Vascular

Question 1

What are common risk factors for the development of acute arterial thrombosis?

Answer 1

• RIsks: male, old, not-white, FHx (vascular dz, stroke, MI), HTN, DM, smoking - atherosclerosis leading to embo
• Causes: thrombosis from IV cath, vascular dmg d/t trauma, occlusion from arterial dissection, a fib creates myocardial thrombi, aneurysms serve as a nidus for thrombi, hypercoagulable states, IVDU
• Occlusion superimposed on an underlying arterial abnormality such as a stenotic arterial plaque or an arterial aneurysm
• Precipitated by hypotension or hypovolemia
• APLA

Question 2

What are the characteristic history and physical findings associated with acute arterial thrombosis

Answer 2

• Hx: vascular interventions, chronic vascular dz, a fib, embolic hx (strokes), aortic dissection (limb ischemia +/- visceral malperfusion), hypotension, trauma, sx duration; 6 Ps
• PE: multifocal atherosclerosis, chronic limb ischemia, motor/sens exam
  
  • handheld Doppler: assess arterial circulation to the extremity
  • auscultation and EKG/rhythm strip: atrial fibrillation
  • tissue loss; sx of less severe w/ chronic pts d/t formation of collaterals
• Tx: dependent on motor and sensory exam: determines urgency/tx
  
  • motor deficits - immediate revascularization
  • no or mild sensory loss - percutaneous thrombolysis

Question 3

What is the diagnostic algorithm for evaluation and treatment of acute arterial thrombosis?

Answer 3

• Therapeutic heparin initially (80 u/kg, 17 u/kg/hr)
• CTA to define occlusion
• Class I (pain) or IIA (mild numbness) ischemia - angiography - percutaneous thrombolysis
• Class IIB ischemia (rest pain, weakness, loss of signals) - OR - mech thrombolysis, thrombo/embolectomy, bypass
  
  • ​radiolucent table - endovascular intervention
  • inflow source (femoral or axillary artery) - bypass option
  • completion angiography mandatory
  • consider fasciotomy based on time of ischemia (6 hrs)
• ​Class III ischemia - irreversible - amputation
• ​Postop: echo +/- CTAs chest/abd/pelvis to find source

Question 4

Discuss the diagnostic algorithm for evaluating a patient with arterial embolic disease.

Answer 4

• thorough cardiovascular H&P - causes of embolism, and location
• EKG: rhythm, signs of ischemia
• asymmetric vascular exam, abrupt sx, neg ischemic hx - embolism
• embolus cannot be localized by PE - duplex, CTA, and/or angiography
• occlusion at popliteal artery - exam for aneurysm (duplex)
  
  • not amenable to femoral embolectomy
• no axillary pulse w/ upper extremity ischemia - imaging prior to exploration,
  
  • emboli to the axillary artery are unusual
  • blind proximal embolectomy - retrograde embo of vertebral artery

Question 5

An elderly woman presents 6 hours after the abrupt onset of acute right leg pain, paresthesias, and paralysis of the foot at the level of the ankle. She has a history of atrial fibrillation. Her only medication is aspirin. Her physical examination is remarkable for the absence of a right femoral pulse, and more distal pulses are also absent. Left leg pulses are normal. Arterial Doppler signals are absent at the level of the ankle; venous signals are present. The foot is numb and has some decrease in mobility. Describe the management of the patient’s leg ischemia.

Answer 5

• A heparin bolus/drip should be given immediately - prevent distal propagation
• Class IIB ischemia - emergency operation should be scheduled; CTA if time, but not necessary
• Abdomen, R leg, and L groin prepped (inflow if R femoral not established)
• Explore groin through longitudinal R skin incision and expose artery
• If artery is relatively free from atherosclerosis - transverse arteriotomy on the CFA low enough to access the origin of both the superficial and profunda femoris arteries.
  
  • If considerable plaque is present in the CFA - longitudinal arteriotomy extending to the femoral bifurcation is performed, and subsequent patch closure will be required.
• Distal thromboembolectomy performed first to clear the outflow tract, followed by proximal thrombectomy
• Completion angiography unless posterior tibial and dorsalis pedis pulses are readily palpable after embolectomy
• If good proximal inflow not achieved - proximal angiography or conversion to femoral-femoral bypass contralateral groin
• On the basis of degree and duration of ischemia before revascularization - ppx 4 compartment fasciotomy
  
  • ​Superficial and deep posterior (through medial), anterior, lateral

Question 6

After management of an embolus to an extremity, what measures can be taken to prevent future emboli?

Answer 6

• imaging: echo, CTA of the chest, abdomen and pelvis - identify the source
• cardiac events - therapeutic anticoagulation
  
  • lifelong basis unless substantial contraindications - 3 to 6% annual risk of recurrence
• if an aneurysm is found - treat
• proximal ulcerated lesions of the aorta - no empirically anticoagulated - may increase further embolic events
  
  • treated with antiplatelet agents
  • treatment of ulcerated lesions in the proximal arterial tree is individualized

Question 7

A patient under treatment for acute left deep venous thrombosis (DVT) develops the abrupt onset of right leg pain, and the previously palpable right femoral and distal pulses are no longer palpable. What has occurred, and what should be done?

Answer 7

Paradoxical embolus: pre-existing ASD or PFO, embo to R iliac artery

• Hx of subacute PEs - pulmonary HTN - elevated right heart pressure - right-to-left shunt
• Already anticoagulated for the DVT
• OR for embolectomy (class IIB) - right femoral cutdown
• IVC filter - prevent future emboli for thromboembolization while anticoagulated
• CTA chest - eval for PE (though this does not change mgmt)
• TEE - confirm the diagnosis ASD - bubble study; may need future closure

Question 8

A 65-year-old male presents with a 12-hour history of pain and coolness in the left leg. On physical examination, the leg is cold, insensate, and paralyzed leg. He has a palpable femoral pulse but no distal pulses. ECG demonstrates new onset atrial fibrillation. What will you do?

Answer 8

• Ensure CV stability, rule out MI (EKG, troponin), cardiac rate control (B-block), anticoagulation (heparin)
• Class III - dead - cannot salvage
• Level of ampx - depends on N/V exam level, postop fx
  
  • AKA: lower morbidity, higher mortality
  • BKA - 4 finger breadths below tuberosity, fibula 1-2 cm shortness than tibia, don’t close too tight
• complications with amputation - fistula, compartment syndrome

Question 9

A 70-year-old female presents with a cool leg and weak dorsiflexion of the foot, which has been ongoing for 3 hours. She recently underwent an intraocular lens implantation. She has no femoral pulse or distal pulses in the affected leg. What will you do?

Answer 9

• H&P: CV hx, EKG, troponin
• ABI, doppler, heparin therapy, CTA if no delay
• Weakness means threatened limb - IIB
• Do embolectomy
• Thrombolysis contraindicated d/t eye surgery
• Do diagnostic and completion angiogram

Question 10

A 75-year-old male is in the CCU after an STEMI (segment elevation myocardial infarction) and has an IABP (intra-aortic balloon counter-pulsation) in his right leg. The right leg has been cool for 4 hours. The right femoral and popliteal pulses are weakly palpable, but pedal pulses are absent. Motor function and sensation are intact. What will you do?

Answer 10

• Examine the contralateral leg and determine if this is a unilateral phenomenon
• Determine the HD status of the pt and need for the IABP
• Following options depends on findings
  
  • move IABP to contralateral leg
  • heparinization and obs
  • femoral embolectomy

Question 11

A 76-year-old male had a right femoro-popliteal bypass two years ago, He now presents with a 4-hour history of coolness and paresthesias in the right leg. He has a palpable femoral pulse but absent distal pulses. Motor function is very weak. What will you do?

Answer 11

• IIB - requires immediate intervention, embolectomy
• Likely intimal hyperplasia or atherosclerosis in this time period
  
  • early - technical failure at anastomosis
  • late - atherosclerosis
• Tx depends: location, length, availability of autolagous vein
• Short lesions - vein patch angioplasty
• Stenosis at site or atherosclerosis - vein graft extension
• Open surgery favored over endovasc or conservative

Question 12

You are placing an implantable venous access device, and shortly after your dilation cannula is placed, a larger amount of air is sucked into the venous circulation. What is the appropriate treatment? What steps can be taken to prevent this event?

Answer 12

• Air embolization during central venous cannulation and catheter placement - sudden respiratory distress, dyspnea, chest pain, dizziness or LoC, HD collapse, tachypnea/cardia, inc JVP
• ABC, O2, L lateral decub and Trendelenburg position
• CBC, BMP, CPK, troponin, BNP, ABG, CXR, EKG, echo, CT PE
• Bernoulli’s principle of fluid dynamics (↑ flow = ↓ pressure & ↓ flow = ↑ pressure)
• Hyperbaric oxygen ASAP, can suction air from RV through CVL
• Prevent by having patient in Trendelenburg, occluding lines during placement

Question 13

You are called in consultation to evaluate a patient who has been recently diagnosed with left-sided breast cancer. Neo-adjuvant chemo/radiation has been recommended by the oncology team. What considerations will go into your planning with regard to location of the catheter?

Answer 13

• Effects of radiation therapy at catheter and wound sites.
• Signs and symptoms of central venous stenosis and impact on catheter/port placement.
• Lymphedema and how risks of DVT may influence the site chosen.

Question 14

You are called to the PACU to evaluate a patient in whom you have just placed a tunneled venous access device. The post-procedure chest radiograph demonstrates a port in the right chest region with the catheter tracking underneath the right clavicle, crossing the midline and descending down the left side of the mediastinum. What is your initial work-up? What is the most appropriate treatment?

Answer 14

• Inadvertent arterial cannulation - bright blood, pulsatile backflow, hematoma
• Likely subclavian artery - check HDS and neurovasc exam
• Morbidity: hematoma, pseudoaneurysm, thromboembolism
• Workup: ABG from cath, US/CTA to determine location, labs, know cannula sheath size
• Tx: leave in place and vasc consult
  
  • Leave in - risk thrombus and subsequent stroke or peripheral embolism
  • Remove - risk exsanguination, pseudoaneurysm (tx w/ thrombin or coil), AVF
• Methods of repairing iatrogenic arterial injury: open repair or percutaneous coil (if distal to vertebral)
  
  • ​Remove and apply pressure only feasable for femoral catheter
  • Needs good neuro exam postop

Question 15

You are called to the emergency department to evaluate a patient who is known to the surgical oncology service. Upon arrival, you find a 62-year-old female who is tachycardic to 114 beats per minute with a blood pressure of 91/63 mmHg. The nurse alerts you to the fact that the patient has a temperature of 102.1°F and is diaphoretic. On your exam, you note erythema overlying a subcutaneous port in the right chest. How would you manage this patient?

Answer 15

• Line sepsis
• Cxs from line and blood, fluid resuscitation, abx
• Coagulase-negative staphylococcus coverage
• Removal of the subcutaneous port/catheter

Question 16

A patient with an indwelling subclavian central venous catheter presents with ipsilateral arm swelling and pain. What is your approach to making a diagnosis in this situation?

Answer 16

• Obtain a venous duplex ultrasound of the upper extremity to assess for deep vein thrombosis (DVT).
• Recognize the need to remove the catheter.
• Initiate systemic anti-coagulation to prevent clot propagation.
• Recognize the need to rule out PE

Question 17

A patient presents with cellulitis at the site of peripherally inserted central line catheter and high grade fever. What is your initial treatment plan?

Answer 17

• Immediately initiate antibiotics with a spectrum effective against coagulase-negative staphylococcus, which has a high rate of resistance to methicillin.
• Urgent need to remove the catheter.

Question 18

A patient presents with a tunneled central venous catheter which is utilized for chronic parenteral nutrition. The catheter is difficult to flush or aspirate. What are the possible causes of catheter occlusion, and what is your initial plan to determine if catheter patency can be re-established?

Answer 18

• Causes of catheter occlusion include fibrin sheath formation around the catheter, intraluminal or mural thrombus formation, and venous endothelial injury.
• Patency may be re-established by injecting a fibrinolytic agent [e.g., alteplase (tissue plasminogen activator {t-PA}, 0.5-2 mg)].

Question 19

A 65-year-old female with Stage IV chronic kidney disease (CKD) secondary to Type II non-insulin-dependent diabetes mellitus (NIDDM) and hypertension is referred for evaluation for AV access for hemodialysis. What is your approach?

Answer 19

• Dominant versus non-dominant extremity
• History of prior subclavian catheters, PICC lines, ports, and pacemakers
• Duplex ultrasound as an adjunct to physical examination - mark, vein map
• Determine timing of autogenous AV fistula versus prosthetic AV graft

Question 20

A 50-year-old obese male with Stage V CKD secondary to hypertension presents two and a half months post left brachiocephalic AV fistula. The nephrologist is asking whether fistula can be used to initiate dialysis. How do you decide when fistula is mature and can be used?

Answer 20

• Rule of 6’s: > 6mm in diameter, < 6 mm deep, > 600 ml/min flow
• Duplex ultrasound - flow volumes
• Fistulagram - if cannot get good flow volumes

Question 21

A 70-year-old male with end-stage renal disease (ESRD) secondary to Type II DM on chronic hemodialysis via IJ tunneled catheter presents with a cool, painful left hand two weeks post left brachiocephalic AV fistula. He has a history of coronary artery disease (CAD) and with an MI and PCI with drug eluting stent 2 years earlier. What is your diagnostic and therapeutic approach?

Answer 21

• Likely 2/2 steal syndrome
• Diagnosis of hand ischemia: clinical - 5 P’s
  
  • Rest pain, ischemia, ulcerations, necrosis, loss of ADLs
  • Occlude fistula and see if resolution of sx
• Imaging: angiography
• Surgery: ligation, banding, DRIL (distal revascularization)

Question 22

The prevalence of CKD is around…

Answer 22

7%

Question 23

Superficial veins of the upper extremity used for vascular access in dialysis.

Answer 23

cephalic, basilic, median antecubital

Question 24

Central veins used in vascular access for dialysis

Answer 24

axillary or internal jugular

Question 25

Lower extremity veins used in vascular access for dialysis

Answer 25

Saphenous or common femoral

Question 26

Temporary dialysis access preferred location and other locations

Answer 26

Preferred location – contralateral internal jugular vein May also use ipsilateral internal jugular vein, contralateral subclavian vein or ipsilateral subclavian vein if needed. Femoral veins should be used in bed-bound patients only.

Question 27

Be able to discuss the physiologic effects of permanent AV anastomosis placement on a patient’s hemodynamics and distal extremity. What are the symptoms of steal syndrome?

Answer 27

* AV anastomoses can cause steal syndrome in the distal extremity. * Steal physiology is seen in 75-90% of patients. * Only 1-6% are symptomatic. * Patients may experience pain or even develop tissue loss.

Question 28

Have a broad differential: what are 5 categories of renal disease?

Answer 28

* Pre-renal – Due to decreased renal perfusion * Renal vascular disease * Glomerular disease – Nephrotic and nephritic syndromes * Tubular and interstitial disease – Including PKD * Post-renal – Due to obstruction

Question 29

Reversible causes of renal failure

Answer 29

* Decreased renal perfusion * Nephrotoxic drugs * Obstruction

Question 30

Physiological targets for renal protection

Answer 30

* Blood pressure * Reduction in urinary protein excretion * Smoking cessation * Glycemic control * Treatment of chronic metabolic acidosis with bicarbonate

Question 31

Patients with acute renal failure will need what type of vascular access?

Answer 31

a temporary dialysis catheter

Question 32

If expected need for dialysis is less than 3 weeks, what type of catheter can be placed for vascular access for dialysis?

Answer 32

a non-cuffed catheter may be placed

Question 33

If dialysis is needed for more than 3 weeks, what type of catheter should be used for vascular access for dialysis?

Answer 33

a cuffed, tunneled central venous catheter should be used

Question 34

In terms of vascular access what is the hierarchy of preferred access?

Answer 34

Fistulas are preferred to grafts, grafts are preferred to the use of long-term catheters. Peritoneal dialysis is an excellent modality, in selected patients.

Question 35

Why is the preferred location for temporary dialysis access the IJV rather than SCV?

Answer 35

Prevent the development of subclavian stenosis

Question 36

What is the preferred site for AV access for dialysis?

Answer 36

nondominant upper extremity is the preferred site for permanent AV access

Question 37

What imaging should be used in all possible permanent dialysis catheter patients to evaluate the veins for venous access?

Answer 37

duplex ultrasound

Question 38

Discussions regarding AV access should begin when the patient reaches CKD ?

Answer 38

4

Question 39

The National Kidney Foundation-Kidney Dialysis Outcomes Quality Initiative (NKF-KDOQI) clinical practice guidelines for placement of permanent autogenous AV access in patients with CKD:

Answer 39

* Access preferred **distally** in the upper extremities. * Fistulas \> grafts \> long-term catheters. * Fistula sites in order of preference – wrist, forearm, arm * Distal fistulas have superior patency rates and a lower risk for complications.

Question 40

How do you define dialysis catheter dysfunction?

Answer 40

decreased flow

Question 41

How do you treat dialysis catheter dysfunction?

Answer 41

repositioning, thrombolytics, replacement

Question 42

What are AV access complications?

Answer 42

extremity edema, extremity ischemia, graft rupture, stenosis, thrombosis, and infection

Question 43

How do you treat severe edema or extremity ischemia as it relates to AV fistulas?

Answer 43

surgical revision

Question 44

How do you treat AV graft stenosis?

Answer 44

Stenosis can be treated with angioplasty, stenting, or surgical revision

Question 45

How do you treat AV graft thrombosis?

Answer 45

Thrombosis can be treated with angioplasty or surgical thrombectomy

Question 46

How do you treat superficial infections in AV grafts?

Answer 46

Superficial infections should be treated with broad-spectrum antibiotics and incision and drainage. Infected graft material should be excised.

Question 47

Describe an appropriate short- and long-term follow-up plan for a patient after permanent AV access placement and when further interventions are needed.

Answer 47

The AV access should be evaluated with a duplex ultrasound after 6 weeks. The dialysis catheter should not be removed until the AV access has been used successfully in three visits. Further interventions are needed if flows are insufficient or if any complications occur.

Question 48

Discuss the patency rates of permanent autogenous and prosthetic AV access and the primary reasons for vascular access failure.

Answer 48

* Primary patency rates for autogenous at 2 years – 55% * Primary patency rates for prosthetic at 2 years – 40% * Secondary patency rates for autogenous at 2 years – 63% * Secondary patency rates for prosthetic at 2 years – 60% * Risk factors for primary failure of fistulas include increased age, obesity, nonwhite ethnicity, female gender, diabetes, coronary artery disease, and peripheral artery disease.