterol to < 100 mg/dL.
Why is anti-platelet therapy indicated for peripheral artery disease?
It reduces the risk of adverse coronary events in patients with peripheral atherosclerosis. Clopidogrel can be used as an alternative.
What is clopidogrel?
A thienopyridine class inhibitor of P2Y12 ADP platelet receptors.
What are the specific treatments indicated for peripheral artery disease (3)?
-Increase in exercise
-Cilostazol
-Pentoxifylline
What is the best approach to increasing exercise in a patient with peripheral artery disease?
A supervised walking program.
What is ciilstazol and what are the advantages of using it to treat peripheral artery disease?
-It is a selective phosphodiesterase inhibitor; it has vasodilator and platelet-inhibiting properties
-It has been shown to improve exercise capacity in patients with peripheral artery disease
What is pentoxifylline and what are the advantages of using it to treat peripheral artery disease?
-A substituted xanthine derivative, is thought to improve the deformability of red and white blood cells
-It may help prevent claudication in some
What are the blood pressure goals for patients with diabetes or renal disease that also have peripheral artery disease and what medications are indicated in these patients?
-< 140/90 or < 130/80
-Beta blockers and ACE inhibitors
When is surgery indicated for peripheral artery disease and what type of surgery is preferred?
-Surgery is indicated when medical therapy has failed or severe limb ischemia is present
-Percutaneous transluminal angioplasty is preferred over open surgery due to lower rates of short term mortality and complications
What is the prognosis for peripheral artery disease/coronary artery disease (3)?
-Approximately 30-50% of patients with symptomatic PAD have evidence of coronary artery disease based on clinical presentation and electrocardiogram
-Over 50% have significant coronary artery disease by coronary angiography
-Patients with PAD have a 15-30% 5-year mortality rate and a two- to sixfold increased risk of death from coronary heart disease
How does acute arterial occlusion present?
-Acute limb ischemia causing pain, paresthesias and motor weakness distal to the occlusion
-Loss of pulses, pallor, cool skin, cyanosis, positive Buerger's sign
What is the number one cause of acute arterial occlusion?
Thromboembolism, particularly emboli from the heart due to intracardiac stasis of blood flow.
What other pathologies are associated with a thromboembolism (5)?
-Atrial fibrillation
-Mitral stenosis
-Dilated cardiomyopathy
-MI
-Endocarditis
What is a rare cause of a thromboembolism?
A venous clot that has navigated through an atrial septal defect, also known as a paradoxical embolism.
Where do primary arterial thrombi develop?
At sites of endothelial damage or compromise.
Give an example of a clinical presentation of critical ischemia of the foot.
The patient had a sudden onset of foot discomfort, with coldness and loss of sensation in the toes and the dorsum of the foot. He had previously suffered from intermittent claudication and has evidence of chronic ischemia, including absence of hair and thinness of the skin. Arteriography is necessary to define the nature of the lesion.
What is an atheroembolism?
Bits of cholesterol, platelet clots and fibrin migrate distally and occlude small arteries in the muscle and skin.
What are the signs of an atheroembolism (5)?
-Localized cyanosis
-Necrosis
-Livedo reticularis
-Kidney failure
-Intestinal ischemia
What are the causes of atheroemboli (2)?
-50% of cases are spontaneous
-50% are caused by intra-arterial procedures, such as cardiac catheterization
What is livedo reticularis?
A common skin finding consisting of a mottled reticulated vascular pattern that appears like a lace-like purplish discoloration of the skin. The discoloration is caused by swelling of the venules owing to obstruction of capillaries by thrombi.
How is acute arterial occlusion diagnosed?
Mostly through clinical presentation and confirmed by angiography. Assessment is usually done by a vascular specialist.
What is the most important aspect of treatment of acute arterial occlusion?
Must be treated immediately, time is of the essence. Extensive, irreversible damage occurs within six hours.
Which drug is the first line of treatment for acute arterial occlusion?
Heparin is given IV to limit propagation of the clot.
What does definitive treatment of acute arterial occlusion involve?
Revascularization, either by surgical thromboembolectomy or chemical thrombolysis.
How is the procedure for a patient with acute arterial occlusion chosen (3)?
Depends on
-Severity of the ischemia
-Extent and location of the thrombus
-General medical condition of the patient
What is heparin?
An injectable anticoagulant (IV or SQ) with rapid action. It is used to prevent or stabilize clots but is not an effective thrombolytic.
What agent is used for chemical thrombolysis?
Tissue plasminogen activator.
Acute arterial occlusion can also be due to vasculitic syndromes, list them (4).
-Takasuya arteritis (rare)
-Giant cell arteritis
-Thromboangiitis obliterans (Beurger disease)
-Raynaud's Phenomenon (common)
List the high yield facts about Takasuya arteritis (3).
-Affects aorta and its branches
-Known as the "pulseless disease"
-Generally affects younger women
List the high yield facts about giant cell arteritis (2).
-Affects medium to large arteries, especially cranial vessels
-65% of patients are women over 50
List the high yield facts about thromboangiitis obliterans (4)
-Affects small arteries, especially distal arteries of the extremities
-Uncommon
-Affects younger men
-Strongly correlated with smoking
List the high yield facts about Raynaud's phenomenon (2).
-Vasoplastic disease
-Either rpimary or secondary form
How common are varicose veins?
They affect 10 to 20% of the population. They are more common in women than in men.
Do genes play a role in the development of varicose veins?
Yes, there is a genetic predisposition.
Describe the characteristics of primary varicose veins (2).
-Superficial veins are affected
-Caused by pregnancy, obesity and prolonged standing
Describe the characteristics of secondary varicose veins (2).
-Deep veins are affected
-Caused by abnormalities such as venous occlusion
What are the conservative treatments for varicose veins (3)?
-Elevation of the legs
-Avoiding prolonged standing
-Compression stockings
What are the cosmetic treatments for varicose veins (3)?
-Injecting sclerotic agents into small veins
-Laser therapy
-Larger veins can be treated with radiofrequency ablation and vein ligation or removal
Which maladies are considered to comprise venous disease (2)?
-Venous insufficiency
-Venous stasis dermatitis
What is venous insufficiency?
A chronic disorder, usually due to elevated leg vein pressure from varicose veins.
How does venous insufficiency lead to venous stasis dermatitis?
Over time, there is an increased venous hydrostatic pressure leading to an increase in the permeability of the dermal capillaries. This increased permeability enables macromolecules, such as fibrinogen, to leak out into the pericapillary tissue.
What are the consequences of developing venous stasis dermatitis (4)?
-Non-pitting (brawny) edema
-Long-term fibrotic changes
-Changes in the color and texture of the skin
-Red, pruritic patches of stasis dermatitis precede ulceration
How can venous stasis dermatitis be prevented (2)?
-Compression stockings
-Weight loss
What is superficial thrombophlebitis?
A benign disorder due to inflammation or thrombosis of a superficial vein.
What are the causes of superficial thrombophlebitis (2)?
-Spontaneous
-Iatrogenic
What are the clinical findings of superficial thrombophlebitis (3)?
-Erythema
-Tenderness
-Edema in skin overlying affected vein
What are the treatments available for superficial thrombophlebitis (4)?
-Local heat
-Continued ambulation
-Compression
-Acetasalicylic acid or NSAIDs
It is possible to have both DVT and superficial thrombophlebitis. If DVT is suspected, what further tests must be done?
-Appropriate labs
-Doppler ultrasound
Depiction of the difference between deep vein thrombosis and superficial thrombophlebitis.