Transcript Document

Endovascular Repair of
AAA and TAA
A. Berezin, MD, Ph.D
2/14/2007
Endovascular Repair of AAA
Endovascular Repair of AAA
Endovascular Repair of AAA
Current estimates are that more than 20000 EVAR procedures take
place each yeas in the USA, which represents ~36% of all AAA
repair.
The estimate is that >12% of all procedures in Europe are with
EVAR, and expected annual growth is ~15% at this time.
The endovascular repair of AAA and TAA has became a viable
alternative to open repair and is often the approach of choice for
high risk patients because of its:
minimal incisions,
shorter operating time
reduced blood loss.
Endovascular Repair of AAA
A ruptured AAA has a mortality rate
approaching 90%.
When an AAA is repair electively, the mortality
drops to less than 5%.
AAA affects 4% 7% of adult over the age of 65
years, with a far greater prevalence in male than
in female, this problem will encounter more
frequently as population ages.
Indications for AAA treatment
Patients with symptomatic aneurysms should
be offer repair, after careful consideration of
comorbidities, even if the aneurysm is not of
usual elective operation size.
Patients with the aneurysm increases in size by
1 cm per year.
Indications for AAA treatment
Most asymptomatic AAA’s are discovered by accident
often on imaging examination for other complains.
For the patients with asymptomatic AAA’s there is
guidelines to help plan further surveillance or operative
repair.
The size of the AAA is one factor, and the operative
approach is another.
In general, the clinical recommendation remains to offer
treatment for AAA between 5 and 5.5 cm, depending on
the results of clinical trials.
Clinical and Anatomical Selection Factors
Patient selection has emerged as the most important factor related
to successful EVAR.
3D reconstruction CT scan or angiography with a calibrated catheter
necessary for assessment for EVAR eligibility.
Proximal neck: diameter, length, angel, presence or absence of
thrombosis
Distal lending zone: diameter and length
Iliac arteries: presence of aneurysm or occlusive disease
Access arteries: diameter, presense of occlusive disease
Up to 37% of all patients may NOT be suitable candidate for EVAR of
their infrarenal AAA.
Evaluation for EVAR
Contraindications for EVAR
Short of proximal neck
Thrombus present in proximal landing zone
Conical proximal neck
Greater than 120º angulations of the proximal
neck
Critical inferior mesenteric artery
Significant iliac occlusion
Torture of iliac vessels
EVAR AAA Repair
Indication for EVAR AAA repair
Open repair is advocated for younger, lower-risk patients.
Open surgical repair of AAA has proven long-term durability.
EVAR is preferred for older, high risk patients.
EVAR has shown a reduction in 30-day mortality relative to that
achieved with open repair ( 1.2% versus 4.6% )
EVAR follow up is now 15 years.
Further study is required to determine whether there is a long-term
survival advantage.
Risk stratification determines survival in general and shows that both
open surgery and EVAR decrease the risk of death from AAA rupture
EVAR complications
Deployment related
Implant related
Failed deployment
Bleeding
Hematoma
Lymphocel
Infection
Embolization
Perforation
Arterial rupture
Dissection
Endoleaks
Limb occlusion/stent-graft kink
Sac enlargement/proximal neck
dilatation
Stent migration
AAA rupture
Infection
Buttock/leg claudication
Device related
Structural failure
EVAR complications
Systemic
Cardiac
Pulmonary
Renal insufficiency, contrast-induced neuropathy
Deep vein trombosis
Pulmonary embolism
Coagulopathy
Bowel ischemia
Spinal cord ischemia
EVAR complications
Endoleak is the most common complications, greater
than 20% - 30% in some studies.
An endoleak is define as persistent blood flow outside the
wall of the stent into the aneurysmal sac.
The endoleak exposes the weak aneurysm wall to
continues flow that may lead to rupture.
Any increase in the aneurysm sac warrants immediate
repair.
Classification of Endoleaks
I: Attachment site leaks
A.
B.
C.
Proximal end of endograft
Distal end of endograft
Iliac occluder ( plug )
II. Branch leaks ( without attachment side connection )
Simple or to-and-fro (from only 1 patient branch)
B.
Complex or flow-through ( with 2 or more patient branches).
III. Graft defect
A.
Junction leak or modulator disconnect
B.
Fabric disruption ( midgraft hole )
IV. Graft wall ( fabric ) porosity ( <30 days after graft placement )
A.
Intraoperative management,
M.M.Mondecai,2004
The procedure is less invasive.
Requires minimal anesthesia.
Less likely to induce homodynamic stress.
May still be associated with risks and
complications of any aortic surgery such as
massive sudden blood loss because of aortic
rupture.
Monitoring during EVAR of AAA
Appropriate catheters for homodynamic monitoring
Large-bore intravenous catheter.
Arterial catheter for continuous BP monitoring and to
collect samples for ABG, Hb, clotting time.
CVP line should be consider to provide central
vasopressors delivery and to maintain adequate
intravascular volume.
PA catheter or TEE can provide more accurate
assessment of cardiac function and intravascular volume
in patients with poor LV function or renal failure.
A Foley catheter is an additional measure of volume
status.
General Anesthesia, M.M.Mondecai,2004
GA typically consist of a balance technique with low-dose
inhalation agent and opioids.
Neuromuscular blockers are typically not necessary.
The case can be perform with laryngeal mask.
GA provides:
maintain of potency of airway
allows for homodynamic manipulation
accommodate for variation in duration of operation
reduce the possibility of patient movement
allows for control of respiration during fluoroscopy
General Anesthesia, M.M.Mondecai,2004
Placement intravascular lines or monitors is more easier.
Supine position tolerates better during long operation.
GA is:
associated with more hypotensive episodes
increased fluid requirement
increased use of inotropic support compare to RA
Regional Anesthesia, M.M.Mondecai,2004
Spinal, epidural, and combined spinal-epidural techniques
have been used.
T 10 sensory level is needed for iliac arteries exposure
provides fever homodynamic side effect.
Advantages of EA:
ability to titrate
achieve the appropriate sensory level
accommodate variation in duration of the procedure
minimize hemodynamic changes
shorter postoperative hospital stay
Regional Anesthesia, M.M.Mondecai,2004
Potential disadvantages with RA:
difficulties in patient comfort while placing intravascular
lines
patient tolerance for supine position on the OR table
need to convert to GA if procedure is converted to an
open repair
low risk of spinal or epidural hematoma while receiving
intrapoperative Heparin
Local anesthesia, M.M.Mondecai,2004
Local anesthesia well tolerated for transfemoral
approach:
Decrease fluid requirement
Decrease operating time
Decrease of innotropic agent
Decrease of hospital stay
Patient commonly feels pain during dilatation which
resolves with deflation of balloon.
Persistent pain after deflation of the balloon may indicate
arterial rupture with extravasation and should be
investigated.
PVB vs GA for EVAR of AAA, J.Falkensammer et al, 2006
(Jacksonville, FL)
10 pt with AAA repair with PVB with propofol
sedation ( 1 case conversion to GA due to block
failure) vs 15 pt. with GA
PVB (paravertebral blockade) :
less hypotension
less blood pressure liability
less postoperative PONY
PVB can be perform safely in pt. with significant
comorbidities
RA or LA techniques, M.M.Mondecai,2004
With RA or LA preparations must be made for conversion
to GA :
acute aortic rupture with hypotension ( hypotension may
include an allergic reaction to contrast dye and a side
effect of adenosine)
in the event of open procedure
if further access to the ileac arteries is needed
if patient is unable to tolerate supine position
innotropic and vasodilatating agent should be prepared
for the treatment of homodynamic instability
Proximal Graft Deployment, R.A.Kaplan et al,
Induced hypotension during device deployment has been
used successfully to assist in proximal placement and
may reduce the magnitude of migration:
pharmacological induction of sinoatrial and
atrioventricular nodal inhibition with high dose of
Adenosine
induced ventricular fibrillation (by applying an
alternating current to the endocardial surface through a
temporary transvenous ventricular pacing lead)
using Nitroglycerin or Sodium Nitroprusside
Postoperative care, M.M.Mondecai,2004
Recovery after uncomplicated EVAR does not routinely
require the use of ICU.
Analgesic requirement are minimal and can managed
with small boluses of opioids or NSAID.
Postinflamation syndrome related to a systemic
inflammatory response to graft material can occur,
manifesting with fever, leukocytosis, and increase Creactive protein concentration.
Hyperepyxia can be associated with tachycardia.
The average length of stay in the hospital is minimal.
EUROSTAR DATA, 2006
Influence of anesthesia on outcome after endovascular
AAA repair.
From 7/1997 to 8/2004, 5557 pt. underwent EVAR repair
in 164 centers were enrolled in the EUROSTAR registry.
General anesthesia (GA-G) - 3848 pt. (69%)
Regional anesthesia (RA-G) - 1399 pt. (25%)
Local anesthesia
(LA-G) - 310 pt. ( 6%)
Multivariable logistic regression analysis was performed
on early complications.
EUROSTAR DATA , 2006
LA-G, (6%)
RA-G,( 25%) GA-G, (69%)
Amount of patient
310
1399
3848
Duration of operation (min)
115 ± 42
127 ± 53
Admission to ICU
2%
8.3%,
16.2%
Hospital stay (day)
3.7 ± 3.1
5.1 ±7.5
6.2 ± 8.5
Systemic complications
6.6%
9.5%
133 ± 59
13%
EUROSTAR DATA, 2006
EUROSTAR data indicate that patients appeared to
benefit when a locoregional anesthetic technique was
used in EVAR.
Locoregional technique should be used more often to
enhance the preoperative advantage of EVAR in the
treating AAA.
Ultimately, a prospective randomize study is necessary to
clarify the question of which method of anesthesia is
suitable.
EVAR vs. open ruptured AAA repair, J.J. Visser, et
al 2006, Netherlands, MGH
EVAR vs. open ruptured AAA repair, J.J. Visser, et al 2006,
Netherlands, MGH
EVAR
Open repair
Unstable pt ( # )
26
29
30 day mortality
8 (31%)
9 (31%)
Systemic complications
8 (31%)
9 (31%)
Secondary intervention
5 (19%)
9 (31%)
Complications 1 year follow-up
1 (5%)
4 (16%)
EVAR vs. open ruptured AAA repair, J,J, Visser, 2006
Mortality and complications rates after EVAR may be
similar compared with those after open surgery in
patients treated for ruptured infrarenal AAA.
If emergency EVAR associated with higher secondary
intervention in AAA repair
B.I. Orenan et al, 2006, Netherlands
Rupture 34 pt Acute not rupt. 22 pt
Mortality at 30 days
Survival 1 year
Survival 2 year
18%
68 ± 9
62 ± 9
Survival 3 year
Secondary intervention
15%
Elective 322 pt
5%
1%
91 ± 6
85 ± 8
95 ± 1
90 ± 2
76 ± 11
86 ± 2
18%
12%
Is emergency EVAR associated with higher secondary
intervention in AAA repair ( B.I. Orenan et al, 2006)
To our surprise, emergency endovascular AAA
repair did not present with higher secondary
intervention rate at mid-term follow- up ( 38 ±
26 month).
Long-term outcome after EVAR AAA: The First
Decade, Brewster D.C et al, 2006, MGH
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873 pt underwent EVAR since 1/1994 to 12/2005
Mean follow up was 27 month
39% of pt had 2 or more major comorbidities
19% of pt. would be categorized as unfit for open repair
Device deployment was successful in 99.3%
30 day mortality was 1.8%
Freedom from AAA rupture was 97.6% at 5 years and 94% at 9 years
Significant risk factor for late AAA rupture included female gender and
device related endoleak
Aneurysm related death was avoided in 96%
87 (10%) pt. required reintervention, with 92% being catheter-based and a
success rate of 84%
Predictor for reintervention: first generation device and late onset endoleak
Long-term outcome after EVAR AAA: The First
Decade, Brewster D.C et al, 2006, MGH
Current generation stent graft correlated with significant improve
outcome.
Cumulative freedom from conversion to open repair was 93%
at 5 through 9 years.
Cumulative survival was 52% at 5 years.
EVAR using contemporary devices is a save, effective, and durable
method to prevent AAA rupture and aneurysm related death.
Assuming suitable AAA anatomy, these data justify a broad
application of EVAR across a wide spectrum of patients.
2 year Outcomes after Conventional of EVAR of
AAA
DREAM Trial Group, 2005
Randomized trial, multicenter comparing open repair with EVAR in 26
centers in Netherlands and 4 centers in Belgium.
Open repair
2 y survival rate
Aneurysm related death
Survival free of complications
EVAR
178 pt
173 pt
89.6
5.7
65.9
89.7
2.1
65.6
The perioperative survival advantage with EVAR repair as compare
with open repair is not sustained after the 1-st postoperative year.
Cost EVAR repair,
Abularrage CJ, et al. 2005
Open AAA (30pt)
“fast-track”
Length of surgery (min)
Volume of blood transfusion (un.)
Colloid transfusion (cc)
Crystalloid (cc)
Resume regular diet
EVAR (28pt)
216 ± 7.4
158 ± 6.8
1.8 ± .29
0.32 ± .24
565 ± 89
32 ± 22
4625 ± 252
2627 ± 170
1.8 ± .11
0.21 ± .08
Cost EVAR repair,
Abularrage CJ, et al. 2005
0.87 ± .01
0.50 ± .10
Floor stay ( day)
2.6 ± .21
2.1 ± .23
Total length of stay
(day)
Hospital cost ( $$ )
3.4 ± .18
2.8 ± .32
10.205 ± 736
20,640 ± 1206
ICU stay (day)
Hospital earning ( $$ )
6,141 ± 1280
107 ± 1940
Endovascular TAA repair
The first thoracic stent graft was deployed for TAA exclusion in 1992
Cumulative clinical experience is estimated 5000 implants worldwide
has yielded short- to mid-term data that demonstrated promising
results.
3 clinical trials are approval by FDA:
TAG (W.L. Gore and Associates, Inc),
Talent (Medtronic, Inc),
TX2 (Cook, Inc).
The endoprosthesis are composed of a metal skeleton (nitinol,
stainless steel, Elgiloy) covered with fabric ( polyester or
polytetrafluoroethylene PTFE).
Graft can be deployed by a self-expanding mechanism or balloon
expansion.
TAA repair
With an incidence of 6 to 10 per 100 000 person-years TAA’a less
common than AAA but remain life-threatening.
With an associated mortality rate of 94%, TAA rupture is usually a
fatal event.
The 5 years survival rate of unoperated TAA patients approximates
13%, whereas 70% to 79% of those who undergo elective surgical
intervention are alive at 5 years.
The risk of rupture mandates consideration for surgical treatment in
all patient who are suitable for operation.
Complications TAA repair
Mortality for TAA surgical repair ranges from 5% to 20% in elective
cases and to 50% in emergent situation.
Major complications associated with surgical TAA repair include:
Renal and pulmonary failure
Visceral and cardiac ischemia, stroke
Paraplegia
Paraplegia occurring in 5% to 20% of cases versus <1% for AAA.
For these reasons, a significant population of TAA patients are not
candidate for open repair and have been without a treatment
options until recently.
Endovascular TAA repair
Development of stent grafting in the TA has progress more slowly
1. The hemodynamic forces of the TA are significantly more
aggressive and place greater mechanical demand of thoracic
endografts. The potential for devise migration, kinking, and late
structural failure are important concerns.
2 .Greater flexibility is required of thoracic devices to conform to
the natural curvature and to the lesions with tortuous morphology.
3. Because larger devices are necessary arterial access is more
problematic.
4. TAA can often extend beyond the boundaries of the descending
TA and involve more proximal or distal aorta the desired.
Anatomical Requirements for Repair of TAA
A proximal neck at least 15 to 25 mm from the origin of the
left subclavian artery.
A distal neck at least 15 to 25 mm proximal to origin of the
celiac artery.
Adequate vascular access: absence of severe tortuosity,
calcification, or atherosclerotic plaque burden involving
the aortic or pelvic vasculature.
The transverse diameter of the proximal and distal neck
should be within the range that available devices can
appropriately accommodate.
EVAR TAA Repair
Indications for Endovascular Repair
Patient for TAA repair considers their overall risk profile:
evidence of rapid enlargement of aneurysm,
diameter > 6cm,
presence of symptoms
Endovascular stent grafting is currently reserved for high-surgical-risk
and nonoperative patients who have suitable anatomic features.
High resolution 3D rendering of the aorta, catheter based
angiography remains the “gold standard” which helps to select the
appropriate device diameter and length.
Determination of aneurysm location in relation to the left subclavian
and celiac axis is up most importance.
Requirements for EVAR Repair
Vascular access route must be of sufficient size.
Small-diameter of femoral arteries, tortuous, and excessive calcified
of iliac arteries requiring more proximal retroperitoneal exposure.
Severe stenosis and tortuosity of abdominal or thoracic aorta distal
to the target are contraindication for endovascular repair.
Treatment failure can occur.
Follow up surveillance with serial CT scan at 1, 6 and 12 months is
recommend to monitor changes in aneurysm morphology, identify
device failure and detect endoleaks.
Endovascular Repair of TAA
Successful device deployment is achieved in 85% to
100% of cases.
Preoperative mortality ranges from 0% to 14%, falling
within or below elective surgery mortality rates of 5% to
20%.
Outcomes have improved over time:
with accumulative technical experience
use of commercially manufactured devices
improved patient selection criteria
Endovascular Repair of TAA
Collective experiences of the EUROSTAR and United Kingdom
Thoracic Endograft registries:
the largest series to date ( n=249)
demonstrate successful rate deployment in 87% of cases
30-days mortality of 5% for elective cases
paraplegia and endoleak rates of 4%
FDA phase II trial data from exclusive deployment of the Gore TAG
endograft in 142 TAA patients reveal similar resuils:
technical success in 98%
30-days mortality of 1.5%
endoleak in 8.8%
Complications
Endoleak is less than reported for AAA endograft repair.
More commonly at the proximal or distal attachment sides ( type I)
represent direct communications between the aneurysm sac and
aortic blood flow.
Treatment options include:
transcatheter coil
glue embolization
balloon angioplasty
placement of endovascular graft extention
open repair
Paraplegia
Incidence of paraplegia is lower due to:
avoidance of aortic cross-clamping
avoidance prolonged iatrogenic hypotension
Occurrence of paraplegia is associated with:
concomitant or prior surgical AAA repair
increased exclusion length because of the
absence of lumbar and hypogastric collateral
circulation.
Strategies to Manage Paraplegia Risk after
EVAR Repair of TAA, AT Cheung,2005
75 pt ( male=49, female=26, age =75+/-7.4 years)
Lumbar CSF drainage ( n=23) and Somatosensory EP monitoring ( n=15)
were performed selectively in pt. with significant aneurysm extent or with
previous AAA repair (n=17).
Spinal cord ischemia occurred in 5 pt. ( 6.6% ):
2 had SSEP loss after stent deployment
4 developed delayed-onset paraplegia
2 had full recovery in response to art. pressure augmentation alone
2 had full recovery
1 had near-complete recovery in response to art. pressure augmentation and
CSF drainage
The incidence of permanent paraplegia or paraparesis was 2.7% (2 0f 75)
Risks Spinal Cord Ischemia
(Chung et al, 2005)
Previous AAA repair.
Hypotension associated with an occult retroperitoneal
bleeding.
Severe atherosclerosis of the Thoracic aorta.
Injury to the external iliac artery.
Extend of the descending Thoracic aorta covered by
graft.
Strategies to Manage Paraplegia Risk after
EVAR Repair of TAA, AT Cheung,2005
Early detection and intervention to augment spinal cord perfusion
pressure was effective for decreasing the magnitude of injury or
preventing permanent paraplegia from spinal cord ischemia after
EVAR of descending TAA.
Routine use of motor and somatosensory evoked potential
monitoring,
serial neurological assessment,
arterial pressure augmentation,
CSF drainage
may benefit patients at risk for paraplegia.
Stent graft vs open repair TAA, D.H.Stone et. Al, 2006, MGH
Type of repair
Stent-graft
Open
Patients number
105 pt.
93.pt.
Perioperative. mortality
7.6%
15.1%
Survival 48 month
54%
64%
Spinal cord injury
6.7%
8.6%
Reintervention
10.5%
9.7%
Stroke
9.5%
Stent graft vs open repair TAA, D.H.Stone et. Al, 2006,
MGH
Operative mortality was halved with Sten-graft,
with similar late survival for both groups.
Reinterventions were required at a nearly
identical rate for open and Stent-graft.
Spinal cord injury were similar in both groups.
Endovascular Repair of AAA and TAA
The introduction of EVAR of aortic aneurysm
has presented a unique treatment option to
approximately half of the patients presenting for
AAA repair.
The immediate benefits of reducing early
morbidity, blood loss, length of stay, and
recovery have been proven.
The long –term success of the EVAR is of
concern because of the need for lifelong
surveillance, secondary intervention, and
continued risk of the aneurysmal rupture .
Endovascular Repair of AAA and TAA
As the technology of this surgical technique
continues to develop, there is hope that material
and structural designs will help resolve some of
these issues.
Indications for endovascular stent graft
replacement now extend well beyond elective
AAA repair to include repair of ruptured AAA in
patients with contained bleeding, TAA
aneurysm, and aortic injuries caused by trauma.