Aortic Disease

Aortic Aneurysm Defined asDefined as an abnormal dilatation of the aortic lumen; a true aneurysm involves all the layers of the wall, whereas a false aneurysm does not. Categorized morphologically as either fusiform or saccularCategorized morphologically as either fusiform or saccular Categorized anatomically by locationCategorized anatomically by location

Aortic Aneurysm (Anatomic Classification) Ascending aneurysms: (60%) Aortic arch: (10%) Descending aorta: (40%) Thoracoabdominal aorta (10 %)

Aneurysm Etiology Cystic medial degeneration leading to weakening of the aortic wall Associated with normal aging. Accelerated by hypertension Associated with connective tissue disorders when found in younger age patients

Aneurysm Etiologies (cont’d) Descending aortic aneurysms are highly associated with atherosclerosis and, hence, atherosclerosis risk factors:Descending aortic aneurysms are highly associated with atherosclerosis and, hence, atherosclerosis risk factors: –Hypertension –Hypercholesterolemia –Smoking genetic factors Aortitis

Marfan’s syndrome This disorder of connective tissue is inherited as an autosomal dominant trait.Affected systems include the skeleton (arachnodactyly, joint hypermobility, scoliosis, chest deformity and high arched palate), the eyes (dislocation of the lens) and the cardiovascular system (aortic disease and mitral regurgitation). Weakening of the aortic media leads to aortic root dilatation aortic regurgitation and aortic dissection

Thoracic aortic aneurysm These may produce chest pain, aortic regurgitation, compressive symptoms such as stridor (trachea, bronchus) and hoarseness (recurrent laryngeal nerve), and superior vena cava syndrome.If they erode into adjacent structures e.g. aorto- oesophageal fistula, massive bleeding occurs.

Abdominal aortic aneurysms (AAAs) AAAs are present in 5% of men aged over 60 years and 80% are confined to the infrarenal segment.. Men are affected three times more commonly than women. AAA can present in a number of ways.The usual age at presentation is 65–75 years. Ultrasound is the best way of establishing the diagnosis, and of following up patients with asymptomatic aneurysms. CT provides more accurate information.

Aneurysm Management SugerySugery –>5.5cm requires consideration for repair –>6 cm has a 50% rupture rate in 5 years –Mortality for acute rupture repair approaches50% –Elective repair has a much lower mortality –Distal embolisation is a strong indication for repair. –As experience with endovascular stenting and repair increases, recommendations may change

Aneurysm Management Medical therapy during observation involves: –SMOKING CESSATION –ß blockade –Other antihypertensive? –Statin therapy

Aortic Dissection A breach in the integrity of the aortic wall allows arterial blood to enter the media, which is then split into two layers, creating a ‘false lumen’ alongside the existing or ‘true lumen’.The aortic valve may be damaged and the branches of the aorta may be compromised. Typically, the false lumen eventually re-enters the true lumen, creating a double-barrelled aorta, but it may also rupture into the left pleural space or pericardium with fatal consequences.

Aortic Dissection

Factors that may predispose to aortic dissection Hypertension (80% of cases) Aortic atherosclerosis Non-specific aortic aneurysm Aortic coarctation Collagen disorders (e.g. Marfan’s syndrome) Previous aortic surgery (e.g. CABG, aortic valve replacement) Pregnancy (usually third trimester) Trauma Iatrogenic (e.g. cardiac catheterization).

Clinical Manifestations Involvement of the ascending aorta typically gives rise to anterior chest pain, and involvement of the descending aorta to intrascapular pain. The pain is typically described as ‘tearing’ and very abrupt in onset; collapse is common. There may be asymmetry of the brachial, carotid or femoral pulses and signs of aortic regurgitation. Occlusion of aortic branches may cause MI,stroke,paraplegia,mesenteric infarction with an acute abdomen,renal failure (renal) and acute limb (usually leg) ischaemia.

Investigations The chest X-ray characteristically shows broadening of the upper mediastinum. ECG may show left ventricular hypertrophy in patients with hypertension, or rarely changes of acute MI (usually inferior). Doppler echocardiography may show aortic regurgitation, a dilated aortic root and, occasionally, the flap of the dissection. Transoesophageal echocardiography is particularly helpful because transthoracic echocardiography can only image the first 3–4 cm of the ascending aorta). CT and MRI angiography are both highly specific and sensitive.

Aortic Dissection Classification Stanford Classification Type A, involving the ascending aorta, regardless of point of entry. Type B, involving the descending aorta,(ie from the left subclavian artery distal).

Aortic Dissection Treatment Ascending (type A) dissections are surgical emergencies Mortality rate is 1 to 2 %/hr once diagnosis is made 50% in hospital mortality if unoperated

Aortic Dissection Treatment Type B (descending aortic) dissection can be managed medically ICU admission Blood pressure control –IV ß blockers –labetelol –nitroprusside

Type B dissection Indications to proceed to surgery –Complications including Branch occlusion Continued aortic expansion Dissection extension Aortic rupture Marfan syndrome