Aortic Dissection

Prof. Dr. Mohamed Z. Khalil,MD, ABIM, SBIM, MRCP (UK), FACC,

FESC, FKSUConsultant physician & Cardiologist

Background:

• The first well-documented case of aortic dissection:

King George II of England (1683 - 1760) died while

straining on the commode!

1910: William Osler

• ". . . spontaneous tear of the arterial coats is associated with atrocious pain, with symptoms, indeed, in the case of the aorta of angina pectoris and many instances have been mistaken for it."

1955

• The first successful operative repair was performed by DeBakey.

Prevalence:

• 0.2 - 1% of all autopsies.• Aortic dissection is more common in blacks

than in whites.• Less common in Asians than in whites.• Male-to-female ratio is 3:1.

Localization and Incidence of Initial Pain inPatients With Aortic Dissection

Site of Pain Patients, No. % of Total (n = 72)

• Anterior chest 46 64.0• Back 7 9.7• Neck 2 2.8• Throat 1 1.4• Head (face and jaw) 2 2.8• Epigastrium 7 9.7• Groin 1 1.4• Without pain 6 8.3

Main Clinical Diagnoses of 66 PatientsWith Aortic Dissection

• Diagnosis No. of Cases %

• Aortic dissection 19 28.8• Acute myocardial infarction 21 31.8• Stroke 8 12.1• Pulmonary embolism 7 10.6• Acute heart failure 5 7.6• Acute pancreatitis 2 3.0• Mesenteric thrombosis 2 3.0• Aortic stenosis 1 1.5• Unstable angina 1 1.5

Causes of Death in Patients With Aortic Dissection

• Cause of Death No. of Cases % of Total, (n =

82)• Pericardial hematoma 57 69.5• Left intrapleural hematoma 8 9.8• Chronic heart failure 5 6.1• Mesenteric thrombosis 4 4.9• Acute heart failure 2 2.4• Right intrapleural hematoma 1 1.2• Bilateral intrapleural hematoma 1 1.2• Subpleural hematoma 1 1.2• Mediastinal hematoma 1 1.2• Cerebral anoxia 1 1.2• Acute myocardial infarction 1

CHEST 2000

K.S.M.C.Riyadh

KSA

History • 24 years Saudi male, not known to have any

medical problem.

• Presented to ER of RMC referred from: King Khalid International airport hospital C/O sever chest pain for 2 hours started while working in the airport.

• The pain was of:• Sudden onset, • Retro-sternal, • Radiating to the back between the two scapulae, • Associated with S.O.B. nausea but no vomiting.

• There was no aggravating or relieving factors.

• There was no Hx. of similar attack• Past medical & surgical Hx. –ve• Drug or allergy Hx. –ve

• Family members are healthy. • No family history of Marfan syndrome.

• None smoker or ETOH consumer.• Newly married 6/12. • Working as passport officer in the airport.

Examination

• Anxious distressed young male.• V/S: R.R:25/min. Pulse:100/min. T:37• Bp: 140/90• Chest: clear.• C.V.S : S1, S2• Abdomen: WNL• C.N.S: no focal deficit.

What important physical sign?

• B/P: • RT. Arm :140/90 LT. Arm :130/80• RT. Leg :130/90

LT .Leg :120/80

• Variable femoral pulsation (asymmetrical)

Investigations:• CBC: WBC:21.4 HB:13.9 PLAT:500• Na: 137• K: 4.7• Urea:4.3 Creat.:77 • glucose: 7.4• L.D.H: 228• C.K:81 (repeated x 2 = N)• I.N.R:1.09• P.T.T: 26.1 seconds.

Fig. 1 EKG showing SR, LAD, minor IV conduction defect, poor progression of R waves

Urgent echo

Cont.

Cont.

Cont.

Management

1-Control of H.R. B/P : atenolol 50 mg p.o. H.R.:70/m reg. B/P:100/60

2-uregent cardiac surgery referral (fax sent from the E.R ).

3- transferred to K.K.U.H. cardiac center O.R.(End to end with Dacron graft)

4-discharged home after 4 days.

Natural history:

• Aortic dissection is the most common catastrophe of the aorta.

• 40% of proximal aorta died immediately!• Rate of death 1-3% per hour.• 33% of patients die within the first 24 hours• 50% die within 48 hours.• 75% die in 2 weeks.• 100% die in 5 weeks.

PATHOPHYSIOLOGY

• Tear in aortic intima• Degeneration of aortic media• Cystic medial necrosis• The right lateral wall of the ascending aorta

is the most common site of aortic dissection

Larson, et al. Risk factors for aortic dissection: A necropsy study of 161 cases. Am J Cardiol 1984

• Blood passes into the aortic media through the tear creating a false lumen.

• Multiple communications may form between true and false lumen.

Dissection sites:

• 90% occurring within 10 centimeters of the aortic valve.

• The second most common site is just distal to the left subclavian artery.

• 5% and 10% of dissections do not have an obvious intimal tear.

Predisposing factors:• Sex: male• Age: 60-80• Hypertension• Takayasu arteritis• Giant cell arteritis• Rheumatoid arthritis• Syphilitic aortitis

• Marfan syndrome (8.5%)• Ehlers-Danlos syndrome• Cystic medial necrosis• Bicuspid aortic valve• Aortic coarctation• Turner syndrome• Crack cocaine• Trauma

Classification:• DeBakey system:-Type I: both ascending and descending thoracic

aorta-Type II: ascending aorta-Type III: descending aorta

DeBakey, et al. Surgical management of dissecting aneurysms of the aorta.J Thorac Cardiovasc Surg 1965.

Classification:• The Daily system (Stanford):-Type A: the ascending aorta.-Type B: all other dissections.

Daily, et al. Management of acute aortic dissections. Ann Thorac Surg 1970.

CLINICAL MANIFESTATIONS:

• Severe, sharp or "tearing" chest pain.• Pain may radiate anywhere in the thorax, back, or

abdomen.• Hypertension (70%).• Pulse deficit (19-30% type A, 9% type B).• Syncope (13%). • Cerebrovascular accident.• Myocardial infarction.• Heart failure.• Painless (rare).• Acute AR (50-76%).

• Cardiac tamponade.• Hemothorax.• Variation in blood pressure (>30 mmHg).• Neurologic deficits.• Horner syndrome (compression of the superior cervical sympathetic ganglion).• Hoarseness (compression of the left recurrent laryngeal nerve).

Differential diagnosis• • Acute coronary syndrome• • Pericarditis• • Pulmonary embolus• • Aortic regurgitation without dissection• • Aortic aneurysm without dissection• • Musculoskeletal pain• • Mediastinal tumors• • Pleuritis• • Cholecystitis• • Atherosclerotic or cholesterol embolism• • Peptic ulcer disease or perforating ulcer

Warning: you can miss the diagnosis in nearly ½ of the

patients

• Correctly diagnosed patients ante mortem in large series of autopsies ranged from 40.4% to 84%

• Hirst AE, et al. Dissecting aneurysm of the aorta. A review of 505 cases. Medicine 1958

• Anagnostopoulos CE. Diagnosis of aortic dissection. In: Anagnostopoulos CE (ed). Acute aortic dissections.University Park Press, Baltimore, 1975

DIAGNOSIS:

I- Clinical features:• 1- Tearing chest pain• 2- Variation in pulse or Bp• 3- Mediastinal widening on CXR (A=63%, B=56%)• (1+2+3 are found in 77% of aortic dissections)

Von Kodolitsch, et al. Clinical prediction of acute aortic dissection. Arch Intern Med 2000

II- EKG:• 1- normal in 31%• 2- nonspecific ST/T wave changes in 42%• 3- ischemic changes in 15%• 4- acute MI in 5%

Hagan, et al. The International Registry of Acute Aortic Dissection (IRAD): new insights into an old disease. JAMA 2000

III-Imaging:1- CT chest in 61% (sn=83%, sp=100%)2- Echocardiography in 33% 3- MRI/MRA (sn=100%, sp=94%)4- Aortography in 4% (sn=88%, sp=94%)

Hagan, et al. The International Registry of Acute Aortic Dissection (IRAD): new insights into an old disease. JAMA 2000

Echocardiography

TTE:1- limited utility2- poor sn & sp3- inferior to CT, MRI, TEETEE:1- sn=98%, sp=95%2- can be easily performed in ER3- useful in patients too unstable for MRI

What is the image of first choice for evaluating suspected AD?

Management strategy

• TYPE A require urgent surgical correction to avoid

extension into coronary or carotid arteries and tamponade.

• TYPE B could be managed medically or surgically.

The key for medical Rx:

Systolic pressure < 100-110mmhg

Shearing force Contractility

preventing propagation of the dissection

Surgical management• Ascending aorta: 1- obliterate the most proximal intimal tear. 2- restore competency of the aortic valve. 3- restore flow to any branch of the aorta that is receiving

blood flow from false lumen 4- protect the heart during these maneuvers and restore the

coronary blood flow. 5- look for tears in the transverse aortic arch.

• Descending dissection:

1- to close off the hematoma by obliterating the most proximal intimal tear.

2-to restore blood flow to branches of the aorta fed by the false channel.

Surgical techniques:

• OPERATIVE Complication:– Hemorrhage 20%– Renal failure 20%– Pulmonary embolism 30%– Acute myocardial infraction 30%– Bowel infraction 5%– Death 15%– Paraplegia (usually only with descending

dissection)

Poor prognostic factors:• • Hypotension, shock, or tamponade• • Renal failure at presentation and before surgery• • Age >70 years• • Abrupt onset of chest pain• • Pulse deficit• • Abnormal ECG, particularly ST segment elevation• • Prior myocardial infarction• • Renal and/ or visceral ischemia• • Underlying pulmonary disease .• • Preoperative neurologic impairment• • Perioperative bleeding and massive blood transfusion• • Prolonged clamping time

Prognosis:

• 10 year survival = 30-60%• Re operation = 28% (7 year F/U)• Residual dissection = 78%

Conclusions:

• Acute ascending aortic dissection is included in the differential diagnosis of patients with acute chest pain.

• Aortic dissection is considered as the most common disaster of aorta.

• Stanford type A dissection is a surgical emergency that requires urgent diagnosis and immediate surgical intervention.