Dissection, Aortic

• Chest x-ray (CXR): This study is abnormal in 80% of patients and is more commonly abnormal in ascending aortic dissections (see Picture 1).

• Findings suggesting hemothorax may be found if the dissection ruptures into the pleura (see Picture 2).

• Widened mediastinum: Radiographic findings in acute thoracic dissection include a widened mediastinum in many cases (see Picture 3).
  • Recently, the International Registry of Acute Aortic Dissection published data on 464 patients that showed only 25% presenting with this finding.

  • A widened mediastinum is sometimes difficult to identify on a portable anteroposterior (AP) CXR. If the patient is hemodynamically stable and cooperative, an AP film can be obtained at bedside.

  • Look for a mediastinal width >8 cm on AP CXR.

  • A tortuous aorta, common in hypertensive patients, may be hard to distinguish from a widened mediastinum. If in doubt, a good posterior-anterior CXR is recommended.

  • The differential diagnosis of a widened mediastinum includes tumor, adenopathy, lymphoma, and enlarged thyroid.

• Abnormal (ie, blunted) aortic knob was observed in 66% of patients in one study.

• Ring sign (displacement of the aorta >5 mm past the calcified aortic intima) is considered a very specific radiographic sign.

• Other radiologic abnormalities seen on CXR include the following:
  • Left apical cap

  • Tracheal deviation

  • Depression of left main stem bronchus

  • Esophageal deviation

  • Loss of the paratracheal stripe

• One study concluded that it was not any one sign that determined the overall diagnosis, rather a combination of all findings that led to suspicion of dissection.

• Angiography: Still considered by some as the criterion standard test for aortic dissection, it is being replaced by newer imaging modalities.

• Angiography accurately diagnoses aortic dissection in over 95% of patients (see Picture 4) and aids the surgeon in planning the repair operation, as blood vessels of the arch can be assessed easily. Benefits include visualization of the true and false lumens, intimal flap, aortic regurgitation, and coronary arteries.

• Drawbacks include the following:
  • The procedure is invasive.

  • The patient must be transported to the radiology department, leaving the ED.

  • The use of contrast media may be harmful to patients who have renal insufficiency or an allergy to iodine.

  • Misdiagnoses can occur if the false channel is thrombosed. In this instance, the false lumen and intimal flap may not be visualized. Possible simultaneous opacification of the true and false lumens may make it difficult to discern whether a dissection is present.

• Computed tomography (CT): With the advent of helical CT with multiplanar and 3D reconstruction, CT is quickly replacing the angiogram as the criterion standard in many institutions.

• Prospective studies have shown a sensitivity of 83-94% with a specificity of 87-100%.

• Spiral CT is associated with a higher rate of detection and better resolution than incremental CT. High-quality 2D and 3D reconstructions are possible with spiral CT, which greatly adds to the usefulness of this imaging modality.

• More importantly, imaging information, including the type of lesion, location of the pathologic lesion, and extent of the disease, can be assessed quickly and help the surgeon plan the operation.

• This information helps determine if hypothermic circulatory arrest is necessary for surgery; this procedure increases the complexity, length, morbidity, and mortality associated with surgery.

• Helical CT images usually are acquired within 1-2 breath holds.

• Drawbacks include the following:
  • Transportation of a patient in potentially unstable condition from the ED, even for the relatively short time needed for this procedure, places the patient at risk.

  • The use of contrast material may harm a patient who has impaired renal function or an allergy to contrast media.

  • CT scan provides no information on aortic regurgitation.

• Echocardiography

• With its increasing acceptance and use in the ED, ultrasound is becoming a very valuable diagnostic aid, although transthoracic echocardiography (TTE) has a much lower sensitivity (80%) and lower specificity (90%) than angiography.

• TTE is most useful in ascending aortic dissections, especially those closest to the aortic root and within a few centimeters of the aortic valve. Sensitivity is highest in this location.

• ECG also is useful in diagnosing cardiac tamponade and aortic regurgitation.

• Benefits include its rapid, simple bedside use in the ED and its noninvasive nature.

• Drawbacks include the lack of sensitivity and specificity, especially with arch and descending aortic dissections, and dependence on operator experience.

• Transesophageal echocardiography (TEE) has greater sensitivity and specificity than transthoracic echocardiography (in the range of 97-99% and 97-100%, respectively).
  • Advantages include its quick and easy bedside use in the ED, which makes it ideal for patients in unstable condition.

  • TEE detects involvement of the coronary arteries, aortic insufficiency, and cardiac tamponade.

  • It is a relatively quick study to perform and relatively noninvasive.

  • The main drawback of TEE is its strong dependence on operator experience.

  • Other drawbacks are that false positives can occur from reverberations in the ascending aorta and that the upper ascending aorta and arch may not be visualized well, leading to false negatives.

  • TEE cannot be performed in patients with esophageal varicosities or stenosis. If the study is negative and clinical suspicion remains high, a second diagnostic test is recommended.

• Magnetic resonance imaging (MRI)

• MRI has over 90% sensitivity and greater than 95% specificity. MRI shows the site of intimal tear, type and extent of dissection, and presence of aortic insufficiency.

• Other benefits are that MRI requires no contrast medium and no ionizing radiation.

• Drawbacks include the following:
  • MRI is not readily available at most institutions, requiring transportation of patients in unstable condition away from the ED.

  • MRI requires much more time to acquire images than CT.

  • Patients with permanent pacemakers cannot undergo MRI. Most patients with prosthetic heart valves or coronary stents can safely have an MRI.

Other Tests:

• ECG: All patients with suspected thoracic aortic dissection should have an ECG.

• In acute thoracic dissection, ECG can mimic the changes seen in acute cardiac ischemia. In the presence of chest pain, these signs can make distinguishing dissection from AMI very difficult (see Picture 5). Keep this in mind when administering thrombolytics to patients with chest pain.

• ST elevation can be seen in Stanford type A dissections, as the dissection interrupts blood flow to the coronary arteries.
  • The incidence of abnormal ECG findings is greater in Stanford type A dissections than in other types of dissections.

  • In one study, 8% of patients with type A dissections had ST elevation, while no patients with type B dissections had ST elevation.

  • More commonly, the ECG abnormality is ST depression.

TREATMENT

Section 6 of 11

Prehospital Care:

• Assure adequate breathing, maintain oxygenation, treat shock, and obtain useful historic information.

• Establishing the diagnosis in the field is usually difficult or impossible, but certain salient features of aortic dissection may be observed. It is life threatening if not quickly recognized and treated.

• Radio communication with the receiving hospital permits the medical control physician to direct care and select a capable destination hospital while permitting the ED to mobilize appropriate resources.

• In the rare event that the diagnosis can be made based on prehospital information, the physician directing prehospital care should request transport to a facility capable of operative treatment of an aortic dissection.

Emergency Department Care:

• The mortality rate of patients with aortic dissection is 1-2% per hour for the first 24-48 hours. Initial therapy should begin when the diagnosis is suspected. This includes 2 large-bore intravenous lines (IVs), oxygen, respiratory monitoring, and monitoring of cardiac rhythm, blood pressure, and urine output.

• Clinically, the physician should reassess the patient frequently for hemodynamic compromise, mental status changes, neurologic or peripheral vascular changes, and development or progression of carotid, brachial, and femoral bruits.

• Urgent surgical intervention is required in type A dissections.

• The area of the aorta with the intimal tear usually is resected and replaced with a Dacron graft.

• The operative mortality rate is usually less than 10% and serious complications are rare with ascending aortic dissections.

• The development of more impermeable grafts, such as woven Dacron, collagen-impregnated Hemashield (Meadox Medicals, Oakland, NJ), aortic grafts, and gel-coated Carbo-Seal Ascending Aortic Prothesis (Sulzer Carbomedics, Austin, TX) has greatly enhanced the surgical repair of thoracic aortic dissections.

• With the introduction of profound hypothermic circulatory arrest and retrograde cerebral perfusion, the morbidity and mortality rates associated with this highly invasive surgery have decreased.

• Dissections involving the arch are more complicated that those involving only the ascending aorta, as the innominate, carotid, and subclavian vessels branch from the arch. Deep hypothermic arrest usually is required. If the arrest time is less than 45 minutes, the incidence of central nervous system complications is less than 10%.

• Retrograde cerebral perfusion may increase the protection of the central nervous system during the arrest period.

• Mortality rate of aortic arch dissections is about 10-15%, with significant neurologic complications occurring in another 10%.

• The mortality rate is influenced by the patient's clinical condition.

• The definitive treatment for type B dissections is less clear.

• Uncomplicated distal dissections may be treated medically to control blood pressure.

• Distal dissections treated medically have the same or lower mortality rate as those treated surgically.

• Surgery is reserved for distal dissections that are leaking, ruptured, or compromising blood flow to a vital organ.

• Acute distal dissections in patients with Marfan syndrome usually are treated surgically.

• Inability to control hypertension with medication is also an indication for surgery in those with a distal thoracic aortic dissection.

• Patients with a distal dissection are usually hypertensive, emphysematous, or older.

• Long-term medical therapy involves a beta-adrenergic blocker combined with other antihypertensive medications. Avoid antihypertensives (eg, hydralazine, minoxidil) that produce a hyperdynamic response that would increase dP/dT (ie, alter the duration of P or T waves).

• Survivors of surgical therapy also should receive beta-adrenergic blockers.

• Definitive treatment involves segmental resection of the dissection with interposition of a synthetic graft.

• When thoracic dissections are associated with aortic valvular disease, replace the defective valve.

• With combined reconstruction-valve replacement, the operative mortality rate is approximately 5% with a late mortality rate of less than 10%.

• Operative repair of the transverse aortic arch is technically difficult, with an operative mortality rate of 10% despite induction of hypothermic cardiocirculatory arrest.

• Repair of the descending aorta is associated with a higher incidence of paraplegia than repair of other types of dissections because of interruption of segmental blood supply to the spinal cord.

• Operative mortality rate is approximately 5%.

Consultations:

• Once a thoracic dissection is suspected, consult a thoracic surgeon.

• Since many patients with this disorder have concomitant medical illness, consult the patient's primary care physician to expedite preoperative preparation.

• Early consultation is encouraged when ordering further imaging studies if the patient requires rapid operative intervention.

• Consult a radiologist prior to obtaining aortography.

MEDICATION

Section 7 of 11

Initial therapeutic goals include elimination of pain and reduction of systolic blood pressure to 100-120 mm Hg, or to the lowest level commensurate with adequate vital organ (cardiac, cerebral, renal) perfusion.

Whether systolic hypertension or pain is present, beta-blockers are used to reduce arterial dP/dt.

To prevent exacerbations of tachycardia and hypertension, treat patient with IV morphine sulfate. This reduces the force of cardiac contraction and the rate of rise of the aortic pressure (dP/dT). It then retards the propagation of the dissection and delays rupture.

Drug Category: Antihypertensives -- These agents are used to reduce arterial dP/dt. For acute reduction of arterial pressure, the potent vasodilator sodium nitroprusside is very effective. To reduce dP/dt acutely, administer an IV beta-blocker in incremental doses until a heart rate of 60-80 beats/min is attained.
When beta-blockers are contraindicated, such as in second- or third-degree atrioventricular block, consider using calcium channel blockers. Sublingual nifedipine successfully treats refractory hypertension associated with aortic dissection.

Drug Name	Esmolol (Brevibloc) -- Ultra-short-acting beta 2-blocker, particularly useful in patients with labile arterial pressure, especially if surgery is planned, because it can be discontinued abruptly if necessary. Normally used in conjunction with nitroprusside. May be useful as a means to test beta-blocker safety and tolerance in patients with history of obstructive pulmonary disease who are at uncertain risk of bronchospasm from beta-blockade. Elimination half-life is 9 min.
Adult Dose	Loading dose infusion: 250-500 mcg/kg/min for 1 min, followed by a 4-min maintenance infusion of 50 mcg/kg/min; repeat loading dose and follow with maintenance infusion using increments of 50 mcg/kg/min (for 4 min) if therapeutic effects not observed in 5 min; repeat sequence up to 4 times prn As desired BP is approached, omit loading infusion and reduce incremental dose in maintenance infusion from 50 mcg/kg/min to 25 mcg/kg/min or lower; may increase interval between titration steps from 5-10 min if desired
Pediatric Dose	Not established
Contraindications	Documented hypersensitivity; uncompensated CHF, bradycardia, cardiogenic shock, AV conduction abnormalities
Interactions	Aluminum salts, barbiturates, NSAIDs, penicillins, calcium salts, cholestyramine, and rifampin may decrease bioavailability and plasma levels, possibly resulting in decreased pharmacologic effect; sparfloxacin, astemizole (recalled from US market), calcium channel blockers, quinidine, flecainide, and contraceptives may increase cardiotoxicity; digoxin, flecainide, acetaminophen, clonidine, epinephrine, nifedipine, prazosin, haloperidol, phenothiazines, and catecholamine-depleting agents may increase toxicity
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Beta-adrenergic blockers may mask signs and symptoms of acute hypoglycemia and clinical signs of hyperthyroidism; symptoms of hyperthyroidism, including thyroid storm, may worsen when medication is withdrawn abruptly; withdraw drug slowly and monitor patient closely

Drug Name	Labetalol (Normodyne, Trandate) -- Blocks alpha-, beta 1-, and beta 2-adrenergic receptor sites, decreasing BP.
Adult Dose	Initial dose: 20 mg (0.25 mg/kg for 80-kg patient) IV over 2 min; follow with 20-80 mg q10-15min until BP controlled Maintenance dose: 2 mg/min continuous infusion; titrate up to 5-20 mg/min; not to exceed a total dose of 300 mg
Pediatric Dose	Not established
Contraindications	Documented hypersensitivity; cardiogenic shock, AV block, uncompensated CHF, pulmonary edema, bradycardia; reactive airway disease
Interactions	Decreases effects of diuretics and increases toxicity of methotrexate, lithium, and salicylates; may diminish reflex tachycardia associated with nitroglycerin use without interfering with hypotensive effects; cimetidine may increase blood levels; glutethimide may decrease effects by inducing microsomal enzymes
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Caution in impaired hepatic function; discontinue therapy if signs of liver dysfunction; in elderly patients, lower response rate and higher incidence of toxicity may be observed

Drug Name	Propranolol (Inderal, Betachron E-R) -- Class II antiarrhythmic nonselective beta-adrenergic receptor blocker. Has membrane-stabilizing activity and decreases automaticity of contractions. Not suitable for emergency treatment of hypertension. Do not administer IV in hypertensive emergencies.
Adult Dose	40-80 mg PO bid initially; increase to usual range of 160-320 mg/d prn; up to 640 mg/d may be required
Pediatric Dose	0.5 mg/kg/d PO divided bid/qid; increase gradually q3-7d; usual dosage range is 2-4 mg/kg/d divided bid; not to exceed 16 mg/kg/d
Contraindications	Documented hypersensitivity; uncompensated CHF, bradycardia, cardiogenic shock, and AV conduction abnormalities
Interactions	Aluminum salts, barbiturates, NSAIDs, penicillins, calcium salts, cholestyramine, and rifampin may decrease effects; calcium channel blockers, cimetidine, loop diuretics, and MAOIs may increase toxicity; may increase toxicity of hydralazine, haloperidol, benzodiazepines, and phenothiazines
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Beta-adrenergic blockade may decrease signs of acute hypoglycemia and hyperthyroidism; abrupt withdrawal may exacerbate symptoms of hyperthyroidism, including thyroid storm; withdraw drug slowly and monitor closely

Drug Name	Metoprolol (Lopressor) -- Selective beta 1-adrenergic receptor blocker that decreases automaticity of contractions. During IV administration, carefully monitor BP, heart rate, and ECG. When considering conversion from IV to PO dosage forms, use ratio of 2.5 mg PO to 1 mg IV metoprolol.
Adult Dose	100 mg/d qd or divided bid/tid initially; increase at 1-wk intervals prn; not to exceed 450 mg/d prn
Pediatric Dose	Not established
Contraindications	Documented hypersensitivity; uncompensated CHF, cardiogenic shock, bradycardia, and AV conduction abnormalities
Interactions	Aluminum salts, barbiturates, NSAIDs, penicillins, calcium salts, cholestyramine, and rifampin may decrease bioavailability and plasma levels, possibly resulting in decreased pharmacologic effects; sparfloxacin, phenothiazines, astemizole (recalled from US market), calcium channel blockers, quinidine, flecainide, and contraceptives may increase toxicity; may increase toxicity of digoxin, flecainide, clonidine, epinephrine, nifedipine, prazosin, verapamil, and lidocaine
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Beta-adrenergic blockade may reduce signs and symptoms of acute hypoglycemia and may decrease clinical signs of hyperthyroidism; abrupt withdrawal may exacerbate symptoms of hyperthyroidism, including thyroid storm; monitor patient closely and withdraw drug slowly; during IV administration, carefully monitor BP, heart rate, and ECG

Drug Name	Nitroprusside (Nitropress) -- Causes peripheral vasodilation by direct action on venous and arteriolar smooth muscle, thus reducing peripheral resistance. Commonly used IV because of rapid onset and short duration of action. Easily titratable to reach desired effect. Light sensitive; both bottle and tubing should be wrapped in aluminum foil. Prior to initiating nitroprusside, administer beta-blocker to counteract physiologic response of reflex tachycardia that occurs when nitroprusside used alone. This physiologic response will increase shear forces against aortic wall, thus increasing dP/dT. Objective is to keep heart rate at 60-80 bpm.
Adult Dose	0.5-3 mcg/kg/min; rates >4 mcg/kg/min may lead to cyanide toxicity
Pediatric Dose	Administer as in adults
Contraindications	Documented hypersensitivity; subaortic stenosis, idiopathic hypertrophic; atrial fibrillation or flutter
Interactions	None reported
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Caution in increased intracranial pressure, hepatic failure, severe renal impairment, and hypothyroidism; in renal or hepatic insufficiency, levels may increase and can cause cyanide toxicity; sodium nitroprusside has ability to lower BP and thus should be used only in patients with mean arterial pressures >70 mm Hg

Drug Category: Analgesics -- Pain control is essential to quality patient care. It ensures patient comfort, promotes pulmonary toilet, and prevent exacerbations of tachycardia and hypertension.

Drug Name	Morphine sulfate (Astramorph, Infumorph) -- DOC for narcotic analgesia due to reliable and predictable effects, safety profile, and ease of reversibility with naloxone. Like fentanyl, morphine sulfate easily titrated to desired level of pain control. If administered IV, may be dosed in a number of ways; commonly titrated until desired effect obtained.
Adult Dose	Initial dose: 0.1 mg/kg IV/IM/SC Maintenance dose: 5-20 mg/70 kg q4h IV/IM/SC
Pediatric Dose	0.1-0.2 mg/kg q2-4h prn
Contraindications	Documented hypersensitivity; hypotension; potentially compromised airway in which establishing rapid airway control would be difficult
Interactions	Phenothiazines may antagonize analgesic effects; tricyclic antidepressants, MAOIs, and other CNS depressants may potentiate adverse effects
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Avoid in hypotension, respiratory depression, nausea, emesis, constipation, and urinary retention; caution in atrial flutter and other supraventricular tachycardias; has vagolytic action and may increase ventricular response rate

FOLLOW-UP

Section 8 of 11

Further Inpatient Care:

• Patients with symptomatic dissection should undergo immediate repair, especially if it is leaking or expanding

• Symptomatic patients require admission to a center experienced in cardiopulmonary bypass and operative care.

• Completely asymptomatic patients may have their repair performed electively but may require admission to expedite their evaluation or for preoperative stabilization of their condition.

• Patients with chest pain should undergo serial ECGs and CPK determinations if AMI is indicated.

Further Outpatient Care:

• Follow-up examinations with radiologic studies are recommended at 3-month intervals for the first year and every 6 months for the next 2 years.

• After this, follow up annually.

Transfer:

• Symptomatic patients require care at a facility equipped to perform cardiopulmonary bypass with aortic and/or valvular repair.

• Contact the receiving physician as soon as possible to transfer patients before their condition deteriorates.

• Early airway management is indicated in the presence of hemoptysis or stridor.

• If coronary insufficiency is suspected, nitrates may be used, but therapy with thrombolytic agents and aspirin should be avoided.

• Patients should be monitored and accompanied by personnel capable of resuscitation.

• If a prolonged ground transport time is anticipated, consider air transport.

Prognosis:

• On the basis of his experience, Crawford has stated that "no patient should be considered cured of the disease."

• The 5-year survival rate is about 75% whether the patient is treated medically or surgically.

• The 10-year survival rate is between 40% and 69% for both surgically and medically treated dissections.

• In the pretreatment era, the 1-year survival rate was 5-10%.

• Reoperation may be necessary for late complications.

MISCELLANEOUS

Section 9 of 11

Medical/Legal Pitfalls:

• Failure to diagnose the disease in patients presenting with chest pain

• Failure to avoid using thrombolytics in the patient presenting with chest pain and ECG changes

• Multiple case reports describe patients who received thrombolytics and were found later to have a dissection. The diagnosis of aortic dissection can be very subtle.

• The diagnosis depends on clinical suspicion, with contributory history, physical exam, and imaging studies.

• Obtaining a chest radiograph prior to thrombolytics is considered prudent.

• Checking blood pressures in both arms and listening for carotid bruits also can help diagnose aortic dissection prior to thrombolytics. The entire clinical picture must be taken into account.

PICTURES

Section 10 of 11

Caption: Picture 1. X-ray of a patient with aortic dissection (Courtesy of Dr. K. London, University of California at Davis Medical Center)
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Caption: Picture 2. X-ray of a patient with aortic dissection presenting with hemothorax
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Caption: Picture 3. X-ray demonstrating widened mediastinum in a patient with aortic dissection
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Caption: Picture 4. Angiogram demonstrating dissection of the aorta (See Picture 3 for the chest x-ray of this patient.)
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Caption: Picture 5. Electrocardiogram of a patient presenting to the ED with chest pain who has been diagnosed with aortic dissection
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BIBLIOGRAPHY

Section 11 of 11

• Bickerstaff L, Pairolera P, Hollier L: Thoracic Aortic Aneurysm: A Population Based Study. Surgery 1982; 92: 1103-1108[Medline].
• Chen K, Varon J, Wenker OC, et al: Acute thoracic aortic dissection: the basics. J Emerg Med 1997 Nov-Dec; 15(6): 859-67[Medline].
• Cigarroa J, Isselbacher E, DeSanctis R: Diagnostic Imaging in the Evaluation of Suspected Aortic Dissection. N Engl J Med 1993; 328(1): 35-43[Medline].
• DeBakey M, Cooley D, Creech O: Surgical Considerations of Dissecting Aneurysm of the Aorta. Ann Surg 1955; 142: 586-612.
• DeBakey M, Cooley D: Successful Resection of Aneurysm of Thoracic Aorta and Replacement by Graft. JAMA 1953; 152: 673-676.
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• Erbel R, Engberding R, Roelandt J: Echocardiography in the Diagnosis of Aortic Dissection. Lancet 1989; 1: 457-461[Medline].
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• Hagan PG, Nienaber CA, Isselbacher EM: The International Registry of Acute Aortic Dissection (IRAD): New Insights Into an Old Disease. JAMA 2000; 283: 897-903.[Medline].
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• Krukenberg E: Beitrage zur Frage des Aneurysma Dissecans. Beitr Pathol Anat Allerg Pathol 1920; 67: 329-351.
• Nichols F: Observations Concerning the Body of His Late Majesty. Philos Trans Lond 1762; 52: 265-275.
• Pansini S, Garliardotto P, Pompei E: Early and Late Risk Factors in Surgical Treatment of Acute Type A Aortic Dissection. Ann Thorac Surg 1998; 66: 779-784[Medline].
• Ponraj P, Pepper J: Aortic dissection. Br J Clin Pract 1992 Summer; 46(2): 127-31[Medline].
• Prokop EK, Palmer RF, Wheat MW Jr: Hydrodynamic forces in dissecting aneurysms. In-vitro studies in a Tygon model and in dog aortas. Circ Res 1970 Jul; 27(1): 121-7[Medline].
• Safi H, Miller C, Reardon M: Operation for acute and Chronic Aortic Dissection:Recent Outcome with Regard to Neurologic Deficit and Early Death. Ann Thorac Surg 1998; 66(2): 402-411[Medline].
• Sarasin F, Gaspoz J, Junod A, et al: Detecting Acute Thoracic Aortic Dissection in the Emergency Department: Time Constraints and the Choice of the Optimal Diagnostic Test. Ann Emerg Med 1996; 28(3): 278-288[Medline].
• Spiegel EA, Wassreman S: Experimentalstudien uber die Entsehungdes Aortenschmerzes und seine Leitung zum zentralnervensystem. Ztschr F. d. ges. Exper Med 1926; 52: 180-196.
• Svensson L, Crawford E, Hess K: Experience With 1509 Patients Undergoing Thoracoabdominal Aortic Operations. J Vasc Surg 1993; 17: 357-370[Medline].
• Wooley C, Sparks E, Boudoulas H: Aortic pain. Prog Cardiovasc Dis 1998; 40(6): 563-589[Medline].

NOTE:

Medicine is a constantly changing science and not all therapies are clearly established. New research changes drug and treatment therapies daily. The authors, editors, and publisher of this journal have used their best efforts to provide information that is up-to-date and accurate and is generally accepted within medical standards at the time of publication. However, as medical science is constantly changing and human error is always possible, the authors, editors, and publisher or any other party involved with the publication of this article do not warrant the information in this article is accurate or complete, nor are they responsible for omissions or errors in the article or for the results of using this information. The reader should confirm the information in this article from other sources prior to use. In particular, all drug doses, indications, and contraindications should be confirmed in the package insert. FULL DISCLAIMER

eMedicine Journal, January 25 2002, Volume 3, Number 1

Dissection, Aortic excerpt

© Copyright 2002, eMedicine.com, Inc.

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