Chapter 20, part 2 Flashcards
Etiology of acute lower extremity ischemia
either embolism of a clot or plaque from a proximal source or local development of thrombus
What are the six Ps of acute lower extremity ischemia?
Pain Pallor Paresthesias Pulselessness Poikilothermia Paralysis
What is the most common presenting symptom of acute lower extremity ischemia?
Pain
Paralysis in acute LE ischemia?
A late finding and is indicative of advanced ischemia
Systemic effects of tissue necrosis
Acidosis Hyperkalemia Myoglobinuria Renal failure Sepsis Death
What should occur once the clinical dx has been made?
It is more advantageous to proceed directly to arteriography and definitive management to maximize the likelihood of limb salvage
Management of acute lower extremity ischemia
Systemic anticoagulation with heparin should be instituted immediately
First step in dx and intervention is arteriography
Complications of acute lower extremity ischemia
Compartment syndrome- 2%
Minor catheter-related bleeding
Bleeding requiring transfusion
Hemorrhagic stroke
Characteristics of compartment syndrome
Pain with passive stretch of the muscles and increased compartment pressures (>20 to 30 mm Hg)
Dx of compartment syndrome
Made by hx, PE, and a high index of suspicion
Tx of compartment syndrome
Four-compartment fasciotomy of the leg
Most common sx of chronic lower extremity ischemia
Intermittent claudication
Rest pain
Ischemic ulcers
Frank gangrene
What will most pts report in chronic lower extremity ischemia?
Heart dz
DM
Kidney dz
HTN
PE of chronic lower extremity ischemia
Diminished peripheral pulses Hair loss Skin atrophy Nail hypertrophy Elevation pallor Dependent rubor
What is typically the initial symptom of chronic lower extremity ischemia?
Intermittent claudication
Claudication
Extremity discomfort, pain or weakness consistently produced by exercise and promptly relieved by rest.
Sx generally occur one level below the area of disease
What are the most common conflicting diagnoses of claudication?
Neurogenic leg pain caused by spinal stenosis, nerve compression, and diabetic neuropathy.
Critical limb ischemia
The presence of ischemic rest pain, the presence of tissue loss, or gangrene secondary to arterial insufficiency
Ischemic ulcers
Usually result from minor traumatic injuries, which fail to heal because of lack of adequate blood supply
They are most common in areas of focal pressure on the foot are usually dry and punctate
Ulcers of venous insufficiency
Mostly located superior to the medial malleolus and are often moist, superficial, and diffuse
Also associated with hemosiderin skin pigmentation and venous varicosities
Gangrene
Characterized by cyanotic, anesthetic tissue associated with necrosis d/t inability of the arterial blood supply to meet minimal metabolic requirements
Classification of gangrene
Can be classified as dry or wet
Dry is more common in pts with atherosclerotic dz and frequently results from embolization to the toes or forefoot
Elective amputation is required
Wet gangrene is more common in diabetic pts who sustain unrecognized trauma to the foot
Mandates either complete debridement of infected, nonviable tissue or guillotine amputation
Diagnostic tests for chronic lower extremity ischemia
Measurement of segmental systolic blood pressures
ABI
Pulse volume recordings (PVRs)
What ABI is considered nl?
> 1.0
Difference in management between PAD and chronic limb ischemia
PAD warrant medical therapy
-Initial management is antiplatelet therapy and risk factor modification
-Exercise therapy
Revascularization is indicated for all functional pts
Tx of aortoiliac occlusive dz
Endovascular therapy for single stenoses of the common iliac artery or external iliac artery shorter than 3 cm
Surgical revascularization for more complex lesions
In pts with hostile abdomen or high surgical risk who cannot be revascularized with an endovascular approach for aortoiliac occlusive dz, what is the tx?
Axillobifemoral bypass grafting
For pts with unilateral iliac dz not amenable to endovascular therapy, what is the tx?
Unilateral aortofemoral grafting
How is endovascular therapy for infrainguinal dz different from aortoiliac dz?
The patency rates are lower
No more than two focal stenoses less than 3 cm in length should be treated
The role of primary stenting is unclear
Bypass grafting is indicated when endovascular therapy is inappropriate or inadequate
What is the option of choice for tibial-peroneal dz?
Femoral-distal bypass
What are the three common time points that bypass grafts fail?
Early: <30 days
Intermediate (30 days to 2 yrs)
Late (>2 yrs)
Causes of early bypass graft failure
Assumed to be related to a technical or judgement error, though infection and hypercoagulability are also possible
Causes of intermediate bypass graft failure
Most often caused by neointimal hyperplasia within a vein graft or at anastomotic sites
Causes of late bypass graft failure
Natural progression of atherosclerotic dz
Exam of bypass graft
Perioperatively
6 wks
3-mo intervals
for 2 yrs and every 6 mos after
Complications of interventions for chronic lower extremity ischemia
Two categories: those related to concomitant systemic illnesses and those related to surgery
First category examples: MI and renal failure
Surgical complications: pseudoaneurysm resulting from arterial puncture, compartment syndrome, and graft infection
RFs for AAA
Advanced age Atherosclerosis HTN Smoking hx Men First-degree FHx
Sx of AAA
Usually asymptomatic
Presence of sx such as abdominal or back pain signifies impending or active rupture
Presentation of rupture of AAA
Severe abdominal or back pain with associated hypotension, tachycardia, and shock
PE of AAA
May reveal a pulsatile abdominal mass, but only 30-40% of aneurysms are noted on PE
Dx of AAA
Often dxed accidentally by u/s or abd CT
CT is preferred
How to decide whether to operate in pts with asymptomatic AAA
Decision is largely driven by diameter criterion
Aneurysms greater than or equal to 5.5 cm should be electively repaired
What are the most common early complications of open AAA repair?
Paralytic ileus Coronary ischemia Cardiac arrhythmias Renal dysfunction PNA
What are the less common early complications of open AAA repair?
Ischemic colitis Impotence Paralysis Graft infection Pseudoaneurysm
Late complications of AAA open repair
Incisional hernia Pseudoaneurysm development Atherosclerotic graft occlusion Graft thrombosis Aortoenteric fistula
Device-related complications of endovascular aneurysm repair
Kinking
Occlusion
Thrombosis
Endoleak
Non-device related complications of endovascular aneurysm repair
Dissection or thrombosis of the access vessels
Contrast-induced nephropathy
Wound complications
Origin of aneurysmal disease that occurs in the renal, hepatic, and splenic arteries
Usually not of atherosclerotic etiology and tend to occur in younger pts
Tx of visceral aneurysms
Renal and hepatic aneurysms should be repaired when discovered
Closely monitor splenic aneurysms
-Those in pregnant women or women who may become pregnant and those larger than 2 cm in diameter should be repaired
Renal, hepatic and splenic aneurysms are treated with exclusion and bypass grafting
Tx of iliac artery aneurysms
Should be repaired if they are symptomatic, larger than 3 cm, or mycotic either endovascularly with a covered stenth or through open surgical bypass graft with exclusion of the aneurysm
Tx of femoral artery aneurysms
Should be repaired if they are symptomatic, larger than 2.5 cm, or mycotic
Exclusion of the aneurysm and bypass graft
Tx of popliteal artery aneurysms
Repaired if they are symptomatic, larger than 2 cm, or mycotic
Exclusion and bypass with saphenous vein graft, although recently stent grafting has gained support, especially in high-risk pts
Where are most upper extremity vascular dz lesions?
Proximal
What is the most commonly affected vessel of upper extremity vascular dz?
The subclavian artery
Subclavian steal syndrome
Occurs in the presence of a proximal stenosis or occlusion of the subclavian artery
The delivery of arterial blood to the ipsilateral extremity thus depends on reversed flow through the ipsilateral vertebral artery via the circle of Willis
Thoracic outlet syndrome
A constellation of vascular and/or neurologic sx, often without any physical findings and most commonly without an anatomic correlate
Caused by compression of the subclavian artery, vein, or branches of the brachial plexus
Pt complaints in thoracic outlet syndrome
Weakness Numbness Paresthesias Pain Swelling of the extremity
Where do the brachial plexus and subclavian artery pass through?
Through the narrow triangle formed by the anterior scalene muscle, the middle scalene muscle and the first rib (the scalene triangle)
What can cause compression of the brachial plexus, subclavian artery, and/or subclavian vein?
Presence of an anomalous cervical rib or hypertrophy of the anterior scalene muscle
Complaints of neurologic thoracic outlet syndrome
Weakness
Paresthesias and numbness typically occur in the hand and medial forearm
Pain in the subscapular, scapular and cervical regions
Physical findings of neurologic thoracic outlet syndrome
Weakness and atrophy of the triceps muscle, the intrinsic muscles of the hand, and the wrist flexors
Dx of neurologic thoracic outlet syndrome
Often based on hx, PE, and exclusion of other conditions
What is the mainstay of tx of neurologic thoracic outlet syndrome?
Conservative, with exercise and physical therapy providing symptomatic relief
Surgical tx of neurologic TOS should be reserved for refractory cases because major neurovascular complications are not uncommon
What does subclavian artery compression usually result from?
Hypertrophy of the anterior scalene muscle in athletes but may also be caused by the presence of a cervical rib.
Surgery for subclavian artery compression
Involves release of the scalene muscles and resection of bony abnormalities
Presentation of compression of subclavian vein in TOS
Presents as effort-induced thrombosis (Paget-von Schrotter disease)
Common in young men with a hx of strenuous upper extremity activity, with painful swelling of the affected arm
Dx of compression of subclavian vein
Venous duplex studies and venography
Tx of compression of subclavian vein
Recanalizing the subclavian vein with thombolytics and anticoagulation
What does acute embolic occlusion usually affect
The SMA and the embolus is typically from a cardiac source
What is the most common site for an embolus to lodge
At the origin of the middle colic artery, distal to the first jejunal branches
Classic finding of mesenteric ischemia
Pain out of proportion to physical examination
Common sx of mesenteric ischemia
Sudden onset of periumbilical pain
Diarrhea
vomiting
GI bleeding
Diagnostic test for mesenteric ischemia
If dx suspected before onset of peritoneal signs, mesenteric angiography is the procedure of choice
If embolism present, laparotomy should be performed immediately, with embolectomy of the SMA and resection of nonviable bowel
