Aortic dissection resident survival guide: Difference between revisions
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== | ==Overview== | ||
A tear in the layers of the aorta especially in the intima leading to bleeding and separation of the layers of the aorta from within which creates a false lumen. | A tear in the layers of the aorta especially in the intima leading to bleeding and separation of the layers of the aorta from within which creates a false lumen. | ||
Aortic dissection can be further defined as: | Aortic dissection can be further defined as: |
Revision as of 16:29, 11 March 2014
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Chetan Lokhande, M.B.B.S [2]
Overview
A tear in the layers of the aorta especially in the intima leading to bleeding and separation of the layers of the aorta from within which creates a false lumen. Aortic dissection can be further defined as:
- Acute aortic dissection- Dissection occurring within 2 weeks of onset of pain
- Subacute aortic dissection-Dissection occurring witin 2-6 weeks of onset of pain
- Chronic aortic dissection- Dissection occurring within 6 weeks of pain.
Classification
Aortic dissection can be classified into four types. DeBakey and Daily (Stanford) systems are the commonly used systems used to classify aortic dissection.[1][2][3][4]
- Stanford system classifies dissection into the following two types based on whether ascending aorta is involved or not.
- Ascending aortic dissection or type A
- All other dissections or type B
- DeBakey system classifies dissection according to location of the tear.
- Type I- Starts at ascending aorta and extension upto the aortic arch
- Type II- Starts and is limited till the ascending aorta
- Type III- Starts in the descending aorta and progresses proximally or distally
- Type III A - Restricted till the descending thoracic aorta
- Type III B - Dissection extending below the diaphragm
- The third type of classification divides aortic dissection according to the proximity
- Proximal- Ascending aortic involvement
- Distal- Descending aortic involvement distal to left subclavian artery
Causes
Life Threatening Causes
Aortic dissection is a life-threatening condition and must be treated as such irrespective of the causes. Life-threatening conditions may result in death or permanent disability within 24 hours if left untreated.
Common Causes
- Atherosclerosis
- Complication of cardiac procedures
- Chest trauma
- Connective tissue disorders
- Hypertension
- Vasculitis[5]
Management
Obtain a detailed history:
❑ Past medical history
❑ Family history
- ❑ Aortic disorder*
- ❑ Connective tissue disorder*
❑ Anatomic deformities
- ❑ Aortic valve disease*
- ❑ Thoracic aortic aneurysm*
- ❑ Coarctation of aorta
- ❑ Polycystic kidney disease
❑ Iatrogenic
- ❑ Recent aortic manipulation*
- ❑ Chronic steroid usage
- ❑ Immunosuppressive therapy
❑ Lifestyle
- ❑ Cocaine abuse
- ❑ Heavy weight lifting
❑ Trauma
❑ Genetic
- ❑ Marfan's syndrome*
- ❑ Ehlers-Danlos syndrome
- ❑ Turners syndrome
- ❑ Biscuspid aortic valve
- ❑ Loeys-Dietz syndrome
- ❑ Familial thoracic aneurysm and dissection syndrome
❑ Inflammatory vasculitis
❑ Pregnancy
❑ Infections involving the aorta }} {{familytree | | | | | | | | B01 | | | |B01=❑ General examination:
- ❑ Pulse rate - ↑
- ❑ Blood pressure - ↑ or ↓
- ❑ Respiratory rate - ↑
- ❑ Wide pulse pressure
- ❑ Difference in the blood pressure in both extremities*
- ❑ Increased sweating or anhidrosis
- ❑ Signs of shock (hypoperfusion)*
- ❑ Pulse deficit involving carotid, femoral or subclavian arteries*
❑ Head/neck examination:
- ❑ ↑ JVP
- ❑ Signs of vocal cord paralysis
- ❑ Pemberton's sign (SVC)
- ❑ Venous distention in the neck and distended veins in the upper chest and arms (SVC)
❑ Cardiovascular examination:
- ❑ Diastolic murmur suggestive of aortic regurgitation*
- ❑ Wheeze (cardiac asthma) (CHF)
- ❑ Pericardial friction rub
❑ Respiratory examination
- ❑ Crackles / crepitations / rales
- ❑ Decreased movement of the chest on affected side
- ❑ Stony dullness to percussion
- ❑ Diminished breaths sounds
- ❑ Decreased vocal resonance and fremitus
- ❑ Pleural friction rub.
❑ Abdominal examination:
- ❑ Ascites
- ❑ Claudication of buttocks
- ❑ Absent femoral pulses
❑ Neurological examination:
- ❑ Altered mental status*
- ❑ Signs of peripheral neuropathy
- ❑ Signs of stroke*
❑ Extremity examination:
- ❑ Pedal edema
❑ Ophthalmological examination
❑ Assess the severity by counting the high risk features marked in bold and by *
❑ Consider close differential diagnoses:
- ❑ Myocardial infarction due to an acute coronary syndrome with or without ST segment elevation
- ❑ Aortic regurgitation without dissection
- ❑ Aortic aneurysm without dissection
- ❑ Pericarditis
- ❑ Atherosclerotic or cholesterol embolism
- ❑ Pulmonary embolus
- ❑ Pleuritis
- ❑ Cholecystitis
- ❑ Peptic ulcer disease or perforating ulcer
- ❑ Acute pancreatitis
- ❑ Esophageal perforation rupture
- ❑ Musculoskeletal pain
- ❑ Mediastinal tumors
Characterize the symptoms: ❑ Cardiac
❑ Extra cardiac
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Do's
History and Examination
- For pre-test risk determination include information about:
- Medical History
- Family history and ask specifically for family history of aortic dissection or thoracic aneurysm
- Pain history
- Do a detailed physical examination to identify findings for certain high risk conditions like:(class I, level of evidence B)
- Marfans'syndrome
- Loey's-Dietz syndrome
- Ehler's Danlos syndrome
- Turner's syndrome
- Connective tissue disorder
- Check for genetic mutations predisposing to dissection:(class I, level of evidence B)
- FBN1
- TGFBR1
- TGFBR2
- ACTA2
- MYHH11
- Any recent aortic or surgical or catheter manipulation.(class I, level of evidence C)
- Ask in detail about the pain. Include the following:(class I, level of evidence B)
- Onset of pain whether abrupt or instantaneous
- Severity of pain
- Quality of pain whether ripping, tearing,stabbing or sharp.
- Check for the following features on examination:(class I, level of evidence B)
- Pulse deficits
- Blood pressure (systolic) difference of above 20 mm of hg in limbs
- New aortic regurgitation features
- Focal neurological deficit
- Patients less than 40 years of age and presenting with sudden chest, abdominal or back pain should be evaluated for high risk conditions.
- Patients presenting with features of syncope along with features of dissection should have a detailed neurological examination and cardiovascular examination to rule out pericardial tamponade and other neurological deficits.(class I, level of evidence C)
Screening Tests
- Do an EKG on all patients with dissection symptoms.(class I, level of evidence B)
- If ST elevation is present in EKG then treat the patient as an acute cardiac event unless the patient has high risk factors for acute dissection.
- If EKG shows ST elevation with no dissection features then perform a coronary angiography and then do a thrombolysis or percutaneous coronary intervention.
- Do a X-ray for all patients with intermediate risk and low risk to rule out alternate diagnosis.(class I, level of evidence C)
- High risk patients should be evaluated by transesophageal echocardiogram, computed tomography or magnetic resonance imaging to rule out dissection.(class I, level of evidence B)
Initial Management
- Medical management should be aimed at decreasing aortic wall stress. (class I, level of evidence C)
- Titrate Beta blocker to maintain heart rate of 60 beats/ minute. class I, level of evidence C
- If beta blockers are contra indicated then use nondihyropyridine calcium channel blockers to control rate. class I, level of evidence C
- If BP remains above 120 mm of hg even after medical treatment then use angiotensin converting enzyme and other vasodilators to maintain end organ perfusion.class I, level of evidence C
Definitive Management
- Do a surgical consultation for all patients once diagnosed with aortic dissection. This applies to patients presenting with dissection at any location. class I, level of evidence C
- Do an emergent repair in acute dissection of ascending aorta to prevent complications like rupture. class I, level of evidence C
- Treat all descending aorta medically unless complicated by life threatening conditions like perfusion deficit, dissection enlargement, aneurysmal enlargement or blood pressure refractory to treatment. class I, level of evidence C
- Do a definitive aortic imaging study as soon as Chest X-ray suggests widened mediastinum.
- Goal should be to maintain heart rate less than 60 beats / minute and blood pressure between 100 and 120 mm hg.
- Use Esmolol if asthma, congestive heart failure or chronic obstructive pulmonary disease.
- Use Labetalol to maintain heart rate and blood pressure, it prevents usage of another vasodilator.
- Do pericardiocentes for pericardial bleeding and dissection related hemopericardium.
- Do a plasma smooth muscle myosin heavy chain protein, D-dimer and high sensitive C-reactive protein to rule out alternate diagnosis.
Dont's
- Don't use beta blocker in patients having aortic regurgitation as they may block the tachycardia caused by compensation.
- Don't use vasodilator before heart rate is controlled otherwise there would be reflex tachycardia which would increase the stress on aorta and worsening the dissection.
- Use Sodium nitroprusside as the first line for treating hypertension. Nicardipine, nitroglycerin and fenoldopam are other drugs used to treat hypertension.
References
- ↑ Nienaber, CA.; Eagle, KA. (2003). "Aortic dissection: new frontiers in diagnosis and management: Part I: from etiology to diagnostic strategies". Circulation. 108 (5): 628–35. doi:10.1161/01.CIR.0000087009.16755.E4. PMID 12900496. Unknown parameter
|month=
ignored (help) - ↑ Tsai, TT.; Nienaber, CA.; Eagle, KA. (2005). "Acute aortic syndromes". Circulation. 112 (24): 3802–13. doi:10.1161/CIRCULATIONAHA.105.534198. PMID 16344407. Unknown parameter
|month=
ignored (help) - ↑ DEBAKEY, ME.; HENLY, WS.; COOLEY, DA.; MORRIS, GC.; CRAWFORD, ES.; BEALL, AC. (1965). "SURGICAL MANAGEMENT OF DISSECTING ANEURYSMS OF THE AORTA". J Thorac Cardiovasc Surg. 49: 130–49. PMID 14261867. Unknown parameter
|month=
ignored (help) - ↑ Daily, PO.; Trueblood, HW.; Stinson, EB.; Wuerflein, RD.; Shumway, NE. (1970). "Management of acute aortic dissections". Ann Thorac Surg. 10 (3): 237–47. PMID 5458238. Unknown parameter
|month=
ignored (help) - ↑ "Classification of diabetic retinopathy from fluorescein angiograms. ETDRS report number 11. Early Treatment Diabetic Retinopathy Study Research Group". Ophthalmology. 98 (5 Suppl): 807–22. 1991. PMID 2062514.