vascular Flashcards
mc cause of arterial stenosis and occlusion
atherosclerosis
mc sites of atherosclerotic plaques
coronary arteries, carotid bifurcation, proximal iliac arteries, and adductor canal region of distal superficial femoral arteries
difference between true and false aneurysms
true-includes dilation of all 3 layers of arterial wall;
false (pseudo)- not all 3 and secondary to trauma, infection, or disruption of an arterial bypass anastomosis
mc site of aneurysms
infrarenal aorta, iliac arteries, and popliteal arteries
most life threatening occurrence of an aneurysm
rupture
best screening test for aneurysm
US
imaging for AAA
confirmed by US then CT; +/- angiography
adv of retroperitoneal incision compared to midline abdominal incision for open surgery for AAA
ease of access to perirenal and suprarenal aorta as well as dec postop pulmonary dysfunction
operative approach for AAA
normal infrarenal aorta and distal arteries are dissected and isolated. After heparinization, the aorta is clamped and the aneurysm incised. A prosthetic graft is sewn in place and covered with the residual aneurysm sac
adv of endovascular repair of AAA
dec periop mortality, dec blod loss, shortened hospital stay, and more rapid return to normal activty
disadv of endovascular repair of AAA
need for reg f/u requiring annual abdominal us or ct, inc rate of secondary interventions to correct problems w fixation of aortic graft, leakage of blood into aortic aneurysm safe, and risk of renal dysfunction secondary to contrast agents
classic triad of AAA
back pain, hypotension, pulsatile abd mass
permissive hypotension
w rupture AAA, restrict volume resuscitation so systolic bp stays between 70-80 w monitoring of mental status and organ perfusion; it minimizes ongoing blood loss through aortic defect
immediate complications of aortic aneurysm repair
MI, renal failure, colonic ischemia, distal emboli, hemorrhage
long term complications of aortic aneurysm repair
aortic graft infx, aortoenteric fistula, and graft thrombosis
pt who experiences diarrhea postop after aortic aneurysm repair should undergo what and why
sigmoidoscopy to eval sigmoid and rectum; can be colonic ischemia from disruption of pelvic arterial collateral flow, ligation of IMA, or period hypotension
sudden upper GI bleeding (“herald bleed”) after AAA replacement w prosthetic grafts
aortoenteric fistula; best imaging is upper endoscopy
endoleak I after repair of aortic or iliac aneurysm
leak at either the proximal or distal attachment site. This is associated with a high rate of expansion and rupture, and should be repaired with either placement of an additional stent graft or replacement of the endovascular graft with an open repair
endoleak II after repair of aortic or iliac aneurysm
persistent flow into and out of the aneurysm sac from lumbar or inferior mesenteric arteries. Generally, type II endoleaks are not treated unless there is expansion of the aneurysm sac or symptoms.
endoleak III after repair of aortic or iliac aneurysm
occur from a modular disconnection between components of the stent graft or a tear in the fabric of the graft. They should be repaired when identified
endoleak IV after repair of aortic or iliac aneurysm
due to diffusion of blood and serum through the graft and generally will resolve once anticoagulation is reversed at the conclusion of the surgical procedure.
PAD is dictated by what
number and severity of occlusions, degree of collateralization, and pt’s tolerance to limitations in walking distance
between the ages of 45-65 what two arteries are more likely to become stenosed or occluded in PAD
aorta and iliac
PAD below the inguinal ligament is known as
femoropopliteal occlusive disease- usually asymp except w extensive exercise
mc site of PAD
distal superficial femoral artery (SFA) within the adductor (hunter’s) canal
PAD below popliteal trifurcation known as
tibial occlusive ds- common in pt w diabetes, end stage renal failure, and adv age
leading cause of development of symptoms of PAD
enlargement of an atherosclerotic plaque
after what % of stenosis can the artery no longer adapt its diameter leading to the dev of stenosis
40%
ischemia of the lower extremity can cause
intermittent claudication, ischemic rest pain, skin ulceration, and gangrene
claudication related to PAD and not meeting the metabolic demands to muscles during exercise result in
conversion to anaerobic metabolism and painful local metabolic acidosis
Leriche syndrome
impotence, lower ext claud, and muscle wasting of buttocks due to aortoiliac occlusion
occlusion of SFA causes claudication where
calf
what does ischemic rest pain indicate
more advanced peripheral ischemia
what is rest pain caused by and what is a temporary relief
caused by nerve ischemia of tissues that are most sensitive to hypoxia; relief by dangling legs over side of bed or walking
arterial ulceration location and presentation
toes/heel/dorsum of foot; painful; ischemic ulcers may have punched out appearance and a pale or necrotic base
location of venous ulcers
medial or lateral malleolus (“gaiter zone”)
dry vs wet gangrene
dry is mummification of digits of foot without assoc purulent drainage or cellulitis; wet is assoc w ongoing infx, malodorous w copious purulent drainage
s/sx of PAD on PE
loss of hair on distal aspect of leg, muscle atrophy, color changes in leg, and ulcers or gangrene; Buerger’s sign
Buerger’s sign
assoc w PAD; dependent rubor; foot dangled, pooling of oxygenated blood in the maximally dilated arteriolar bed distal to an arterial occlusion causes the foot to appear red; when elevated, hydrostatic pressure dec, pooled blood drains and foot becomes white
what should pts w extremity ischemia be examined w
continuous wave doppler us
normally a triphasic waveform is seen on Doppler, what is seen for proximal stenosis
biphasic waveform and as progresses will become wider and monophasic
ankle-brachial index (ABI)
comparison of the systolic blood pressure at the level of the ankle divided by the brachial arterial pressure; this ratio provides an assessment of the degree of lower extremity arterial occlusive disease, with the brachial arterial pressure used as a control
results of ABI
> 0.9 normal,