Vascular Disorders Flashcards

Question

A patient presents with intermittent claudication. If he has an arterial occlusion in his lower extremity, where will it most likely be found?

Answer 1

Superficial femoral artery in the adductor hiatus is the most common location of occlusive disease in the lower extremity.

Answer 2

ABI and Doppler to detect stenotic areas and locate the level of the occlusion. Normal ABI is 0.9-1.1. In mild claudication, ABI is 0.6-0.8 and indicates single level disease. Severe claudicationi ABI is \< 0.5 and indicates multilevel disease. An ABI \< 0.3 is typically indicative of rest pain or tissue loss.

Answer 3

Typically as high as the cuff is inflated, this is because their vessels have become calcified from atherosclerotic disease and are now non-compressible.

Answer 4

Triphasic = good vessels with phase of rapid systolic flow, reversal flow due to elastic recoil and finally a diastolic outflow phase. Diphasic = loss of the reverse flow, indicating decreased elasticity of the vessels due to atherosclerosis, can also be normal. Monophasic = severe disease with no changes.

Answer 5

Non-operatively with lifestyle modification (exercise, smoking cessation, lipid-lowering drugs, diet and weight loss). With this approach 1/3 get better, 1/3 stay the same and 1/3 get worse. Revascularization surgery is really only done in patients without critical limb ischemia when the claudication is an impairment to their activities of daily living. Note that you should not order an arteriogram unless you are actually planning for surgery due to the inherent risks of the test.

Answer 6

Claudication, impotence and pulselessness indicating aortoiliac occlusive disease.

Answer 7

Aortoiliace occlusive disease, impairment of ADLs, pt is otherwise healthy, ulceration in a patient w/insufficient blood supply to heal it and rest pain.

Answer 8

Ankle SBP \> 65 in non-diabetics and \> 90 in diabetics = likely will heal. Ankle SBP 55-65 in non-diabetics and 80-90 in diabetics = probable. Ankle SBP \< 55 in non-diabetics and \< 80 in diabetics = unlikely.

Answer 9

Arteriogram to assess the different levels of occlusion. This will tell you if the patient has inflow disease (iliac occlusive disease) or outflow disease (single or multiple occlusions in the superficial femora, popliteal and distal arteries).

Answer 10

Fem-pop bypass. Distally you whould give preference to reconstitution with the femoral, anterior or posterior tibial arteries. Peroneal artery should only be used if the tibials are occluded.

Answer 11

Above the knee (saphenous or PTFE), below-knee (saphenous way better than PTFE) and infrapopliteal (saphenous way better than PTFE)

Answer 12

Duplex u/s graft examination for stenosis, aspirin, lipid-lowering agents and education about foot care if needed. Note that these patients have atherosclerotic disease and are most likely to die from CAD.

Answer 13

PTA if single, short-segment iliac stenosis. Aortobifemoral bypass if bilateral loss of femoral pulses. If patient has poor risk factors for a transabdominal approach, an axillofemoral bypass graft may be considered. If the other femoral artery were patent, a femorofemoral bypass can be performed.

Answer 14

If the patient is expected to live \> 2 years and has a viable autologous graft, they should get bypass because long-term success rates are better.

Answer 15

Aside from high risk during anesthesia induction, hemorrhage or stress, clamping the aorta increases the afterload on the heart (anticipate this by giving afterload reducing agents before clamping) and unclamping the aorta has risk of bleeding from the graft, hypotension from sudden decrease in afterload and subsequent increase in CO. In addition to this, the LE static blood becomes acidotic and hyperkalemic, which can adversely affect cardiac function/rhythm with unclamping.

Answer 16

Trash foot from atheroembolization of fibrin, platelets or dislodged atherosclerotic debris after unclamping that blocked the small pedal or digital ateries. You can't really help this guy because small pedal or digital vessals are inaccessible to embolectomy catheters. If he has patent tibial vessels and palpable pedal pulses significant healing commonly occurs. You can try to help with heparinization or antiplatelet therapy, but thrombolytic therapy is contraindicated in the post-surgical period.

Answer 17

MI, arrhythmia or heart failure occur perioperatively in 10% of patients. Cardiac mortality is 2-3%

Answer 18

Labs to check cardiac, pulmonary and renal status. Carotid duplex u/s and cardiac stress test +/- catheterization because 70% of perioperative and late fatalities are due to cardiac events.

Answer 19

Coronary angiography = Mod to severe angina, CHF w/exertion, LVEF \< 20% (\< 30% is good predictor of CHF, but not MI). Straight to surgery = asymptomatic and active lifestyle, stable angina w/vigorous lifestyle, age \> 80. DT scan = hx of MI, moderate angina, mild angina w/sedentary lifestyle.

Answer 20

Dipyridamole inhibits adenosine uptake into the heart and pharmacologically stresses the myocardium. Thallium is a tagged radionucleotide that shows areas of poor perfusion when the heart is stressed by dipyridamole. It has a good negative predictive value (96-99%) but poor positive predictive value (1-20%). If positive, next test should be a coronary angio.

Answer 21

At least 3 months

Answer 22

Risk for perioperative cardiac morbidity: Age \> 70, DM, Angina, Ventricular arrhythmia requiring tx, Q waves on pre-op ECG and DTS redistribution. 0 risk factors = 3% risk of MI. 1-2 risk factors = 15% risk of MI and patients need DTS +/- cardiac cath. \> 3 risk factors = 50% risk of MI, and patients need coronary angio.

Answer 23

Iliofemoral and popliteal. Note that 50% of patients with popliteal aneurisms have AAA and 50-75% of popliteal aneurisms are bilateral.

Answer 24

5.5 cm or larger in greatest diameter w/ life expectancy \> 2 years. 4-5cm is debatable beause they grow at an average rate of 4mm/year.

Answer 25

Major fluid shifts w/mobilization of 3rd spaced fluids on day 3. If fluids are not restricted or diuretics utilized the patients can develop pulmonary edema. Pts should also be monitored for arrhythmias from electrolyte abnormalities and MI from aortic clamping/unclamping. Incidence of erectile dysfunction is high after this procedure due to dissection of hypogastric circulation or autonomic nerves near the IMA...in this case the patient should see a urologist.

Answer 26

50% die before reaching a hospital, 80% die perioperatively. If the patient survives post-op complications inclued acute renal failure, MI and multiorgan system failure from hypovolemic shock.

Answer 27

\< 5cm = 4% yearly, 20% 5 years. 5-7 cm = 7% yearly, 33% 5 years. \> 7cm = 19% yearly, 95% 5 years.

Answer 28

Get them straight to the OR to clamp that aorta ASAP then fluid resuscitate during repair. Increased volume/BP can convert a contained rupture to a free intraperitoneal rupture and result in rapid death.

Answer 29

The rectosigmoid segment is at risk for ischemia because of IMA interruption from the aneurism + compromised collateral flow from the SMA and hypogagstric arteries.

Answer 30

Sigmoidoscopy shows edematous, hemorrhagic or necrotic mucosa. Tx w/bowel rest, hydration, blood products if needed, GI decompression, abx, repeat endoscopy and colectomy for portions w/full-thickness involvement (mortality rate of 50%).

Answer 31

Vascular graft infection can arise months to years post-op and is typically due to normal skin flora S. epidermidis (evades immune system w/glycocalyx slime) or S. aureus at the implantation site. Dx with CT. Tx with graft removal, infected tissue debridement, revascularization by extra-anatomic bypass and long-term abx.

Answer 32

Aortoenteric fistula. Erosion of the graft into the 3rd or 4th part of the duodenum. Dx w/CT or angio, even if bleeding has resolved because pts typically present with a small sentinal bleed followed by massive bleed 1-2 days later. Tx w/graft removal, GI tract repair and extra-anatomic bypass. Note that mortality/limb loss approaches 50% with this.

Answer 33

Presents as post-prandial abdominal pain, usually w/o heme in stool. Dx w/arteriogram and tx w/revascularization or stenting.

Answer 34

Transesophageal echocardiography, CT, angiogram or MRI, depending on the urgency of the situation.

Answer 35

Type I = false lumen involves ascending aorta, arch and descending aorta. Type II = ascending only. Type III = descending only, distal to subclavian. Types I and II are stanford A dissections and type III is a stanford B dissection.

Answer 36

Managment is typically medical with control of hypertension using beta blockers. The exception to this rule are dissections that involve the ascending aorta, these need to be repaired surgically (types I and II, type A).

Answer 37

H&P is only accurate 50% in patients with DVT because 50% of patients have occult (silent) DVT. The most reliable clinical sign of DVT is new onset unilateral leg swelling measured \> 3cm compared to the other leg. Homans' sign, a palpable cord and thigh/calf tenderness are non-specific.

Answer 38

Duplex u/s has a sensitivity and specificity \> 90%.

Answer 39

70-100 U/kg heparin IV bolus initially. Maintenance infusion 15-25 U/kg for 4-6 days. Maintain PTT at 1.5-2x normal, check PTT 6 hours after initial dose (heparin t1/2 = 90 min), q8 for 1st 24 hours, then qd thereafter. Bed rest for 1st 24-48 hours and continued duplex u/s as heparin has anti-inflammatory properties that reduce the pain associated w/DVT. After 5-7 days, the patient can be started on Warfarin (Coumadin) and kept on it for 4-6 months with an INR of 2-3 (1.3-1.5x normal PT).

Answer 40

Heparin: activates ATIII. Warfarin: inhibits vitamin K epoxide. Plavix: inhibits platelet activation at ADP receptor. Aspirin: inhibits TxA2 \> PGI2.

Answer 41

Hemorrhage and HIT due to anti-heparin abs binding to and activating platelets

Answer 42

Several days. Warfarin inhibits synthesis of clotting factors II, VII, IX and X along with protein C and protein S. Early on proteins C/S are inhibited more and induce a hypercoaguable state anywhere from 1-10 days and heparin will help prevent clots during this time.

Answer 43

Supportive stockings and ulcer care. Note that if the patient has arterial occlusive disease, the supportive stockings will be counterproductive due to arterial compression.

Answer 44

Recurrence and post-thrombotic syndrome. Post-thrombotic syndrome is due to venous valve insufficiency resulting in venous HTN, chronic edema, skin ulceration around ankles and claudication.

Answer 45

Elderly, previous PE/DVT, long surgery, pelvic/ortho surgery, surgery for cancer, procoagulant state (polycythemia vera), hyperviscous (multiple myeloma) and hx of MI, CHF or COPD.

Answer 46

Age \> 40, 2-3 hour surgery, abdominal/thoracic surgery, obesity and smoking.

Answer 47

Healthy, \< age 40, short surgery or bleeding disorder (chronic renal or liver failure)

Answer 48

Trendelenberg position (knees and feet higher than right atrium), early ambulation, low-dose heparin (5,000 IU q8-12hrs until patient is ambulatory, coag studies are not necessary) and SCDs.

Answer 49

Good H&P, ECG (to r/o MI), ABGs (most common finding is low PCO2 due to hyperventilation), CXR (r/o PTX, atelectasis and pneumonia). If these tests don't really show anything, you can do a CTPA, which is the gold standard for PE.

Answer 50

Radioactive xenon gas is inhaled and lungs are assessed for for ventilation on CXR. Radioactive technecium is injection and lungas are assessed for perfusion on CXR. Impaired regional alveolar ventilation results in vasconstriction and a perfusion deficit on the scan. If the ventilation scan is normal in an area with segmental perfusion deficit, the deficit is very likely to be due to mechanical obstruction (PE), rather than physiologic (90% specific).

Answer 51

Most return to baseline after 1 month, exceptions to this include the elderly and those with pre-existing cardiopulmonary disease.

Answer 52

Pre-existing lung disease like COPD, bronchitis and restrictive lung disease, especially if there is no prior CXR to compare against.

Answer 53

Saddle emboli. This is because they do not yet affect the smaller pulmary arteries and perfusion deficits will not be prominent. This is one reason why we use CTPA.

Answer 54

Heparin failure to prevent PE and complications with heparin

Answer 55

Acute interruption of venous outflow resulting in inflammation, cyanosis and pain in the affected limb that can progress to sensorimotor loss and venous gangrene.

Answer 56

Anticoagulation and limb elevation come 1st. Then proceed to confirming the diagnosis with duplex u/s, CT or contrast venography. Most conditions resolve with this treatment, venous thrombectomy is rarely indicated.