Vascular Surgery

The arterial wall consists of three concentric layers: innermost to outmost layer

1. Intima - Endotheial cells

- Separated by Internal Elastic Membrane

2. Media - Structural support -Smooth muscle - blood supply = Vasa vasorum

- Separated by External Elastic Membrane

3. Adventita - contains fibroblasts, collagen, and elastic tissue = Strength layer

Upper Extremity

Lower extremity

• ●Atrial fibrillation
• ●Recent myocardial infarction
• ●Aortic atherosclerosis
• ●Large vessel aneurysmal disease (eg, aortic aneurysm, popliteal aneurysm)
• ●Prior lower extremity revascularization (angioplasty/stent, bypass graft)
• ●Risk factors for aortic dissection
• ●Arterial trauma
• ●Deep vein thrombosis (paradoxical embolism)

Without Vascular Disease: Six P's

• Paresthesia
• Pain
• Pallor
• Pulselessness
• Poikilothermia
• Paralysis

With Vascular Disease

• Same symptoms apply but on a different time table

Differential

• Chronic Limb Ischemia
• Compartment Syndrome
• Severe Deep vein Thrombosis
• Vasoconstrictive Disease
• Blue toe Syndrome
• Non-Ischemic pain

Non-Invasive testing

- Arterial-Brachial Index

- Segmentanl Waveforms

Imaging/Invasive diagnostic test

• Angiography - Gold standard

- Increased risk

• CT Angiography
• Carbon Dioxide angiography

- Is not used for arch or cerebral arteriography

• Intravascular US

Thrombolytic Therapy:

• Catheter Directed Thrombolysis
• Mechanical Thrombolysis
• Viable or minimally threatened limbs
• Contraindication

- Absolute: Active bleed, GIB, etc

- Relative: Recent Trauma or Major Non-vascular surgery

- Minor: Liver failure, pregnancy

Open Thrombectomy:

1. Proximal and distal control on the femoral versus below-knee popliteal artery is obtained

2. A longitudinal arteriotomy is created,

3. Thrombectomy balloon(Fogarty) is passed proximally and distally - Clot removed

4. Path or primarly closure of arteriotomy - Non-absorbable suture

TASC A and D lesions: Endovascular therapy is the treatment of choice for type A lesions and surgery is the treatment of choice for type D lesions.

TASC B and C lesions: Endovascular treatment is the preferred treatment for type B lesions and surgery is the preferred treatment for good-risk patients with type C lesions. The patient's comorbidities, fully informed patient preference and the local operator's long-term success rates must be considered when making treatment recommendations for type B and type C lesions.

Indication:

• Unsalvageble extremity 2/2 to vascular disease

- PAD w/wo DM equal more than half of all amputations

• Trauma
• Severe infections
• Local Unresectable tumors
• Frostbite gangrene
• ACS

Perioperative evaluation:

• Medical risk
• Psychological risk

Level of amputation:

• Blood supply

- Physical examination and clinical judgement alone results in healing in 80 percent of BKAs and 90 percent of AKAs

- Palpable Proximal Pulse = Greater than 90%

Above the Knee Amputation(Transfemoral)

• Fish Mouth incision
• Equal anterior and posterior flaps
• Division of Fascia and Muscle,
• Superficial femoral artery and vein identified medially and sutured closed
• Femur transected two finger breaths proximal to skin edge
• Sciatic nerve identified. ligated and allowed to retract
• Flex hip to ensure no tension at skin edge
• Myopexy with muscles from the anterior and posterior compartments
• Close deep fascia
• Close skin

Above the knee(Trans-tibial): Posterior Flap

• Anterior incision extends from medial to lateral, encompassing one-half to two-thirds of the circumference of the leg
• The length of the posterior flap is approximately one-third the circumference of the leg
• Wide posterior flap = Good blood supply but bad dog ears
• Division of anterior and lateral muscle compartments
• Transect tibia and fibula
• Thin out posterior compartment musculature
• Gain hemostasis via suture ligation of anterior tibial, posterior tibial, and peroneal vessels
• Division of peroneal nerves at proximal position to allow retraction
• Coverage of bone with muscle
• Close skin

- Other flap techniques include Skew, Sagittal, Medial, Fish mouth

- ERTL procedure

Post-op Management:

• Wound care
• Stump pain

- Phantom limb

- Neuroma

- Ischemia

• Prevention of flexion contractures

- Knee or hip

- Immobilization of knee joint and Knee exercises

Non-traumatic causes:

• Ischemia-reperfusion injury
• Thrombosis
• Bleeding disorders,
• Vascular disease
• Nephrotic syndrome

Pathophysiology

• Arteriovenous Pressure gradient theory

Common Clinical signs:

• Symptoms

- Pain out of proportion

- Paresthesias

• Exam

- Pain with Passive stretch

- Tense Compartment

- Pallor

- Diminised Sensation

- Muscle Weakness

- Paralysis (late finding)

Diagnosis

• ●ACS delta pressure = diastolic blood pressure ‒ measured compartment pressure

• ●ACS delta pressure <20 to 30 mmHg indicates need for fasciotomy (we use <30 mmHg)

• Elevated serum creatine kinase

• Myoglobinuria

B-Mode imaging:

• Grey scale image useful for evaluating anatomic detail
• Quality of a B-mode image depends upon the strength of the returning sound waves (echoes)

Doppler mode:The shift in sound frequency between the transmitted and received sound waves due to movement of red blood cells is analyzed to generate velocity information.

• Flow toward the transducer is standardized to display as red and flow away from the transducer is blue; the colors are semi-quantitative and do not represent actual arterial or venous flow.

DVT:

• Non-compressible venous segment
• Increased venous diameter: acute thrombus
• Decreased venous diameter: chronic thrombus
• Loss of phasic flow on Valsalva manoeuvre
• Absent colour flow: if completely occlusive
• Increased flow in superficial veins
• Lack of flow augmentation of calf squeeze
• Anechoic thrombus: acute thrombus
• Echogenic thrombus: chronic thrombus

Pseudoaneurysm:

• "Ying-Yang" sign: Due to the turbulent forward and backwards flow
• Treatment

- Open repair

- Thrombin injection

Risk factors: Neuropathy, PVD, Hyperglycemia

• Ischemic Ulcer
• Neuropathic Ulcer
• Poor wound healing

Approach to the Patient:

1. Determining the extent and severity of infection

2. Identifying underlying factors that predispose to and promote infection

3. Assessing the microbial etiology

Superfcial: Cellulitic, ABX Naive

• GPC: Staphylococcus aureus, Streptococcus agalactiae

Deep/Chronic/Recurrent

• Polymicrobial: Enterobacteriaceae, Pseudomonas aeruginosa, and anaerobes.

Systemic/Necrotic/Gangernous

• Anaerobic streptococci, Bacteroides species, and Clostridium species

Determination of Source

• MRSA
• P. aeruginosa
• Resistant Enteric GNR

Managment:

• Wound Care
• Antibiotic Therapy

- Clinical Judgement

• Amputation

Raynaud Syndrome

• Definition: characterized by recurrent episodic vasospasm of the digits precipitated by a stimulus such as environmental cold or emotional stress, manifesting as tricolor changes—white, blue, and red.
• Pathophysiology: It initially produces pallor from cold exposure and vasoconstriction, subsequent cyanosis from hypoxia, and then rubor from the hyperemic response associated with rewarming.
• Prevalence:

- Varies with climate: Damp regions /Young women/Median age 14/Tobacco use

• Evaluation: CBC, ESR, ANA titer, and RA

- A digital hypothermic cold challenge test has been described, with an overall sensitivity and accuracy of approximately 90%.

• Treatment: Avoidance of cold and emotional stimuli

- CCB

- May require aggressive wound care and debridment

Buerger Disease(Thromboangiitis obliterans):

• Epidemiology/Patient Archetype: predominantly affects young male smokers in their 30s, presenting with distal limb ischemia and localized digital gangrene

- eastern European or Japanese heritage

• Pathophysiology/Clinical presentation: is a polyarteritis nodosa vasculitis, with surgical specimens showing involvement of arteries and veins. Occlusive lesions are seen typically in small and medium-sized arteries. It usually occurs in the distal portions of the upper and lower extremities distal to the elbow and knee. Patients frequently have rest pain, ulceration, and, often, digital gangrene.
• Treatment; Tobacco cessation, local wound care

Giant cell arteritis (temporal arteritis)

• Epidemiology

- Age: > great then 55

- Sex: female>Male

• Presentation: is severe pain over the temporal artery that is frequently bilateral, with tenderness and nodularity of the artery.

- 20% develop unilateral blindness

• Diagnosis: Biopsy and elevated ESR
• Treatment: High dose corticosteriods

Takayasu Disease

• Epidemiology

- Age: 3 to 35

- Sex: female>Male

- Race: Asian

• Presentation: Initially with fever, anorexia, and myalgia, followed by a second stage of multiple arterial occlusive symptoms, depending on the location of disease involvement..

- Affects Aorta, Major branches, and PA

• Type

- I: localized to the arch and the arch vessels.

- II: involves the descending thoracic and abdominal aorta

- III: involves the arch vessels and abdominal aorta and its branches

- IV: involves pulmonary arteries

• Treatment: Conservative management

- Surgical and endovascular intervention for stenotic disease is applicable when inflammation is under control

Incidence: Account for 90% of peripheral aneurysms

• The estimated incidence of femoral and popliteal aneurysms is approximately 7/100,000 men and 1/100,000 women

Location:

• Femoral aneurysm located at common femoral with extension into SFA

- 90% have an aortoiliac aneurysm and 60% have bilateral femoral aneurysms

• Popliteal

- 70% have an aortoiliac aneurysm and 50% have bilateral popliteal aneurysms

Diagnosis:

• Clinical

- Widened pulses that are easily palpated

• Imaging

- CT and Ultrasound

- Arteriography - important for surgical planning

Treatment: Should be considered at the time of diagnosis due to possible thromboembolic events

• Femoral

- Resection of the aneurysms with interposition grafts

• Popliteal

- Bypass using autogenous veins, with exclusion of the aneurysm to prevent embolization.

- Covered Stenting

Popliteal Entrapment Syndrome

• Origin: This syndrome is based on an anomalous anatomic relationship between the popliteal artery and surrounding gastrocnemius muscle that may occur during embryonic development.

- Most common variant: is the medial location of the popliteal artery to the normally placed medial head of the gastrocnemius muscle

• Presentation: Young man presenting with caludication like calf pain with no risk factors for PVD

- Age: < 30

- 20% Bilateral

• Diagnosis: MRI

- shows the anomalous relationships between the popliteal artery and gastrocnemius muscle

• Treatment: Surgical intervention

- Removal of the medial gastrocnemius head may be sufficient for patients with minimal arterial disease

- Patients with arterial stenosis or aneurysmal degeneration should be treated with arterial bypass using autogenous veins.

Variation of blood flow

- Visceral Blood flow fluctuation: Catabolic vs Anabolic state

- Mucosal and Submucosal richly supplied

supplies blood to the low-resistance vascular beds of the liver, spleen, and stomach via the hepatic, splenic, and left gastric branches.

Pulsed Doppler demonstrates low-resistance flow in the celiac artery, with high end-diastolic velocities

The superior and inferior mesenteric arteries supply the high-resistance vascular beds of the small intestine and colon. Pulsed Doppler examination reveals high impedance flow with low diastolic velocities in the fasting state

Extrinsic and Intrinsic control Splanchnic blood flow

Intrinsic regulation

Metabolic Pathway

- mucosal ischemia prompts the release of metabolic byproducts,

causing vasodilatation in arteriolar smooth muscle and

preferentially shunting increased blood flow to the intestinal

mucosa

Myogenic Pathway

- Dominates regulation of blood flow in the small intestines,abrupt

decreases in perfusion pressure are sensed by arteriolar baroreceptors,

which respond by decreasing arteriolar wall tension to maintain blood flow

Together, these mechanisms maintain

mucosal perfusion and integrity during periods of relative

ischemia.

Asymptomatic occulsive disease of mesenteric arteries

- Common in Elderly

• Wilson et al15 demonstrate that 17.5% of 553 consecutive patients older than 65 years examined with duplex ultrasonography (DUS) had acritical stenosis of at least one visceral vessel
• Estimated Prevalence: 6% to 10%

AMI

- Decrease Hospitalizations

• AMI in the United States have declined from 9.6 to 6.7 per 100,000 from 1998 to 2010
• Secondary to widespread anticoagulation of at risk population
• female-to-male ratio approximately 3:1

CMI

- Incidence unknown

• CMI account for less than 1 per 100,000 admissions and have been increasing steadily in recent years in the United States
• Despite the high prevalence of individuals with asymptomatic mesenteric arterial occlusive disease, patients usually demonstrate involvement of two or more mesenteric vessels before symptoms arise owing to the development of extensive collateralization over time.

Chronic

Athersclerotic disease

- Risk factors

• history of smoking, hypertension,and hyperlipidemia.

- Concomitant disease

• Coronary, renal, Aortoiliac, etc

- Vasculitis and Inflammatory conditions

• Lupus, Buerger's, XRT

- Median arcuate ligament syndrom

• Symptoms

- Most common cause of AMI

• 40 to 50 percent of cases

- Proximal source

• mural thrombus that develops in patients with atrial tachyarrhythmias, myocardial infarction, cardiomyopathy, structural heart defects, cardiac tumors, endocarditis, proximal aneursym

- SMA

• Most common location: size and angle
• Distal to middle colic artery

Acute

- second most common cause

• 20% t0 45% of cases

- Preexisting atherosclerotic plaques

• segment of artery is usually its origin at the level of the aorta

- Mortality

• acute thrombosis of a mesenteric artery was 77.4%, compared with 54.1% for patients with acute arterial embolism
• Involment of large bowel segments

Nonocculsive Mesenteric Ischemia

Definition: Impaired intestinal perfusion in the absence of thromboembolic occlusion

• 5% to 15% of cases

Causes:

Low Flow state

Hemodialysis Correlation:

- reported incidence rates more than 40 times greater among patients on hemodialysis compared with the general population

- Hyperviscosity and Hypotension

• EPO
• Hypotension during dialysis has been implicated as the most important and immediate precipitating risk factor for development of NOMI

Mesentric Venous Thrombosis

constitutes 5% to 15% of all cases of mesenteric

ischemia

Anatomy

- Involvement is usually limited to the superior

mesenteric vein, but the inferior mesenteric, splenic, and

portal veins can also be involved

Primary = Idiopathic

Secondary: Causality

- 90% of cases

- Three Major catergories

• Direct injury
• Venous Stasis
• Congestion

- Dictates pattern of thrombosis

- Insidious process

Acute

Abdominal pain

HPI:

- Sudden onset

- Dramatic and Severe pain

- Pain out of propoition to PE

Associated symptoms:

- Early stage

• Hyperactive BS
• Limited pain to palpation

- Late stage

• Diminished BS
• Guarding and rebound tenderness

MVT and NOMI

Chronic

CC:

Abdominal Pain

HPI:

- Dull and Crampy

- Post-Prandial

• 15 to 45 minutes
• Size of meal

- Progressive weight loss

Physical Exam: Nonspecfic

Non-invasive

Duplex Ultrasound

- Diverse application

- Defining sonographic mesenteric stenosis

• Lack of flow or a PSV in the SMA of greater than 275 cm/s
• Lack of flow or a PSV of greater than 200 cm/s in the celiac trunk
• Was a reliable indicator of 70% or greater angiographic stenosis
• IMA not generally asscessed

- Limitations

- DUS is also the primary imaging modality used for surveillance after both bypass and stenting

CT Scan

AMI Radiological findings:

- thickening, dilatation, and attenuation, Pneumatosis intestinalis, portal venous air, mesenteric edema, and ascites

- Arterial Phase:

• contrast infusion, the mesenteric vessels can be evaluated for thrombosis, embolus, dissection, and aneurysm

MVT Radiological finding:

- Venous Engorgement

- "Target sign"

• seen in the superior mesenteric vein, with thrombus in the center of the lumen and surrounding contrast-enhanced blood flow peripherally

Invasive

Angiography

Gastic tonometry

Medicinal

CMI:

- Risk factor Modification

- Nutritional optimization

- Anti-PLT therapy?

AMI:

- Resuscitation

- Antibiotics

• Bacterial translocation

Endovascular

AMI:

has been slower, and a decline in the number of open revascularizations

has not been observed

CMI:

Balloon angioplasty with stenting has surpassed open surgery as the dominant method of revascularization for CMI, and an endovascular approach is now generally accepted as primary therapy

Mesenteric Stenting with Ballon

Angioplasty:

- Efficacy when compared to open

• Patient selection
• Increased re-stenosis and

reintervention

• No RCT for comparison

- Techianical Considerations

• Access: femoral vs Brachial
• Lesion selection: short, focal stenosis/occlusions with less calcification and thrombus

Retrograde Mesenteric Stenting

- Hybrid procedure

- Shows promise in treatment of AMI

• Mortality was 17% for the patients who underwent retrograde stenting compared with 100% for the antegrade stenting group and 80% for those who underwent surgical bypass.

Limitations

- Restenosis

- Re-intervention

- Distal Emboli

• 8% chance

- Anatomical Compromise

Surgical

Applicable for both AMI and CMI

SMA Embolectomy

- Transaortic Endarterectomy

- Antegrade Mesenteric Bypass

-Retrograde Mesenteric Bypass.

Vascular - Arterial

Anatomy and exposure of Mesenteric vessels

Questions?

Mesenteric Ischemia

Physiology

Leads vasoconstriction of mesenteric vessels, reduction in portal venous pressure, and venodilation

Mesenteric vasoconstriction:

• Direct action of AT-II

The celiac artery low-resistance flow pattern is not dependent on food intake

Fasting:

- Bowel empty

- Vasoconstriction

Fed:

- Bowel full

- Vasodilation

- Doubling of EDV

Compartment Syndrome

Gut circulation regulated through vasoconstriction and relaxation of arterial smooth muscle

Clinical signs: Most commonly affected

• Early: loss of sensation between the first and second toes and weakness of foot dorsiflexion
• Late: Foot drop, Claw foot, and Deep Peroneal nerve dysfunction

Clinical Signs:

• Plantar hypesthesia,
• Weakness of toe flexion
• Pain with passive extension of the toes.

Objectives:

1. Anatomy

2. Physiology

3. Epidemiology

4. Differntiation between chronic and acute ischemia

5. Treatment Modalities

Operative vs Endovascular intervention

Least Likely to see in ACS

Lesions

Ultrasound Use in Diagnosis of Vascular disease

Mechansim of Action: Real-time ultrasonography uses reflected sound waves (echoes) to produce images and assess blood velocity.

Endovascular

Operative

Less than 5 mm

- Angioplasty

- Stenting

Bypass procedures

• Fem-Fem
• Fem-Pop
• Aortobifemoral

Amputation of Lower Extremity

Anatomy/Histology

Epidemiology

Atherosclertoic Stages:

1 - Foam cells

2- SM cell proliferation

Treatment

Management

Category IIb limbs are salvageable if treated as an emergency.

Category III limbs have irreversible ischemia and are not salvageable.

Category: I limbs are viable and not immediately threatened.

Category IIa limbs are threatened but salvageable if treated.

AMI

CMI

Diabetic Foot infections

Acute Limb Ischemia

Pathophysiology

Arterial Thrombus

Embolism

Diagnostic Evaluation

Clinical Presentation

CC:

-Insidous onset

- Critically ill

Physical Exam:

Nausea, vomiting, diarrhea,

emptying symptoms, and distention

1. Anatomy/Histology

2 Definition/Prevention/Etiology

3. Presentation

4. Diagnosis

5 . Operative/Non-operative treatment

"Food Fear"

Elderly woman

• 70%

Risk Factors

Diagnosis

Nonatherosclerotic Occlusive Diseases

External Iliac

artery plaque

Common Iliac Stent Thrombosis

Sharp systolic

upstroke

Reversal of flow in early diastole

Low-amplitude forward flow throughout diastole

With obstructive disease, the initial feature lost is the reversal of the flow component, leading to multiphasic (previously called biphasic) flow. Severe disease leads to blunting of the arterial waveform, with decreased amplitude and decreased slope of the upstroke.

A decrease in pressure of 20 to 30 mm Hg between adjacent segments is indicative of a significant lesion.

Large-Vessel Vasculitis

Defintion/Prevention/Etiology

Risk Factors

Etiology

Femoral and Popliteal Aneurysms

Presentation

Factors:

• Time
• Location
• Collateral flow