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This presentation provides an overview of ruptured and dissecting aneurysms, including differential diagnosis, workup, treatment, and medication options. It covers the classification of thoracic aortic dissections and discusses the pathophysiology, common dissection sites, and diseases that predispose individuals to dissection. The frequency, mortality, race/sex/age distribution, and clinical evaluation of aortic dissections are also examined. The presentation concludes with a discussion on differential diagnosis and evaluation, including laboratory and imaging studies.
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RUPTURED / DISSECTINNG ANEURYSMS Christopher B. Powe, Ph.D., ACNP-BC President|Priniciple Global Training Institute, LLC
Objectives • Overview • Differential Diagnosis & Workup • Treatment and Medication • Follow up
Overview • Aortic dissection most common catastrophe of aorta • 2-3 times more common than rupture of abdominal aorta • Untreated • 33% patients die within first 24hrs • 50% die within 48hours • 2-week mortality rate approaches 75% in undiagnosed ascending aortic dissection
Overview • Dissections of thoracic aorta classified anatomically by 2 different methods • Stanford Classification • Debakey Classification • Stanford: • Type A: involves ascending aorta • Type B: does not involve ascending aorta • Debakey: • Type I: ascending aorta, aortic arch, descending aorta • Type II: confined to ascending aorta • Type III: confined to descending aorta distal to LSC artery
Overview • Thoracic aortic dissections should be distinguished from aneurysms • i.e. localized abnormal dilation of aorta • Transections are caused most commonly by high-energy trauma
Pathophysiology • Essential features • Aortic dissection is a tear in the intimal layer • Followed by formation subintimal hematoma • Hematoma commonly occupies about ½ circumference of the aorta • Produces a false lumen: • Reduces blood flow to major arteries • Cystic Medial Necrosis • Normal aorta contains collagen, elastin and smooth muscle (initima, media, adventitia) • Degenerative changes lead to breakdown of collagen, elastin • Termed cystic medial necrosis • Atherosclerosis produces this disorder
Dissection Sites • Most common sites • First few cm of ascending aorta • 90% occur within 10cm of aortic valve • Second most common • Just distal to the left subclavian artery • 5-10% if dissections do not have an obvious intimal tear
Diseases leading to Dissection • Marfan • Ehlers-Danlos • Other connective tissue disorders • All affect the media of the aorta • Pulsative flow and high blood pressure propugate dissection • Diseases that weaken the aortic wall predispose patient to aortic dissection • Shearing forces separate layers in the media of the aorta
Frequency/Mortality • Frequency • True incidence difficult to estimate • Most based on autopsy studies • 6-10 new aneurysms per 100,000 person-years • Dissection is found 1-3% of all autopsies • Mortality/Morbidity • 1-2% of patients with aortic dissection die per hr for the first 24-48h • Incidence increases in pregnancy, syphilis , crack cocaine use and cardiac catheterization (iatrogenic)
Race/Sex/Age • Race • Aortic Dissection more common in blacks • Less common in Asians than in whites • Sex • Male to Female ration is 3:1 • Age • 75% of dissections occur in those aged 40-70 years • Peak 50-65 years old
Clinical Evaluation • No ONE sign or symptom can positively ID acute aortic dissection • 38% AAD are missed on initial evaluation • No validated clinical decision rules to ID AAD • High clinical suspicion coupled with exam, diagnostics and radiology • Chest pain is the most common presenting symptom in patients with AAD • Described as ripping or tearing • Sudden acute pain sensitivity of 84%
Clinical Evaluation • Presenting signs and symptoms of AAD: • Anterior chest pain: ascending aortic dissection • Neck or jaw pain: aortic arch dissection • Intrascapular tearing/ripping: descending aorta • Myocardial infarction • Neurologic symptoms • Syncope • Stroke symptoms • Limb parasthesias, pain or weakness
Differential Dx / Evaluation • Differential Dx • Aortic Regurgitation • Aortic Stenosis • Back pain, mechanical • Gastroenteritis • Hernias • Hypertensive emergencies • Myocardial infarction • Pulmonary Embolism
Laboratory Studies • BUN / Creatinine (dissection involves renal arteries) • Troponin / Creatine Kinase (MI) • Hemoglobin/Hematocrit (decreased) • D-dimer (presences less likely with negative) • Hematuria, oliguria, anuria
Imaging Studies • Chest Radiography • Findings are abnormal in 80% of patients • Commonly abnormal in ascending aortic dissection • Findings suggesting hemothorax if rupture into pleura • Widened mediastinum may be present • Only about 25% demonstrate this finding
Radiography Chest radiograph of a patient with aortic dissection.
Radiography Chest radiograph of a patient with aortic dissection presenting with hemothorax.
Radiography Chest radiograph demonstrating widened mediastinum in a patient with aortic dissection.
Computerized Tomography Aortic dissection. CT scan showing a flap
Computerized Tomography Aortic dissection. CT scan showing a flap
Computerized Tomography Aortic dissection. True lumen and false lumen separated by an intimal flap
Typing & Classification Image A: Stanford A Image B: Stanford A Image C: Stanford B Image D: Stanford A Stanford A: ascending aorta involved Stanford B: descending aorta involved
Treatment • Initiate medical therapy as soon as dx is considered • GOAL: Decrease blood pressure and shearing forces of myocardial contractility • Admit patient to ICU • Arterial line • Central venous access • Urinary output monitoring
Treatment • Initiate therapy to reduce contractility • Negative inotropic drugs • Labetalol IV • Propanolol IV • Esmolol IV • Initiate therapy to reduce systemic arterial pressure • Nitroprusside IV • Labetaolol IV • Calcium channel blockers (Diltiazem)
Surgical Therapy • Major objectives: • Alleviate symptoms • Decrease frequency of symptoms • Prevent aortic rupture and death • Options • Dacron graft placement • Percutaneous fenestrations / stent placements • Area of the aorta with intimal tear is usually resected and replaced with a Dacron graft
Summary • Mortality rate associated with aortic arch dissections is 10-15%. • Medical management remains the treatment of choice for descending aortic dissections unless they are leaking or ruptured.