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Approach to the Critical Patient
Immediate priorities
Life threats at presentation
Untreated mortality 1 to 2 percent per hour in first 24 hours
Surgical emergency
Cardiothoracic surgery activation before confirmatory labs
Hemodynamic collapse mechanisms
Cardiac tamponade from rupture into pericardium
Free rupture into pleura or mediastinum
Acute severe aortic regurgitation
Malperfusion threats
Coronary ostial compromise causing acute MI
Carotid involvement causing stroke
Spinal malperfusion causing paraplegia
Airway and breathing
Oxygenation target
SpO2 94 to 98 percent
Avoid hypoxemia worsening malperfusion
If pulmonary edema from acute AR, prepare ventilatory support
Diastolic decrescendo murmur
Rising work of breathing
Circulation
Two large bore IV lines
Bilateral upper limb access
Account for pulse deficit limb
Arterial line for accurate titration
Cannulate limb with higher pressure
Continuous beat to beat monitoring
If hypotensive, suspect tamponade or rupture
Bedside echo for pericardial effusion
Avoid aggressive fluid before source control
Hemodynamic goals
Anti-impulse targets
Heart rate 60 to 80 beats per minute
Reduces aortic wall shear stress dP/dt
Beta blockade before any vasodilator
Systolic blood pressure 100 to 120 mmHg
Lowest pressure maintaining end organ perfusion
Mentation and urine output as perfusion markers
If SBP remains above 120 mmHg after rate control, add vasodilator
Nicardipine or nitroprusside infusion
Never vasodilator alone
Monitoring bundle
Continuous cardiac monitor and pulse oximetry
Arrhythmia surveillance
Tamponade electrical alternans watch
Bilateral blood pressure and pulses
Interarm differential above 20 mmHg
Re-check after each titration
Team activation and decision points
Immediate consultation triggers
Cardiothoracic surgery on suspicion
Do not delay for D-dimer or troponin
Definitive surgical repair is the only durable therapy
Anesthesia and ICU
Operative planning
Postoperative critical care bed
Transfer decision
If no on-site cardiothoracic capability, transfer to high-volume aortic center
Stabilize anti-impulse therapy before transport
Accepting surgeon contact before departure
If hemodynamically unstable, resuscitate toward operative readiness
Activate massive transfusion protocol
Type and crossmatch en route
History
Pain characteristics
Onset and quality
Abrupt maximal-at-onset pain
Thunderclap character
Classically tearing or ripping
More commonly reported as sharp or stabbing
Pain location
Anterior chest pain most common in Type A at 71 percent
Back pain in 47 percent
Abdominal pain in 21 percent
Migratory pattern
Pain moves as dissection propagates
Interscapular radiation
Distinguishing features
Absence of pleuritic quality
Helps separate from pericarditis
Helps separate from PE
Absence of positional component
Argues against pericarditis
Absence of gradual crescendo pattern
Argues against acute coronary syndrome
Associated symptoms
Cardiovascular and neurologic
Syncope present in about 13 percent
Suggests tamponade
Suggests cerebral malperfusion
Focal weakness or numbness
Carotid involvement
Spinal cord malperfusion
Dyspnea and diaphoresis
Acute AR pulmonary edema
Sense of impending doom
Malperfusion symptoms
Abdominal pain out of proportion
Mesenteric ischemia
Bloody stools
Oliguria
Renal artery involvement
Cool painful limb
Iliofemoral extension
Triggers and risk factors
Acute triggers
Extreme exertion or weightlifting
Valsalva maneuver
Acute blood pressure surge
Stimulant exposure
Cocaine
Amphetamines
Recent aortic manipulation
Prior cardiac surgery
Catheter intervention
Chronic risk factors
Hypertension in 66 to 86 percent
Single most common risk factor
Poorly controlled disease
Connective tissue disorders
Marfan syndrome FBN1
Loeys-Dietz syndrome TGFBR1 and TGFBR2
Vascular Ehlers-Danlos COL3A1
Turner syndrome
Bicuspid aortic valve
In patient or family
Associated aortopathy
Pre-existing aortic aneurysm or prior aortic surgery
Coarctation repaired or unrepaired
Prior valve replacement
Obstructive sleep apnea associated with 60 percent increased risk
Nocturnal pressure surges
Family history
First-degree relative aortic dissection
6-fold increased risk
Heritability estimated at 57 percent
Nonsyndromic familial aneurysm and dissection genes
ACTA2 MYH11 SMAD3 PRKG1 MYLK
13 to 19 percent of nonsyndromic patients have affected relatives
Physical Exam
Vitals and perfusion
Blood pressure assessment
Hypertension common at presentation
Sympathetic surge
Chronic uncontrolled disease
Hypotension is an alarm finding
Rupture
Tamponade
Severe AR
Interarm differential above 20 mmHg
High-risk finding
Arch branch vessel involvement
Pulse examination
Bilateral radial femoral and pedal pulses
Pulse deficit present in about 30 percent
Asymmetry localizes branch involvement
Cool mottled or pulseless limb
Limb malperfusion
Cardiac and systemic exam
Cardiac auscultation
New diastolic decrescendo murmur
Acute aortic regurgitation
Wide pulse pressure
Muffled heart sounds
Pericardial effusion
Pulsus paradoxus above 10 mmHg
Tamponade physiology
Inspiratory SBP drop
Neurologic examination
Focal deficit
Hemiparesis or hemisensory loss
Altered consciousness
Paraplegia
Anterior spinal artery malperfusion
Abdominal and extremity exam
Abdominal tenderness
Mesenteric ischemia
Pulsatile mass if abdominal aorta involved
Marfanoid habitus
Tall stature and arachnodactyly
Pectus deformity
Lens subluxation especially under 40 years
PITFALLS
Anchoring errors
STEMI pattern from coronary ostial compromise
Usually RCA causing inferior leads
Obtain bedside echo before cath activation
Painless dissection in about 6 percent
Isolated stroke presentation
Isolated syncope presentation
Underweighting exam clues
Normal chest x-ray does not exclude dissection
Maintain imaging if suspicion persists
Pulse deficit may be intermittent
Re-examine serially
Differential Diagnosis
Life-threatening mimics
Cardiopulmonary emergencies
Acute coronary syndrome and STEMI
ICD-10 I21.9
Crescendo pain not maximal at onset
Most common misdiagnosis
Pulmonary embolism
ICD-10 I26.99
D-dimer elevated in both PE and dissection
CTA distinguishes
Tension pneumothorax
Unilateral breath sounds
Tracheal deviation
Pericardial and esophageal
Pericarditis and tamponade
Positional pleuritic pain
Diffuse ST elevation and friction rub
Tamponade may be a complication of dissection
Esophageal rupture Boerhaave
Post-emesis onset
Subcutaneous emphysema
Other considerations
Vascular and valvular
Acute aortic regurgitation other causes
Endocarditis
Prosthetic valve failure
Stroke when neurologic deficit dominates
Consider dissection in young stroke
Avoid thrombolysis before excluding dissection
Lower acuity mimics
Musculoskeletal chest pain
Diagnosis of exclusion
Reproducible on palpation
Acute aortic syndrome spectrum
Intramural hematoma
Penetrating atherosclerotic ulcer
Laboratory Tests
Diagnostic and prognostic labs
D-dimer
High sensitivity around 94 percent
Value below 500 ng/ml in low-risk patient effectively rules out dissection
Value above 1600 ng/ml strongly suggests acute aortic syndrome
Limitations
Not a standalone rule-in
Combine with risk score
Troponin
May be elevated from coronary malperfusion or demand ischemia
Elevated troponin does not exclude dissection
Must not delay imaging
Alerting triad for acute aortic syndrome
Normal ECG
Normal troponin
Elevated D-dimer
Perfusion and preoperative labs
Malperfusion markers
Lactate
Elevated in mesenteric or limb ischemia
Metabolic acidosis on ABG
Creatinine and electrolytes
Renal malperfusion
Baseline for contrast
Liver function tests
Hepatic malperfusion
Preoperative panel
Complete blood count
Anemia suggests hemorrhage
Baseline before surgery
Coagulation studies
PT INR and PTT
Fibrinogen
Type and crossmatch
Anticipate massive transfusion
Multiple units available
Diagnostic Tests
Scoring Systems
Aortic Dissection Detection Risk Score ADD-RS
Three category framework scored 0 to 3
High-risk predisposing conditions
High-risk pain features
High-risk exam findings
Interpretation with D-dimer
ADD-RS at most 1 plus D-dimer below 500 ng/ml gives sensitivity 93 to 99.8 percent
ADD-RS of 2 or more warrants definitive imaging
Evidence
Endorsed by 2022 ACC/AHA aortic disease guideline
Supported by 2021 chest pain guideline
ECG as adjunct
Neither sensitive nor specific but essential for ACS mimicry
About 60 percent of Type A have abnormal ECG
ST depression or T-wave inversion in about 47 percent
High-risk ECG findings
ST elevation in 4 to 22 percent may mimic STEMI
ST elevation in aVR associated with mortality OR 4.85 to 5.30
Low voltage or electrical alternans suggests effusion
MRI
MR angiography role
High diagnostic accuracy
Sensitivity and specificity above 95 percent
No ionizing radiation or iodinated contrast
Acute setting limitations
Long acquisition time impractical for unstable patients
Limited monitoring access in scanner
Preferred indications
Iodinated contrast allergy
Surveillance follow-up imaging
Younger patients limiting radiation
Contraindications
Hemodynamic instability
Cannot monitor or resuscitate adequately
Non-compatible implants
Older pacemakers
Ferromagnetic devices
CT
CT angiography first-line gold standard
Coverage chest abdomen and pelvis
Arch vessels to iliacs
ECG gating reduces motion artifact
Performance characteristics
Sensitivity approaching 100 percent
Specificity approaching 100 percent
Key findings
Intimal flap with true and false lumen
Entry tear location and extent
Branch vessel involvement
Pericardial effusion and malperfusion
Guideline and practical notes
2022 ACC/AHA recommends CTA as first-line imaging
Class I recommendation
Rapid availability advantage
Contrast considerations
Renal function review
Do not delay surgery in unstable patient for creatinine
Ultrasound
Transesophageal echocardiography
Excellent for ascending aorta and valve
Bedside in unstable patients
Intraoperative assessment
Assesses operative anatomy
Valve competence
Coronary ostia
Distal extent of flap
Transthoracic echo and POCUS
Four findings suggesting Type A dissection
Aortic intimal flap
Aortic root enlargement
Aortic regurgitation
Pericardial effusion
Performance and limits
Sensitivity about 78 to 87 percent
Cannot rule out dissection alone
Useful for rapid triage in unstable patients
Disposition
Level of care
Universal admission
All confirmed or suspected Type A require admission
No outpatient management pathway
Operative repair is standard of care
ICU admission
Continuous hemodynamic monitoring
Postoperative critical care
Admission and escalation criteria
Confirmed Type A dissection
Immediate operative planning
Anti-impulse therapy continuation
Complicated features
Hemodynamic instability
Malperfusion syndrome
Tamponade or new neurologic deficit
Consultation and transfer
Surgical consultation
Immediate cardiothoracic surgery on suspicion
Do not delay for confirmatory labs
Parallel resuscitation and imaging
Multidisciplinary discussion when surgery prohibitive
Extreme frailty
Severe comorbidity burden
Transfer indications
Absence of on-site cardiothoracic capability
Transfer to high-volume aortic center
Stabilize before transport
Follow-up surveillance plan
CT or MRI at 1 month 6 months 12 months then annually
Lifelong imaging emphasized
Treatment
Immediate anti-impulse therapy
First-line intravenous beta blockade
Esmolol infusion
500 mcg/kg IV bolus over 1 minute
50 mcg/kg/min continuous infusion
Titrate by 50 mcg/kg/min to max 200 to 300 mcg/kg/min
Labetalol
20 mg IV bolus
Repeat 20 to 80 mg every 10 minutes
Or infusion 1 to 2 mg/min
Targets
Heart rate 60 to 80 beats per minute
Systolic blood pressure 100 to 120 mmHg
If beta blockers contraindicated
Non-dihydropyridine calcium channel blocker
Diltiazem IV
Verapamil IV
Indications
Severe reactive airway disease
Beta blocker intolerance
Adjunctive blood pressure and pain control
Vasodilators after rate control only
Nicardipine infusion
Start 5 mg/hr IV
Titrate by 2.5 mg/hr every 5 to 15 minutes to max 15 mg/hr
Nitroprusside infusion
Start 0.3 mcg/kg/min IV
Titrate to max 10 mcg/kg/min
Only after beta blockade to avoid reflex tachycardia
Pain control
Intravenous opioids reduce sympathetic drive
Fentanyl 25 to 50 mcg IV titrated
Morphine 2 to 4 mg IV titrated
Effect on wall stress
Lowers catecholamine surge
Supports rate and pressure targets
Contraindicated and avoid
Therapies to avoid
Vasodilator before beta blockade
Reflex tachycardia
Increased aortic wall stress
Anticoagulation and thrombolytics
Catastrophic if misdiagnosed as ACS or PE
Withhold until dissection excluded
Hemodynamic support cautions
If hypotensive, identify tamponade or rupture first
Bedside echo
Avoid over-resuscitation raising pressure
Blood products
Type and crossmatch early
Activate massive transfusion protocol if unstable
Definitive surgical management
Emergency open surgical repair
Standard of care Class I recommendation
Ascending aortic replacement with synthetic graft
Aortic valve resuspension or root replacement Bentall
Operative technique
Open distal anastomosis during hypothermic circulatory arrest
Hemiarch repair standard unless arch tear
Total arch replacement if arch aneurysm
Neuroprotection
Axillary cannulation preferred over femoral to reduce stroke
Antegrade cerebral perfusion during arrest
Special intraoperative scenarios
Preoperative nonhemorrhagic stroke
Surgery still reasonable and improves outcomes
Coronary ostial involvement
Assessed intraoperatively
Coronary angiography generally avoided preoperatively
Long-term medical therapy
Blood pressure control
Beta blockers first-line
Target SBP below 120 mmHg
Some guidelines target below 130 mmHg
ACE inhibitors or ARBs as adjuncts
Target below 120/80 mmHg
Statin if indicated
Risk reduction
Lifestyle
Smoking cessation
Avoid heavy isometric exercise and Valsalva
Genetic counseling
First-degree relative screening if under 60
Screening if features of genetic aortopathy
Special Populations
Pregnancy
Risk and physiology
Highest risk third trimester and peripartum
Hormonal aortic wall changes
Hemodynamic and volume stress
Associated aortopathy
Marfan syndrome
Bicuspid valve and coarctation
Management adaptations
Imaging
CT angiography with abdominal shielding when needed
MRI without gadolinium when stable
Anti-impulse therapy
Labetalol preferred
Avoid nitroprusside near term due to fetal cyanide risk
Delivery and surgery coordination
Cesarean before repair if viable fetus
Multidisciplinary obstetric and cardiac team
Geriatric
Presentation differences
Atypical features
Syncope or altered mentation
Less classic tearing pain
Higher complication rate
Greater baseline hypertension
More extensive atherosclerosis
Management considerations
Surgical risk assessment
Frailty and comorbidity weighting
Medical management only if prohibitive risk
Medication adjustments
Renal dosing of agents
Careful titration to avoid hypoperfusion
Pediatrics
Etiology and risk
Genetic aortopathy predominates
Marfan and Loeys-Dietz syndromes
Turner syndrome
Structural lesions
Bicuspid aortic valve
Coarctation of the aorta
Management adaptations
Weight-based anti-impulse therapy
Esmolol 100 to 500 mcg/kg IV bolus then 50 to 300 mcg/kg/min
Labetalol 0.2 to 1 mg/kg IV bolus
Imaging and surgery
CT or MR angiography with dose reduction
Referral to pediatric cardiac surgery center
Background
Epidemiology
Incidence and demographics
Stanford Type A is 59 to 67 percent of acute aortic syndromes
Defined by ascending aorta involvement
Regardless of primary tear site
Age and sex distribution
Peak incidence 60 to 70 years
Male sex about 65 to 70 percent
Patients under 40 more likely genetic aortopathy
Mortality burden
Untreated course
1 to 2 percent mortality per hour first 24 hours
Medical management mortality about 57 percent
Surgical outcomes
Surgical mortality decreased from 25 to about 18 percent
Best outcomes at high-volume centers
Pathophysiology
Mechanism of dissection
Intimal tear and false lumen
Blood enters medial layer
Propagation antegrade or retrograde
Medial degeneration substrate
Connective tissue gene defects
Chronic hypertensive wall stress
Complication pathways
Proximal extension
Coronary ostial occlusion causing MI
Aortic root dilation causing acute AR
Rupture into pericardium causing tamponade
Branch malperfusion
Static or dynamic obstruction
Cerebral mesenteric renal or limb ischemia
Therapeutic Considerations
Rationale for anti-impulse therapy
Reduce aortic wall stress
Lower dP/dt with rate control
Lower pressure with vasodilator after beta blockade
Sequencing principle
Beta blockade before vasodilator prevents reflex tachycardia
Pain control lowers sympathetic drive
Rationale for emergent surgery
Mortality time-dependence
Each hour of delay increases death risk
Surgery interrupts rupture and malperfusion cascade
Surveillance rationale
10 to 20 percent need reintervention within 10 years
About 50 percent lost to follow-up by 28 months
Patient Discharge Instructions
copy discharge instructions
Postoperative and long-term home care
Take all blood pressure medications exactly as prescribed
Keep blood pressure low as directed by your team
Attend all surveillance imaging appointments for life
Avoid heavy lifting straining and intense isometric exercise
Lifestyle and prevention
Stop smoking and avoid cocaine or stimulants
Limit caffeine and follow a heart-healthy low-salt diet
Ask family members about screening if a genetic cause was found
Return to ER immediately for red flags
Sudden severe chest back or abdominal pain
New weakness numbness vision change or trouble speaking
Fainting or near fainting
Cool painful or discolored arm or leg
Shortness of breath or very fast heartbeat
Follow-up
Keep cardiothoracic surgery follow-up appointments
Keep cardiology and blood pressure follow-up appointments
Bring an updated medication list to every visit
References
Guidelines and key sources
Major guidelines
2022 ACC/AHA Guideline for Diagnosis and Management of Aortic Disease
2024 EACTS/STS Guidelines for Acute and Chronic Aortic Syndromes
2010 ACCF/AHA Thoracic Aortic Disease Guidelines
2021 AHA/ACC Chest Pain Evaluation Guideline
Landmark reviews and studies
Carrel et al Acute Aortic Dissection Lancet 2023
Nienaber and Clough Management of Acute Aortic Dissection Lancet 2015
Mussa et al Acute Aortic Dissection and Intramural Hematoma JAMA 2016
Ren et al ADD-RS diagnostic accuracy meta-analysis PLoS One 2023
Coding standards
ICD-10 I71.00 dissection of aorta unspecified site
ICD-10 I71.01 dissection of thoracic aorta
SNOMED CT aortic dissection disorder concept
SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.