10) Aortic dissection – classification, clinical presentation, diagnosis, management.

Question 1

what is aortic dissection ?

Answer 1

a tear in the intima (inner layer ) hematoma in the media - creating a false lumen

Question 2

where does aortic dissection usually take place ?

Answer 2

Ascending aorta: ∼ 65% of cases

Descending aorta, distal to the left subclavian artery: 20%

Aortic arch: 10% of cases

Abdominal aorta

Question 3

what is the etiologyy of aortic dissection ?

Answer 3

hypertension

trauma - deceleration motor vehicle incident

vasculitis with aortic involvement - syphilis

use of amphetamines / cocaine

atherosclerosis

congenital - marfan and ehlers danlos syndrome
bicuspid aortic valve

Question 4

what is the classification of aortic dissection ?

Answer 4

stanford classification

stanford type A
any dissection involving the ascending aorta
defined as proximal to the brachiocephalic artery (can progress into aortic arch )

= needs surgery

stanford type B
any dissection not involving the ascending aorta -
such as descending aorta - distal to the left subclavian artery
= can be managed by beta blockers and vasodilators

Question 5

what is the complication of stanford type a aortic dissection ?

Answer 5

myocardial infraction - CA occlusion

aortic regurgitation - extension of dissection into aortic valve

cardiac tamponade

pericarditis - extension of dissection to pericardium

stroke - extend of dissection into carotidis

internal bleeding

Question 6

what creates a false lumen in dissection ?

Answer 6

transverse tear in the intimal

Question 7

what is the clinical features of aortic dissection ?

Answer 7

sudden and severe ripping pain - in the anterior of chest for ascending aorta

or back / inter scapular / retrosternal - in descending aorta

radiate to neck and jaw - aortic arch affected and extending into he greater vessels

abdomen or periumbilical colicky pain - for abdominal dissection

hypertension (due to underlying hypertension and severe pain) or hypotension (hemotoma or cardiac tamponade)

ASYMETRICAL BLOOD PRESSURE and PULSE readings between limbs

syncope , diaphoresis , confusion

aortic regurgitation murmur in ascending aorta

Question 8

how can we assess the risk for aortic dissection

Answer 8

ADD-RS

every category gets 1 score

conditions : 
marfa 
family history off aortic disease 
known aortic disease 
recent aortic manipulation 
thoracic aortic aneurysm 

pain characteristics :
abrupt onset
severe intensity
ripping and tearing

examination findings:
pulse deficit , systolicc BP different , focal neurological deficit

new aortic murmur with pain

hypotension or shock

2-3= high risk - definite imaging needed

0-1 - low to moderate risk - egg and lab studies and chest x ray

Question 9

what are the diagnostic tool for aortic dissection ?

Answer 9

ECG should be ordered for all
- left ventricular hypertrophy finding
non specific changes - ST depression and T wave changes
ST elevation due to coronary artery occlusion

=========

lab study
d dimer test , coagulation tests
end organ damage- troponin , BMP

=========

chest X ray
normal chest x ray do not rule out aortic dissection
Widened mediastinum at the level of the aortic knuckle (where the aortic arch curves posterolaterally to become the descending artery )

double aortic contour

Mediastinal mass

deviation of mediastinal structures such as trachea and esophagus

============
CT - GOLDEN STANDARD
or

transesophgaeal echo - in unstable patients , and INTRAOPERATIVE VISUALISATION
RENAL INSUFFICIENCY FOR CONTRAST
or MRA

Question 10

what are the CT findings ?

Answer 10

intimal dissection flap

double lumen

aortic dilations

aortic hematoma - high attenuated

Question 11

in CT how can we differentiate between the true and the false lumen ?

Answer 11

true lumen:
often compressed by the false lumen and the smaller of the two
outer wall calcifications (helpful in acute dissections)

false lumen
beak sign

Question 12

what are the indication for surgery ?

Answer 12

Surgical therapy
polyester graft implantation:

All patients with Stanford A dissection

h Stanford B dissection who develop complications such as :

• End-organ damage (ischemia)
• Hypotension
• Persistent severe chest pain or hypertension
• Propagation of dissection
• Expanding aneurysm

============

GIVE morphine for pain

Question 13

in stanford type b what is the medical management ?

Answer 13

hypotensive
Hemodynamic support: target MAP of 70 mm Hg or euvolemia

IV fluids
Vasopressor support: if the patient remains hypotensive
- Norepinephrine
- Phenylephrine
Inotropes should be avoided increase sheer stress on aortic wall

hypertensive
target SBP 100–120 mm Hg and HR ≤ 60 beats per
Start with IV beta blocker before vasodilators to avoid reflex tachycardia
Esmolol
Labetalol

then Followed by vasodilator (e.g., IV sodium nitroprusside

if bb contraindicated CCB

always continue to monitor urine output

Question 14

what type of therapy should we avoid aortic dissection ?

Answer 14

thrombolytic therapy

Question 15

MOST IMPORTANT COMPLICATION OF BOTH

AND what are stanford type b complications ?

Answer 15

AORTIC RUPTURE - HYPOVOLEMIC SHOCK

Arterial occlusion followed by ischemia of the:
Celiac trunk, superior/inferior mesenteric artery → acute abdomen, ischemic colitis

Renal arteries → acute renal failure (oliguria, anuria)

Spinal arteries → weakness of lower extremities or acute paraplegia

Complete occlusion of the distal aorta → Leriche syndrome (aortoiliac occlusive disease)