Vascular Surgery - NMS Casebook

Question 1

How would you evaluate a patient suspected of having a transient ischaemic attack?

Answer 1

1. An examination for carotid bruits, residual neurologic deficit and evidence of cardiac disease - especially murmurs that might indicate an embolic source is necessary.
2. If murmur is present then an echocardiogram would be appropriate
3. In addition a duplex ultrasound study of the carotid vessels to check for stenosis or irregular plaque morphology is essential in all patients

Question 2

A patient has a diagnosis of a TIA. The necessary work-up is performed and duplex ultrasound studies of the carotid vessels reveals an 80% stenosis of the left internal carotid artery. What are your treatment options?

Answer 2

• Two therapeutic choices are available
  
  1. Medical treatment with aspirin
  2. Surgical therapy involving carotid endarterectomy
• It is demonstrated that for a stenosis of 70% or more in the internal carotid artery with ipsilateral symptoms, surgical treatment results in significant advantage in stroke prevention.

Question 3

What are the other indications for carotid endarterectomy?

Answer 3

1. Ipsilateral hemispheric neurological symptoms (amaurosis fugax, transient ischemic attack, completed stroke with major neurological recovery with greater than 70% internal carotid stenosis
2. Asymptomatic carotid bruit and greater 70% internal carotid stenosis

Question 4

What are some of the complications related to a carotid endarterectomy?

Answer 4

1. Injury to the hypoglossal nerve
2. Injury to the vagus nerve
3. Injury to marginal branch of the facial nerve

Question 5

What preoperative evaluation would you undertake for a carotid endarterectomy?

Answer 5

1. General medical condition of the patient should be satisfactory
2. Blood pressure should be well controlled - to avoid wide intraoperative BP swings
3. An appropriate cardiac evaluation is necessary before surgery
4. A carotid artery arteriogram is obtained to describe the anatomy of the lesion in more detail

Question 6

What are the basic steps for a carotid endarterectomy?

Answer 6

1. Incision is made along the sternocleidomastoid muscle - dissection performed down to carotid sheath
2. Sheath is opened - vagus nerve is protected, carotid artery is isolated - avoiding denervation of the carotid body
3. Internal carotid artery is exposed to level of the hypoglossal nerve - must not be injured
4. Patient is heparinized - vessels are clamped
5. Vessels are opened and plaque is dissected from underyling vessel media and adventitia
6. Vessel is then closed with or without a patch - neck is closed

Question 7

A 65 year old man comes to A&E with a history of sudden onset of pain in his right leg - and difficulty in moving the leg. He says the leg has been normal up until now. There is an absence of pulses in his lower extremities - including the femoral pulse in the right leg. Pulses are normal in the left leg. The right leg appears cool and cyanotic - decreased sensation throughout. All muscle groups are weak. What is your diagnosis?

Answer 7

• The patient probably has an acute arterial embolus in his right leg
• Absence of a right femoral pulse and presence of a left femoral pulse indicate that the embolus is most liekly at the right iliofemoral level

Question 8

What is most important in terms of immediate management of an acute vascular event in the leg?

Answer 8

1. Time
   
   • With an acute arterial embolus - the time interval between the ischemic event and clinical presentation are critical to successful limb salvage.
   • Revascularization more than 6 hours after ischemia may result in a severely impaired limb or even require amputation.

Question 9

For an acute arterial embolus in the leg what is appropriate treatment?

Answer 9

1. Administer heparin immediately
2. Proceed to operating room to allow the earliest revascularization

Question 10

For an acute arterial embolus what surgical procedure is necessary?

Answer 10

• A balloon catheter embolectomy is the procedure of choice
• It involves the following steps
  
  1. Femoral artery is exposed and opened under local anesthesia and proximal embolus is extracted using a balloon catheter
  2. Typically, thrombus is also removed from the distal vessels. An intraoperative arteriogram can then be performed to assess the adequacy of thrombus removal. If necessary it is possible to lyse the thrombus further with intra-arterial thrombolytic therapy if there is residual distal, small arterial thrombus
  3. Arteriotomy is closed - limb is then revascularized.

Question 11

Following an embolectomy your patient has good perfusion to the foot and toes - but now has developed an inability to dorsiflex the foot and tenderness in the calf. Explain.

Answer 11

• This is compartment syndrome.
• This condition is most common after revascularization of an acutely ischemic limb.
  
  • It should be suspected in any patient who has an ischemic or traumatic injury to a muscle group that causes acute muscular edema
• Compartment syndrome is also termed as ‘‘ischemia-reperfusion injury’’.
  
  • Because many muscles are encased in an inelastic, fascial compartment, edema increases the volume - ultimately the pressure within the compartment.
  • As pressure increases, muscle perfusion decreases - resulting in further ischemic injury
    
    • Worsens edema
  • As compartment pressure approaches 20-40 mmHg, irreversible ischemic injury of the muscles and nerves may occur.

Question 12

How would you manage compartment syndrome?

Answer 12

1. If you suspect compartment syndrome - do not wait for advanced symptoms such as motor or sensory loss, or loss of the distal arterial pulses
2. In this case a fasciotomy should open all four compartments in the calf
   
   1. muscles bulges out at excision, relieving the pressure and improving perfusion
   2. once the acute episode is resolved, a fasciotomy is typically closed with a split thickness graft
   3. during recovery, performance of physical therapy is important for maintenance of a full range of leg motion.

Question 13

Outline your long term management for compartment syndrome following a fasciotomy

Answer 13

• Most surgeons would place the patient on chronic anticoaguation therapy with warfarin
• Once the patient recovers - echocardiography and other diagnostic techniques such as aortography or CT of throacic and abdominal aorta should be used in search for an embolic source

Question 14

What arteries in the legs are typically involved in atherosclerotic occlusions?

Answer 14

1. With intermittent claudication, popliteal and pedal pulses are often absent, indicating at least an occlusion of the superficial artery - typically at the adductor hiatus.
2. Most common location for occlusive disease of the lower extremity - if the femoral pulse is absent - significant aortoiliac disease may be present.

Question 15

What are the signs of peripheral vascular insufficiency?

Answer 15

1. Claudication - reproducible muscle pain cramping or weakness typically of the calf muscles. It occurs during exercise and is relieved by rest
2. Rest pain - constant, severe, burning, forefoot pain
3. Ischemic ulceration - painful, non-healing ulceration - typically on the malleoni and toes
4. Gangrene - cyantoic, insensate tissue progressing to black tissue or wet gangrene if infection is present.

Question 16

A patient has symptoms of claudication but she has an absent femoral pulse on the left side. How would this affect your management?

Answer 16

1. A weak or absent femoral pulse suggests poor blood flow into the leg, which is strong evidence for aortoiliac occlusive disease. This occlusion could be the single cause of the patient’s symptoms or one of the several occlusions contributing to the symptoms
2. Aortoiliac occlusive disease is generally more progressive than more peripheral occlusive disease
3. Surgery is considered and treatment is more aggressive
4. Important issues are the status of the femoral pulse on the opposite side, evidence of small distal emboli and impotence in males and claudication in other locations such as thigh or buttock
5. If symptoms progress, aortoiliac reconstruction either with balloon dilatation and/or stent placement or surgical vascularization will be necessary

Question 17

If an arteriogram shows occlusion of the superficial femoral artery with distal reconstitution what is your management plan?

Answer 17

A reversed or in situ saphenous vein graft from the common femoral artery to the popliteal artery is typically used to bypass the obstructions.

Question 18

If an arteriogram shows high grade stenosis of the iliac artery but patency of the lower extremity vessels what is your management plan?

Answer 18

A surgical revascularization using a large diameter graft from the aorta to the femoral artery or by balloon dilatation and/or arterial stent placement is appropriate.

Question 19

If the arteriogram shows high grade stenosis of the iliac artery and occlusion of the superficial femoral artery, what is your manaement plan?

Answer 19

A lower extremity revascularization in addition to the aortoiliac reconstruction may be necessary. The patient has multi-level disease - the two procedures may be performed at the same time or sequentially - the inflow (aortoiliac occlusions) can be treated first - revascularization may be sufficient to relieve the symptoms.

Question 20

If an arteriogram shows occlusion of the superficial femoral and popliteal arteries with distal reconstitution what is your management plan?

Answer 20

Femoropopliteal bypass is indicated for such a case

Question 21

What type of vessel disease to diabetics have?

Answer 21

Typically, diabetics predominantly have tibial disease

Question 22

After vascular bypass surgery what follow-up would you recommend?

Answer 22

1. Frequent duplex examinations of the graft to allow early detection of graft stenoses
2. Start aspirin
3. Advise control of serum lipids
4. Provide education about foot care

Question 23

A 61 year old man reports calf and thigh pain on exertion - which is relieved slowly by rest. He also complains of impotence, and he has smoked 1.5 packs per day for 30 years. Physical examination reveals absent femoral and lower extremity pulses bilaterally and stigmata of chronic vascular insufficiency in the lower legs. What is your diagnosis?

Answer 23

Aortoiliac occlusive disease secondary to atherosclerosis (Leriche syndrome)

Question 24

How would you manage a patient with Leriche syndrome?

Answer 24

1. Lifestyle modification is appropriate if the operative risk for any procedure is prohibitive. However, without surgery, the patient will almost likely progress to amputation or death
2. Percutaneous transluminal angioplasty (PTA) often performed at the time of angiography is ideal if the patient has a single short-segment iliac stenosis
3. Aortobifemoral bypass - indicated in bilateral loss of femoral pulses

Question 25

Under what circumstances would you choose to do an axillofemoral bypass graft in a patient with aortoiliac occlusive disease?

Answer 25

In a patient who is at poor risk, this alternate procedure avoids a large transabdominal maneuver.

Question 26

What part of an aortobifemoral bypass graft operation has the greatest cardiovascular risk?

Answer 26

1. During induction of anesthesia 2. Times of hemorrhage or other stress 3. In this procedure the the heart is also at increased risk due to: 1. Aortic clamping and unclaming

Question 27

After the aortobifemoral bypass graft operation to faciliate revascularization - you examine the patient's peripheral circulation - you notice a painful, cyanotic big toe that was not present preoperatively. What is it?

Answer 27

* ''Trash-foot'' * The atheroembolization of fibrin, platelets or dislodged atherosclerotic debris - blocking small pedal or digital arteries and microvessels during unclamping.

Question 28

How would you manage ''trash-foot''?

Answer 28

* Heparinization followed by long-term antiplatelet therapy. * Site-directed thrombolytic therapy may decrease the area of injury but is usaully contraindicated because of recent surgry (thrombolysis can result in massive bleeding at the operative site even weeks after surgery) * The toe should be protected from injury and assessed for necrosis

Question 29

What are the steps in the repair of an abdominal aortic aneurysm?

Answer 29

1. Exploration of abdomen with the retroperitoneum on the left side of the abdomen overlying the aorta revealed by reflecting the duodenum medially and exposing the aorta from the left renal vein to bifrucation 2. Inferior mesenteric artery is controlled - IV heparin given - aorta and distal vessels are clamped - aorta is opened 3. Thrombus is removed - prosthetic graft of Dacron is sewn to proximal and distal vessels to reestablish continuity

Question 30

What are the post-operative problems that are common following AAA repair?

Answer 30

1. Initial 1-2 days - patients will have large third space losses and extra fluid requirements 2. By the third day - patients will mobilise this fluid - require diuresis and restriction of IV fluids * If not done then may develop respiratory difficulties from pulmonary edema - resulting in unplanned reintubation. 3. Monitored cardiologically - arrythmias from fluid and electrolyte shifts 4. MI from both the stress of the procedure and effects of aortic clamping and unclamping

Question 31

Following surgery for AAA - the patient returns to you complaining of impotence. What is your recommendation?

Answer 31

1. Erectile dysfunction should be assessed preoperatively 2. Iatrogenic causes during aortic dissection are due to interruption of the hypogastric circulation or autonomic nerves on the anterior surface of the aorta near the inferior mesenteric artery which course over the aortic bifurcation.

Question 32

A patient undergoes repair for a ruptured AAA. The patient develops fever and a small amount of bloody diarrhea on the third postoperative day. What is the diagnosis?

Answer 32

* This is ischemic injury to the colon * Ischemic colitis usually involves the rectosigmoid segment and is due to interruption of a patent inferior mesenteric artery in the setting of compromised blood flow from the superior mesenteric and hypogastric arteries.

Question 33

What are the clinical signs and symptoms if ischemic colitis?

Answer 33

* Postoperative symptoms include: * liquid brown or bloody diarrhea * abdominal pain * tenderness * prolonged ileus * increased abdominal distention * signs of sepsis or peritonitis

Question 34

What investigations would you choose to confirm ischemic colitis?

Answer 34

* Immediate sigmoidoscopy is necessary to establish a diagnosis. * The mucosa could appear edematous, hemorrhagic or necrotic

Question 35

What is your treatment plan for ischemic colitis?

Answer 35

* Bowel rest * Maintenance of adequate hydration and hematocrit * GI tract decompression * Antibiotics * Frequent reexamination - repeat endoscopy * Full thickness involvement requires resection of nonviable bowel and end colostomy

Question 36

A patient undergoes repair for a ruptured abdominal aortic aneurysm. Two months later, returns with fever and an inflammed femoral incision. What has happened?

Answer 36

* Vascular graft infection - one of the most serious complications of aortic surgery * graft infection most commonly results from contamination by skin flora - most often Staph.epidermidis or S.aureus

Question 37

What are some of the presenting signs of a vascular graft infection?

Answer 37

* Systemic sepsis * Wound abscess * Pseudoaneurysm * Sinus tract * GI hemorrhage * Abdominal or back pain * CT confirms diagnosis

Question 38

A patient undergoes repair for a ruptured AAA. One year later, the patient returns with an upper GI bleed. What is the likely diagnosis?

Answer 38

* Aortoenteric fistula * This lesion develops as a result of erosion of the graft into the third or fourth part of the duodenum

Question 39

How do you confirm a diagnosis of an aortoenteric fistula?

Answer 39

* Diagnosis is confirmed by endoscopy, CT of the abdomen or angiography * Treatment requires removal of the graft and repair of GI tract and extra-anatomic bypass.

Question 40

A 49 year old woman presents with a 6 month history of postprandial abdominal pain, 20 lb weight loss and intermittent diarrhea. On physical examination, multiple abdominal bruits are evident. What is your diagnosis?

Answer 40

Chronic mesenteric ischemia which is usually secondary to atherosclerotic occlusion of the celia and superior mesenteric arteries. Postprandial pain due to ischemia of the intestines causes fear of food, leading to weight loss.

Question 41

How would you evaluate a patient with a suspected case of mesenteric ischemia?

Answer 41

1. Mesenteric arteriogram to establish diagnosis * Then plan revascularization if appropriate