Aortic Disasters

Diagnosis, Imaging Techniques and

Management

Eric R. Snoey, MD

Alameda County Medical Center

Oakland, CA

Its 2:00 AM ….....

• 64 yo female presents with 4 hours of R flank pain,

nausea and fatigue. In general, the patient states that she

feels lousy. No amount of coaxing, coaching, cajoling

or thinly veiled physical threats are successful in

obtaining more information.

• ROS: no CP,SOB PmHX: NIDDM, smoking

• PE: Obese, anxious, uncomfortable

– VS: 150/80, 110, 16, 97.6

– Chest/Card: normal

– Abd: no consistent pain, guarding or rebound

Case 1 (cont)

• Differential: MI, PE, Chole, Renal stone,

AAA, Mesenteric ischemia

• Laboratory, U/A, Chest X-ray, ECG = nl

Becoming upset the patient says -

“You’re stalling, you don’t know what’s going on” -

Insert image of ruptured AAA

Definitions…..

• Aneurysm: localized dilatation of the entire

vessel wall involving all three layers

• Dissection: hematoma within the arterial media

causing a lengthwise separation

• Aortic Transection: traumatic tear of aorta

usually at lig arteriosum

Normal Dimensions: 2.5 cm, or 1.5 Xs diameter at renals

Epidemiology

• Incidence: 2-4% of population over age 50

• Avg age of dx 65 years, rare before age 50

• Male >>> female

• 98% infra-renal

• Associated arteriosclerotic disease

Smoking, HTN, Diabetes, family history,

Pathophysiology

• Pressure wave effects

• Mural ischemia –

increased fibrosis, less

elasticity

• Genetic predisposition

– Marfans, Erlos Danlos

Physical and hemodynamic factors

Complications/Natural Hx

• All AAAs will rupture

(if given time…….)

– Retroperitoneal,

– Intraperitoneal,

– Into GI tract,

– Into IVC

• Thromboembolic

Natural Hx (cont)

• Enlargement unpredictable

– yearly rate varies from -0.8 cm to 3.7 cm

• Risk of rupture increases as aneurysm size

increasesThere is effective no “safe” size

Size(cm) Ruptured Unruptured Total %Ruptured

_________________________________________________

<4 19 182 201 9.5%

4-5 15 49 64 23%

5-7 21 62 83 25%

7-10 26 37 68 45%

>10 26 17 43 60%

Natural Hx (cont)

• Risk of rupture……

– < 4.0 cm < 5% rupture at 5 years

– 4 - 5 cm 3-12% rupture at 5 years

– > 5 cm 21-41 % rupture at 5 years

Elective surgical risk < 5%, Mortality if ruptured = >60%

Early Diagnosis and surgical repair

represents only means of impacting

survival statistics

Presentation (un-ruptured)

• Symptoms:

– sensation of abdominal fullness, pulsations

• Signs:

– pulsatile, expansile abdominal mass

– abdominal bruit

• Thromboembolism

– “blue toe” syndrome, diminished pulses LE

Most are asymptomatic……...

Presentation (ruptured)

• Classic Triad ( < than 30% of patients )

– Back, Abdominal, Flank Pain

– Pulsatile abdominal Mass

– Hypotension

• May mimic many other disorders

– 24-42% misdiagnoses on 1st presentation (2X

mortality rate)

Misdiagnoses

GI

Renal colic

sepsis

MVA

Back pain

MI

Diverticulitis

miscellaneous

GI bleed

Unusual Presentations

• Chest pain

• Groin pain

• Syncope

• Bloody stool

• CHF

• Absent classic triad

– (2/3 of cases)

• Thrombo-embolism

• T 10-12 paraplegia

(sacral sparing)

• Hematuria

Symptoms Signs

Fistula

Diagnosis

• PE findings subtle and unreliable

• Palpable mass:

– Overall: 68% sens, 75% specific

– Sensitivity = 82% if AAA > 5.0cm

– 53% if abdominal girth > 100cm

Physical Exam

“ Given the prevalence (up to 4%) of AAA and high

morbidity associated with misdiagnosis, the

physical examination is inadequate to exclude the

diagnosis of AAA in any patient

reasonably considered to be at risk…….”

Image patients at risk !

Plain radiography

• 55% - 85% sensitive

for AAA

– Curvilinear calcifications, loss of psoas/renal shadow, renal displacement

– Best view is lateral L/S spine

Never use plain films to exclude AAA

! - best indication: evaluation of

! ! alternative diagnoses

Ultrasound

• Bedside, immediate,

time efficient screening

test (stable and

unstable patients)

• 100% sensitive (if

technically adequate)

• Look for alternative

etiologies

• Obesity/bowel gas:

obstacles to adequate

study

• No information on if

ruptured/complication

Advantages Disadvantages

CT

• Highly sensitive and accurate

• Offers detailed info: rupture ?, branch vessel

involvement, mural thrombi (particularly with

CTA, MSCT)

• May offer alternative diagnosis

• Disadvantage:

– Move to CT scanner, dye load and radiation

Indication: stable symptomatic patient or unstable patient in

! ! whom the diagnosis remains in doubt

Angiogram

• Less sensitive and accurate than either US or

CT

– False negatives due to mural thrombi

• Costly, time consuming, invasive

Case 2….

• 67 yo male presents with cough, fever and

sore throat….

• PE: VSS

– Abd: prominent, pulsatile, mid abd mass, non

tender

• Bed side US = AAA

Management

Asymptomatic patients

AAA < 4 cm - require Q 6 month follow up- begin HTN therapy, stop smoking, add B-blocker- operate when 5.5 cm or becomes symptomatic

AAA > 5.5 cm : most should undergo repair unless:

! - risk of OR > observation (CHF, COPD, CVA)

! - non AAA life expectancy < 2 years

Management

AAA 4 - 5.5 cm: controversial zone

Two studies (NEJM 5/2002), ~ 1700

patients with aneurysms 4 - 5.5 cm

randomized to immediate repair vs

surveillance with repair only if:

-Increase 0.7 cm in 6 months,

-1.0 cm in one year,

-Become symptomatic or

-Reach 5.5 cm.

Results: no difference in survival, 30% fewer surgeries and hospitalizations in surveillance groupConsider earlier surgery in women due to higher rupture risk

Management (cont)

• ED management strategy

– Expedited diagnosis ( US vs Helical CT)

– Blood pressure control (B-blocker + Nipride vs

Labetalol

– Prep for operative

• T&C, IV access, ECG, Surgical consultation

Hemodynamically stable, SymptomaticNew or changing symptoms

= Imminent if not acute rupture

Management (cont)

• IVF, T&C,

• Time to cross-clamp of aorta only

controllable variable

– Delays lead to increased mortality

– Only reasonable diagnostic test is US

• Negative lap - 75% had serious abd

abnormality requiring laparotomy

Unstable patient…...

Operative Management

Endovascular Grafts

- less invasive

- less expensive

- shorter life span

- best in higher surgical

! risk patients

-Many recent concerns

about failure rates..

Another Case• 32 yo male presents with sudden onset dysarthria

and R hand numbness/weakness. Noted

progressive shortness of breath over the past

several hours. He denies chest pain. + History of

hypertension and cocaine abuse - most recently

today !

• PE: VS 110/40, 130, 24, 37, pulse ox = 98%

– Chest: clear

– Card: tachycardia,, II/IV diastolic murmur

– Neuro: Right facial and UE plegia

Aortic Dissection

Classification (Stanford)

Type A Type B

Aortic Dissection

Epidemiology

• Long standing HTN (not atherosclerosis)

• Elastin and connective tissues disorders

– Marfan’s, Cystic medial necrosis, Pregnancy,

• Cardiac Disorders

– Coarctation, Bicuspid aortic valve

• Trauma

• Acute stressors

– Cocaine/Met amphetamine

~ 0.5 -1% of MI rate

Age-related Risk Factors associated with

aortic dissection

Risk factor AD > 40 y AD < 40 y P value

Marfan syndrome 2% 49% <.001%

Hypertension 74% 35% <.001%

Bicuspid valve 3% 16% <.001%

Prior aortic valve

replacement

5% 13% <.01%

Atherosclerosis 31% 2% <.001%

95% of Aortic Dissection occurs > 40 yo

Acute Aortic Syndrome

• Classical AD– True and false lumen

– Longitudinal spread

• Intramural Hematoma– Localized hematoma

– No Doppler flow/contrast on CT

• Penetrating Aortic Ulcer– Typically descending aorta

– Rupture atherosclerotic plaques

Haro et al. EM Clinics, Nov 2005

10%20%

70%

Natural history

• 1-2%/hour mortality rate (untreated),

– 50% at 30 days

• Type A: Mortality 10% at 24 hours,

– 30% at 30 days

• Type B: Mortality 10% at 30 days if

uncomplicated

*International Registry of Aortic Dissection

PresentationPain +/- other symptoms: neurologic, limb ischemia, syncope, SOB (CHF, Pericardial Effus)

Pain Type

Chest anteriorChest PosteriorAnt & PostNeckAbd

SharpTearing/RippingMigratory

Proximal

65%10%8%8%6%

64%50%16%

Distal

27%57%16%0%4%

68%52%19%

*International Registry of Aortic Dissection

PresentationPhysical findings of AD present in < 50% of cases

Signs

Hypertension

Hypotension

Pulse Deficit

AI Murmur

Neuro Deficit

Proximal

35%

12%

18%

44%

6%

Distal

70%

2%

9%

12%

2%

*International Registry of Aortic Dissection

Mechanism of obstruction

Method of pulse deficit and/or neuro sxs

Diagnosis

• Clinical Suspicion/Appropriate patient type

PLUS

– Sudden, atypical or migratory pain, tearing,

– mixed cardiovascular/neuro presentations

• Physical Exam:

– Excludes alternative diagnosis

– AI murmur, Pulse deficits

Diagnosis can not be made without imaging study

Chest radiography

65% sensitive

Widened knob

Double wall sign

Effusion or cap

Wide mediastinum

CT

MRI

Advantages: accurate, excellent anatomic detail

Disadvantages: slow,unavailable, costly

TEE

Advantages: accuracy, intimal tear localization, dx of

AI and pericardial effusions

Disadvantages: requires sedation and cardiologist

Serologic screening

• Smooth muscle myosin heavy chain (SMMHC)– 90% sensitive in first 3 hours (IRAD patients), 44%

sensitive later

• sELAF : soluble elastin fragments.– Sensitivity high if true and false lumen communicate,

poor in setting of IMH

– Poor NPV

• D-dimer: 100% sensitive, 68% specific– Small, retrospective study, High NPV but low

specificity means many unnecessary imaging studies

•Shinohara et al, Arterio Throm Vasc, 2003, ** Weber et al. Chest May 2004,

•Katoh and Suzuki Circulation 2004

Treatment

Stop extension of dissection

Control dP/dt - ie contractility of the aorta

Decrease blood pressure and decrease heart rate

Target: lowest blood pressure that allows for normal mental status, SBP ~ 100-110

Pain control

Stabilization for surgery…… (Type A)

DrugsGoal is reduction of Force and Rate of contraction

Drug

Nipride

Propranolol(Esmolol)

Labetalol

Trimethaphan

Fenoldopam

Blood press Contractility

Variant mgt scenarios

• Dissection + Hypotension/CHF: Diff Dx– AI: gentle rate control, early surgery

– Pericardial tamponade: IVF, early surgery (pericardiocentesis – worse outcome..)

– MI: gentle rate control - early surgery, (avoid ASA, antithrombotics)

• Dissection + Neuro deficits– Obstructive: gentle pressure and rate reduction (hold if

neuro deficit widens), early surgery

Surgery

Reserved for most (80%)Type A

and any (20%) Type B

with vascular or neurologic

complications

Isolated Arch dissections –

medical Tx

Uncomplicated Type B treated

medically

- B-blockers/anti-HTN

vs endovascular

grafts and stents

Noninvasive Endografts, Stents and Fenestration