Angela Diamond, MD, FACS, RVT.. Endovascular Repair of Aneurysms Abdominal Aorta Generally a disease...
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Endovascular Repair of Aneurysms Angela Diamond, MD, FACS, RVT.
Angela Diamond, MD, FACS, RVT.. Endovascular Repair of Aneurysms Abdominal Aorta Generally a disease of older males: Annual incidence of less than 1 in
Endovascular Repair of Aneurysms Abdominal Aorta Generally a
disease of older males: Annual incidence of less than 1 in 1000
people younger than 60 years old Peaks at approximately 7 in 1000
people in their mid-60s 5 to 6 times more common in men than
women.
Slide 3
Endovascular Repair of Aneurysms Abdominal Aorta Risk factors
include: Male gender Positive family history Older age Smoking
Coronary Artery Disease Peripheral Vascular Disease White race
Hypercholesterolemia.
Slide 4
Endovascular Repair of Aneurysms Abdominal Aorta Definition: An
aneurysm is defined as a widening or dilatation of a vessel. The
infrarenal diameter should be 1.5 times the expected diameter.
Normal diameter varies with age, sex and body weight. Therefore, no
definite diameter; however, conventionally diagnosed when the
infrarenal aorta has a transverse diameter of at least 30 mm.
Slide 5
Endovascular Repair of Aneurysms Abdominal Aorta The dilatation
affects all 3 layers of the aorta and is usually fusiform, i.e.
affecting the whole circumference. Pathogenesis is poorly
understood, the development is clearly associated with alterations
in the connective tissue in the aortic wall. The aortic wall
contains vascular smooth muscle cells as well as matrix proteins -
elastin and collagen.
Slide 6
Endovascular Repair of Aneurysms Abdominal Aorta Histological
features of an aneurysm wall: Fragmentation of elastic fibers in
the media Dilatation of the medial wall Then the adventia, which is
primarily made up of collagen, becomes responsible for the strength
of the aorta Collagen degradation is the ultimate cause of
rupture.
Slide 7
Endovascular Repair of Aneurysms Abdominal Aorta The
alterations in collagen and elastin in the aortic wall is dependent
on production of proteases by medial smooth muscle cells,
adventitial fibroblasts and the cells of the lymphomonocytic
infiltrate. Matrix Metalloproteinases (MMPs) Tissue Inhibitors of
Matrix Metalloproteinases (TIMPs).
Slide 8
Endovascular Repair of Aneurysms Abdominal Aorta Abdominal
aortic aneurysms (AAA) may be asymptomatic for years; however, 30%
will go on to rupture, if left untreated. Majority of patients with
ruptured aneurysms die before making it to the hospital or
emergency room. Those who make it to surgery have a high morbidity
and mortality and only 10%-25% will ultimately survive until
discharge.
Slide 9
Endovascular Repair of Aneurysms Abdominal Aorta Risk of
rupture is related to the size of the aneurysm. Multiple studies
have agreed that the risk of rupture increases to a point that
elective repair is warranted when the diameter reaches 5.0 to 5.5
cm Controversy exists in the management of small aneurysms.
Slide 10
Endovascular Repair of Aneurysms Abdominal Aorta Diameter of
the AAA is not the only isolated factor in risk of rupture; small
aneurysms do rupture and larger ones remain stable for long periods
of time. Studies have shown that a larger initial diameter, COPD,
and hypertension have all been independent predictors of rupture.
Female gender (women having a 3-fold higher risk of rupture than
men), familial AAAs and smoking have also been implicated.
Slide 11
Endovascular Repair of Aneurysms Abdominal Aorta Current
thinking is rupture depends on diameter: AAA < 4 cm 0% per year,
rupture AAA 4 to 5 cm 0.5 to 5.0 % per year, rupture AAA 5 to 6 cm
3 to 15 % per year, rupture AAA 6 to 7 cm 10 to 20 % per year,
rupture AAA 7 to 8 cm 20 to 40 % per year, rupture.
Slide 12
Endovascular Repair of Aneurysms Abdominal Aorta History and
Physical Exam Hypertension, COPD, coronary artery disease, smoking,
family history of AAA. Positive physical examination of the
supra-umbilical region with bimanual palpation depends on the size
of the AAA: 61% for 3.0 to 3.9 cm 69% for 4.0 to 4.9 cm 82% for 5
cm or greater.
Slide 13
Endovascular Repair of Aneurysms Abdominal Aorta Noninvasive
Imaging: Abdominal x-rays Ultrasonography Computed Tomography
Angiography Magnetic Resonance Angiography Conventional
Angiography. US Preventive Services Task Force is now recommending
screening for all men ages 65 to 75, who ever smoked, for AAA, via
an abdominal aortic ultrasound.
Slide 14
Endovascular Repair of Aneurysms Abdominal Aorta Medical
Treatment Beta blockers, specifically propranolol Indomethacin
Angiotensin II blockers Nonsteroidal anti-inflammatory drugs
Tetracyclines HMG-CoA reductase inhibitors (statins)
Angiotensin-converting enzyme inhibitors.
Slide 15
Endovascular Repair of Aneurysms Abdominal Aorta Indications
for Intervention: Rupture > 5.5 cm Rapid expansion in a short
period of time, > 0.7cm in 6 months Symptomatic aneurysms:
patients with pain and tenderness over their aneurysm Complications
associated with aortic aneurysms: Distal embolization Thrombosis
Fistulization Local compression of adjacent organs.
Slide 16
Endovascular Repair of Aneurysm Abdominal Aorta Open Repair:
1923, Rudolph Matas performed the first successful aortic ligation
to treat aortic aneurysm 1930, Blakemore and King tried to induce
thrombosis of the aneurysm sac by passing a current through wires
that were placed into the aneurysm sac 1940s, cellophane was used
in humans to wrap the aorta to induce periarterial fibrosis, to
prevent rupture 1951, Dubost performed the first successful
aneurysm excision and repair with the use of an arterial homograft
to replace an aortic aneurysm 1954, Debakey performed an AAA repair
using Dacron. In the 1950s, aneurysms were excised prior to
replacing the aorta with a graft. 1960s, Oscar Creech popularized
the open endoaneurysmorrhaphy that we know it today, leaving the
back wall of the aneurysm intact and oversewing the lumbar
vessels.
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Endovascular Repair of Aneurysms Abdominal Aorta Endovascular
Repair (EVAR) for an AAA was first described by Parodi et al in
1991. This technique modeled after the work by Dotter et al was
initially designed for patients too sick to undergo conventional
open aortic repair. The endograft is a vascular prosthetic graft
attached to a stent and is delivered to the aorta via a
transfemoral route. Under fluoroscopic guidance, the device is
placed beneath the renal arteries and deployed- essentially
relining the aorta. Once the endograft is in place the blood
travels through the device and excludes the aneurysm sac,
preventing rupture. The initial endografts were physician
made.
Slide 19
Endovascular Repair of Aneurysms Abdominal Aorta 3 areas of
review are needed before considering the patient for an EVAR:
Proximal Neck 1.5 cm in length, up to 32 mm in diameter Distal
Landing Zone Ectasia and/or aneurysmal Access Vessels Calcium and
tortuosity.
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Slide 22
Endovascular Repair of Aneurysms Abdominal Aorta Clinical Trial
of EVAR Endovascular Aneurysm Repair 1 Trial (EVAR-1) Dutch
Randomized Endovascular Aneurysm Management Trial (DREAM) Open
Versus Endovascular Repair Trial (OPEN) United Kingdom EVAR Trial
Investigators.
Slide 23
Endovascular Repair of Aneurysms Abdominal Aorta Complications:
Endoleaks I: Inadequate seal of proximal or distal end. II: Flow
from patent lumbar, middle sacral or inferior mesenteric artery.
III: Fabric disruption or tear. Module disconnection. IV: Flow from
fabric porosity.
Slide 24
Endovascular Repair of Aneurysms Thoracic Aorta The thoracic
aorta can be divided into 3 segments: The ascending aorta (from the
heart to the innominate artery) The aortic arch (from the
innominate artery to the left subclavian artery) The descending
aorta (from the left subclavian artery to the level of the
diaphragm) Beyond is the visceral aortic segment, wherein the renal
and the visceral vessels arise.
Slide 25
Endovascular Repair of Aneurysms Thoracic Aorta Aneurysms of
the descending thoracic aorta are mostly degenerative in nature and
indistinguishable from AAA. 20-30% of aortic aneurysm patients have
a first order relative with the disease. Continues to be a debate
over whether aneurysmal degeneration is a sequela of
atherosclerosis or a primary connective tissue weakness, recent
studies suggest overlap.
Slide 26
Endovascular Repair of Aneurysms Thoracic Aorta The second most
common etiology of descending thoracic aortic aneurysms is as the
sequela of chronic aortic dissection. Of patients experiencing
acute aortic dissection, 25% to 40% will develop chronic aneurysmal
dilatation of the outer wall of the false lumen, which renders them
susceptible to late aneurysm rupture and death. Giant cell
arteritis, Marfans syndrome.
Slide 27
Endovascular Repair of Aneurysms Thoracic Aorta Expected
natural history is progressive enlargement and eventual rupture,
regardless of etiology or location. Women make up half of thoracic
aneurysm patients as opposed to 10%-20% of those with AAA. Mean
rate of growth for all thoracic aneurysms is 0.1 cm per year.
Slide 28
Endovascular Repair of Aneurysms Thoracic Aorta Natural history
observations have led to the acceptance of 6 cm as the size
threshold for recommendation of surgical intervention for
degenerative descending thoracic aneurysms. Or growth rates of
>10 mm per year. Increasing expansion rate is used an indicator
of heightened rupture risk as is the presence of aortic tenderness,
and, in some cases, consideration is given to earlier
operation.
Slide 29
Endovascular Repair of Aneurysms Thoracic Aorta Clinical
presentation: Chest and/or back pain New onset of hoarseness
Chronic cough Hemoptysis Dyspnea Dysphagia lusoria Distal
embolization. Medical treatment consists of beta blockers to keep
the systolic pressure at the low normal range of 105 to 120 mm Hg,
and this often requires additional medications to maintain.
Slide 30
Endovascular Repair of Aneurysms Thoracic Aorta Endoluminal
treatment of isolated thoracic aortic aneurysms with stent grafting
was introduced in 1994, by Dake et al. Several anatomic barriers to
thoracic stent grafting: Proximal and distal seal zones should be
at least 2 cm in length. Delivery systems for thoracic endografts
are larger than their abdominal counterparts, with the largest
devices requiring an iliac diameter of 9 mm.
Slide 31
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Endovascular Repair of Aneurysms Thoracic Aorta Results:
PIVITOL trial EUROSTAR United Kingdom Thoracic Endograft
registries.
Slide 34
Endovascular Repair of Aneurysms Popliteal Artery Aneurysm of
>2.5 cm If left untreated, patients do not present with rupture
but with acute limb ischemia due to occlusion of the aneurysm with
clot. Stent placement via common femoral artery Continue to need a
seal zone 2 cm above and below the aneurysm, not including the
tibial peroneal trunk. Plavix and aspirin for the lifetime of the
patient due to a small covered stent in a bendable part of the
extremity.
Slide 35
Endovascular Repair of Aneurysms Conclusion Infrarenal
abdominal, descending thoracic and popliteal artery aneurysms have
all been successfully stented with covered stents. We do more
vascular surgery stenting for aneurysms here at Harrison hospital
than any other hospital in Washington state except for the
University of Washington hospital system. An aneurysm that has not
been successfully stented endovascularly is a common femoral artery
aneurysm due to its branching into the superficial femoral and the
profunda arteries. Thank you very much for your time today!