Aortic DissectionAortic Dissection

Jason S. Finkelstein, M.D.Jason S. Finkelstein, M.D.Cardiology FellowCardiology FellowTulane UniversityTulane University

8/11/038/11/03

OverviewOverview

• Incidence of aortic dissection is at least 2000 Incidence of aortic dissection is at least 2000 new cases per yearnew cases per year

• Peak incidence is in the sixth to seventh decadePeak incidence is in the sixth to seventh decade

• Men are affected twice as commonly as womenMen are affected twice as commonly as women

• Mortality in the first 48 hours is 1% per hourMortality in the first 48 hours is 1% per hour– Early diagnosis is essentialEarly diagnosis is essential

PathophysiologyPathophysiology

• The chief predisposing factor is The chief predisposing factor is degeneration of collagen and elastin in the degeneration of collagen and elastin in the aortic intima mediaaortic intima media

• Blood passes through the tear into the Blood passes through the tear into the aortic media, separating the media from the aortic media, separating the media from the intima and creating a false lumenintima and creating a false lumen

• Dissection can occur both distal and Dissection can occur both distal and proximal to the tearproximal to the tear

ClassificationClassification

• Debakey systemDebakey system– Type I Type I

• Originates in the ascending aorta, propagates to the Originates in the ascending aorta, propagates to the aortic arch and beyond it distallyaortic arch and beyond it distally

– Type IIType II• Confined to the ascending aortaConfined to the ascending aorta

– Type IIIType III• Confined to the descending aorta, and extends Confined to the descending aorta, and extends

distally, or rarely retrograde into the aortic archdistally, or rarely retrograde into the aortic arch

ClassificationClassification

• The Stanford systemThe Stanford system– Type AType A

• All dissections involving the ascending aortaAll dissections involving the ascending aorta

– Type BType B• All other dissections regardless of the site of the All other dissections regardless of the site of the

primary intimal tearprimary intimal tear

– Ascending aortic dissections are twice as Ascending aortic dissections are twice as common as descending common as descending

Predisposing factorsPredisposing factors

• Age, 60-80 yrs oldAge, 60-80 yrs old• Long standing history of hypertensionLong standing history of hypertension

– 80% of cases have co-existing HTN80% of cases have co-existing HTN

• Takayasu’s arteritisTakayasu’s arteritis• Giant cell arteritisGiant cell arteritis• SyphilisSyphilis• Collagen disordersCollagen disorders

– Marfan syndrome (6-9% of aortic dissections)Marfan syndrome (6-9% of aortic dissections)– Ehlers-Danlos syndromeEhlers-Danlos syndrome

Other Risk FactorsOther Risk Factors

• Congenital Cardiac AnomaliesCongenital Cardiac Anomalies– Bicuspid aortic valve (7-14% of cases)Bicuspid aortic valve (7-14% of cases)– Coarctation of the aortaCoarctation of the aorta

• CocaineCocaine– Abrupt HTN, due to catecholamine releaseAbrupt HTN, due to catecholamine release

• TraumaTrauma

• Pregnancy (50% of dissections in women <40 yrs)Pregnancy (50% of dissections in women <40 yrs)

• Iatrogenic (cardiac cath, IABP, cardiac surgery, s/p valve Iatrogenic (cardiac cath, IABP, cardiac surgery, s/p valve replacement)replacement)

Clinical SymptomsClinical Symptoms

• Severe, sharp, “tearing” posterior chest pain or Severe, sharp, “tearing” posterior chest pain or back pain (occurs in 74-90% of pts)back pain (occurs in 74-90% of pts)

– Pain may be associated with syncope, CVA, MI, or CHFPain may be associated with syncope, CVA, MI, or CHF– Painless dissection relatively uncommonPainless dissection relatively uncommon

• Chest pain is more common with Type A Chest pain is more common with Type A dissectionsdissections

• Back or abdominal pain is more common with Back or abdominal pain is more common with Type B dissectionsType B dissections

Physical ExamPhysical Exam

• Pulse deficitPulse deficit– Weak or absent carotid, brachial, or Weak or absent carotid, brachial, or

femoral pulses femoral pulses – these patients have a higher rate of these patients have a higher rate of

mortalitymortality

• Acute Aortic InsufficiencyAcute Aortic Insufficiency– Diastolic decrescendo murmurDiastolic decrescendo murmur– Best heard along the right sternal borderBest heard along the right sternal border

Clinical signsClinical signs

• Acute MIAcute MI– RCA most commonly involvedRCA most commonly involved

• Cardiac tamponadeCardiac tamponade• Pleural effusionsPleural effusions• Hypertension or hypotensionHypertension or hypotension• HemothoraxHemothorax• Variation in BP between the arms (>30mmHg)Variation in BP between the arms (>30mmHg)

• Neurologic deficitsNeurologic deficits– Stroke or decreased consciousnessStroke or decreased consciousness

Clinical SignsClinical Signs

• Involvement of the descending aortaInvolvement of the descending aorta– Splanchnic ischemiaSplanchnic ischemia– Renal insufficiencyRenal insufficiency– Lower extremity ischemiaLower extremity ischemia– Spinal cord ischemiaSpinal cord ischemia

DiagnosisDiagnosis

• Generally suspected from the history and PEGenerally suspected from the history and PE

• In a recent study in 2000, 96% of acute dissection In a recent study in 2000, 96% of acute dissection patients could be identified based upon a patients could be identified based upon a combination of three clinical featurescombination of three clinical features– Immediate onset of chest painImmediate onset of chest pain– Mediastinal widening on CXRMediastinal widening on CXR– A variation in pulse and/or blood pressure (>20 mmHg A variation in pulse and/or blood pressure (>20 mmHg

difference between R & L armdifference between R & L arm

• Incidence >83% when any combination of all Incidence >83% when any combination of all three variables occurredthree variables occurred

Differential DiagnosisDifferential Diagnosis

• Acute Coronary SyndromeAcute Coronary Syndrome

• PericarditisPericarditis

• Pulmonary embolusPulmonary embolus

• PleuritisPleuritis

• CholecystitisCholecystitis

• Perforating ulcerPerforating ulcer

Diagnostic TestsDiagnostic Tests

• EKGEKG– Absence of EKG changes usually helps Absence of EKG changes usually helps

distinguish dissection from anginadistinguish dissection from angina

– Usually non-specific ST-T wave changes seenUsually non-specific ST-T wave changes seen

• CXRCXR

• Cardiac EnzymesCardiac Enzymes

Chest X-RayChest X-Ray

• May show widening of the aorta with May show widening of the aorta with ascending aorta dissectionsascending aorta dissections

– Present in 63 % of patients with Type A Present in 63 % of patients with Type A dissectionsdissections

Diagnostic ImagingDiagnostic Imaging

• Not performed until the patient is Not performed until the patient is medically stablemedically stable

• Has been a dramatic shift from invasive to Has been a dramatic shift from invasive to non-invasive diagnostic strategynon-invasive diagnostic strategy

• Spiral CT scanSpiral CT scan• TEETEE• MRIMRI• AngiographyAngiography

ImagingImaging

• Can identify aortic dissection and other Can identify aortic dissection and other features such as:features such as:– Involvement of the ascending aortaInvolvement of the ascending aorta– Extent of dissectionExtent of dissection– Thrombus in the false lumenThrombus in the false lumen– Branch vessel or coronary artery involvementBranch vessel or coronary artery involvement– Aortic insufficiencyAortic insufficiency– Pericardial effusion with or without tamponadePericardial effusion with or without tamponade– Sites of entry and re-entrySites of entry and re-entry

AngiographyAngiography

• First definitive test for aortic dissection First definitive test for aortic dissection

• Traditionally considered “the gold standard”Traditionally considered “the gold standard”

• Involves injection of contrast media into the aortaInvolves injection of contrast media into the aorta– Identifies the site of the dissectionIdentifies the site of the dissection– Major branches of the aortaMajor branches of the aorta– Communication site between true & false lumenCommunication site between true & false lumen– Can detect thrombus in the false lumenCan detect thrombus in the false lumen

• DisadvantagesDisadvantages– Not very practical in critically ill patientsNot very practical in critically ill patients– Nephrotoxic contrastNephrotoxic contrast– Risks of an invasive procedureRisks of an invasive procedure

Spiral CTSpiral CT

• Sensitivity 83%Sensitivity 83%• Specificity 90 - 100%Specificity 90 - 100%

• Two distinct lumens with a visible intimal flap can be identifiedTwo distinct lumens with a visible intimal flap can be identified

• AdvantagesAdvantages– NoninvasiveNoninvasive– Readily available at most hospitals on an emergency basisReadily available at most hospitals on an emergency basis– Can differentiate dissection from other causes of aortic widening (tumor, Can differentiate dissection from other causes of aortic widening (tumor,

periaortic hematoma, fat)periaortic hematoma, fat)

• DisadvantagesDisadvantages– Sensitivity lower than TEE and MRISensitivity lower than TEE and MRI– Intimal flap is seen < 75% of casesIntimal flap is seen < 75% of cases– Nephrotoxic contrast is requiredNephrotoxic contrast is required– Cannot reliably detect AI, or delineate branch vesselsCannot reliably detect AI, or delineate branch vessels

TTETTE

• First used to diagnose aortic First used to diagnose aortic dissections in the ’70sdissections in the ’70s

• Sensitivity 59-85%, specificity 63-96%Sensitivity 59-85%, specificity 63-96%

• Image quality limited by obesity, lung Image quality limited by obesity, lung disease, and chest wall deformitiesdisease, and chest wall deformities

TEETEE

• Sensitivity 98% Specificity 95% Sensitivity 98% Specificity 95%

• AdvantagesAdvantages

– Close proximity of the esophagus to the thoracic aortaClose proximity of the esophagus to the thoracic aorta– Portable procedurePortable procedure– Yields diagnosis in < 5 minutesYields diagnosis in < 5 minutes– Useful in patients too unstable for MRIUseful in patients too unstable for MRI– True and false lumens can be identifiedTrue and false lumens can be identified– Thrombosis, pericardial effusion, AI, and proximal Thrombosis, pericardial effusion, AI, and proximal

coronary arteries can be readily visualizedcoronary arteries can be readily visualized

TEETEE

• Lower specificity attributed to Lower specificity attributed to reverberations atherosclerotic vessels or reverberations atherosclerotic vessels or calcified aortic disease producing echo calcified aortic disease producing echo images that resemble an aortic flapimages that resemble an aortic flap

• DisadvantagesDisadvantages– Contraindicated in patients with esophageal Contraindicated in patients with esophageal

varices, tumors, or stricturesvarices, tumors, or strictures– Potential complications: bradycardia, Potential complications: bradycardia,

hypotension, bronchospasmhypotension, bronchospasm

MRIMRI

• Most accurate noninvasive for evaluating the thoracic aortaMost accurate noninvasive for evaluating the thoracic aorta

• Sensitivity 98%Sensitivity 98%• Specificity 98%Specificity 98%

• AdvantagesAdvantages– SafeSafe– Can visualize the whole extent of the aorta in multiple planesCan visualize the whole extent of the aorta in multiple planes– Ability to assess branch vessels, AI, and pericardial effusionAbility to assess branch vessels, AI, and pericardial effusion– No contrast or radiationNo contrast or radiation

• DisadvantagesDisadvantages– Not readily available on an emergency basisNot readily available on an emergency basis– Time consumingTime consuming– Limited applicability in pts with pacemakers or metallic clipsLimited applicability in pts with pacemakers or metallic clips

ConclusionsConclusions

• Conventional TTE is of limited diagnostic value Conventional TTE is of limited diagnostic value in assessment of the thoracic aortain assessment of the thoracic aorta

• Both TEE and MRI have excellent sensitivity, Both TEE and MRI have excellent sensitivity, however MRI is more specifichowever MRI is more specific

• MRI is the study of choice for stable patientsMRI is the study of choice for stable patients

• TEE is the study of choice for unstable patientsTEE is the study of choice for unstable patients

TreatmentTreatment

• Acute dissections involving the ascending Acute dissections involving the ascending aorta are considered surgical emergenciesaorta are considered surgical emergencies

• Dissections confined to the descending Dissections confined to the descending aorta are treated medicallyaorta are treated medically

– Unless patient demonstrates continued Unless patient demonstrates continued hemorrhage into the pleural or retroperitoneal hemorrhage into the pleural or retroperitoneal spacespace

Surgical OptionsSurgical Options

• Excision of the intimal tearExcision of the intimal tear

• Obliteration of entry into the false Obliteration of entry into the false lumen proximallylumen proximally

• Reconstitution of the aorta with Reconstitution of the aorta with interposition of a synthetic vascular interposition of a synthetic vascular graftgraft

Type A DissectionsType A Dissections

• Operative mortality varies from 7-Operative mortality varies from 7-35%35%

• 27% post-op mortality27% post-op mortality– Patients who died had a higher rate of Patients who died had a higher rate of

in-hospital complications such as in-hospital complications such as strokes, renal failure, limb ischemia, & strokes, renal failure, limb ischemia, & mesenteric ischemiamesenteric ischemia

Poor prognostic factorsPoor prognostic factors

• Hypotension or shockHypotension or shock• Renal failureRenal failure• Age> 70 yrsAge> 70 yrs• Pulse deficitPulse deficit• Prior MIPrior MI• Underlying pulmonary diseaseUnderlying pulmonary disease• Preoperative neurologic impairmentPreoperative neurologic impairment• Renal and/or visceral ischemiaRenal and/or visceral ischemia• Abnormal EKG, particularly ST elevationAbnormal EKG, particularly ST elevation

Medical therapyMedical therapy

• Reduce systolic BP to 100 to 120 mmHg or the lowest level Reduce systolic BP to 100 to 120 mmHg or the lowest level that is toleratedthat is tolerated

• IV Beta blockersIV Beta blockers– Propanolol (1-10 mg load, 3mg/hr)Propanolol (1-10 mg load, 3mg/hr)– Labetalol (20 mg bolus, 0.5 to 2 mg/min)Labetalol (20 mg bolus, 0.5 to 2 mg/min)

• If SBP remains >100mmHg, nitroprusside should be addedIf SBP remains >100mmHg, nitroprusside should be added– Do not use without beta blockadeDo not use without beta blockade– Avoid hydralazineAvoid hydralazine

• Surgical intervention for Type B dissections reserved for Surgical intervention for Type B dissections reserved for patients with a complicated coursepatients with a complicated course

Long Term OutcomeLong Term Outcome

• Type AType A– Survival at 5 yrs – 68%Survival at 5 yrs – 68%– Survival at 10 yrs – 52 %Survival at 10 yrs – 52 %

• Type BType B– 5 yrs – 60 - 80%5 yrs – 60 - 80%– 10 yrs – 40 – 80%10 yrs – 40 – 80%– Spontaneous healing of dissection is Spontaneous healing of dissection is

uncommonuncommon

Long-Term ManagementLong-Term Management

• Medical therapyMedical therapy– Oral Beta-blockers (reduces aortic wall stress)Oral Beta-blockers (reduces aortic wall stress)– Keep BP < 135/80 mmHg (combination Keep BP < 135/80 mmHg (combination

therapy)therapy)– Avoidance of strenuous physical activityAvoidance of strenuous physical activity

• Serial imagingSerial imaging– Thoracic MR scan prior to dischargeThoracic MR scan prior to discharge– f/u scans at 3, 6, and 12 monthsf/u scans at 3, 6, and 12 months– Subsequent screening studies done every 1-2 Subsequent screening studies done every 1-2

yrs if no evidence of progressionyrs if no evidence of progression