Aortic Dissection ================= See also: Aneurysms þ Physical Exam Features in Patients with Incidental, Expanding, or Ruptured AAAs: Incidentally Expanding Ruptured Physical Exam Feature found AAA AAA AAA ----------------------------------------------------------------------- Pulsatile abd. mass 51% 88% 70% Abdominal tenderness 8% 32% 41% Triad: pain, pulsatile < --- 30 - 40% mass and hypotension Abdominal bruit 3% 8% 0% Absent pulses 32% 18% 6% Gangrenous toes 0% 0% 4% Anuria 0% 2% 0% Adapted from: [Marston WA, Alquist R, Johnson G et al. Misdiagnosis of ruptured abdominal aneurysms. J Vasc Surg 1992; 16:17-22.] -- John D. Patrick, MD, FACEP þ Aortic Dissection Statistics - 2000/yr indicdence in US - Untreated mortality 90% at 3 months - Treated mortality 40% at 10 years (60% if leave hospital alive) þ Aortic Dissection Classification - DeBakey system: site and extent Type I: tear in ascending aorta, hematoma extends beyond brachiocephalic artery Type II: tear in ascending aorta, hematoma just in ascending aorta Type III: tear in descending aorta, near ligamentum arteriosum just distal to left subclavian artery IIIA: stays above the diaphragm IIIB: goes below the diaphagm - Stanford University system: A: affect the ascending aorta (surgical Rx best) B: don't affect ascending aorta (medical Rx best) - acute/chronic system dividing line is 2 weeks of symptoms. þ Risk Factors for Aortic Dissection - male sex - age over 50 - hypertension (found in more than 2/3 of cases) - Marfan's and Ehlers-Danlos syndromes (medial degeneration) - congenital deformities of aortic valves (e.g., bicuspid aortic valve) - deceleration injury - iatrogenic (cardiac or other catheterization) - NOT atherosclerosis - cocaine (although no more Type A than in controls) [Eagle KA et al. Cocaine-related aortic dissection in perspective. Circulation 2002 Apr 2; 105:1529-30.] - rheumatoid arthritis, scleroderma, Behcet's syndrome, ankylosing spondylitis may cause aortitis. þ Presentation of Aortic Dissection - commonly mistaken for MI - tearing pain in chest; may be confusing as may have orthopnea, hemoptysis, EKG changes, syncope, paralysis, blindness þ Cystic Medial Necrosis (old term) = Medial Degeneration (new term) - NOT cystic, NOT necrosis - normal part of aging - increased in patients with HTN and aortic dissection - accelerated in Marfan's, Ehlers-Danlos þ Possible Causes: - repetitive flexion - congenital weakening - disrupted laminar flow: bicuspid valve - upper body HTN: coarctation - pregnancy = hyperdynamic heart þ Possible Symptoms of Dissection: - hemoptysis (rupture into lung) - hoarseness (pressure on recurent laryngeal nerve) - Horner's syndrome (pressure on sympathetics) - hemiplegia - SVC syndrome - MI - pseudohypotension (from compresssion of arteries to arms) þ Diagnosis - CXR: + mediastinal widening + change in aortic contour + obliteration of aortic knob + pleural effusion + displacement of NG tube or ET tube - retrograde aortogram + used to be gold standard + shows direct and indirect signs, good view of anatomy + 80-90%, specificity 90% [Erbel at al, Lancet 1989] - CT + time consuming, IV contrast, misses many indirect signs (coronary or branch artery involvement) + IDs other causes of mediastinal widening + Sensitivity 90%, specificity 95% [Neinaber, NEJM 1993] "In a study from UK using a fast CT system the overall sensitivity for aortic dissection (types A & B together) was 96.2% and specificity 96.4%. The full text of that article is in Br J Radiol 1996 Oct;69(826):900-905" + Ultrafast CT is best. - MRI: + Sensitivity high, especially cine-MRI + regular (non-cine) MRI 100% sensitive and specific for diagnosis but not as good for site of entry [Neinaber et al, Circulation 1992] - Transesophageal Echocadiogram + very sensitive, can be done in ED (safer) + false positives from calcific changes + if use definite criteria, can make test 100% specific and sensitive [(retrospective) Cigarroa et al, NEJM 1993] þ ED Management - consider a-line and/or CVP - pain control - decrease rate of rise of arterial pulse (dP/dT), by treating HTN: þ Definitive Management: - Type A (surgical): only contraindication is simultaneous CVA in evolution + 5-10% mortality - Type B (medical): + Medical management mortality is 15-20%, about same as if do surgery + Continue antihypertensive + surgery if: aortic rupture, persistent pain, uncontrollable HTN, occlusion of aorta or major branch such as renal, distal aorta more than 5 cm. þ Rupture of thoracic aorta - 80-90% die instantly; of remaining untreated cases, mortality is 30% at 6 hours, 49% at 24 hours, 72% at 8 days, 90% at 4 months; easy to cure surgically. - 85% are in descending aorta at isthmus/ligamentum arteriosum (9% at aortic root) - suspect if chest pain, dyspnea, hoarseness, dysphagia, extremity pain, usually with other severe injury (rare in the minor-injury MVA patient per Eric Swanson's literature research), hyper- or hypotension, first or second or multiple rib fractures. - only 76% have wide mediastinum - 73% of those with wide mediatinum will have normal angiography/CT - diagnosis: + surgeons tend to favor aortograms as is gold standard; but if pretest probability is low, consider CT. + TEE has 100% sensitivity, 98% specificity (93 patients) [Smith et al, NEJM Feb 9 1995] (from Kentucky) But,TEE has "blind spot" near the arch, and so can miss injury of the great vessels (e.g., innominate artery). - management: + control HTN, manage other problems. + Generally want SBP 110-120 unless severely hypertensive due to essential HTN or brain injury (reduce more gradually) þ Radiological Criteria for Aortic Injury [Mirvis et al, Radiology, 1987.]