Transcript Management of Acute Aortic Dissection Type A

Interhospital conference ครัง้ ที่ 29
Acute Aortic Syndrome
MANAGEMENT OF ACUTE AORTIC
DISSECTION TYPE A
นพ.ณัฐพล อารยวุฒกิ ลุ
หน่ วยศัลยกรรมหัวใจทรวงอกและหลอดเลือด
โรงพยาบาลศูนย์ลาปาง
 King George 2 of Great Britain died(october
25,1760)while training on the commode and was the
first well documented case of an aortic dissection.
Historical Note
 Recognized since 16 th century.
 Lannaec(French physician) introduced term
Dissection aneurysm in 1819.
Historical Note
 First successful outcome of modern treatment of aortic
dissection was attributed to Dr. DeBakey in his report,
1955 and later he devised a classification that is widely
used today as Debakey classification.
Historical Note
 Technological and technical improvements follow:
 Cardiopulmonary bypass circuit.
 Synthetic placements.
 Hypothermic circulatory arrest in 1960s to 1975(
Barnard , Schrire, Borst and Griepp with colleaques)
 Open distal anastomosis technique by Livesay in 1982.
 Bioglue has been approved by US FDA to strengthen
the disrupted layer.
Classifications
 De Bakey
 Type 1 = ascending aorta, aortic arch, descending
aorta
 Type 2 = ascending aorta only
 Type 3 = descending aorta distal to left subclavian
artery
 Type 3a= limit to descending thoracic aorta
 Type 3b= extend below diaphragm
 Stanford (most common)
 Type A = involves ascending aorta
 Type B = no ascending aorta, distal
Type of Aortic Dissection
 The proportion of patients with various types
depend on the nature of series reported
 Type one and two (or type A) comprised 35% of
cases (from Debakey series).
 From clinical and autopsy series, acute
dissections involved the ascending aorta was
found in 62% to 85% of cases.
Intramural Hematoma
Intramural hematoma involving the ascending aorta
Should be treated like an acute type A aortic dissection
Aortic IMH is considered a precursor to classic aortic dissection
T sai TT. Acute aortic syndromes. Circulation 2005
Natural history
 50% are dead within 48 hrs
 Long term survival in
untreated type A
dissection:
 More than 25% died in 24
hrs.
 More than 50% died in the
first week.
 More than 75% died in 1
month.
 More than 90% died in 1
year.
Mode of Death
 Most patients who die acutely succumb from
false channel rupture with hemopericardium,
hemomidiastinum or hemothorax.
 Death later can result from delayed rupture
or organ dysfunction secondary to arterial
occlusions.
Course after surviving acute
dissection
 False channel usually and gradually become
aneurysmal, and then ruptures months or
years after the acute episode.
 A new dissection or redissection may occur.
Presentation
 40% die immediately
 30% who present to hospital are first thought to
have another diagnosis
 Most common symptom:
 Severe, unrelenting chest pain
 Described as ripping or tearing/ sharp pain





Patients look agony ( nausea, vomiting, diaphoresis)
Symptoms of tamponade
AR murmur
Abnormal pulse exam
Abnormal neurologic exam
Exam
 Can be normal
 Hypertension ( normal or low does not
exclude dissection)
 If subclavian artery involved = asymmetri
pulses or BP ( > 20 mmHg difference between
arms)
 If proximal dissection
 Shock
 New murmur of AR/ HEART FAILURE
Initial diagnostic steps and
decisions
 EKG
 Normal in 1/3 ( in coronary involement)
 ST-T change
Initial diagnostic steps and
decisions
 TTE
 Useful screening tool in identifying type A
dissection
 Limited visualization to distal ascending,
transverse and descending
 Paramount in assessing cpx. AR/tamponade/EF
 TEE
 TEE with color flow imaging is considered as the
most useful and accurate diagnostic technique
Initial diagnostic steps and
decisions
 Coronary angiogram
 selective coronary angiogram to identify involvement of the
coronary arties is not indicated.(TEE, direct examination of
coronary arteries after the aorta was opened)
 Use of coronary angiogram to detect atherosclerotic disease in
patients who are to undergo surgical treatment of acute
dissection is arguable.
Aortic dissection diagnostic
studies
 Helical CT sense-93% spec-100%
 Most frequently used
 MRI sens-98% spec 98%
 Presence of artifact in nearly 60% of cases
 Echo TTE sense-59-85%, spec 63-96%
 Echo TEE sense-98%, spec 98%
 IVUS
 Particulary useful for delineating the proximal and distal extent
 Coronary angiography
 Controversial
What is the optimal treatment
General principles
 Acute aortic dissections involving the
ascending aorta are considered surgical
emergencies.
General principles
 In contrast, dissections confined to the
descending aorta are treated medically
unless there is/are complications.
Initial medical Therapy
 The primary objective is to normalize
pressure and to reduce the force of left
ventricular ejection (dP/dt).
Initial medical Therapy
 If beta-blockers alone do not control blood
pressure, vasodilators such as NTP ( the first
vasodilator of choice)
 Good pain control as morphine.
 Volume titration.
 Intubation early.
Hypotensive patients
 Cardiac tamponade
 Severe AR
 True-lumen obstruction
 Acute MI
 Contained rupture of the false lumen into
pleural space or mediastinum
 ### every scenarios mandate immediate
operative intervention####
Pericardiocentesis
 Associated with recurrent pericardial bleeding and associated
mortality
 Several articles from Asian literature suggest that it may be safe in
the setting of acute type A IMH
 Except for cases who cannot survive until
surgery, pericardiocentesis can be done by
withdrawing just enough fluid to restore
perfusion
Purpose of Surgical
Treatment
 To treat or prevent the common and lethal
complications such as
 Aortic rupture
 Stroke
 Visceral ischemia
 Cardiac tamponade
 Circulatory failure
Principle of repair
 Excision of intimal tear
 Obliteration of entry into FL
 Reconstitution of aorta with interposition
graft +/- coronary reimplantations
 Restoration of aortic valve incompetence
 Valve resuspension
 Aortic valve replacement
 Aortic root replacement
European Society of Cardiology task force
on acute type A Dissection
Operative mortality
 Operative mortality in experienced centers
with large surgical series varies widely
between 15%-35%, still below the 50%
mortality with medical therapy
General considerations
 Establishing CPB in traditional way.
 Rt radial a. line/ femoral a. line opposite to
cannulation site.
 Routine TEE
 If FEM-FEM bypass is chosen.
 CFA with the most normal pulse
 CFV on the right should be used ( easily
positioned to RA )
General considerations
 If circulatory arrest is needed, the core temp
should be lower to less than 20 celsius with
good LV venting.
 If aortic cross clamping is planning, clamp
should be placed several centimeters
proximal to innominate artery.
AHA Guidelines 2010
 Treatment acute type A Dissection
 All of aneurysmal aorta and the proximal extent of
the dissection should be resected.
 A partially dissected root may be repaired by
aortic valve resuspension.
AHA Guidelines 2010
 Patients with Type A Dissection
 Extensive aortic root dissection should be treated
with aortic root replacement with a composite
graft or with a valve sparing root replacement.
 In DeBekey Type 2 dissection the entire dissected
aorta should be replaced
Arterial Access for Cannulation
 Possible cannulationtion sites
 Femoral cannulation
 Right axillary artery
 Left common carotid artery
 Direct cannulation of aorta by TEE control
 Direct cannulation( cut open under visual
control)
 Transapical cannulation.
Axillary Cannulation
Axillary Cannulation
Advantages
Disadvantages

Antegrade perfusion.
 Time consuming.

No manipulation of the ascending
aorta.
 Impossible to CNS

Recomended over femoral
cannulation as prophylaxis against
malperfusion, lower extrmity
ischemia,retrograde dissection and
retrograde embolization of debris
perfusion if dissected.
 Brachial plexus injury.
 Vascular complication.
Axillary artery cannulation in type A aortic dissection
operations. J Thorac Cardiovasc Surg 1999
Axillary cannulation in acute ascending aortic dissections
Ann Thorac Surg 2000
Left Common Carotid Artery Cannulation for Type A
Aortic Dissections
 For cases that neither
right axillary artery nor
femoral artery can be
used

Abdominal aortic stenosis/
dissection both axillary arteries
Tex Heart Inst J. 2003; 30(2): 128–129
 Useful in all patients with acute
type A dissection.
 A major advantage is quicker
than others conventional
methods as no purse-strings or
additional dissection is required.
Surgical options for repair
 Supracommissural ascending aorta
replacement.(ascending aortic replacement)
 Composite conduit root replacement.
 Aortic valve-sparing root replacement.
 ± Hemiarch Replacement
 ± Total Arch Replacement
 ±Hybrid-Procedures ( Frozen-elephant trunk)
Bentall AVR
 Straightforward ( standard
technique)
 Shorter cross-clamp and bypass
time compared to valve sparing
operations.
Potential rationale for Valve-Sparing
Root Replacement

Excellent aortic valve function with
physiological hemodynamics
(Avoidance of PPM)

Lifelong good functionality (
Avoidance of reoperations)

Avoidance of prosthetic valve
related complications.
Absolute Contraindications for
Valve-Sparing Root Replacement
 Advanced degenerative calcification of the
aortic valve.
 Overstretched and thin cusps with stress
fenestrations and perforations.
 Acute infective endocarditis.
Relative Contraindications for
Valve-Sparing Root Replacement
 Patients who are in need of concomitant
procedures, who have impaired left
ventricular function.
 Patients who are elderly and frail and might
not tolerate extended cross-clamp and
bypass times.
 Lack of surgical experience.
What is the better choice for acute type A dissection
Bentall vs VSSR
Author
N
Mean
B/VSSR f/u
survival
Event free
survival
Bernhard A., Reichenspurner
et al.
2011
30/58
14Y-87% B
14Y-89%VSSR
14Y-48% B
14Y-44% VSSR
3.2 y
Freedom from
Reoperation
Bekkers JA, Boggers Ad et al
2012
75/157
7.2 Y
Overall 10y53.4% without
significant
difference
10y-100% B
10Y-85% VSSR
without
significant diff.
Subramanian S, Mohr FW et
al 2012
130/78
7.2Y
Overall 8y-55% Overall 8y-95%
without
without
significant diff significant diff.
How to deal with the Arch?
 The false lumen( DeBakey 1) in the arch and
descending aorta remains untreated,
potentially resulting in
 Aneurysmal(thoraco-abdominal) formation 10%
 Rupture
 Malperfusion
 Redo-surgery
10%
10-30%
?%
Kirsch M, et al. JTCVS 2002
Mehta R, et al. Circulation 2002
Total Arch Replacement in
Acute Type A Dissection
 Radical approach : resection of all diseased
tissue
 High risk
 High mortality
 Increased rate of stroke
 Lower reoperation rate
 Improved event free long term survival
CNS Protection
 Class 1
 A brain protection strategy……should be a key
element of the surgical, anesthetic and perfusion
techniques…….(Evidence: B)
 Class 2a
 Deep hypothermic circulatory arrest, and selective
antegrade brain perfusion are techniques that
alone or in combination are reasonable to
minimize brain injury……. Institution experience is
an important factor……( Evidence: B)
AHA Guidelines 2010
How to protect the brain?
How to protect the brain?
 “bilateral antegrade cerebral perfusion is
superior to any other method of brain
protection”
 Preservation of intracellular pH and energy stores
 Neurological deficit and cognitive dysfunction is
lowered compared to other methods.
 Allow extended repair with prolonged perfusion
time.
 Monitoring is mandatory (NIRS)
Randall B Griepp. J Thorac Cardiovasc Surg 2011
Near Infrared Spectroscopy (NIRS) Monitoring
 Continuous monitoring of regional cerebral
oxygen saturation (rCSO2).
 Under selective antegrade cerebral perfusion a drop of
rCSO2 of 30% of baseline values require immediate
control of perfusion modalities.
How much should we resect?
 An aggressive surgical approach, including a
full root or hemiarch replacement, is not
associated with increased operative risk and
should be considered when type A dissections
extensively involve the valve, sinuses or arch.
Better survival with extended approach
Surgical extent to the Arch
Total arch replacement
Kasui et al. J Thorac Cardiovasc Surg 2000
German Registry for Acute Aortic Dissection type A
(GERRAADA)
658 PATIENTS
Hemiarch
Total Arch
P value
30 d mortality
18.7%
25.7%
0.067
Neurological
deficit
13.6%
12.5%
0.78
Malperfusion
8.4%
10.7%
0.53
Is Arch Replacement
beneficial?
 No differences between isolated ascending
replacement and ascending + arch
replacement in the literature with regard to
 long term survival and freedom
from reoperation
Eleftriades et al.J Thorac Cardiovasc Surg 2005
The fate of the distal aorta after repair of
acute type A aortic dissection
Conclusions: Growth of the distal aorta after
repair of acute type A dissection is typically
slow and linear. Distal reoperation is
uncommon, and late risk of death is
approximately twice that of a healthy
population.
Halstead.
JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY
Volume:133 Issue:1 Pages:127-U102 DOI:10.1016/j.jctvs.2006.07.043
Published:JAN 2007
Hybrid procedure with
Frozen Elephant Trunk
Patients with type A acute aortic
dissection presenting with major brain
injury: should we operate on them?
Of 1873 patients with type A acute aortic
dissection enrolled in the International Registry
for Acute Dissection
Postoperatively, cerebrovascular accident and coma resolved in 84.3% and 78.8% of cases, respectively. On logistic
regression analysis, surgery was protective against mortality in patients presenting with brain injury (odds ratio 0.058; P <
.001).
The 5-year survival of patients presenting with cerebrovascular accident
and coma was 23.8% and 0% after medical management versus 67.1%
and 57.1% after surgery (log rank, P < .001), respectively.
J Thorac Cardiovasc Surg.2013