Vascular Disease

Question 1

Atherosclerosis is a generalized INFLAMMATORY disorder of the arterial system associated with ENDOTHELIAL DYSFUNCTION. Name the common pathophysiological causes of atherosclerosis. (4) (i.e. not clinical RF)

Answer 1

1. Endothelial damage - caused by hemodynamic shear stress 2. Inflammation - caused by chronic infections 3. Thrombosis - caused by hypercoagulable state 4. Intimal damage - caused by oxidized LDL

Question 2

What are the layers of the artery?

Answer 2

Outermost externa/adventitia: connective tissue made of collagen Middle media: smooth muscle and elastic tissue Innermost intima: endothelial cells

Question 3

What is Virchow’s triad?

Answer 3

1. Endothelial damage 2. Stasis 3. Hypercoagulability Describes the 3 broad categories that contribute to thrombosis.

Question 4

How does LDL contribute to the formation of atherosclerosis?

Answer 4

They move through the endothelium, into the intimal layer where they are trapped and become proinflammatory.

Question 5

Name the risk factors for atherosclerosis? (10)

Answer 5

Modifiable: Cigarette smoking Abdominal obesity HTN Insulin resistance Elevated LDL Reduced HDL Possibly modifiable - depending on etiology: Proinflammatory state Prothrombotic state Non-modifiable: Aging Family hx of premature CAD

Question 6

What are two of the best predictors for morbidity and mortality after vascular surgery?

Answer 6

Low serum albumin and high ASA classification. Others included: esophageal varicies, DNR status, ventilatory dependent, emergency surgery, elevated CR

Question 7

What clinical syndromes are associated with aortic atherosclerosis? (2 + 3)

Answer 7

AAA Aortic dissection Peripheral atheromembolism Penetrating aortic ulcer Intramural hematoma

Question 8

Define peripheral arterial disease (PAD).

Answer 8

Atherosclerosis affecting the limbs

Question 9

Ankle-brachial index is the best screen for PAD. Define ratios for normal, vessel hardening, PAD, and critical.

Answer 9

Greater than 1.2 = vessel hardening 1-1.2 = normal Less than 0.9 = abnormal Less than 0.4 = critical, limb threatening ischemia

Question 10

How is the ABI measured?

Answer 10

Patient must be supine. SBP for brachial artery SBP for posterior tibial and dorsal pedis - high SBP taken SBP ankle artery : SBP brachial artery

Question 11

What is the standard method for diagnosing PAD?

Answer 11

Catheter based angiography. Note: MR- and CT- angiography are becoming more common.

Question 12

Risk of AAA rupture is very low below which diameter?

Answer 12

Less than or equal to 4cm

Question 13

Between 4-5cm a AAA should be monitored by US every how many months?

Answer 13

6mos

Question 14

T/F: Baseline Hgb is independently associated with AAA size and reduced longterm survival following intervention.

Answer 14

True. This allows for additional risk stratification.

Question 15

Continuation of which of the following chronic medical therapies may reduce perioperative m&m following vascular sx: Beta blockers ACEi Statins ASA Hypoglycemics and insulin

Answer 15

ALL: Beta blockers ACEi Statins ASA Hypoglycemics and insulin

Question 16

Name 4 benefits to starting statins preoperatively and continuing them post op, WRT vascular sx.

Answer 16

1. Mortality - patients who received statins were less likely to die 2. Decreased cardiac peri-op morbidity - patients in whom statins were stopped in the 4 day peri-op period were at increased cardiac risk. 3. Improved graft patency 4. Improved limb salvage, decreased amputation rate

Question 17

Chronic ASA and other anti-inflammatory drugs may stop the progression of atherosclerosis and CV events. What are the general recommendations regarding ASA and clopidogrel use in peri-op period (assuming no stent)?

Answer 17

Clopidogrel - does not increase risk of mjr bleeding if restarted 48H after PV sx ASA - take until day of sx for carotid and PV sx. Individualized for larger (ex aortic) sx.

Question 18

Absence of SEVERE CAD can be predicted (96% PPV) in patients without these 4 clinical RF.

Answer 18

Diabetes CHF Prior angina Previous MI Take home point: Clinical RF predict severity of CAD

Question 19

Describe how remote vs recent PCI is associated with cardiac morbidity following non-cardiac sx.

Answer 19

Remote - May be protective Less than 6 weeks - Increased risk Note that PCI done to reduce cardiac risk does NOT reduce periop MI

Question 20

What are the current anti-platelet guidelines following stent placement?

Answer 20

ASA 325mg/d and clopidogrel 75mg/d BMS: 1 month DES: 12 months Then ASA indefinitely

Question 21

What are the current guidelines for ASA and clopidogrel if the patient has a stent?

Answer 21

Continue ASA in ALL patients with stents. Discontinue clopidogrel for as short a period as possible. Specifically, holding for 8 days may not be necessary.

Question 22

What is an early periop MI?

Answer 22

Acute non-surgical MI. Most likely due to coronary occlusion by plaque rupture or thrombosis.

Question 23

What is a late periop MI?

Answer 23

Most likely demand MI in setting of fixed coronary stenosis. Associated findings: increased HR, absence of CP, prolonged period of STD prior to MI.

Question 24

Post op, what could increase O2 demand? Decrease O2 supply?

Answer 24

increase O2 demand Increased HR or BP secondary to pain Decrease O2 supply Anemia Hypotension.

Question 25

Draw the algorithm for cardiac evaluation for non-cardiac sx

Answer 25

Question 26

What are the “Major” perioperative cardiovascular RF as defined by the AHA/ACC? (6)

Answer 26

Acute MI (less than 7 d)

Recent MI (7-30 d)

Unstable angina

Decompensated CHF

Severe valvular dx

Significant dysrhythmias

Question 27

What are the “Internediate” perioperative cardiovascular RF as defined by the AHA/ACC? (5)

Answer 27

Hx of ischemic HD (ex. angina, prior MI)

CHF - hx of, or compensated

DM

Renal insufficiency

CVD

Question 29

What are the “Minor” perioperative cardiovascular RF as defined by the AHA/ACC? (4)

Answer 29

Age > 70

Adn ECG

Rhythm other than sinus

Unconrtolled systemic HTN

Question 30

Should patients with known CAD undergo coronary revascularization prior to vacular sx?

Answer 30

There was no benefit to revasculartization (vs. medical therpay) in patients in whom revascularization was not otherwise indicated for ACS (ex. left main dx, EF less than 20%)

Medical therapy = beta blockers, ASA, statins

Question 31

If coronary revascularization is indiciated prior to vacular sx, which method (sx vs PCI) is associated with better outcomes?

Answer 31

Surgical revascularization, i.e. CABG

Question 32

Assuming stents are not also inserted, what is the safe time interval between coronary revasculartization and vacular sx?

Answer 32

PCI = 2 weeks

Surgical revascularization = 4-6 weeks

Question 33

What is the treatment of HIT?

Answer 33

Stop heparin

Full anticoagulation with direct thrombin inhibitor

3 weeks of warfarin rx: note warfin therapy alone can diminish protein c and s and promote thrombosis