This document discusses vascular surgery, specifically acute arterial ischemia and chronic limb ischemia/peripheral artery disease (PAD). For acute arterial ischemia, urgent management is needed within 6 hours to prevent irreversible muscle damage. Etiologies include embolism and thrombosis. Clinical features include the 6 Ps. Investigations and treatment involve angiography, embolectomy, thrombectomy or bypass grafting. Chronic limb ischemia/PAD is usually due to atherosclerosis and presents with claudication or critical limb ischemia. Treatment involves risk factor modification, exercise, pharmacotherapy such as statins, and surgical revascularization if conservative measures fail.

1. Vascular Surgery
Dr. Okon, MD, MRCS

2. Acute Arterial Ischemia
● Acute occlusion of a peripheral artery that often threatens
limb viability.
● Urgent management required as skeletal muscle can
tolerate 6h of total ischemia before irreversible damage;
exception is acute-on-chronic occlusion, where previously
developed collaterals provide minimal perfusion.
● Tends to be lower extremity > upper extremity;
femoropopliteal > aortoiliac
● Paralysis with complete loss of sensation is sign of late
ischemia

3. ● Etiology and Risk Factors
● Embolism
● Cardiac: arrhythmias, endocarditis, MI, LV aneurysm, myxoma/cardiac
tumour, paradoxical embolism, valvular heart disease
– non-cardiac: mural thrombus within arterial aneurysms, atheroembolism
● Thrombosis
● ■ atherosclerotic obstruction
● ■ vasospasm
● ■ aortic or arterial dissection
● ■ arterial transection
●

4. ● Embolism vs. thrombosis
● ■ thrombosis is more common than embolism; usually in
superficial femoral artery
● ■ existing atherosclerotic plaques can rupture causing
thrombosis
● ■ previous vascular gras/reconstructions can fail and
thrombose leading to acute presentation
● ■ hypercoagulable states can contribute to thrombosis
● ■ embolism generally results in greater degree of ischemia
due to lack of collaterals

5. ● Suspect embolism in patients with the following features:
● ◆ acute onset (patient able to accurately recall the moment of
the event)
● ◆ history of embolism
● ◆ known embolic source (e.g. cardiac arrhythmias)
● ◆ no prior history of intermittent claudication
● ◆ normal pulse and Doppler in unaected limb
● Dx: Iatrogenic (e.g. occlusion at arterial access site),
compressive, traumatic (blunt or penetrating injuries) causes
of acute limb ischemia

6. Clinical Features
● • 6 Ps – all may not be present
● ■ Pain
– may be constant or elicited by passive movement;
absent in 20% of cases
● ■ Pallor: pale
– within a few hours becomes mottled cyanosis
● ■ Paresthesia
– light touch lost rst then other sensory modalities
●

7. ● ■ Paralysis/Power loss:
– most important, heralds impending non-salvageable
limb
● ■ Polar/Poikilothermia: cold
– leg becomes cold
● ■ Pulselessness
– helpful to determine site of occlusion; not always
reliable

8. Investigations
● History and physical exam are essential: depending on degree of
ischemia one may have to forego investigations and go straight to the
operating room
● Determine Rutherford classication based on physical findings and
Doppler signals
● Ankle Brachial Index (ABI): extension of physical exam, easily performed
at bedside
● ECG, troponin: rule out recent MI or arrhythmia
● CBC: rule out leukocytosis, thrombocytosis or thrombocytopenia in
patients receiving heparin (may suggest HITS)
● • PT/INR, PTT: patient anticoagulated/sub-therapeutic INR

9. ● Echo: identify wall motion abnormalities, intracardiac
thrombus, valvular disease, aortic dissection (Type A)
● • CT angiogram: identify underlying atherosclerosis,
aneurysm, aortic dissection, identify embolic source,
identify other end organs with emboli (e.g.
splenic/renal infarcts), identify level of the occlusion
and extent
● • Angiography: can be obtained in OR as part of
intervention or for treatment planning

10. Treatment
● Immediate heparinization with weight-based bolus (80 Units/kg) and continuous
infusion to titrate PTT to 70-90s
● If impaired neurovascular status: emergent revascularization (Rutherford category
IIb)
● If intact neurovascular status: may have time for workup (including CT angiogram)
● Identify and treat underlying cause
● ■ embolus: embolectomy
● ■ thrombus: thrombectomy ± bypass gra ± endovascular therapy
● ■ irreversible ischemia (i.e. Rutherford category III): primary amputation or
palliation/comfort measures
● • continue heparin post-operatively, start oral anticoagulant post-operatively when
stable x 3 mo or
● Longer depending on underlying etiology and other comorbidities

12. ●
Complications
● Local: compartment syndrome (see Orthopedic Surgery, OR10) with
prolonged ischemia; requires
●
4-compartment (anterior/lateral/supercial and deep posterior) fasciotomy
●
Heart: risk of arrhythmia, MI, cardiac arrest and death with reperfusion injury
● Kidneys/other organs: renal failure and multi-organ failure due to toxic
metabolites from ischemic muscle, rhabdomyolysis
●
Up to 10% chance of metachronous embolism
● Prognosis
●
• 12-15% mortality rate
● • 5-40% morbidity rate (amputation)

13. Chronic Limb Ischemic/PAD
● Chronic ischemia due to inadequate arterial supply to
meet cellular metabolic demands during walking
(claudication) or at rest (critical limb ischemia)
● Etiology and Risk Factors
● Predominantly due to atherosclerosis; primarily occurs in
the lower extremities
● Conventional risk factors: smoking, DM, hyperlipidemia,
and hypertension
● Predisposing risk factors: advanced age, obesity,
sedentary lifestyle, and PMHx or FMHx PAD/CAD/CVD
●

14. Clinical Features
● Claudication:
● 1. pain with exertion: usually in calves or any exercising
muscle group (within the muscle belly)
● 2. relieved by short rest: less than 5 min and no postural
changes necessary
● 3. reproducible: same distance or time to elicit pain, same
location of pain, same amount of rest to relieve pain
● The presence of the preceding features differentiates
vascular claudication from neurogenic claudication or
MSK pain

15. ● Critical limb ischemia (CLI):
● 1. Includes rest pain, night pain, tissue loss (ulceration or gangrene)
● 2. Pain most commonly over the forefoot/toes, waking person from
sleep, and oen relieved by hanging foot o bed
● 3. Ankle pressure <40 mmHg, toe pressure <30 mmHg, ABI <0.40
● ◆ distal pulses are absent, bruits may be present
● ◆ signs of poor perfusion: hair loss, hypertrophic nails, atrophic
muscle, ulcerations and infections, slow capillary rell, prolonged pallor
with elevation and rubor on dependency, and venous troughing
(Buerger’s sign/Buerger’s angle) (collapse of supercial veins of foot)
● 4. high risk of 1 yr limb amputation and mortality

16. Differential Diagnosis of Lower
Extremity Pain
● Vascular
●
• Atherosclerotic disease
● • Fibromuscular dysplasia
●
• Popliteal entrapment syndrome
● • Venous claudication/hypertension
● Neurogenic
●
• Neurospinal disease (e.g. spinal stenosis)
● • Complex regional pain syndrome
●
• Radiculopathies
● • Diabetic neuropathy
● MSK
●
• Osteoarthritis
● • Rheumatoid arthritis/connective tissue disease
●
• Remote trauma
●

17. Investigations
● Routine blood work, fasting metabolic profile
● • ABI: highest ankle pressure (dorsalis pedis or posterior tibial) for each side divided by highest
brachial pressure.
● • Arterial duplex ultrasound: combines traditional and Doppler ultrasound to visualize blood
vessels and characterize flow and plaques
● • non-invasive: CTA and MRA excellent for large arteries (aorta, iliac, femoral, popliteal) but
may have
● Difficulty with tibial arteries (especially in the presence of disease)
● ■ require IV injection of nephrotoxic contrast (iodinated contrast for CTA, gadolinium for MRA)
● ■ used primarily for planning interventions
● Invasive: arteriography
● ■ superior resolution to CTA/MRA, better for tibial arteries, can be done intraoperatively as
part of intervention
● ■ can be diagnostics and/or therapeutic

19. Treatment
● Goals
● ■ preserve viability (save the leg)
● ■ preserve life (avoid complicated procedures in sick patients)
● ■ improve function and alleviate symptoms
● ■ prevent deterioration and recurrence
● Conservative
● ■ risk factor modication (smoking cessation, glucose control, treatment of HTN
and hyperlipidemia)
● ■ structured exercise program (30-45 min 3x/wk): improves collateral circulation
and muscle oxygenation
● ■ foot care (especially in DM): trim toenails, check between toes for skin breaks,
wear socks and shoes, clear shoes of any debris, keep wounds clean/dry, avoid
trauma and pressure on wounds

20. Pharmacotherapy
● Patients with PAD are at increased risk for CAD and CVD
●
■ antiplatelet agents (e.g. aspirin, clopidogrel)
● ■ statin
●
■ ACEI/ARB
● Surgical
●
■ Indications: severe lifestyle impairment, vocational impairment, critical ischemia
● ■ revascularization
●
◆ endovascular (angioplasty ± stenting)
● ◆ endarterectomy: removal of plaque and repair with patch (usually distal aorta or common/deep
femoral)
● ◆ bypass gra sites: aortofemoral, axillofemoral, femoropopliteal, femoro-tibial, femorofemoral bypass
●
◆ gra choices: saphenous vein graft (reversed or in situ), synthetic [polytetrauoroethylene gra (e.g.
Gore-Tex® or Dacron®)]
●
Amputation: if not anatomically suitable for revascularization, persistent serious infections/gangrene
unremitting rest pain that is poorly controlled with analgesics, medically unt for revascularization

21. ● The ABCDEs of PAD Treatment
● A Anti-plt (ASA, plavix), anti-coagulant (if indicated),
ACEI/ARB
● B Blood pressure control; target sBP <140, β-blocker (if
indicated)
● C Cholesterol management (statin); target LDL <2, smoking
cessation
● D Diabetic control; target HbA1c <7%, Diet/weight
management
● E Exercise (3x/wk, 20 min per session)

22. ● Prognosis
● Claudication: conservative therapy: 60-80%
improve, 20-30% stay the same, 5-10%
deteriorate, 5% will require intervention within 5
yr, <4% will require amputation
● For patients with critical limb ischemia, at 1 yr:
25% risk of mortality (secondary to CVA/MI),
25% risk of amputation, 50% alive with two
limbs, 33% 5 yr survival rate