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Aortic Dissection Jason S. Finkelstein, M.D. Cardiology Fellow Tulane University 8/11/03.

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Presentation on theme: "Aortic Dissection Jason S. Finkelstein, M.D. Cardiology Fellow Tulane University 8/11/03."— Presentation transcript:

1 Aortic Dissection Jason S. Finkelstein, M.D. Cardiology Fellow Tulane University 8/11/03

2 Overview Incidence of aortic dissection is at least 2000 new cases per year Incidence of aortic dissection is at least 2000 new cases per year Peak incidence is in the sixth to seventh decade Peak incidence is in the sixth to seventh decade Men are affected twice as commonly as women Men are affected twice as commonly as women Mortality in the first 48 hours is 1% per hour Mortality in the first 48 hours is 1% per hour –Early diagnosis is essential

3 Pathophysiology The chief predisposing factor is degeneration of collagen and elastin in the aortic intima media The chief predisposing factor is degeneration of collagen and elastin in the aortic intima media Blood passes through the tear into the aortic media, separating the media from the intima and creating a false lumen Blood passes through the tear into the aortic media, separating the media from the intima and creating a false lumen Dissection can occur both distal and proximal to the tear Dissection can occur both distal and proximal to the tear

4 Classification Debakey system Debakey system –Type I Originates in the ascending aorta, propagates to the aortic arch and beyond it distally Originates in the ascending aorta, propagates to the aortic arch and beyond it distally –Type II Confined to the ascending aorta Confined to the ascending aorta –Type III Confined to the descending aorta, and extends distally, or rarely retrograde into the aortic arch Confined to the descending aorta, and extends distally, or rarely retrograde into the aortic arch

5 Classification The Stanford system The Stanford system –Type A All dissections involving the ascending aorta All dissections involving the ascending aorta –Type B All other dissections regardless of the site of the primary intimal tear All other dissections regardless of the site of the primary intimal tear –Ascending aortic dissections are twice as common as descending

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7 Predisposing factors Age, yrs old Age, yrs old Long standing history of hypertension Long standing history of hypertension –80% of cases have co-existing HTN Takayasu’s arteritis Takayasu’s arteritis Giant cell arteritis Giant cell arteritis Syphilis Syphilis Collagen disorders Collagen disorders –Marfan syndrome (6-9% of aortic dissections) –Ehlers-Danlos syndrome

8 Other Risk Factors Congenital Cardiac Anomalies Congenital Cardiac Anomalies –Bicuspid aortic valve (7-14% of cases) –Coarctation of the aorta Cocaine Cocaine –Abrupt HTN, due to catecholamine release Trauma Trauma 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 replacement) Iatrogenic (cardiac cath, IABP, cardiac surgery, s/p valve replacement)

9 Clinical Symptoms Severe, sharp, “tearing” posterior chest pain or back pain (occurs in 74-90% of pts) Severe, sharp, “tearing” posterior chest pain or back pain (occurs in 74-90% of pts) –Pain may be associated with syncope, CVA, MI, or CHF –Painless dissection relatively uncommon Chest pain is more common with Type A dissections Chest pain is more common with Type A dissections Back or abdominal pain is more common with Type B dissections Back or abdominal pain is more common with Type B dissections

10 Physical Exam Pulse deficit Pulse deficit –Weak or absent carotid, brachial, or femoral pulses –these patients have a higher rate of mortality Acute Aortic Insufficiency Acute Aortic Insufficiency –Diastolic decrescendo murmur –Best heard along the right sternal border

11 Clinical signs Acute MI Acute MI –RCA most commonly involved Cardiac tamponade Cardiac tamponade Pleural effusions Pleural effusions Hypertension or hypotension Hypertension or hypotension Hemothorax Hemothorax Variation in BP between the arms (>30mmHg) Variation in BP between the arms (>30mmHg) Neurologic deficits Neurologic deficits –Stroke or decreased consciousness

12 Clinical Signs Involvement of the descending aorta Involvement of the descending aorta –Splanchnic ischemia –Renal insufficiency –Lower extremity ischemia –Spinal cord ischemia

13 Diagnosis Generally suspected from the history and PE Generally suspected from the history and PE In a recent study in 2000, 96% of acute dissection patients could be identified based upon a combination of three clinical features In a recent study in 2000, 96% of acute dissection patients could be identified based upon a combination of three clinical features –Immediate onset of chest pain –Mediastinal widening on CXR –A variation in pulse and/or blood pressure (>20 mmHg difference between R & L arm Incidence >83% when any combination of all three variables occurred Incidence >83% when any combination of all three variables occurred

14 Differential Diagnosis Acute Coronary Syndrome Acute Coronary Syndrome Pericarditis Pericarditis Pulmonary embolus Pulmonary embolus Pleuritis Pleuritis Cholecystitis Cholecystitis Perforating ulcer Perforating ulcer

15 Diagnostic Tests EKG EKG –Absence of EKG changes usually helps distinguish dissection from angina –Usually non-specific ST-T wave changes seen CXR CXR Cardiac Enzymes Cardiac Enzymes

16 Chest X-Ray May show widening of the aorta with ascending aorta dissections May show widening of the aorta with ascending aorta dissections –Present in 63 % of patients with Type A dissections

17 Diagnostic Imaging Not performed until the patient is medically stable Not performed until the patient is medically stable Has been a dramatic shift from invasive to non- invasive diagnostic strategy Has been a dramatic shift from invasive to non- invasive diagnostic strategy Spiral CT scan Spiral CT scan TEE TEE MRI MRI Angiography Angiography

18 Imaging Can identify aortic dissection and other features such as: Can identify aortic dissection and other features such as: –Involvement of the ascending aorta –Extent of dissection –Thrombus in the false lumen –Branch vessel or coronary artery involvement –Aortic insufficiency –Pericardial effusion with or without tamponade –Sites of entry and re-entry

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20 Angiography 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 aorta Involves injection of contrast media into the aorta –Identifies the site of the dissection –Major branches of the aorta –Communication site between true & false lumen –Can detect thrombus in the false lumen Disadvantages Disadvantages –Not very practical in critically ill patients –Nephrotoxic contrast –Risks of an invasive procedure

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22 Spiral CT Sensitivity 83% Sensitivity 83% Specificity % Specificity % Two distinct lumens with a visible intimal flap can be identified Two distinct lumens with a visible intimal flap can be identified Advantages Advantages –Noninvasive –Readily available at most hospitals on an emergency basis –Can differentiate dissection from other causes of aortic widening (tumor, periaortic hematoma, fat) Disadvantages Disadvantages –Sensitivity lower than TEE and MRI –Intimal flap is seen < 75% of cases –Nephrotoxic contrast is required –Cannot reliably detect AI, or delineate branch vessels

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26 TTE First used to diagnose aortic dissections in the ’70s First used to diagnose aortic dissections in the ’70s Sensitivity 59-85%, specificity 63-96% Sensitivity 59-85%, specificity 63-96% Image quality limited by obesity, lung disease, and chest wall deformities Image quality limited by obesity, lung disease, and chest wall deformities

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28 TEE Sensitivity 98% Specificity 95% Sensitivity 98% Specificity 95% Advantages Advantages –Close proximity of the esophagus to the thoracic aorta –Portable procedure –Yields diagnosis in < 5 minutes –Useful in patients too unstable for MRI –True and false lumens can be identified –Thrombosis, pericardial effusion, AI, and proximal coronary arteries can be readily visualized

29 TEE Lower specificity attributed to reverberations atherosclerotic vessels or calcified aortic disease producing echo images that resemble an aortic flap Lower specificity attributed to reverberations atherosclerotic vessels or calcified aortic disease producing echo images that resemble an aortic flap Disadvantages Disadvantages –Contraindicated in patients with esophageal varices, tumors, or strictures –Potential complications: bradycardia, hypotension, bronchospasm

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32 MRI Most accurate noninvasive for evaluating the thoracic aorta Most accurate noninvasive for evaluating the thoracic aorta Sensitivity 98% Sensitivity 98% Specificity 98% Specificity 98% Advantages Advantages –Safe –Can visualize the whole extent of the aorta in multiple planes –Ability to assess branch vessels, AI, and pericardial effusion –No contrast or radiation Disadvantages Disadvantages –Not readily available on an emergency basis –Time consuming –Limited applicability in pts with pacemakers or metallic clips

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34 Conclusions Conventional TTE is of limited diagnostic value in assessment of the thoracic aorta Conventional TTE is of limited diagnostic value in assessment of the thoracic aorta Both TEE and MRI have excellent sensitivity, however MRI is more specific Both TEE and MRI have excellent sensitivity, however MRI is more specific MRI is the study of choice for stable patients MRI is the study of choice for stable patients TEE is the study of choice for unstable patients TEE is the study of choice for unstable patients

35 Treatment Acute dissections involving the ascending aorta are considered surgical emergencies Acute dissections involving the ascending aorta are considered surgical emergencies Dissections confined to the descending aorta are treated medically Dissections confined to the descending aorta are treated medically –Unless patient demonstrates continued hemorrhage into the pleural or retroperitoneal space

36 Surgical Options Excision of the intimal tear Excision of the intimal tear Obliteration of entry into the false lumen proximally Obliteration of entry into the false lumen proximally Reconstitution of the aorta with interposition of a synthetic vascular graft Reconstitution of the aorta with interposition of a synthetic vascular graft

37 Type A Dissections Operative mortality varies from 7-35% Operative mortality varies from 7-35% 27% post-op mortality 27% post-op mortality –Patients who died had a higher rate of in- hospital complications such as strokes, renal failure, limb ischemia, & mesenteric ischemia

38 Poor prognostic factors Hypotension or shock Hypotension or shock Renal failure Renal failure Age> 70 yrs Age> 70 yrs Pulse deficit Pulse deficit Prior MI Prior MI Underlying pulmonary disease Underlying pulmonary disease Preoperative neurologic impairment Preoperative neurologic impairment Renal and/or visceral ischemia Renal and/or visceral ischemia Abnormal EKG, particularly ST elevation Abnormal EKG, particularly ST elevation

39 Medical therapy Reduce systolic BP to 100 to 120 mmHg or the lowest level that is tolerated Reduce systolic BP to 100 to 120 mmHg or the lowest level that is tolerated IV Beta blockers IV Beta blockers –Propanolol (1-10 mg load, 3mg/hr) –Labetalol (20 mg bolus, 0.5 to 2 mg/min) If SBP remains >100mmHg, nitroprusside should be added If SBP remains >100mmHg, nitroprusside should be added –Do not use without beta blockade –Avoid hydralazine Surgical intervention for Type B dissections reserved for patients with a complicated course Surgical intervention for Type B dissections reserved for patients with a complicated course

40 Long Term Outcome Type A Type A –Survival at 5 yrs – 68% –Survival at 10 yrs – 52 % Type B Type B –5 yrs – % –10 yrs – 40 – 80% –Spontaneous healing of dissection is uncommon

41 Long-Term Management Medical therapy Medical therapy –Oral Beta-blockers (reduces aortic wall stress) –Keep BP < 135/80 mmHg (combination therapy) –Avoidance of strenuous physical activity Serial imaging Serial imaging –Thoracic MR scan prior to discharge –f/u scans at 3, 6, and 12 months –Subsequent screening studies done every 1-2 yrs if no evidence of progression


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